Mechanical Engineering Commons^™

Kinematic Control Of Redundant Mobile Manipulators, Mustafa Mashali

USF Tampa Graduate Theses and Dissertations

A mobile manipulator is a robotic arm mounted on a robotic mobile platform. In such a system, the degrees of freedom of the mobile platform are combined with that of the manipulator. As a result, the workspace of the manipulator is substantially extended. A mobile manipulator has two trajectories: the end-effector trajectory and the mobile platform trajectory. Typically, the mobile platform trajectory is not defined and is determined through inverse kinematics. But in some applications it is important to follow a specified mobile platform trajectory. The main focus of this work is to determine the inverse kinematics of a mobile …

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 …

Role Of Thermal Conductivity For Thermoelectrics With Finite Contacts, Yee Rui Koh, Kazuaki Yazawa, Ali Shakouri

International Thermal Conductivity Conference (ITCC) and the International Thermal Expansion Symposium (ITES)

The role of thermal conductivity in the performance of thermoelectric (TE) devices as compared to other material properties such as Seebeck coefficient and the electrical conductivity will be discussed. A TE energy conversion system that includes thermal contacts for the hot side and the cold side with finite heat transfer performances is considered. Some of the trends in electronics cooling applications have been described. In this article, the effect of material properties as a function of energy current flow direction will be focused.

TEs have an advantage as solid-state heat energy conversion devices especially for applications with spatial constraints. A …

Optimization Of Blalock-Taussig Shunt And Anastomotic Geometry For Vascular Access Fistula Using A Genetic Algorithm, Guangyu Bao

McKelvey School of Engineering Theses & Dissertations

Blalock-Taussig (BT) shunts are used for defects that affect the flow of blood from the right ventricle, through the pulmonary artery, and to the lungs. Arteriovenous (AV) fistula is one type of vascular access which is a surgically created vein used to remove and return blood during hemodialysis. Plastic grafts used in the above two reconstructions may result in areas of non-physiologic flow in the grafts leading to risk of stenosis (blocked area) and thrombosis, which is the single major cause for access morbidity. The focus of this thesis is to study BT shunts and anastomoses models using Computational Fluid …

Optimization In The Simulation Of Jammed Polyhedral Particles, Joseph W. Mynhier, Ishan Srivastava, Timothy S. Fisher

The Summer Undergraduate Research Fellowship (SURF) Symposium

Energy loss due to poor transport properties in electrically and thermally conducting materials, such as battery electrodes and thermoelectric composites, contributes to the energy inefficiency of electronic devices. For conductive materials composed of granular materials, particle-particle contact topology strongly governs the efficiency of energy transfer. Although there is a large body of existing work on the arrangements made by granular materials comprised of spherical particles, less is known about the mechanically stable arrangements of granular materials made of convex polyhedra. This project seeks to create a computer simulation of the solidification of convex polyhedra from a diffuse state into a …

Comparison Of Two Wake Models For Use In Gradient-Based Wind Farm Layout Optimization, Jared Thomas, Eric Tingey, Andrew Ning

Faculty Publications

Wind farm layout has a significant impact on the productivity of a wind farm. To ensure that the turbines are placed in the most advantageous arrangement, optimization algorithms are often used during the layout design process. Depending on the wake model used for the optimization, optimizing the layout can be time intensive or potentially inaccurate. In this paper we present a comparison of optimization results using two simple wake models, the FLORIS model and the Jensen model. Results highlight some of the key similarities and differences of layout optimization results when different wake models are used.

Strasbaugh Nonconforming Report Optimization, Eden Andersen, Angela Asgekar, Rebecca Gregg

Industrial and Manufacturing Engineering

This paper strives to convey the problems and proposed solutions for Strasbaugh’s Nonconforming Report (NCR) Optimization. Strasbaugh is a world leader in silicon wafer polisher and grinder technologies. After a significant down size to the company parts they used to manufacture now have to be purchased, and many of these incoming parts do not conform to Strasbaugh’s high standards. This has led to an increase in NCRs that need to be processed, which takes up time, resources and money.

The objective therefore became to update the multi-sheet carbon copy paper system to better optimize the use of these reports and …

The Arched Flexure Vsa: A Compact Variable Stiffness Actuator With Large Stiffness Range, Joseph M. Schimmels, Daniel Garces

Mechanical Engineering Faculty Research and Publications

The high stiffness of conventional robots is beneficial in attaining highly accurate positioning in free space. High stiffness, however, limits a robot's ability to perform constrained manipulation. Because of the high stiffness, geometric conflict between the robot and task constraints during constrained manipulation can lead to excessive forces and task failure. Variable stiffness actuators can be used to adjust the stiffness of robot joints to allow high stiffness in unconstrained directions and low stiffness in constrained directions. Two important design criteria for variable stiffness actuation are a large range of stiffness and a compact size. A new design, the Arched …

Active Control Of The Human Voice From A Sphere, Monty J. Anderson

Theses and Dissertations

This work investigates the application of active noise control (ANC) to speech. ANC has had success reducing tonal noise. In this work, that success was extended to noise that is not completely tonal but has some tonal elements such as speech. Limitations such as causality were established on the active control of human speech. An optimal configuration for control actuators was developed for a sphere using a genetic algorithm. The optimal error sensor location was found from exploring the nulls associated with the magnitude of the radiated pressure with reference to the primary pressure field. Both numerically predicted and experimentally …

A Multi-Objective Optimization Method For Maximizing The Value Of System Evolvability Under Uncertainty, Jason Daniel Watson

Theses and Dissertations

System evolvability is vital to the longevity of large-scale complex engineered systems. The need for evolvability in complex systems is a result of their long service lives, rapid advances to their integrated technologies, unforeseen operating conditions, and emerging system requirements. In recent years, quantifiable metrics have been introduced for measuring the evolvability of complex systems based on the amount of excess capability in the system. These metrics have opened opportunities for optimization of systems with evolvability as an objective. However, there are several aspects of such an optimization that require further consideration. For example, there is a trade-off between the …

Optimization Of Threshold Values For Estimators Based On Single-Bit Quantized Sensors Using Genetic Algorithms, Nishant Unnikrishnan, Ajay Mahajan, Antonios Mengoulis, R. Viswanathan

Dr. Ajay Mahajan

The paper considers the problem of signal parameter estimation using a collection of distributed sensors called a sensor pack. Each sensor quantizes its data to one-bit information and sends it to a fusion processor for the estimation of the parameter. Estimation of a constant signal in additive noise is considered. Estimators are formulated based on one-bit sensor data and their mean squared error (MSE) performances are evaluated through simulation studies. It is shown that selecting certain threshold values for quantizing the sensor outputs can lower the MSE. Genetic algorithms are used to find the optimal threshold values for the sensors. …

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.

Genetic Algorithms — A Novel Technique To Optimize Coal Preparation Plants, Vishal Gupta, Manoj Mohanty, Ajay Mahajan, S. Biswal

Dr. Ajay Mahajan

A coal preparation plant typically operates with multiple cleaning circuits based on the particle size distribution of run-of-mine coal. Clean coal product from a plant commonly has to satisfy multiple product quality constraints, including product ash, product sulfur, heating value, moisture content, etc. Numerous studies in the past illustrate that the optimal yield of the plant can be obtained by operating each circuit to produce the same incremental product quality. This equal incremental product quality approach optimizes the plant yield considering only one product quality at a time. Thus, when required to simultaneously satisfy multiple product quality constraints, the process …

Performance Optimization Of A Coal Preparation Plant Using Genetic Algorithms, Vishal Gupta, Manoj Mohanty, Ajay Mahajan, Surendra Biswal

Dr. Ajay Mahajan

A coal preparation plant typically has multiple cleaning circuits based on size of coal particles. The traditional way of optimizing the plant output and meeting the product constraints such as ash, sulfur and moisture content is to equalize the average product quality from each circuit. The present study includes multiple incremental product quality approach to optimize the clean coal recovery while satisfying the product constraints. The plant output was optimized at the given constraints of 7.5% ash and 1.3% sulfur. It was observed that utilizing incremental product quality process gives 2.13% higher yield which can generate additional revenue of $4,260,000 …

Energy And Exergy Analysis Of Kalina Cycle For The Utilization Of Waste Heat In Brine Water For Indonesian Geothermal Field, Nasruddin Nasruddin, Agus Noor Sidiq, Abdulmajeed Mohamad, Rama Usvika

Makara Journal of Technology

The utilization of waste heat in a power plant system—which would otherwise be released back to the environment—in order to produce additional power increases the efficiency of the system itself. The purpose of this study is to present an energy and exergy analysis of Kalina Cycle System (KCS) 11, which is proposed to be utilized to generate additional electric power from the waste heat contained in geothermal brine water available in the Lahendong Geothermal power plant site in North Sulawesi, Indonesia. A modeling application on energy and exergy system is used to study the design of thermal system which uses …

Multiple-Objective Optimization In Precision Laser Cutting Of Different Thermoplastics

Faculty of Engineering University of Malaya

Thermoplastics are increasingly being used in biomedical, automotive and electronics industries due to their excellent physical and chemical properties. Due to the localized and non-contact process, use of lasers for cutting could result in precise cut with small heat-affected zone (HAZ). Precision laser cutting involving various materials is important in high-volume manufacturing processes to minimize operational cost, error reduction and improve product quality. This study uses grey relational analysis to determine a single optimized set of cutting parameters for three different thermoplastics. The set of the optimized processing parameters is determined based on the highest relational grade and was found …

Dimensional Synthesis Of Four Bar Mechanism Using Genetic Algorithm, Innovative Research Publications Irp India, S. S. Shete, S. A. Kulkarni

Innovative Research Publications IRP India

The dimensional synthesis is done by using Genetic Algorithm to achieve a desired trajectory. Three problems are analyzed having different curvature. The program is authored in MATLAB® 2010a. The error is seen to be in the permissible prescribed limit. The prototyping of straight line trajectory analysis is also done in ADAMS®

Research On Optimization Of Plunge Centerless Grinding Process Using Genetic Algorithm And Response Surface Method, Innovative Research Publications Irp India, Phan Bui Khoi, Do Duc Trung, Ngo Cuong, Nguyen Dinh Man

Innovative Research Publications IRP India

This paper presents the research on optimization of plunge centerless grinding process when grind 20X – carbon infiltration steel (ГOCT standard - Russia) to achieve minimum of roundness error value. The input parameters are center height angle of the workpiece (  ), longitudinal grinding wheel dressing feed-rate ( Ssd ), plunge feed-rate ( k S ) and control wheel velocity ( dd v ). Using the result of 29 runs in Central Composite Design matrix to given the second order roundness error model. Genetic algorithm and Response surface method were used to focus on determination of optimum centerless grinding …

Electrospinning Of Polymethyl Methacrylate Nanofibers: Optimization Of Processing Parameters Using The Taguchi Design Of Experiments

Faculty of Engineering University of Malaya

The effects of polymer concentration and electrospinning parameters on the diameter of electrospun polymethyl methacrylate (PMMA) fibers were experimentally investigated. It was also studied how the controlled factors would affect the output with the intention of finding the optimal electrospinning settings in order to obtain the smallest PMMA fiber diameter. Subsequently the solution feed rate, needle gauge diameter, supply voltage, polymer concentration and tip-to-collector distance were considered as the control factors. To achieve these aims, Taguchi's mixed-level parameter design (L-18) was employed for the experimental design. Optimal electrospinning conditions were determined using the signal-to-noise (S/N) ratio that was calculated from …

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 …

Effective Utilization Of Excess Energy In Standalone Hybrid Renewable Energy Systems For Improving Comfort Ability And Reducing Cost Of Energy: A Review And Analysis

Faculty of Engineering University of Malaya

One of the features that characterize renewable energy sources is their variability and intermittency. Intermittency covers both the predictable and unpredictable variations of their power outputs and uncertainty in the power availability. To overcome the drawback of intermittency, special design considerations should be taken into account. These additional design considerations increases the overall cost of the renewable energy systems. Adding storage system and/or backup source to the renewable sources is one of the measures used to guarantee the continuity of power supply to the loads, and therefore improve the reliability of the renewable energy systems. The operation of renewable energy …

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 …

Effect Of Alcohol-Gasoline Blends Optimization On Fuel Properties, Performance And Emissions Of A Si Engine

Faculty of Engineering University of Malaya

This study, as an observation, put its utmost effort to emphasize on the development of various physicochemical properties using multiple alcohols (C-2 to C-6) at different ratios compared to that of the conventional ethanol gasoline blend. To optimize the properties of multiple alcohol-gasoline blends, properties of each fuel were measured first. An optimization tool of Microsoft Excel "Solver" was used for obtaining the optimum blend. Using optimizing tool, three optimum blend ratios were selected which possessed maximum heating value (MaxH), maximum research octane number (MaxR) and maximum petroleum displacement (MaxD). These blends were used for testing in a four cylinder …

Optimizing Cutting Parameters In Inclined End Milling For Minimum Surface Residual Stress - Taguchi Approach

Faculty of Engineering University of Malaya

End milling is an important and common machining operation because of its versatility and capability to produce various profiles and curved surfaces. Inclined end milling possesses the capability to translate in all 3 axes but can perform the cutting operation in only 2 of the 3 axes at a time. This research work focuses on investigating the effect of machined surface inclination angle, axial depth of cut, spindle speed and feed rate for better surface integrity in inclined end milling process utilizing titanium coated carbide ball end mill. An optimization method known as Taguchi optimization was used in order to …

Review Of Improvements In Wire Electrode Properties For Longer Working Time And Utilization In Wire Edm Machining

Faculty of Engineering University of Malaya

Wire electrical discharge machining (WEDM) is an important technology, which demands high-speed cutting and high-precision machining to realize productivity and improved accuracy for manufacturing hard materials. WEDM has experienced explosive growth and complexity of equipment as well as rising demand for the basic process tool (the wire electrode). Greater taper angles, thicker workpieces, automatic wire threading, and long periods of unattended operation make the selection of the ideal wire a much more critical basis for achieving successful operation. This paper focuses on the evolution of EDM wire electrode technologies from using copper to the widely employed brass wire electrodes and …

Investigating The Electrical Discharge Machining (Edm) Parameter Effects On Al-Mg2si Metal Matrix Composite (Mmc) For High Material Removal Rate (Mrr) And Less Ewr-Rsm Approach

Faculty of Engineering University of Malaya

Al-Mg2Si composite is a new group of metalmatrix composites (MMCs). Electrical discharge machining (EDM) is a nonconventional machining process for machining electrically conductive materials regardless of hardness, strength and temperature resistance, complex shapes, fine surface finish/textures and accurate dimensions. A copper electrode and oil-based dielectric fluid mixed with aluminum powder were used. The polarity of electrode was positive. Response surface methodology (RSM) was used to analyze EDM of this composite material. This research illustrates the effect of input variables (voltage, current, pulse ON time, and duty factor) on material removal rate (MRR), electrode wear ratio (EWR), and microstructure changes. The …

Thermodynamic Analysis And Optimization Of Supercritical Carbon Dioxide Brayton Cycles, Mahmood Mohagheghi

Electronic Theses and Dissertations

The power generation industry is facing new challenging issues regarding accelerating growth of electricity demand, fuel cost and environmental pollution. These challenges accompanied by concerns of energy resources becoming scarce necessitate searching for sustainable and economically competitive solutions to supply the future electricity demand. To this end, supercritical carbon dioxide (S-CO2) Brayton cycles present great promise particularly in high temperature concentrated solar power (CSP) and waste heat recovery (WHR) applications. With this regard, this dissertation is intended to perform thorough thermodynamic analyses and optimization of S-CO2 Brayton cycles for both of these applications. A modeling tool has been developed, which …