On competence of vendor managed inventory in supply chains using basic mathematical inventory models

, Article Scientia Iranica ; Vol. 21, issue. 3 , 2014 , p. 1061-1071 Jasemi, M ; Haji, A ; Gharibi, M ; Sharif University of Technology

2014

Abstract

In this study, a two-echelon single-vendor supply chain is selected to do a cost-based comparison between short-term performances of a Vendor Managed Inventory (VMI) and a Retailer Managed Inventory (RMI). While the inventory costs include ordering and storing expenses, the rate of consumption and the price of goods are constant, the rate of production and pace of transportation are infinite and shortage is not allowed. This paper, after a comprehensive literature review, is followed by three cases of single retailer, n-retailer and two-retailer chains. Unlike the second case, in the first case, VMI shows an absolute superiority to RMI, and this is the reason for devising the third case in...

A Polypropylene-Based Microextraction Method Coupled with HPLC-FD for Determination of Fluoxetine in Human

, M.Sc. Thesis Sharif University of Technology Gharibi Marzankola, Mahsa (Author) ; Bagheri, Habib (Supervisor)

Abstract

Considering principles of both micro-solid phase extraction (µ-SPE) and stir-bar sorptive extraction (SBSE) techniques, in this study a microextraction technique was developed using a polypropylene sheet as extracting device for isolation of fluoxetine from biological samples. Being rather inexpensive and simple to prepare extracting device, elimination of time consuming sorbent synthesis step and memory effect are some of the advantages of the proposed method. The extraction process was performed using a polypropylene sheet as extracting device. Solvent desorption was performed in a microvial and then extractant was injected into HPLC system. The effect of various parameters including pH,...

Investigation of carbon monoxide tolerance of platinum nanoparticles in the presence of optimum ratio of doped polyaniline with para toluene sulfonic acid and their utilization in a real passive direct methanol fuel cell

, Article Electrochimica Acta ; Volume 97 , 2013 , Pages 216-225 ; 00134686 (ISSN) Gharibi, H ; Amani, M ; Pahlavanzadeh, H ; Kazemeini, M ; Sharif University of Technology

2013

Abstract

Polyaniline fiber (PANI) was synthesized by chemical interfacial method and doped with para toluene sulfonic acid (PTSA) through a sequential doping-dedoping-redoping process resulting in PANI-PTSA. The doped material was utilized to fabricate Vulcan-polyaniline composite of C-PANI-PTSA. Next, through reduction, Pt particles were deposited on to this composite to produce a Pt/C-PANI-PTSA electrocatalyst. To investigate the PANI-PTSA interaction with the carbon support as well as, to consider its effect upon the catalytic activity of Pt/C-PANI-PTSA, electrocatalysts with different ratios of 10, 15, 20, 25 and 30 wt% were synthesized and their activity was compared with the Pt/C (Electrochem)....

Fabrication of MEA based on sulfonic acid functionalized carbon supported platinum nanoparticles for oxygen reduction reaction in PEMFCs

, Article RSC Advances ; 2015 , Pages 85775-85784 ; 20462069 (ISSN) Gharibi, H ; Yasi, F ; Kazemeini, M ; Heydari, A ; Golmohammadi, F ; Sharif University of Technology

Royal Society of Chemistry 2015

Abstract

The Nafion ionomer affects the efficiency of the platinum (Pt) catalyst by blocking the active sites thereby restricting the gas permeability of the catalyst layer; but, there is a limitation in the quantity of Nafion ionomer that needs to be added without affecting the cell performance. Sulfonation of carbon-supported catalysts as mixed electronic and protonic conductors has been reported to be an efficient way to increase the triple-phase boundaries. In order to improve the utilization and activity of cathodic catalysts in the oxygen reduction reaction (ORR), Pt nanoparticles were loaded on a mixture of Vulcan XC-72R and MWCNTs, which were functionalized in a mixture of 96% sulfuric acid...

Evaluation of Base Calling Methods in Next Generation Sequencing

, M.Sc. Thesis Sharif University of Technology Gharibi, Hadi (Author) ; Hossein Khalaj, Babak (Supervisor) ; Motahhari, Abolfazl (Supervisor)

Abstract

In the mid twentieth century by discovering the existence of genetic strands and understanding their role in diseases and phenotypes of species, research initiated to decipher their content. Sequencing of the first human genome at early twenty-first century paved the way to study and even cure complex human deseases having genetic origin. Next Generation Sequencing (NGS) Technologies have significantly reduced the expenses and the timing complexity of DNA Sequencing and this has an improving trend. In this thesis, we evaluate Base Calling methods, a critical step in analyzing next generation sequencing information and deals with massive sequencing data. Base Calling tries to optimally detect...

Influences of Magnetic Nanoparticles and Magnetic Field on the Performance of the Redox Flow Batteries

, M.Sc. Thesis Sharif University of Technology Rahimi, Mohammad (Author) ; Molaei Dehkordi, Asghar (Supervisor) ; Gharibi, Hossein (Supervisor)

Abstract

The novel concept of using magnetic nanofluidic electrolyte for redox flow batteries (RFBs) is demonstrated for the first time. In this regard, the stable magnetic nanofluidic electrolytes are prepared by dispersing magnetic modified multiwalled carbon nanotubes (MMWCNTs) in the positive electrolyte of a polysulfide-iodide redox flow battery at mass concentrations of less than 0.3 g L−1. The electrochemical behavior of magnetic nanofluidic electrolyte was examined using cyclic voltammetry at different mass concentrations of MMWCNTs with a carbon felt electrode. Higher and stable peak current densities were observed at larger mass concentrations of MMWCNTs. A polysulfide-iodide redox flow...

Novel magnetic flowable electrode for redox flow batteries: A polysulfide/iodide case study

, Article Industrial and Engineering Chemistry Research ; Volume 60, Issue 2 , 2021 , Pages 824-841 ; 08885885 (ISSN) Rahimi, M ; Molaei Dehkordi, A ; Gharibi, H ; Roberts, E. P. L ; Sharif University of Technology

American Chemical Society 2021

Abstract

A novel approach named a magnetic flowable electrode (MFE) is proposed for the first time to enable enhancement of redox flow batteries (RFBs) performance. This approach enables the formation of a high active surface area electrode from magnetic nanomaterials, without the need to fabricate a self-supporting three-dimensional electrode structure. To form a simple MFE, magnetic modified carbon nanotubes are dispersed in the electrolyte, and permanent magnets are embedded behind the current feeder to apply a magnetic field across the flow cell channels. With circulating electrolyte, magnetic carbon nanotubes are aggregated on the graphite bipolar plate to form a well-structured nanoscale...

Advances in heuristic signal processing and applications

, Book ; Chatterjee, Amitava ; Nobahari, Hadi ; Siarry, Patrick

Springer 2013

Abstract

There have been significant developments in the design and application of algorithms for both one-dimensional signal processing and multidimensional signal processing, namely image and video processing, with the recent focus changing from a step-by-step procedure of designing the algorithm first and following up with in-depth analysis and performance improvement to instead applying heuristic-based methods to solve signal-processing problems. In this book the contributing authors demonstrate both general-purpose algorithms and those aimed at solving specialized application problems, with a special emphasis on heuristic iterative optimization methods employing modern evolutionary and swarm...

Development of an Evolutionary Algorithm Based on Surrogate Models to be used in Multi-disciplinary Design Optimization of a Flying Vehicle

, M.Sc. Thesis Sharif University of Technology Ghoreishi, Mohaddeseh (Author) ; Nobahari, Hadi (Supervisor)

Abstract

In this research, multi-disciplinary design optimization (MDO) of a flying vehicle has been done based on the flight simulation. A meta-heuristic algorithm called Multi-objective Adaptive Real-coded Memetic Algorithm (MARCOMA) has been used for optimization. Since solving a MDO problem is a time consuming process, a RBF neural network has been used in the optimization algorithm as a surrogate model. The new algorithm, called MARCOMA+NN, has been tested with some standard benchmarks. MDO problem has six disciplines consists structure, aerodynamic, propulsion, guidance, control, and fire control. The MDO problem has 31 design variables and two objective functions. The objective functions are...

Optimal Design and Real-time Implementation of a Cooperative Guidance Algorithm against a Flying Vehicle

, M.Sc. Thesis Sharif University of Technology Motie, Mahyar (Author) ; Nobahari, Hadi (Supervisor)

Abstract

A cooperative aerial system to defense a Ground Station (GS), against an Incoming aerial Targets (IT) is presented. GS is surrounded by given terrains and a group of homogenous Unmanned Aerial Vehicles (UAVs) are employed using a novel online guidance algorithm in a decentralized manner. The proposed algorithm includes loiter, midcourse and terminal phases. During loiter; UAVs follow an optimal circular path. IT is supposed to approach GS along an optimal low altitude trajectory with respect to the terrains. UAVs are informed the initial position and velocity of IT and they are unaware of IT trajectory. Each UAV decides on whether to engage with IT or not, and shares its decision with other...

Synthesis and Characterization of PVDF Magnetic Nanocomposite

, M.Sc. Thesis Sharif University of Technology Hadi, Mina (Author) ; Forounchi, Massoud (Supervisor)

Abstract

PVDF (polyvinylidene fluoride) magnetic nanocomposite films were prepared by solution casting using two types of nanomagnetic particles: (i) magnetic nanoparticles synthesized by using an alkaline solution of mixed ferrous/ferric salts along with oleic acid as a coating agent at 70˚C; (ii) Fe3O4 nanoparticles prepared by hydrolysis of aqueous solution of ferrous/ferric salts with potassium hydroxide at room temprature. Scanning electron microscopy (SEM) showed that the PVDF magnetic nanocomposite had a porous structure with Fe3O4 nanoparticles dispersed inside the porous polymer matrix. The presence of crystalline magnetite within the polymer matrix was confirmed by X-Ray diffraction method...

Cooperative Search and Localization of Mobile RF Ground Targets, Using a Group of UAVs

, M.Sc. Thesis Sharif University of Technology Effati, Meysam (Author) ; Nobahari, Hadi (Supervisor)

Abstract

In this project, a method for cooperative search and localization of RF ground moving targets by a group of UAVs is developed. It should be noted that UAVs are just equipped with GPS and directional sensors. Since there is fuel constraint for UAVs, they take fuel from a tanker whenever they require. Moreover, searching method enables the UAVs to see different parts of the desired area with almost uniform distribution. In addition, the proposed approach enables the UAVs to perform a local search with the aim of finding the targets having lost their signal during localization mode. Finally, based upon a fueling decision function the UAVs take turn, approach to the fuel tanker, and start...

Attitude Control of a 3DOF Quadrotor Stand Using Intelligent Back-stepping Approach

, M.Sc. Thesis Sharif University of Technology Abeshtan, Peyman (Author) ; Nobahari, Hadi (Supervisor)

Abstract

In this research a novel intelligent back-stepping control method is developed. This method is robust to sensor noise and external disturbances. In addition, the controller is robust under model uncertainty. This controller does not need precise knowledge of system parameters. This method is based on three methods of: back-stepping control, least squares estimation and a fuzzy compensator. This controller is used to control quadrotor stand witch is like an inverse pendulum. In quadrotor stand modeling, the inverse pendulum effect is considered too, witch is one of the innovations of the research. By doing various simulations, the validity of controller is tested. Also the performance of the...

Cooperative Search and Localization of Aerial Targets, Using a Group of Fixed Wing UAVs

, M.Sc. Thesis Sharif University of Technology pourhaji, Amir (Author) ; Nobahari, Hadi (Supervisor)

Abstract

Topic that is investigated in this article include identify and localization a number of aerial target penetrating into a protected by area by a swarm of UAVs is fixed wing. UAVs do not have any prior notice of positioning targets. In addition, it is assumed that lacks any radiation exploitable targets and thus use UAVs for Targets Detection from an active radar system. Obviously this article focus on developing a guidance algorithm UAVs to this particular issue and also as the targets participatory is localization algorithm. In addition, extraction type and performance characteristics radar system required and also performance characteristics of the class of UAVs, which is suitable to...

A New Method for Integrated Controller and Observer Design of a Nonlinear System Using Genetic Programming

, M.Sc. Thesis Sharif University of Technology Khosroabadi, Saleh (Author) ; Nobahari, Hadi (Supervisor)

Abstract

The purpose of this paper is to design an integrated controller and observer (ICO) for a nonlinear system using genetic programming. ICO is a function that constructs control command directly from the measured state variables of the system. It means that, this function should imitate the behavior of the observer and controller and control the system with acceptable performance in different initial conditions, at the presence of disturbances and system uncertainties. The complexity of this design method, is not related to the complexity of the plant, in fact, the complexity in plant just effects at run time, but the design procedure does not change. So, if exact model of plant exist, using...

Development of Integrated Model of the Wastewater and Organic Solid Waste Flows to Minimize Environmental Impacts and Maximize Energy Recovery for a Residential Building

, M.Sc. Thesis Sharif University of Technology Hadi, Hamid (Author) ; Avami, Akram (Supervisor)

Abstract

Nowdays much of the organic solid waste and wastewater is buried using centralized and traditional methods. This leads to many problems, including groundwater pollution, methane emissions into the atmosphere and rapid transmission of disease. In order to avoid these problems, using a decentralized approach can be a good solution. In this study, recovery of organic waste and wastewater of residential buildings using anaerobic digester as a decentralized way, have been examined. Using experiments, the optimum mass ratio of organic solid waste and wastewater is obtained as 80% and 20% respectively. Biogas production model is developed using mass balance and Balance of electrons in redox...

Parallel Multi-disciplinary Design Optimization of a Guided Flying Vehicle

, M.Sc. Thesis Sharif University of Technology Darabi, Davoud (Author) ; Nobahari, Hadi (Supervisor)

Abstract

Multi-disciplinary design optimization (MDO) of a surface to air flying vehicle has been done in this research, on the basis of flight simulation. The MDO problem have five disciplines consists of aerodynamic, propulsion, guidance, control, and fire control. Multiple campaign scenarios are defined. The MDO problem has 31 design variables and two objective functions. The objective functions are flying vehicle weight and miss distance. A new meta-heuristic algorithm has been designed to solve multi-objective optimization problems. The new algorithm has been called Multi-objective Adaptive Real-coded Memetic Algorithm (MARCOMA). The MARCOMA can solve large-scale and multi-objective problems and...

Dynamic Modelling and Nonlinear Control of a Hybrid Powered Hexarotor for Precise Trajectory Tracking

, M.Sc. Thesis Sharif University of Technology Saadat, Sepehr (Author) ; Nobahari, Hadi (Supervisor)

Abstract

In this Thesis, an unmanned multicopter with a new structure is modeled and a nonlinear controller is designed for it to track the trajectories precisely. The multicopter in this thesis, has six propellers with a hybrid propulsion system (a combination of fuel and electric propulsion system) that has the ability to carry more payload and maintain more flight duration compared to electric multicopters. In the beginning, the performance characteristics and technical specifications of the hexacopter are presented. For modeling, first the equations of six degrees of freedom movement of the hexacopter are derived by the Newton-Euler method. In the next step, the forces and torques applied to the...

Theoretical Investigation of Ab-initio MD Approach to Increase the Efficiency and Accuracy of VCD Spectrum Calculation

, M.Sc. Thesis Sharif University of Technology Hadi, Hossein (Author) ; Jamshidi, Zahra (Supervisor)

Abstract

Understanding of the Molecules is the main purpose of the chemistry. Ab-initio molecular dynamics (AIMD) as a branch of the computational chemistry, tries to give us a deep comprehension of the molecule, and its chemical, physical and optical activities. This comprehension, relies on the accuracy of quantum mechanics, in addition to the speed of the classical mechanics. The mixing of the quantum mechanics and the classical mechanics could simulate activities of the atoms in the time-domain, provided the mixing is done with precaution. This, in turn, helps us to forecast the response of a molecule in different situations, and also translating the macroscopic phenomena in a nanoscopic...

Developing a Heuristic Filter Utilizing Firefly Optimization Algorithm: A Case Study on State Estimation of a Slung Payload from a Quadrotor

, M.Sc. Thesis Sharif University of Technology Raoufi, Mohsen (Author) ; Nobahari, Hadi (Supervisor)

Abstract

The aim of the present thesis is to develop a novel heuristic filter by utilizing Firefly Optimization Algorithm for state estimation of nonlinear, non-Gaussian systems. The proposed filter formulates the estimation problem as a dynamic, stochastic one. The swarm intelligence of the fireflies enables the filter to find and track the best estimation. To estimate the states of a system, the model of the system is required. Hence, an 8-DoF quadrotor with slung payload system, as a case study, is modeled by the tensor method. In this case, as a highly nonlinear system, in order not to rely on extra sensors for monitoring swing-angle, the estimation of payload states is needed. In this regard,...