Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

2008

Discipline
Institution
Keyword
Publication
Publication Type
File Type

Articles 19981 - 20010 of 20019

Full-Text Articles in Entire DC Network

Design And Optimization Of Abrasive Slurry Feed System, Control Circuit And Jet Drilling Tool For Mining Applications,, Pradeep Nambiath Jan 2008

Design And Optimization Of Abrasive Slurry Feed System, Control Circuit And Jet Drilling Tool For Mining Applications,, Pradeep Nambiath

Doctoral Dissertations

"This dissertation focused on an investigation of small diameter hole drilling using abrasive slurry jet (ASJ) technology. The existing ASJ feed systems were reviewed and found inadequate to satisfy the requirements of an ASJ drill. A novel feed system was designed which improved on existing systems by resolving problems with the inability to perform stop/start operations and ensure precise metering of abrasive feed. This system met standards of consistency and evenness of feed required for machining aircraft component parts for Air Force Research Laboratory (AFRL). Theoretical and experimental analysis of the power of an ASJ stream yielded valuable design information …

Go to article

Formation And Removal Of Pesticides And Pesticide Transformation Products During Water Treatment, Evelyn F. Chamberlain Jan 2008

Formation And Removal Of Pesticides And Pesticide Transformation Products During Water Treatment, Evelyn F. Chamberlain

Doctoral Dissertations

"A comprehensive suite of over 60 pesticides (herbicides, insecticides, and fungicides) representing a variety of classes at environmentally relevant concentrations (low µg/L) were screened for reactivity under typical drinking water conditions and dosages. The most common oxidants/transformation agents in water treatment systems were examined for reactivity including free and combined chlorine, chlorine dioxide, permanganate, ozone, hydrogen peroxide, ultraviolet radiation, and high pH (alkaline hydrolysis). Due to the broad nature of the study, pesticide compounds were analyzed as multiple mixes broken into two groups based on analytical methods, those analyzed by GC/ECD and those by LC/MS. Combinations of reactive disinfectant/oxidant and …

Go to article

Elicited Imitation As An Oral Proficiency Measure With Asr Scoring, Deryle W. Lonsdale, C. Ray Graham, Casey Kennington, Aaron W. Johnson, Jeremiah Lane Mcghee Jan 2008

Elicited Imitation As An Oral Proficiency Measure With Asr Scoring, Deryle W. Lonsdale, C. Ray Graham, Casey Kennington, Aaron W. Johnson, Jeremiah Lane Mcghee

Faculty Publications

This paper discusses development and evaluation of a practical, valid and reliable instrument for evaluating the spoken language abilities of second-language (L2) learners of English. First we sketch the theory and history behind elicited imitation (EI) tests and the renewed interest in them. Then we present how we developed a new test based on various language resources, and administered it to a few hundred students of varying levels. The students were also scored using standard evaluation techniques, and the EI results were compared to more traditionally derived scores. We also sketch how we developed a new integrated tool that allows …

Go to article

Assessing Clinical Trial Eligibility With Logic Expression Queries, Deryle W. Lonsdale, C. Tutison, Craig G. Parker, David W. Embley Jan 2008

Assessing Clinical Trial Eligibility With Logic Expression Queries, Deryle W. Lonsdale, C. Tutison, Craig G. Parker, David W. Embley

Faculty Publications

This paper introduces a system that processes clinical trials using a combination of natural language processing and database techniques. We process web-based clinical trial recruitment pages to extract semantic information reflecting eligibility criteria for potential participants. From this information we then formulate a query that can match criteria against medical data in patient records. The resulting system reflects a tight coupling of web-based information extraction, natural language processing, medical informatic approaches to clinical knowledge representation, and large-scale database technologies. We present an evaluation of the system and future directions for further system development.

Go to article

Energy Efficient Correlated Data Aggregation For Wireless Sensor Networks, Seung Jong Park, Raghupathy Sivakumar Jan 2008

Energy Efficient Correlated Data Aggregation For Wireless Sensor Networks, Seung Jong Park, Raghupathy Sivakumar

Computer Science Faculty Research & Creative Works

Data aggregations from Sensors to a sink in wireless sensor networks (WSNs) are typically characterized by correlation along the spatial, semantic, and temporal dimensions. Exploiting such correlation when performing data aggregation can result in considerable improvements in the bandwidth and energy performance of WSNs. For the sensors-to-sink data delivery, we first explore two theoretical solutions: the shortest path tree (SPT) and the minimum spanning tree (MST) approaches. To approximate the optimal solution (MST) in case of perfect correlation among data, we propose a new aggregation which combines the minimum dominating set (MDS) with the shortest path tree (SPT) in order …

Go to article

Polyaniline Nanofiber-Based Gas Sensors, Zhe-Fei Li, Frank D. Blum, Massimo F. Bertino, Chang-Soo Kim Jan 2008

Polyaniline Nanofiber-Based Gas Sensors, Zhe-Fei Li, Frank D. Blum, Massimo F. Bertino, Chang-Soo Kim

Chemistry Faculty Research & Creative Works

There has been recent interest in conducting polymers that have very promising chemical and electrical applications. Some of these polymers have shown great potential for use in sensors.1 Polyaniline is one particular example of a prospective material. In our laboratory, we have studied the synthesis of polyaniline nanofibers. We have carried out one-pot syntheses to obtain polyaniline nanofibers in aqueous solutions where the polymerization was influenced by γ-radiation2 or UV-radiation.3 This polymer can also be patterned with an appropriate photo mask. In our present report, polyaniline nanofiber thin film sensors have been fabricated in one step by employing UV-irradiation and …

Go to article

Simulation Of The Evolution Of The Nanostructure Of Crosslinked Silica-Aerogels Under Compression, Hongbing Lu, Boshen Fu, Nitin Daphalapurkar, Jay Hanan, Nicholas Leventis, Chariklia Sotiriou-Leventis Jan 2008

Simulation Of The Evolution Of The Nanostructure Of Crosslinked Silica-Aerogels Under Compression, Hongbing Lu, Boshen Fu, Nitin Daphalapurkar, Jay Hanan, Nicholas Leventis, Chariklia Sotiriou-Leventis

Chemistry Faculty Research & Creative Works

Silica-aerogels are ultra-low-density assemblies of silica nanoparticles, and possess superior acoustic, specific energy absorption and thermal insulation properties. A new class of aerogels encapsulated with polymer is classified as crosslinked silica-aerogels. Manufacturing of such crosslinked silica-aerogel structures, depending on the type and shape of the nanoparticles, the polymer cross-linker and the chemistry in use, yields structures with vastly different morphologies and a wide range of mechanical behavior. With this, it has become necessary to understand the nanostructure / macroscopic properties relationship. Modeling of the aerogel material properties from mesoscale and up approach is needed, which is not considered by the …

Go to article

Thermal Analysis Of Adsorbed Poly(Vinyl Acetate) On Silica, Boonta Hetayothin, Frank D. Blum Jan 2008

Thermal Analysis Of Adsorbed Poly(Vinyl Acetate) On Silica, Boonta Hetayothin, Frank D. Blum

Chemistry Faculty Research & Creative Works

The physical properties of polymers at interfaces can be quite different from those in bulk due to the interaction between the absorbed polymer and the surface. This phenomenon can be probed through the dynamic behavior of the polymer chains at the interface which can be experimentally probed by techniques such as nuclear magnetic resonance spectroscopy (NMR),1 viscoelasticity, and calorimetry. At the polymer-air interface, polymer chains have more flexibility than those at the polymer-substrate interface. On the other hand, at the silica-polymer interface, where chains are more restricted on the surface, a higher glass transition temperature (Tg) results as compared with …

Go to article

Dynamics Of Pipa-D₇ On Silica Surface, Piyawan Krisanangkura, Frank D. Blum Jan 2008

Dynamics Of Pipa-D₇ On Silica Surface, Piyawan Krisanangkura, Frank D. Blum

Chemistry Faculty Research & Creative Works

Molecular motion of polymer chains is an important determinant in understanding the physical properties of polymeric materials. Glass transition temperature (Tg) is a physical property of polymers, which is of primary interest. The study of the dynamics of polymer segments assists in understanding the dependence of Tg on polymer structure.1 For decades, studies have addressed the molecular motion in various polymers. Some of them have probed the dynamics of polymer backbones.2,3 the properties of a polymer at an interface may change because of the type of polymer, the substrate, or other variables. The side chain of a polymer can also …

Go to article

Real-Time Implementation Of A Statcom On A Wind Farm Equipped With Doubly Fed Induction Generators, Wei Qiao, Ganesh K. Venayagamoorthy, Ronald G. Harley Jan 2008

Real-Time Implementation Of A Statcom On A Wind Farm Equipped With Doubly Fed Induction Generators, Wei Qiao, Ganesh K. Venayagamoorthy, Ronald G. Harley

Electrical and Computer Engineering Faculty Research & Creative Works

Voltage stability is a key issue to achieve the uninterrupted operation of wind farms equipped with doubly fed induction generators (DFIGs) during grid faults. This paper investigates the application of a static synchronous compensator (STATCOM) to assist with the uninterrupted operation of a wind turbine driving a DFIG, which is connected to a power network, during grid faults. The control schemes of the DFIG rotor- and grid-side converters and the STATCOM are suitably designed and coordinated. The system is implemented in real-time on a real time digital simulator. Results show that the STATCOM improves the transient voltage stability and therefore …

Go to article

Dual-Polarized Near-Field Microwave Reflectometer For Noninvasive Inspection Of Carbon Fiber Reinforced Polymer-Strengthened Structures, Sergey Kharkovsky, Adam C. Ryley, Vivian Stephen, R. Zoughi Jan 2008

Dual-Polarized Near-Field Microwave Reflectometer For Noninvasive Inspection Of Carbon Fiber Reinforced Polymer-Strengthened Structures, Sergey Kharkovsky, Adam C. Ryley, Vivian Stephen, R. Zoughi

Electrical and Computer Engineering Faculty Research & Creative Works

Carbon fiber reinforced polymer (CFRP) composites are increasingly being used to strengthen various components of civil, aerospace, and automotive infrastructures. Subsequent to the application of CFRP, evaluation of the structural integrity of the strengthened members becomes a critical issue. Microwave noninvasive inspection techniques have been successfully used for this purpose. To this end, a novel near-field microwave inspection system that employs a dual-polarized reflectometer for detecting defects, such as disbonds between CFRP laminates and strengthened structures, was developed. It is shown that this system is capable of automatic removal of the influence of undesired standoff distance (or surface roughness) variations. …

Go to article

Improved Bdfe Using A Priori Information For Turbo Equalization, Jingxian Wu, Sang-Yick Leong, Kah-Ping Lee, Chengshan Xiao, Jan C. Olivier Jan 2008

Improved Bdfe Using A Priori Information For Turbo Equalization, Jingxian Wu, Sang-Yick Leong, Kah-Ping Lee, Chengshan Xiao, Jan C. Olivier

Electrical and Computer Engineering Faculty Research & Creative Works

Turbo equalization improves communication system performance by iteratively exchanging information between soft-input soft-output (SISO) equalizer and SISO channel decoder. The trellis-based maximum a posteriori probability (MAP) algorithm serves as the optimum SISO equalizer for turbo equalization. However, MAP algorithm is unsuitable for systems with large modulation constellation size and severe inter-symbol interference (ISI) due to its prohibitively high computational complexity. In this paper, an improved SISO block decision feedback equalizer (BDFE) is proposed for low complexity turbo equalization. Unlike other sub-optimum equalizers which perform symbol by symbol detection, the proposed equalizer generates the soft output for each data bit by …

Go to article

Employing Adaptive Structuring As A Cognitive Decision Aid In High Reliability Organizations, Karlene H. Roberts, Kuo Frank Yu, Vinit M. Desai, Peter Madsen Jan 2008

Employing Adaptive Structuring As A Cognitive Decision Aid In High Reliability Organizations, Karlene H. Roberts, Kuo Frank Yu, Vinit M. Desai, Peter Madsen

Faculty Publications

The article begins by discussing processes contributing to high and low reliability decision making. It then discusses three cases, covering similar processes used in the three situations and notes what managers can take from this. Finally, the article argues for research that does not concentrate on a single organization but examines interactions among geographically distributed units addressing the same problem.

Go to article

Ict Perceptions And Meanings: Implications For Knowledge Transfer, Anne P. Massey, Taylor M. Wells Jan 2008

Ict Perceptions And Meanings: Implications For Knowledge Transfer, Anne P. Massey, Taylor M. Wells

Faculty Publications

Driven by global competition and economic pressures, organizations are increasingly interested in transferring and leveraging local expertise at the global level. While many of the challenges of knowledge transfer (KT) have been discussed in the literature (e.g., incentives, cognitive limitations), the challenge of KT in distributed, or “virtual”, settings and the role of information and communication technologies (ICTs) have received limited attention. While any given ICT may be described in terms of one’s perceptual awareness of its capabilities (e.g., richness, interactivity), it may also be described relative to the meanings an individual attaches to it, i.e., the idea of it …

Go to article

An Overview And Tutorial Of The Repertory Grid Technique In Information Systems Research, Aaron Mosiah Curtis, Taylor Michael Wells, Paul Benjamin Lowry, Trevor Higbee Jan 2008

An Overview And Tutorial Of The Repertory Grid Technique In Information Systems Research, Aaron Mosiah Curtis, Taylor Michael Wells, Paul Benjamin Lowry, Trevor Higbee

Faculty Publications

Interest in the repertory grid technique has been growing in the IS field. This article seeks to inform the reader on the proper use and application of the technique in IS research. The methodology has unique advantages that make it suitable for many research settings. In this tutorial, we describe the technique, its theoretical underpinnings, and how it may be used by IS researchers. We conclude by detailing many IS research opportunities that exist in respect to the repertory grid technique.

Go to article

Energy Harvesting Using Piezoelectric Materials And High Voltage Scavenging Circuitry, Shahab Mehraeen, Jagannathan Sarangapani, Keith Corzine Jan 2008

Energy Harvesting Using Piezoelectric Materials And High Voltage Scavenging Circuitry, Shahab Mehraeen, Jagannathan Sarangapani, Keith Corzine

Electrical and Computer Engineering Faculty Research & Creative Works

Piezoelectric transducers are increasingly being used to harvest energy from environmental vibrations in order to power remote sensors or to charge batteries that power the sensors. In this paper, two modifications have been analyzed and tested to increase the harvested electrical power from a vibrating piezoelectric material. First, the voltage inversion method, which has recently been used in piezoelectricbased energy harvesting, and that shapes the voltage to be in phase with current in order to increase the harvested power is reviewed. By injecting additional current, a new voltage inversion scheme, referred as voltage compensation scheme, is introduced. This new scheme …

Go to article

Multiple-Input Multiple-Output Rayleigh Flat Fading Outage Capacity Using Channel Estimation, Chris G. Potter, Kurt Louis Kosbar, Adam Panagos Jan 2008

Multiple-Input Multiple-Output Rayleigh Flat Fading Outage Capacity Using Channel Estimation, Chris G. Potter, Kurt Louis Kosbar, Adam Panagos

Electrical and Computer Engineering Faculty Research & Creative Works

Upper and lower bounds on the outage capacity for a multiple-input multiple-output (MIMO) Rayleigh flat fading wireless baseband communication environment are derived for the case when the channel is completely unknown at the transmitter and the receiver has access to channel state information (CSI) via pilot estimation. The bounds show that the channel estimation error significantly impacts the outage capacity. A change in the outage probability is also shown to have a larger impact on the outage capacity when the channel estimation error is small. To get an idea of how these bounds are affected by a temporally correlated channel, …

Go to article

Evolution Of Surface Deposits On A High-Pressure Turbine Blade—Part I: Physical Characteristics, James Edward Wammack, Jared M. Crosby, Daniel Fletcher, Jeffrey P. Bons, Thomas H. Fletcher Jan 2008

Evolution Of Surface Deposits On A High-Pressure Turbine Blade—Part I: Physical Characteristics, James Edward Wammack, Jared M. Crosby, Daniel Fletcher, Jeffrey P. Bons, Thomas H. Fletcher

Faculty Publications

Turbine blade coupons with three different surface treatments were exposed to deposition conditions in an accelerated deposition facility. The facility simulates the flow conditions at the inlet to a first stage high-pressure turbine (T=1150 C, M=0.31). The combustor exit flow is seeded with dust particulate that would typically be ingested by a large utility power plant. The three coupon surface treatments included: (1) bare polished metal; (2) polished thermal barrier coating with bondcoat; and (3) unpolished oxidation resistant bondcoat. Each coupon was subjected to four successive 2 h deposition tests. The particulate loading was scaled to simulate 0.02 parts per …

Go to article

Effects Of Temperature And Particle Size On Deposition In Land Based Turbines, Jared M. Crosby, Scott Lewis, Jeffrey P. Bons, Weiguo Ai, Thomas H. Fletcher Jan 2008

Effects Of Temperature And Particle Size On Deposition In Land Based Turbines, Jared M. Crosby, Scott Lewis, Jeffrey P. Bons, Weiguo Ai, Thomas H. Fletcher

Faculty Publications

Four series of tests were performed in an accelerated deposition test facility to study the independent effects of particle size, gas temperature, and metal temperature on ash deposits from two candidate power turbine synfuels (coal and petcoke). The facility matches the gas temperature and velocity of modern first stage high pressure turbine vanes while accelerating the deposition process. Particle size was found to have a significant effect on capture efficiency with larger particles causing significant thermal barrier coating (TBC) spallation during a 4 h accelerated test. In the second series of tests, particle deposition rate was found to decrease with …

Go to article

Evolution Of Surface Deposits On A High-Pressure Turbine Blade—Part Ii: Convective Heat Transfer, Jeffrey P. Bons, James Edward Wammack, Jared M. Crosby, Daniel Fletcher, Thomas H. Fletcher Jan 2008

Evolution Of Surface Deposits On A High-Pressure Turbine Blade—Part Ii: Convective Heat Transfer, Jeffrey P. Bons, James Edward Wammack, Jared M. Crosby, Daniel Fletcher, Thomas H. Fletcher

Faculty Publications

A thermal barrier coating (TBC)-coated turbine blade coupon was exposed to successive deposition in an accelerated deposition facility simulating flow conditions at the inlet to a first stage high pressure turbine (T=1150 C, M=0.31). The combustor exit flow was seeded with dust particulate that would typically be ingested by a large utility power plant. The turbine coupon was subjected to four successive 2 h deposition tests. The particulate loading was scaled to simulate 0.02 parts per million weight (ppmw) of particulate over 3 months of continuous gas turbine operation for each 2 h laboratory simulation (for a cumulative 1 year …

Go to article

Characteristics Of Black Liquor Sprays From Gas-Assisted Atomizers In Hightemperature Environments, Andrew J. Mackrory, Dale Tree, Larry L. Baxter Jan 2008

Characteristics Of Black Liquor Sprays From Gas-Assisted Atomizers In Hightemperature Environments, Andrew J. Mackrory, Dale Tree, Larry L. Baxter

Faculty Publications

Black liquor droplets in an entrained-flow gasifier that are too large or too small can cause problems in the chemical recovery process. It is therefore important in gasifier design to understand the nature of the atomized-gas spray. We used high-speed imaging to study black liquor sprays in cold and hot environments. Significant conclusions are that: 1. the droplet size distribution width is linked to the mean droplet size as for other sprays in the literature, necessitating a gasifier design that is tolerant of the distribution width associated with the target droplet size; 2. the shape of black liquor droplets is …

Go to article

The Effect Of Free Chlorine And Monochloramine On Lead In Drinking Water And Epitaxial Electrodeposition Of Tin Sulfide, Sansanee Boonsalee Jan 2008

The Effect Of Free Chlorine And Monochloramine On Lead In Drinking Water And Epitaxial Electrodeposition Of Tin Sulfide, Sansanee Boonsalee

Doctoral Dissertations

"Electrochemical deposition is utilized in various electronic and photovoltaic applications and in the protective coating industries. This dissertation primarily addresses the environmental aspects of electrochemical deposition. In the first part of this study, Pb dissolution in drinking water was investigated in the presence of two disinfectants: free chlorine (in the form of HOCI/OCr) and monochloramine (NH₂Cl). In the second part of this study, epitaxial SnS nanodisks were electrodeposited onto a Au(100) substrate. Water utility systems use either free chlorine or monochloramine in their disinfection program. Whereas free chlorine reacts with natural organic matter in the water to produce halogenated organic …

Go to article

Uncertainty Analysis And Sensitivity Analysis For Multidisciplinary Systems Design, Jia Guo Jan 2008

Uncertainty Analysis And Sensitivity Analysis For Multidisciplinary Systems Design, Jia Guo

Doctoral Dissertations

"The objective of this research is to quantify the impact of both aleatory and epistemic uncertainties on performances of multidisciplinary systems. Aleatory uncertainty comes from the inherent uncertain nature and epistemic uncertainty comes from the lack of knowledge. Although intensive research has been conducted on aleatory uncertainty, few studies on epistemic uncertainty have been reported. In this work, the two types of uncertainty are analyzed. Aleatory uncertainty is modeled by probability distributions while epistemic uncertainty is modeled by intervals. Probabilistic analysis (PA) and interval analysis (IA) are integrated to capture the effect of the two types of uncertainty. The First …

Go to article

Characterization And Synthesis Of Nanoscale Materials, Jinfeng Wang Jan 2008

Characterization And Synthesis Of Nanoscale Materials, Jinfeng Wang

Doctoral Dissertations

"This dissertation focuses on the systematic study of techniques for characterization and synthesis of nanoscale materials. We have achieved several goals. Firstly, high number density uniform zinc oxide nanostructure growth has been achieved using thermal evaporation, through control of experimental parameters that include source material temperature, substrate temperature, substrate material, gas flow rate, and choice of catalyst. Aligned zinc oxide nanowires, randomly oriented zinc oxide nanowires, zinc oxide container-shaped structures, and zinc oxide nanobelts have been synthesized with high yield. Secondly, using a one parameter family of lattice fringe geometry curves, we show how to examine the epitaxial relationship between …

Go to article

Design And Evaluation Of A Virtual Reality Training System For New Underground Rockbolters, David Nutakor Jan 2008

Design And Evaluation Of A Virtual Reality Training System For New Underground Rockbolters, David Nutakor

Doctoral Dissertations

"The need for development of better training techniques for underground rock bolters is signified by the fact that a large number of experienced miners (Baby Boomers) will be retiring soon. This means that there will be very little interface time between the new miners and the experienced miners, which could have been used for training the new inexperienced miners. A new generation of workers (Nexters), who have grown up with computers and video games will replace the Baby Boomers, and the most efficient way to introduce them to the safety and health issues of the mining industry is to use …

Go to article

Energy Efficient Clustering And Secure Data Aggregation In Wireless Sensor Networks, Julia Albath Jan 2008

Energy Efficient Clustering And Secure Data Aggregation In Wireless Sensor Networks, Julia Albath

Doctoral Dissertations

"Communication consumes the majority of a wireless sensor network's limited energy. There are several ways to reduce the communication cost. Two approaches used in this work are clustering and in-network aggregation. The choice of a cluster head within each cluster is important because cluster heads use additional energy for their responsibilities and that burden needs to be carefully distributed. We introduce the energy constrained minimum dominating set (ECDS) to model the problem of optimally choosing cluster heads in the presence of energy constraints. We show its applicability to sensor networks and give an approximation algorithm of O(log n) for solving …

Go to article

Integrated Process Planning For A Hybrid Manufacturing System, Lan Ren Jan 2008

Integrated Process Planning For A Hybrid Manufacturing System, Lan Ren

Doctoral Dissertations

"A hybrid manufacturing system integrated CNC machining and laser-aided layered deposition and achieves the benefits of both processes. In this dissertation, an integrated process planning framework which aims to automate the hybrid manufacturing process is investigated. Critical components of the process planning, including 3D spatial decomposition of the CAD model, improvement of the toolpath generation pattern, repairing strategies using a hybrid manufacturing system, etc., are discussed"--Abstract, page iv.

Go to article

System And Ic Level Analysis Of Electrostatic Discharge (Esd) And Electrical Fast Transient (Eft) Immunity And Associated Coupling Mechanisms, Jayong Koo Jan 2008

System And Ic Level Analysis Of Electrostatic Discharge (Esd) And Electrical Fast Transient (Eft) Immunity And Associated Coupling Mechanisms, Jayong Koo

Doctoral Dissertations

"The exposure of electronic circuits to lightning, electrostatic discharge (ESD), electrical fast transients (EFT) or sine wave signals can reveal RF immunity problems. Typical problems include temporary malfunctions or permanent damage of integrated circuits (ICs). In an effort to reproduce those disturbances, a series of electromagnetic compatibility standards has been developed. However, a complete understanding of the root cause of the immunity problems has yet to be established. This dissertation discusses immunity problems in three papers, starting at the system level, via the coupling path into the IC"--Abstract, page iv.

Go to article

Friction Stir Channeling: An Innovative Technique For Heat Exchanger Manufacturing, Nagarajan Balasubramanian Jan 2008

Friction Stir Channeling: An Innovative Technique For Heat Exchanger Manufacturing, Nagarajan Balasubramanian

Doctoral Dissertations

"Friction stir processing (FSP) is an emerging processing technique based on the principles of friction stir welding (FSW), which is a relatively new solid-state metal joining process developed by The Welding Institute, UK. Some of the unique features of FSW such as the low amount of heat generated, extensive plastic deformation and controlled flow of material is being exploited to develop new material modification and manufacturing processes. Friction stir channeling (FSC) is one such adaptation of FSP that can produce continuous and stable internal channels for application in heat exchanging equipment. Friction stir channeling produces these channels if the defect …

Go to article

Addressing Nonlinear Combustion Instabilities In Highly Dilute Spark Ignition Engine Operation, Brian C. Kaul Jan 2008

Addressing Nonlinear Combustion Instabilities In Highly Dilute Spark Ignition Engine Operation, Brian C. Kaul

Doctoral Dissertations

"Dilute operation is a promising approach for increasing spark-ignition engine efficiency, in the form of either lean burn (air dilution) or EGR (inert dilution). High levels of charge dilution, however, lead to cyclic variability that is largely deterministic in nature. The determinism and nonlinear nature of the system indicate that it should be possible to reduce the cycle-to-cycle variations by implementing an electronic controller. Several needs arise when considering the development of such a controller. Three topics of interest are covered herein. First, a method of analysis for nonlinear dynamical systems is applied to engine data in order to estimate …

Go to article

First Prev Next Last