Sharif Digital Repository

Since steady state behavior of a plant is affected by the change of various inputs to the plant, the transient behavior of the chemical plants are also very important in their general performance. On the other hand, catalytic hydrotreating is one of the most important processes in crude oil refining process in many aspects such as economical, technical and environmental. Thus, the goal of this project was dynamic simulation and control of catalytic hydrotreating unit (UNIFINER Unit) of Tehran Refinery with using the HYSYS software. To fulfill this target, data that were necessary for simulation were gathered from Unifiner unit of Tehran refinery at first. Then, steady state simulation of the... 

Many processes in the real world are multiple-input multiple-output (MIMO) systems. There are often some interactions between the inputs and outputs. In the other words, every input affects on several outputs, and every output is affected by several inputs. In order to control of these systems, we usually desire to decouple the loops into multiple non-interacting SISO systems after proper pairing of manipulated and controlled variables. Loop interactions can destabilize a control system, so tuning controllers in an interacting MIMO system can be difficult. Decoupling problem has been discussed in the two domains: linear control and nonlinear control. However, both of them need an exact model... 

Industrial water systems often allow efficient water uses via water reuse and/or recirculation. The design of the network layout connecting water-using processes is a complex problem which involves several criteria to optimize. The general problem can be formulated as a non-convex nonlinear program (NLP), but due to the presence of bilinear terms, it may be difficult for local optimization solvers to attain global optimal solutions. To overcome this difficulty, this paper presents a hybrid approach combining the global optimization power of evolutionary algorithms and speed and accuracy of mathematical programming technics.By this strategy, local solutions can be avoided and the... 

Inherent safety means that the process is naturally safe and the conditions of occurrence of unsafe cases and situations are eliminated from the system so that unsafe conditions can be controlled and prevented from occurrence by means of layers of protection. In general, evaluation of inherent safety may be studied in two different conditions; the first one is associated with the units that are not completely designed and built yet. In the initial steps of developing a process, there is much freedom in the determination of materials, equipment, and designing variables. As soon as the process enters its life cycle, making changes in the process will be very difficult and expensive. Therefore,... 

In this work steady state and dynamic performances of quaternary distillation column sequences designed based on steady state and dynamic cost functions have been investigated. To quantify the dynamic performance, product loss due to disturbances has been considered in the objective function. In addition, variations of operating costs such as utilities have been considered in the objective function. To separate a quaternary mixture into four products, twenty two configurations have been used. It has been observed that the feed composition, disturbance frequency and magnitude affect the dynamic behavior strongly. To decrease the optimization computational load, a scheme that provides a... 

Reduced-order modeling (ROM) is a novel approach in all realms of computational science including reservoir simulation. Among various ROM methods, Trajectory Piecewise Linearization (TPWL) is on its evolution for reservoir applications. Previous investigations reflect promising future for incorporating TPWL into the next generations of enhanced reservoir simulators. In this work, we employ TPWL to investigate the claimed efficiency, robustness and accuracy of this method as a surrogate simulator for a developed reservoir simulator. The self construction of the used simulator gives us the opportunity to explore this method and to examine previous assertions on the subject. The efficiency of... 

Traditionally, chemical Process design is focused on the selection of technologies and optimization based on economic consideration .In the 1970’s because of the global energy crisis, other consideration consider with economic goals .in this study we are eager to provide design procedures and guidance for optimizing chemical processes simultaneously based on economic and environmental aspects .this optimization is applied to production maleic anhydride(MA) from n-butane feedstock .an optimization algorithm based on the genetic algorithm with four decision variables(recycle flow ratio ,air to feed ratio ,solvent flow and reactor temperature ).for including dynamic objective in optimization... 

In this study, a tree-dimensional random pore-scale network model is used to simulate the membrane contactor porous medium. Drainage and imbibition phenomena is simulated to have a better knowledge of liquid and/gas intrusion trough the membrane porous structure. A genetic algorithm is used as an optimization tool. Several variables such as the number, radius and location of pores, the coordination number, as well as the radius and length of the throats are used herein as the optimization parameters. The difference between the binary SEM images and virtual sections on the generated network in conjunction with the permeability and mean pore size data were selected as the objective function.... 

All living entities requires energy to continue their lives. In human beings this energy is provide through consumption of food, at first the consumed food gets converted to glucose and the produced glucose enters the blood and then goes to the body cells in which it is used to produce the required energy. The essential hormone which makes it possible to use Glucose for energy production is INSULIN. In the patients suffering from Type 1 Diabetes, lack of Insulin production makes it impossible for the cells to use Glucose for the production of their required energy. In these patients due to the fact that the blood Glucose is not used by the cells, the Blood Glucose Level (BGL) increases,... 

Application of the advanced control techniques and information technology in the biomedical engineering have been the focal point of the research communities in biomedical engineering due to the rapid growth of the nonlinear control theories along with the computer hardware. In this work the application of differential geometry and globally linearizing control has been applied to efficiently control the first phase of HIV disease based on the HIV infection model proposed in the literature. All the efforts have been in the way to obtain a suitable scenario of drug administration to suppress and control the infection. In the proposed scenario, drug administration is time dependant and... 

In this project a framework for Model Based Fault Diagnosis (MBFD) in a Gas Transmission Network (GTN) was developed. A black-box linear state-space model was used to capture dynamic behavior of an industrial benchmark for GTN. A full fledge commercial network simulator were used to obtain the required data for process identification. In order to check the robustness of the model zero mean white noise was imposed on various output obtained by the commercial simulator. Kalman filter was used to estimate the states of the GTN. These estimated states along with the measured output (all obtained from the commercial simulator) are almost similar to their corresponding estimated signal. This shows... 

Compact linear accelerator is equipped with a single fixed motorized wedge that produces different wedge angles by combining an open and a wedged field in the appropriate proportions.
In this work, the required data for the Treatment Planning System, TPS were generated for utilizing Compact motorized wedge, MW and was verified by dosimetry. To verify MW, the accumulated wedge profiles at a depth of 10 cm for different wedge angles were measured using 2-D Profiler and were calculated the wedge angles using an analytical formula. The validity of effective wedge angles 2-D Profiler has been done by determining the wedge angles in accordance with ICRU-24 for compact MW and Telecobalt... 

Nowadays diabetes is considered as one of the common diseases among mankind. Different body organs utilize the glucose or the sugar existed in various kinds of food as an energy source in order to provide required energy for their activities. Insulin hormone which is created by the pancreas gland has a very significant role in easing the respective procedure. Therefore, when the body is not capable of producing enough insulin, then glucose aggregation in the blood leads to higher blood sugar and thus a disease called diabetes type1. Up to now, considerable research activities have been done regarding the diabetes type1modelling. One of the bolded drawbacks of such models is that the effect... 

Supply Chain is a complex system and its modeling generally results in complicated mathematical problems. Solving these problems, one should make assumptions that make solutions impractical. Knowledge-based frameworks such as ontology has been proposed for tackling this issue. In this thesis, with relying on a seven step ontology developing method, UML as development language and Rational Rose as development software environment, an application ontology for supply chain and its problems has been developed. Furthermore, with use of a Benzene, Toluene and Xylene supply chain as an instance, it has been shown qualitatively how to use the ontology in various supply chain problems. It is... 

Due to continuous improvements in manufacturing and the fact that modern technologies such as microprocessors, are becoming more efficient along the rapid growth of nonlinear control methods usage, the application of these two tools together has entered various fields of biomedical engineering, particularly neural prostheses. In this study, the methods of analysis and control of nonlinear systems were used to investigate and improve the behavior of the neural breathing system on the basis of Hodkgin-Huxley model as the original model of the neuron. Using the principles of differential geometry and robust control methods – based on combination of exact input-output linearization ideas,... 

Finding the optimal heat integrated distillation column sequence is an utmost important optimization problem in process engineering. The frequently used approach in this area is to obtain a suitable sequencing candidate and then accomplish the heat integration based on the application of Pinch technology to finalize the design. This approach reduces the problem complexity at the expense of not necessarily reaching the best possible result. This work follows a genetic super structure approach to systematic and rigorous synthesis of optimal multi-component distillation sequences (including simple and thermally coupled complex columns) and simultaneously heat exchanger networks by using a... 

The main objective of the present work is to achieve green design of a methanol plant by using life cycle process design (LCPD) and multi-objective optimization. As a starting point, simulation of Lurgi’s combined reforming process as a conventional reference methanol case (RMC) was performed in order to obtain its operational and kinetic parameters as well as its environmental impacts. The environmental concerns were calculated using one of the modern environmental impact assessment methods, i.e. life cycle assessment (LCA). To perform life cycle assessment of RMC, methanol production plant as well as its auxiliary units should be considered. The auxiliary units in the RMC include cryogenic... 

Development of pore network models for real porous media requires a detailed understanding of physical processes occurring on the microscopic scale and a complete description of porous media morphology. In this study, the microstructure of porous media has been represented by three dimensional networks of interconnected pores and throats which are designed by an object oriented approach. Afterwards, the connectivity of the system has been optimized by an optimization algorithm. To validate the methodology, a network of a carbonate sample is constructed. In this model, the geometrical characteristics of the pores and throats, such as their shapes, effective radii and lengths, are selected... 

Diabetes has become the most prevalent disease all among the world. One of the complications of this disease is diabetic nephropathy. Diabetic nephropathy occurs when the kidney cells encounter high glucose concentration for long periods. Kidney cells use glucose as their energy supply. However, the excess glucose in the diabetics triggers specific gene pathways, gradually leading to diabetic nephropathy. As a result, proteins’ levels and the activity of transcription factors change during the disease progression. Diabetic nephropathy is characterized by excessive deposition of the proteins comprising the extracellular matrix in the mesangium, basement membrane of the glomerulus, and in the... 

In this thesis, the latest human respiratory system is extended such that it addresses the effect of blood acidity on the performance of the human respiratory system. Since the model does not take into account any controller, two PI controllers proposed by Bental have been used to simulate the closed loop behavior of the respiratory system. Since, in the original model blood pH is considered as a constant value, the extended model has been used for the case where the blood pH pumped by heart is assumed to be and the obtained results have been compared with those of the original model. The similarity of the results shows the extended model to be valid for the normal case. Model since t he...