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process-optimization
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Total 113 records
Study of Interaction Between Environmental and Design in Optimization of Chemical Processes
, M.Sc. Thesis Sharif University of Technology ; Bozorgmehri, Ramin (Supervisor)
Abstract
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...
Reliability modeling of dynamic thermal rating
, Article IEEE Transactions on Power Delivery ; Vol. 28, issue. 3 , 2013 , p. 1600-1609 ; ISSN: 8858977 ; Zareipour, H ; Fotuhi-Firuzabad, M ; Sharif University of Technology
Abstract
In this paper, a Markov model for reliability analysis of transmission lines equipped with a dynamic thermal rating (DTR) system is proposed. Moreover, a fuzzy procedure is proposed to determine an annual equivalent fuzzy DTR number to represent hourly variations of the line DTR. To implement the fuzzy annual DTR in composite system reliability analysis, an interactive method resolution technique for solving fuzzy optimization problems is developed. This method is chosen to address the fuzzy constraints associated with the lines equipped with the DTR system. Numerical results are presented using the 24-bus IEEE RTS, and demonstrate the validity of the proposed approaches
Reliability modeling of dynamic thermal rating
, Article IEEE Transactions on Power Delivery ; Volume 28, Issue 3 , 2013 , Pages 1600-1609 ; 08858977 (ISSN) ; Zareipour, H ; Fotuhi Firuzabad, M ; Sharif University of Technology
2013
Abstract
In this paper, a Markov model for reliability analysis of transmission lines equipped with a dynamic thermal rating (DTR) system is proposed. Moreover, a fuzzy procedure is proposed to determine an annual equivalent fuzzy DTR number to represent hourly variations of the line DTR. To implement the fuzzy annual DTR in composite system reliability analysis, an interactive method resolution technique for solving fuzzy optimization problems is developed. This method is chosen to address the fuzzy constraints associated with the lines equipped with the DTR system. Numerical results are presented using the 24-bus IEEE RTS, and demonstrate the validity of the proposed approaches
Divided POMDP method for complex menu problems in spoken dialogue systems
, Article 2010 IEEE Workshop on Spoken Language Technology, SLT 2010 - Proceedings, 12 December 2010 through 15 December 2010 ; 2010 , Pages 484-489 ; 9781424479030 (ISBN) ; Rahbar, S ; Sameti, H ; The Institute of Electrical and Electronics Engineers (IEEE); IEEE Signal Processing Society ; Sharif University of Technology
2010
Abstract
In this paper, a problem in spoken dialogue systems namely the menu problem, is introduced and solved by a POMDP model. To overcome the large size of the menu problem, a new method for achieving an optimal policy called divided POMDP method is introduced. Conditions for the problem to be solved by the proposed method are specified and the problem properties resulting in the given conditions are presented. The proposed method is evaluated using a typical menu problem with different menu sizes and it is shown that this method is superior to the conventional methods such as FRTDP for the problems it is capable to solve. Moreover, it converges faster in getting to an optimal policy
Enhancing bioleaching and iron oxidation efficiency of native strain of acidithiobacillus ferrooxidans, by optimizing the ambient growth conditions
, Article Pollution Research ; Volume 28, Issue 3 , 2009 , Pages 329-336 ; 02578050 (ISSN) ; Nemati, F ; Roostaazad, R ; Shitole, M. G ; Gade, W. N ; Sharif University of Technology
Abstract
In this study, we have investigated the bioleaching potential of a native strain of Acidithiobacillus ferrooxidans isolated from zinc and lead sulfide mines under varied ambient conditions of growth and substrate consumption. In the process of standardizing growth conditions to improve iron oxidation, bioleaching of zinc and lead is also found to be enhanced. The effects of pH, temperature, initial inoculum, Fe2+ and ammonium sulphate concentration on growth and bio-oxidation efficiency of the bacteria have been evaluated. The results indicate that the optimum pH required for the growth of the bacterium is 1.8; however, the same for maximum efficiency is 1.5. It is also found that pH has a...
Estimation of nitrogen content in cucumber plant (Cucumis sativus L.) leaves using hyperspectral imaging data with neural network and partial least squares regressions
, Article Chemometrics and Intelligent Laboratory Systems ; Volume 217 , 2021 ; 01697439 (ISSN) ; Pourdarbani, R ; Rohban, M. H ; García Mateos, G ; Arribas, J. I ; Sharif University of Technology
Elsevier B.V
2021
Abstract
In recent years, farmers have often mistakenly resorted to overuse of chemical fertilizers to increase crop yield. However, excessive consumption of fertilizers might lead to severe food poisoning. If nutritional deficiencies are detected early, it can help farmers to design better fertigation practices before the problem becomes unsolvable. The aim of this study is to predict the amount of nitrogen (N) content (mg l−1) in cucumber (Cucumis sativus L., var. Super Arshiya-F1) plant leaves using hyperspectral imaging (HSI) techniques and three different regression methods: a hybrid artificial neural networks-particle swarm optimization (ANN-PSO); partial least squares regression (PLSR); and...
Optimal production control and marketing plan in two-machine unreliable flexible manufacturing systems
, Article International Journal of Advanced Manufacturing Technology ; Vol. 73, issue. 1-4 , 2014 , pp. 487-496 ; ISSN: 02683768 ; Karimi, B ; Kianfar, F ; Sharif University of Technology
Abstract
In this paper, we have developed a production planning and marketing model in unreliable flexible manufacturing systems with inconstant demand rate that its rate depends on the level of advertisement on that product. The proposed model is more realistic and useful from a practical point of view. The flexible manufacturing system is composed of two machines that produce a single product. Markovian models frequently have been used in modeling a wide variety of real-world systems under uncertainties. Therefore, in this paper, the inventory balance equation is represented by a continuous-time model with Markov jump process to take into account machines breakdown. The objective is to minimize the...
Comparison of Dynamic and Static Performances of a Quaternary Distillation Sequence
, Ph.D. Dissertation Sharif University of Technology ; Shahrokhi, Mohammad (Supervisor) ; Bozorgmehri, Ramin (Supervisor)
Abstract
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...
Membrane Bioreactor for the Treatment of Dairy Industry Wastewater
, M.Sc. Thesis Sharif University of Technology ; Alemzadeh, Iran (Supervisor) ; Vossoughi, Manoochehr (Supervisor)
Abstract
The dairy industry wastewater has high biological oxygen demand(BOD) and high chemical oxygen demand(COD). In this study, membrane bioreactor(MBR) was used for the treatment dairy industry wastewater. Since two diffuser,submerged membrane modul and intermittent suction method were adpted to system. In this study, the response surface method and experimental design were applied as an alternative to conventional methods for the optimization of the treatment. A central composite design, with 5 replicates at the center point were used to build a model for predicting and optimizing the treatment. Mathematical model equations were derived by computer simulation programming with Design Expert...
, M.Sc. Thesis Sharif University of Technology ; Farhadi, Fathollah (Supervisor) ; Bozorgmehri, Ramin (Supervisor)
Abstract
In the present work, a comprehensive economic, environmental and exergy analysis and multi-objective optimization for world’s largest aromatic plant are provided and the interaction between decision variables in these criterions is discussed. In the first part, potentials of seven environmental features of the operational plant are quantified and normalized using life cycle assessment (LCA) for both process waste and utility environmental impacts. Exergy analysis (EA) is also used to determine the lowest eco-efficiency equipment. By choosing proper decision variables based on sensitivity analysis, LCA and EA results, optimization is performed to determine the best design variables based on...
Transplant Process Optimization in Kidney Donation Problem
, M.Sc. Thesis Sharif University of Technology ; Rafiee, Majid (Supervisor)
Abstract
At the present, End-stage renal disease(ESRD) is the ninth-leading cause of death in the USA.according methods of medical treatment for End-stage renal disease (ESRD), transplantation is the most viable renal replacement therapy for ESRD patients, there is a disparity between the demand for kidneys for transplantion and the supply. Incompatible inblood-type and antigen matching between patient-donor pairs is cause of shortage in disparity between the demand and the supply.paired kidney exchange of kidney among incompatible patient-donor pairs.PKE can be solve many difficulties in matching patient with incompatible donors. Kidney transplant surgeries in PKE must take place simultaneously...
Integrated and Multi-Scale Design of the Value Chain of Liquefied Natural Gas (Lng) Production from Associated Gas Considering Economic, Safety, and Environmental Objectives
,
Ph.D. Dissertation
Sharif University of Technology
;
Davood Rashtchian
(Supervisor)
;
Mahdi Sharifzadeh
(Co-Supervisor)
Abstract
Natural gas liquefaction is an enabling technology which could make natural gas resources globally accessible. Nonetheless, the design and operation of LNG processes is highly complex, and is subject to multiple criteria including energetic, environmental and safety performance. Moreover, such processes must be flexible enough to operate under different feed conditions. The present research applies integrated process and product design framework to enhance simultaneously energy efficiency, environmental benignness, and inherent safety of a small-scale LNG process. The challenge is that the current group contribution methods applied for the estimation of the thermophysical properties, suffer...
Design and Optimization of Helium Recovery Process from Natural Gas
, M.Sc. Thesis Sharif University of Technology ; Afshin, Hossein (Supervisor) ; Farhanieh, Bijan (Co-Supervisor)
Abstract
Helium is a valuable substance that is widely used in industry and medicine because of its unique properties. Due to the increasing demand for helium in the global market, several helium extraction units have been launched in the world in recent years; Nevertheless, there is still a significant gap between projected global helium production capacity and demand. Today, natural gas is known as the main source of helium on the earth. The method of industrial extraction of helium from natural gas is cryogenic. Due to the low temperature of this process, relatively high power consumption is used to extract helium from natural gas. Therefore, the optimization of this process is of great...
Development of Simulation Model and Optimal Design of Water and Energy Recirculation System in Residential Towers
, M.Sc. Thesis Sharif University of Technology ; Saboohi, Yadollah (Supervisor) ; Fathi, Amir Hossein (Supervisor)
Abstract
nowadays, due to population growth, unconventional use of water resources and on the other hand, climate change, limited renewable water resources, reduction of groundwater cavities, the need for water for agricultural use and energy production are increasing. Due to the fact that each cubic meter of dirty water pollutes 40 to 60 cubic meters of clean water and the entry of polluted effluent into the receiving sources of environmental degradation leads to a lot of wastewater treatment, water consumption management and The development of wastewater treatment processes is also becoming increasingly important. At present, wastewater treatment plants face the challenges of high energy...
Design and Optimization of Nitrogen Purification Unit based on Adsorption
, M.Sc. Thesis Sharif University of Technology ; Mousavi, Abbas (Supervisor) ; Fakhroleslam, Mohammad (Supervisor)
Abstract
In this project, in search of localization and synthesis of adsorbent for nitrogen purification in Pressure Swing Adsorption (PSA) units, studies have been carried out where after the finalized analysis around the choice of the adsorbent for synthesis and unit design, CMS has been choosen. Despite the lower selectivity compared to zeolite adsorbents in absorbing and separating oxygen from nitrogen, this adsorbent has been used as the first adsorbent in the industrial gas production industry due to higher nitrogen recovery and lower nitrogen absorption after economic studies in this field. In these days you can find few companies that use zeolite adsorbents to make nitrogen generators....
Optimal PV-FC hybrid system operation considering reliability
, Article International Journal of Electrical Power and Energy Systems ; Vol. 60, issue , September , 2014 , p. 325-333 ; Nowdeh, S. A ; Sharif University of Technology
Abstract
This paper presents an approach for optimal operation of a grid-connected hybrid system to maximize the system expected generated energy while maximizing the electricity sale revenue. The hybrid system consists of a photovoltaic (PV) module, an electrolyser (EL), hydrogen storage tank (HS) and a proton exchange membrane (PEM) fuel cell (FC). The generated energy is sold to the distribution grid. During the grid interruptions, the hybrid system output is used as an emergency supply to serve the local load, hence increasing the supply reliability. The proposed approach splits the whole problem in two sub problems: revenue maximizing problem (RMP) and expected generation maximizing problem...
Efficient stochastic algorithms for document clustering
, Article Information Sciences ; Volume 220 , 2013 , Pages 269-291 ; 00200255 (ISSN) ; Mahdavi, M ; Shamsfard, M ; Meybodi, M. R ; Sharif University of Technology
2013
Abstract
Clustering has become an increasingly important and highly complicated research area for targeting useful and relevant information in modern application domains such as the World Wide Web. Recent studies have shown that the most commonly used partitioning-based clustering algorithm, the K-means algorithm, is more suitable for large datasets. However, the K-means algorithm may generate a local optimal clustering. In this paper, we present novel document clustering algorithms based on the Harmony Search (HS) optimization method. By modeling clustering as an optimization problem, we first propose a pure HS based clustering algorithm that finds near-optimal clusters within a reasonable time....
Improved profitability of a pulping mill through progressive controller structure expansion
, Article Proceedings of the Institution of Mechanical Engineers. Part I: Journal of Systems and Control Engineering ; Volume 224, Issue 6 , 2010 , Pages 771-787 ; 09596518 (ISSN) ; Sharif University of Technology
Abstract
It has been well documented that multivariate systems will benefit from application of advanced control strategies. The application of these methods has thus far been hindered for a variety of reasons which range from complexity of the design methodologies to the cost associated with implementation of these solutions. This paper shows that there exist alternative means by which existing control strategies of a multivariate system could be extended, thereby leading to increased efficiency, without the need to remove and implement a new control system installation. A realistic model of an entire pulping mill is used in this paper to show that by careful selection of only a few additional...
Feeder growth: a new method for automatic optimal feeder design in gravity casting processes
, Article Structural and Multidisciplinary Optimization ; Volume 39, Issue 5 , 2009 , Pages 519-530 ; 1615147X (ISSN) ; Davami, P ; Sharif University of Technology
2009
Abstract
The optimal feeder design in gravity casting processes is considered. The design problem is formulated as an additive, growth-like, evolutionary topology optimization problem. The initial design of the presented method is a casting part which is placed in a suitable environmental mould box. The method is composed of three stages: determining the feeder-neck connection point on the casting surface, constructing the feeder-neck and the feeder growth. During the growth stage, the feeder topology is changed gradually until satisfying some predefined criteria. The design of multiple feeders is also considered in this work. In the presented method, feeders are designed in a descending order of...
An optimization method for radial forging process using ANN and taguchi method
, Article International Journal of Advanced Manufacturing Technology ; Volume 40, Issue 7-8 , 2009 , Pages 776-784 ; 02683768 (ISSN) ; Karimi Taheri, A ; Movahedi, M. R ; Sharif University of Technology
2009
Abstract
In this study, the artificial neural network (ANN) and the Taguchi method are employed to optimize the radial force and strain inhomogeneity in radial forging process. The finite element analysis of the process verified by the microhardness test (to confirm the predicted strain distribution) and the experimental forging load published by the previous researcher are used to predict the strain distribution in the final product and the radial force. At first, a combination of process parameters are selected by orthogonal array for numerical experimenting by Taguchi method and then simulated by FEM. Then the optimum conditions are predicted via the Taguchi method. After that, by using the FEM...