A Quasi-Three-Dimensional Multiscale Model for Two-Phase Simulation of Multi-Stream Plate-Fin Heat Exchangers

, Ph.D. Dissertation Sharif University of Technology Niroomand, Reza (Author) ; Saeedi, Mohammad Hassan (Supervisor) ; Kazemzadeh Hannani, Siamak (Co-Supervisor) ; Mafi, Mostafa (Co-Supervisor)

Abstract

The present thesis aimed to develop a thermal-hydraulic model for simulation of multi-stream plate-fin heat exchangers. In this study, a multi-scale point of view was employed for three-dimensional simulation of multi-stream plate-fin heat exchangers. This is a cost-effective method that reflects the effects of complex phenomena at the micro-scale in the macro-scale model. In this model, fluid and solid matrix temperature distributions were obtained in the three-dimensional space, considering conduction heat transfer through separating plates, side plates, cap plates, and transverse conduction through fins. The modular form of the model has facilitated layer-by-layer simulation of parallel...

Determine oil content in petroleum waxes

, Article Hydrocarbon Processing ; Volume 85, Issue 6 , 2006 , Pages 95-97 ; 00188190 (ISSN) Mafi, M ; Yazdani, F ; Farhadi, F ; Sharif University of Technology

2006

Test Case Selection in Test-Driven Development

, Ph.D. Dissertation Sharif University of Technology Mafi, Zohreh (Author) ; Mirian Hosseinabadi, Hassan (Supervisor)

Abstract

The large number of unit tests produced in the test-driven development (TDD) method and the iterative execution of these tests extend the regression test execution time in TDD. This study aims to reduce test execution time in TDD. We propose a TDD-based approach that creates traceable code elements and connects them to relevant test cases to support regression test selection during the TDD process. Our proposed hybrid technique combines text and syntax program differences to select related test cases using the nature of TDD. We use a change detection algorithm to detect program changes. Our experience is reported with a tool called RichTest, which implements this technique. To evaluate our...

Physical and hydraulic properties of a new spring packing

, Article CHISA 2006 - 17th International Congress of Chemical and Process Engineering, Prague, 27 August 2006 through 31 August 2006 ; 2006 ; 8086059456 (ISBN); 9788086059457 (ISBN) Mafi, M ; Yazdani, F ; Farhadi, F ; Deldari, H ; Sharif University of Technology

2006

Abstract

Physical and hydraulic properties of new stainless steel spring packing are introduced. The measured hydraulic properties are: dry and wetted packed bed pressure drop, loading and flooding points and the liquid holdups. The appropriate coefficients for predicting the mentioned hydraulic properties from different correlations are also reported. Hydraulic properties for this packing are compared with available packings. In spite of small size, the dry and wetted packed bed pressure drops of spring packing are less than similar Raschig and Protruded rings. The total liquid holdup of this packing is greater than other commercial packings. The big total liquid holdup and physical surface area are...

Process optimization and modeling of heavy metals extraction from a molybdenum rich spent catalyst by aspergillus niger using response surface methodology

, Article Journal of Industrial and Engineering Chemistry ; Volume 18, Issue 1 , January , 2012 , Pages 218-224 ; 1226086X (ISSN) Mafi Gholami, R ; Mousavi, S. M ; Borghei, S. M ; Sharif University of Technology

2012

Abstract

The present study examines the biorecovery of heavy metals from a spent refinery catalyst obtained from one of the oil refineries in Iran using Aspergillus niger. Bioleaching experiments were carried out in batch cultures using A. niger in the one-step process to mobilize Co, Mo and Ni from hazardous spent catalysts. Response surface methodology (RSM) was applied for the design and analysis of experiments with the optimization of pH, temperature, inoculum percentage, pulp density and rotation speed during the bioleaching of the metals. Experiments were designed as per the central composite design (CCD) technique. Three cubic mathematical models were derived for prediction of the responses....

Heavy metals recovery from spent catalyst using acidithiobacillus ferrooxidans and acidithiobacillus thiooxidans

, Article ICCCE 2010 - 2010 International Conference on Chemistry and Chemical Engineering, Proceedings, 1 August 2010 through 3 August 2010, Kyoto ; 2010 , Pages 331-335 ; 9781424477647 (ISBN) Mafi Gholami, R ; Borghei, S. M ; Mousavi, S. M ; Sharif University of Technology

2010

Abstract

In this investigation, a spent processing catalyst from one of the oil refineries in Iran was initially characterized physically and chemically. Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans were used to mobilize aluminum, cobalt, molybdenum and nickel from hazardous spent catalysts. Bioleaching experiments were performed in batch cultures. The growth characteristics of the bacteria (pH, Eh, cell concentration and ferrous and ferric iron concentration) were determined during bioleaching along with the concentration of metal values extracted from the catalyst. The results obtained from Inductive coupled plasma-optical emission spectrometry (ICP-OES) showed that after the...

Efficiency-effectiveness assessment of national innovation systems: comparative analysis

, Article Journal of Science and Technology Policy Management ; 2021 ; 20534620 (ISSN) Bakhtiar, A ; Ghazinoory, S. S ; Aslani, A ; Mafi, V ; Sharif University of Technology

Emerald Group Holdings Ltd 2021

Abstract

Purpose: The purpose of this paper is to present and evaluate the performance of innovation systems by considering two indicators of efficiency and effectiveness. The scope of the evaluation is globally and due to the situation of each country, the suggested strategies are proposed to maintain the status quo or move toward the desired situation for countries. Design/methodology/approach: The approach is to compare and benchmark the countries in terms of the efficiency and effectiveness of their innovation system. The Global Innovation Index report’s input-to-output ratio and the global competitiveness report are used for the assessment. Findings: The findings indicate that countries such as...

Efficiency-effectiveness assessment of national innovation systems: comparative analysis

, Article Journal of Science and Technology Policy Management ; Volume 13, Issue 3 , 2022 , Pages 625-651 ; 20534620 (ISSN) Bakhtiar, A ; Ghazinoory, S. S ; Aslani, A ; Mafi, V ; Sharif University of Technology

Emerald Group Holdings Ltd 2022

Abstract

Purpose: The purpose of this paper is to present and evaluate the performance of innovation systems by considering two indicators of efficiency and effectiveness. The scope of the evaluation is globally and due to the situation of each country, the suggested strategies are proposed to maintain the status quo or move toward the desired situation for countries. Design/methodology/approach: The approach is to compare and benchmark the countries in terms of the efficiency and effectiveness of their innovation system. The Global Innovation Index report’s input-to-output ratio and the global competitiveness report are used for the assessment. Findings: The findings indicate that countries such as...

Design and Simulation of CMOS Based Magnetic Sensor for Biosensing Applications

, M.Sc. Thesis Sharif University of Technology Mafi, Alireza (Author) ; Akbari, Mahmood (Supervisor) ; Fotowat-Ahmady, Ali (Supervisor)

Abstract

This paper presents a scalable and ultrasensitive magnetic biosensing scheme based on on-chip LC resonance frequency-shifting. The sensor transducer gain is demonstrated as being location-dependent on the sensing surface and proportional to the local polarization magnetic field strength |B|2 generated by the sensing inductor. To improve the gain uniformity, a periodic coil is proposed as a substitution for the standard process coil. As an implementation example, the circuit is designed in a 65nm CMOS process. The spatially uniform sensor gain of the array is verified by COMSOL simulations. Overall, the presented sensor demonstrates an improvement in the uniformity of the inductor’s magnetic...

Multi-variable Optimization of Vehicle Seat Suspension Considering Human Body Model Using Spring-Damper Isolators and Genetic Algorithm

, M.Sc. Thesis Sharif University of Technology Mafi Shourestani, Farid (Author) ; Moradi, Hamed (Supervisor) ; Vossoughi, Gholamreza (Supervisor)

Abstract

In recent years, the seat suspension system in commercial vehicles, industry, agriculture, transportation and … have been focused by researchers. Designing the spring-damper isolators for vehicle’s seat can be an achievable and suitable strategy to increase the comfort and decrease the risk of injuries in vehicles. In this research, the effect of vibrations due to road roughness has been examined by dynamic modeling of a vehicle in combination with the human body model. Thus by using spring-damper isolators and genetic algorithm, we try to optimize the performance of the system. Designing parameters includes the stiffness and viscosity of seat isolator and our target functions include the...

Study, Analysis & Optimizing The Process Of Approval, Design & Implementation Of Projects In The Iranian Oil Terminal Company(IOTC)

, M.Sc. Thesis Sharif University of Technology Moosavi, Saeed (Author) ; Mostafavi, Mostafa (Supervisor)

Abstract

Since the Iranian oil terminals company(I.O.T.C.) has been the main and strategic gateway of exporting petroleum in the country and plays an important role in the optimum continuity of national, regional and international energy supply chain and also conducting the needed projects whit a desirable quality and minimum time and cost has a prominent influence on steady continuity of manufacturing, importing and exporting of petroleum and gas production. The main purpose of doing this thesis is diagnosing the process of approval, design and implementation of projects in the I.O.T.C., Thus, whit regarding to the modern needs of implementing projects and the necessity of reviewing the structure...

Study & Analysis of Delays Causes of Gas Projects in Tehran Gas Company & presenting Optimized Solutions by Applying Project Management Principles

, M.Sc. Thesis Sharif University of Technology Ghiasi, Elahe (Author) ; Mostafavi, Mostafa (Supervisor)

Abstract

To deliver gas in time to different consumers like as industrial, commercial and domestic users is one of the most important parts in gas industry. So it is very important to utilize these projects in the specified time. There are huge harms for client, contractors and consumers when there is a delay in project utilization. To identify effective parameters on delays to remove them in future is an essential factor. In this research, all delay causes for TPGC (Tehran Province Gas Company) projects are analyzed and some solutions to remove these delays are presented. 10 hypotheses in relation of gas delivery have been assumed as delay causes. Then some questions have been discussed in relation...

Service Level Agreement Templates and Guides for Implementing, using eTOM

, M.Sc. Thesis Sharif University of Technology Mahdioun, Saeid (Author) ; Mostafavi, Mostafa (Supervisor)

Abstract

Nowadays, in communication industry, specially data network, in which service quality is a serious parameter, request for making connection with appropriate quality (Proportionate to demands) and necessity of clarification of obligations of service providers and customers, as well as customer awareness of submitted materials and offering various services with different qualities & costs, led service providers, specially IP based networks, to make agreements with their customers, entitled service Level Agreement (SLA). The SLA specifies the service type, mutual obligations, related parameters, measuring methods, violation threshold, penalties and loss compensation. Whereas, applying...

Condition Monitoring of Water Pipelines by Using Acoustic Method a Study of Leak Detection in ABFA

, M.Sc. Thesis Sharif University of Technology Alimoradi, Farid (Author) ; Mostafavi, Mostafa (Supervisor)

Abstract

Water is crucial to human being. We use water for a wide variety of uses daily. However, leakage has caused substantial water loss to our precious processed water. The major contributor to non-revenue water in Iran is pipeline leakages. The water industry in the nation has invested in equipment to detect and localize leaks in water distribution systems. One of the equipment mentioned is acoustic-based. The principle of acoustic is that whenever a leak is present in a pipeline, noise is generated and will travel along the pipeline. The acoustic leak detection method is then derived by calculating the distance traveled by this noise generated by the leak. Different equipment based on acoustic...

Assessment and Performance Improvement of Hierarchical Voltage Control System

, M.Sc. Thesis Sharif University of Technology Davoodi, Ehsan (Author) ; Parniani, Mostafa (Supervisor)

Abstract

Hierarchical voltage control is one of the conventional kinds of coordinated voltage control schemes which has been studied in some countries in the last decades. In this method network is divided into several voltage control regions and in each region voltage profile is controlled near optimal level, satisfying the economic and secure goals of the network performance. In this thesis, after the explanation of the main concepts of this scheme, its effects on the network voltage control is assessed and its performance is improved. First the primary concepts of hierarchical voltage control are explained. Then, the methods of the control regions determination and pilot nodes selection are...

Analyzing the Healthcare Wastes and Feasibility Study of Related Items (Plastics)

, M.Sc. Thesis Sharif University of Technology Mesbah, Niousha (Author) ; Mostafavi, Mostafa (Supervisor)

Abstract

Increasing population and competition for producing various productions and also more consumption in recent decades, result in producing more wastes. Therefore effective and continuous waste management is essential for monitoring the process (from the wastes generation source to the waste disposal) and establishing the efficient strategies to reduce wastes. One of the major sources of waste generation is hospitals that cause lots of environmental problem unless they are managed properly.Recycling is an important element of waste management that can reduce costs by innovative and proper management. The purpose of this research is identification of recyclable plastic items and estimates the...

The Analysis of Total Productive Maintenance Based on Computerized Maintenance Management System

, M.Sc. Thesis Sharif University of Technology Behshad, Amir (Author) ; mostafavi, mostafa (Supervisor)

Abstract

The main purpose of this thesis is to analyze the total productive maintenance based on computerized maintenance management system. At first, a detailed study on total productive maintenance is performed and then the requirements of this maintenance strategy are specified. Also, a computerized maintenance management system is defined which can help total productive maintenance to reach to its requirements. Finally, a conceptual model and entity-relationship model for computerized maintenance management system data base has been created

Study of HVDC Transmission for Offshore Wind Farms Based on Voltage Source Converters

, M.Sc. Thesis Sharif University of Technology Safaeian, Reza (Author) ; Parniani, Mostafa (Supervisor)

Abstract

In this thesis, DC transmission of offshore wind farms is studied thoroughly. Various system configurations that are introduced in the literatures are discussed and their control scheme for normal conditions and grid faults are studied. Then, the HVDC transmission based on voltage source converter, located between a local offshore ac grid and the onshore ac system is investigated as the most practical choice. The HVDC linke circuit elements are calculated and the control strategies of the offshore and onshore converters are introduced. DFIGs are considered to be the best choice for the offshore wind turbine generators. Then, the system is simulated and the frequency of the offshore grid is...

Feasibility Study of Manufacturing of Disposable Plant Containers

, M.Sc. Thesis Sharif University of Technology Ansari, Mahmood (Author) ; Mostafavi, Mostafa (Supervisor)

Abstract

Although laws vary in the competitive business world of today and the changing supply and demand parameters show that the process of delivering new products to market is very important.Most organizations today have found that spending more than ever on trusting in traditional competitive levers such as quality, cost reduction and differentiation in selling more products and services are not enough to be successful in market, instead notions such as speed, flexibility andagility can have a significant trend toward offering new products and services. There aresome good reasons for knew that organizations need new ways to develop their new products to survival, compete with its competitors and...

Modified Load Scheduling Using Smart Meters

, M.Sc. Thesis Sharif University of Technology Bahrami, Shahab (Author) ; Parniani, Mostafa (Supervisor)

Abstract

Implementation of various incentive-based demand response strategies has great potential to decrease peak load growth and customer electricity bill cost. Using advanced metering and automatic demand management makes it possible to optimize energy consumption, to reduce grid loss, and to release generation capacities for the sake of providing sustainable electricity supply, and reducing electricity bills for the customers. With these objectives, this thesis examines the previously suggested load scheduling programs in both residential and industrial sectors, and proposes new practical strategies for load management. This thesis has mainly focuses on three subdivisions of load management...