Digital Commons Network^™

Advanced Thermal Management For Internal Combustion Engines, Thomas Mitchell

All Theses

The automotive cooling system has unrealized potential to improve internal combustion engine performance through enhanced coolant temperature control and reduced parasitic losses. Advanced automotive thermal management systems use controllable actuators (e.g., smart thermostat valve, variable speed water pump, and electric radiator fan) in place of conventional mechanical cooling system components to improve engine temperature tracking over most operating ranges. To optimize advanced cooling system performance, the electro-mechanical actuators must work in harmony to control engine temperature. The design and placement of cooling components should also be considered when attempting to maximize the performance.
In this research project, two distinct vehicle …

A Comparative Study On Ontology Generation And Text Clustering Using Vsm, Lsi, And Document Ontology Models, William Taylor

All Theses

Although using ontologies to assist information retrieval and text document processing has recently attracted more and more attention, existing ontology-based approaches have not shown advantages over the traditional keywords-based Latent Semantic Indexing (LSI) method. This paper proposes an algorithm to extract a concept forest (CF) from a document with the assistance of a natural language ontology, the WordNet lexical database. Using concept forests to represent the semantics of text documents, the semantic similarities of these documents are then measured as the commonalities of their concept forests. Performance studies of text document clustering based on different document similarity measurement methods show …

Performance Of Voip Services On A Docsis Network Targeted By A Denial Of Service Attack, Benjamin Sangster

All Theses

Over 48 million end users worldwide utilize cable modems as their means of accessing the Internet at high speeds. The United States accounts for 54% of those users. Networks which provide access via cable modems utilize Data Over Cable Service Interface Specifications (DOCSIS) as their means of network management. As availability to the Internet increases (especially at high speeds supported by broadband access), so does the opportunity for malicious activity against users utilizing the Internet. Denial-of-service (DoS) attacks are one form of malicious activity and one of the most common. In commonplace Ethernet-based wired networks, a DoS attack requires relatively …

Naturally Occurring Reverse Tilt Domains In A High-Pretilt Alignment Nematic Liquid Crystal, Ruiting Wang, Timothy J. Atherton, Minhua Zhu, Rolfe G. Petschek, Charles Rosenblatt

Faculty Scholarship

A cell whose substrates were coated with the polyamic acid SE1211 (Nissan Chemical Industries) and baked at high temperatures was filled with a nematic liquid crystal in the isotropic phase. On cooling into the nematic phase, naturally occurring and temporally and thermally robust reverse tilt domains separated by thin filamentlike walls were observed. The properties of these structures are reported.

Costa Rican Court Gags Universities From Speaking Out On Cafta, Mike Leffert

NotiCen

No abstract provided.

Washington University Record, August 9, 2007

Washington University Record

No abstract provided.

The George-Anne, Georgia Southern University

The George-Anne

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Newsroom, Georgia Southern University

Newsroom (2006-2023)

• Six receive Faculty Awards for Excellence
• President’s Medal presented to Department of Music professor Braz

Modeling Wildland Fire Radiance In Synthetic Remote Sensing Scenes, Zhen Wang

Theses

This thesis develops a framework for implementing radiometric modeling and visualization of wildland fire. The ability to accurately model physical and op- tical properties of wildfire and burn area in an infrared remote sensing system will assist efforts in phenomenology studies, algorithm development, and sensor evaluation. Synthetic scenes are also needed for a Wildland Fire Dynamic Data Driven Applications Systems (DDDAS) for model feedback and update. A fast approach is presented to predict 3D flame geometry based on real time measured heat flux, fuel loading, and wind speed. 3D flame geometry could realize more realistic radiometry simulation. A Coupled Atmosphere-Fire …

Responses Of Problematic Cyanobacteria To Exposures Of Copper Containing Algaecides, O'Niell Tedrow

All Theses

Cyanobacteria (blue-green algae) are associated with production of potent hepatotoxins (Microcystis; microcystin) and dense surface and benthic mats (Lyngbya), which impede critical water resource usages. Water resource managers are in need of effective and efficient treatment techniques for these problematic algae in field situations. Applications of algaecides are considered in situations where algal problems become acute or when critical water usages are threatened. However, laboratory data are needed that accurately predict responses of algae prior to field-scale algaecide applications. Site water and algae were used in laboratory algal toxicity experiments to predict responses of the target alga following an algaecide …

C-2/C-3 Annulation And C-2 Alkylation Of Indoles With 2-Alkoxycyclopropanoate Esters., Barbora Bajtos, Ming Yu, Hongda Zhao, Brian L Pagenkopf

Chemistry Publications

The annulation reaction between various indoles and 2-alkoxycyclopropanoate esters is reported. Both high efficiency and complete stereochemical control were observed in some cases with this annulation process. A single stereocenter on the cyclopropane controls the diastereoselective formation of up to four new stereocenters. A different reaction course was observed with 3-substituted indole substrates, and an intervening C-3 to C-2-migration process arose that gives synthetically useful C-2 alkylation indole products.

Frequency Estimation Using Time-Frequency Based Methods, Cuong Mai

LSU New Orleans Theses and Dissertations

Any periodic signal can be decomposed into a sum of oscillating functions. Traditionally, cosine and sine segments have been used to represent a single period of the periodic signal (Fourier Series). In more general cases, each of these functions can be represented by a set of spectral parameters such as its amplitude, frequency, phase, and the variability of its instantaneous spectral components. The accuracy of these parameters depends on several processing variables such as resolution, noise level, and bias of the algorithm used. This thesis presents some background of existing frequency estimation techniques and proposes a new technique for estimating …

Engineering Saccharomyces Ceresisiae For The Secretion Of An Extracellular Lipase, Gaynelle Stewart

LSU New Orleans Theses and Dissertations

Developing microbial systems capable of converting low cost lipids into value added products depends on the ability to acquire substrates from the growth media. Saccharomyces cerevisiae can acquire free fatty acids from the growth media and a portion of these lipids can be converted into new lipid products. However, they cannot acquire complex lipids from the growth media unless a nonspecific lipase is included. To circumvent lipase addition, we are genetically engineering S. cerevisiae to secrete a lipase into the growth media. We selected the LIP2 gene from Yarrowia lipolytica, which encodes a nonspecific lipase. Several modifications were made to …

Divergence Model For Measurement Of Goos-Hanchen Shift, Jeffrey Frank Gray

LSU New Orleans Theses and Dissertations

In this effort a new measurement technique for the lateral Goos-Hanchen shift is developed, analyzed, and demonstrated. The new technique uses classical image formation methods fused with modern detection and analysis methods to achieve higher levels of sensitivity than obtained with prior practice. Central to the effort is a new mathematical model of the dispersion seen at a step shadow when the Goos-Hanchen effect occurs near critical angle for total internal reflection. Image processing techniques are applied to measure the intensity distribution transfer function of a new divergence model of the Goos-Hanchen phenomena providing verification of the model. This effort …

A New Method To Predict Vessel Capsizing In A Realistic Seaway, Srinivas Vishnubhotla

LSU New Orleans Theses and Dissertations

A recently developed approach, in the area of nonlinear oscillations, is used to analyze the single degree of freedom equation of motion of a oating unit (such as a ship) about a critical axis (such as roll). This method makes use of a closed form analytic solution, exact upto the rst order, and takes into account the the complete unperturbed (no damping or forcing) dynamics. Using this method very-large-amplitude nonlinear vessel motion in a random seaway can be analysed with techniques similar to those used to analyse nonlinear vessel motions in a regular (periodic) or random seaway. The practical result …

Are Moving Punctures Equivalent To Moving Black Holes?, Jonathan Thornburg, Peter Diener, Denis Pollney, Luciano Rezzolla, Erik Schnetter, Ed Seidel, Ryoji Takahashi

Faculty Publications

When simulating the inspiral and coalescence of a binary black hole system, special care needs to be taken in handling the singularities. Two main techniques are used in numerical-relativity simulations: A first and more traditional one 'excises' a spatial neighbourhood of the singularity from the numerical grid on each spacelike hypersurface. A second and more recent one, instead, begins with a 'puncture' solution and then evolves the full 3-metric, including the singular point. In the continuum limit, excision is justified by the light-cone structure of the Einstein equations and, in practice, can give accurate numerical solutions when suitable discretizations are …

Modeling And Validation Of Temperature And Concentration For Rapid Freeze Prototyping, Frances D. Bryant, Ming-Chuan Leu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Rapid Freeze Prototyping is a solid freeform fabrication process that uses water as the main build material in a cold environment to create three-dimensional parts. A eutectic sugar-water solution (C₆H₁₂O₆ – H₂O) has been used as a sacrificial material in order to create complex 3D parts with features such as overhangs. A study of the interaction of the build and support materials is presented in this paper. The temperature of both materials during deposition and subsequent cooling is modeled using a semi-empirical model and a theoretical model. A concentration model is used to …

Laser Deposition Cladding On-Line Inspection Using 3-D Scanner, Yu Yang, Todd E. Sparks, Jianzhong Ruan, Lan Ren, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Laser deposition directly deposits metal cladding to fabricate and repair components. In order to finish the fabrication or repair, 3-D shape of the deposition needs to be inspected, and thus it can be determined if it has sufficient cladding to fabricate a part after deposition process. In the present hybrid system in the Laser Aided Manufacturing Lab (LAMP) at the University of Missouri - Rolla, a CMM system is used to do the inspection. A CMM requires point-by-point contact, which is time consuming and difficult to plan for an irregular deposition geometry. Also, the CMM is a separate device, which …

Response To "Comment On 'Adhesion-Delamination Mechanics Of A Presented Rectangular Film Adhered Onto A Rigid Substrate' [J. Appl. Phys. 101, 024903 (2007)]", Kai-Tak Wan, Gang Duan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

No abstract provided.

National Board Certification And School Leadership In Louisiana, Kathleen A. Severns

LSU New Orleans Theses and Dissertations

The challenges of school accountability call for new models of school leadership. Teacher leaders are needed to create, implement, and sustain reform efforts. This study investigated whether a specific model of professional development, National Board Certification (NBC), can create sustained change aimed at improved school leadership. The research question which guided this study was: Does the National Board Certification professional development model contribute to school leadership in Louisiana? The state of Louisiana currently has approximately 1,000 teachers with National Board Certification (NBPTS, 2006f). These NBC teachers and approximately 3,000 non-NBC teachers received the online School Leadership Survey, which included survey …

Numerical Simulation Of The Evolution Of Solidification Microstructure In Laser Deposition, Zhiqiang Fan, Todd E. Sparks, Frank W. Liou, Anand Jambunathan, Yaxin Bao, Jianzhong Ruan, Joseph William Newkirk

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A predictive model is developed to simulate the evolution of the solidification microstructure during the laser deposition process. The microstructure model is coupled with a comprehensive macroscopic thermodynamic model. This model simulates dendritic grain structures and morphological evolution in solidification. Based on the cellular automata approach, this microstructure model takes into account the heterogeneous nucleation both within the melt pool and at the substrate/melt interface, the growth kinetics, and preferential growth directions of dendrites. Both diffusion and convection effects are included. This model enables prediction and visualization of grain structures during and after the deposition process. This model is applied …

Wireless Multiple Access Communication Over Collision Frequency Shift Channels, Chen Xia

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

A collision frequency shift keyed system (CFSK) using M-ary FSK signaling is investigated. CFSK is a wireless multiple access system in which users access a channel without cooperation. This results in collisions when users simultaneously transmit signals in the same frequency band. However, analysis has shown that the CFSK system has the potential to achieve greater capacities than binary multiple access systems.

In this dissertation, bounds on the multiuser capacity of the noisy synchronous and asynchronous CFSK channel are derived. Analytical models are designed for investigating these capacity results. It is shown that the capacity of the noisy synchronous CFSK …

Strain-Induced Formation Of Carbon And Boron Clusters In Boron Carbide During Dynamic Indentation, Dipankar Ghosh, Ghatu Subhash, Chee Huei Lee, Yoke Khin Yap

Department of Physics Publications

The authors found that the level of amorphization or structural disorder in boron carbide is higher when induced by dynamic indentation compared to static indentation. Visible and uv Raman spectroscopies indicate that sp²-bonded aromatic carbon clusters were formed, consistent with the detected photoluminescence spectra. Infrared absorption shows that amorphous boron clusters were created by dynamic indentation which has strain rates ∼10⁸ order higher than that introduced by static indentation. The decreased intensity of infrared stretching mode of carbon-boron-carbon (CBC) chains also suggests that amorphization is due to the collapse of B₁₁C(CBC) unit cells, which reorganize …

Interview With Trevor Baird, Baird Family Orchard, 2007 (Audio), Trevor Baird

All Sustainability History Project Oral Histories

Interview of Trevor Baird by Adam Hopfe at Portland State University on August 7th, 2007.

The interview index is available for download.

Florida Sentinel Bulletin, August 7, 2007, Gwen Hayes

Florida Sentinel Bulletin Collection

The August 7, 2007, issue of the Florida Sentinel Bulletin.

The Yale Lar Tpc, Mitchell Soderberg, A. Curioni, Bonnie T. Fleming

Physics - All Scholarship

In this paper we give a concise description of a liquid argon time projection chamber (LAr TPC) developed at Yale, and present results from its first calibration run with cosmic rays.

Modeling The Permittivity Of Two-Phase Media Containing Monodisperse Spheres: Effects Of Microstructure And Multiple Scattering, Timothy E. Doyle, David A. Robinson, Scott B. Jones, Keith H. Warnick, Brent L. Carruth

Plants, Soils, and Climate Faculty Publications

A numerical modeling approach was developed to predict the dielectric properties of heterogeneous particulate materials with arbitrary microstructures. To test the method, simulation and experimental data were acquired for the effective permittivities of various glass sphere suspensions. Both ordered lattices and random microstructures of up to 3600 spheres were modeled for volume fractions of 0.025–0.60. The electric fields in the suspensions were computed using an iterative multipole method that included multiple-scattering effects. The effective permittivities were obtained by averaging the electric field and electric displacement over a representative volume. Frequency spectra, electric field images, and single-scattering results (i.e., no particle-particle …

Ellipsometer Or Polarimeter And The Like System With Multiple Detector Element Detector In Environmental Control Chamber Including Secure Sample Access, John A. Woollam, Gregory K. Pribil, Martin M. Liphardt, James Welch

Department of Electrical and Computer Engineering: Faculty Publications

A spectrophotometer, ellipsometer or polarimeter or the like system with a spectroscopic source of wavelengths and a detector with multiple detector elements for simultaneous monitoring of a number of wavelengths in an environmental control chamber which optionally provides for secured sample entry, and methodology of use.

The Spillable Environment: Expanding A Handheld Device's Screen Real Estate And Interactive Capabilities, Jeffrey S. Clement

Theses and Dissertations

Handheld devices have a limited amount of screen real estate. If a handheld device could take advantage of larger screens, it would create a more powerful user interface and environment. As time progresses, Moore's law predicts that the computational power of handheld devices will increase dramatically in the future, promoting the interaction with a larger screen. Users can then use their peripheral vision to recognize spatial relationships between objects and solve problems more easily with this integrated system. In the spillable environment, the handheld device uses a DiamondTouch Table, a large, touch-sensitive horizontal table, to enhance the viewing environment. When …

The Barycenter Of The Numerical Range Of A Matrix, Sean A. Broughton, Roger G. Lautzenheiser, Thomas Werne

Mathematical Sciences Technical Reports (MSTR)

The numerical range W(A) of an nxn matrix A is the totality of the scalar products <Ax,x> as x varies over all unit vectors in Cⁿ The barycenter (center of mass) of the numerical range is defined geometrically as the center of mass of W(A) considered as a planar lamina with variable density and also as a limit of sample averages (<Ax₁,x₁>+...+<Ax_N,x_N>)/N. Under a wide range the sampling schemes it is shown that the barycenter is the average of the spectrum …