Digital Commons Network^™

Internal Combustion Engine Cooling Strategies: Theory And Test, John Chastain

All Theses

Advanced internal combustion engine thermal management systems can enhance overall engine performance through the use of computer controlled cooling system actuators. Existing ground vehicle cooling systems generally have performance limitations due to the fixed behavior of the wax-based thermostat valve and crankshaft dependent operation of the coolant pump and radiator fan. Upgrading the traditional thermostat valve, water pump, and radiator fan with actuators permit real time computer control for improved temperature tracking and reduced power consumption. In this paper, the benefits associated with advanced automotive cooling systems are experimentally investigated. A 4.6L engine with a real-time data acquisition and control …

A Generalized Instantaneous Nonactive Power Theory For Parallel Nonactive Power Compensation, Yan Xu

Doctoral Dissertations

Although the definitions of active power and nonactive power in a three-phase sinusoidal power system have been accepted as a standard, it has been an issue on how to define instantaneous nonactive power in power systems with non-sinusoidal or even non- periodic voltage and/or current.

This dissertation summarizes these nonactive power theories, and a generalized instantaneous nonactive power theory is presented. By changing the parameters in the instantaneous active current and nonactive current definitions, this theory is valid for power systems with different characteristics. Furthermore, other nonactive power theories can be derived from this generalized theory by changing parameters.

This …

Fedora: An Architecture For Complex Objects And Their Relationships, Carl Lagoze, Sandy Payette, Edwin Shin, Chris Wilper

Edwin Shin

The Fedora architecture is an extensible framework for the storage, management, and dissemination of complex objects and the relationships among them. Fedora accommodates the aggregation of local and distributed content into digital objects and the association of services with objects. This allows an object to have several accessible representations, some of them dynamically produced. The architecture includes a generic Resource Description Framework (RDF)-based relationship model that represents relationships among objects and their components. Queries against these relationships are supported by an RDF triple store. The architecture is implemented as a web service, with all aspects of the complex object architecture …

Detailed Design Of The Rigidizable Inflatable Get-Away-Special Experiment, Jeremy S. Goodwin

Theses and Dissertations

The Rigidizable Inflatable Get-Away-Special Experiment is a Space Shuttle experiment that will study the effects of the zero-gravity space environment on the deployment and modal analysis of three inflatable and rigidizable tubes using a sub-Tg rigidization technique. In 2004, RIGEX was transitioned from the Space Shuttle's Get-Away-Special (GAS) canister to its Canister for All Payload Ejections (CAPE), requiring several modifications to the design. The results of these modifications, along with further refinements made to previous efforts, combine to form the detailed design of the experiment. In addition to the design modifications, analyses were conducted to determine the containment capabilities of …

Control Demonstration Of A Thin Deformable In-Plane Actuated Mirror, Gina A. Peterson

Theses and Dissertations

Current imaging satellites are limited in resolution and coverage area by the aperture size of their primary optical mirror. To get a large optical mirror into space, current launch weight and size restrictions must be overcome. Membrane-like optical mirrors can overcome these restrictions with their very lightweight and flexible properties. However, thin, deformable membrane mirrors are very susceptible to the space environment and require active control for surface stabilization and shaping. The primary goal of this research is to demonstrate that an in-plane actuated membrane-like deformable optical mirror can be controlled to optical wavelength tolerances in a closed-loop system. Fabrication …

Fedcor: An Institutional Cordra Registry, Giridhar Manepalli, Henry Jerez, Michael L. Nelson

Computer Science Faculty Publications

FeDCOR (Federation of DSpace using CORDRA) is a registry-based federation system for DSpace instances. It is based on the CORDRA model. The first article in this issue of D-Lib Magazine describes the Advanced Distributed Learning-Registry (ADL-R) [1], which is the first operational CORDRA registry, and also includes an introduction to CORDRA. That introduction, or other prior knowledge of the CORDRA effort, is recommended for the best understanding of this article, which builds on that base to describe in detail the FeDCOR approach.

Reducing Energy In Fpga Multipliers Through Glitch Reduction - Clock Power And Digit-Serial Addendum, Nathaniel Rollins, Michael J. Wirthlin

Faculty Publications

Sponsorship: NASA. In a previous paper it was shown that reducing the amount of glitches in digital designs can significantly reduce the amount of dynamic power consumption. Pipelined multipliers and a bit-serial multiplier design were used to show this. The paper failed to mention how much of the dynamic power consumption was due to the clock distribution. Also the only digit- serial multiplier digit size investigated was a digit size of 1. This paper addresses the issue of dynamic clocking power and includes results of digit-serial multipliers with larger digit sizes.

Performance Of A Three-Phase Permanent Magnet Motor Operating As A Synchronous Motor And A Brushless Dc Motor, Sophie Sekalala

LSU Master's Theses

The performance of a three-phase permanent magnet (PM) motor operating as a synchronous motor and brushless DC (BLDC) motor is discussed. The PM motor, when operating as a synchronous machine, is supplied with constant frequency, meaning constant rotor speed operation. When operating as a BLDC motor, the supply frequency changes according to the actual rotor speed. It means the speed signal is fed back to the controller, which generates the appropriate frequency to supply the stator winding. This means the BLDC motor cannot operate without a position sensor. The objective of the project was to analyze and compare the performance …