Engineering Commons^™

Transmission Of Electromagnetic Power Through A Biological Medium, Ripan Das

LSU Master's Theses

Primary goal of this work is to study transmission of EM power through a multilayered biological medium. For a particular case study, EM power transmission from an external transmitter to a coupled receiver implanted inside a biological medium simulating a human body is studied to find solutions for factors such as optimum transmission frequency and excitation current. Different aspects of interaction of EM waves with biological bodies and tissues are discussed. Two major factors that may affect transmission of EM power through a biological body are absorption and reflection of EM waves. A simulation in which exact Maxwell's equations are …

Laboratory Evaluation Of In-Situ Tests As Potential Quality Control/Quality Assurance Tools, Ekrem Seyman

LSU Master's Theses

There are new in-situ test devices such as the Geogauge, Light Falling Weight Deflectometer (LFWD) and Dynamic Cone Penetrometer (DCP). Unlike the nuclear density gauge, the new methods provide measurements based on the engineering properties (strength/stiffness) of soil instead of physical properties like field density and moisture content. However the geogauge, LFWD and the DCP are not yet proven to be reliable and the correlations of these tests with standard tests are limited. An extensive laboratory investigation was carried out to evaluate the Geogauge, LFWD and DCP as potential tests to measure in-situ stiffness of highway materials and embankments. In …

Wind Loads On Multiple Cylinders Arranged In Tandem With Effects Of Turbulence And Surface Roughness, Xianzhi Liu

LSU Master's Theses

The goal of this study is to investigate the characteristics of mean drag and lift forces for a series of cylinders arranged in tandem with varying flow turbulence and surface roughness. This goal was fulfilled by building a wind tunnel test section capable of generating both smooth flow and turbulent flow, and by adopting cylinder models with certain types of surface roughness as well as the smooth surface. In both smooth flow and grid-turbulence flow conditions, single cylinders as well as multiple cylinders were tested. The tested Reynolds number ranged from 2.7×104 to 8.6×104. For multiple-cylinder tests, a majority of …

Computational Model For Heat Transfer In The Human Eye Using The Finite Element Method, Umit Cicekli

LSU Master's Theses

In this work a finite element model for the human eye presented. Thermal analysis was done in order to capture the temperature variation in the human eye. The model was created using advance finite element program ABAQUS. In the model each of the eye's component (cornea, sclera, lens, iris, aqueous and vitreous humor) has own material property. Specific boundary conditions were used for the model. The model incorporates the interaction between eyes components. The Comparisons were done with the available experimental results. The results show that there is a temperature variation in the human eye components with the increasing the …

Numerical Solution Of Ocular Fluid Dynamics, Satish Kumar

LSU Master's Theses

Numerical calculations of the aqueous humor dynamics in the anterior chamber of both the rabbit and the human eye are presented to delineate the basic flow and transport mechanisms. The calculations are based on a geometrical model of the eye, which represents the Trabecular mesh (TM) as a multi-layered porous zone of specified pore sizes and void fraction. Buoyancy is observed to be the dominant driving mechanism for the convective motion in both orientations (horizontal and vertical) of the eye. Reducing the TM pore size does not appear to have a significant influence on the intra-ocular pressure (IOP) until the …

Iddq Testing Of A Cmos 10-Bit Charge Scaling Digital-To-Analog Converter, Srinivas Rao Aluri

LSU Master's Theses

This work presents an effective built-in current sensor (BICS), which has a very small impact on the performance of the circuit under test (CUT). The proposed BICS works in two-modes the normal mode and the test mode. In the normal mode the BICS is isolated from the CUT due to which there is no performance degradation of the CUT. In the testing mode, our BICS detects the abnormal current caused by permanent manufacturing defects. Further more our BICS can also distinguish the type of defect induced (Gate-source short, source-drain short and drain-gate short). Our BICS requires neither an external voltage …

Investigation Of Qualitative Methods For Diagnosis Of Poor Bit Performance Using Surface Drilling Parameters, Arash Aghassi

LSU Master's Theses

Bit performance in deep shale when using water-based mud is typically poor. This study is part of a larger research project to improve that performance entitled "Automated Rig Controls for Improved Drilling Costs." The objective of the project is diagnosis of changes in drill bit performance to provide a logical basis for automating draw works control, maximizing bit performance, and reducing drilling costs. The specific goal of this study is a means to diagnose bit performance, specifically to identify bit balling and lithology changes, using real-time drilling data. The research began by identifying symptoms relating to specific causes of bit …

Remote Power Delivery And Signal Amplification For Mems Applications, Sunitha Kopparthi

LSU Master's Theses

Device such as remotely located sensors and bio-implanted devices such as gastric pacer require power for operation. The most commonly used energy source for such devices is a battery cell included in the receiver capsule. Wires can also be used with an external power source but in some applications have serious limitations. This work examines a wireless power transmitter and receiver system to provide power to a remotely located microsystem. Inductive power coupling is the method of choice. For gastric pacer application, external transmitter coil can be worn around the waist as a belt and the receiver coil can be …

Blind Fault Detection Using Spectral Signatures, Pallavi Chethan

LSU Master's Theses

This work studies a blind fault detection method, which only analyses a system's output signal for any change in the characteristics from pre-fault to post-fault to identify the occurrence of faults. In our case the fault considered to develop the procedure is change in time constant of an aircraft's aileron-actuator system and its simplified version - a position servo system. The method is studied as an alternative to conventional fault detection and identification methods. The output signal is passed through a filter bank to enhance the effect of a fault. The Short time Fourier transform is performed on the enhanced …

Tensile Strength And Bonding Characteristics Of Self-Compacting Concrete, Cristian Druta

LSU Master's Theses

Self-compacting concrete, also referred to as self-consolidating concrete, is able to flow and consolidate under its own weight and is deaerated almost completely while flowing in the formwork. It is cohesive enough to fill the spaces of almost any size and shape without segregation or bleeding. This makes SCC particularly useful wherever placing is difficult, such as in heavily-reinforced concrete members or in complicated workforms. The objectives of this research were to compare the Splitting Tensile Strength and Compressive Strength values of self-compacting and normal concrete specimens and to examine the bonding between the coarse aggregate and the cement paste …

The Transcendental Eigenvalue Problem And Its Application In System Identification, Kumar Vikram Singh

LSU Doctoral Dissertations

An accurate mathematical model is needed to solve direct and inverse problems related to engineering analysis and design. Inverse problems of identifying the physical parameters of a non-uniform continuous system based on the spectral data are still unsolved. Traditional methods, for the system identification purpose, describe the continuous structure by a certain discrete model. In dynamic analysis, finite element or finite difference approximation methods are frequently used and they lead to an algebraic eigenvalue problem. The characteristic equation associated with the algebraic eigenvalue problem is a polynomial. Whereas, the spectral characteristic of a continuous system is represented by certain transcendental …

Nebraska Summary 442: Fendt 716 Vario Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA

The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data.

EXPLANATION OF THE TEST PROCEDURES

Purpose

The purpose of …

Test 2088: Case Ih Mxm130 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Phase Balancing And Harmonic Mitigation For Large Electrical Loads, Hugh O'Kelly

Masters

This thesis describes the development and implementation of new solutions to the power quality problems associated with large unbalanced and non-linear loads. The thesis was undertaken in the context of the fine glass industry and the development work was carried out at three production plants belonging to a world leading fine glass producer. In the process of fine glass production, furnaces are used to melt the silica mix into a liquid of treacle consistency. These furnaces are generally enclosed, except for several small orifices about 50 mm in diameter, which are located around their perimeter. Through these openings, glass blowers …

Scientific And Engineering Studies Of Systems, Structures, And Components Important To Safety For A Potential Repository At Yucca Mountain, Nevada, Ian Buckle, E. Manos Maragakis

Publications (YM)

TASK 26: Upgrade of Earthquake Simulation Facilities in the Large-Scale Structures Laboratory at University of Nevada Reno The objective of this Task was to purchase, install and commission the equipment necessary to upgrade two existing shake tables in the Structures Laboratory at UNR, from uniaxial to biaxial motion. It was recognized that a parallel effort, funded by NSF and HUD, to add a third biaxial table with identical properties to the upgraded existing tables, would be undertaken at the same time.

Identity Management, Duncan A. Buell, Ravi Sandhu

Faculty Publications

No abstract provided.

The Sentient Web, Michael N. Huhns

Faculty Publications

In a startling revelation, a team of university scientists has reported that a network of computers has become conscious and sentient, and is beginning to assume control of online information system. In spite of the ominous tone typically chosen for dramatic effect, a sentient Web would be more helpful and much easier for people to use. An agent is an active, persistent software component that perceives, reasons, and acts, and whose actions include communication. Agents inherently take intentional actions based on sensory information and memories of past actions. All agents have necessary communication ability, but they do not necessarily possess …

The Zen Of The Web, Jeff Heflin, Michael N. Huhns

Faculty Publications

No abstract provided.

Commitments Among Agents, Ashok U. Mallya, Michael N. Huhns

Faculty Publications

Commitments are a powerful representation for modeling multiagent interactions. Previous approaches have considered the semantics of commitments and how to check compliance with them. However, these approaches do not capture some of the subtleties that arise in real-life applications such as e-commerce, in which contracts and institutions have implicit temporal references. In this column, we describe a rich representation for the temporal content of commitments that lets us capture realistic contracts and avoid ambiguities. Consequently, this approach lets us reason about whether, and at what point, a commitment is satisfied or breached, and whether it is or ever becomes unenforceable.

Being And Acting Rational, Michael N. Huhns

Faculty Publications

Rationality alone is insufficient to specify agent design. Using economic theory, we can program agents to behave in ways that maximize their utility while responding to environmental changes. However, economic models for agents, although general in principle, are typically limited in practice because the value functions that are tractable essentially reduce an agent to acting selfishly. Building a stable social system from a collection of agents motivated by self-serving interests is difficult. Finally, understanding rationality and knowledge requires interdisciplinary results from artificial intelligence, distributed.

Massive Deliberation, William H. Turkett Jr., John R. Rose, Michael N. Huhns

Faculty Publications

Agents are proliferating on the Web, making it conceivable that their collective reasoning ability might someday be harnessed for robust decision-making. The hope is that massive deliberation power can soon help solve problems that require knowledge, reasoning, and intelligence. Until recently, working individually or in small groups, agents across the Web could barely communicate and could only reason under conditions of severely bounded rationality. Projects such as Agentcities showed that widespread heterogeneous agents could collaborate on specific predefined tasks and provide diverse agent-based services. When the tasks are dynamic, of long duration, and ill defined, however, success requires planning that …

Interpolation Techniques For Overset Grids, Paul S. Sherman, Nathan B. Edgar

Journal of the Arkansas Academy of Science

The use of finite difference schemes in computational aeroacoustics requires the use of structured grids incomputational space. Complex geometries in the physical space can be modeled using multiple overlapping grids that are transformed into computational space. In this work, finite difference schemes are used that necessitate the addition of psuedo- or ghost-points in the overlap region of the grids for closure of the difference stencil. The functional values at these ghost points must be approximated from the values at the original grid points. This paper investigates interpolation techniques for these overset grids. An n th order interpolation scheme using Lagrange …

Novel High Frequency Silicon Carbide Static Induction Transistor-Based Test-Bed For The Acquisition Of Sic Power Device Reverse Recovery Characteristics, Kevin M. Speer, Ty R. Mcnutt, Alexander B. Lostetter, H. Alan Mantooth, Kraig J. Olejniczak

Journal of the Arkansas Academy of Science

A test system is presented that utilizes a high-frequency Silicon Carbide (SiC) Static Induction Transistor (SIT) in place of the traditional MOSFET to test reverse recovery characteristics for the new class of SiC power diodes. An easily implementable drive circuit is presented that can drive the high-frequency SIT. The SiC SIT is also compared to a commonly used Si MOSFET in the test circuit application.

Parameter Extraction Software For Compact Diode Model, Maruf Hossain, Edgar Cilio, Ty R. Mcnutt, Alexander B. Lostetter, H. Alan Mantooth

Journal of the Arkansas Academy of Science

No abstract provided.

Testing And Modeling Electrical Characteristics Of Novel Silicon Carbide (Sic) Static Induction Transistors (Sits), Avinash S. Kashyap, Sharmila D. Mangan Lal, Ty R. Mcnutt, Alexander B. Lostetter, H. Alan Mantooth

Journal of the Arkansas Academy of Science

No abstract provided.

Entrainment Of Electrical Activation By Spatio-Temporal Distributed Pacing During Ventricular Fibrillation, Yiping Gu

University of Kentucky Master's Theses

Spatio-temporal variation in action intervals during ventricular fibrillation (VF) suggestthat the excitable gap may also be distributed spatio-temporally. The observation leadus to hypothesize that distributed pacing can be used to modify and entrain electricalactivation during VF. We tested this hypothesis using simulated VF and animal studies.

We simulated VF in a 400 by 400 cell matrix. Simulation results showed that activationpattern could be entrained using spatially distributed stimulation. Up to a certain limit,increasing stimulus strength and density led to improved entrainment. Best entrainmentwas obtained by pacing at a cycle length similar to the intrinsic cycle length.

In order to verify …

Aerodynamic Effects In A Dropped Ping-Pong Ball Experiment, Mark L. Nagurka

Mechanical Engineering Faculty Research and Publications

This paper addresses aerodynamic modeling issues related to a simple experiment in which a pingpong ball is dropped from rest onto a table surface. From the times between the ball-table impacts, the initial drop height and the coefficient of restitution can be determined using a model that neglects aerodynamic drag. The experiment prompts questions about modeling the dynamics of a simple impact problem, including the importance of accounting for aerodynamic effects. Two nonlinear aerodynamic models are discussed in the context of experimental results.

Evaluating The Usefulness Of Soil Moisture (Forecasts) In Streamflow Prediction For Central Texas , Mohammed Mahmoud

Dissertations, Master's Theses and Master's Reports - Open

The past decade has brought significant advancements in seasonal climate forecasting. However, water resources decision support and management continues to be based almost entirely on historical observations and does not take advantage of climate forecasts. This study builds on previous work that conditioned streamflow ensemble forecasts on observable climate indicators, such as the El Niño-Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO) for use in a decision support model for the Highland Lakes multi-reservoir system in central Texas operated by the Lower Colorado River Authority (LCRA). In the current study, seasonal soil moisture is explored as a climate indicator …

Climatological Study Of Transport To The Pico-Nare Site Using Atmospheric Backward Trajectories, Robert Christopher Owen

Dissertations, Master's Theses and Master's Reports - Open

This study developed a transport climatology to the PICO-NARE station, in the central North Atlantic Ocean, using a 40-year set of atmospheric back trajectories. The trajectory set was subjected to a cluster analysis in order to group trajectories into six flow patterns, or clusters. An air flow probability analysis was conducted in conjunction with the cluster analysis in order to determine the source regions for flow to the site. Seasonal differences in the flow patterns were found, which included enhanced westerly flow in the winter, decreased westerly flow in the summer, and spring and fall having moderate westerly flow. The …

A Portable Eddy Covariance System For The Measurement Of Ecosystem–Atmosphere Exchange Of Co2, Water Vapor, And Energy, Dave P. Billesbach, M.L. Fischer, Margaret S. Torn, J.A. Berry

Department of Agricultural and Biological Systems Engineering: Faculty Publications

To facilitate the study of flux heterogeneity within a region, the authors have designed and field-tested a portable eddy covariance system to measure exchange of CO2, water vapor, and energy between the land surface and the atmosphere. The combination of instrumentation used in this system allows high precision flux measurements without requiring on-site infrastructure such as prepositioned towers or line power. In addition, the system contains sensors to measure a suit of soil, climatic, and energy-related parameters that are needed to quality control the fluxes and to characterize the flux footprint. The physical design and instrument packaging used in the …