Engineering Commons^™

Value-Added Processing Of Rice And Rice By-Products, Rebecca C. Schramm

LSU Doctoral Dissertations

World competition has encouraged United States rice farmers and rice mills to be efficient in farming and production practices. Efforts to augment economic competitiveness include development of new varieties, improvements in milling practices, and identification of uses for rice products and by-products. The research detailed in this dissertation adds to the body of knowledge in milling practices and identification of uses for rice bran. To improve the prediction of milled rice quality at industrial scale, correlations for milling quality among laboratory, pilot, and industrial scale mills were identified for Clearfield 161. Final industrial product whiteness was ten points higher than …

Thermal Conductivity And Its Effects On The Performance Of Pcc Pavements In Mepdg, Upender Kodide

LSU Master's Theses

This study developed a standard thermal conductivity test procedure to test concrete specimens and studied factors influencing those specimens. The thermal conductivity of concrete is significantly affected by moisture content, type, and percentage of coarse aggregate; this finding was confirmed statistically by Analysis of Variance (ANOVA). The study also developed a model for predicting the thermal conductivity of concrete that varies with moisture content and the coarse aggregate percentage. To understand the effect of supplementary cementitious materials (SCMs), this study also measured thermal conductivity of control and ternary mixtures. An increase in thermal conductivity percentage due to increase in moisture …

Fabrication, Characterization, Modeling And Testing Of A Nanostructured Bulk Thermoelectric Cooler, Dinesh Pinisetty

LSU Doctoral Dissertations

New generation micro/nano devices are emerging to monitor, control and act on living systems. Particularly, in the field of cryobiology, there is a need to monitor and control temperature at the cellular level. An important step towards achieving this aim is to fabricate a novel bulk nanostructured thermoelectric cooler (TEC). As a first step towards achieving efficient localized control of temperature in biological systems, Bismuth-telluride (Bi2Te3) and Antimony-Telluride (Sb2Te3) arrays of nanowires and nanotubes were fabricated, characterized and modeled. A thermal conductivity model originally developed by Dames and Chen for superlattice nanowires was extended to nanotubes. Based on this model …

The Effect Of Anisotropic Surface Energy On The Stability Of Micro And Nano Wires, Ping Du

LSU Doctoral Dissertations

A liquid thread of radius R will break up into drops if the axial wavelength of the surface perturbation L > 2πR. If L < 2πR, the thread is stable and will remain intact. This is Rayleigh’s stability criterion based on a continuum model. We use molecular dynamics to simulate the evolution of Lennard-Jones liquid threads with equilibrium radius R = 2.3-6.6, where R has been non-dimensionalized by the distance at which the Lennard-Jones potential equals zero. We find that if R is fixed, the wavelength L is bounded by L_min and L_max. For L > L_max the thread always breaks up and stays as drops, and for L < L_min the thread remains intact. However, for L_min < L < L_max, the thread oscillates continuously among several shapes. The appearance of various shapes can be explained by the energy fluctuation of the system.

We also simulate the evolution of Lennard-Jones nanowires with equilibrium radius R = 1.57, 2.58, 3.59, and 4.60 by molecular dynamics. The wires …

Experimental Measurements During Combustion Of Moist Individual Foliage Samples, Brent M. Pickett, Carl Isackson, Rebecca Wunder, Thomas H. Fletcher, Bret Buitler, David R. Weise

Faculty Publications

Individual samples of high moisture fuels from the western and southern United States and humidified aspen excelsior were burned over a flat-flame burner at 987◦ ±12 C and 10±0.5 mol% O2. Time-dependent mass and temperature profiles of these samples were obtained and analysed. It was observed that significant amounts of moisture remained in the individual samples after ignition occurred. Temperature histories showed a plateau at 200◦–300 C at the leaf perimeter rather than at 100 C, with a plateau of 140 C for the leaf interior. Implications are that classical combustion models should be altered to reflect the behaviour of …

Probabilistic Models For Short Term Traffic Conditions Prediction, Yan Qi

LSU Doctoral Dissertations

Accurate short-term prediction of traffic condition on freeways and major arterials has become increasingly important because of its vital role in traffic management functions and various trip decisions. Given the dynamic nature of freeway traffic, this study proposed two stochastic model approaches, Hidden Markov Model (HMM) and One-Step Stochastic Model, for short-term traffic prediction during peak periods. The data used in the study are real-time traffic monitoring data gathered over 6 years on a 40-mile segment of Interstate-4 in Orlando, Florida. Both approaches are based on the traffic state transition probabilities. The HMM approach defines traffic states in a two …

Experimental And Analytical Study Of The Surface Texturing Enhanced Lubrication Elements, Yifan Qiu

LSU Doctoral Dissertations

Surface texturing is a method that modifies the frictional surface of a nominally flat tribocomponent by shallow patterns. It is found that with added patterns to the surface of a mechanical face seal or thrust bearing, their tribological performance improves, i.e. both friction and wear rate decrease. The current research concentrates on the analysis of hydrodynamic effect responsible for the performance enhancement of the spiral groove patterns and dimples on mechanical seal-like structures and the experimental evaluation of the tribological behavior of these structures. Surface textures considered are: dimple texture and spiral groove pattern. In the research on the dimple …

Estimated Impact Of Left Lane Truck Restriction On Louisiana Highway Pavement Using Mepdg, Mini Radhakrishnan

LSU Master's Theses

Truck lane restriction strategies (TLRS) are strategies used to manage truck traffic on highways by prohibiting trucks from using certain lanes in order to minimize interaction between trucks and other vehicles and currently it is under consideration for implementation in Louisiana’s multi-lane highways. One of the serious impacts of a truck lane restriction on highways is accelerated pavement damage on unrestricted lanes due to the increased truck traffic on them. The purpose of this study is to estimate the increased pavement damage on the right lane in terms of various distress caused by imposing left lane truck restriction on trucks …

Information Theoretic Approach For Assessing Image Fidelity In Photon-Counting Arrays, Srikanth R. Narravula, Majeed M. Hayat, Bahram Javidi

Electrical and Computer Engineering Faculty Research and Publications

The method of photon-counting integral imaging has been introduced recently for three-dimensional object sensing, visualization, recognition and classification of scenes under photon-starved conditions. This paper presents an information-theoretic model for the photon-counting imaging (PCI) method, thereby providing a rigorous foundation for the merits of PCI in terms of image fidelity. This, in turn, can facilitate our understanding of the demonstrated success of photon-counting integral imaging in compressive imaging and classification. The mutual information between the source and photon-counted images is derived in a Markov random field setting and normalized by the source-image’s entropy, yielding a fidelity metric that is between …

Measurement And Modeling Of Infrared Nonlinear Absorption Coefficients And Laser-Induced Damage Thresholds In Ge And Gasb, T. J. Wagner, M. A. Bohn, Ronald A. Coutu Jr., L. P. Gonzalez, J. M. Murray, K. L. Schepler, S. Guha

Electrical and Computer Engineering Faculty Research and Publications

Using a simultaneous fitting technique to extract nonlinear absorption coefficients from data at two pulse widths, we measure two-photon and free-carrier absorption coefficients for Ge and GaSb at 2.05 and 2.5 μm for the first time, to our knowledge. Results agreed well with published theory. Single-shot damage thresholds were also measured at 2.5 μm and agreed well with modeled thresholds using experimentally determined parameters including nonlinear absorption coefficients and temperature dependent linear absorption. The damage threshold for a single-layer Al₂O₃ anti-reflective coating on Ge was 55% or 35% lower than the uncoated threshold for picosecond or nanosecond …

Heat Stress Evaluation Of Protective Clothing Ensembles, Amanda Lee Pease

USF Tampa Graduate Theses and Dissertations

Clothing directly affects the level of heat stress exposure. Useful measures to express the thermal characteristics are WBGT (wet bulb globe temperature) clothing adjustment factor (CAF) or apparent total evaporative resistance (R_e,T,_a). The CAF is assigned through laboratory wear trials following a heat stress protocol in which the air temperature and humidity are progressively increased until the participant clearly loses the ability to maintain thermal equilibrium. The critical condition is the point of thermal transition and from these conditions both the CAF and Re,T,a are computed. The first objective of this study is to compare the …

Protection Of Upqc Against The Load Side Short Circuits, Iurie Axente, Malabika Basu, Michael Conlon, Kevin Gaughan

Articles

This study presents a protection scheme for protecting the series inverter of a unified power quality conditioner (UPQC). The proposed scheme protects the series inverter from overcurrents and overvoltages, which appear during short-circuit faults on the load side of the UPQC. The main protection element is a crowbar connected across the secondary of the series transformer and consists of a pair of antiparallel connected thyristors, which is governed by a simple Zener diode-based control circuit. In the case of an overvoltage, the crowbar short circuits the secondary of the transformer, thus removing the overvoltage and diverting the fault current from …

Electric Field Induced Biaxiality And The Electro-Optic Effect In A Bent-Core Nematic Liquid Crystal, Mamatha Nagaraj, Yuri Panarin, U. Manna, J. K. Vij, C. Keith, C. Tschierske

Articles

We report the observation of a biaxial nematic phase in a bent-core molecular system using polarizing microscopy, electro-optics, and dielectric spectroscopy, where we find that the biaxiality exists on a microscopic scale. An application of electric field induces a macroscopic biaxiality and in consequence gives rise to electro-optic switching. This electro-optic effect shows significant potential in applications for displays due to its fast high-contrast response. The observed electro-optic switching is explained in terms of the interaction of the ferroelectric clusters with the electric field. © 2010 American Institute of Physics.

Liquid Crystal Display Modes In A Nontilted Bent-Core Biaxial Smectic Liquid Crystal, Mamatha Nagaraj, Yuri Panarin, J. K. Vij, C. Keith, C. Tschierske

Articles

Liquid crystal display (LCD) modes associated with the rotation of the secondary director in nontilted, biaxial smectic phase of an achiral bent-core compound are demonstrated. For LCDs, we find that at least four display modes are possible using SmAPA phase of the studied material, in which the minor directors in adjacent layers are aligned antiferroelectrically. The advantages of these modes include low driving field (1–2 V/ µm), high contrast ratio 1000:1, relatively fast switching time of 0.5 ms and continuous gray scale. The molecular short axis or the polar axis in a negative dielectric, biaxial material is oriented by the …

A Machine Learning Approach To Hierarchical Categorisation Of Auditory Objects, William Coleman, Sarah Jane Delany, Charlie Cullen, Ming Yan Dr.

Articles

With the advent of new audio delivery technologies comes opportunities and challenges for content creators and providers. The proliferation of consumption modes (stereo headphones, home cinema systems, ‘hearables’), media formats (mp3, CD, video and audio streaming) and content types (gaming, music, drama & current affairs broadcasting) has given rise to a complicated landscape where content must often be adapted for multiple end-use scenarios. The concept of object-based audio envisages content delivery not via a fixed mix but as a series of auditory objects which can then be controlled either by consumers or by content creators & providers via accompanying metadata. …

Using Virtual Reality To Enhance Electrical Safety And Design In The Built Environment, Martin Barrett, Jonathan Blackledge, Eugene Coyle

Articles

Electricity and the inherent risks associated with its use in the built environment have long since been a priority for the electrical services industry and also the general public who must live and work in this environment. By its nature virtual reality has the advantage of being safe for both the user and equipment. In addition, it offers the user an opportunity to be exposed to a range of scenarios and conditions that either occur infrequently or are hazardous to replicate. This paper presents a prototype desktop virtual reality model, to enhance electrical safety and design in the built environment. …

Finding A Middleware Ict Solution For The Irish Construction Sme Sector, Alan V. Hore, Alan Redmond, Roger West

Conference papers

A key feature of the Irish construction industry is its fragmented structure. Some 16,000 businesses list their main activity as construction, yet no company has more than 3% of the total Irish output. The top 20 companies have less than 15% of total output. There is a very high number of Small to Medium Sized Enterprises (SME‟s) in the sector. However, most software products which address the specific needs of the construction industry are designed for larger companies. It is felt that the needs of the large number of SME‟s in the sector are underserved. The Construction IT Alliance (CITA) …

Transmitter Optimization In Multiuser Wireless Systems With Quality Of Service Constraints, Danda B. Rawat

Electrical & Computer Engineering Theses & Dissertations

In this dissertation, transmitter adaptation for optimal resource allocation in wireless communication systems are investigated. First, a multiple access channel model is considered where many transmitters communicate with a single receiver. This scenario is a basic component of a. wireless network in which multiple users simultaneously access the resources of a wireless service provider. Adaptive algorithms for transmitter optimization to meet Quality-of-Service (QoS) requirements in a distributed manner are studied. Second, an interference channel model is considered where multiple interfering transmitter-receiver pairs co-exist such that a given transmitter communicates with its intended receiver in the presence of interference from other …

Active Control Of Shocks And Sonic Boom Ground Signal, Bedri Yagiz

Mechanical & Aerospace Engineering Theses & Dissertations

The manipulation of a flow field to obtain a desired change is a much heightened subject. Active flow control has been the subject of the major research areas in fluid mechanics for the past two decades. It offers new solutions for mitigation of shock strength, sonic boom alleviation, drag minimization, reducing blade-vortex interaction noise in helicopters, stall control and the performance maximization of existing designs to meet the increasing requirements of the aircraft industries. Despite the wide variety of the potential applications of active flow control, the majority of studies have been performed at subsonic speeds. The active flow control …

Optimization Models And Algorithms For Spatial Scheduling, Christopher J. Garcia

Engineering Management & Systems Engineering Theses & Dissertations

Spatial scheduling problems involve scheduling a set of activities or jobs that each require a certain amount of physical space in order to be carried out. In these problems space is a limited resource, and the job locations, orientations, and start times must be simultaneously determined. As a result, spatial scheduling problems are a particularly difficult class of scheduling problems. These problems are commonly encountered in diverse industries including shipbuilding, aircraft assembly, and supply chain management. Despite its importance, there is a relatively scarce amount of research in the area of spatial scheduling.

In this dissertation, spatial scheduling problems are …

Waves In Materials With Microstructure: Numerical Simulation, Mihhail Berezovski, Arkadi Berezovski, Juri Engelbrecht

Publications

Results of numerical experiments are presented in order to compare direct numerical calculations of wave propagation in a laminate with prescribed properties and corresponding results obtained for an effective medium with the microstructure modelling. These numerical experiments allowed us to analyse the advantages and weaknesses of the microstructure model.

Temporal Scales For Transport Patterns In The Gulf Of Finland, Bert Viikmae, Tarmo Soomere, Mikk Viidebaum, Mihhail Berezovski

Publications

The basic time scales for current-induced net transport of surface water and associated time scales of reaching the nearshore in the Gulf of Finland, the Baltic Sea, are analysed based on Lagrangian trajectories of water particles reconstructed from three-dimensional velocity fields by the Rossby Centre circulation model for 1987–1991. The number of particles reaching the nearshore exhibits substantial temporal variability whereas the rate of leaving the gulf is almost steady. It is recommended to use an about 3 grid cells wide nearshore area as a substitute to the coastal zone and about 10–15 day long trajectories for calculations of the …

An Analysis Of Factors That Influence The Success Of Women Engineering Leaders In Corporate America, Letha Joye Jepson

Antioch University Dissertations & Theses

"One in 4 women entering the engineering profession leaves after age 30, while only 1 in 10 of their male counterparts does" (Perusek, 2008, p. 20). I was interested in analyzing the factors supporting women engineers’ leadership development and success. My particular focus was on women engineers in corporate environments—the personal characteristics needed for a successful career and the impacts of social support, career development, and the corporate culture on their career progression. The aspects of social support included the factors of family, friends, and significant others and the levels of supports during the woman’s career. The features of corporation …

Constrained Optimal Orbit Design For Earth Observation, Sharon D. Vtipil

Mechanical & Aerospace Engineering Theses & Dissertations

The purpose of this dissertation is to demonstrate use requirements for a satellite observation mission can be used to determine a constrained optimal orbit based on observation site requirements, observation condition restraints, and sensor characteristics. The typical Earth observation satellite is first designed according to an appropriate orbit; then the observation requirements are used to develop a target schedule. The new design process outlines the development of the appropriate orbit by incorporating user requirements at the forefront of mission planning, not after an orbit has been selected. This research shows how to map the user requirements into constraints for the …

Integration Mechanisms For Heading Perception, Elif M. Sikoglu, Finnegan J. Calabro, Scott A. Beardsley, Lucia M. Vaina

Biomedical Engineering Faculty Research and Publications

Previous studies of heading perception suggest that human observers employ spatiotemporal pooling to accommodate noise in optic flow stimuli. Here, we investigated how spatial and temporal integration mechanisms are used for judgments of heading through a psychophysical experiment involving three different types of noise. Furthermore, we developed two ideal observer models to study the components of the spatial information used by observers when performing the heading task. In the psychophysical experiment, we applied three types of direction noise to optic flow stimuli to differentiate the involvement of spatial and temporal integration mechanisms. The results indicate that temporal integration mechanisms play …

Motion Of The Multisegmental Foot In Hallux Valgus, Karl Canseco, Leah Rankine, Jason T. Long, Thomas Smedberg, Richard Marks, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Hallux valgus is a common condition characterized by lateral deviation of the large toe and medial deviation of the first metatarsal. While some gait analyses of patients with hallux valgus have been performed using plantar pressures, very little is known about the kinematics of gait in this population. The purpose of this study was to evaluate triplanar kinematics in patients with hallux valgus using a multisegmental foot model. Materials and Methods: A 15-camera Vicon Motion Analysis System was used to evaluate the gait of 38 feet in 33 patients with mild to severe hallux valgus. The Milwaukee foot model was …

Structure Prediction For The Helical Skeletons Detected From The Low Resolution Protein Density Map, Kamal Al Nasr, Weitao Sun, Jing He

Computer Science Faculty Publications

Background: The current advances in electron cryo-microscopy technique have made it possible to obtain protein density maps at about 6-10 Å resolution. Although it is hard to derive the protein chain directly from such a low resolution map, the location of the secondary structures such as helices and strands can be computationally detected. It has been demonstrated that such low-resolution map can be used during the protein structure prediction process to enhance the structure prediction.

Results: We have developed an approach to predict the 3-dimensional structure for the helical skeletons that can be detected from the low resolution protein density …

When Discrete Meets Differential: Assessing The Stability Of Structure From Small Motion, Wen-Yan Lin, Geok-Choo Tan, Loong-Fah Cheong

Research Collection School Of Computing and Information Systems

We provide a theoretical proof showing that under a proportional noise model, the discrete eight point algorithm behaves similarly to the differential eight point algorithm when the motion is small. This implies that the discrete algorithm can handle arbitrarily small motion for a general scene, as long as the noise decreases proportionally with the amount of image motion and the proportionality constant is small enough. This stability result extends to all normalized variants of the eight point algorithm. Using simulations, we show that given arbitrarily small motions and proportional noise regime, the normalized eight point algorithms outperform their differential counterparts …

Crctol: A Semantic Based Domain Ontology Learning System, Xing Jiang, Ah-Hwee Tan

Research Collection School Of Computing and Information Systems

Domain ontologies play an important role in supporting knowledge‐based applications in the Semantic Web. To facilitate the building of ontologies, text mining techniques have been used to perform ontology learning from texts. However, traditional systems employ shallow natural language processing techniques and focus only on concept and taxonomic relation extraction. In this paper we present a system, known as Concept‐Relation‐Concept Tuple‐based Ontology Learning (CRCTOL), for mining ontologies automatically from domain‐specific documents. Specifically, CRCTOL adopts a full text parsing technique and employs a combination of statistical and lexico‐syntactic methods, including a statistical algorithm that extracts key concepts from a document collection, …