Sharif Digital Repository

Increased exploitation of energy resources has led to growing attention to the CHP systems due to their high efficiency. High energy loss in power transmission network, which is about 20 %, is an additional reason for growing attention to CHP. In addition to that, utilization of small scale CHP systems has provided ground for growing competition with distributed generators based on renewable energy resources. Selection of optimal technology based on economical and environmental criteria requires application of analytical tool. An analytical tool could avail itself of identifying optimal program for operation of cogeneration systems. The present research work has been implemented to develop... 

Analysis of energy flow which effectively leads to reducing energy consumption in buildings is of major importance. The following research is the development of methodology and simulation of energy in the residential buildings and realization of the methods by means of FORTRAN software. In the process of modeling energy flow, in order to evaluate thermal comfort and calculate building’s thermal load, the dynamic and integrated interaction of these parameters must be appraised. The continuous and integrated study required that Mass and energy flow, for various component of building, and their interaction be examined. These factors could not be assessed using simple and reliable methods. In... 

Modeling and Control are fundamental issues for fish robots, which can play basic roles in design, optimization, fabrication, and eventually utilization of them. A review on the literature reveals the shortage of an analytical closed form model with little simplifications and high precision, and also control works based on such models. Studying LAEBT theory, it is shown that this theory is suitable for determining the forces produced due to the tail movements considered in the present work, and then it is used to determine the forces. Experimental investigations by means of the setup made for this purpose showed that the obtained equations for the forces have got acceptable precision.... 

In this study, density, viscosity and surface tension of aqueous solution of Sulfolane, ( TEA+TMS+H2O) and (DIPA+TMS+H2O) systems were measured . Density, viscosity and surface tension were measured using pycnometer, Cannon – Fenske viscometer and Capillary rise method, respectively. Surface tension measurements of (DIPA+TMS+water) were carried out by the ring method using a LAUDR TD3 tensiometer,. The experiments were carried out in low concentrations and atmospheric pressure in the temperature range (70 - 30) . The obtained Data was modeled using empirical and thermodynamic models. Density calculation was done using the Setchenov and Redlich – Kister models.and the results indicated that... 

Nickel oxide is used in the manufacture of ceramic, magnetic materials, battery cathodes, electrochromic films, heterogeneous catalytic materials and gas sensors. NiO nano-powder can be produced with many different methods. The synthesis of NiO nanopowder has been carried out via solochemical processing from an aqueous solution of a Ni containing complex in this research. Another name for this method is two-stage solochemical (TSSC) method. This is the newest economic method for synthesis of NiO nanopowder. NiCl2 anhydrous and NH3-H2O used as the raw materials and H2O used as solvent. The results obtained from XRD and TEM show that the nanoparticles have cubic crystal structure and the mean... 

Hydrocracking is one of the most versatile petroleum refining process for production of valuable products including gasoline, gas oil, and kerosene. Various kinetic models have been proposed for hydrocracking process. A commonly used approach is to consider the mixture in terms of selected lums, which can be specified in terms of structural characteristics, such as boiling point. From this approach the reaction mixture can be considered in two types of discrete lumping and continuous lumping. In this thesis, a 5 parameter continuous kinetic lumping model was studied for modeling of the Isomax reactor of Tabriz refinery whose feedstock is a low quality gasoil from vaccum distillatin column.... 

Al-Mg alloys are used in many industrial fields, thus improvement of their mechanical properties is so important. Expressing mathematical models on the basis of physical and microstructural properties can be useful for this purpose. In this research, in order to study the microstructural evolutions and mechanical properties of the material, a dislocation based model and microstructural parameters such as grains and subgrains during plastic deformation and subsequent annealing are considered. In addition, a modification is used to make the model capable of justify the solute atom and temperature effect simultaneously. This makes the results to be more precise and accurate considering... 

P/E ratio is studied in four levels in this study:
1)Macroeconomics level
2)Capital market level
3)Industry level
4)Company level
The first level studies effects of macroeconomics variables on P/E ratio. At this level we use variables such as economic growth, inflation, exchange rate, and etc.The next level uses capital market variables such as market volume, and IPO information.The third level that we study in this research is industry level. Stocks of an industry generally behave similar, because they have common advantages and disadvantages, thus industry is an effective factor on P/E ratio.The last level studies financial statements and internal features of a... 

In this research, trade and transportation trends of Asia-Europe-Africa, in the both intercontinental and intracontinental levels have been analyzed. With analyses which are done in this research, determinant factors for modeling and investigating international bilateral trade in these three continents have been recognized. The relevant time-series data were extracted from centralized and international databases. The examined database consists of 11 variables grouped in four categories: bilateral trade data, transportation, geographical and socio-economic characteristics. Transportation data is based on three different networks. The first network consisted of highway, rail and marine modes... 

An event must be modeled in a way that either reflects a comprehensive perspective for the event or acts in an especial part of that event, roperly. The main aim of this thesis is to control. Therefore the models will be accepted whenever the suggested mathematical models can move towards controller final target, desirably.This thesis proposes a linear mathematical model, five nonlinear models and a simple model based upon Convolution, Fuzzy Regression and Neural Networks techniques for Acquired Immune Deficiency Syndrome (AIDS), respectively. The proposed models were achieved through studying 300 HIV+ Patients who were under Highly Active Antiretroviral Therapy (HAART) approach in Iranian... 

Nowadays, urban storm water management and wastewater reuse are of main concerns of urban managers. Changes in surface specifications such as imperviousness, manning coefficient, pollutant buildup … during catchment transformation of land use from natural to urban can lead to undesirable change in quality and quantity of catchment's outlet runoff that could cause serious damage to receiving bodies. In recent decades, urban designing's approach has been using detention and quality improvement systems in order to manage urban runoff. Urban runoff and its treatment system (BMP: best management practices) and urban lake (as a receiving body) have been modeled in this research. Velenjak stream's... 

Mass transfer laws and Microorganisms growth relations are the two important factor s in modeling the “anaerobic baffeled reactors ”.
In this peaper , behavior of the anaerobic baffeled reactors studyed with using mass transfer and mass balance equations, differential equations for the unsteady state condition have been produced , then , the best microorganism growth mechanism (Monod & Haldan) has been chosen using microorganism growth equations for anaerobic system and complete model equations for steady state and unsteady state conditions have been presented. Factors and constants of the model equation have been calculated by ... 

According to the unique characteristics and increased competition in Business-to-Business (B2B) exchanges, achieving customer loyalty is becoming more and more crucial in B2B marketing. Furthermore, with the advent of relationship marketing, it is important to sustain a long term relationship with customers.Thus, the major issue is to examine what influences a customer’s willingness to remain with the existing supplier. The purpose of this study is to identify the antecedents of customer loyalty in a Business-to-Business context. Based on the relevant literature on customer loyalty and satisfaction, a conceptual model is developed to assess the most influential drivers of loyalty. The... 

Ground water is one of major resources of drinking water in Iran and thus, its quality (in terms of absence of pollutants) is a matter of great importance. The main goal of this research was to investigate the pollution concentration in the Ground water and soil in the fields near South Pars Gas Complex Co. (SPGC). The second goal was to determined the source and measure the distribution of the pollutants (in case of presence) and determine potential risks caused by them. The first step was to perform experimental tests in the two regions. In SPGC region, a number of wells were chosen for sampling according to the direction of Ground water movement. All samples were taken using two EPA... 

Selection of muscle activation pattern to reach a specific goal by considering the complexities of neuromuscular system and the way it overcomes these complications, are of researchers’ space interest in motor control. One proposed solution for resolving these complexities is the concept of simple module (synergies) that suggests the combination of them leads to more complex activities. In the present work, the existence and arrangement of synergies in the lumbar spine have been studied. For this purpose, a model with 18- muscles at level of L4-L5 under utilized in the static condition. In order to obtain the muscular and stability synergies, a biomechanical model predicting muscle... 

Design and modeling of a micromechanism for generating planar, nano-scaled locomotion is the subject of this thesis. First, we introduced the concepts and fundamental definitions used throughout the thesis. Then, based on the classification of the locomotion principles employed in microrobots, the related literature about design and fabrication of different microrobots is investigated. Inertial slip generation and contact force variation, as the preferred group, is utilized for further analysis. Since friction force is the main propelling source in the microrobot’s locomotion principle, different models proposed for this phenomenon are investigated and the Coulomb friction model is selected... 

This PhD dissertation presents the chemometric techniques as a tool to obtain maximum information from the chemical and biological systems. In this regards, two objectives have been followed. The first objective was to apply the design of experiment methods for approaching the most reliable data. In this section, the main concepts and applications of experimental design approaches to optimize the common analytical chemistry techniques are reviewed. The critical steps and tools for screening including Plackett-Burman, full factorial- and fractional factorial designs and response surface methodology such as central composite, Box-Behnken and Doehlert designs are discussed. Descriptions of... 

Oil and gas upstream, is one of the major parts of the energy chain in the world. Processes of production, transportation, processing and conversion of energy carriers are the main parts of this sector. Process units of oil and gas upstream industry are some of most local and global pollution resources in the world. In this research, the consideration of the pollutions from the production, processing and conversion of fossil fuels sector and the optimization of the management choices of each pollutant is subjected. Consideration of the pollutants related to the upstream sector, pollution control and management choices, cost accounting of the environmental impacts, the methods of accounting... 

Mold/metal interfacial heat transfer coefficient (IHTC) is the most important parameter that influences the solidification and the mechanical properties of a solidified product. The present work focuses on the determination and evaluation of pressure effect on interfacial heat transfer coefficient from the experimental cooling curves during unidirectional solidification of A356 alloy against water cooled Gray iron mold (chill). For this purpose, inverse heat conduction method is used. The results showed that IHTC is not constant, but varies with time, temperature and pressure during solidification. IHTC variation is related to coherency and critical solid fraction during... 

During the brewing process, beer alternately goes through different chemical and biochemical reactions and solid–liquid separation stages. The clarification at the final step of brewing is a highly critical stage when it comes to producing a clear and bright beer. Recently, membrane technology has been successfully used in beer clarification, wherein Kieselguhr (diatomaceous earth) filtration is replaced by cross-flow microfiltration. The most important disadvantages of using microfiltration in clarification of beer is the fouling and flux decline during the process. The phenomenology of fouling mechanisms is still undefined and selection of an appropriate technique for flux enhancement in...