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دسترسی آزاد مقاله
1 - Measuring The Quality of Natural Lighting in A Building with Double Skin Façade (DSF)
A. E. Manubawa LMF Purwanto A. ArdiyantoLately, a double skin façade (DSF) has been increasingly popular as an aesthetic and shading device. A façade with a secondary skin is employed in buildings to let natural light flow into the building without glare and heat. The purpose of this study is to چکیده کاملLately, a double skin façade (DSF) has been increasingly popular as an aesthetic and shading device. A façade with a secondary skin is employed in buildings to let natural light flow into the building without glare and heat. The purpose of this study is to examine the performance of secondary skin in buildings and to investigate the level of natural lighting in buildings that meets visual comfort standards according to the function of space in buildings. The object of this research is the Henricus Constant building of Soegijapranata Catholic University Semarang Indonesia. The research method used is descriptive quantitative. The authors assessed the level of natural lighting in the building by analyzing the results of field measurement data with luxmeter measuring devices and model simulations regarding natural shadows and lighting levels with Sketchup software and dialux. The results of this study suggest that secondary skins in the Henricus Constant building manage to create shade in the building’s interior, but the natural lighting level is only 30 lux, less than the standard lighting level of the classroom at 250 lux. Without the secondary skin, the average light intensity is 310 lux; thus, it causes glare and becomes visually uncomfortable. پرونده مقاله -
دسترسی آزاد مقاله
2 - Utilizing Computer Simulation and DEAGP to Enhance Productivity in a Manufacturing System
B. Vaisi A. EbrahimiGenerally, a typical problem which is crucial in a manufacturing system is increasing the production rate. To cope with the problem, different types of techniques are used in companies by trial and error which imposes high costs on them. Using simulation as a tool for a چکیده کاملGenerally, a typical problem which is crucial in a manufacturing system is increasing the production rate. To cope with the problem, different types of techniques are used in companies by trial and error which imposes high costs on them. Using simulation as a tool for assessing the effect of alterations on the performance of the overall system might be significant. This paper considers a simulation based data envelopment analysis goal programming (DEAGP) applied into a well-known automobile spare part manufacturer in Kurdistan to improve production rate. The objective is to develop a simulation model based on real system to identify the imbalances and improve the performance of production system. For this purpose, in 2013 data are collected from existing system and applying full factorial design of experiments technique, different scenarios have been considered then to find the best one we used data envelopment analysis goal programming technique as a method for measuring the relative efficiency of similar units. The results show that, the optimum scenarios are 5 and 8. Applying this method could conduct us to gain more than 1% improvement in production rate using the existing resources. پرونده مقاله -
دسترسی آزاد مقاله
3 - تعیین زاویه تمایل بهینه برای روشنایی طبیعی آتریوم در تهران بر اساس زوایای خورشید و ویژگی‌های اقلیمی
علیرضا باقری محمدعلی خانمحمدی هانیه صنایعیانزمینه و هدف: نور روز تاثیر مثبتی بر سلامتی افراد، بهره‌وری کارمندان و ارزندگی املاک دارد. لیکن با افزایش بلندمرتبه سازی در شهر‌های پرجمعیت، دسترسی طبقات تحتانی به روشنایی طبیعی با چالش‌هایی همراه است. آتریوم یکی از استراتژی‌های تامین نور طبیعی برای طبقات تحتانی است. عمل چکیده کاملزمینه و هدف: نور روز تاثیر مثبتی بر سلامتی افراد، بهره‌وری کارمندان و ارزندگی املاک دارد. لیکن با افزایش بلندمرتبه سازی در شهر‌های پرجمعیت، دسترسی طبقات تحتانی به روشنایی طبیعی با چالش‌هایی همراه است. آتریوم یکی از استراتژی‌های تامین نور طبیعی برای طبقات تحتانی است. عملکرد روشنایی طبیعی آتریوم قبل از ساخت به لطف شبیه سازی رایانه‌ای قابل ارزیابی است. تا پیش از این، شبیه سازی نور روز تنها محدود به شرایط آسمان ابری بود. لیکن با روش‌های جدید شبیه سازی رایانه‌ای نور روز، می‌توان متغیر‌های وضعیت خورشید و شرایط آسمان را در طول یکسال و در تمام ساعات روز بررسی کرد. این پیشرفت اعمال مولفه‌ی نور مستقیم خورشید در شبیه سازی ممکن کرده و در نتیجه امکان بررسی تاثیر شاخصه‌هایی از معماری که با جهت نور مستقیم در ارتباط هستند فراهم شده است. با توجه به نکته فوق، این پژوهش بر تاثیر زاویه تمایل دیوار‌های داخلی آتریوم بر روشنایی اتاق‌های مجاور آن تمرکز دارد.روش بررسی: زوایای مختلف آتریوم، در جهت شمال و جنوب به روش "مدل سازی روشنایی طبیعی مبتنی بر اقلیم" برای شهر تهران بررسی شده‌اند. از معیار‌های سنجش روشنایی طبیعی sDA، ASE و UDI برای انجام شبیه سازی‌های رایانه‌ای استفاده شده است.یافته‌ها: متمایل شدن جداره‌های داخلی آتریوم با زاویه 20 درجه به سمت جنوب باعث بهبود هر سه معیار ذکر شده در طبقات تحتانی آتریوم می‌شود. لیکن تمایل دیوار‌های آتریوم به سمت شمال، علاوه بر تاثیر نامطلوب بر روشنایی طبقات پایین، در طبقات بالا نیز خیرگی را افزایش می‌دهد.بحث و نتیجه گیری: اگرچه تاثیر زاویه تمایل بر عملکرد روشنایی طبیعی آتریوم به برجستگی سایر عوامل نیست، با این حال طراح می‌تواند در مراحل اولیه طراحی، به کمک چیدمان صحیح و الویت بندی مناسب فضاها برای بهره گیری از روشنایی طبیعی، این تاثیر را به حداکثر برساند. پرونده مقاله -
دسترسی آزاد مقاله
4 - Evaluation of Breast Tumor with Antipodal Vivaldi Antenna
Emine AVŞAR AYDINSubsurface scanning problems, which both it is one of microwave imaging techniques and there are applications in various fields, has become a very interesting topic today. Many methods have been developed to detect cancer cells. The electrical properties of malignant ca چکیده کاملSubsurface scanning problems, which both it is one of microwave imaging techniques and there are applications in various fields, has become a very interesting topic today. Many methods have been developed to detect cancer cells. The electrical properties of malignant cancer cells compared to normal cells indicate significant differences at microwave frequencies. Since breast tissue according to such as brain and muscle tissues is permeable than these tissues, this case supports the idea of imaging of cancerous cells in the microwave range. Various techniques such as mammography for breast cancer diagnosis are inadequate in detecting malignant cells, have high cost, and also patients are exposed harmful rays. Because of these, it is not a desirable situation. Therefore, non-ionizing electromagnetic waves used to detect cancerous cells in the human body has been widely used in biomedical applications nowadays. In this paper, both an antipodal Vivaldi antenna with enhanced bandwidth and a 3D breast structure which has different permittivity and conductivity is modelled in CST software simulation tool to solve electromagnetic field values. Return loss, VSWR, and radiation pattern characteristics which are significant antenna parameters are simulated and obtained whether the antenna possess an efficient characteristic or not. Also, electric field values over the breast tissue with tumor and without tumor are evaluated. پرونده مقاله -
دسترسی آزاد مقاله
5 - Analysing the Climatic Impact of Central Courtyards in Traditional Houses of Tabriz
Sasan Moradi Mehrdad Matin Rima FayazAs an inseparable organ, courtyards have influenced the history of architecture with their presence in the context of constructed sites and in a wider sense (architecture), it has provided permissive answers to numerous aspects of climatic, cultural and security demands چکیده کاملAs an inseparable organ, courtyards have influenced the history of architecture with their presence in the context of constructed sites and in a wider sense (architecture), it has provided permissive answers to numerous aspects of climatic, cultural and security demands of the residents. Discovering different aspects of environmental and climatic function in the central courtyard of the traditional residential structures in the cold regions of the country is the main goal of this research. The main fundamental subject that this research is based on, is “to what extent a closed yard in a region with cold climate can be responsive to the unfavorable climate conditions?” and “to what extent it can protect the residents against the unfavorable climate conditions?” In order to answer the main questions of the research, the traditional courtyard houses in the city of Tabriz are selected as the case studies. The methodology of this study is quantitative. Through comparative analysis, the samples were used based on the outdoor thermal comfort criteria using simulation software. ENVI-met numerical modeling method and the Rayman software model were employed. For this purpose, the PMV and PET indices are calculated and analyzed as the measure for estimating thermal comfort indices in the open spaces and also other indices including air temperature, mean radiant temperature, relative humidity, and wind speed that influences the thermal comfort. The results indicate that according to the PMV and PET indices, courtyards and their adjacent open spaces will be set outside of the comfort zone, especially during the winter, and closed yards does not possess the capability of thermal improvement in comparison to the exterior open spaces. Also, results of the study indicates that, by decreasing the area of the courtyards and the surrounding walls along with the increase of the shaded areas, we are not only limiting the possibility of ventilation in the summer but, this will also decrease the amount of passive heat storage in the surfaces of courtyards in the cold seasons. As the most important accomplishment of this research we can focus on the fact that physical specifications of traditional houses with courtyards in Tabriz do not possess a climatic approach, and the central courtyards in this region are elements which are subordinate to the historical, social and cultural or safety roles of them . پرونده مقاله -
دسترسی آزاد مقاله
6 - Finding the Best Orientation of the Educational Buildings in Hot Arid Regions in Iran, in order to achieve theOptimum Annual Energy Consumption, Using Computer Simulation (Case Study: a Double Class School in Zahedan)
Hamid Aibaghi Esfahani Kourosh Momeni Faramarz Hassan PourSchool buildings forming a large part of the public buildings, are among the most important consumers of energy in Iran. Given the existing construction conditions, these buildings seem to have considerable potential for energy efficiency if the construction and design چکیده کاملSchool buildings forming a large part of the public buildings, are among the most important consumers of energy in Iran. Given the existing construction conditions, these buildings seem to have considerable potential for energy efficiency if the construction and design methods are reformed. Therefore, numerous researchers have analyzed geometrical factors influencing energy consumption in buildings, but few researchers have specifically and precisely studied building orientation. In this research, a two-classroom school with a simple and extendable plan, typical of hot and arid regions in Iran was studied. The objective is to conclude optimum orientation for minimum energy demand, taking into consideration the provision of a thermally comfortable environment inside. Building performance simulation (using Design Builder software) was applied to support design optimization. To this end, 72 models were simulated in different directions with a 5-degree variance, and the 10-degree range of the minimum annual energy consumption was obtained. Afterward, the simulation with the 1-degree variance was repeated using the same range and the results were compared. Finally, it was suggested that the model with the orientation of 109 degrees longitudinal yields the minimum energy consumption. Other methods of saving energy in this region were also discussed. Consequently, the comparison of the results revealed that the effect of building orientation on reducing annual energy consumption in Zahedan is noticeable, considering the number of typical buildings and life span of the buildings. پرونده مقاله -
دسترسی آزاد مقاله
7 - A Comparison of Job-Shop and Group Technology Using Simulation by ARENA
Siyavash Khaledan Hadi ShirouyehzadProduction planning is performed through diverse methods according to the type of the system it is structured upon. One of the most important steps before production planning is to determine which system best fits the firm, and how the facilities should be designed. Bot چکیده کاملProduction planning is performed through diverse methods according to the type of the system it is structured upon. One of the most important steps before production planning is to determine which system best fits the firm, and how the facilities should be designed. Both job-shop and group-technology systems have their own pros and cons, each of which is suitable to a specific kind of factory. On the other hand, performance measurement is also important in terms of both productivity and queue factors. A good method to measure the performance is computer simulation by soft wares such as ARENA. This paper utilizes the software for separately simulating both the job-shop and group-technology systems for specific firm, and then compares the results. The results show that the group-technology system is better than the job-shop system in both productivity and queue factors, and it is highly recommended that the system should be changed. پرونده مقاله -
دسترسی آزاد مقاله
8 - A Nonlinear Mathematical model for Asthma: Effect of Environmental Pollution
NARESHA RAM Agraj TripathiIn this paper, we explore a nonlinear mathematical model to study the spread of asthma due to inhaled pollutants from industry as well as tobacco smoke from smokers in a variable size population. The model is analyzed using stability theory of differential equations and چکیده کاملIn this paper, we explore a nonlinear mathematical model to study the spread of asthma due to inhaled pollutants from industry as well as tobacco smoke from smokers in a variable size population. The model is analyzed using stability theory of differential equations and computer simulation. It is shown that with an increase in the level of air pollutants concentration, the asthmatic (diseased) population increases. It is also shown that along with pollutants present in the environment, smoking (active or passive) also helps in the spread of asthma. Moreover, with the increase in the rate of interaction between susceptibles and smokers, the persistence of the spread of asthma is higher. A numerical study of the model is also performed to see the role of certain key parameters on the spread of asthma and to support the analytical results. پرونده مقاله -
دسترسی آزاد مقاله
9 - The Comparison of Four Economical Selection Indices for Improving the Performance of Kermani Sheep under Rural Production System
N. Kargar Borzi M.S. MokhtariDeveloping effective selection programs for improving the performance of livestock requires taking the economical selection indices into account. The present study was performed for comparing four selection indices developed in Kermani sheep through simulated data. The چکیده کاملDeveloping effective selection programs for improving the performance of livestock requires taking the economical selection indices into account. The present study was performed for comparing four selection indices developed in Kermani sheep through simulated data. The relative importance of traits was determined based on the estimated economic values and consequently, the most beneficial traits were applied to develop the selection indices. The considered selection indices were different combinations of traits including ewe body weight (EBW), annual wool weight (AWW) and total weaning weight of lambs per exposed ewe (TWWEE). The first index included all three mentioned traits (EBW, AWW, and TWWEE). The second, third and fourth indices were included (AWW, TWWEE), (EBW, TWWEE) and (TWWEE), respectively. In general, the obtained results indicated that under all the developed selection indices the aggregate genotype, selection index and economic progress increased by increasing in the population size and decreasing in ram ratio, but resulted in reduced inbreeding average. In more cases, the aggregate genotype decreased by removing a trait from the index. The comparisons among indices indicated that the most suitable selection index for this breed under rural production system is the first index which included EBW, AWW, and TWWEE. This index had a maximum selection index average, aggregate genotype, and economic progress. پرونده مقاله
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