Sharif Digital Repository

Water is used as a key material in different processes of chemical industries. Considering abundant demand of chemical industries for water, pollution that threats this valuable material and the fact that there is currently no proper substitute for water, an urgent necessity is felt for economic utilization of water in industrial processes and optimal use of water resources. A variety of methods have been developed for analysis of water consumption in industrial processes, amongst are Pinch methodology and Mathematical Programming approach. In this thesis a Petroleum Refinery has been preferred as a case study in which optimization of water consumption in the aforementioned petroleum... 

Improvement of axial flow compressor is usually goal of manufacturers of these equipments. Because basic role of it in gas turbine efficiency too many researchers have effort to know phenomenon and effect of them on axial flow compressor's revenue and optimization of them. In this project the aerodynamic of axial flow compressor studied and effect of important parameters such as diffusion factor coefficient, optimum incidence angel and Mach and Reynolds number determined from text and papers. Then obtained a model from experimental data to determine shock loss and extended algorithms to specify critical Mach number and chocking mass flow. With quotation Craig and Cox method we determined a... 

In this project Visbreaker furnace was modeled and optimized. For this goal, Lobo & Evans method and refinery data was used. Effect of parameters such as, excess air, stack height, decoking period, burn out and fuel heat value were investigated. Among optimization method, genetic algorithm and MITA (Musical Instrument Tempering Algorithm) were used to minimizing cost function of furnace. Also based on Zone method, profiles of properties of process fluid were obtained. Finally fuzzy logic was used for furnace behavior identification  

The Curing of thick thermoset parts of composites Experience substantial temperature overshoot, especially at the center of those thick parts and large temperature gradient exists through the whole part due to large amount of released heat, thickness and low conductivity of the composite.this leads to non-uniformity of cure, residual stress and consequently composite cracks and possibly degradation of the polymer. In this thesis, first a thick cubic geometery of glass/epoxy composite is modeled with the help ofa commercial CFd packageand sensitivity to different effective parameters of this process is investigated with the help of this model.This model is then substituted by a trained... 

Popular usage of composite materials in aerospace, civil and defense industries in the last decades has been caused more attention to optimization of composite problems. Due to natural complexity of composite problems, i.e. discrete nature, complex dependence between design variables, existence of too much local optimum and etc., traditional methods of optimization are inefficient and it is necessary to use a powerful method to work cost effectively. Genetic algorithm as a technique through evolutionary algorithms is the most popular methods of tackling composite problems. The success of a genetic algorithm can be quantified by estimating the cost, time required and the quality of final... 

Management decisions, Enhanced Oil Recovery, and reservoir development plans in petroleum industries are based on predictions by reservoir simulation. Due to uncertainties in model parameters or engineering assumptions, the simulation results are not accurate, while they are correct. One remedy is to match simulation results with engineering measurements, typically pressure and flow rate, by adjusting model parameters. In Reservoir Engineering literature, this is called History Matching and is an optimization problem. Common methods of history matching are based on finite difference simulation, and therefore have a very low speed. In addition, these methods usually ignore Geostatistical... 

Adjoint-based aerodynamic optimization has drawn much attention, recently. It is based on gradient optimization procedures and requires the sensitivities of the design variables to find the optimized shape. The advantage of this method is that it estimates the sensitivities by solving an “adjoint equation”, instead of calculating them directly. In this thesis, the method is used to design airfoil shapes both in inviscid and viscous flows. In this regard, a flow solver and an adjoint solver have been developed. First, the validity of the flow solver is tested according to credited data form papers and softwares. Then, the optimizing program is tested using some inverse design problems.... 

Cylinders are one of the most applicable components in industry. According to the application of these elements, reinforcement and stiffening are the common ways to enhance mechanical properties of them. Nowadays, by advent of new materials such as functionally graded materials (FGMs), a novel method of improving these structures is discovered. By application of FGMs, many physical and mechanical characteristics of these structures can be modified. In this thesis, vibration analysis and frequency optimization of a stiffened cylinder made from FGMs are performed. FGM which is employed in this investigation is made from two different materials, to have better modal properties which cause in... 

By applying the Pinch Technology and Exergoeconomic simultaneously, to a complex process system, beneficial and energy-efficient measures are identified.In the present research “Three-link-model” Exergoeconomic methodology optimizes the system and contrary to traditional exergoeconomic methods, reversed method is used. The approach proposed for optimization of such a complex system is to iteratively optimize subsystems. Since assumptions considered by conventional Exergoeconomic for calculating the cost-optimal exergetic efficiency and relative cost difference, are not applicable, new assumptions are to be considered. Unlike traditional Exergoeconomic method, product’s exergetic specific... 

The enzyme L-Asparaginase (L-asparagine amidohydrolase, EC 3.5.1.1) has been thoroughly researched by many researchers worldwide because of its immensely useful medical applications. It can catalyze the hydrolysis of L-asparagine to L-aspartic acid and ammonia that is effective for the cure of leukemia, especially for puerile Acute Lymphocytic Leukemia [ALL] and Lymphosarcomas. The present study discusses the studies carried out for the optimal production of the enzyme from Escherichia coli ATCC 11303. For extraction of the intracellular enzyme, Sonication is more useful method for cell disruption than alkali lysis and enzymatic method. We improved Luria Bertani (LB) media (tryptone 1% w/v,... 

Optimization always has been a major industrial field of study. Optimization is the process of finding the best result based on some events. In design, construction and maintenance of any kind of engineering system ,engineers must take a lot of decisions in the case of management or engineering at different levels in order to minimize the attempts to reach the optimum conditions and obtain the maximum profit on the other side. high speed of processing and litle time for calculations by using computers is very common nowadays which is caused in many improvements in optimization approaches. In this thesis some different classical optimization methods have been applied on Williams-Otto reactor... 

Purpose of ongoing thesis is providing a tool for suitable modeling, increase efficiency and decrease construction cost of solar absorption heat pump. At first, the solar absorption heat pump is modeled by the thermodynamic laws. Then, this model is converted to the new standard mathematical programming model using exergy and thermodynamic Analysis with considering all technical and economic constrains. This mathematical model is optimized by Genetic algorithm (GA). Because of the nonlinear objective function and the constraint, GA is used as optimization algorithm. After applying GA, optimized parameters of cycle heat exchanger designing and its electricity consumption are calculated.... 

Micro combined heat and power (MCHP) system is one of the most worldwide considered energy saving with high total efficiency systems. This research presents the application of MCHP to small scale users such as residential or light commercial buildings. Initially, the available technology in micro scale that can be used as an energy generator has been specified and categorized. Since then, by using the overall energy purchased cost by households assuming the energy carriers are kerosene, gas and electricity, total demand has been determined considering that the electricity expenses showing the use of electric appliances and the gas expenses expressing the cost of domestic hot water and... 

Xylitol is a sugar alcohol or polyol that has been used as a food additive and sweetening agent due to Its high sweetening power, anti-cariogenic properties and possibilities for use in diabetic food products, makes xylitol an attractive sucrose substitute in a wide variety of foods and beverages. Xylitol is a five carbon polyol or pentitol obtained by the hydrogenation of xylose. xylitol could be produced from xylose in rice seed coats medium by Saccharomyces cerevisiae. For xylitol production, S.cerevisiae was grown in preculture medium at 30°C and agitated at 120 rpm on a rotary platform shaker. The cells were harvested after 20hr, were centrifuged and transferred to the production... 

Biodiesel as an alternative fuel for fossil diesel has many benefits such as reducing regulated air pollutants emissions, reducing greenhouse gases emissions, being renewable, biodegradable and non-toxic. In this study, used frying oil was used as a low cost feedstock for biodiesel production by alkali-catalyzed transesterification. The used frying oil was originally a mixture of various oils obtained from vegetables that are native to Iran. The design of experiments was performed using a 5-level-5-factor central composite design coupled with response surface methodology in order to study the effect of factors on the yield of biodiesel and optimizing the reaction conditions. The factors... 

The Revenue management concept has been studied and noticed by researchers for more than forty years. Although the applications of revenue management grow in different industries continuously, airline industry which is the origin of this research area is the pioneer of developing and representing new models. In the last few years, there has been a trend to enrich traditional revenue management models. In this thesis we first, reviewed most aspects of revenue management studies especially in airline industry, then choice-based customer behavior concept is introduced. Also a case sample study in customer choice behavior has been developed with time scale considering and remodeled. According to... 

Asphaltene precipitation and deposition may cause severe problems during different stages of oil recovery. All proposed remediation techniques have proven costly and not highly effective, so prevention becomes the most beneficial way to counteract the problem. Revelation of the deposition mechanism and determination of the parameters are necessary in order to devise reliable prevention strategies.This work presents results of the effect of lean gas and CO2 injection process as well as natural depletion on dynamic asphaltene precipitation and deposition. In addition sets of experiments were performed in the same porous media using STO and solvent (with different volume ratios) to investigate... 

The actual flow stream through compressor is 3D and fluctuated because of complicated geometry, fluid viscosity and high velocity. Therefore, more accurate analysis of this kind of flow, it is better to use 3D model. Nowadays the flow modeling software are able to model and analysis flow regime using numerical methods in three dimensions. Using these software allow us to find the ways which can reduce the energy losses to improve compressor efficiency.In current work, based on 3D numerical analysis, the flow regime in a centrifugal compressor is investigated and also the sensitivity of this analysis with mesh sizing is explored. The k-e type RNG model is used for modeling turbulent behavior... 

This paper presents a surface generation model for sculptured surface productions using the ball end milling process. Dimensional measurement using a coordinate measuring machine (CMM) has been commonly adapted in advanced manufacturing environment to ensure that manufacturing products have high quality and reliability. To conduct dimensional inspection efficiency in a computer integrated manufacturing (CIM) environment, there is an urgent need to derive a sampling strategy which can be used to specify a set of measuring points that lead to accurate sampling while minimizing the sampling time and cost. Owing to the variations in characteristics of geometric feature and manufacturing process,... 

Poly (Lacticacid) belongs to the family of aliphatic polyesters. PLA can be made from annually renewable resources to yield articles for use in either the industrial packaging field or the biocompatible /bioabsorbable medical device market. Production of PLA through polycondensation in an industrial way was the aim of this project. In order to have the appropriate reaction conditions a steel reactor was designed and constructed. Feasibilty of PLA production in the constructed reactor was investigated and the product was analyzed, using H-NMR and FT-IR spectrum analysis. The average molecular weight was measured by GPC and ubbelohde viscometery method. Studies have shown that oligomerization...