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Articles 1 - 24 of 24
Full-Text Articles in Engineering
Probe-Pulse Optimization For Nonresonant Suppression In Hybrid Fs/Ps Coherent Anti-Stokes Raman Scattering At High Temperature, Joseph D. Miller, Mikhail N. Slipchenko, Terrence R. Meyer
Probe-Pulse Optimization For Nonresonant Suppression In Hybrid Fs/Ps Coherent Anti-Stokes Raman Scattering At High Temperature, Joseph D. Miller, Mikhail N. Slipchenko, Terrence R. Meyer
Terrence R Meyer
Hybrid femtosecond/picosecond coherent anti-Stokes Raman scattering (fs/ps CARS) offers accurate thermometry at kHz rates for combustion diagnostics. In high-temperature flames, selection of probe-pulse characteristics is key to simultaneously optimizing signal-to-nonresonant-background ratio, signal strength, and spectral resolution. We demonstrate a simple method for enhancing signal-to-nonresonant-background ratio by using a narrowband Lorentzian filter to generate a time-asymmetric probe pulse with full-width-half-maximum (FWHM) pulse width of only 240 fs. This allows detection within just 310 fs after the Raman excitation for eliminating nonresonant background while retaining 45% of the resonant signal at 2000 K. The narrow linewidth is comparable to that of a …
Stochastic Modeling And Optimization Of Multi-Plant Capacity Planning Problem, Anoop Verma, Nagesh Shukla, S.K Tyagi, Nishikant Mishra
Stochastic Modeling And Optimization Of Multi-Plant Capacity Planning Problem, Anoop Verma, Nagesh Shukla, S.K Tyagi, Nishikant Mishra
Nagesh Shukla
n this paper the problem of capacity planning under risk from demand and price/cost uncertainty of the finished products is addressed. The deterministic model is extended into a two-stage stochastic model with fixed recourse by means of various expected levels of demand as random. A recourse penalty is also included in the objective for both shortage and surplus in the finished products. The model is analyzed to quantify the risk using Markowitz mean-variance model.
Particle Swarm Optimization Approach For Maximizing The Yield Of A Coal Preparation Plant, Vishal Gupta, Hussain Unjawala, Ajay Mohan Mahajan, Manoj Mohanty
Particle Swarm Optimization Approach For Maximizing The Yield Of A Coal Preparation Plant, Vishal Gupta, Hussain Unjawala, Ajay Mohan Mahajan, Manoj Mohanty
Dr. Ajay Mahajan
This paper presents the use of particle swarm optimization to maximize the clean coal yield of a coal preparation plant that typically has multiple cleaning circuits that produce the same product quality so that the blend of clean coal meets the targeted product quality contraints. Particle swarm is used for the yield optimization while satisfying multiple product quality restraints. The results show a 2.73% increase in the yield can be achieved leading to additional revenue of $5,460,000 per annum for a plant producing 10 million tons of clean coal per year without significantly adding to the implementation/operation cost.
Optimizing The Robot Arm Movement Time Using Virtual Reality Robotic Teaching System
Optimizing The Robot Arm Movement Time Using Virtual Reality Robotic Teaching System
Faculty of Engineering University of Malaya
Robots play an important role in performing operations such as welding, drilling and screwing parts in manufacturing. Optimizing the robot arm movement time between different points is an important task which will minimize the make-span and maximize the production rate. But robot programming is a complex task whereby the user needs to teach and control the robot in order to perform a desired action. In order to address the above problem, an integrated 3-dimensional (3D) simulation software and virtual reality (VR) system is developed to simplify and speed up tasks and therefore enhance the quality of manufacturing processes. This system …
Stiffness Performance Of Polyethylene Terephthalate Modified Asphalt Mixtures Estimation Using Support Vector Machine-Firefly Algorithm
Faculty of Engineering University of Malaya
Predicting asphalt pavement performance is an important matter which can save cost and energy. To ensure an accurate estimation of performance of the mixtures, new soft computing techniques can be used. In this study, in order to estimate the stiffness property of Polyethylene Terephthalate (PET) modified asphalt mixture, different soft computing methods were developed, namely: support vector machine-firefly algorithm (SVM-FFA), genetic programming (GP), artificial neural network (ANN) and support vector machine. The support vector machine-firefly algorithm (SVM-FFA) is a metaheuristic search algorithm developed according to the socially dashing manners of fireflies in nature. To develop the models, experiments were performed. …
A New Low-Profile Inverted A-Shaped Patch Antenna For Multi-Band Operations
A New Low-Profile Inverted A-Shaped Patch Antenna For Multi-Band Operations
Faculty of Engineering University of Malaya
This paper presents the design and analysis of a compact modified inverted-A shape multi-band patch antenna for WiMAX and C-band telecommunication satellite applications. The proposed antenna has simple geometrical structure which consist of 20 mm x 20 mm radiating patch with slot loading and fed by 4 mm long microstrip line. The proposed antenna is designed and analyzed by using commercially available full-wave 3D high frequency electromagnetic simulator namely Ansys HFSS. The optimized design of the proposed multi-band patch antenna is fabricated on 1.6 mm thick fiberglass polymer resin dielectric material substrate with reduced ground plane by using in-house PCB …
Fuzzy Logic Based Model For Predicting Surface Roughness Of Machined Al-Si-Cu-Fe Die Casting Alloy Using Different Additives-Turning
Faculty of Engineering University of Malaya
This paper presents a fuzzy logic artificial intelligence technique for predicting the machining performance of Al-Si-Cu-Fe die casting alloy treated with different additives including strontium, bismuth and antimony to improve surface roughness. The Pareto-ANOVA optimization method was used to obtain the optimum parameter conditions for the machining process. Experiments were carried out using oblique dry CNC turning. The machining parameters of cutting speed, feed rate and depth of cut were optimized according to surface roughness values. The results indicated that a cutting speed of 250 m/min, a feed rate of 0.05 mm/rev, and a depth of cut of 0.15 mm …
Estimation Of The Effect Of Catalyst Physical Characteristics On Fenton-Like Oxidation Efficiency Using Adaptive Neuro-Fuzzy Computing Technique
Faculty of Engineering University of Malaya
Catalyst size, which determines surface area, is one of the major factors in catalytic performance. In this study, response surface methodology (RSM) and an adaptive neuro-fuzzy inference system (ANFIS) were applied to quantify the effects of physical characteristics of magnetite on Fenton-like oxidation efficiency of methylene blue. For this purpose, two magnetite samples (M and N) were used and characterized by XRD, BET surface area, particle size analyzer and FE-SEM. Central composite design (CCD) was applied to design the experiments, develop regression models, optimize and evaluate the individual and interactive effects of five independent variables: H2O2 and catalyst concentrations, pH, …
Synthesis And Optimization Of Pedot:Pss Based Ink For Printing Nanoarrays Using Dip-Pen Nanolithography, Michal Wagner, Cathal O'Connell, David G. Harman, Ryan Sullivan, Ari Ivaska, Michael J. Higgins, Gordon G. Wallace
Synthesis And Optimization Of Pedot:Pss Based Ink For Printing Nanoarrays Using Dip-Pen Nanolithography, Michal Wagner, Cathal O'Connell, David G. Harman, Ryan Sullivan, Ari Ivaska, Michael J. Higgins, Gordon G. Wallace
Gordon Wallace
Due to the current interest in organic printable electronics, Dip-Pen Nanolithography (DPN) is increasingly being explored as a method to pattern electroactive materials such as conducting polymers (CPs) on the micro- and nanoscale. In general, printing process depends strongly on the ink-substrate properties and fundamental forces required to drive and stabilize the ink transfer to the substrate. Controlling these parameters is especially difficult when operating under the nanometer confinements of the DPN probe. For the printing of CPs, one step towards addressing these challenges is rational ink design, as the use of existing commercial-based inks may not be suitable for …
Comparison Study Of Different Ionic Liquid Pretreatments In Maximizing Total Reducing Sugars Recovery, Kiat Moon Lee, Gek Cheng Ngoh Dr, Adeline Seak May Chua Dr, Li Wan Yoon, Teck Nam Ang Dr., Min Gyu Lee Prof
Comparison Study Of Different Ionic Liquid Pretreatments In Maximizing Total Reducing Sugars Recovery, Kiat Moon Lee, Gek Cheng Ngoh Dr, Adeline Seak May Chua Dr, Li Wan Yoon, Teck Nam Ang Dr., Min Gyu Lee Prof
Teck Nam Ang Dr.
A process scheme combining the most suitable ionic liquid pretreatment, followed by solid acid and enzymatic saccharification was used to maximize the reducing sugars recovery from sago waste. Three types of ionic liquids, i.e. 1-butyl-3-methylimidazolium chloride ([BMIM]Cl), 1- ethyl-3-methylimidazolium acetate ([EMIM][OAc]) and 1-ethyl-3-methylimidazolium diethyl phosphate ([EMIM][(EtO)2PO2]) were evaluated based on their performance in terms of the total reducing sugars recovery, chemical cost, and pretreatment energy requirement. The results showed that all the ionic liquids assisted the saccharification processes by dissolving and depolymerizing the carbohydrates of the sago waste into shorter chain soluble oligosaccharides, as well as disrupting the biomass structure …
Wind Power Electric Systems: Modelization, Control And Optimization, Djamila Rekioua Pr
Wind Power Electric Systems: Modelization, Control And Optimization, Djamila Rekioua Pr
REKIOUA Djamila Dr
The book is organized through seven chapters as follows: • Chapter 1 is intended as an introduction to the subject. It defines the wind process, introduces the main meteorological elements, the wind velocity, and presents an overview of wind systems (stand-alone systems and grid connected systems). This chapter includes also pre-sizing and maintenance of wind systems. • Chapter 2 focuses on wind energy conversion and power electronics modeling. The different structures of converters used in wind systems are presented. Some applications are given under Matlab/Simulink. • In Chapter 3, a detailed review on the most used algorithms to track the …
Voltage Security Constrained Reactive Power Optimization Incorporating Wind Generation, L G. Meegahapola, E Vittal, A Keane, D Flynn
Voltage Security Constrained Reactive Power Optimization Incorporating Wind Generation, L G. Meegahapola, E Vittal, A Keane, D Flynn
Dr Lasantha G Meegahapola
This paper presents a comparative analysis between conventional optimal power flow (OPF) and voltage constrained OPF strategies with wind generation. The study has been performed using the New England 39 bus system with 12 doublyfed induction generator (DFIG) based wind farms installed across the network. A voltage security assessment is carried out to determine the critical wind farms for voltage stability enhancement. The power losses and individual wind farm reactive power generation have been compared with and without voltage stability constraints imposed on the OPF simulation. It is shown that voltage constrained OPF leads to much greater active power losses …
Synthesis And Optimization Of Fluorine-Free Y And Cu Precursor Solution For Mod Processing Of Ybco Coated Conductor, Jaimoo Yoo, Young-Kuk Kim, Kookchae Chung, Jaewoong Ko, Xiaolin Wang, S X. Dou
Synthesis And Optimization Of Fluorine-Free Y And Cu Precursor Solution For Mod Processing Of Ybco Coated Conductor, Jaimoo Yoo, Young-Kuk Kim, Kookchae Chung, Jaewoong Ko, Xiaolin Wang, S X. Dou
Shi Xue Dou
MOD solutions for YBCO coated conductors were synthesized with fluorine-free Y & Cu precursor. The fluorine content in the precursor solution was significantly reduced and a fast calcination profile was realized. A crack-free & thick precursor film was successfully obtained just after less than 2 hours of calcination in wet O2 atmosphere. Optimization of the precursor solution with Sm addition enables further improvement of thickness and uniformity of precursor films. The calcinated precursor film was successfully converted to dense and uniform YBCO film after annealing in wet Ar/O2 atmosphere. The measured critical current value was about 273 A/cm-w (Jc ~ …
Optimization Of Welding Parameters For Repairing Nial Bronze Components, Huijun Li, Daniel Grudgings, Nathan P. Larkin, John Norrish, Mark Callaghan, Lenka Kuzmikova
Optimization Of Welding Parameters For Repairing Nial Bronze Components, Huijun Li, Daniel Grudgings, Nathan P. Larkin, John Norrish, Mark Callaghan, Lenka Kuzmikova
Nathan Larkin
The objective of this study is to determine an optimal welding procedure that can be implemented to repair damaged Nickel Aluminium Bronze (NAB) components. NAB is commonly used in marine applications where components are subject to a constant corrosive environment and high stresses. Research into ideal NAB microstructure for a marine application, was performed in order to gain a baseline for experimental analysis of potential welding procedures. The results indicated that the welding repair can be performed with a wide range of heat input. The effect of post-weld heat treatment (PWHT) on the microstructure and mechanical properties in the heat …
Multiobjective Plan Selection Optimization For Traffic Responsive Control, Montasir M. Abbas, Anuj Sharma
Multiobjective Plan Selection Optimization For Traffic Responsive Control, Montasir M. Abbas, Anuj Sharma
Anuj Sharma
Optimal coordination of traffic signals requires proper activation of timing plans to match current traffic conditions. One of the greatest challenges in configuring a traffic responsive plan selection control mode is how to select only n number of timing plans (restricted by traffic controller memory limitations) to address possibly all traffic conditions/states that can be encountered in the field, for a specific site, but most importantly, how to associate each of these traffic conditions to one of the n timing plans stored in the traffic controller. This paper uses a multiobjective non-dominated sorting genetic algorithm to (1) select the best …
Blind Source Separation Based On Time-Domain Optimization Of A Frequency-Domain Independence Criterion, Tiemin Mei, Jiangtao Xi, Fuliang Yin, A. Mertins, Jose F. Chicharo
Blind Source Separation Based On Time-Domain Optimization Of A Frequency-Domain Independence Criterion, Tiemin Mei, Jiangtao Xi, Fuliang Yin, A. Mertins, Jose F. Chicharo
Professor Joe F. Chicharo
A new technique for the blind separation of convolutive mixtures is proposed in this paper. Inspired by the works of Amari, Sabala , and Rahbar, we firstly start from the application of Kullback-Leibler divergence in frequency domain, and then we integrate Kullback-Leibler divergence over the whole frequency range of interest to yield a new objective function which turns out to be time-domain variable dependent. In other words, the objective function is derived in frequency domain which can be optimized with respect to time domain variables. The proposed technique has the advantages of frequency domain approaches and is suitable for very …
Analysis Of Jet Characteristics And Structural Optimization Of A Liquamatic Fire Water Monitor With Self-Swinging Mechanism, Guoliang Hu, Ming Long, Juxing Liang, Weihua Li
Analysis Of Jet Characteristics And Structural Optimization Of A Liquamatic Fire Water Monitor With Self-Swinging Mechanism, Guoliang Hu, Ming Long, Juxing Liang, Weihua Li
Professor Weihua Li
This paper presents analysis and optimization of a liquamatic fire water monitor with a novel self-swinging mechanism. The design of the self-swinging mechanism has adopted a four-bar linkage driven by an impeller. The Fluent software was used to simulate the internal flow performance of the fire water monitor. In particular, the effects of the cross-sectional shape, diameters of the monitor body, inlet water pressure, and drive set of the self-swinging mechanism on the jet characteristics were analyzed. These analyses have led to optimal structural parameters of the flow channel. A prototype of the fire ware monitor was manufactured, and the …
Two-Step Optimal Thermal Generation Scheduling, B Fardanesh, F. Eugenio Villaseca
Two-Step Optimal Thermal Generation Scheduling, B Fardanesh, F. Eugenio Villaseca
F. Eugenio Villaseca
A new approach to the solution of the optimal thermal generation scheduling problem is presented. The problem is solved in two steps. As a first step, the optimal production schedule for the next day is obtained based on a daily load forecast, reserve capacity requirements, and present status of generating units. The second-step algorithm uses the results of the first step and adjusts the previous schedule to meet new constraints developed during the course of the day. Variable truncation dynamic programming is proposed as a new method to reduce computation effort. To eliminate the need for solving the entire problem …
Joint Metering And Conflict Resolution In Air Traffic Control, Jerome Le Ny, George J. Pappas
Joint Metering And Conflict Resolution In Air Traffic Control, Jerome Le Ny, George J. Pappas
George J. Pappas
This paper describes a novel optimization-based approach to conflict resolution in air traffic control, based on geometric programming. The main advantage of the approach is that Geometric Programs (GPs) can also capture various metering directives issued by the traffic flow management level, in contrast to most recent methods focusing purely on aircraft separation issues. GPs can also account for some of the nonlinearities present in the formulations of conflict resolution problems, while incurring only a small penalty in computation time with respect to the fastest linear programming based approaches. Additional integer variables can be introduced to improve the quality of …
Joint Metering And Conflict Resolution In Air Traffic Control, Jerome Le Ny, George J. Pappas
Joint Metering And Conflict Resolution In Air Traffic Control, Jerome Le Ny, George J. Pappas
George J. Pappas
This paper describes a novel optimization-based approach to conflict resolution in air traffic control, based on geometric programming. The main advantage of the approach is that Geometric Programs (GPs) can also capture various metering directives issued by the traffic flow management level, in contrast to most recent methods focusing purely on aircraft separation issues. GPs can also account for some of the nonlinearities present in the formulations of conflict resolution problems, while incurring only a small penalty in computation time with respect to the fastest linear programming based approaches. Additional integer variables can be introduced to improve the quality of …
Joint Metering And Conflict Resolution In Air Traffic Control, Jerome Le Ny, George J. Pappas
Joint Metering And Conflict Resolution In Air Traffic Control, Jerome Le Ny, George J. Pappas
George J. Pappas
This paper describes a novel optimization-based approach to conflict resolution in air traffic control, based on geometric programming. The main advantage of the approach is that Geometric Programs (GPs) can also capture various metering directives issued by the traffic flow management level, in contrast to most recent methods focusing purely on aircraft separation issues. GPs can also account for some of the nonlinearities present in the formulations of conflict resolution problems, while incurring only a small penalty in computation time with respect to the fastest linear programming based approaches. Additional integer variables can be introduced to improve the quality of …
Economic Analysis Of End-Of-Life Computer Systems In Educational Institutions, Elif A. Kizilkaya, Surendra M. Gupta, Dincer Mehmet
Economic Analysis Of End-Of-Life Computer Systems In Educational Institutions, Elif A. Kizilkaya, Surendra M. Gupta, Dincer Mehmet
Surendra M. Gupta
In this paper we address the operational and economical aspects of EOL computer systems at educational institutions. To this end we present an actual case study of a major university in Boston and provide an economical analysis of different options such as disposal, disassembly, recycling, reuse and re-sale of these systems. We recommend a new procedure that will improve the collection and handling processes leading to a structured decision making methodology.
Inventory Balancing Of Post-Usage Components Of A Disassembly Line, Surendra M. Gupta, Badr O. Johar
Inventory Balancing Of Post-Usage Components Of A Disassembly Line, Surendra M. Gupta, Badr O. Johar
Surendra M. Gupta
In recent years, disassembly has gained a lot of attention due to its role in efficiently recovering valuable materials, parts, and subassemblies from end of life (EOL) products. This is due to the rigid environmental legislation, the economical and environmental benefits from reusing primary materials instead of virgin resources and the increase in environmental awareness and concerns of the consumers. However, the practice of recovering components and materials is challenging, as there are many associated complications that are unique to the disassembly process such as monitoring and controlling the inventory of core products and disassembled parts and the ability to …
A Method Of Minimizing The Power Losses In An Induction Motor With A Squirrel-Cage With Vector Control, Boukhemis Chetate, Aissa Kheldoun
A Method Of Minimizing The Power Losses In An Induction Motor With A Squirrel-Cage With Vector Control, Boukhemis Chetate, Aissa Kheldoun
Boukhemis Chetate
An approach to optimizing the flux linkage of the rotor of an induction motor is considered when the motor operates in a vector control mode with indirect orientation in the direction of the field. In this system, the expression for the frequency of the rotor e.m.f. contains the rotor winding impedance; this impedance must therefore be precisely estimated in real time. It is proposed that this should be done using a fuzzy-logic adaptation mechanism. The results of using such a mechanism in a physical model confirm its effectiveness. Key words: induction motor, rotor, vector control, fuzzy logic.