Sharif Digital Repository

The industrial paradigm shift toward intelligent and sustainable management stimulates policymakers to leverage artificial intelligence for the decentralized planning of chemical industries with energy networks. By doing so, this work firstly presents a simulation framework to investigate the rigorous transient behavior of integrated systems comprising natural gas and power transmission networks, along with a chemical plant whose feedstock is natural gas. This framework entails dynamic models for the gas transmission network and the SynGas plant, and a continuous-time AC-power flow formulation with dispatchable loads. It addresses the following key challenges: (i) analyzing energy and... 

Information and Communication Technology and Artificial Intelligence (AI) can support the transition from traditional practices toward smart supply chain coordination schemes. Such a direction allows for integrating organizational levels of natural gas transportation enterprises, comprising Location, Inventory, and Routing Problem (LIRP) decisions. Specific works have investigated the LIRP of natural gas-to-product and energy networks. However, due to the absence of a systematic ICT-assisted mindset, no study has been oriented from the perspective of the dynamic inventory management and geographic data-driven features of land resources. To handle these challenges, this study partially... 

Dynamic modeling and process control, especially the equipment of bioreactors and fermenters, have always faced many challenges due to the complexity and high uncertainty of the kinetics of environmental reactions. Among these, semi-continuous fermentation for bioethanol production is one of the important technologies in biochemical industries. The problem of modeling as well as controlling the use of the main discontinuous and semi-continuous methods of ethanol production is the lack of uniform state conditions and the possibility of aerobic and non-aerobic multiplication conditions in two ways. The main goal of this research is to obtain a new method in modeling bioethanol fermentation and... 

For the simulation of microbial systems, constraint-based models have been proposed. The most famous constraint-based model is the flux balance analysis, in which to apply extra-molecular effects into the system, the dynamism of the problem is also introduced to generate the dynamic flux balance analysis. In this thesis, the bee colony optimization algorithm is used as an optimization engine. To increase the simulation accuracy and obtain more accurate solutions, this method was further developed and tested with thirteen benchmark functions. Better results were obtained compared to other proposed algorithms. Then the proposed algorithm was developed with four methods for constrained... 

Flash calculations using equations of state are the basis of compositional simulators and inaccuracy in these calculations leads to errors in some time steps or even complete failure of a simulation. One of the problems of this approach is the use of iterative loops, which leads to a high computational cost. The purpose of this research is to use deep machine learning methods, namely multi-layer perceptrons and convolutional neural networks to solve this problem. At first, we defined two 5-component and 10-component hydrocarbon fluid models and used one of the conventional methods of flash calculations (Modified Successive Substitution method) in order to generate the data required for... 

Model Predictive Controllers are one of the most powerful control strategies. This type of controller operates on the basis of optimizing an objective function. In some control problems, model predictive controllers cannot be used due to the high number of optimization variables and high sampling rate. In order to be able to use this type of controllers in these systems, solutions have been proposed, one of which is to perform the optimization using analog computation. In this thesis, it is assumed that the optimization problem is linear or quadratic programming, and for each of these optimization problems, analog architectures are presented that perform the optimization based on analog... 

The Oil wells are usually damaged because of the drilling process and production scenarios or fluid injection during EOR processes. These damages would critically affect the rate of production and injectivity of the well in the form of plugging damage. Different methods are used to fix these damages and increase the production flow from the oil wells. One of the most widely used well-stimulation methods to remediate this challenge is well acidizing. Although this method has very high efficiency in improving the ability of wells, if it is not designed and implemented correctly and optimally, it can cause induced damage and even lead to the well shutting. This challenge is especially reported... 

With the daily increasing demand for energy, we are facing many crises, such as environmental pollution and global warming, etc. Geopolitical issues can also lead to problems for some countries in reaching the energy demand considered in their development plan of them. For this purpose, a part of the global research is focused on removing these obstacles. One of the methods that can be used to produce cleaner fuel, or more precisely "biofuel", is the gaseous fermentation of synthesis gas by microorganisms and algae. A rod-shaped, anaerobic microorganism called Clostridium ljungdahlii uses synthesis gas for its reproduction. In other words, this bacterium can ferment carbon monoxide, carbon... 

Dynamic modeling and control of bioprocesses, especially bioreactor and fermenter equipment, has always faced many challenges due to their complexity and high uncertainty. One scientific approach to modelling of such complex systems is the use of neural networks. Recently, an approach called hybrid networks has become popular, whose structure incorporates some of the basic rules, such as the mass balance of reactive species. Practically, it can also be used as a ‘software sensor’ or non-measurable state estimator. In this project, a bread yeast production bioreactor is used as a reference process and a hybrid neural network is used to estimate unknown parameters of biochemical reactions. In... 

Statistics show that cancer is the second leading cause of death in the world. In recent years, several studies have shown that combination therapy is more effective than single therapy. Modeling and simulation the dynamics of cancer and the immune system and controlling the dose of cancer drugs complement preclinical trials. The aim of this study was to apply the model predictive control approach to determine the optimal dose of chemotherapy and immunotherapy drugs to treat cancerous tumors. Thus, with a preliminary analysis of the analytics, a six-state dynamic model has been selected as a hypothetical patient to advance therapeutic goals. Two sets of parameters for the hypothetical... 

Upstream oil industry operators have turned to optimal production methods for further recoveries, such as smart wells. Control algorithms for smart wells must be equipped with online measurements, in other words, reflected in the feedback philosophy. On the other hand, after discretization, an oil reservoir's dynamic and control-driven model becomes a realization or a large-scale and sparse state space. One way to deal with this problem and provide an appropriate model for the design of smart well controllers is to use appropriate reservoir dimensional reduction methods. Therefore, to design low-order controllers, a study must first be performed at the level of the reservoir model and its... 

To ensure stable and optimal operation of lithium-ion batteries (LIBs), it is necessary to use a management system for online monitoring and accurate estimation of battery State of Charge (SOC). Due to LIBs' complex dynamics and effective factors such as temperature and side reactions, battery SOC estimation has become one of the greatest challenges for experts in the field. In this research, an adaptive sliding mode observer has been designed and evaluated for a cylindrical lithium manganese oxide battery with a capacity of 1258 mAh. At first, rigorous simulation of lithium-ion battery has been performed by utilizing the P2D electrochemical as well as thermal and aging model to be the main... 

Microbial desalination cells have been considered as one of the most promising technologies in water desalination and wastewater treatment. Due to slow biological processes, experimental approach toward these types of cells has always been a challenge. Consequently, modeling and simulation techniques are crucial to be developed in order to avoid wasting time and resources.In this study, a dynamic model for a microbial desalination cell consisting of three parts: anode, cathode and desalination section is proposed in which changes in microorganism concentration, acetate concentration as anode feed, oxygen concentration in cathode, pH changes and electrical potential drop in anode and cathode... 

Carbonate Matrix acidizing in order to improve or increase initial permeability, leads to different dissolution patterns under different operating and environmental conditions. In a specific rock / reactive fluid system, when a reactive fluid injects into the system in an optimal velocity, the dissolution pattern proceeds like a finger, names Wormhole. Formation of Wormhole is known as a success in acidizing process, because of its optimum porosity and permeability evolution and minimum pore volume injected of reactive fluid to breakthrough. So prediction of optimum injection velocity and analysis of dissolution patterns variation by change in operational and environmental conditions,... 

Conventional methods of solving partial differential equations such as finite difference method, finite volume method, and finite element method require mesh generation in the problem domain. When these methods are applied to solve problems involving shock propagation, crack propagation or deformable domain, or in the case of mesh refinement, multiple mesh regenerations are needed which is laborious and time consuming. In recent years, meshless methods have been developed to avoid difficulties of mesh-based methods. Meshless Local Petrov-Galerkin (MLPG) method is a truly meshless method that does not rely on mesh neither in function approximation nor in the integration of the weak form. In... 

Continued uncontrolled gas emission can cause extreme changes in climate all over the world and threaten the life So, the removal and/or reduction of CO2 from the atmosphere is essential to prevent its side effects. CO2 separation is the costliest part of the gas removal process from fossil fuel combustion. Among several available CO2 capture technologies, the MEA-based post-combustion CO2 capture process is considered a mature technology for mitigating CO2 emissions. In this study a steady-state MEA-based CO2 capture process from the coal power plant is developed in Aspen Plus. Subsequently, steady-state model with appropriate modifications, is exported into Aspen Plus Dynamics to study... 

Today, shipping of liquefied natural gas has a considerable share in the global gas trade. Efficient design, optimal operation, and precise control of process variables in the gas liquefaction process decrease energy consumption for LNG production. Understanding the dynamic behavior of a liquefied natural gas unit helps engineers to make the correct choice of controlled variables and tuning controllers. Through a dynamic simulation, this understanding can be achieved. Simulation of a multi-stream heat exchanger, as the heart of the gas liquefaction process, is a challenge of studying this process. In this study, two dynamic models governing a multi-stream heat exchanger in Aspen Plus... 

The purpose of this project is to use adaptive model predictive and fuzzy controllers to control the pH in a proper location and right amount as well as applying optimal dose of electrical current to prevent the destruction of healthy tissue during treatment. Comsol software has been used to simulate the electrochemical treatment of liver cancer. Since the Comsol software does not have the ability to solve the tumor model in spherical coordinates, the modeling/simulation was performed in cylindrical ordinates. In this study, only the reactions of oxygen and chlorine production in the anode were considered. The predictive control used in this study is GPC type and fmincon algorithm is used... 

In this project, a viscous instability phenomenon in CO2 injection process has been investigated. The viscosity of CO2 is much less than the reservoir fluid and the resultant mobility ratio results in the instability of sweeping front. The instability may occur in a typical permeable thief zone. This is due to severe change in gas saturation and/or relative permeability of the gas, hence reducing the sweeping efficiency. This process severely affects areal recovery and results in the inefficacy or failure of gas injection process. Here we tried to simulate the phenomena by higher order finite element methods and the results are in agreement with the geometry of thief zone. Indeed, lower... 

Determining the parameters of the porous media and fractures in order to properly understand the processes governing these environments is very important. Traditionally, these parameters are determined in the laboratory. In recent years, with the advancement of computational capabilities, numerical methods have been considered to determine the parameters of the porous media. In the last few decades, the lattice Boltzmann method has been considered by the researchers as a class of computational fluid dynamic methods for simulating fluid flow. The advantages of the lattice Boltzmann method include simplicity in applying to complex media and the ability to simulate different phenomena. In this...