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2012

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Articles 5581 - 5610 of 6303

Full-Text Articles in Engineering

The Effect Of Biodiesel Blends On A Multi-Cylinder Engine And The Impact On Aftertreatment, Amy Peterson Jan 2012

The Effect Of Biodiesel Blends On A Multi-Cylinder Engine And The Impact On Aftertreatment, Amy Peterson

Wayne State University Dissertations

Recently, topics including global warming, increased environmental awareness, recycling, and organically produced meat and vegetables have been prevalent in the media and research arenas. The rapidly increasing cost for fossil fuels and the pursuit of environmental conservation has brought about the interest in a renewable and clean burning fuel, specifically biodiesel. Biodiesel, or vegetable oil ester as it was originally referred to, has been improving and progressing since the early 1900's. Fortunately, significant advancement in the understanding of raw vegetable oil as a fuel as well as converting it to ethyl or methyl esters, now known as biodiesel, has been …

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Optimal Advance Detector Location For Green Termination Systems On High-Speed Isolated Rural Intersections, Lili Du, Anuj Sharma, Srinivas Peeta Jan 2012

Optimal Advance Detector Location For Green Termination Systems On High-Speed Isolated Rural Intersections, Lili Du, Anuj Sharma, Srinivas Peeta

Department of Civil and Environmental Engineering: Faculty Publications

This study seeks to identify the optimal location of an advance point traffic detector (APTD) to support green termination algorithms for enhanced dilemma zone protection systems at high-speed isolated signalized rural intersections. This is done by developing a nonlinear optimization model with the objective to maximize the opportunities to predict empty dilemma zones during a look-ahead time period subject to the prediction accuracy which is manifested through prediction efficiency and safety constraints in the model. The distance of the APTD from the stop bar of the intersection represents the decision variable. The Golden-Section line search algorithm combined with numerical integration …

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Methane And Carbon Dioxide Production From Simulated Anaerobic Degradation Of Cattle Carcasses, Qi Yuan, Samuel Saunders, Shannon L. Bartelt-Hunt Jan 2012

Methane And Carbon Dioxide Production From Simulated Anaerobic Degradation Of Cattle Carcasses, Qi Yuan, Samuel Saunders, Shannon L. Bartelt-Hunt

Department of Civil and Environmental Engineering: Faculty Publications

Approximately 2.2 million cattle carcasses require disposal annually in the United States. Land burial is a convenient disposal method that has been widely used in animal production for disposal of both daily mortalities as well as during catastrophic mortality events. To date, greenhouse gas production after mortality burial has not been quantified, and this study represents the first attempt to quantify greenhouse gas emissions from land burial of animal carcasses. In this study, anaerobic decomposition of both homogenized and unhomogenized cattle carcass material was investigated using bench-scale reactors. Maximum yields of methane and carbon dioxide were 0.33 and 0.09 m …

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Effects Of Inclusion Shapes Within Rigid Porous Materials On Acoustic Performance, Hyun Hong, Siu-Kit Lau Jan 2012

Effects Of Inclusion Shapes Within Rigid Porous Materials On Acoustic Performance, Hyun Hong, Siu-Kit Lau

Durham School of Architectural Engineering and Construction: Faculty Publications

The present study investigates the influence of various shapes of inclusions having same volume embedded in a porous rigid material. Previous studies showed improvement of the broadband sound absorption with particular shapes of inclusions. However, different volumes of the inclusions have been considered; therefore, the bulk densities are not the same for comparison. The present study extends the investigations of inclusions in porous materials with same volume (or bulk density) to eliminate the influence by the change of bulk density. The effects of shape will be discussed. Finite element modeling will be used for this study. Total four different shapes: …

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Impacts Of Ventilation Ratio And Vent Balance On Cooling Load And Air Flow Of Naturally Ventilated Attics, Shimin Wang, Zhigang Shen Jan 2012

Impacts Of Ventilation Ratio And Vent Balance On Cooling Load And Air Flow Of Naturally Ventilated Attics, Shimin Wang, Zhigang Shen

Durham School of Architectural Engineering and Construction: Faculty Publications

The impacts of ventilation ratio and vent balance on cooling load and air flow of naturally ventilated attics are studied in this paper using an unsteady computational fluid dynamics (CFD) model. Buoyancy-driven turbulent ventilations in attics of gable-roof residential buildings are simulated for typical summer conditions. Ventilation ratios from 1/400 to 1/25 combined with both balanced and unbalanced vent configurations are investigated. The modeling results show that the air flows in the attics are steady and exhibit a general streamline pattern that is qualitatively insensitive to the variations in ventilation ratio and vent configuration. The predicted temperature fields are characterized …

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The Impact Of Roof Pitch And Ceiling Insulation On Cooling Load Of Naturally-Ventilated Attics, Shimin Wang, Zhigang Shen, Linxia Gu Jan 2012

The Impact Of Roof Pitch And Ceiling Insulation On Cooling Load Of Naturally-Ventilated Attics, Shimin Wang, Zhigang Shen, Linxia Gu

Durham School of Architectural Engineering and Construction: Faculty Publications

A 2D unsteady computational fluid dynamics (CFD) model is employed to simulate buoyancy-driven turbulent ventilation in attics with different pitch values and ceiling insulation levels under summer conditions. The impacts of roof pitch and ceiling insulation on the cooling load of gable-roof residential buildings are investigated based on the simulation of turbulent air flow and natural convection heat transfer in attic spaces with roof pitches from 3/12 to 18/12 combined with ceiling insulation levels from R-1.2 to R-40. The modeling results show that the air flows in the attics are steady and exhibit a general streamline pattern that is qualitatively …

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Development And Evaluation Of A Simplified Modeling Approach For Hydraulic Systems, Yuebin Yu, Vivian Loftness, Daihong Yu, Yan Lu, Volker Hartkopf Jan 2012

Development And Evaluation Of A Simplified Modeling Approach For Hydraulic Systems, Yuebin Yu, Vivian Loftness, Daihong Yu, Yan Lu, Volker Hartkopf

Durham School of Architectural Engineering and Construction: Faculty Publications

This paper presents how a hydraulic system can be properly modeled for hydraulic balancing, knowledge of flow distribution, coupled simulation, and evaluation of control, etc. It focuses on water-based heating and cooling systems, which generally have high energy efficiency in design but could perform poorly in reality due to the undersensing condition and strong thermal-hydraulic coupling. The study introduces the motivation, presents the simplified modeling methodology, and illustrates the model and simulating structure. A preliminary evaluation of the method is conducted with two simple simulations. The proposed “node-branch-state” modeling approach could be easily modified, expanded and integrated into a detailed …

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3-Dimensional Intracortical Neural Interface For The Study Of Epilepsy, Jessin Koshy John Jan 2012

3-Dimensional Intracortical Neural Interface For The Study Of Epilepsy, Jessin Koshy John

Wayne State University Dissertations

Epilepsy is a chronic disease characterized by recurrent, unprovoked seizures, where seizures are described as storms of uncontrollable neuro-electrical activity within the brain. Seizures are therefore identified by observation of electrical spiking observed through electrical contacts (electrodes) placed on the scalp or the cortex above the epileptic regions. Current epilepsy research is identifying several specific molecular markers that appear at specific layers of the epilepsy-affected cortex. However, technology is limited in allowing for live observation of electrical spiking across these layers. The underlying hypothesis of this project is that electrical interictal activity is generated in a layer- and lateral-specific pattern. …

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Implementation Of Multiple-Instance Learning In Drug Activity Prediction, Gang Fu Jan 2012

Implementation Of Multiple-Instance Learning In Drug Activity Prediction, Gang Fu

Electronic Theses and Dissertations

In the context of drug discovery and development, much effort has been exerted to determine which conformers of a given molecule are responsible for the observed biological activity. In this work we aimed to predict bioactive conformers using a variant of supervised learning, named multiple-instance learning. A single molecule, treated as a bag of conformers, is biologically active if and only if at least one of its conformers, treated as an instance, is responsible for the observed bioactivity; and a molecule is inactive if none of its conformers is responsible for the observed bioactivity. The implementation requires instance-based embedding, and …

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Preprocessing Of Biomass Using Mechanical, Chemical And Microbial Techniques, Swetha Mahalaxmi Jan 2012

Preprocessing Of Biomass Using Mechanical, Chemical And Microbial Techniques, Swetha Mahalaxmi

Electronic Theses and Dissertations

Biomass-derived fuels have acquired a lot of attention recently due to increasing emphasis on energy independence, efforts to utilize abundance of green resources and mitigation of greenhouse gas emissions. Grasses, agricultural residues, animal residues and waste, used oils, etc., can be used as starting materials in the production of biofuels. Various preprocessing techniques used in the preprocessing of biomass, such as microbial preprocessing, mechanical preprocessing and chemical pretreatment, are used for enhancing the digestibility of biomass to sugars for ethanol production. In this work, studies were conducted to improve the microbial, chemical and mechanical preprocessing of switch grass by decreasing …

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Admicellar Polymerization To Compatibilize Calcium Carbonate With Oil-Based Drilling Mud, Olugbenga Samuel Ojo Jan 2012

Admicellar Polymerization To Compatibilize Calcium Carbonate With Oil-Based Drilling Mud, Olugbenga Samuel Ojo

Electronic Theses and Dissertations

Weighting agents like calcium carbonate (CC) are added to drilling mud to improve mud properties and performance during oil and gas drilling operations. Oil-based mud (OBM), a more preferred drilling mud, being hydrophobic is particularly non-compatible with hydrophilic CC. This work explored an economically viable admicellar polymerization technique to surface-modify the high energy hydrophilic CC surface to a low energy hydrophobic surface by polymerizing organic styrene monomer within an admicelle of nonionic surfactant Triton X-100 adsorbed on the CC surface. BET N2 particle size analysis, Soxhlet extraction of the coated polymer, Fourier transform infrared-attenuated total reflectance (FTIR-ATR) spectra analysis, and …

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Characterizing The Acoustic Properties Of The Jet Lab At The National Center For Physical Acoustics, Joshua Anderson Lieblong Jan 2012

Characterizing The Acoustic Properties Of The Jet Lab At The National Center For Physical Acoustics, Joshua Anderson Lieblong

Electronic Theses and Dissertations

Aerodynamic noise has been a problem since the first use of the jet engine for military aircraft in World War II. For further uses of the jet engine to be possible, problems due to jet noise must be researched and addressed. Anechoic chambers were proposed as a testing facility for research in aerodynamic noise because of their supposed free-field characteristics. The international standard ISO 3745-1977 was introduced to determine whether the facilities could be considered anechoic, semi-anechoic, or neither. An experiment was designed to determine at what frequencies the National Center for Physical Acoustics' Jet Lab Facility is non-anechoic, semi-anechoic, …

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Effect Of Long Chains On The Threshold Stresses For Flow-Induced Crystallization In Ipp: Shish Kebabs Vs. Sausages, Lucia Fernandez-Ballester, Derek W. Thurman, Weijun Zhou, Julia A. Kornfield Jan 2012

Effect Of Long Chains On The Threshold Stresses For Flow-Induced Crystallization In Ipp: Shish Kebabs Vs. Sausages, Lucia Fernandez-Ballester, Derek W. Thurman, Weijun Zhou, Julia A. Kornfield

Department of Mechanical and Materials Engineering: Faculty Publications

The addition of small concentrations (2 wt % or less) of ultrahigh molecular weight isotactic polypropylene (ML ~ 3500 kg/mol) to a matrix of lower molecular weight chains (MS ~ 186 kg/mol, e.g. ML/MS ~ 20) substantially decreases the critical stress for inducing a highly oriented skin under flow-induced crystallization conditions—significantly more than for blends of ML/MS ~ 5 (Seki et al.)—and promotes the formation of point precursors and oriented “sausage-like” structures not observed for ML/MS ~ 5. These differences correlate with the onset of long chain stretching during shear: the ratio of long chains’ Rouse time to short chains’ …

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Sacrificial Structure Preforms For Thin Part Machining, Scott Smith, Robert Wilhelm, Brian Dutterer, Harish Cherukuri, Gaurav Goel Jan 2012

Sacrificial Structure Preforms For Thin Part Machining, Scott Smith, Robert Wilhelm, Brian Dutterer, Harish Cherukuri, Gaurav Goel

Department of Mechanical and Materials Engineering: Faculty Publications

Thin parts are often difficult to create by machining because they have insufficient static and dynamic stiffness. Accurate thin parts are difficult to achieve due to clamping forces, cutting forces, residual stresses, and chatter. Sacrificial structure preforms support the part during machining, but they are not part of the finished component. Preforms may be created in many ways, including forging, welding, gluing, casting, or additive processes. They can be used in many workpiece materials including metals, polymers, and ceramics. We describe a novel process that uses sacrificial structures to make machining insensitive to the thinness of finished parts.

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Visqol: The Virtual Speech Quality Objective Listener, Andrew Hines, Jan Skoglund, Anil Kokaram, Naomi Harte Jan 2012

Visqol: The Virtual Speech Quality Objective Listener, Andrew Hines, Jan Skoglund, Anil Kokaram, Naomi Harte

Conference papers

A model of human speech quality perception has been developed to provide an objective measure for predicting subjective quality assessments. The Virtual Speech Quality Objective Listener (ViSQOL) model is a signal based full reference metric that uses a spectro-temporal measure of similarity between a reference and a test speech signal. This paper describes the algorithm and compares the results with PESQ for common problems in VoIP: clock drift, associated time warping and jitter. The results indicate that ViSQOL is less prone to underestimation of speech quality in both scenarios than the ITU standard.

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Formalising Human Mental Workload As Non-Montonic Concept For Adaptive And Personalised Web-Design, Luca Longo Jan 2012

Formalising Human Mental Workload As Non-Montonic Concept For Adaptive And Personalised Web-Design, Luca Longo

Books/Book Chapters

Web Design has been evolving with Web-based systems becoming more complex and structured due to the delivery of personalised information adapted to end-users. Although information presented can be useful and well formatted, people have little mental workload available for dealing with unusable systems. Subjective mental workload assessments tools are usually adopted to measure the impact of Web-tasks upon end-users thanks to their ease of use and are aimed at supporting design practices. The Nasa Task Load Index subjective procedure has been taken as a reference technique for measuring mental workload, but it has a background in aircraft cockpits, supervisory and …

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Soil Phosphorus Availability And Buffering Capacity In Eastern South Dakota Assessed Using Quantity-Intensity Relationships And Diffusive Gradients In Thin Films, Rose Eitemiller Jan 2012

Soil Phosphorus Availability And Buffering Capacity In Eastern South Dakota Assessed Using Quantity-Intensity Relationships And Diffusive Gradients In Thin Films, Rose Eitemiller

Electronic Theses and Dissertations

Phosphorus (P) availability is influenced by soil properties and depth, creating challenges for nutrient management across agricultural landscapes. This study evaluated two complementary approaches for quantifying P availability and adsorption dynamics in eastern South Dakota soils: Diffusive Gradients in Thin Films (DGT) and P quantity–intensity (Q–I) relationships. The objectives were to (1) quantify bioavailable P using DGT, (2) compare DGT measurements with established soil test P (STP), (3) evaluate Q–I parameters describing P adsorption characteristics, and (4) assess spatial variability in P availability across eastern South Dakota soils. DGT-measured P increased with STP levels and was strongly correlated with Bray-1, …

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Botnet Detection, Ji Ung Choi Jan 2012

Botnet Detection, Ji Ung Choi

Summer Community of Scholars Posters (RCEU and HCR Combined Programs)

No abstract provided.

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"Lead-Free Solders Are Currently Used In The Electronic Components Industry…", Timothy Mead Jan 2012

"Lead-Free Solders Are Currently Used In The Electronic Components Industry…", Timothy Mead

Summer Community of Scholars Posters (RCEU and HCR Combined Programs)

No abstract provided.

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Securing Access To Lower-Cost Talent Globally: The Dynamics Of Active Embedding And Field Structuration, Stephan Manning, Joerg Sydow, Arnold Windeler Jan 2012

Securing Access To Lower-Cost Talent Globally: The Dynamics Of Active Embedding And Field Structuration, Stephan Manning, Joerg Sydow, Arnold Windeler

Management and Marketing Faculty Publication Series

This article examines how multinational corporations (MNCs) shape institutional conditions in emerging economies to secure access to high-skilled, yet lower-cost science and engineering talent. Based on two in-depth case studies of engineering offshoring projects of German automotive suppliers in Romania and China we analyze how MNCs engage in ‘active embedding’ by aligning local institutional conditions with global offshoring strategies and operational needs. MNCs thereby contribute to the structuration of field relations and practices of sourcing knowledge-intensive work from globally dispersed locations.Our findings stress the importance of institutional processes across geographic boundaries that regulate and get shaped by MNC activities.

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Microscopic And Spectroscopic Analysis Of Wo3 And Ti-Doped Wo3 Thin Films, Young Taek Yun Jan 2012

Microscopic And Spectroscopic Analysis Of Wo3 And Ti-Doped Wo3 Thin Films, Young Taek Yun

Open Access Theses & Dissertations

Tungsten oxide (WO3) has been a subject of high interest for its unique properties, and recently for its importance in different types of industrial applications which ranges from non-emissive displays, optical, microelectronic, catalytic/photocatalytic, humidity, temperature, gas, and biosensor devices. In this study, WO3 and Ti doped thin films were prepared using radio frequency magnetron reactive sputtering at different substrate temperatures ranging from room temperature to 500 ºC in increments of 100 ºC. After forming a hypothesis based on knowledge of established WO3 properties, we attempt in this work to investigate how the doping influences the roughness and the mean grain …

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Investigation Of Carbon Corrosion Resistance Of Cnt Containing Electrode, Diana Larrabee, William A. Rigdon, Eli Mcpherson, Joshua Sightler, Xinyu Huang Jan 2012

Investigation Of Carbon Corrosion Resistance Of Cnt Containing Electrode, Diana Larrabee, William A. Rigdon, Eli Mcpherson, Joshua Sightler, Xinyu Huang

Faculty Publications

Carbon support corrosion is one of the major degradation mechanisms of polymer electrolyte membrane (PEM) fuel cell. Carbon oxidation occurs in PEM electrode and is accelerated at high potential created by adverse operating conditions and improper distribution of reactants and products [1, 2, 3]. Carbon corrosion can lead to the thinning of the electrode layer and severe performance degradation. The detailed mechanisms of carbon support corrosion induced performance loss are still not fully understood; it is believed that the following events contribute to the decay: (1) structural collapse of the porous electrode due to the loss of carbon; (2) carbon …

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Underwater Object Detection And Identification Using Distributed Pressure Sensors, Audrey Maertens Jan 2012

Underwater Object Detection And Identification Using Distributed Pressure Sensors, Audrey Maertens

Link Foundation Ocean Engineering and Instrumentation Fellowship Reports

Underwater vision is usually limited. Object detection and identification is therefore one of the main challenges of underwater navigation. A new sensing modality, specifically developed for underwater environments, would greatly increase the scope of underwater missions. Taking inspiration from the lateral line of fish, I believe that pressure sensing can be a viable alternative to vision in order to detect and identify obstacles. Recent advances in the area of micro-engineering will soon enable to build sensors that match the size and mimic the functions and organization of the lateral line. However, little is known about how the pressure distribution along …

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Tunable Gold Nanostructures With Nanocapsules As Template Reaction Vessels, Balasubramanian Ramjee, Srujana Prayakarao, Sangbum Han, Wei Cao Jan 2012

Tunable Gold Nanostructures With Nanocapsules As Template Reaction Vessels, Balasubramanian Ramjee, Srujana Prayakarao, Sangbum Han, Wei Cao

Chemistry & Biochemistry Faculty Publications

Hollow, polymeric, thiol-ene resorcinarene nanocapsules can act as template reaction vessels for the synthesis of gold nanoshells or spherical aggregates of gold nanoparticles depending on the reaction conditions. The spherical nanoparticle aggregates were evaluated as catalysts in the biphasic reduction of 4-nitrophenol.

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Structural Basis Of Substrate Recognition In Thimet Oligopeptidase And Development Of Nanoparticles For Therapeutic Enzyme Delivery, Jonathan Mark Wagner Jan 2012

Structural Basis Of Substrate Recognition In Thimet Oligopeptidase And Development Of Nanoparticles For Therapeutic Enzyme Delivery, Jonathan Mark Wagner

Theses and Dissertations--Molecular and Cellular Biochemistry

Neuropeptidases are responsible for degradation of signaling peptides in the central nervous system and periphery. Some neuropeptidases have also been shown to play a role as part of the cell’s hydrolytic machinery responsible for breaking down proteins and peptides into amino acids, and these enzymes therefore influence small peptide availability for antigen presentation. A better understanding of how neuropeptidases recognize their substrates could lead to therapeutics that modulate the activity of these important enzymes. Alternatively, re-engineering these enzymes to selectively hydrolyze undesirable peptides could make them attractive as therapeutics themselves. A key question in understanding the activity of these enzymes …

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Developing A Promo Video In Premiere Elements: A Day In Dublin, Jerome Casey Jan 2012

Developing A Promo Video In Premiere Elements: A Day In Dublin, Jerome Casey

Instructional Guides

No abstract provided.

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A Unified Nonlinear Adaptive Approach For The Fault Diagnosis Of Aircraft Engines, Remus C. Avram Jan 2012

A Unified Nonlinear Adaptive Approach For The Fault Diagnosis Of Aircraft Engines, Remus C. Avram

Browse all Theses and Dissertations

In this thesis, a fault detection and isolation (FDI) method is developed for aircraft engines by utilizing nonlinear adaptive estimation techniques. Engine sensor faults, actuator faults and component faults are considered under one unified framework. The fault diagnosis architecture consists of a bank of nonlinear adaptive estimators. One of them is the fault detection estimator used for fault detection, and the remaining ones are fault isolation estimators employed to determine the particular fault type/location after fault detection. Each isolation estimator is designed based on the functional structure of a particular fault type under consideration. The FDI architecture has been integrated …

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Mapping Algorithm For Autonomous Navigation Of Lawn Mower Using Sick Laser, Shashidhar Baichbal Jan 2012

Mapping Algorithm For Autonomous Navigation Of Lawn Mower Using Sick Laser, Shashidhar Baichbal

Browse all Theses and Dissertations

The objective of this thesis is to present a mapping algorithm for autonomous navigation of a lawnmower based on the range and bearing information of a SICK laser. The Simultaneous Localization and Mapping (SLAM) algorithm is a tool that can be used to navigate unmanned vehicle in an unknown environment. The two-dimensional (2D) maps of the obstacles can be obtained if the laser scans the environment in a plane horizontal to the ground. However, the 2D map does not give information of the objects that are placed below the height of the laser. This makes it difficult for the lawn …

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Behavioral Signature-Based Framework For Identifying Unsatisfiable Variable Mappings Between Digital Designs, Vaibhav Uday Tendulkar Jan 2012

Behavioral Signature-Based Framework For Identifying Unsatisfiable Variable Mappings Between Digital Designs, Vaibhav Uday Tendulkar

Browse all Theses and Dissertations

Throughout its design process (from specification to implementation) a digital circuit goes through a variety of structural changes. These changes are introduced primarily due to the use of automated tools in the design process. Checking whether the Boolean functions representing the two designs are equivalent is thus necessary to verify if a design implementation adheres to its specification. Combinational Equivalence Checking (CEC) - a process of determining whether two combinational design functions are equiv-alent, has been one of the most researched Boolean matching problems. The well-known CEC techniques that have been proposed adopt some kind of a formal approach such …

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Key Factors Influencing The Structure And Electrochemical Performances Of Lifepo4 Via Sol-Gel Synthesis, Chuang Guan Jan 2012

Key Factors Influencing The Structure And Electrochemical Performances Of Lifepo4 Via Sol-Gel Synthesis, Chuang Guan

Browse all Theses and Dissertations

Olivine structured LiFePO4 is a promising cathode material for the next generation of lithium ion batteries for its low cost, environmental benign, good cycling performance and safety, etc. However, its intrinsic poor electrical conductivity and diffusion capability of lithium ion greatly hinder its application in the high power recharge battery. In this research, a cost-effective sol-gel method was used to synthesize carbon coated LiFePO4 (LiFePO4/C) materials. The influences of the synthesis parameters, including the species of iron source, lithium content, chelating agents and carbon sources, PH value of the sol, and sintering conditions etc., on the structure and electrochemical properties …

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