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shahbazi--h
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Combustible organic materials : determination and prediction of combustion properties
, Book
De Gruyter
2018
Argumentation theory : a pragma-dialectical perspective
, Book
Springer International Publishing AG
2018
Effect of Temperature Gradient on Ultrasonic Flowmeters
, M.Sc. Thesis Sharif University of Technology ; Sadrhosseini, H (Supervisor) ; Kazemzadeh Hannani, Siamak (Co-Advisor)
Abstract
Ultrasonic flowmeters are one of the common and profitable measurement tools and applied in many industrial fields.Ultrasonic flowmeters work based on transit-time technique. The transit-time utilizes the propagation time of the ultrasonic signal in the fluid. Since ultrasonic signals can also penetrate solid materials, a pair of transducers is installed on the surface of tube. Each transducer works alternatively as both transmitter and receiver of ultrasonic signals.In this study, effect of temperature gradient on flowmeter measurements by applying constant temperature and uniform heat flux on the boundary is investigated numerically for methane gas in laminar flow regime and the results...
Effect of Carrier Gas Pressure on the Size of Cu Nanoparticles Prepared by ELM Method
, M.Sc. Thesis Sharif University of Technology ; Halali, Mohammad (Supervisor)
Abstract
In this report the important factors affecting the levitation melting of copper are discussed. Pure copper nanoparticles were synthesized by utilizing an Electromagnetic Levitation Melting Gas Condensation (ELM-GC) method. Pure bulk copper samples were melted and evaporated by electromagnetic levitation technique in an inert gas atmosphere in a silica tube. Copper nanoparticles were formed from ascending vapor by employing high purity argon and helium as carrier gases and cooling agents. The pressure of inert gas was changed in both helium and argon atmospheres to investigate on pressure’s effect. Particle size and morphology of the produced nanoparticles were studied by Field Emission...
Assessing and Comparing Risk indices in BOT and DBB Delivery Methods in Freeway and Highway Construction Projects
, M.Sc. Thesis Sharif University of Technology ; Khaloo, Alireza (Supervisor)
Abstract
The present survey study aims at investigating and comparing risk indices in highway and freeway projects implemented through Build-Operate-Transfer (BOT) and Design-Bid-Build (DBB) delivery methods. In this regard, two distinct questionnaires were developed (one for BOT and one for DBB delivery method) and interviews were conducted, too. The questionnaires were, then, sent to the target population, i.e. all the experts and agents involved in highway and freeway construction projects implemented through either BOT or DBB method. The collected data were then submitted to Statistical Package for Social Sciences (SPSS), version 22.00, to be analyzed. The results showed that risks had generally...
Developing a New Method to Estimate Taxing Electricity Sector Carbon Emissions based on Social Cost of Carbon Emissions
, M.Sc. Thesis Sharif University of Technology ; Avami, Akram (Supervisor) ; Moeini Aghtaei, Moein (Co-Supervisor)
Abstract
Controlling, managing, and mitigating the emission of greenhouse gases, especially carbon dioxide, which are produced by human activities, are one of the main concerns of researchers today. Market-based methods are one the successful methods to enhance controlling, managing, and mitigating carbon dioxide emissions, among which the carbon tax has received more attention. Increasing clean technologies in the electricity network to the reduce the emissions of the electricity industry may reduce the carbon tax rate. In this regard, the life cycle analysis makes it possible to consider the emissions of the life cycle. The present model is applied for two representative days of Iran's electricity...
Efficient Multimedia Transmission over Wireless Sensor Networks
, M.Sc. Thesis Sharif University of Technology ; Movaghar Rahimabadi, Ali (Supervisor)
Abstract
One of the basic characteristics of Wireless Sensor Networks is their resource limitations. As a result, it is essential to try to decrease costs in such networks. These limitations are more critical in transmitting multimedia data with larger data units. In addition, when transmitting real-time multimedia data, delay is an important factor to consider. According to these limitations, Wireless Multimedia Sensor Networks are congestion prone. In this thesis, a transport layer protocol has been proposed. This protocol consists of three three steps in handling congestion. First, it detects congestion according to the queue length in the node. If the lsength is greater than a minimum threshold,...
Light Duty Vehicles' Emission Reduction Potentials in Megacities
Using New Powertrain Technologies (Case Study: Tehran)
,
M.Sc. Thesis
Sharif University of Technology
;
Erhami, M. (Mohammad)
(Supervisor)
;
Pourzahedi, H. (Hossein)
(Supervisor)
Abstract
Tehran is one of the most polluted megacities in the world, and based on different studies, vehicular sources are responsible for most of the criteria pollutant emissions in this city. The number of vehicles on the streets has been increased drastically leading to growing amount of emission and this trend is continuing. In order to reduce the amount of vehicular emission, it is vital to investigate the factors affecting vehicles emission in this city. This could help to find efficient solutions to improve the situation. Hence, a low-cost methodology to estimate the vehicular emissions is developed. In this...
Adjoint Inverse Modeling of PM2.5 Emissions in Order to Improve Performance of Air Quality Models
, Ph.D. Dissertation Sharif University of Technology ; Hosseini, Vahid (Supervisor) ; Mozafari, Ali Asghar (Supervisor)
Abstract
In atmospheric studies, chemical transport models are formulated to simulate the spatial and temporal distribution of pollutant concentrations. However, the performance of these models is strongly dependent on the input parameters such as emissions. Inverse modeling is a widely used mathematical approach for estimating model parameters by minimizing the discrepancy between model output and observations. For air quality studies, inverse modeling is often used for emission inversion as emissions are associated with significant amount of uncertainties.This research aims to estimate optimal values for anthropogenic PM2.5 emission through a four-dimensional variational (4D-Var) inverse modeling...
Condition Monitoring of CNG Electrocompressors
, M.Sc. Thesis Sharif University of Technology ; Behzad, Mahdi (Supervisor)
Abstract
In order to increase the service life and prevent the breakdown of apparatuses, instalations and equipments, we are in a position to maintain them. In this regard, there are three methods for maintenance of machineries, which are called reaction maintenance, preventive maintenance and predictive maintenance. By carrying out a predictive method or monitoring the situation, it is possible to know the health of the machine and take the necessary measures before the damages occurs. Vibration analysis, temperature analysis, oil analysis and flow analysis can be used for monitoring the situation. Reciprocating compressors are one of the most costly repair equipment that needs to be monitored...
Investigation the Effects of Inversion on Tehran Air Quality Using Meteorological and Photochemical Models during Normal and High Concentrations Episodes
, M.Sc. Thesis Sharif University of Technology ; Hosseini, Vahid (Supervisor) ; Rashidi, Yousef (Co-Advisor)
Abstract
In this study, The Comprehensive Air Quality Model with extensions (CAMx model, v5.41), was used to model gas phase pollutants over Tehran modeling domain during two episodes of July 7th to July 13th and November 30th to December 6th, 2012. In the second episode due to very high concentration of pollutants caused by a combination of meteorological conditions and occurrence of an inversion, a forced holiday was imposed on the city-wide operations to protect the health of citizens. It was found that WRF/CAMx modeling system is a useful tool for the analysis of urban environmental problems and predicting critical conditions. The WRF simulation results for 2-m height temperature, 10-m height...
Fabrication and Electrical Properties Evaluation of PA/CNT Conductive Nanocomposite with Low Percolation Threshold
, M.Sc. Thesis Sharif University of Technology ; Bagheri, Reza (Supervisor)
Abstract
Polyamide-6 is a thermoplastic polymer that is classified as electrically non-conductive materials. One way of adding conductivity to the polymer matrices is by utilizing them in a nanocomposite form. Superior mechanical and electrical properties of Carbon Nanotubes make them worthy of being chosen as reinforcement in nanocomposites to extend their operation to a broader range of applications, like conductive nanocomposites, mainly polymer-based matrices. The Nanotubes have chemical affinity and tend to entangle and aggregate. Because of this, to achieve a uniform and remarkable electrical conductivity is hard-to-reach. state of entanglement effects correctly melt methods of polymer blend...
HDR Image Reconstruction from a Single-Exposure LDR Image
, M.Sc. Thesis Sharif University of Technology ; Amini, Arash (Supervisor) ; Mohammadzadeh, Nargesolhoda (Co-Supervisor)
Abstract
High dynamic range (HDR) images provide more realistic experience in displaying real-world scenes than conventional low dynamic range (LDR) images by providing much more detailed luminance information; However, most imaging content is still available in low dynamic range. Inverse tonemapping is known as the problem of inferring an HDR image from a single-exposure LDR image in which the lost data caused by saturation of bright parts and quantization must be reconstructed.To address this problem, in this thesis, two fully-automatic architectures based on convolutional neural networks, are proposed. Both these architectures utilize a number of convolutional auto-encoders as...
Fully Digital Implementation and Optimization of Openhole Oil Well Surface Modem
, M.Sc. Thesis Sharif University of Technology ; Movahedian, Hamid (Supervisor) ; Gholampour, Iman (Co-Supervisor)
Abstract
Once a well has been drilled before it is cased with the steels (open-hole well), some logging must be done to record information’s about layers, geologic formations, geophysical and petrophysical properties of well. All the information’s that gathered from sensors and tools transmitted to the surface by a down-hole modem. This information is corrupted during the transmission by the communication channel. The most notable influence of this channel is noise, attenuation and interference between successive data bits. On the other hand, the characteristic of channel changes with the length of the cable, temperature, connections and so on. So using a set of fixed filters is not effective. The...
Fault Tolerant AC/DC/AC Converters for Wind Energy Turbine with Doubly-Fed Induction Generator
, Ph.D. Dissertation Sharif University of Technology ; Zolghadri, Mohammad Reza (Supervisor) ; Saadate, Shahrokh (Supervisor)
Abstract
AC/DC/AC converters are widely being used in a variety of power applications. Continuity of service of these systems, as well as their reliability and performance are now of the major concerns. Indeed, the failure of the converter can lead to the total or partial loss of the control of the phase currents and can cause serious system malfunction or even shutdown. Thus, uncompensated faults can quickly endanger the system. Therefore, to prevent the spread of the fault to the other system components and to ensure continuity of service, fault tolerant converter topologies associated with quick and effective fault detection and compensation methods must be implemented. In this thesis, the...
Simultaneous Hypothesis Testing and False Discovery Rate
, M.Sc. Thesis Sharif University of Technology ; Alishahi, Kasra (Supervisor)
Abstract
The purpose of this thesis is to introduce and review a recent methods in simultaneous hypothesis testing. False discovery rates, Benjamini and Hochberg’s FDR Control Algorithm, is the great success story of the new methodology. Much of what follows is an attempt to explain that success in empirical Bayes terms.The later chapters are at pains to show the limitations of current largescale statistical practice: Which cases should be combined in a single analysis? How do we account for notions of relevance between cases? What is the correct null hypothesis? How do we handle correlations? Some helpful theory is provided in answer, but much of the argumentation is by example, with graphs and...
Design Hybrid Renewable Energy Systems by A Multi-objective Robust Optimization Model
, M.Sc. Thesis Sharif University of Technology ; Eshghi, Kourosh (Supervisor)
Abstract
Nowadays the popularity of renewable energy is increasing due to its clean and inexhaustible nature. Also, if the local potential of each area is used, there is no cost to connect to electricity network. But these energies have low reliability due to their oscillating nature. To solve this problem, it is proposed to use systems based on several sources of energy called hybrid systems. In this research, a mathematical model is proposed to design a renewable hybrid system that minimizes the present value of costs while maximizing system’s reliability. To consider the uncertainty in the solar radiation data and energy demand, Bertsimas’s robust model is applied to our model. In which variables...
Second-order calibration for simultaneous determination of pharmaceuticals in water samples by solid-phase extraction and fast high-performance liquid chromatography with diode array detector
, Article Chemometrics and Intelligent Laboratory Systems ; Vol. 137, issue , 2014 , pp. 146-154 ; ISSN: 01697439 ; Parastar, H ; Sharif University of Technology
2014
Abstract
A fast high-performance liquid chromatography-diode array detection (HPLC-DAD) approach combined to solid phase extraction (SPE) as a pre-concentration step is developed for simultaneous determination of five selected pharmaceuticals (carbamazepine, naproxen, diclofenac, gemfibrozil and mefenamic acid) in water samples. The effective factors on the efficiency of SPE procedure are optimized using faced-centered central composite design (FCCD). In addition, multi-response optimization by using Derringer's desirability function is used to find the optimum experimental conditions for extraction of analytes from well and river waters. Due to the complexity of water matrices and the presence of...
Solving the minimum toll revenue problem in real transportation networks
, Article Optimization Letters ; 2014 ; ISSN: 18624472 ; Aashtiani, H. Z ; Sharif University of Technology
2014
Abstract
As a means to relieve traffic congestion, toll pricing has recently received significant attention by transportation planners. Inappropriate use of transportation networks is one of the major causes of network congestion. Toll pricing is a method of traffic management in which traffic flow is guided to proper time and path in order to reduce the total delay in the network. This article investigates a method for solving the minimum toll revenue problem in real and large-scale transportation networks. The objective of this problem is to find link tolls that simultaneously cause users to efficiently use the transportation network and to minimize the total toll revenues to be collected. Although...
Novel unbreakable solid-phase microextraction fibers on stainless steel wire and application for the determination of oxadiargyl in environmental and agricultural samples in combination with gas chromatography-mass spectrometry
, Article Talanta ; Vol. 128, issue , 2014 , Pages 231-236 ; ISSN: 00399140 ; Baghernejad, M ; Bagheri, H ; Sharif University of Technology
2014
Abstract
Sol-gel based solid-phase microextraction fibers supported by a stainless steel wire were fabricated and employed for GC-MS determination of oxadiargyl in real samples. The fibers were based on four compounds with different polarity: polar and non-polar (end-capped) poly(dimethylsiloxane) (PDMS), polyethylene glycol (PEG), and poly(ethylene-propyleneglycol)-monobutyl ether (UCON). For this purpose, the surface of the stainless steel was initially modified by (3-mercaptopropyl) trimethoxysilane. The results of the modification procedure were evaluated by cyclic voltammetry and energy dispersive X-ray (EDX) spectroscopy. After the modification, four different sol-gel based SPME fibers with...