Sharif Digital Repository

Environmental conditions of various cities of Iran are deteriorating due to various contributing effects of increased traffic, deforestation, industrial pollution etc. Arak is an example in point. It is a city of about 440,000 inhabitants. It is located at the edge of the main central desert (Kavir) of Iran. It lacks any appreciable vegetation or wooded areas and it is the home of a number of major industries. These include aluminum smelting, petrochemical industry, refinery, power plant and various other heavy manufacturing facilities. It was suggested to perform an air sampling of the city for a whole year (2010-2011) to determine the concentration of various elements by instrumental... 

Method of Prompt Gamma Neutron Activation Analysis (PGNAA) is useful for controlling some massive production processes such as cement industry and mineral materials. Difficulty of other methods of analysis such as XRF comparing with PGNAA is that mass of sample is small and it doesn’t determine heterogeneity of mixture. On the other hand, need to sampling is also another problem of these analysis methods because sampling is terminated and it doesn’t supervise on production continuously, in fact its quality can’t be revealed simultaneously and there is a long time between sampling and control of process. Usually, analysis methods such as XRF are useful for processes that are controlled... 

City of Karaj with 2 million population used to enjoy very clean and accommodating air and environment . This congenial condition was due to agricultural and gardening activities of the local population . This way of life has undergone a profound change due to a change in the economic activities of the local population from farming and agriculture to industrial activities . And this has brought particulate matter wich has been exacerbated in the recent years . With the additional onslaught of the dust storms coming from the neighboring countries due to drying up of rivers and lagoons .The main object of this work was to obtain the spectrum of the PM and the additional component of PM that... 

Ionizing radiation can modify physical, chemical and biological properties of the irradiated materials. At present, the principal industrial applications of radiation are sterilization of health care products including pharmaceuticals, irradiation of food and agriculture products and materials modification. In the above application the wide range of the required doses together with different product densities require spatial mechanical design of the irradiators to be able to properly handle the specified tasks. In the multipurpose irradiators the design of system and positioning of the source must be done in such a way that a nearly optimum dose distaition in the product boxes in... 

Maintenance is one of the most important factors increating an efficient and stable structure intheindustry. Therefore, having an efficient and effective system in this case is very important. In this regard, the Preventive Maintenance Program is considered asone of the most important factors in the productivity and efficiency of machines and manpower.Therefore, designing this system forthemachining zone of Iran Khodro Peugeot 405 Engine Manufacturing hall # 2can have further Improvement In the Efficiency of the plant.
The project was carriedout through the following steps:
- Research and data collection
- Classifying and organizing
- Implementation
In the first step... 

Distributed generation (DG) technologies have achieved an intense progress during the last years. One of the appropriate ways to enter a DG system in the electrical network is through the use of microgrids. Because the majority of DG units are connected to the grid with power electronic converters, specific control strategies have been developed for these converters. Control strategies of DGs in microgrid differ in the grid-connected and the islanded states of operation. Changing the control modes from one state to another requires a reliable islanding detection method, and results in unwanted transients. It is, therefore, desirable to devise an integrated control approach for both states.... 

Gamma irradiation systems are used extensively in the industry in order to sterilize medical devices, disinfect hygienic materials or increase the shelf life of agricultural produce. The method of gamma irradiation is superior to the older methods of heat or chemical treatment because it is by far a simpler operation. In this method only a single parameter of time is controlled whereas in the other mentioned methods five or six different parameters need to be controlled. The design of irradiation systems including the size, location of products and arrangement of source rack pencils. In order to optimize the design it is needed to study the products dose distribution in a wide range of... 

Regarding high importance of casing pipes in oil industry also considering that they have not been producing domestically (with specific features), the main object of this research is feasibility study of establishment of a casing pipe threading plant which produces such kind of pipes. Usage of Casing PipesIs defining as a separator between wall of oil well and its core. The operation starts with driving and fixing a casing pipe to the oil well to avoid its collapsing during excavation process , then next casing pipes will be driven to the well and will be fixed to the previous pipes. During current research, after gathering all related financial and technical data, evaluation of “Net... 

Information and communications technologies have affected the human world rapidly, which challenges the facing today’s information society. Extensive use and impact of these technologies in different aspects of human life have led to an information revolution. This revolution, changes in our understanding of the human nature and physical world. The human is an information organism among the other agents which is living in the informational environment, that is called the infosphere. Moreover, the information revolution has caused to emerge of “Bitcoin”; a phenomenon that is changing economic relations. Bitcoin is a “crypto-currency” and “encrypted payment system” that relying on a... 

Social Studies of Science have been taken seriously for some decade recently. The need to these studies after Kuhn is felt in “ The Structure of Scientific Revolution”. One of these approach, allocating to social studies of Scientific Institution, is the so called approach social constructivism. Followers of this approach take Science and scientific discoveris some kind of the Social Constructivism of scintists. Bruno Latour is one of the most famous theorisian of this approach. Studing the laboratory practies, Latour is tring to know about the bihaviour and interaction of scientists. The result of this endivour is “Laboratory Life”, the grand book. Latour is the famous person in the field... 

This article investigate about Susan George’s ideas concerning the relation of religion and technology and examine her point of view. George, searches synergy between religion and technology and tries to develop basis of artificial intelligence by religion. She provide answers to some philosophical concerns about technology through religion and tries to prove that technological morality needs religion. We show that some of her Assumptions is not through her conclusions. George, notices to the help of technology to religion for providing a new expression. We examine her clams about relation between technology and Islam  

Science and technology, in current century, has taken an unprecedented step towards human-engineering, in which the enhancement of human capacities, states, emotions, and behaviours is taken under consideration. In search of a better world and a happier life, the enhancement technologies aim at the design and development of a better human being. On the other hand, the nexus between the betterment of human nature and the achievement of happiness in life has roots in the traditional virtue theory as well. Virtue ethics also aims at the cultivation of intellectual, moral, and practical capacities of human being. This dissertation is a compare-contrast analysis of the relationship between the... 

In this thesis, a new wind turbine scheme based on Electrically-Excited Synchronous Generator (EESG) and diode-bridge rectifier is proposed and developed. This new scheme is mainly based on the idea of generator excitation current employment as a means of wind turbine control. That is why the new scheme is called Excitation Controlled Synchronous Generator (ECSG) wind turbine. The most important aspects of the proposed ECSG wind turbine scheme are cost-effectiveness, simplicity and higher reliability, as well as higher efficiency. Considerable cost reduction for the converter unit of ECSG wind turbine is so important since costly converter has been one of the main challenges of the... 

Incoporating Gauge theory to study 4-dimensional manifolds,initiated by works of Donaldson,leading to resolve many problems of 4-dimensional topology.after Donaldson ,Seiberg and Witten introduced a novel Gauge theory that we will introduce and study some application of this theory.at beginning, we will establish Seiberg-Witten equation on these manifolds, following that we investigate moduli space of solutions of Seiberg Witten equations and later we define Seiberg - Witten invariants on these manifolds.at f we probe some applications of Seiberg-Witten invariants in Symplectic Geometry and we will show that Seiberg-Witten invariants are non-zero for Symplectic manifolds with canonical SpinC... 

The Z-source and quasi-Z source inverter have a capability to increase and decrease the output voltage without using extra switching stages or transformer. Therefor these inverters are an excellent choice for applications such as photovoltaic sources because of their higher efficiency, higher reliability and lower volume and cost. One drawback of these inverters is the leakage current that causes undesirable effect on the power system and safety issues. In this research we are going to develop a new modulation method for these inverters to reject the leakage current. In this method the harmonic content of common mode voltage is concentrated on the switching frequency and its harmonics while... 

Bhaskar, one of the pioneers of critical realism, pursues two aspects in his presentation in order to solve complex problems in the philosophy of science. The first aspect is highlighting and emphasizing the need of philosophy of science for ontology and paying attention to intransitive objects. The second aspect is acknowledging the social nature of science and the consideration of transitive objects of science as materials of knowledge, or in other words, the material causes of knowledge. What is done in this thesis, after a detailed description of Bhaskar's critical realism, is to examine the three categories of rationality, progress, and scientific realism in his view. With a layered... 

Scientific realism has always faced continuous criticism from anti-realists. Kyle Stanford's argument based on the problem of "unconceived alternatives" can be seen as a late and troublesome version of these challenges. In this thesis, first in the first chapter, after explaining the main points of conflict in the scientific realism/anti-realism debate, we will list the main positions in these two camps, and then we will mention the arguments in favor of scientific realism. After that, we will list the main challenges that scientific realism has faced. Arguments such as pessimistic meta-induction and underdetermination which are raised against scientific realism. In the second chapter, we... 

According to authorities and statistical figures, Iran is seriously facing insufficient housing crisis. Studies show that through an increase of 1.5 million units in annual housing construction capacity, this crisis will be overcome in 5 years. Although successful execution of such a big project is not unprecedented in the world, housing experts believe fulfillment of this plan through traditional method of construction in the country is impossible. The country's capacity of industrialized construction which is known as the remedy, is only limited to 2-3% of total construction. Thus development of this approach through financial, legal, ... supports of investment in prefabrication... 

Due to daily decrease of fossil energy resources, increase of environmental pollution which is included of toxic and greenhouse gases, and extensive growing rate of demands in transportation industry, especially vehicle industry, developing solutions in using fuel cells are vital for this industry in our country. Fuel cells are green, efficient and also powerful energy generators. According to potential advantages of fuel cells, structure, performance, benefits and also types of fuel cells are introduced as a desired energy resource. Indentifying existing choices of energy generators and ranking them using MCDM (Multi-Criteria Decision Making) technique was the first step to perform a...