A passive skylight system is a significant building design element that provides an ideal condition for interior spaces. However, the use of this system is limited to specific climatic regions because of its considerable effect on the indoor environment. Malaysia is a tropical country that has favorable natural benefits, such as solar geometry and natural light, which can brighten building interiors throughout the year. However, harnessing this benefit affects spaces, especially those in single-story buildings, because of excessive natural loads. This study reviews a concept to understand the passive behavior of solar radiation in the form of light and heat that falls on, interacts with, and is emitted from a skylight system in a single-story building. The study method is theoretically based on descriptive analysis to assess design requirements. The review shows that designs grounded on the physical aspects of climate (influenced variables), materials (design variables), and human comfort (affected variables) in one process (ESI) can develop the architectural way of thinking rather than estimate the condition based on a limited perspective. This assumption indicates that the adoption of this concept in the preliminary design stage will enable designers to balance the building environment effectively.
Abstract A passive skylight system is a significant building design element that provides an ideal condition for interior spaces. However, the use of this system is limited to specific [...]
Cooling is one of the major concerns in building tropical houses. This problem is exacerbated by the heat gain of the roof, which constitutes 70% of the total heat gain. The passive cooling technique is one of the innovative practices and technologies that provide buildings with comfortable conditions through natural means. Reflective and radiative processes are the methods used to decrease heat gain by facilitating the elimination of excess heat in a building׳s interior to maintain a comfortable environment. Given that the potential of these techniques vary from region to region, their application in the tropics should be examined. Exploring these approaches in detail allows us to rethink how to effectively adapt these techniques to overcome the build-up of heat in modern tropical houses in Southeast Asia. This study reviews the physical characteristics of these approaches to guide architects and building designers. Results indicate a great reduction in operational cost. However, the significant differences in the performance of colour and material properties should be considered, given that the selected approach strongly affects the required thermal conditions of a building.
Abstract Cooling is one of the major concerns in building tropical houses. This problem is exacerbated by the heat gain of the roof, which constitutes 70% of the total heat gain. The [...]
J. García-Espinosa, B. Serván-Camas, P. Ubach, E. Oñate, D. Di-Capua, J. Espinosa
Example of a collection (2017).
Abstract
This paper shows the recent work of the authors in the development of a time-domain FEM model for evaluation of the seal dynamics of a surface effect ship. The fluid solver developed for this purpose, uses a potential flow approach along with a stream-line integration of the free surface. The paper focuses on the free surface-structure algorithm that has been developed to allow the simulation of the complex and highly dynamic behavior of the seals in the interface between the air cushion, and the water.The developed fluid-structure interaction solver is based, on one side, on an implicit iteration algorithm, communicating pressure forces and displacements of the seals at memory level and, on the other side, on an innovative wetting and drying scheme able to predict the water action on the seals. The stability of the iterative scheme is improved by means of relaxation, and the convergence is accelerated using Aitken^s method.Several validations against experimental results have been carried out to demonstrate the developed algorithm.
Abstract This paper shows the recent work of the authors in the development of a time-domain FEM model for evaluation of the seal dynamics of a surface effect ship. The fluid solver [...]
Particle methods in Computational Fluid Dynamics (CFD) are numerical tools for the solution of the equations of f luid dynamics obtained by replacing the fluuid continuum with a finite set of particles. For mathematicians, particles are just points from which properties of the uid can be interpolated. For physicists the particles are material points, which can be treated like any other particle system. Either way, particle methods have a number of attractive features. One of the key attributes is that pure advection is treated exactly. For example, if the particles are given a determined colour and the velocity is specified, the transport of colours by the particle system is exact. The convection of properties also eases the solution of multi material problems, simplifying the detection of interfaces. The use of particles also allows to bridge the gap between the continuum and fragmentation in a natural way, for example in fracture or droplets problems. Since the computation domain, the particles, matches exactly the material domain of interest, the computational resources are optimized with the corresponding reduction in storage and calculation time compared to other methods. Finally, because of the close similarity between particle methods and the physics of the problems to be solved, it is often possible to account for complex physics more easily than with other methods.
Abstract Particle methods in Computational Fluid Dynamics (CFD) are numerical tools for the solution of the equations of f luid dynamics obtained by replacing the fluuid continuum [...]
This article presents the study of structural reinforcement for a building of educational use, known as "Old Type II". The school was built before the creation of the Venezuelan SeismoresistantCovenin 1756. The results of the structural analysis showed insufficient responsiveness to service requests, high vulnerability to seismic action and deficiencies in the quantity and distribution of reinforcing steel. For this reason, the reinforcement of the superstructure was proposed by the construction of panel walls, verifying their action on the existing piloting system. For the modeling, the values of resistance of the concrete obtained in the destructive tests made by the materials laboratory of the School of Civil Engineering of the Universidad Centroccidental Lisandro Alvarado and the soil parameters from the geotechnical study were used.
Abstract This article presents the study of structural reinforcement for a building of educational use, known as "Old Type II". The school was built before the creation of the Venezuelan [...]
The construction industry is considered as one of the industries with lower yields, frequent delays and reprogramming. Due to this and to avoid losses of time, costs and inconveniences in the execution, the virtual construction is used, that allows to analyze previously the constructive sequences and the possible interferences between the different activities through a real time scenary according to the programmed schedule . This article shows the implementation of BIM technology in a modular housing development in Venezuela. Four 4D simulations were carried out, two initially due to the original planning and its timely improvement, and two subsequent corresponding to reprogramming due to actual delays in execution due to lack of concrete supply. The main results were: problems of programming logic, interferences between activities, unreal sequences, among others in the first models. As for the models of the reprogramming gave resulting times very similar to reality; This means that the models work both in ideal situations and in situations of uncertainty. Building information modeling solutions introduce a new way of working, based on the creation and use of coherent and coordinated information, wich allows for faster decision making, better documentation and the possibility of predicting the drawbacks Even before the work began.
Abstract The construction industry is considered as one of the industries with lower yields, frequent delays and reprogramming. Due to this and to avoid losses of time, costs and inconveniences [...]
This paper presents a new computational technique for predicting the onset and evolution of fracture in a continuum in a simple manner combining the finite element method (FEM) and the discrete element method (DEM). Once a crack is detected at an element side in the FE mesh, discrete elements are generated at the nodes sharing the side and a simple DEM mechanism is considered to follow the evolution of the crack. The combination of the DEM with simple 3-noded linear triangular elements correctly captures the onset of fracture and its evolution, as shown in several examples of application in two and three dimensions.
Abstract This paper presents a new computational technique for predicting the onset and evolution of fracture in a continuum in a simple manner combining the finite element method [...]
La caracterización de acuíferos es un problema fundamental en Geohidrología. El problema consiste en estimar los parámetros fenomenológicos a partir de datos de alturas piezométricas. Los datos de campo son obtenidos en pozos de observación los cuales son pocos y dispersos en el acuífero. En este trabajo proponemos una solución al problema de estimación en dos partes. Primero utilizamos un método de interpolación con funciones de base radial para generar datos suficientes de alturas piezométricas, después aplicamos el método del sistema diferencial para la estimación de parámetros. Mostramos la aplicabilidad del método en una caracterización del acuífero Silao-Romita en Guanajuato México. Summary Aquifer characterization is an important problem in Geohidrology. The problem consits in estimating phenomenological parameters given piezometric data. In general eld data is obtained in observation wells, which are few and scattered in the aquifer. In this work we propose a solution to the problem of parameter estimation in two parts. First we use an interpolation technique by means of radial basis functions to generate suffcient piezometric data, then we apply the Differential System method for parameter estimation. To illustrate the method, we show a characterization of the Silao-Romita aquifer located in Guanajuato Mexico.
Abstract La caracterización de acuíferos es un problema fundamental en Geohidrología. El problema consiste en estimar los parámetros fenomenológicos a partir de datos de alturas [...]
Extensive consumer exposure to food- and cosmetics-related consumer products containing nanosilver is of public safety concern. Therefore, there is a need for suitable in vitro models and sensitive predictive rapid screening methods to assess their toxicity. Toxicogenomic profile showing subtle changes in gene expressions following nanosilver exposure is a sensitive toxicological endpoint for this purpose. We evaluated the Caco2 cells and global gene expression profiles as tools for predictive rapid toxicity screening of nanosilver. We evaluated and compared the gene expression profiles of Caco-2 cells exposed to 20 nm and 50 nm nanosilver at a concentration 2.5 μg/ml. The global gene expression analysis of Caco2 cells exposed to 20 nm nanosilver showed that a total of 93 genes were altered at 4 h exposure, out of which 90 genes were up-regulated and 3 genes were down-regulated. The 24 h exposure of 20 nm silver altered 15 genes in Caco2 cells, out of which 14 were up-regulated and one was down-regulated. The most pronounced changes in gene expression were detected at 4 h. The greater size (50 nm) nanosilver at 4 h exposure altered more genes by more different pathways than the smaller (20 nm) one. Metallothioneins and heat shock proteins were highly up-regulated as a result of exposure to both the nanosilvers. The cellular pathways affected by the nanosilver exposure is likely to lead to increased toxicity. The results of our study presented here suggest that the toxicogenomic characterization of Caco2 cells is a valuable in vitro tool for assessing toxicity of nanomaterials such as nanosilver.
Abstract Extensive consumer exposure to food- and cosmetics-related consumer products containing nanosilver is of public safety concern. Therefore, there is a need for suitable in [...]
The constant discharge of agricultural waste into aquatic environment has led to accumulation of heavy chemicals and other variety of pollutants. Herbicides present in these wastes are washed down, carried by rains and flood to nearby aquatic environment. Glyphosate is one of the most popular herbicides used by farmers in Kano because of its active reaction on killing weeds without affecting the crops. A toxicity test of glyphosate was conducted using concentrations of 0, 0.004, 0.005, 0.006, 0.007 ml/l. The mortality rate of each concentration was determined and the physicochemical parameters (Dissolved oxygen and pH) were also determined. The result showed that high mortality occurs at 0.007 ml/l and less mortality was found at 0.004 ml/l. Hence, mortality is dose dependent. DO and pH decreases with increase in glyphosate concentration. Furthermore, the juveniles showed abnormal behaviour. The LC50 value at 96 h was 0.0072 ml/l. There was significant difference between the initial and final pH value (p < 0.05). On the other hand, the initial and final DO values showed no significant difference (p > 0.05). However, correlation between DO and pH showed no significant difference (p > 0.05). The findings of this study established that glyphosate has some level of toxicity on Clarias gariepinus juveniles. In addition, it was found that mortality, changes in behaviour, DO and pH are dose dependent. Therefore, it was suggested that an appropriate concentration that will not be detrimental to non-target organisms should be used by farmers. Alternatively, Biological method should be used as a substitute for chemical method of controlling weeds.
Abstract The constant discharge of agricultural waste into aquatic environment has led to accumulation of heavy chemicals and other variety of pollutants. Herbicides present in these [...]
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec vitae ante neque. Maecenas vestibulum velit tellus, consequat consequat lectus maximus et. Nulla eleifend risus eu elit porta, et mollis dui auctor. Fusce vitae ligula augue. Nulla facilisi. Nunc ac erat volutpat, pharetra lorem quis, ornare ipsum. In in eros felis. Maecenas porttitor ex at metus iaculis faucibus. Cras dictum condimentum leo, in congue eros laoreet ac. Etiam eget mattis quam. Morbi dignissim imperdiet tortor, quis porttitor erat dictum at. In non enim nec erat eleifend dictum at quis ipsum. Donec a diam ac arcu laoreet finibus. Ut non elementum odio.
In cursus eget risus nec posuere. Aliquam tincidunt at massa eget accumsan. Praesent ut gravida enim. Ut non aliquam justo. Morbi eu nisi ac elit pellentesque blandit nec eget ex. Duis tempus congue mi, nec varius dolor porta euismod. Vestibulum rutrum quis augue nec varius. Sed porta euismod enim, ac suscipit lacus egestas eu. Pellentesque hendrerit purus velit, rutrum faucibus augue laoreet sed. Fusce risus urna, interdum et mattis in, commodo nec lectus. Mauris et bibendum magna. Fusce porta feugiat tortor eget fringilla. Cras iaculis non magna in vulputate. Cras volutpat finibus mi, id convallis augue consectetur vel. Quisque convallis.
Abstract Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec vitae ante neque. Maecenas vestibulum velit tellus, consequat consequat lectus maximus et. Nulla eleifend risus [...]
Particle methods in Computational Fluid Dynamics (CFD) are numerical tools for the solution of the equations of f luid dynamics obtained by replacing the fluuid continuum with a finite set of particles. For mathematicians, particles are just points from which properties of the uid can be interpolated. For physicists the particles are material points, which can be treated like any other particle system. Either way, particle methods have a number of attractive features. One of the key attributes is that pure advection is treated exactly. For example, if the particles are given a determined colour and the velocity is specified, the transport of colours by the particle system is exact. The convection of properties also eases the solution of multi material problems, simplifying the detection of interfaces. The use of particles also allows to bridge the gap between the continuum and fragmentation in a natural way, for example in fracture or droplets problems. Since the computation domain, the particles, matches exactly the material domain of interest, the computational resources are optimized with the corresponding reduction in storage and calculation time compared to other methods. Finally, because of the close similarity between particle methods and the physics of the problems to be solved, it is often possible to account for complex physics more easily than with other methods.
Abstract Particle methods in Computational Fluid Dynamics (CFD) are numerical tools for the solution of the equations of f luid dynamics obtained by replacing the fluuid continuum [...]
This paper presents a new computational technique for predicting the onset and evolution of fracture in a continuum in a simple manner combining the finite element method (FEM) and the discrete element method (DEM). Once a crack is detected at an element side in the FE mesh, discrete elements are generated at the nodes sharing the side and a simple DEM mechanism is considered to follow the evolution of the crack. The combination of the DEM with simple 3-noded linear triangular elements correctly captures the onset of fracture and its evolution, as shown in several examples of application in two and three dimensions.
Abstract This paper presents a new computational technique for predicting the onset and evolution of fracture in a continuum in a simple manner combining the finite element method [...]
This article presents the study of structural reinforcement for a building of educational use, known as "Old Type II". The school was built before the creation of the Venezuelan SeismoresistantCovenin 1756. The results of the structural analysis showed insufficient responsiveness to service requests, high vulnerability to seismic action and deficiencies in the quantity and distribution of reinforcing steel. For this reason, the reinforcement of the superstructure was proposed by the construction of panel walls, verifying their action on the existing piloting system. For the modeling, the values of resistance of the concrete obtained in the destructive tests made by the materials laboratory of the School of Civil Engineering of the Universidad Centroccidental Lisandro Alvarado and the soil parameters from the geotechnical study were used.
Abstract This article presents the study of structural reinforcement for a building of educational use, known as "Old Type II". The school was built before the creation of the Venezuelan [...]
The construction industry is considered as one of the industries with lower yields, frequent delays and reprogramming. Due to this and to avoid losses of time, costs and inconveniences in the execution, the virtual construction is used, that allows to analyze previously the constructive sequences and the possible interferences between the different activities through a real time scenary according to the programmed schedule . This article shows the implementation of BIM technology in a modular housing development in Venezuela. Four 4D simulations were carried out, two initially due to the original planning and its timely improvement, and two subsequent corresponding to reprogramming due to actual delays in execution due to lack of concrete supply. The main results were: problems of programming logic, interferences between activities, unreal sequences, among others in the first models. As for the models of the reprogramming gave resulting times very similar to reality; This means that the models work both in ideal situations and in situations of uncertainty. Building information modeling solutions introduce a new way of working, based on the creation and use of coherent and coordinated information, wich allows for faster decision making, better documentation and the possibility of predicting the drawbacks Even before the work began.
Abstract The construction industry is considered as one of the industries with lower yields, frequent delays and reprogramming. Due to this and to avoid losses of time, costs and inconveniences [...]
A passive skylight system is a significant building design element that provides an ideal condition for interior spaces. However, the use of this system is limited to specific climatic regions because of its considerable effect on the indoor environment. Malaysia is a tropical country that has favorable natural benefits, such as solar geometry and natural light, which can brighten building interiors throughout the year. However, harnessing this benefit affects spaces, especially those in single-story buildings, because of excessive natural loads. This study reviews a concept to understand the passive behavior of solar radiation in the form of light and heat that falls on, interacts with, and is emitted from a skylight system in a single-story building. The study method is theoretically based on descriptive analysis to assess design requirements. The review shows that designs grounded on the physical aspects of climate (influenced variables), materials (design variables), and human comfort (affected variables) in one process (ESI) can develop the architectural way of thinking rather than estimate the condition based on a limited perspective. This assumption indicates that the adoption of this concept in the preliminary design stage will enable designers to balance the building environment effectively.
Abstract A passive skylight system is a significant building design element that provides an ideal condition for interior spaces. However, the use of this system is limited to specific [...]
Cooling is one of the major concerns in building tropical houses. This problem is exacerbated by the heat gain of the roof, which constitutes 70% of the total heat gain. The passive cooling technique is one of the innovative practices and technologies that provide buildings with comfortable conditions through natural means. Reflective and radiative processes are the methods used to decrease heat gain by facilitating the elimination of excess heat in a building׳s interior to maintain a comfortable environment. Given that the potential of these techniques vary from region to region, their application in the tropics should be examined. Exploring these approaches in detail allows us to rethink how to effectively adapt these techniques to overcome the build-up of heat in modern tropical houses in Southeast Asia. This study reviews the physical characteristics of these approaches to guide architects and building designers. Results indicate a great reduction in operational cost. However, the significant differences in the performance of colour and material properties should be considered, given that the selected approach strongly affects the required thermal conditions of a building.
Abstract Cooling is one of the major concerns in building tropical houses. This problem is exacerbated by the heat gain of the roof, which constitutes 70% of the total heat gain. The [...]
J. García-Espinosa, B. Serván-Camas, P. Ubach, E. Oñate, D. Di-Capua, J. Espinosa
Example of a collection (2017).
Abstract
This paper shows the recent work of the authors in the development of a time-domain FEM model for evaluation of the seal dynamics of a surface effect ship. The fluid solver developed for this purpose, uses a potential flow approach along with a stream-line integration of the free surface. The paper focuses on the free surface-structure algorithm that has been developed to allow the simulation of the complex and highly dynamic behavior of the seals in the interface between the air cushion, and the water.The developed fluid-structure interaction solver is based, on one side, on an implicit iteration algorithm, communicating pressure forces and displacements of the seals at memory level and, on the other side, on an innovative wetting and drying scheme able to predict the water action on the seals. The stability of the iterative scheme is improved by means of relaxation, and the convergence is accelerated using Aitken^s method.Several validations against experimental results have been carried out to demonstrate the developed algorithm.
Abstract This paper shows the recent work of the authors in the development of a time-domain FEM model for evaluation of the seal dynamics of a surface effect ship. The fluid solver [...]