Documents published in 2017 : Scipedia

Computer applications in railway operation
M. Aly, H. Hemeda, M. El-sayed

Collection of Alexandria Engineering Journal (2017).

Abstract
One of the main goals of the railway simulation technique is the formation of a model that can be easily tested for any desired changes and modifications in infrastructure, control system, or in train operations in order to improve the network operation and its productivity. RailSys3.0 is a German railway simulation program that deals with this goal. In this paper, a railway network operation, with different suggested modifications in infrastructure, rolling stocks, and control system, using RailSys3.0, has been studied, optimized, and evaluated. The proposed simulation program (RailSys 3.0) was applied on ABO-KIR railway line in Alexandria city, as a case study, to assess the impact of changing track configuration, operating and control systems on the performance measures, time-table, track capacity and productivity. Simulation input, such as track element, train and operation components of the ABO-KIR railway line, has been entered to the computer program to construct the simulation model. The simulation process has been carried out for the existing operation system to construct a graphical model of the case-study track including line alignment and train movements, as well as to evaluate the existing operation system. To improve the operation system of the railway line, eight different innovative alternatives are generated, analyzed and evaluated. Finally, different track measures to improve the operation system of the ABO-KIR railway line have been introduced.
Abstract
One of the main goals of the railway simulation technique is the formation of a model that can be easily tested for any desired changes and modifications in infrastructure, [...]
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Wind-induced loads and integrity assessment of hyperboloid reflector of solar power plants
M. Eswaran, R. Verma, G. Reddy

Collection of Alexandria Engineering Journal (2017).

Abstract
Flow-induced loads and Strouhal frequencies of secondary hyperboloid reflector which is located at top of the central tower of a proposed solar power plant are investigated. Initially for validation, flow-induced vibration characteristics of 3-D rectangular cylinder are studied and found in good agreement with previously published results. After the validation of the present numerical procedure, the force coefficients and the Strouhal frequencies of solar secondary hyperboloid reflector are determined for operational and survival wind speeds. Influences of various numerical parameters are investigated through the statistical values of the drag and the lift coefficients, Strouhal number, and pressure distribution. Finite element analysis has also been done to find out the deflections and stresses due to dead weight, imposed loads and wind loads and to optimize the design of hyperboloid and towers.
Abstract
Flow-induced loads and Strouhal frequencies of secondary hyperboloid reflector which is located at top of the central tower of a proposed solar power plant are investigated. [...]
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Foundation analyzing of centrifugal ID fans in cement plants
H. Eskandari, M. Nik, A. Pakzad

Collection of Alexandria Engineering Journal (2017).

Abstract
This research was based on a finite-element model (FEM) of large foundations such as induced draft (ID) fans. Three-dimensional (3D) linear analyses were performed under arbitrary static and dynamic loads for various modulus of elasticity of concrete (Ec) (20, 25, 28 and 30 GPa) and reinforcement (Es) (200, 250, 300 GPa). FEM results were compared with the existing ID fan foundations (laboratory-based evidence) to assess the accuracy of simulations made by the FEM. This study validated what constitutes a major departure from current thinking regarding material properties modeling of concrete under various loads to increase foundation for lifetime.
Abstract
This research was based on a finite-element model (FEM) of large foundations such as induced draft (ID) fans. Three-dimensional (3D) linear analyses were performed under arbitrary [...]
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Determination of loop length, tightness factor and porosity of single jersey knitted fabric
E. Eltahan, M. Sultan, A. Mito

Collection of Alexandria Engineering Journal (2017).

Abstract
After fabric relaxation, there is a reduction in wale and course density due to a reduction in loop length and this actually will affect the fabric properties. Then, it is useful to find a relation between loop length and courses and wales per unit length as well as the yarn thickness because wales and courses per unit length can be easily measured at any state while it is difficult to measure the loop length in the knitted fabrics. Therefore, it is required to find an equation, through which the value of loop length can be easily calculated from the measured values of courses and wales per unit length at any state after the knitting process. In this work estimated equations to calculate the knitted loop length for open to normal structure and for normal to compact structure are developed. By comparing the value of the loop length predicted from this work with the other mentioned models, it was found that the calculated values are very near to the L value of the case study, so the developed equations are acceptable. The tightness factor and the porosity of single jersey fabrics were also calculated theoretically.
Abstract
After fabric relaxation, there is a reduction in wale and course density due to a reduction in loop length and this actually will affect the fabric properties. Then, it is [...]
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Weight optimization of offshore supply vessel based on structural analysis using finite element method
A. Elhewy, A. Hassan, M. Ibrahim

Collection of Alexandria Engineering Journal (2017).

Abstract
Ship design process usually relies on statistics and comparisons with existing ships, rather than analytical approaches and optimization techniques. Designers found this way as the best to fulfil the owner’s requirements, but better solutions, for both the shipyard and the owner may exist. Assessing ship life cycle cost is one of the most attractive tasks for shipyard during early design stage. Structural optimization can be used to achieve that task. In this paper, a comprehensive study on the structural optimization of an offshore supply vessel (OSV), as a case study, is presented. Detailed structural modeling of the vessel is created. Various environmental loads acting on the ship hull such as still water loads and wave induced loads are briefly explained. Different loading conditions and corresponding structural responses have been investigated to assign the most severe one on the vessel. The basic concept of structural optimization and optimization characteristics is highlighted. Blind search optimization technique is applied and approximately forty-two percent weight and cost savings are found by comparing the weight of various design scenarios together without showing any structural inadequacy.
Abstract
Ship design process usually relies on statistics and comparisons with existing ships, rather than analytical approaches and optimization techniques. Designers found this way [...]
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Performance evaluation for solar liquid desiccant air dehumidification system
M. Elhelw

Collection of Alexandria Engineering Journal (2017).

Abstract
In this paper, a solar liquid desiccant air conditioning (SLDAC) system has been studied. The effect of changing evacuated tube collector area on the performance of the SLDAC system was fulfillment. This inquest was done over all a year in Borg Al-Arab city located in the Northern region of Egypt. Meteorological data, such as hourly average solar radiations and temperatures, were needed to achieve this research. The hourly cooling loads were determined by using Hourly Analysis Program (HAP) 4.7. These loads are wall, illumination, people, and equipment loads. Then, the hourly differences of different parameters such as amount of water absorbed in conditioner, amount of water desorbed in regenerator, hot water temperature and coefficient of the performance were calculated. In addition, the maximum solar thermal energy was determined to meet the regeneration demand according to the hourly average solar radiation data. For 220 m2 evacuated tube collector area, the maximum required heat energy is obtained as 38, 286 kW h on December, while using solar energy, will save energy by 30.28% annual value.
Abstract
In this paper, a solar liquid desiccant air conditioning (SLDAC) system has been studied. The effect of changing evacuated tube collector area on the performance of the SLDAC [...]
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Analytical solution of strongly nonlinear Duffing oscillators
A. El-Naggar, G. Ismail

Collection of Alexandria Engineering Journal (2017).

Abstract
In this paper, a new perturbation technique is employed to solve strongly nonlinear Duffing oscillators, in which a new parameter α=α(ε)α=α(ε) is defined such that the value of α is always small regardless of the magnitude of the original parameter εε. Therefore, the strongly nonlinear Duffing oscillators with large parameter ε are transformed into a small parameter system with respect to αα. Approximate solution obtained by the present method is compared with the solution of energy balance method, homotopy perturbation method, global error minimization method and lastly numerical solution. We observe from the results that this method is very simple, easy to apply, and gives a very good accuracy not only for small parameter εbut also for large values of ε.
Abstract
In this paper, a new perturbation technique is employed to solve strongly nonlinear Duffing oscillators, in which a new parameter α=α(ε)α=α(ε) is defined such that the [...]
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Nanoparticles Ni electroplating and black paint for solar collector applications
J. Nady, A. Kashyout, S. Ebrahim, M. Soliman

Collection of Alexandria Engineering Journal (2017).

Abstract
A nanoparticles layer of bright nickel base was deposited on copper substrates using electrodeposition technique before spraying the paint. IR reflectance of the paint was found to be around 0.4 without bright nickel layer and the reflectance increased to 0.6 at a Ni layer thickness of 750 nm. The efficiency of the constructed solar collectors using black paint and black paint combined with bright nickel was found to be better than black paint individually. After aging tests under high temperature, Bright nickel improved the stability of the absorber paint. The collector optical gain FR(τα) was lowered by 24.7% for the commercial paint and lowered by 19.3% for the commercial paint combined with bright nickel. The overall heat loss FR(UL) was increased by 3.3% for the commercial paint and increased by 2.7% for the commercial paint combined with bright nickel after the temperature aging test.
Abstract
A nanoparticles layer of bright nickel base was deposited on copper substrates using electrodeposition technique before spraying the paint. IR reflectance of the paint was [...]
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Nonlinear behavior of RC beams strengthened with strain hardening cementitious composites subjected to monotonic and cyclic loads
A. Khalil, E. Etman, A. Atta, M. Essam

Collection of Alexandria Engineering Journal (2017).

Abstract
Ultra High Performance Strain Hardening Cementitious Composites (UHP-SHCC) are useful for strengthening or repairing concrete members. However there is a need to use refined analytical tools to simulate response of strengthened system. In this study, ABAQUS finite element program is used to numerically perform a parametric study including two major groups. Each group contains nine specimens strengthened from the tension side with variable thickness of UHP-SHCC and reinforced with variable reinforcement ratios embedded in the strengthening layer. Two types of loading were applied: monotonic loading for the first group and cyclic loading for the second group. ABAQUS CPS4R mesh element nonlinear is used to model the concrete, while truss element nonlinear is used to model longitudinal and transverse steel reinforcement. The numerical results obtained are in good agreement with the experimental work found in the literature. The results from the parametric study showed that it is sufficient to use 1.2% additional reinforcement ratio embedded in the strengthening layer for beams strengthened with UHP-SHCC to eliminate the observed early strain localization and to gain adequate ductility under both static and cyclic loadings.
Abstract
Ultra High Performance Strain Hardening Cementitious Composites (UHP-SHCC) are useful for strengthening or repairing concrete members. However there is a need to use refined [...]
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The Application of Gorman’s Eigen Values to The Industrial Sewing Machine’s Needle Vibration
S. Gholmy, I. Hawary

Collection of Alexandria Engineering Journal (2017).

Abstract
The free vibration of the sewing needle is divided into lateral free vibrations and an axial free vibration. In this work a theoretical study that concerns the free lateral vibrations will be applied to the sewing needle by the use of Gorman’s Eigen values (Daniel, 1975) technique. The study will be divided into the following: needles with constant cross-section (with classical and non classical boundary conditions) and needles with variable cross-section (conical and stepped). For all the different shapes of needles (Gorman’s classifications) the linear natural frequency in stitches per min (SPM) will be calculated by the use of Gorman’s Eigen values via special tables and graphs. It was found that the linear fundamental natural frequencies of the following: clamped free sewing needle (CF) is 21, 548 SMP, clamped simple sewing needle (CS) is 94, 522 SMP while for free–free needle (FF) for n = 2 is 137, 130 SMP. For each type the Eigen value β was selected due to the sewing needle boundary conditions. The ratio between the lowest (CF) linear natural frequency and the highest (FF) one is 16%. In this work the selected sewing needle material was steel with E = 206 GPa and specific weight 785, 000 N/m3.
Abstract
The free vibration of the sewing needle is divided into lateral free vibrations and an axial free vibration. In this work a theoretical study that concerns the free lateral [...]
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Long term study of mechanical properties, durability and environmental impact of limestone cement concrete
A. Diab, A. Elmoaty, A. Aly

Collection of Alexandria Engineering Journal (2017).

Abstract
In this study, properties of limestone cement concrete containing different replacement levels of limestone powder were examined. It includes 0%, 5%, 10%, 15%, 20% and 25% of limestone powder as a partial replacement of cement. Silica fume was added incorporated with limestone powder in some mixes to enhance the concrete properties. Compressive strength, splitting tensile strength and modulus of elasticity were determined. Also, durability of limestone cement concrete with different C3A contents was examined. The weight loss, length change and cube compressive strength loss were measured for concrete attacked by 5% sodium sulfate using an accelerated test up to 525 days age. The corrosion resistance was measured through accelerated corrosion test using first crack time, cracking width and steel reinforcement weight loss. Consequently, for short and long term, the use of limestone up to 10% had not a significant reduction in concrete properties. It is not recommended to use blended limestone cement in case of sulfate attack. The use of limestone cement containing up to 25% limestone has insignificant effect on corrosion resistance before cracking.
Abstract
In this study, properties of limestone cement concrete containing different replacement levels of limestone powder were examined. It includes 0%, 5%, 10%, 15%, 20% and 25% [...]
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Improvement of biodiesel methanol blends performance in a variable compression ratio engine using response surface methodology
Y. Bharadwaz, B. Rao, V. Rao, C. Anusha

Collection of Alexandria Engineering Journal (2017).

Abstract
The main objective of this work was to improve the performance of biodiesel–methanol blends in a VCR engine by using optimized engine parameters. For optimization of the engine, operational parameters such as compression ratio, fuel blend, and load are taken as factors, whereas performance parameters such as brake thermal efficiency (Bth) and brake specific fuel consumption (Bsfc) and emission parameters such as carbon monoxide (CO), unburnt hydrocarbons (HC), Nitric oxides (NOx) and smoke are taken as responses. Experimentation is carried out as per the design of experiments of the response surface methodology. Optimization of engine operational parameters is carried out using Derringers Desirability approach. From the results obtained it is inferred that the VCR engine has maximum performance and minimum emissions at 18 compression ratio, 5% fuel blend and at 9.03 kg of load. At this optimized operating conditions of the engine the responses such as brake thermal efficiency, brake specific fuel consumption, carbon monoxide, unburnt hydrocarbons, nitric oxide, and smoke are found to be 31.95%, 0.37 kg/kW h, 0.036%, 5 ppm, 531.23 ppm and 15.35% respectively. It is finally observed from the mathematical models and experimental data that biodiesel methanol blends have maximum efficiency and minimum emissions at optimized engine parameters.
Abstract
The main objective of this work was to improve the performance of biodiesel–methanol blends in a VCR engine by using optimized engine parameters. For optimization of the [...]
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Hall effects on an unsteady magneto-convection and radiative heat transfer past a porous plate
S. Das, S. Guchhait, R. Jana, O. Makinde

Collection of Alexandria Engineering Journal (2017).

Abstract
Hall effects on an unsteady magnetohydrodynamic (MHD) free convective flow of a viscous incompressible electrically conducting optically thick radiating fluid past a vertical porous plate in the presence of a uniform transverse magnetic field are examined. The governing equations are solved numerically using the fourth-order Runge–Kutta–Fehlberg method with the shooting technique. Effects of the pertinent parameters on the flow field, temperature distribution, shear stresses and rate of heat transfer at the plate are presented in graphs and tables followed by a quantitative discussion. The results reveal that the flow field and the temperature distribution are greatly influenced by thermal radiation parameter. Hall currents moderate the flow field significantly. Suction (or injection) has a profound effect on the boundary layer thickness in which the suction reduces the thermal boundary layer thickness whereas injection thickens it.
Abstract
Hall effects on an unsteady magnetohydrodynamic (MHD) free convective flow of a viscous incompressible electrically conducting optically thick radiating fluid past a vertical [...]
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Hydromagnetic double-diffusive mixed convection in trapezoidal enclosure due to uniform and nonuniform heating at the bottom side: Effect of Lewis number
M. Uddin, M. Rahman, M. Khan, R. Saidur, T. Ibrahim

Collection of Alexandria Engineering Journal (2017).

Abstract
This paper presents unsteady numerical results of double diffusive mixed convection flow in a trapezoidal enclosure with the uniform magnetic field effect applied in negative horizontal direction. At the bottom wall, the uniform and non-uniform heat and mass are applied while the heat and mass absorbed uniformly at the top wall. Other side walls are impermeable and adiabatic. The top wall moves along x-axis direction with a constant velocity. The transport phenomenon of this problem can be expressed by the coupled governing equation derived from the conservation of mass and momentum along with the energy equation for temperature and concentration. The finite element method (FEM) based on Galerkin weighted residual technique is used to compute the numerical result from these governing equations. The numerical computation is carried out for Lewis number (Le = 0.1–50) and Richardson’s number (Ri = 0.1–100). Computed numerical results of mass, temperature and velocity distribution are expressed graphically as iso-concentration lines, isotherm lines and streamlines respectively. Average Sherwood and Nusselt number values are used to show the mass and heat transfer rate from the heated and concentrated surface of the enclosure. It is found from the analysis that mass transfer strongly depends on Lewis number. Heat and mass transfer for uniformly heated and concentrated bottom wall is larger than the non-uniformly heated and concentrated bottom wall. Finally, a correlation has been done for average Nusselt and Sherwood numbers for both of the cases.
Abstract
This paper presents unsteady numerical results of double diffusive mixed convection flow in a trapezoidal enclosure with the uniform magnetic field effect applied in negative [...]
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Simultaneous effects of slip and MHD on peristaltic blood flow of Jeffrey fluid model through a porous medium
M. Bhatti, M. Abbas

Collection of Alexandria Engineering Journal (2017).

Abstract
In this article, the simultaneous effects of slip and Magnetohydrodynamics (MHD) on peristaltic blood flow of Jeffrey fluid model have been investigated in a non-uniform porous channel. The governing equation of blood flow for Jeffrey fluid model is solved with the help of long wavelength and creeping flow regime. The solution of the resulting differential equation is solved analytically and a closed form solution is presented. The impact of all the physical parameters is plotted for velocity profile and pressure rise. Nowadays, Magnetohydrodynamics is applicable in various magnetic drug targeting for cancer diseases and also very helpful to control the flow. The present analysis is also described for Newtonian fluid (λ1→0)(λ1→0) as a special case of our study. It is observed that magnitude of the velocity is opposite near the walls due to slip effects whereas similar behavior has been observed for magnetic field.
Abstract
In this article, the simultaneous effects of slip and Magnetohydrodynamics (MHD) on peristaltic blood flow of Jeffrey fluid model have been investigated in a non-uniform porous [...]
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Exact solution for thermal boundary layer in Casson fluid flow over permeable shrinking sheet with variable wall temperature and thermal radiation
K. Bhattacharyya, M. Uddin, G. Layek

Collection of Alexandria Engineering Journal (2017).

Abstract
An analysis of thermal boundary layer in the flow of Casson fluid over a permeable shrinking sheet with variable wall temperature and thermal radiation is made. Using similarity transformations, self-similar nonlinear ODEs are obtained from the governing equations. Dual exact solutions of transformed velocity and energy equations are obtained. From the plotted results it can be observed that the temperature inside the boundary layer decreases with Casson parameter and wall mass transfer parameter in first solution and it increases in second solution. Whereas, temperature decreases for larger values of Prandtl number, radiation parameter and power-law exponent for inverse variation along the sheet in both solutions and it enhances with power-law exponent for direct variation along the surface. Also, thermal boundary layer thickness reduces with stronger thermal radiation and inverse variation of wall temperature along the surface and it becomes thicker with direct variation of wall temperature. The rate of heat transfer is less with increasing values of power-law exponent for direct variation along the sheet and for inverse variation it is higher. In graphical representation of temperature field, temperature overshoot is observed in certain cases. So, in some situations heat absorption at surface occurs instead of heat transfer from surface.
Abstract
An analysis of thermal boundary layer in the flow of Casson fluid over a permeable shrinking sheet with variable wall temperature and thermal radiation is made. Using similarity [...]
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A numerical parametric study of mechanical behavior of dry contact slipping on the disc–pads interface
A. Belhocine, W. Omar

Collection of Alexandria Engineering Journal (2017).

Abstract
The aim of this contribution was to present a study based on the determination and the visualization of the structural deformations due to the contact of slipping between the disc and the pads. The results of the calculations of the contact described in this work relate to displacements, Von Mises stress on the disc, and contact pressures on the inner and outer pad at various moments of simulation. We first proceed to view the meshed models and predicting variations of tensile or compressive stress normal to the plane and shear stress in rotating disc and ring bodies. One precedes then the influence of some parameters on the computation results such as rotation of the disc, the smoothness of the mesh, the material of the brake pads and the friction coefficient entering the disc and the pads, the number of revolutions and the material of the disc, the pad groove.
Abstract
The aim of this contribution was to present a study based on the determination and the visualization of the structural deformations due to the contact of slipping between [...]
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Dual-well potential field function for articulated manipulator trajectory planning
A. Badawy

Collection of Alexandria Engineering Journal (2017).

Abstract
A new attractive potential field function is proposed in this paper for manipulator trajectory planning. Existing attractive potential field constructs a global minimum through which maneuvering objects move down the gradient of the potential field toward this global minimum. The proposed method constructs a potential field with two minima. The purpose of these two minima is to create a dual attraction between links rather than affecting each link by the preceding one through kinematic constraints.
Abstract
A new attractive potential field function is proposed in this paper for manipulator trajectory planning. Existing attractive potential field constructs a global minimum through [...]
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Exploring delay causes of road construction projects in Egypt
R. Aziz, A. Abdel-Hakam

Collection of Alexandria Engineering Journal (2017).

Abstract
Construction delays are a common phenomenon in civil engineering projects in Egypt including road construction projects. Therefore, it is essential to study and analyze causes of road construction delays. This paper studied a list of construction delay causes gathered from literature having different types of construction, different countries, different periods and different numbers of delay causes and delay groups. A questionnaire and personal interviews have formed the basis of this paper listing 293 delay causes. The questionnaire survey was distributed to 500 construction participants and 389 were received who represent consultants, contractors and site/design engineers excluding the owner representing the government in road projects as one party only. Relative Importance Index (RII) is calculated and according to the highest values the top twenty and the least twenty delay causes of construction projects in Egypt are determined. A case study is analyzed and compared to the most important delay causes in the paper. The test results reveal good correlation of causes and groups between contractors and site/design engineers and between consultants and site design engineers and a somewhat low correlation between contractors and consultants. So there are no root causes that can be taking for granted to be most or least effective delay causes. Proposed model for predicting actual road construction project duration was developed, a real case study tested the accuracy of proposed model. According to the analysis of case study, the most contributing causes and groups to delays were discussed, and some future recommendations were proposed in order to control and minimize delays in road construction projects. These findings can be helpful for project managers to mitigate the road construction delays in Egypt. In order to effectively overcome the road construction delays in developing countries, suggestions are made for fundamental and large‐scale reforms in procurement systems and stakeholders’ management. Also, this paper is useful for both researchers and road construction parties and allows detailed and repeatable analysis of the progress of a road construction project in order to facilitate and achieve a competitive level of time, cost and quality for effective road construction projects.
Abstract
Construction delays are a common phenomenon in civil engineering projects in Egypt including road construction projects. Therefore, it is essential to study and analyze causes [...]
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Effect of partial slip on an unsteady MHD mixed convection stagnation-point flow of a micropolar fluid towards a permeable shrinking sheet
. Aurangzaib, K. Bhattacharyya, S. Shafie

Collection of Alexandria Engineering Journal (2017).

Abstract
The objective of the present study was to investigate the partial slip effect on an unsteady two-dimensional mixed convection stagnation point flow towards a permeable shrinking sheet. The governing equations are reduced to a system of non-dimensional partial differential equations using a semi-similarity transformation, before being solved numerically by using Keller-box method. The features of the flow characteristics for different values of the governing parameters are analysed and discussed. The results indicate that the momentum, thermal and concentration boundary layer thicknesses increase with increasing mixed convection parameter for opposing flow, whereas the opposite effect is observed for assisting flow. The results also show that the surface velocity is higher when there is slip at a sheet compared to its absent. Further, the study indicates that the boundary layer thicknesses become thicker and thicker with increasing shrinking parameter, while the opposite effect is observed with increasing Hartmann number. Comparison with previously published work for special cases is performed and found to be in excellent agreement.
Abstract
The objective of the present study was to investigate the partial slip effect on an unsteady two-dimensional mixed convection stagnation point flow towards a permeable shrinking [...]
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Drag on a slip spherical particle moving in a couple stress fluid
E. Ashmawy

Collection of Alexandria Engineering Journal (2017).

Abstract
The creeping motion of a rigid slip sphere in an unbounded couple stress fluid is investigated. The linear slip boundary condition and the vanishing couple stress condition are applied on the surface of the sphere. A simple formula for the drag force acting on a slip sphere translating in an unbounded couple stress fluid is obtained. Special cases of the deduced drag formula are concluded and compared with analogous results in the literature. The normalized drag force experienced by the fluid on the slip sphere is represented graphically and the effects of slip parameter and viscosity coefficients are discussed.
Abstract
The creeping motion of a rigid slip sphere in an unbounded couple stress fluid is investigated. The linear slip boundary condition and the vanishing couple stress condition [...]
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Unequal diffusivities case of homogeneous–heterogeneous reactions within viscoelastic fluid flow in the presence of induced magnetic-field and nonlinear thermal radiation
I. Animasaun, C. Raju, N. Sandeep

Collection of Alexandria Engineering Journal (2017).

Abstract
This article presents the effects of nonlinear thermal radiation and induced magnetic field on viscoelastic fluid flow toward a stagnation point. It is assumed that there exists a kind of chemical reaction between chemical species A and B. The diffusion coefficients of the two chemical species in the viscoelastic fluid flow are unequal. Since chemical species B is a catalyst at the horizontal surface, hence homogeneous and heterogeneous schemes are of the isothermal cubic autocatalytic reaction and first order reaction respectively. The transformed governing equations are solved numerically using Runge–Kutta integration scheme along with Newton’s method. Good agreement is obtained between present and published numerical results for a limiting case. The influence of some pertinent parameters on skin friction coefficient, local heat transfer rate, together with velocity, induced magnetic field, temperature, and concentration profiles is illustrated graphically and discussed. Based on all of these assumptions, results indicate that the effects of induced magnetic and viscoelastic parameters on velocity, transverse velocity and velocity of induced magnetic field are almost the same but opposite in nature. The strength of heterogeneous reaction parameter is very helpful to reduce the concentration of bulk fluid and increase the concentration of catalyst at the surface.
Abstract
This article presents the effects of nonlinear thermal radiation and induced magnetic field on viscoelastic fluid flow toward a stagnation point. It is assumed that there [...]
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MHD flow and heat transfer of couple stress fluid over an oscillatory stretching sheet with heat source/sink in porous medium
N. Ali, S. Khan, M. Sajid, Z. Abbas

Collection of Alexandria Engineering Journal (2017).

Abstract
This article presents the MHD flow and heat transfer of a couple stress fluid over oscillatory stretching sheet embedded in a porous medium in the presence of heat source/sink. The unsteady flow problem is reduced to two coupled partial differential equations using dimensionless variables. Homotopy analysis method is employed to obtain the solution of these equations. Based on the solution of these equations an extensive analysis is performed to investigate the effects of various flow parameters on velocity and temperature fields, skin friction coefficient and Nusselt number. It is found that the presence of couple stress in viscous fluid increases the amplitude of oscillations in velocity and skin friction coefficient. It is also noticed that temperature increases by increasing heat source parameter. Moreover, the numerical values of local Nusselt number are calculated and shown in tabular form. It is found that the Nusselt number increases by increasing Prandtl number while it decreases by increasing couple stress parameter.
Abstract
This article presents the MHD flow and heat transfer of a couple stress fluid over oscillatory stretching sheet embedded in a porous medium in the presence of heat source/sink. [...]
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Unaxisymmetric stagnation-point flow and heat transfer of a viscous fluid with variable viscosity on a cylinder in constant heat flux
R. Alizadeh, A. Rahimi, R. Arjmandzadeh, M. Najafi, A. Alizadeh

Collection of Alexandria Engineering Journal (2017).

Abstract
Existing solutions of the problem of axisymmetric stagnation-point flow and heat transfer on either a cylinder or a flat plate are for incompressible fluid. Here, fluid with viscosity proportional to a linear function of temperature is considered in the problem of an unaxisymmetric stagnation-point flow and heat transfer of an infinite stationary cylinder with non-uniform normal transpiration U0(φ ) and constant heat flux. The impinging free-stream is steady and with a constant strain rate k¯. A reduction of Navier–Stokes and energy equations is obtained by use of appropriate similarity transformations. The semi-similar solution of the Navier–Stokes equations and energy equation has been obtained numerically using an implicit finite-difference scheme. All the solutions aforesaid are presented for Reynolds numbers, Re=k¯a2/2υ∞, ranging from 0.01 to 100 for different values of Prandtl number and viscosity-variation parameter and for selected values of transpiration rate function, S(φ)=U0(φ)/k¯a, where a is cylinder radius and υ∞ is the reference kinematic viscosity of the fluid. Dimensionless shear-stresses corresponding to all the cases increase with the increase in Reynolds number and transpiration rate function while dimensionless shear stresses decrease with the increase in viscosity-variation parameter. The local coefficient of heat transfer (Nusselt number) increases with increasing the transpiration rate function and Prandtl number.
Abstract
Existing solutions of the problem of axisymmetric stagnation-point flow and heat transfer on either a cylinder or a flat plate are for incompressible fluid. Here, fluid with [...]
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Corrosion inhibitory properties of elephant grass (Pennisetum purpureum) extract: Effect on mild steel corrosion in 1 M HCl solution
K. Alaneme, S. Olusegun, A. Alo

Collection of Alexandria Engineering Journal (2017).

Abstract
Corrosion inhibition and adsorption characteristics of elephant grass extracts on mild steel in 1 M HCl solution were investigated. Mass loss, corrosion rate measurements, inhibition efficiency, atomic adsorption spectroscopy (AAS), FT-IR spectroscopy and scanning electron spectroscopic analysis were used to assess the inhibitory properties of the extract in the acid solution. The results show that the steel dissolution rate in the acidic solution was sensitive to the extract concentration as mass loss and corrosion rates were observed to decrease with increase in the extract concentration. The inhibition efficiencies were averagely above 95% at room temperature increasing with increase in concentration of the extract but decreases with increasing temperature. FTIR results showed that the inhibition was essentially by absorption through the functional groups present in the extract while the activation energies and Langmuir adsorption isotherms confirm the mechanism to be physical adsorption. The SEM images of the corroded substrates confirmed pitting as the primary corrosion mechanism which was substantially mitigated with the use of the extract. Overall, the elephant grass extract was found to be efficient for corrosion inhibition of mild steel in HCl environment.
Abstract
Corrosion inhibition and adsorption characteristics of elephant grass extracts on mild steel in 1 M HCl solution were investigated. Mass loss, corrosion rate measurements, [...]
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The general solutions of singular and non-singular matrix fractional time-varying descriptor systems with constant coefficient matrices in Caputo sense
Z. Al-Zhour

Collection of Alexandria Engineering Journal (2017).

Abstract
In this paper, we generalize the time-varying descriptor systems to the case of fractional order in matrix forms. Moreover, we present the general exact solutions of the linear singular and non-singular matrix fractional time-varying descriptor systems with constant coefficient matrices in Caputo sense by using a new attractive method. Finally, two illustrated examples are also given to show our new approach.
Abstract
In this paper, we generalize the time-varying descriptor systems to the case of fractional order in matrix forms. Moreover, we present the general exact solutions of the linear [...]
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Review of magnetohydrodynamic pump applications
O. Al-Habahbeh, M. Al-Saqqa, M. Safi, T. Khater

Collection of Alexandria Engineering Journal (2017).

Abstract
Magneto-hydrodynamic (MHD) principle is an important interdisciplinary field. One of the most important applications of this effect is pumping of materials that are hard to pump using conventional pumps. In this work, the progress achieved in this field is surveyed and organized according to the type of application. The literature of the past 27 years is searched for the major developments of MHD applications. MHD seawater thrusters are promising for a variety of applications requiring high flow rates and velocity. MHD molten metal pump is important replacement to conventional pumps because their moving parts cannot stand the molten metal temperature. MHD molten salt pump is used for nuclear reactor coolants due to its no-moving-parts feature. Nanofluid MHD pumping is a promising technology especially for bioapplications. Advantages of MHD include silence due to no-moving-parts propulsion. Much progress has been made, but with MHD pump still not suitable for wider applications, this remains a fertile area for future research.
Abstract
Magneto-hydrodynamic (MHD) principle is an important interdisciplinary field. One of the most important applications of this effect is pumping of materials that are hard to [...]
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Application of perturbation–iteration method to Lotka–Volterra equations
Y. Aksoy, Ü. Göktaş, M. Pakdemirli, İ. Dolapçı

Collection of Alexandria Engineering Journal (2017).

Abstract
Perturbation–iteration method is generalized for systems of first order differential equations. Approximate solutions of Lotka–Volterra systems are obtained using the method. Comparisons of our results with each other and with numerical solutions are given. The method is implemented in Mathematica, a major computer algebra system. The package PerturbationIteration.m automatically carries out the tedious calculations of the method.
Abstract
Perturbation–iteration method is generalized for systems of first order differential equations. Approximate solutions of Lotka–Volterra systems are obtained using the [...]
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Sustaining the shelf life of fresh food in cold chain – A burden on the environment
O. Adekomaya, T. Jamiru, R. Sadiku, Z. Huan

Collection of Alexandria Engineering Journal (2017).

Abstract
Energy consumption in cold chains has been predicted to rise significantly in view of the increasing world population. Of critical attention is the increasing number of road transport refrigeration which is highly gaining enormous ground globally. In view of the fact that 40% of all foods require refrigeration, 15% of world fossil fuel energy is used in food transport refrigeration. This concern necessitates this study to examine cold chain system with the emphasis on the impact of energy consumption in sustaining the shelf life of fresh food. As the world continues to battle with the global warming occasioned by emission of carbon dioxide from fossil fuel, this study identifies alternative means of saving energy in food transportation system through minimizing energy consumption in diesel engine driven vapour compression system. Preserving perishable fresh food (mainly vegetable) under sub-zero weather is another debacle the authors envisaged in the quest to reduce fossil fuel consumption. This process requires heating the mechanical refrigeration unit in a reverse-cycle to raise the temperature at 0 °C which may further result in more energy demand. The conclusion drawn from this study could be useful in re-designing food transport system for optimal energy saving.
Abstract
Energy consumption in cold chains has been predicted to rise significantly in view of the increasing world population. Of critical attention is the increasing number of road [...]
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The squeezing flow of Cu-water and Cu-kerosene nanofluids between two parallel plates
N. Acharya, K. Das, P. Kundu

Collection of Alexandria Engineering Journal (2017).

Abstract
The present article investigates the squeezing flow of two types of nanofluids such as Cu-water and Cu-kerosene between two parallel plates in the presence of magnetic field. The governing non-linear partial differential equations are transformed into ordinary differential equations by applying suitable similarity transformation and then solved numerically using RK-4 method with shooting technique and analytically using differential transformation method (DTM). The influence of arising relevant parameters on flow characteristics has been discussed through graphs and tables. A comparative study has been taken into account between existing results and present work and it is found to be in excellent harmony.
Abstract
The present article investigates the squeezing flow of two types of nanofluids such as Cu-water and Cu-kerosene between two parallel plates in the presence of magnetic field. [...]
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Temporal and spatial variation of differential code biases: A case study of regional network in Egypt
M. Abid, A. Mousa, M. Rabah, M. mewafi, A. Awad

Collection of Alexandria Engineering Journal (2017).

Abstract
Measurements of Global Positioning Satellite System receivers are affected by systematic offsets related to group and phase delays of the signal generation and processing chain. One of the important factors affecting the ionosphere Total Electron Content estimation accuracy is the hardware differential code biases inherited in both Global Positioning System satellites and receivers. The resulting code and phase biases depend on the transmission frequency and the employed signal modulation. An efficient algorithm using the geometry conditions between satellite and tracking receivers is proposed to determine the receiver differential code biases using Egyptian permanent reference stations. This method does not require a traditional single-layer ionosphere model and can be used for estimating differential code biases of receivers in a regional network. This paper estimates receiver differential code biases for nine receivers located within Egyptian network. The results showed that the estimated mean value of the receiver differential code biases varied from −28 ns (nanosecond) to 39 ns. It is clear from the results that differential code biases values for Egyptian sites do not vary much with latitude and longitude, except at Aswan and Abu Simpel. Differential code biases values increase gradually with increasing height.
Abstract
Measurements of Global Positioning Satellite System receivers are affected by systematic offsets related to group and phase delays of the signal generation and processing [...]
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MHD free convection flow of Eyring–Powell fluid from vertical surface in porous media with Hall/ionslip currents and ohmic dissipation
S. Gaffar, V. Prasad, E. Reddy

Collection of Alexandria Engineering Journal (2017).

Abstract
A mathematical study is presented to analyze the nonlinear, non-isothermal, magnetohydrodynamic (MHD) free convection boundary layer flow, heat and mass transfer of non-Newtonian Eyring–Powell fluid from a vertical surface in a non-Darcy, isotropic, homogenous porous medium, in the presence of Hall currents and ionslip currents. The governing nonlinear coupled partial differential equations for momentum conservation in the x, and z directions, heat and mass conservation, in the flow regime are transformed from an (x, y, z) coordinate system to a (ξ, η) coordinate system in terms of dimensionless x-direction velocity (f′) and z-direction velocity (G), dimensionless temperature and concentration functions (θ and ϕ) under appropriate boundary conditions. Both Darcian and Forchheimer porous impedances are incorporated in both momentum equations. Computations are also provided for the variation of the x and z direction shear stress components and also heat and mass transfer rates. It is observed that with increasing ɛ, primary velocity, secondary velocity, heat and mass transfer rates are decreased whereas, the temperature, concentration and skin friction are increased. An increasing δ is found to increase primary and secondary velocities, skin friction, heat and mass transfer rates. But the temperature and concentration decrease. Increasing βe and βi are seen to increase primary velocity, skin friction, heat and mass transfer rates whereas secondary velocity, temperature and concentration are decreased. Excellent correlation is achieved with a Nakamura tridiagonal finite difference scheme (NTM). The model finds applications in magnetic materials processing, MHD power generators and purification of crude oils.
Abstract
A mathematical study is presented to analyze the nonlinear, non-isothermal, magnetohydrodynamic (MHD) free convection boundary layer flow, heat and mass transfer of non-Newtonian [...]
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Retrospective analysis of the experience with 100 cases of retroperitoneoscopy in Centro Hospitalar do Tâmega e Sousa
P. Valente, F. Vila, H. Castro, R. Borges, A. Oliveira, J. Lindoro

Collection of Acta Urológica Portuguesa (2017).

Abstract
Since the introduction of minimal invasive surgery in the 90s, many international urologic centres have developed retroperitoneoscopy as access way for treatment of multiple urologic pathologies. The aim of this work is to analyze our initial experience in retroperitoneoscopy. Materials and methods: Retrospective analysis of the first 100 cases of retroperitoneoscopy by counsulting the clinical records. These operations were classified according to their technical difficulty and operative risk. Operative complications were stratified into five grades using the modified Clavien classification system (CCS). The first 100 retroperitoneoscopic procedures of our hospital were performed from January 2008 to July 2013 in 51 men and 49 women with a mean age of 52 years old (18‐84 years old). They were comprised of 22 renal cyst marsupialization, 36 Simple Nephrectomies, 4 Radical Nephrectomies, 2 Nephroureterectomies, 14 dismembered pyeloplasties, 1 lumbar ureterolithotomy and 21 Parcial Nephrectomies. Using the classification of surgical complexity European Scoring System for Laparoscopic Operations in Urology modified by Rassweiler in 2006, we classified 22 procedures as simple, 57 procedures as difficult and 21 procedures as very difficult. The mean operation time was 158 minutes (range: 67‐280 minutes). The mean operation time was 96, 157, and 220 minutes in simple, difficult and very difficult procedures, repectively. The open conversion rate was 3%. A total of 12 patients had postoperative complications: CCS Grade I in 4, CCS Grade II in 6 and CCS Grade IIIb in 2 patients. Discussion/Conclusions: The retroperitoneoscopy has proven to be a safe and a versatile access for a minimally invasive treatment of many urologic pathologies.
Abstract
Since the introduction of minimal invasive surgery in the 90s, many international urologic centres have developed retroperitoneoscopy as access way for treatment of multiple [...]
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Metilação do gene MST1R como biomarcador de diagnóstico em tumores de células renais
A. Pires-Luís, F. Lobo, M. Vieira-Coimbra, P. Costa-Pinheiro, L. Antunes, J. Oliveira, R. Henrique, C. Jerónimo

Collection of Acta Urológica Portuguesa (2017).

Abstract
Renal cell tumors comprise both benign – oncocytoma – and malignant – clear cell renal cell carcinoma, papillary renal cell carcinoma, and chromophobe renal cell carcinoma – entities. Since the differential diagnosis among renal cell tumors is sometimes difficult on clinical, imaging and pathological grounds, and prognosis is quite dissimilar, epigenetic-based diagnostic biomarkers, specially promoter methylation, might be useful for accurate diagnosis and therapeutic planning. EpiTect Methyl II PCR Array was used to screen methylation status of 22 genes, involved in epithelial to mesenchymal transition. Quantitative real-time methylation specific polymerase chain reaction was performed for candidate gene validation, and methylation levels of renal cell tumors subtypes and normal kidney were determined and compared. MST1R promoter methylation level was significantly higher in clear cell renal cell carcinoma (median: 5367) compared to other renal cell tumors (median: papillary renal cell carcinoma – 1084, chromophobe renal cell carcinoma – 1023, oncocytoma – 1337) and normal kidney (median: 1125), allowing for accurate discrimination from other renal cell tumors with high sensitivity (>96.7%) and specificity (86.7%). Quantitative MST1R promoter methylation may be useful as biomarker for accurate diagnosis of clear cell renal cell carcinoma in problematic cases.
Abstract
Renal cell tumors comprise both benign – oncocytoma – and malignant – clear cell renal cell carcinoma, papillary renal cell carcinoma, and chromophobe renal cell carcinoma [...]
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Paratesticular adenomatoid tumor: a case report
L. Sepúlveda, P. Moreira, P. Sousa, F. Rodrigues, C. Abrantes, T. Gorgal, L. Sepúlveda, A. Roseiro, M. Freire, P. Moreira, D. Castelo, A. Mota

Collection of Acta Urológica Portuguesa (2017).

Abstract
The adenomatoid tumor is a rare benign neoplasm of mesothelial origin, possible to occur in the genital tract in both sexes. It is commonly paratesticular, mainly in the epididymis. Surgical treatment consists of tumor resection and preservation of the testis whenever possible. We describe a case of a 40 years old man presenting scrotal discomfort, palpable lower pole mass of the right testicle and normal tumor markers. The patient underwent local excision of nodule with right testis preservation, as the neoplasm was unrelated with the albuginea. Subsequent pathology study (with histology and immunohistochemical markers) diagnosed a paratesticular adenomatoid tumor.
Abstract
The adenomatoid tumor is a rare benign neoplasm of mesothelial origin, possible to occur in the genital tract in both sexes. It is commonly paratesticular, mainly in the epididymis. [...]
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Intravesical bacilo de Calmette-Guérin therapy for bladder tumors / what we know so far
J. Santos, N. Rolim, T. Rodrigues, F. Lopes, R. Mota, A. Covita, M. Soares, P. Monteiro, A. Canhoto, R. Nogueira, H. Monteiro

Collection of Acta Urológica Portuguesa (2017).

Abstract
The use of intravesical Bacillus Calmette-Guérin is a valid option in the treatment of non-muscle invasive bladder tumors, making it the main subject of a lot of publications. The aim of the present study is to review and consolidate the data available about this subject. A review of the data available was made on PubMed with the keywords: “intravesical BCG” and “non-muscle invasive bladder cancer”. Original and review articles written in English or Portuguese were selected. We present the discussion alongside the results for structural purposes. Scientific evidence strongly advises in favor of BCG use on intermediate and high risk tumors, due to its impact on the recurrence and possibly on the progression rates. It is important to be watchful for possible local and systemic side effects, that when detected call for a rightful therapeutically decision alongside the recommended schemes. The use of intravesical BCG with therapeutically purposes has strong evidence on the non-muscle invasive bladder tumors. More studies are needed in order to better understand the best administration scheme and its mechanism of action.
Abstract
The use of intravesical Bacillus Calmette-Guérin is a valid option in the treatment of non-muscle invasive bladder tumors, making it the main subject of a lot of publications. [...]
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Effectiveness of penile vibratory stimulation after spinal cord injury
S. Oliveira, A. Azenha, A. Sousa, J. Pinheiro, A. Santos

Collection of Acta Urológica Portuguesa (2017).

Abstract
Spinal cord injury in males is frequently associated with infertility, due to ejaculatory dysfunction and/or semen properties alterations. Penile vibratory stimulation can be used as a semen collecting method. The aim of this work is to disclose the use of this method in spinal cord injured male patients, evaluate its possible complications and clarify if the ejaculated semen is prone to fertilization. Vibratory stimulation was used in three spinal cord injured patients to collect semen and, after that procedure, the evaluation of sperm parameters was performed. Vibratory stimulation was efficient in all the subjects, in the majority of the sessions. The ejaculates present normal sperm concentration, but variable sperm progressive motility and morphology, when comparing with the standard criteria. Penile vibratory stimulation is an efficient procedure to induce ejaculation in spinal cord injured patients. Despite the considerable variability between the subjects, the ejaculates met the required quality to allow fertilization trough assisted reproductive technologies.
Abstract
Spinal cord injury in males is frequently associated with infertility, due to ejaculatory dysfunction and/or semen properties alterations. Penile vibratory stimulation can [...]
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Complications of androgen deprivation therapy in prostate cancer / a review
N. Rolim, F. Lopes, T. Rodrigues, J. Santos, R. Mota, A. Covita, M. Soares, P. Monteiro, A. Canhoto, R. Nogueira, H. Monteiro

Collection of Acta Urológica Portuguesa (2017).

Abstract
Androgen deprivation therapy (ADT) is the standard therapy for advanced prostate cancer. However, it encompasses several adverse effects, with impact on patient’s quality of life and, eventually, on overall survival. This article will review the most important side-effects associated with androgen deprivation therapy and the methods for minimizing their impact.
Abstract
Androgen deprivation therapy (ADT) is the standard therapy for advanced prostate cancer. However, it encompasses several adverse effects, with impact on patient’s quality [...]
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Sparing surgery for testicular tumors
S. Rodrigues, V. Metrogos, M. Dores, J. Marques, M. Rodrigues, M. Cabrita, G. Rosa, A. Coutinho

Collection of Acta Urológica Portuguesa (2017).

Abstract
Malignant germ cell tumors represent the majority of testicular masses, according to current knowledge, radical orchiectomy remains the standard of care in the management of this type of cancer. However, testis‐sparing surgery (TSS) can be an alternative to radical surgery in selected cases, particularly in patients with small testicular masses (STM). The authors conducted a review of the current indications for performing testicular sparing surgery as well as functional and oncological results of it. We conducted a literature search in Medline database (PubMed) using the keywords: “testis sparing surgery”, “partial orchiectomy”, ‘testis tumor’, ‘small testicular mass/tumor’. The search was limited to article in English language, published from 2010 to the current date. randomized controlled trials/studies with high level of evidence that compare TSS with radical orchiectomy were not found. Indications for TSS are still controversial, particularly in patients with normal contralateral testis. The organ sparing surgery seems a viable therapeutic option for patients with small non‐palpable testicular mass (with < 20 mm major axis), bilateral tumors or single testicle. The frozen section examination plays a decisive role in the technique, since it allows the distinction between malignant and benign neoplasms, as well as assessing the status of surgical margins. The medium and long follow‐up results of the analyzed retrospective studies revealed no significant risk of local and/or distant relapses. Regarding the testis, the organ‐sparing surgery can be adopted safely in the treatment of selected cases. Prospective multicentric and high level of evidence studies are needed in order for TSS become a real alternative to radical surgery, as well to evaluate the oncological safety and real functional benefits of preserving the testis.
Abstract
Malignant germ cell tumors represent the majority of testicular masses, according to current knowledge, radical orchiectomy remains the standard of care in the management [...]
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Use of acetylsalicylic acid, metformin and statins and prostate cancer: Impact on the pathological characteristics and risk of biochemical recurrence
S. Rodrigues, M. Dores, V. Metrogos, M. Rodrigues, P. Gomes, M. Cabrita, G. Rosa, A. Coutinho, J. Neves, A. Cordeiro, V. Rodrigues, P. Mota, E. Dias, F. Botelho

Collection of Acta Urológica Portuguesa (2017).

Abstract
The impact of using ASA (acetylsalicylic acid), metformin and statins on the prostate cancer may be significant, but is not clear and findings from previous studies are inconsistent. This study aims to evaluate the relationship between the use of ASA, metformin and statins and the pathological characteristics and risk of biochemical recurrence (BCR) of prostate cancer. A total of 311 patients submitted to radical prostatectomy (RP) at Hospital de Braga between January 2010 and June 2014 were analyzed. Data were obtained from clinical records and the crude and adjusted association between the use of a specific drug and prostate specific antigen (PSA), pathological stage, Gleason score, positive surgical margin and risk of biochemical recurrence were calculated. Overall, 26 (8.4%) of the patients used ASA, 35 (11.3%) metformin and 112 (36%) statins. The ASA users had a lower PSA compared with the non users (5.9 vs. 8.9 ng/m, p = 0.008). Its use was an independent predictor of positive surgical margin (OR = 3.77, IC 95%: 1.45‐9.78). The use of metformin was associated with advanced pathological stages, more precisely pT3b (20% vs. 7.7%, p = 0.048). No other differences were detected between ASA, metformin and statins users. The use of ASA, metformin and statins has no beneficial effect on prostatic cancer patients. On the opposite, an association between the use of metformin and advanced pathological stages was observed. These results should be validated in other larger samples and longer follow‐up. The association between the use of ASA and lower PSA was already detected in other studies, whose mechanism should be clarified in future
Abstract
The impact of using ASA (acetylsalicylic acid), metformin and statins on the prostate cancer may be significant, but is not clear and findings from previous studies are inconsistent. [...]
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Hyperbaric oxygen therapy for radiation‐induced hemorrhagic cystitis
T. Oliveira, A. Romão, P. Oliveira, S. Gaspar, F. Guerreiro, T. Lopes

Collection of Acta Urológica Portuguesa (2017).

Abstract
Due to considerable morbidity and mortality rates, radiation‐induced hemorrhagic cystitis is an important complication of pelvic irradiation. The available conservative treatment techniques show limited results. Hyperbaric oxygen has shown to be effective in the treatment of radiation‐induced lesions, including radiation cystitis. Our aim was to analyze the effectiveness and safety of hyperbaric oxygen therapy for refractory radiation‐induced hemorrhagic cystitis. Clinical records of 176 patients with refractory radiation‐induced hemorrhagic cystitis treated at our centre were retrospectively analyzed. The evolution of macroscopic hematuria was the main therapeutic outcome analyzed. 23, 9% of patients showed other radiation‐induced soft tissue lesions. After an average of 37 sessions of hyperbaric oxygen, 89, 8% of patients showed resolution of hematuria. Adverse events were reported in 1, 7% of patients. Hyperbaric oxygen was a safe and effective therapy for radiation‐induced hemorrhagic cystitis. Concomitant radiation‐induced soft tissue lesions were relatively frequent, which makes hyperbaric oxygen an excellent choice as first line treatment in those patients.
Abstract
Due to considerable morbidity and mortality rates, radiation‐induced hemorrhagic cystitis is an important complication of pelvic irradiation. The available conservative [...]
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Considerations in the treatment of Peyronie disease
A. Pimenta, A. Camelo

Collection of Acta Urológica Portuguesa (2017).
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Augmentation Cystoplasty using modified Studers Orthotopic Ileal Neobladder tecnhique
R. Silva, J. Reis, T. Lopes

Collection of Acta Urológica Portuguesa (2017).

Abstract
Although exceedingly rare in developed countries nowadays, we still come across some devastating sequels of genitourinary tuberculosis, requiring careful medical evaluation and expertise on surgical reconstruction. A 58‐year‐old man, previously submitted to a right nephrectomy, developed a life‐threatening episode of urosepsis, leading to the need of a percutaneous nephrostomy due to a long stricture of the terminal ureter of the remaining left kidney. The patient had also developed very severe urinary frequency related to an extremely crippled bladder, with a capacity under 20 mL. After medical treatment of the tuberculosis, an augmentation cystoplasty was performed but in a patient‐tailored way, using an ileal neobladder constructed following the Studer technique that was anastomosed to the remaining bladder tissue with implantation of the healthy segment of the shortened ureter on the afferent limb of the reservoir. The normalisation of bladder capacity (over 250 mL), with preserved filling sensation allowed an excellent patient adaptation. The combination of a severely decreased bladder capacity with a stenosis of the terminal ureter of a single kidney led to a need of a great capacity reservoir as well as a reimplantation of a shortened ureter. The use of an orthotopic ileal neobladder as a large ileocystoplasty patch was the solution adopted.
Abstract
Although exceedingly rare in developed countries nowadays, we still come across some devastating sequels of genitourinary tuberculosis, requiring careful medical evaluation [...]
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Relação entre a qualidade seminal e o equilíbrio oxidativo nos espermatozoides
A. Patricio, D. Cruz, J. Silva, A. Padrão, B. Correia, L. Korrodi-Gregório, R. Ferreira, N. Maia, S. Almeida, J. Lourenço, V. Silva, M. Fardilha

Collection of Acta Urológica Portuguesa (2017).

Abstract
Infertility is a clinical disorder affecting approximately 15% of reproductive-aged couples worldwide. Recently, the influence of oxidative stress (OS) in decreased semen quality has been discussed. OS corresponds to an imbalance between oxidants and antioxidants defenses, present in the organism. High levels of reactive oxygen species (ROS) damage biomolecules present in sperm cells and may lead to the loss of membrane integrity, DNA fragmentation or even to death by apoptosis. This study aimed to evaluate the correlation between human semen clinic parameters and parameters that assessed the presence of OS. A total of 32 semen samples, obtained from a randomized group of donors, were included in this study. Basic semen parameters were analyzed according to the WHOs guidelines. The total antioxidant capacity of sperm cells was measured as well as the expression of certain antioxidant proteins, namely superoxide dismutase (SOD) and glutathione peroxidase 4 (GPx4), by colorimetric techniques and immunoblotting, respectively. The effect of ROS in spermatozoa protein oxidation was analyzed by determining the presence of 3-nitrotyrosine and carbonyl groups, by slot blot. Lipid peroxidation was evaluated, by performing the thiobarbituric acid reactive substances (TBARS) assay with colorimetric tests. The results indicated that SOD was negatively correlated with viscosity (p = 0.035), volume (p = 0.004) and carbonyl groups presence (p = 0.005). This protein also showed a positive correlation with the presence of tail defects in sperm cells (p = 0.044). In turn, GPx4 showed a negative correlation with the presence of non-progressive motile spermatozoa (p = 0.012). TBARS assay revealed a negative correlation with the concentration of sperm cells (p = 0.000) and the total number of spermatozoa (p = 0.026), but, in turn, this assay showed a positive correlation with the volume of semen (p = 0.038). It was concluded that the seminal quality is affected by the oxidative balance in sperm cells. The obtained results suggest that lipid peroxidation leads to a reduction in sperm concentration, antioxidant proteins protect the spermatozoa against protein oxidation and contribute to an increased sperm motility and normal semen viscosity. Thus, evaluation of oxidative parameters may be a useful tool for male infertility diagnosis and follow-up of antioxidant treatments.
Abstract
Infertility is a clinical disorder affecting approximately 15% of reproductive-aged couples worldwide. Recently, the influence of oxidative stress (OS) in decreased semen [...]
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Microsurgical vasovasostomy: our experience
V. Oliveira, R. Amorim, P. Espiridião, J. Dias, L. Xambre, L. Ferraz

Collection of Acta Urológica Portuguesa (2017).

Abstract
To describe the initial experience of CHVNG/E in microsurgical vasovasostomy. The two‐layer technique was applied under microscope magnification in every patient by the same surgeon. 8 bilateral vasovasostomies were performed for vasectomy reversal between 2008 and 2014 at our unit. All the patients were available for follow‐up, with a mean follow‐up time of 6 months. Mean patient age was 38.8 ± 8.7 years and the interval between vasectomy and recanalization of 6 ± 1.5 years. Overall spermatozoid patency rate was 100%, with mobile spermatozoa in the ejaculate of all patients (median 12 x 106 /mL, interquartile interval [7 x 106 /mL‐21 x 106 /mL]). Four of the 8 patients fathered after the procedure. Our results were comparable to the ones described in the literature, confirming the performance of a good surgical technique. Microsurgical vasovasostomy constitutes a very safe method of vasectomy reversal, enabling couples to obtain pregnancies without additional medical treatment. To our knowledge, this is the first group of patients treated by this method in Portugal.
Abstract
To describe the initial experience of CHVNG/E in microsurgical vasovasostomy. The two‐layer technique was applied under microscope magnification in every patient by the [...]
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Ureteral reimplantation in urinary diversions: its the laparoscopy an option?
P. Mota, E. Carvalho‐Dias, N. Carvalho, A. Cordeiro, J. Torres, N. Morais, G. Grimaldi, C. Oliveira, A. Carvalho, E. Lima

Collection of Acta Urológica Portuguesa (2017).

Abstract
The ureterointestinal stenosis is a relatively frequent complication after urinary diversions. The laparoscopic approach is rarely used but stay a therapeutic option. Show the surgical technique, step by step, of the laparoscopic ureteral/ureterointestinal estenosis correction. A vídeo of a distal ureteral stenosis laparoscopic correction, on a patient that undergone laparoscopic radical cystectomy with orthotopic neobladder confection, was presented. It was possible the laparoscopic correction of a distal right ureter estenosis with good results and no complications. The laparoscopic approach proved effective for treating ureter/ureterointestinal anastomosis stenosis and should be taken as a good option of treatment.
Abstract
The ureterointestinal stenosis is a relatively frequent complication after urinary diversions. The laparoscopic approach is rarely used but stay a therapeutic option. Show [...]
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Nephrogenic adenoma of the urinary bladder: A case report and review of the literature
P. Baltazar, A. Meirinha, R. João, J. Pina, H. Pinheiro, J. Forte, M. Mafra, L. Pinheiro

Collection of Acta Urológica Portuguesa (2017).

Abstract
Nephrogenic adenoma of the urinary bladder (NAB) is a rare and benign urothelial tumor. The existing literature is scarce regarding its etiology, clinical symptoms and therapeutic options. This paper presents the first reported case of a patient with HIV‐1 infection to whom an NAB was diagnosed. We report a case of a female patient of 49 years old, seropositive for HIV‐1, with pollakiuria, mictional urgency, feeling of incomplete bladder emptying and intermittent macroscopic hematuria. The patient was submitted to TURB of a suspected intravesical lesion. Histopathological examination of the resected material was consistent with an NAB. The patient is in follow‐up, having completed one year with no sign of lesion recurrence. NAB is a metaplastic lesion of the urothelial tissue. Its etiology is not fully understood. NAB is associated with chronic inflammatory processes or to a state of immunosuppression. Its diagnosis is histological, characterized by the presence of tubular structures similar to renal tubules. This work is particularly relevant because it is the first described case of NAB in a patient immunodepressed by HIV‐1 infection.
Abstract
Nephrogenic adenoma of the urinary bladder (NAB) is a rare and benign urothelial tumor. The existing literature is scarce regarding its etiology, clinical symptoms and therapeutic [...]
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Mais um passo a caminho do objectivo - a excelência
C. Silva, A. Figueiredo

Collection of Acta Urológica Portuguesa (2017).
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Efficacy of botulinum toxin type A in the treatment of neurogenic lower urinary tract disfunction due to spinal cord injury
C. Marialva, M. Bettencourt, P. Vale, J. Bastos, M. Carvalho, F. Faria, N. Menezes

Collection of Acta Urológica Portuguesa (2017).

Abstract
The prevalence of neurogenic lower urinary tract disfunction (NLUTD) is unknown, but the risk of developing NLUTD associated with spinal cord injury (SCI) is high. Verify the changes of intradetrusor BTX‐A injection on urodynamic parameters and in the QoL of NLUTD patients due to SCI. Retrospective study of 38 patients with SCI submitted to BTX‐A injection in our departments. Urodinamic studies were performed before and 3 to 6 months after treatment. QoL was evaluated by the Qualiveen questionnaire applied to 20 patients. Statistical analysis was performed with correlation tests for paired samples. Mean age was 38 years (Min = 23, Máx = 63), with 63.2% of males. The most frequent level of SCI was thoracic (52.6%). The average period between the SCI and the first treatment was 92 months (15 to 240 months). The patients had a mean of 3 treatments (min = 1, máx = 8), with 3 episodes of side effects ‐ transient and mild hypoasthenia. We collected data of urodynamic studies in 35 patients that showed increase in bladder capacity (p = 0, 24) and compliance (p < 0, 01) as well as a reduction in Pdetmax (p < 0.01). 20 patients answered the Qualiveen questionnaire with a mean result of 1 (possible final score 0‐4) The use of BTX‐A in our NLUTD patients is a treatment option with very good outcomes and important improvements in urodynamic parameters and in patients quality of life.
Abstract
The prevalence of neurogenic lower urinary tract disfunction (NLUTD) is unknown, but the risk of developing NLUTD associated with spinal cord injury (SCI) is high. Verify [...]
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Cognitive Fusion targeted Prostate Biopsy after Multiparametric Magnetic Resonance Imaging. Comparison with traditional Randomized Biopsy
R. Lucas, P. Baltazar, J. Dias, R. João, L. Pinheiro, H. Pinheiro, A. Meirinha, F. Fernandes, J. Pina

Collection of Acta Urológica Portuguesa (2017).

Abstract
Multiparametric Magnetic Resonance Imaging of the prostate (Mp‐MRI) allows the detection, localization and characterization of suspicious lesions for prostate cancer (PCa). When done prior to the diagnosis it also allows targeting of the biopsy, significantly improving the performance of the standard random prostate biopsy. Our goal is to compare a targeted biopsy technique (cognitive fusion) with the standard double sextant randomized prostate biopsy, and to determine which has better accuracy in the detection of cinically significant prostate cancer. 30 patients aged 61‐67 were selected with a PSA greater than 4 ng/mL (PSA between 5.6 – 19.2) and with suspicious PCa lesions on Mp‐MRI (Pi‐RADS 3‐5). A total of 75 suspicious lesions were detected. All biopsies were performed by the same Urologist (JMP), using trans‐rectal ultrasound guidance and after previous visualization of MRI images. Sampling was targeted to the area considered suspicious on MRI, using a Cognitive Fusion Technique, collecting two samples per area. After that, a double‐sextant standard prostate biopsy was also done in all patients. The variables used for statistical analysis were PCa detection rate and amount of cancer per sample. 22 patients were diagnosed with PCa. In 5 patients, cancer was only detected on targeted cores. Targeted biopsies diagnosed 17% more PCa when compared to random biopsies, and almost doubled the amount of cancer per sample. The overall PCa detection rate was 61% for all samples. 360 fragments were collected from standard randomized prostate biopsy, of which 169 were positive for PCa (47%), with a median Gleason score of 6 (3+3). The average amount of cancer per sample was 25% (5%‐85%). 105 of 150 fragments collected by cognitive fusion targeted biopsies were positive for PCa (70%). The median Gleason score was 7(3+4) with a median amount of cancer per sample of 45% (10%‐90%). Multiparametric prostatic MRI detects areas highly suspicious for PCa, allowing targeted biopsies, which increases diagnostic accuracy and improves the detection of clinically significant PCa.
Abstract
Multiparametric Magnetic Resonance Imaging of the prostate (Mp‐MRI) allows the detection, localization and characterization of suspicious lesions for prostate cancer (PCa). [...]
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A utilidade da quantificação do coeficiente aparente de difusão na estratificação de risco do cancro da próstata por ressonância magnética em 1,5 T sem sonda endorretal
J. Dias, J. Pina, N. Costa, S. Carmo, C. Leal, T. Bilhim, R. Marques, L. Pinheiro

Collection of Acta Urológica Portuguesa (2017).

Abstract
To evaluate the relationship between mean apparent diffusion coefficient (ADC) and post-surgical Gleason scores. To determine the diagnostic accuracy of multiparametric magnetic resonance imaging (mp-MRI) on a 1.5 T magnet in distinguishing low, intermediate and high-grade prostate tumors. This is a retrospective institutional-review-board-approved, single-center study including 30 patients (median age, 60 years) who underwent mp-MRI before prostatectomy for prostate cancer. Using histological reports for guidance, the tumors were localized in ADC maps, and mean ADCs were measured and examined for correlation with Gleason scores. 2 patients had 2 measurable foci, so a total of 32 tumors were studied. The diagnostic accuracy of the mean ADC was assessed by using the area under the receiver operating characteristic curve (ROC). In the differentiation of tumors with a Gleason score of 6 from those with a Gleason score of at least 7, mean ADC yielded an AUC of 0.76 (95% confidence interval: 0.59, 0.93). In the differentiation of tumors with Gleason scores of 6 or 7 from those with a Gleason score of at least 8, mean ADC yielded an AUC of 0.94 (95% confidence interval: 0.86, 1.00). Mean ADC values may allow a correct assessment of the patient risk using a 1.5 T magnet without ERC.
Abstract
To evaluate the relationship between mean apparent diffusion coefficient (ADC) and post-surgical Gleason scores. To determine the diagnostic accuracy of multiparametric magnetic [...]
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18F‐Fluorocholine PET/CT in prostate cancer initial staging
P. Lapa, R. Silva, T. Saraiva, A. Figueiredo, R. Ferreira, G. Costa, J. Lima

Collection of Acta Urológica Portuguesa (2017).

Abstract
In the evaluation of prostate cancer, clinical nomograms are commonly used to predict the probability of lymphatic and extra‐nodal spread. Those nomograms may suggest the presence and the extension of this cancer but do not allow a clear distinction between loco‐regional and distant disease. In this study, it was intended to evaluate the usefulness of 18F‐Fluorocoline positron emission tomography/computed tomography (18F‐FCH‐PET/CT) in the workup of patients with the initial diagnosis of prostate cancer and staged by this imaging technique. The medical records of 39 patients with prostate cancer who underwent 18F‐FCH PET/CT for initial staging, between November 2010 and April 2015, were reviewed. Of these, 20 patients were excluded because they had already started hormonotherapy. In the other 19 patients, the performance of 18F‐FCH PET/CT for the detection of lymph node metastasis was evaluated by calculating the sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy. Six patients had performed pelvic lymphadenectomy (total of 69 lymph nodes), allowing histological confirmation. When there was no histological confirmation (total of 30 lymph nodes and 3 cases of bone metastasis), the findings of 18F‐FCH PET/CT were correlated with the values of PSA and the information from multiple imaging modalities such as CT, bone scan, magnetic resonance (MRI), 18F‐Sodium Fluoride (18F‐NaF) PET/CT of control. The sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy for lymph node metastasis detection were, respectively, 96.8%, 80.9%, 69.8%, 98.2% and 85.8%. In our sample, this technique also allowed the identification of nodal extra pelvic or bone metastasis in 5 patients (26.3%) with implications in the treatment. It showed uptake suggestive of bone metastasis, corroborated by other diagnostic technics or by the follow‐up, in 3 patients, those with prostate specific antigen (PSA) of 9.5 ± 2.9 ng/mL. 18F‐FCH PET/CT is an entire body and multi organ imaging modality that allows the identification, globally, of the sites of disease in patients with prostate cancer. In this study, 18F‐FCH PET/CT showed good results when used in the initial staging of these patients. It is highlighted the ability to detect distant disease, in particular bone metastasis, even with PSA< 20 ng/mL.
Abstract
In the evaluation of prostate cancer, clinical nomograms are commonly used to predict the probability of lymphatic and extra‐nodal spread. Those nomograms may suggest the [...]
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Ureteropelvic junction obstruction caused by Fibroepithelial polyps in children
M. Knoblich, V. Vital, D. Cardoso, F. Alves, F. Mota, P. Casella

Collection of Acta Urológica Portuguesa (2017).

Abstract
Fibroepithelial polyps are extremely rare benign tumors arising from mesodermal tissue in the ureteral wall in children, that can cause ureteropelvic junction obstruction. In this report, we present an 11‐year‐old boy complaining of left intermitent lumbar pain related with ipsilateral hydronephrosis. Surgical exploration revealed several endoluminal polyps located at the ureteropelvic junction, obstructing the lumen of the ureter. Standard treatment consists in resection of the affected ureteral segment followed by open or laparoscopic dismembered pyeloplasty. The prognosis is excellent.
Abstract
Fibroepithelial polyps are extremely rare benign tumors arising from mesodermal tissue in the ureteral wall in children, that can cause ureteropelvic junction obstruction. [...]
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Adenocarcinoma do úraco – metástase atípica de um tumor raro
R. João, M. Almeida, H. Pinheiro, P. Baltazar, J. Neta, J. Nunes, A. Meirinha, R. Farinha, J. Pina, L. Pinheiro

Collection of Acta Urológica Portuguesa (2017).

Abstract
We present the clinical case of a 74-year-old woman with an urachal tumor diagnosed in 2004. The patient underwent a partial cystectomy of the dome with remotion of the urachal remnant and the umbilicus. She had been clinical well until 2011 when she had a kidney metastasis from the urachal tumor. Urachal tumors are very rare, comprising 0.17-0.34% of all bladder cancers. The most common sites of distant metastases are: lung, lymph nodes, bone, intestine, brain, liver, peritoneum, skin and spine. We describe an extremely rare case of a renal metastasis from an urachal cancer, seven years after the initial diagnosis. Usually, patients with localized disease have a good prognosis when treated with surgery. The prognosis gets worse for patients with metastases or local recurrence because a standard chemotherapy regimen does not exist.
Abstract
We present the clinical case of a 74-year-old woman with an urachal tumor diagnosed in 2004. The patient underwent a partial cystectomy of the dome with remotion of the urachal [...]
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Renal oncocytoma – an incidentaloma
V. Guedes, R. Rocha, D. Moura

Collection of Acta Urológica Portuguesa (2017).

Abstract
Renal oncocytoma account for 3 to 7% of primary renal tumors. It is usually diagnosed incidentally and typically has a benign behavior. No currently used imaging techniques can reliably distinguish it from malignant lesions. Similarly, the microscopic diagnosis of oncocytoma remains a challenge. We present a case of an asymptomatic elderly, hypertensive, diabetic and with moderate chronic renal insufficiency, who underwent radical nephrectomy for a solid exophytic lesion of 4.7 cm in the renal pole, detected accidentally. Pathological examination revealed a renal oncocytoma. In this situation, partial nephrectomy would be the preferred surgical treatment, avoiding the long‐term risk of living with a single kidney. The lack of diagnostic tools that reliably differentiate between benign and malignant lesions makes this an important area of study, in order to reduce the number of surgical interventions and the associated morbidity.
Abstract
Renal oncocytoma account for 3 to 7% of primary renal tumors. It is usually diagnosed incidentally and typically has a benign behavior. No currently used imaging techniques [...]
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Pollakiuria and imperforate hymen with hematocolpometra
L. Guedes-Martins, D. Leite, J. Saraiva, B. Candoso

Collection of Acta Urológica Portuguesa (2017).

Abstract
Introduction : Imperforate hymen occurs in approximately 1 in 1, 000 females. It can be found incidentally on physical examination, it is treatable and does not cause significant morbidity. If it is not screened for and treated early, patients present at menarche with a history of cyclical pelvic or abdominal pain and symptoms of urinary retention due to hematocolpos. Case presentation : A 12-year-old premenarchal girl presented to the emergency department with cyclical hypogastric abdominal pain and pollakiuria, with 6 months-evolution. Her medical history was unremarkable, she had never been menstruated or sexually active. She took no medications. Examination of the perineum revealed an imperforate hymen protruding from the introitus. A Y incision was made on the imperforate hymen and during hymenectomy 500mL of brown blood (viscous chocolate colored) was drained from the vagina. She was discharged on postoperative day 2. At the follow-up visit (52nd postoperative day), the patient reported her symptoms had resolved. Conclusion : Although rare, imperforate hymen with retrograde menstruation can cause dilatation of the vagina and uterus (i.e., hematocolpometra). It is an important differential diagnosis of abdominal pain in premenarchal girls often associated with urinary symptoms. It is easily diagnosed by physical examination. © 2014 Associação Portuguesa de Urologia. Published by Elsevier España, S.L.U. All rights reserved.
Abstract
Introduction : Imperforate hymen occurs in approximately 1 in 1, 000 females. It can be found incidentally on physical examination, it is treatable and does not cause significant [...]
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Mecanismos de infertilidade masculina na doença renal poliquística autossómica dominante
V. Grenha, B. Pereira, E. Retroz, H. Coelho, R. Godinho, P. Temido, A. Mota

Collection of Acta Urológica Portuguesa (2017).
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Native tissue repairs in vaginal prolapse surgery – A 5‐year case series
P. Goulart, A. Regalo, L. Canelas, A. Teixeira, Á. Vieira, V. Gonçalves

Collection of Acta Urológica Portuguesa (2017).

Abstract
Currently, the use of mesh in surgery for pelvic organ prolapse has increased, mainly due to the high anatomic failure rate of native tissues repair. The objectives of this study were to analyze the results obtained in the surgical treatment of anterior and posterior defects with native tissues and assess the success rate. Retrospective study of 418 vaginal surgeries to repair defects in the anterior and posterior compartments using native tissues, performed in the Department of Urogynecology, from January 2008 to December 2012. In our sample, mean age was 64 years, with 90% of patients in menopause. 48.1% of women was hysterectomized, 78.2% were submitted to anterior colporrhaphy and 72.7% to posterior colporrhaphy. The correction of anterior paravaginal defect occurred in 32.5% of the surgeries and the posterior in 25.4%. Enterocele was repaired in 68.1% of cases. The intra‐operative and postoperative complications rate was 5%. Of the 347 patients evaluated in the postoperative period, 91.6% was discharged. Seven were later readmitted (2.2%). 29 women were kept in surveillance, mostly for recurrent prolapse, which worsened after a year of follow‐up. A total of 18 women was re‐operated, 13 for recurrence (3.7%). Therefore, the anatomic success rate was 80%. After adding the asymptomatic cases, in which anatomic cure was not achieve, the rate rose to 94%. The compartment defects correction rate of success, in our department, is in accordance with that described in the literature, with lower rates of complications and re‐interventions.
Abstract
Currently, the use of mesh in surgery for pelvic organ prolapse has increased, mainly due to the high anatomic failure rate of native tissues repair. The objectives of this [...]
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Urological outpatient surgery / Oporto’s hospital centre reality and assessment of grade of satisfaction
D. Gil-Sousa, D. Oliveira-Reis, F. Coutinho, J. Soares, L. Osório, S. Ribeiro, A. Fraga

Collection of Acta Urológica Portuguesa (2017).

Abstract
The new Integrated Outpatient Surgery Centre (CICA) of Oporto’s Hospital Centre (CHP), opened in March/2011, developed around a paradigm of innovation and accurate protocols. Analysis of complications and Grade of satisfaction (Grade 1-5) of patients operated by Urology in the first 2 years of CICA, and their correlation through the χ2 test. 550 patients operated between March/2011 and April/2013, predominantly male (96.4%), mean age 43.5 years and anesthetic risk (ASA Average) 1.7. Main pathologies addressed: phimosis (34.0 %), hydrocele (22.7 %), varicocele (10.0%), and isolated short frenulum (6.9%). Mean surgical time 31.71 ± 14.32 min. Rate of early complications (< 28 days) was 4.9% and late complications (≥ 28 days) was 1.3%, with a median time between surgery and complication 8.5 days. 371 patients (67.5 % of the population) answered the telephone interview, presenting Satisfied and Very Satisfied (Grade 4 and 5, respectively) in 94.3% of the cases with surgery and 98.4% with the outpatient conditions and regime. Correlation between the presence of complications (early and late) and Grade of Satisfaction (Grade < 4 Vs. ≥ 4), showed a statistically significant (p
Abstract
The new Integrated Outpatient Surgery Centre (CICA) of Oporto’s Hospital Centre (CHP), opened in March/2011, developed around a paradigm of innovation and accurate protocols. [...]
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Adenocarcinoma incidental da próstata em doentes submetidos a cistoprostatectomia radical / um estudo retrospectivo
S. Gaspar, A. Nunes, T. Oliveira, J. Dias, T. Lopes

Collection of Acta Urológica Portuguesa (2017).

Abstract
Bladder cancer is responsible for 90-95% of urotelial carcinoma. Prostate Cancer is the most prevalent visceral tumor for males and one of the main oncological death causes. The presence of both tumours in the same individual is considered common. Radical cystoprostatectomy with lymphadenectomy and urinary diversion is the gold standard treatment for muscle-invasive bladder cancer. Incidental prostate cancer is described as being present in about 37.9% of cystoprostatectomy patients. To demonstrate the presence of incidental prostate cancer in cystoprostatectomy patients at our department. Clinical data concerning 72 men, from 2008 to 2013, at our institution were retrospectively reviewed. There was incidental prostate cancer in 19.4% of patients, being more frequent in patients older than 70 years of age. Lesions detected were small and circumscribed to the prostate. Four patients (5.6%) had clinically significant prostate cancer: one with a Gleason 7 (3 + 4), pT3b, one with a Gleason 7 (3 + 4), pT2c, one with a Gleason 7 (3 + 4), pT2a, and finally one with a Gleason 6 (3 + 3), with a positive surgical (urethral) margin. The most common histological pattern was Gleason 6 (3 + 3) (78.6%). pT2b predominated in 7 patients (9, 7%). There were equally 4.17% of patients with a pT2a and pT2c (3 patients each). Tumoral volume was inferior to 0.5 cc in 78.6% (11 patients) and superior/ equal to 0.5 cc in 22.4% (3 patients). There was only one patient with a biochemical relapse after 7 months of follow-up, initiating hormonal therapy at that time. Incidental prostate cancer rate was close to the one reported in the literature, being very variable, depending on the definition, the type of histopathological analysis, as the particular methodology of the study. Significative incidental prostate cancer was rare, requiring a closer follow-up with direct implications on the patient’s outcome. Standard pre-operatory evaluation is insufficient to determine precisely which tumours are eligible to this category. Adjuvant treatment for these tumours following cystoprostatectomy has been the same as if it were a prostate cancer following radical prostatectomy surgery. A common carcinogenesis pathway has been proposed and is currently being investigated. Prostate sparing cystectomy may occur in very selected individuals with a known oncological risk for disease progression with questionable functional benefits.
Abstract
Bladder cancer is responsible for 90-95% of urotelial carcinoma. Prostate Cancer is the most prevalent visceral tumor for males and one of the main oncological death causes. [...]
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Training of Urology residents in laparoscopy - Comparison between Portugal and the rest of Europe
F. Furriel, A. Figueiredo, P. Nunes, L. Marconi, P. Dinis, G. Gomes, V. Dias, A. Mota

Collection of Acta Urológica Portuguesa (2017).

Abstract
''Objectives'' : To evaluate the exposure of Portuguese Urology residents (IP) to urological laparoscopy and to its training methods, comparing with the remaining Urology residents in Europe (IE). ''Materials and methods'' : A survey consisting of 23 questions concerning laparoscopic training, which was published online as well as distributed on paper, during the Annual European. Association of Urology Congress in 2012. Data was analysed with descriptive statistics, student t, Mann-Whitney and χ2 tests. ''Results'' : We obtained 219 valid responses, 53 (24.2%) of which from IP. Conventional laparoscopy is equally available for both groups (78.8% of IP vs 72.0% of IE, p = NS). IP have greater access to single port laparoscopy (22.6% vs 8.4%, p < 0.05), but lesser exposure to robot-assisted laparoscopy (0% vs 21.9%, p < 0.01) in their training departments. Performance of conventional laparoscopy as first surgeons was reported by 32.7% of IP and 24.8% of IE (p = NS). The most commonly performed procedure was total nephrectomy (38.4% of IP and 28.8% of IE, p = NS). The majority in both groups considered their laparoscopic experience at the moment of the survey to be “Poor” or worse (81.9% of IP e 75.5% of IE, p = NS). However, IP had greater expectations than IE of improvement during residency (p = 0.01). No previous attendance to laparoscopic courses or fellowships was seen in 35.7% of IP and 41.7% of IE (p = NS). However, IP attended more national courses than IE. “Pelvitrainer” is the most commonly available laboratory training method, (30.2% of IP and 33.3% of IE, p = NS), but 41.9% of IP and 42.4% IE do not have access to any laparoscopic training device. Most residents (84.1% of IP and 74.4% of IE, p = NS) rate their motivation to perform laparoscopy in the future as “High” or “Very High”, and plan performing a post-residency fellowship in this field. ''Conclusions'' : The access to conventional laparoscopy is similar between IP and IE, and both take an active part in this technique. A significant proportion has some experience as laparoscopic surgeons. Despite the relative scarcity of training devices in both groups, IP attend more national courses in laparoscopy, and experience a better sense of evolution during residency than IE. © 2014 Associação Portuguesa de Urologia. Published by Elsevier España, S.L.U. All rights reserved.
Abstract
''Objectives'' : To evaluate the exposure of Portuguese Urology residents (IP) to urological laparoscopy and to its training methods, comparing with the remaining Urology [...]
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Uso de estatinas e níveis séricos do antigénio específico da próstata
A. Ferro, F. Pina, M. Severo, P. Dias, F. Botelho, N. Lunet

Collection of Acta Urológica Portuguesa (2017).

Abstract
To quantify the effect of statins’ use on Prostate Specific Antigen (PSA) levels in patients referred to prostate biopsy and to determinate if the exposure to statins must be considered to improve the prostate cancer diagnostic accuracy of PSA. We selected 551 subjects with PSA
Abstract
To quantify the effect of statins’ use on Prostate Specific Antigen (PSA) levels in patients referred to prostate biopsy and to determinate if the exposure to statins must [...]
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Laparoscopic resection of a retroperitoneal schwannoma: a case report and review of the literature
C. Ferreira, F. Reis, T. Correia, M. Cerqueira, L. Carvalho, J. Castro, J. Macedo‐Dias, R. Prisco

Collection of Acta Urológica Portuguesa (2017).

Abstract
Retroperitoneal schwannomas are rare, usually benign tumours that originate in the peripheral neural sheath. Preoperative diagnosis is often impossible. Few cases of laparoscopic removal of retroperitoneal schwannoma have been reported to date. We aim to report a case of retroperitoneal schwannoma using laparoscopic surgical technique. A 61‐year‐old man was found incidentally a solid retroperitoneal tumour by ultrasound. Abdominal computed tomography and magnetic ressonance imaging revealed a well‐defined, heterogeneous tumour, 3 cm in diameter, in pararrenal space close to psoas major. A transperitoneal laparoscopic resection was performed. Operative time was 65 minutes. The patient had an uneventful perioperative course. Histopathological exam revealed a benign schwannoma. No recurrence was detected after 2 years of follow‐up. Preoperative establishment of diagnosis is difficult in case of retroperitoneal schwannomas even with imagiologic or biopsy studies. Complete resection is the diagnosis and treatment of choice. Laparoscopic treatment is minimal invasive, safe and feasible for retroperitoneal schwannomas mainly because these lesions are well limited and hypovascular, allowing a careful dissection from adjacent structures through an improved visualization.
Abstract
Retroperitoneal schwannomas are rare, usually benign tumours that originate in the peripheral neural sheath. Preoperative diagnosis is often impossible. Few cases of laparoscopic [...]
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AMS 800 artificial urinary sphincter - retrospective analysis of six years
P. Dias, D. Costa, N. Tomada, M. Guimarães, F. Cruz

Collection of Acta Urológica Portuguesa (2017).

Abstract
Introduction : The artificial urinary sphincter (AUS) is the gold standard for surgical treatment of male stress urinary incontinence. Objective : Evaluate the results of the artificial urinary sphincter placement of AMS 800 in the Department of Urology of São João Hospital Center in a 6-year period (January 2007/December 2012). Material and methods : 30 male patients with urinary incontinence (UI) underwent placement of AUS AMS 800 through penoscrotal approach, with an average age of 69 years. 25 patients had severe incontinence and 5 moderate. With regard to etiology, UI secondary to radical prostatectomy (RP) in 26 patients, mixed incontinence (detrusor overactivity and PR) in 1 patient, prostatectomy for BPH in 1 patient, neurogenic UI in 2. 9 patients have a prior history of unsuccessful sling Invance, 14 a prior history of external pelvic radiotherapy and 8 a prior history of internal urethrotomy for stricture of vesico-urethral anastomosis. The mean postoperative follow-up was 22.1 months. Mean pads/day before surgery: 5.73. Results : 20 patients (67%) are fully continent (no protection), 5 patients (17%) partially improved or continents (1-2 pads per day or reduction of > 50% of the number of pads), 5 patients (17%) without improvement (≥ 3 pads/day). Adding cured and improved patients, we obtain an overall success rate of approximately 84%. The variation of pads/day before and after surgery (respectively 5.7 and 0.8) is statistically significant (p < 0.05 - Wilcoxon test). Prior history of urethral sling, adjuvant pelvic radiotherapy and anastomotic VU stricture previously treated by urethrotomy do not compromise the continence rates. Regarding complications, mechanical failure occurred in one case (3%), infection in 3 (10%) and urethral erosion also in 3 (10%). The rate of re-operation (revision or removal of the AUS) was 23%. Conclusions : The AUS is an effective treatment for moderate to severe male stress urinary incontinence. Our success rates and complications are consistent with the literature. It has relevant success rate in peculiar groups: patients with sling, RT and anastomotic VU stricture previously treated by urethrotomy. The main limitations remain: the need for the patient to have satisfactory cognitive function and manual dexterity to handle the sphincter, present a non-negligible rate of re-intervention due to mechanical and non-mechanical complications. © 2014 Associação Portuguesa de Urologia. Published by Elsevier España, S.L.U. All rights reserved.
Abstract
Introduction : The artificial urinary sphincter (AUS) is the gold standard for surgical treatment of male stress urinary incontinence. Objective : Evaluate the results of [...]
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Dynamic sentinel node biopsy in invasive squamous cell carcinoma of the penis: a single uro‐oncology Portuguese centre experience
R. Cruz, R. Freitas, P. Araújo, L. Violante, R. Azevedo, J. Oliveira, S. Magalhães

Collection of Acta Urológica Portuguesa (2017).

Abstract
The 2014 European Association of Urology (EAU) guidelines on Penile cancer recommend dynamic sentinel node biopsy (DSNB) as a standard staging method for intermediate and high risk squamous cell carcinoma of the penis (SCCp), (≥ T1G2), c N0. The aim of this work is to evaluate the false negative rate and morbidity of our DSNB series. Since 2005 to 2014, 23 patients with SCCp and a patient with melanoma of the distal urethra, cN0, underwent DSNB in the urology department of Porto Portuguese Oncology Institute ‐ IPOPFG, EPE, Portugal. Bilateral inguinal ultrasound scan and fine needle aspiration cytology (FNAC) of suspicious inguinal nodes were not performed before DSNB. Lymphoscintigraphy starts in the morning of surgery with peri‐tumoral injection of albumin nanocoloid labeled with 99m Tc. Peri‐operatively, patent blue is injected into the dermis in peri‐tumoral location. The sentinel node is identified during surgery with the aid of lymphoscintigraphy images, a portable probe which detects gamma rays and identification of the blue dye in lymph nodes and vessels. The false negative rate was calculated per patient. The complication rate was calculated per groin within 30 days of DSNB. In 23 patients with SCCp, lymphoscintigraphy was bilateral in 7 patients. Biopsy was bilateral in 11 patients, with a mean number of lymph nodes excised per patient of 2, negative for metastasis in 20 patients. After median follow‐up of 45.5 months, we had a false negative. The false negative rate [1 false negative / (3 true positive + 1 false negative)] was 25%. The complication rate of BDGS per groin was 5.8%, with 2 minor linfoceles (Clavien I). Inguinal ultrasound and FNAC of suspicious lymph nodes before DSNB, although operator‐dependent, seems very important to decrease our false negative rate. The referral of patients with SCCp for DSNB can increase the number of patients undergoing this nodal staging method in Portugal. The DSNB morbidity is minimal.
Abstract
The 2014 European Association of Urology (EAU) guidelines on Penile cancer recommend dynamic sentinel node biopsy (DSNB) as a standard staging method for intermediate and [...]
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Terapêuticas focais no tratamento do carcinoma da próstata localizado: o papel da eletroporação irreversível – presente ou futuro?
P. Fernandes, B. Pereira

Collection of Acta Urológica Portuguesa (2017).

Abstract
In the PSA era, the incidence of localized prostate cancer has been increasing. This reality requires new therapeutic strategies, in order to give an answer to patients, in whom active surveillance may be indicate but desire more interventionist strategy with minimal side effects and without compromising cancer control. In these cases, focal therapies that include irreversible electroporation may be effective alternative strategies. The irreversible electroporation is an emergent approach on focal treatment of localized PCa. The nonthermal mechanism that preserves the tissue architecture without damaging tissue structures, such as vessels and nerves within the target region, is the main advantage comparatively to other techniques used in focal treatment. The number of clinical studies is reduced and the results still immature.
Abstract
In the PSA era, the incidence of localized prostate cancer has been increasing. This reality requires new therapeutic strategies, in order to give an answer to patients, in [...]
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Treatment of cystine calculi - an observational retrospective review
D. Castelo, E. Silva, P. Moreira, P. Simões, H. Dinis, A. Figueiredo, A. Mota

Collection of Acta Urológica Portuguesa (2017).

Abstract
Introduction : Patients with cystinuria require multiple and varied treatments due to disease persistence and recurrence. In this study we analyzed therapeutic modalities and outcomes in the treatment of cystine calculi at a single academic center over the last 7 years. Materials and methods : We retrospectively analyzed patients undergoing invasive treatment of cystine calculi at our institution in the period between January 2006 and March 2013. Medical and surgical interventions and patient outcomes regarding stone-free status and renal function were considered. Results : A total of 7 cystinuric patients were invasively treated in our institution over the period of 7 years from January 2006 to March 2013. Of these 4 were male and 3 female with an average age at last follow-up of 39 years (range 19-59). Treatment modalities included medical therapy with high fluid intake, sodium restriction and urine alkalinization (all 7 patients), captopril (6 patients), and penicillamine (1 patient). These patients underwent a total of 156 procedures, with an average of 22.3 procedures per patient. All patients underwent extracorporeal shockwave lithotripsy (SWL), with a mean of 20 sessions per patient, range 8-35). Other treatment modalities included ureterorenoscopy and intracorporeal lithotripsy, (9 procedures in 4 patients, mean = 2, range 1-4), percutaneous nephrolithotomy (PCNL), (3 procedures in 3 patients), pyelolithotomy (2 procedures in 2 patients, one laparoscopic and one open) and one open nephrectomy (sepsis due to an atrophic kidney at presentation). Three patients have been stone free for the last 12 months, all have undergone PCNL or pyelolithotomy. Three patients have had serial renal scintigraphy, all maintained global and differential renal function over a period of 6 years (2 patients) and 2 years (1 patient) despite continued invasive procedures. Conclusions : In our series, more invasive procedures (PCNL or pyelolithotmy) were required for debulking disease burden or achieving a stone-free status. Medical therapy and repeated minimally invasive procedures, especially SWL, were required for preventing recurrence and treating residual stones. Despite the frequent use of procedures with potential deleterious effect for the kidney, in our series renal function was not affected either by the disease or its aggressive treatment over a period of several years. © 2014 Associação Portuguesa de Urologia. Published by Elsevier España, S.L.U. All rights reserved.
Abstract
Introduction : Patients with cystinuria require multiple and varied treatments due to disease persistence and recurrence. In this study we analyzed therapeutic modalities [...]
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Erectile dysfunction and diabetes – evaluation of molecular alterations induced by oxidative stress
A. Castela, P. Gomes, V. Domingues, P. Paíga, R. Costa, P. Vendeira, C. Costa

Collection of Acta Urológica Portuguesa (2017).

Abstract
Erectile dysfunction (ED) is one of the most common complications of diabetes, being oxidative stress an important feature of diabetic ED. Deleterious events induced by oxidative stress lead to crucial cellular and tissue alterations targeted by oxidative lesions. However, the noxious effects of oxidative stress mechanisms in penile tissue with the progression of diabetes, remains unclear. We intended to evaluate systemic and penile oxidative stress in an early and late stage of diabetes. Male Wistar rats were divided in groups: 2 and 8‐weeks of streptozotocin‐induced type 1 diabetes, and age‐matched controls. Systemic oxidative stress was evaluated in urine by hydrogen peroxide (H2 O2 ) quantification and in plasma by reduced/oxidized glutathione (GSH/GSSG) ratio. Penile oxidative status was assessed by H2 O2 production and by the evaluation of protein nitration through the detection of 3‐nitrotyrosine (3‐NT). 3‐NT was quantified by Western blotting analysis and immunohistochemistry allowed to identify its cavernosal cellular location. Systemic evaluation revealed a significant increase in urinary H2 O2 levels in both diabetic groups. A significant decrease of circulating GSH/GSSG ratio was observed in animals with late stage diabetes. In cavernosal tissue, H2 O2 production was significantly increased at 8‐weeks diabetes. Regarding 3‐NT cavernosal formation, data revealed a significant increment in advanced diabetes and a predominant location in cavernosal smooth muscle cells. We observed that systemic and cavernosal noxious effects induced by oxidative stress are predominant in advanced diabetes. Increased penile protein oxidative modifications in late‐staged diabetes may be responsible for structural/functional deregulations in cellular/molecular systems, contributing to the development of diabeticassociated ED.
Abstract
Erectile dysfunction (ED) is one of the most common complications of diabetes, being oxidative stress an important feature of diabetic ED. Deleterious events induced by oxidative [...]
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Female urethral diverticula: A contemporary review
J. Neves, J. Dores, M. Coelho

Collection of Acta Urológica Portuguesa (2017).

Abstract
Urethral diverticula affect from 0.6 to 4.7% of women, are a frequent cause of persistent urinary symptoms and can present with complications such as lithiasis and malignization. Today, underdiagnosis and diagnostic and therapeutic delay of female urethral diverticula are still common. The aim of this article is to analyse the state of art regarding ethiology, diagnosis and therapeutics of this disease. Bibliographic revision of articles published until January/2014 after search of the database Medline for the keywords: “female urethral diverticula”, “female urethral diverticulum”, “urethral diverticula”, “urethral diverticulum” and “female urethra”, and of bibliographic references of the articles obtained. Most female urethral diverticula are secondary to infection of the periurethral and urethral glands. Despite the classically described triad of dysuria, dyspareunia and post‐void dribbling, the clinical manifestations are diverse and unspecific. Over a third are palpable on gynaecologic examination. Imaging exams, namely magnetic resonance and ultrasound, have high diagnostic capability and contribute to surgical planning. Depending on location, conformation and associated symptoms, urethral diverticula can be managed conservatively or, more frequently, surgically. Clinical evaluation is still essential for the diagnosis of female urethral diverticula. Currently, magnetic resonance is considered to be the best modality to diagnose the diverticula and to exclude pre‐ and post‐operative complications. Less invasive techniques have been described but transvaginal urethral diverticulectomy yields the highest symptomatic cure rates. Awareness of the medical community is the most powerful weapon to reduce the underdiagnosis and diagnostic delay associated with female urethral diverticula.
Abstract
Urethral diverticula affect from 0.6 to 4.7% of women, are a frequent cause of persistent urinary symptoms and can present with complications such as lithiasis and malignization. [...]
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Urolithiasis in the XXI century: bibliometric analysis of scientific publications in the last decade
I. Braga, F. Branco, J. Cabral, N. Louro, V. Cavadas, A. Fraga

Collection of Acta Urológica Portuguesa (2017).

Abstract
As the prevalence of urolithiasis is growing and there has been an increase in technologies and minimally invasive techniques in all areas of surgery, it would be expected that the total number of publications about this disease should increase. We hypothesized if there is also an evident trend towards the increase of urolithiasis related publications in urology journals. We evaluated the publications in five prestigious urology journals over the last decade, in order to perform a bibliometric analysis of every article published related to urinary lithiasis. An electronic search was performed using PubMed and all issues of British Journal of Urology International® (BJU Int), European Urology® (Eur Urol), Journal of Endourology® (J Endourol), Journal of Urology® (J Urol) and Urology® (Urology) were consulted from 2001 to 2010. All articles related to renal and ureteral lithiasis were collected, recorded and analyzed. A total of 30, 847 articles were published in these five prestigious journals. The J Urol was the journal with the most number of articles published per year with an average of 1146 papers. J Endourol was the publication with less publicated articles in this decade, with an average of 231 papers per year. There was a total of 1425 urolithiasis related papers in all journals. The J Endourol was the journal with the greatest number of urolithiasis related articles published in the period of analysis, with a total of 545 articles. The ratio of urolithiasis related articles and the total articles published per year in each journal was analyzed. The J Endourol was the publication with the greatest ratio. Eur Urol was the journal with less publications in urolithiasis, with ratios ranging from 0 in the year of 2010 and 5.3% in the year of 2003, with a decrease in the last years. All the other journals maintained a stable ratio of publications. Urolithiasis as a great subject to urologists practice would be expected to be an important source of original research studies in the more active urology journals. However, our study showed that, during the last decade, there was a steady number of urolithiasis related articles published in several journals.
Abstract
As the prevalence of urolithiasis is growing and there has been an increase in technologies and minimally invasive techniques in all areas of surgery, it would be expected [...]
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Radical cystectomy / experience of an oncology center
P. Araújo, R. Cruz, R. Freitas, A. Morais, J. Oliveira

Collection of Acta Urológica Portuguesa (2017).

Abstract
To present our clinical and surgical experience of radical cystectomy in bladder cancer, evaluate postoperative complications and overall survival. We performed a retrospective analysis of all patients undergoing radical cystectomy for bladder cancer between 2006 and 2010. Pathological characteristics were described based on 2009 TNM classification. We evaluated postoperative complications in the first 30 days after surgery according to the Clavien-Dindo classification and determined overall survival. We analyzed the data from 195 patients with a mean age of 67.8 years (28-87 years). 82.6% were male. The median follow-up was 2.5 years. Urothelial cancer was diagnosed in 93.8% cases. The majority of patients had extravesical disease with pathologic T3 stage in 28.7% and T4 in 22.1%. 32.8% of patients who underwent lymphadenectomy had positive lymph nodes. The most frequent urinary diversion was the ileal conduit, performed in 79% of cases, followed by neobladder in 10.3%. Postoperative complications were reported in 40.5% of patients, 28.2% were grade I/II and 12.3% were grade III-V, with a mortality rate of 3.6%. The overall survival at 3 years was 54% and at 5 years was 48%. The cases with disease localized to the bladder (≤ pT2N0) showed a 3-year survival of 89%. The presence of extravesical disease (≥ pT3) and lymph nodes metastasis confirmed to be poor prognostic factors, with a 3-year overall survival of 46% and 22%, respectively. This series results show that radical cystectomy is a complex surgery but with reasonable early postoperative morbidity and mortality. Surgery should be performed in the early stages of disease in order to offer the best survival outcomes.
Abstract
To present our clinical and surgical experience of radical cystectomy in bladder cancer, evaluate postoperative complications and overall survival. We performed a retrospective [...]
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Renal oncocytoma: Is URO‐CT useful in histological diagnosis?
J. Dores, P. Kronenberg, P. Santos, S. Ferreira, F. Gomes

Collection of Acta Urológica Portuguesa (2017).

Abstract
Over the past few years, the increasing use of cross‐sectional imaging, including ultrasound and computed tomography imaging, resulted in an increase incidental diagnosis of renal tumors, especially small renal masses (< 4 cm). The knowledge that 30% of these masses may be benign, including oncocytomas led to the investigation for more effective methods of diagnosis in order to avoid overtreatment situations. The authors decided to analyse and compare contrast enhancement patterns of oncocytomas and clear‐cell renal cell carcinoma (ccRCC) to predict histology. Between 2004‐2015 we retrospectively identified 32 patients with either histological confirmation of renal oncocytoma (N = 16) or ccRCC (N = 16) who underwent percutaneous biopsy, total or partial nephrectomy. The relative attenuation of solid renal lesions and normal renal cortex was determined in the unenhanced and nephrographic phase. Statistical comparison was carried out by Mann‐Withney test. The oncocytomas and cc‐RCC average size was 3.7 cm [1.8 to 14] and 3.5 cm [1.9 to 8.4], respectively. The average attenuation in the unenhanced phase was 33 HU and 32 HU, respectively. In nephrographic phase, the average contrast enhancement was 47.5 and 47.4 H, respectively. In nephrographic phase, the attenuation difference between the oncocytomas and normal renal cortex was 43.5 HU and the attenuation difference between the cc‐RCC and normal renal cortex was 59.7 HU. These results were statistically significant (p < 0.05). In the nephrographic phase, URO‐CT reveals that oncocytomas have greater isodensity to the normal renal cortex compared to cc‐RCC. This finding can help us to determine which lesions we should biopsy or not.
Abstract
Over the past few years, the increasing use of cross‐sectional imaging, including ultrasound and computed tomography imaging, resulted in an increase incidental diagnosis [...]
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Testis‐sparing surgery attempt: Case report
J. Dores, B. Graça, M. Coelho, R. Manso, F. Gomes

Collection of Acta Urológica Portuguesa (2017).

Abstract
Until the late 1980s, it was considered that any testicular mass, if suspicious, should be removed totally by radical orchiectomy, however, a marked increase in incidental testicular mass diagnosis, the high accuracy of diagnosis obtained from frozen section examinations, and evidence showing the potential advantages of testis‐sparing surgery, threw into question the need to sacrifice the entire testis even when a normal contralateral testis was present. We present a 23‐year‐old patient who was asymptomatic at diagnosis of a non‐palpable testicular mass with a size of approximately 7.5 mm and negative for tumor markers. He underwent a Testis‐sparing surgery guided by ultrasound with frozen section examination, however, with the suspicious of Germ cell tumor, it was decided to complete the orchiectomy. The final histological results were Leydig cell tumor. Given the high likelihood of non‐palpable and small testicular lesions being benign (80%), the negative impact of radical orchiectomy on spermatogenesis, cosmetic aspects, and endocrine function, impossible to ignore, Testis‐sparing surgery is a procedure that although it is not a standard procedure must be employed as the first approach in selected cases and specialized reference centers.
Abstract
Until the late 1980s, it was considered that any testicular mass, if suspicious, should be removed totally by radical orchiectomy, however, a marked increase in incidental [...]
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Características biológicas do carcinoma urotelial da bexiga: à descoberta de potenciais biomarcadores
J. Afonso, R. Freitas, F. Lobo, A. Morais, T. Amaro, R. Reis, F. Baltazar, A. Longatto-Filho, L. Santos, J. Oliveira

Collection of Acta Urológica Portuguesa (2017).

Abstract
Urothelial bladder carcinoma (UBC), the most frequent type (90%) of bladder cancer and the second most common malignancy of the urogenital region, is a relatively well understood type of cancer, with numerous studies concerning pathogenetic pathways, natural history and bladder tumor biology being reported. Despite this, it continues to remain a challenge in the oncology field, mostly due to its relapsing and progressive nature, and to the heterogeneity in the response to cisplatin-containing regimens. Although the formulae based on clinical staging and histopathological parameters are classically used as diagnostic and prognostic tools, they have proven insufficient to characterize the individual biological features and clinical behaviour of the tumours. Understanding the pathobiology of the disease can add important information to these classical criteria, and contribute to accurately predict outcome and individualize therapy for UBC patients. In this line of investigation, we found that tumour angiogenesis and lymphangiogenesis, the process of invasion and metastasis and the energy metabolism reprogramming/tumour microenvironment encompass several potential biomarkers that seem to infl bladder cancer aggressiveness and chemoresistance. We particularly highlight the roles of lymphovascular invasion, and of RKIP, CD147 and MCT1 immunoexpressions, as relevant prognostic and/or predictive biomarkers, and as promising areas of therapeutic intervention, eliciting for the development of additional studies that can validate and further explore these biomarkers.
Abstract
Urothelial bladder carcinoma (UBC), the most frequent type (90%) of bladder cancer and the second most common malignancy of the urogenital region, is a relatively well understood [...]
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Prostatectomia radical laparoscópica versus aberta: margens cirúrgicas
R. Abreu, P. Bargão, B. Graça, M. Lourenço, M. Coelho, F. Ribeiro, P. Cardoso, J. Varregoso, F. Ferrito, C. Gomes

Collection of Acta Urológica Portuguesa (2017).

Abstract
Laparoscopic radical prostatectomy has become an accepted alternative to open surgery. Our goal is to compare the oncological outcome of both approaches. The prospective study was initiated in September 2012, during 10 months. The high risk tumors were excluded from the study, only low and intermediate risk were included. We evaluated the following parameters: age, PSA, biopsy Gleason score, operative time, blood units, surgical margins, complications, Gleason score and TNM stage of the surgical specimen. Within 10 months, 45 patients underwent radical prostatectomy. 24 underwent laparoscopic approach and 21 the open approach. In the laparoscopic group, 70.8% (17) presented negative margins, 25% (6) positive margins and 4.17% (1) not suitable for classification. In the open approach 66.7% (14) presented negative margins, 28.6% (6) presented positive margins and 4.76% (1) not suitable for classification. It was used a Chi-Square Test considering positive and negative margins. No statistically differences were found (p value = 0.79). We evaluated the distribution of the different tumor stages T2a, T2b, T2c, T3a and T3b (TNM) in both groups. No difference was found in the distribution of the tumor stages in both groups. We have used a chi-square test (p value = 0.23). There is no association between the margins and the surgical approaches, and no association between the tumor stages and the two surgical approaches. We can conclude that the laparoscopic approach can be an alternative in low and intermediate risk cancers, even in low volume centres. © 2014 Associação Portuguesa de Urologia. Published by Elsevier España, S.L.U. All rights reserved.
Abstract
Laparoscopic radical prostatectomy has become an accepted alternative to open surgery. Our goal is to compare the oncological outcome of both approaches. The prospective study [...]
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New draft 1
Collection of Engineering Science and Technology, an International Journal (2017).
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Investigation on stacked cascade multilevel inverter by employing single-phase transformers
Y. Suresh, A. Panda

Collection of Engineering Science and Technology, an International Journal (2017).

Abstract
In the present paper a new version of multilevel inverter is investigated. This new version is based on hybrid association of commutation cells with H-bridge cells. The association allows a significant reduction of the volume of the capacitors. In fact, presented topology allows us to work on higher input voltage levels with the same power switches. This new version is generally called as SCMI (stacked cascade multilevel inverter). The proposed inverter has potential to generate high quality waveforms, reduction in switching frequency, capable to operate at higher voltage levels and finally utilizes minimum number of switching components. The presented version of SCMI is simulated in Matlab-simulink and further, experimental validation is carried out in the laboratory with prototype setup.
Abstract
In the present paper a new version of multilevel inverter is investigated. This new version is based on hybrid association of commutation cells with H-bridge cells. The association [...]
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Multi-response optimization of process parameters for TIG welding of Incoloy 800HT by Taguchi grey relational analysis
A. Srirangan, S. Paulraj

Collection of Engineering Science and Technology, an International Journal (2017).

Abstract
Incoloy 800HT which was selected as one of the prominent material for fourth generation power plant can exhibit appreciable strength, good resistance to corrosion and oxidation in high temperature environment. This study focuses on the multi-objective optimization using grey relational analysis for Incoloy 800HT welded with tungsten inert arc welding process with N82 filler wire of diameter 1.2 mm. The welding input parameters play a vital role in determining desired weld quality. The experiments were conducted according to L9 orthogonal array. The input parameter chosen were the welding current, Voltage and welding speed. The output response for quality targets chosen were the ultimate tensile strength and yield strength (at room temperature, 750 °C) and impact toughness. Grey relational analysis was applied to optimize the input parameters simultaneously considering multiple output variables. The optimal parameters combination was determined as A2 B1 C2 i.e. welding current at 110 A, voltage at 10 V and welding speed at 1.5 mm/s. ANOVA method was used to assess the significance of factors on the overall quality of the weldment. The output of the mechanical properties for best and least grey relational grade was validated by the metallurgical characteristics:
Abstract
Incoloy 800HT which was selected as one of the prominent material for fourth generation power plant can exhibit appreciable strength, good resistance to corrosion and oxidation [...]
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Shadow removal using sparse representation over local dictionaries
R. Sasi, V. Govindan

Collection of Engineering Science and Technology, an International Journal (2017).

Abstract
The presence of shadow in an image is a major problem associated with various visual processing applications such as object recognition, traffic surveillance and segmentation. In this paper, we introduce a method to remove the shadow from a real image using the morphological diversities of shadows and sparse representation. The proposed approach first generates an invariant image and further processing is applied to the invariant image. Here, shadow removal is formulated as a decomposition problem that uses separate local dictionaries for shadow and nonshadow parts, without using single global or fixed generic dictionary. These local dictionaries are constructed from the patches extracted from the residual of the image obtained after invariant image formation. Finally, non-iterative Morphological Component Analysis-based image decomposition using local dictionaries is performed to add the geometric component to the non-shadow part of the image so as to obtain shadow free version of the input image. The proposed approach of shadow removal works well for indoor and outdoor images, and the performance has been compared with previous methods and found to be better in terms of RMSE.
Abstract
The presence of shadow in an image is a major problem associated with various visual processing applications such as object recognition, traffic surveillance and segmentation. [...]
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Design of optimal input–output scaling factors based fuzzy PSS using bat algorithm
D. Sambariya, R. Gupta, R. Prasad

Collection of Engineering Science and Technology, an International Journal (2017).

Abstract
In this article, a fuzzy logic based power system stabilizer (FPSS) is designed by tuning its input–output scaling factors. Two input signals to FPSS are considered as change of speed and change in power, and the output signal is considered as a correcting voltage signal. The normalizing factors of these signals are considered as the optimization problem with minimization of integral of square error in single-machine and multi-machine power systems. These factors are optimally determined with bat algorithm (BA) and considered as scaling factors of FPSS. The performance of power system with such a designed BA based FPSS (BA-FPSS) is compared to that of response with FPSS, Harmony Search Algorithm based FPSS (HSA-FPSS) and Particle Swarm Optimization based FPSS (PSO-FPSS). The systems considered are single-machine connected to infinite-bus, two-area 4-machine 10-bus and IEEE New England 10-machine 39-bus power systems for evaluating the performance of BA-FPSS. The comparison is carried out in terms of the integral of time-weighted absolute error (ITAE), integral of absolute error (IAE) and integral of square error (ISE) of speed response for systems with FPSS, HSA-FPSS and BA-FPSS. The superior performance of systems with BA-FPSS is established considering eight plant conditions of each system, which represents the wide range of operating conditions.
Abstract
In this article, a fuzzy logic based power system stabilizer (FPSS) is designed by tuning its input–output scaling factors. Two input signals to FPSS are considered as change [...]
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Analysis of heatlines and entropy generation during double-diffusive MHD natural convection within a tilted sinusoidal corrugated porous enclosure
S. Hussain

Collection of Engineering Science and Technology, an International Journal (2017).

Abstract
The natural convection and entropy generation during double-diffusive MHD natural convection in a tilted sinusoidal corrugated porous enclosure is investigated numerically in this work by using heatline visualization technique. The top and bottom horizontal walls are assumed as adiabatic and non-diffusive, while the left and right vertical corrugated sidewalls are maintained at a constant hot and cold temperatures and concentrations respectively. The flow in the enclosure is subjected to an inclined magnetic field. The enclosure is filled with an electrically conducting fluid [Pr = 0.024] saturated with a porous media. The numerical computations are presented for various values of Rayleigh number (Ra), Hartmann number (Ha), Lewis number (Le), Darcy number (Da), buoyancy ratio (N), magnetic field orientation angle (φ) and enclosure inclination angle (Φ). In addition, the entropy generation due to fluid friction, thermal gradients, diffusion, and magnetic field beside the total entropy generation are studied and discussed. It is found that the flow circulation decreases strongly when the magnetic field applied horizontally and the enclosure is considered vertical. Heatline visualization concept is successfully applied to the considered problem. The average Nusselt number decreases when the Lewis number increases, while the average Sherwood number increases when the Lewis number increases. Also, both average Nusselt and Sherwood numbers increase when the Darcy number and buoyancy ratio increase. Moreover, the results show that the entropy generations due to magnetic field when the enclosure is subjected to the horizontal magnetic field are higher than the corresponding values when it subjected to the vertical magnetic field.
Abstract
The natural convection and entropy generation during double-diffusive MHD natural convection in a tilted sinusoidal corrugated porous enclosure is investigated numerically [...]
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Magneto-dielectric properties of doped ferrite based nanosized ceramics over very high frequency range
A. Saini, P. Kumar, B. Ravelo, S. Lallechere, A. Thakur, P. Thakur

Collection of Engineering Science and Technology, an International Journal (2017).

Abstract
In the present study, indium doped nano sized nickel zinc cobalt based ferrite ceramics with composition Ni0.5 Zn0.3 Co0.2 Inx Fe2-x O4 (x = 0.2 and 0.4) were synthesized by a co-precipitation technique. Powdered sample has been pre-sintered at 800 °C, pressed into toroids and finally sintered at 1000 °C. The single phase formation of the presintered powder has been confirmed by X ray diffraction (XRD). The average particle size of the presintered powder has been estimated by field emission scanning electron microscope (FESEM) and found to be about ~60 nm for x = 0.2 and ~80 nm at x = 0.4. The electromagnetic characterization has been made using vector network analyzer. High value of permeability (17.3 and 15.2 for x = 0.2 and 0.4 respectively) with low magnetic loss tangent of 10−1 order were obtained. Permittivity of 8.2 and 10, and dielectric loss tangent of the order of 10−2 were also achieved. With the measured electromagnetic parameters, miniaturization factor of 12.32 and normalized characteristic impedance close to unity (1.23) were obtained up to 100 MHz frequency. These fascinating parameters definitely propose Ni0.5 Zn0.3 Co0.2 In0.4 Fe1.6 O4 ceramics as a substrate material for miniaturized antenna in very high frequency band. Possible reasons and mechanisms of electromagnetic properties for different concentrations of indium are discussed in the paper.
Abstract
In the present study, indium doped nano sized nickel zinc cobalt based ferrite ceramics with composition Ni0.5 Zn0.3 Co0.2 Inx Fe2-x O4 (x = 0.2 and 0.4) were synthesized [...]
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Evaluation of in-cylinder mixture homogeneity in a diesel HCCI engine – A CFD analysis
N. Ramesh, J. Mallikarjuna

Collection of Engineering Science and Technology, an International Journal (2017).

Abstract
Performance and emission characteristics of HCCI engines depend on achieving a good in-cylinder homogeneous mixture. The formation of in-cylinder mixture depends on many engine parameters, which need optimization. In addition, as of now, there is no direct way to clearly describe and estimate in-cylinder mixture homogeneity. In the CFD analysis, it is evaluated indirectly using contour plots of equivalence ratio, variation of in-cylinder pressure with crank angles, heat release curves or by the comparison of emissions. In this study, an attempt has been made to develop methods to evaluate the in-cylinder mixture homogeneity by the CFD analysis using AVL-FIRE. Here, global and local in-cylinder fuel distribution and in-cylinder fuel distribution index are used to evaluate the mixture homogeneity. In order to evaluate these methods, mixture homogeneities in two cases of fuel injections with 7- and 10-hole injector are compared. Finally, we found that the global fuel distribution (GFD) plot helps direct quantitative assessment of mixture distribution in various ER range. However, the GFD method cannot explain the spatial variation of fuel distribution and does not provide mixture homogeneity on a simple scale. In the method of plotting fuel distribution index, the overall homogeneity will be evaluated on a scale of 0 to 1 by a simple way. In the method of plotting local fuel distribution (LFD), the spatial variation of mixture homogeneity is well defined in local zones both in radial and axial directions. Further, these proposed methods help us to reduce the computation time significantly.
Abstract
Performance and emission characteristics of HCCI engines depend on achieving a good in-cylinder homogeneous mixture. The formation of in-cylinder mixture depends on many engine [...]
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Microcontroller USB interfacing with MATLAB GUI for low cost medical ultrasound scanners
J. Raj, S. Rahman, S. Anand

Collection of Engineering Science and Technology, an International Journal (2017).

Abstract
This paper presents an 8051 microcontroller-based control of ultrasound scanner prototype hardware from a host laptop MATLAB GUI. The hardware control of many instruments is carried out by microcontrollers. These microcontrollers are in turn controlled from a GUI residing in a computing machine that is connected over the USB interface. Conventionally such GUIs are developed using ‘C’ language or its variants. But MATLAB GUI is a better tool, when such GUI programs need to do huge image/video processing. However interfacing MATLAB with the microcontroller is a challenging task. Here, MATLAB interfacing through an intermediate MEX ‘C’ language program is presented. This paper outlines the MEX programming methods for achieving the smooth interfacing of microcontrollers with MATLAB GUI.
Abstract
This paper presents an 8051 microcontroller-based control of ultrasound scanner prototype hardware from a host laptop MATLAB GUI. The hardware control of many instruments [...]
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Effects of induced magnetic field and homogeneous–heterogeneous reactions on stagnation flow of a Casson fluid
C. Raju, N. Sandeep, S. Saleem

Collection of Engineering Science and Technology, an International Journal (2017).

Abstract
In this study, we analyzed the induced magnetic field effect on the stagnation-point flow of a non-Newtonian fluid over a stretching sheet with homogeneous–heterogeneous reactions and non-uniform heat source or sink. The transformed ordinary differential equations are solved numerically using Runge–Kutta and Newtons method. For physical relevance we analyzed the behavior of homogeneous and heterogeneous profiles individually in the presence of induced magnetic field. The effects of different non-dimensional governing parameters on velocity, induced magnetic field, temperature and concentration profiles, along with the skin friction coefficient and local Nusselt number, are discussed and presented through graphs. The results of the present study are validated by comparing with the existed literature. Results indicate that induced magnetic field parameter and stretching ratio parameter have the tendency to enhance the heat transfer rate.
Abstract
In this study, we analyzed the induced magnetic field effect on the stagnation-point flow of a non-Newtonian fluid over a stretching sheet with homogeneous–heterogeneous [...]
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Bat algorithm optimized fuzzy PD based speed controller for brushless direct current motor
K. Premkumar, B. Manikandan

Collection of Engineering Science and Technology, an International Journal (2017).

Abstract
In this paper, design of fuzzy proportional derivative controller and fuzzy proportional derivative integral controller for speed control of brushless direct current drive has been presented. Optimization of the above controllers design is carried out using nature inspired optimization algorithms such as particle swarm, cuckoo search, and bat algorithms. Time domain specifications such as overshoot, undershoot, settling time, recovery time, and steady state error and performance indices such as root mean squared error, integral of absolute error, integral of time multiplied absolute error and integral of squared error are measured and compared for the above controllers under different operating conditions such as varying set speed and load disturbance conditions. The precise investigation through simulation is performed using simulink toolbox. From the simulation test results, it is evident that bat optimized fuzzy proportional derivative controller has superior performance than the other controllers considered. Experimental test results have also been taken and analyzed for the optimal controller identified through simulation.
Abstract
In this paper, design of fuzzy proportional derivative controller and fuzzy proportional derivative integral controller for speed control of brushless direct current drive [...]
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Investigation on energy efficient sensor node placement in railway systems
A. Philipose, R. A

Collection of Engineering Science and Technology, an International Journal (2017).

Abstract
Recently wireless sensor network (WSN) has been widely used for monitoring railway tracks and rail tunnels. The key requirement in the design of such WSN is to minimize the energy consumption so as to maximize the network lifetime. This paper includes the performance of an improved medium access control (MAC) protocol, namely, time adaptive-bit map assisted (TA-BMA) protocol, for the purpose of communication between the sensors placed in a railway wagon. The train is considered to be moving at a constant speed, and the sensor nodes are stationary with respect to the motion of train. The effect of mobility on the proposed MAC protocol is determined using genetic algorithm (GA), and the observed increase in energy consumption on considering mobility is 18.51%. Performance analysis of the system model is carried out using QualNet (ver. 7.1), and the energy consumption in transmit mode, receive mode, percentage of time in sleep mode, end-to-end delay and throughput are investigated.
Abstract
Recently wireless sensor network (WSN) has been widely used for monitoring railway tracks and rail tunnels. The key requirement in the design of such WSN is to minimize the [...]
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Free vibration analysis of pre-stressed FGM Timoshenko beams under large transverse deflection by a variational method
A. Paul, D. Das

Collection of Engineering Science and Technology, an International Journal (2017).

Abstract
A theoretical study on free vibration behavior of pre-stressed functionally graded material (FGM) beam is carried out. Power law variation of volume fraction along the thickness direction is considered. Geometric non-linearity is incorporated through von Kármán non-linear strain–displacement relationship. The governing equation for the static problem is obtained using minimum potential energy principle. The dynamic problem for the pre-stressed beam is formulated as an eigenvalue problem using Hamiltons principle. Three classical boundary conditions with immovable ends are considered for the present work, namely clamped–clamped, simply supported–simply supported and clamped–simply supported. Four different FGM beams, namely Stainless Steel–Silicon Nitride, Stainless Steel–Zirconia, Stainless Steel–Alumina and Titanium alloy–Zirconia, are considered for generation of results. Numerical results for non-dimensional frequency parameters of undeformed beam are presented. The results are presented in non-dimensional pressure-displacement plane for the static problem and in non-dimensional frequency-displacement plane for the dynamic problem. Comparative frequency-displacement plots are presented for different FGMs and also for different volume fraction indices.
Abstract
A theoretical study on free vibration behavior of pre-stressed functionally graded material (FGM) beam is carried out. Power law variation of volume fraction along the thickness [...]
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Effect of welding parameters on pitting behavior of GTAW of DSS and super DSS weldments
P. Paulraj, R. Garg

Collection of Engineering Science and Technology, an International Journal (2017).

Abstract
This work focuses on the effect of welding parameters on corrosion behavior of welded duplex stainless steel (DSS) and super duplex stainless steel (SDSS). The effect of welding parameters, such as heat input, inter-pass temperature, cooling rate, shielding/back purging gas, on corrosion behavior was studied. DSS and SDSS pipes were welded with Gas Tungsten Arc Welding (GTAW) process. After welding, the test samples were non-destructively tested to ensure no defects and test samples were prepared for microstructural examinations and ferrite content measurements. The root region had complex microstructure because of the repetitive heating of the zone during different weld layers. It was observed that at low heat input desirable microstructure was formed. The test samples were subjected to corrosion tests, i.e. ASTM G48 test for the determination of pitting corrosion rate, potentiodynamic polarization tests, and potentiostatic tests to verify susceptibility of the alloys to corrosion attack. DSS weldments had CPT in between 23 °C to 27 °C and SDSS weldments had CPT between 37 °C to 41 °C in potentiostatic measurements. The corrosion test results were correlated to the microstructures of the weldments. The pitting resistance of individual phases was studied and the effect of secondary austenite on corrosion attack was also observed.
Abstract
This work focuses on the effect of welding parameters on corrosion behavior of welded duplex stainless steel (DSS) and super duplex stainless steel (SDSS). The effect of welding [...]
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Dry sliding wear behavior of epoxy fly ash composite with Taguchi optimization
A. Pattanaik, M. Satpathy, S. Mishra

Collection of Engineering Science and Technology, an International Journal (2017).

Abstract
Epoxy resin matrix composite reinforced with fly ash particles was prepared by ultrasonic stirring method. Pin-on-disc wear test of the composite was carried out and compared according to Taguchi design-of-experiment. An orthogonal array exhibited and examined the influencing parameters like % of fly ash debris, typical load, sliding speed and track distance on the composite. Signal to noise ratio analysis optimizes the parametric condition that yields minimum wear rate, minimum frictional force and minimum coefficient of friction. A multi-criteria decision analysis method, TOPSIS is used to optimize the output, and confirmation test has been done to verify the projected model. ANOVA shows that applied normal load plays a vital role in increasing dry sliding wear of epoxy composites.
Abstract
Epoxy resin matrix composite reinforced with fly ash particles was prepared by ultrasonic stirring method. Pin-on-disc wear test of the composite was carried out and compared [...]
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Influence of CaCO3 , Al2 O3 , and TiO2 microfillers on physico-mechanical properties of Luffa cylindrica /polyester composites
V. Patel, A. Dhanola

Collection of Engineering Science and Technology, an International Journal (2017).

Abstract
The development of natural fibre reinforced polymer composites has gained popularity in many applications due to their environment friendly characteristics over the synthetic fibre based polymer composites. This paper describes the fabrication and physical, mechanical, three-body abrasive wear and water absorption behaviour of Luffa fibre reinforced polyester composites with and without addition of micro-fillers of Al2 O3, CaCO3 and TiO2 . The ranking of the composite materials has been made by using Technique for order preference by similarity to ideal solution (TOPSIS) method with output parameters of their physical, mechanical and abrasive wear and water absorption attributes. The addition of microfillers has enhanced greatly the physical and mechanical properties of Luffa -fibre based composites. The addition of microfillers has influenced the physico-mechanical properties of Luffa -fibre based polyester composites in descending order of CaCO3, Al2 O3, and TiO2 .
Abstract
The development of natural fibre reinforced polymer composites has gained popularity in many applications due to their environment friendly characteristics over the synthetic [...]
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State of the art on tribological behavior of polymer matrix composites reinforced with natural fibers in the green materials world
E. Omrani, P. Menezes, P. Rohatgi

Collection of Engineering Science and Technology, an International Journal (2017).

Abstract
Natural fiber reinforced polymer composites have emerged as a potential environmentally friendly and cost-effective alternative to synthetic fiber reinforced composites. Therefore, in the past decade, a number of major industries, such as the automotive, construction and packaging industries, have shown a considerable interest in the progress of new natural fiber reinforced composite materials. The availability of natural fibers and the ease of manufacturing have tempted researchers to study their feasibility of their application as reinforcement and the extent to which they satisfy the required specifications in tribological applications. However, less information concerning the tribological performance of natural fiber reinforced composite material is available in the literature. Hence, the aim of this bibliographic review is to demonstrate the tribological behavior of natural fiber reinforced composites and find a knowledge about their usability for various applications that tribology plays a dominant role. This review presents the reported work on natural fiber reinforced composites with special reference to the type of fibers, matrix polymers, treatment of fibers and test parameters. The results show that composites reinforced with natural fibers have an improvement in tribological properties and their properties are comparable with conventional fibers. In addition, fiber treatment and fiber orientation are two important factors can affect tribological properties where treated fibers and normal oriented fibers exhibit better friction and wear behavior. This review is trying to evaluate the effect of test parameter including normal load and sliding speed on tribological properties, and the results vary based on type of reinforcement. Generally, due to their positive economic and environmental aspects, as well as their good tribological properties, natural composites are showing a good potential for employing in several applications.
Abstract
Natural fiber reinforced polymer composites have emerged as a potential environmentally friendly and cost-effective alternative to synthetic fiber reinforced composites. Therefore, [...]
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Hydromagnetic flow over an unsteady curved stretching surface
M. Naveed, Z. Abbas, M. Sajid

Collection of Engineering Science and Technology, an International Journal (2017).

Abstract
In this study, the boundary layer flow of an incompressible viscous fluid over an unsteady curved stretching surface is investigated in the presence of a variable applied magnetic field. Since the geometry is curved, the basic flow equations of the present problem are modeled using curvilinear coordinates. The obtained system is then reduced into nonlinear ordinary differential equations in two dependent quantities namely the fluid pressure and velocity by introducing suitable transformations. A numerical solution for fluid pressure and velocity is obtained by using a shooting method using Runge–Kutta integration scheme. The effects of various physical parameters on the fluid velocity and pressure distribution are shown through graphs and are discussed in detail. The comparison between the present and the existing results in the literature in special case for flat unsteady stretching, i.e. (K→∞K→∞ ), is found in good agreement.
Abstract
In this study, the boundary layer flow of an incompressible viscous fluid over an unsteady curved stretching surface is investigated in the presence of a variable applied [...]
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Experimental investigation on mechanical and microstructural properties of AISI 304 to Cu joints by CO2 laser
B. Moharana, S. Sahu, S. Sahoo, R. Bathe

Collection of Engineering Science and Technology, an International Journal (2017).

Abstract
Aim of the present work is to investigate mechanical and metallurgical characteristics of continuous wave CO2 laser welded dissimilar couple of AISI 304 stainless steel and commercially pure copper sheets in autogenous mode. Metallurgical analysis of the fusion zone has been done to understand the mixing and solidification behavior. Macroscopic examination has been carried out to observe the macro-segregation pattern of Cu, Fe and Cr rich phases in different zones, and the thickness of HAZ was found to be around 10 µm. The micro-channels formed from the steel side to weld pool describe that the copper solidifies first and provides the nucleation surface for the residual melt to grow. These tubular micro-channels formed may be due to carbide precipitation. The EDS analysis conforms the well mixing of SS and Cu inside the weld pool. The mechanical properties in terms of tensile stress found up to 201 MPa and the fracture are obtained outside the weld zone. Microhardness measurements over the fusion zone have been done to understand the keyhole growth and quenching, solidification sequence and stress distribution over the full area.
Abstract
Aim of the present work is to investigate mechanical and metallurgical characteristics of continuous wave CO2 laser welded dissimilar couple of AISI 304 stainless steel and [...]
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Friction and wear behavior of nitrogen-doped ZnO thin films deposited via MOCVD under dry contact
U. Mbamara, B. Olofinjana, O. Ajayi, C. Lorenzo-Martin, E. Obiajunwa, E. Ajayi

Collection of Engineering Science and Technology, an International Journal (2017).

Abstract
Most researches on doped ZnO thin films are tilted toward their applications in optoelectronics and semiconductor devices. Research on their tribological properties is still unfolding. In this work, nitrogen-doped ZnO thin films were deposited on 304 L stainless steel substrate from a combination of zinc acetate and ammonium acetate precursor by MOCVD technique. Compositional and structural studies of the films were done using Rutherford Backscattering Spectroscopy (RBS) and X-ray Diffraction (XRD). The frictional behavior of the thin film coatings was evaluated using a ball-on-flat configuration in reciprocating sliding under dry contact condition. After friction test, the flat and ball counter-face surfaces were examined to assess the wear dimension and failure mechanism. Both friction behavior and wear (in the ball counter-face) were observed to be dependent on the crystallinity and thickness of the thin film coatings.
Abstract
Most researches on doped ZnO thin films are tilted toward their applications in optoelectronics and semiconductor devices. Research on their tribological properties is still [...]
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Multi-objective optimized fuzzy-PID controllers for fourth order nonlinear systems
M. Mahmoodabadi, H. Jahanshahi

Collection of Engineering Science and Technology, an International Journal (2017).

Abstract
In this paper, the Multi-objective Genetic Algorithm (MOGA) is used to obtain the Pareto frontiers of conflicting objective functions for the fuzzy-Proportional-Integral-Derivative (fuzzy-PID) controllers. The ball–beam and inverted pendulum fourth order nonlinear systems are regarded as nonlinear benchmarks. The considered objective functions for the ball–beam system are the distance error of the ball, the angle error of the beam, and the control effort. For the inverted pendulum system, the objective functions are the distance error of the cart, the angle error of the pendulum, and the control effort, which must be minimized simultaneously. The Pareto fronts are compared with those obtained by Multi-objective Particle Swarm Optimization (MOPSO). Four points are chosen from nondominated solutions of the obtained Pareto fronts based on the three conflicting objective functions and used for illustration of the state variables of the controlled systems. Obtained results elucidate the efficiency of the proposed controller in order to control nonlinear systems.
Abstract
In this paper, the Multi-objective Genetic Algorithm (MOGA) is used to obtain the Pareto frontiers of conflicting objective functions for the fuzzy-Proportional-Integral-Derivative [...]
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A hybrid press system: Motion design and inverse kinematics issues
M. Kütük, L. Dülger

Collection of Engineering Science and Technology, an International Journal (2017).

Abstract
A hybrid machine (HM) is a system integrating two types of motor, servo and constant velocity with a mechanism. The purpose is to make use of the energy in the system efficiently with a flexible system having more than one degree of freedom (DOF). A review is included on hybrid press systems. This study is included as a part of an industrial project used for metal forming. The system given here includes a 7 link mechanism, one of link is driven by a constant velocity motor (CV) and the other is driven by a servo motor (SM). Kinematics analysis of the hybrid driven mechanism is presented here as inverse kinematics analysis. Motion design is very crucial step when using a hybrid machine. So motion design procedure is given with motion curve examples needed. Curve Fitting Toolbox (CFT) in Matlab® is offered as an auxiliary method which can be successfully applied. Motion characteristics are chosen by looking at requirements taken from metal forming industry. Results are then presented herein.
Abstract
A hybrid machine (HM) is a system integrating two types of motor, servo and constant velocity with a mechanism. The purpose is to make use of the energy in the system efficiently [...]
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Design of microstrip-fed printed UWB diversity antenna with tee crossed shaped structure
R. Kumar, G. Surushe

Collection of Engineering Science and Technology, an International Journal (2017).

Abstract
A compact, Ultra Wideband (UWB) antenna system for multi-input multi-output (MIMO)/diversity application is proposed. The antenna system is a microstrip structure with two similar triangular shaped radiating elements and a common ground plane. The radiating elements are excited by tapered feed for better impedance matching. A T-crossed shaped stub is added in the ground plane to increase the isolation between the two radiators. The overall dimension of the proposed antenna system is 46 mm × 32.6 mm × 1.6 mm. The measured impedance bandwidth (reflection coefficient < −10 dB) is from 1.8 GHz to well beyond 12 GHz which covers the entire UWB region. A measured isolation of 15 dB or better is achieved in the UWB region. The diversity gain of the antenna system is close to 10 dBi and the envelope correlation coefficient is well below 0.2 in the operating band. Parametric study is also done to check the sensitivity of the antenna in terms of reflection coefficient and isolation to the different parameters. These characteristics show that the proposed antenna is suitable for the MIMO/diversity application.
Abstract
A compact, Ultra Wideband (UWB) antenna system for multi-input multi-output (MIMO)/diversity application is proposed. The antenna system is a microstrip structure with two [...]
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Analysis of low mutual coupling compact multi-band microstrip patch antenna and its array using defected ground structure
M. Kumar, V. Nath

Collection of Engineering Science and Technology, an International Journal (2017).

Abstract
In this paper, a simple microstrip patch antenna and a two-element E-plane coupled microstrip antenna array employing a defected ground structure are investigated. Without defected ground structure, the antenna has an impedance bandwidth of 675 MHz (6.78% at the center frequency of 9.955 GHz) and a gain of around 4.38 dB. The performance of the microstrip antenna in terms of impedance bandwidth, matching performance, gain and return loss can be improved by introducing a defect in the ground plane. As a result of which, bandwidth of 1.652 GHz (16.42% at the center frequency of 10.06 GHz) and a gain of 8.96 dB along with 5 different other operating bands are achieved. After integrating the microstrip antenna with the proposed defected ground structure, effective footprint of the antenna is reduced up to 66.95%. When integrated with proposed DGS array, the same antenna array structure shows miniaturization up to 78.97%. The proposed defected ground structure when compared to other techniques shows an exceptionally lower mutual coupling between two E-plane coupled microstrip antenna elements.
Abstract
In this paper, a simple microstrip patch antenna and a two-element E-plane coupled microstrip antenna array employing a defected ground structure are investigated. Without [...]
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Exploration of waste cooking oil methyl esters (WCOME) as fuel in compression ignition engines: A critical review
S. Kathirvel, A. Layek, S. Muthuraman

Collection of Engineering Science and Technology, an International Journal (2017).

Abstract
The ever growing human population and the corresponding economic development of mankind have caused a relentless surge in the energy demand of the world. The fast diminishing fossil fuel reserves and the overdependence of petroleum based fuels have already prompted the world to look for alternate sources of energy to offset the fuel crisis in the future. Waste Cooking Oil Methyl Ester (WCOME) has proven itself as a viable alternate fuel that can be used in Compression Ignition (CI) engines due to its low cost, non-toxicity, biodegradability and renewable nature. It also contributes a minimum amount of net greenhouse gases, such as CO2, SO2 and NO emissions to the atmosphere. The main objective of this paper is to focus on the study of the performance, combustion and emission parameters of CI engines using WCOME and to explore the possibility of utilizing WCOME blends with diesel extensively in place of diesel. The production methods used for transesterification play a vital role in the physiochemical properties of the methyl esters produced. Various production intensification technologies such as hydrodynamic cavitation and ultrasonic cavitation were employed to improve the yield of the methyl esters during transesterification. This review includes the study of WCOME from different origins in various types of diesel engines. Most of the studies comply with the decrease in carbon monoxide (CO) emissions and the increase in brake thermal efficiency while using WCOME in CI engines. Many researchers reported slight increase in the emissions of oxides of nitrogen. ANN modeling has been widely used to predict the process variables of the diesel engine while using WCOME. The versatility of ANN modeling was proven by the minimum error percentages of the actual and predicted values of the performance and emission characteristics.
Abstract
The ever growing human population and the corresponding economic development of mankind have caused a relentless surge in the energy demand of the world. The fast diminishing [...]
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