Engineering Commons^™

Navigation Aids In Route Training: Increase Navigation Speed, Decrease Route Retention?, John Holmquist

Electronic Theses and Dissertations

In the case of one car following another to a destination, it is very effective at getting the second vehicle to the destination quickly; however, the driver of the second car may not learn the route. Yet, for individuals, such as firefighters, law enforcement, and military personnel, it is imperative that a route be learned quickly and accurately and that an awareness of the situation is maintained while they traverse the given route. This leads to three questions, (a) will navigation aids affect initial route navigation; (b) will navigation aids affect retention; and (c) will navigation aids affect situation awareness …

Adapting The Modified Cam Clay Constitutive Model To The Computational Analysis Of Dense Granular Soils, Jose Arvelo

Electronic Theses and Dissertations

The computational constitutive Modified Cam Clay Model (MCCM) was developed at Cambridge to study the behavior of clays and has been proven to be effective. In this study, this model is extended to the case of dense sands to analyze the accuracy of the stress-strain behavior. This analysis is based on triaxial test data applied to remolded and compacted sand samples under drained conditions. The laboratory triaxial tests were performed by the Florida Department of Transportation to research the permeability effect in sandy soils compacted up to 95% of maximum unit weight at the optimum moisture content. Each soil sample …

Thermo And Kinetic Studies On The Sorption And Desorption Of Hydrophobic Organic Contaminants In Sediments, Yunzhou Chai

LSU Doctoral Dissertations

This study investigated the correlation of desorption resistance of hydrophobic organic contaminants (HOCs) in sediment and the heterogeneity of sediment organic matter (SOM). The amorphous and condensed phase organic carbon contents were defined by the method of Gustafsson et al. (1997) using thermal oxidation of sediment under 375°C. The desorption-resistant fraction of contaminants in sediments was operationally defined as the fraction that could not be removed by the adsorbent XAD-2. The correlation of the desorption-resistant fraction with sediment organic carbon characteristics was evaluated for both laboratory-inoculated and field-contaminated sediments. No strong correlation between the desorption resistant fraction in laboratory-inoculated sediments …

Mathematical Models For Estimating Volatile Chemical Emissions From Dredging Operations, Kenneth Alexander Fountain

LSU Master's Theses

Dredging operations have been a common remediation for contaminated sediment in an effort to reduce the harmful impact on the environment. The objective of this research was to create models used for estimating chemical release to air from remediating the Indiana Harbor and Canal (IHC) as three separate dredging operations; the Dredge Site, Exposed DM CDF, and Ponded CDF. The evaporative flux estimations are based on a two-resistance mass transport path inclusive of both the molecular diffusion in porous media and interfacial airside mass transport resistances. Several chemodynamic algorithms were used in calculating key transport parameters. Laboratory tests were performed …

Optimization Of Cell Density And Dilution Rate In Pichia Pastoris Continuous Fermentations For Production Of Recombinant Proteins, Mehmet Inan, Michael M. Meagher, Wenhui Zhang, Chih Ping Liu

Papers in Biomolecular Engineering

This paper provides an approach for optimizing the cell density (Xc) and dilution rate (D) in a chemostat for a Pichia pastoris continuous fermentation for the extracellular production of a recombinant protein, interferon τ (INF-τ). The objective was to maximize the volumetric productivity (Q, mg INF-τ I-1 h-1), which was accomplished using response surface methodology (RSM) to model the response of Q as a function of Xc and D within the ranges 150 ≤ Xc ≤ 450 g cells (wet weight) l-1 and 0.1 μm ≤D ≤ 0.9 μm (μm =0.0678 h-1, the maximum specific growth rate obtained from a …

Software Quality Strategic Driver Model (Sq-Sdm 11), Ronan Fitzpatrick

Other resources

No abstract provided.

Development Of A Numerical Model To Simulate Pressure Distributions In Ultrasound Angioplasty, Graham Gavin, Garrett Mcguinness, Finbar Dolan, M.S. Hashmi

Conference Papers

Ultrasound Angioplasty has been shown to be effective in the removal and re-canalising of blockages in arteries (Siegel RJ, 1993). The ultrasound is delivered via a wire waveguide to the lesion location. The wire, generally, has a ball-tip at the distal end to increase transmission of the ultrasound to the surrounding fluid by causing the ball-tip to oscillate between 20– 45kHz and with displacements of up to 100mm peak-to-peak (Atar, 1999 and Yock, 1997). Pressure waves, micro streaming, cavitation and direct contact with the oscillating ball-tip affect the blockage. Most work to date has concentrated on a spherical ball-tip geometry …

Smoothing With Mixed Model Software, Long Ngo, M P. Wand

Faculty of Engineering and Information Sciences - Papers: Part A

Smoothing methods that use basis functions with penalization can be formulated as fits in a mixed model framework. One of the major benefits is that software for mixed model analysis can be used for smoothing. We illustrate this for several smoothing models such as additive and varying coefficient models for both S-PLUS and SAS software. Code for each of the illustrations is available on the Internet.

Model State Land Use Legislation For New England, New England Environmental Finance Center, Muskie School Of Public Service

Legislation

Sprawl is neither the ordained nor the inevitable outcome upon the New England landscape. A coordinated response to sprawl by the public and private sectors is possible, and could dramatically improve land use patterns and reduce the cost of local government. For the New England states, such a response would include, among other elements, legislation to eliminate existing gaps in the land use laws of each state – gaps that presently encourage or sanction sprawling development. It would also include incentives for municipalities to think beyond their borders and to act with greater efficiency and effect. It is the purpose …

Sculpting: An Improved Inside-Out Scheme For All Hexahedral Meshing, Kirk S. Walton

Theses and Dissertations

Generating all hexahedral meshes on arbitrary geometries has been an area of important research in recent history. Hexahedral meshes have advantages over tetrahedral meshes in structural mechanics because they provide more accurate results with fewer degrees of freedom. Many different approaches have been used to create all-hexahedral meshes. Grid-based, inside-out, or superposition meshing all refer to a similar meshing approach that is a very common mesh generation technique. Grid-based algorithms provide the ability to generate all hexahedral meshes by introducing a structured mesh that bounds the complete body modeled, marking hexahedra to define an interior and exterior mesh, manipulating the …

Channel Probing For An Indoor Wireless Communications Channel, Brandon Hunter

Theses and Dissertations

The statistics of the amplitude, time and angle of arrival of multipaths in an indoor environment are all necessary components of multipath models used to simulate the performance of spatial diversity in receive antenna configurations. The model presented by Saleh and Valenzuela, was added to by Spencer et. al., and included all three of these parameters for a 7 GHz channel. A system was built to measure these multipath parameters at 2.4 GHz for multiple locations in an indoor environment. Another system was built to measure the angle of transmission for a 6 GHz channel. The addition of this parameter …

The Development Of Relationships Between Constituent Concentrations And Generic Hydrological Variables, Carmen T. Agouridis, Dwayne R. Edwards

Biosystems and Agricultural Engineering Faculty Publications

The collection and analysis of samples from storm events constitutes a large portion of the effort associated with water quality research. Estimating concentrations or loads from these events is often difficult. The equipment necessary to analyze the samples and the required laboratory resources are typically significant expenses incurred by the researcher. One potential method to reduce these costs is through the development of generic relationships between concentrations and easily measured variables such as dimensionless flow rate or time. The benefits recognized from such an effort include a reduction in the number of required samples, resulting in a reduction in cost. …

Www Sites Vs. Applications Software: The Dais Model, Lejla Vrazalic, Peter N. Hyland

Faculty of Engineering and Information Sciences - Papers: Part A

Since the advent and widespread use of the Internet, it has become apparent that there are significant differences between applications software and WWW sites which warrant a re-examination of HCI design and evaluation methods. Previous research has identified and documented the factors which differentiate between applications software and WWW sites, however a well defined model of these differences and their origins was not available. This paper defines such a model of Distinguishing Attributes for Informational Sites (DAIS). © 2003 ACM.

Review Of Mathematical Model For Proton Exchange Membrane Fuel Cell, Shan-Hai Ge, Bao-Lian Yi, Hua-Min Zhang

Journal of Electrochemistry

In the review with 49 references, the mathematical models for proton exchange membrane fuel cell (PEMFC) were summarized. The mechanistic model and empirical model were introduced. Transfer in the membrane, catalyst layer,diffusion layer and flow field of PEMFC were described. The importance of water and heat management was analyzed. The dimension, complexity and solving methods of the PEMFC model were discussed. The importance and validity to develop a model with time dimension are put forward.

Creep And Creep-Recovery Models For Wood Under High Stress Levels, Zhiyong Cai, Kenneth J. Fridley, Michael O. Hunt, David V. Rosowsky

Civil and Environmental Engineering and Construction Faculty Research

Forty small clear southern pine specimens were loaded under third-point bending to examine creep and creep-recovery behavior for wood under high stress levels. Stress levels of between 69% and 91% of the predicted static strength were applied for 23 h with 1 h allowed for recovery, and the resulting deflection vs. time behavior was studied. The experimental creep and creep-recovery behavior was modeled using modified power law functions. The results indicate that these functions provide the best fit to both primary and secondary experimental data. The empirical models can be used to simulate the viscoelastic behavior of wood under high …

Long-Term Benefits Of Stabilizing Soil Subgrades, Tommy C. Hopkins, Tony L. Beckham, Liecheng Sun, Bixian Ni, Barry Butcher

Kentucky Transportation Center Research Report

Chemical admixtures have been used extensively since the mid-eighties in Kentucky to improve bearing strengths of soil subgrades. Most pavements in Kentucky are constructed on clayey soils. Although short-term observations at a small number of sites showed that chemical stabilization worked very well, a need existed to perform a more comprehensive review and to assess the long-term benefits of this subgrade stabilization method. The main intent of this study was an attempt to address questions concerning bearing strengths, longevity, durability, structural credit, economics, and performance of pavements resting on soil subgrades mixed with chemical admixtures. In-depth field and laboratory studies …

Development Of A Phosphorus Management Model To Address Filamentous Algae In A Shallow, Subtropical, Urban Hypereutrophic Lake, Jennifer Eileen Ruley

LSU Master's Theses

City Park Lake is a shallow, subtropical, urban hypereutrophic lake located in Baton Rouge, Louisiana. By the late 1970’s, this artificial lake had experienced extreme eutrophication and suffered from frequent algal blooms and fish kills. Restoration of City Park Lake occurred in 1983 and consisted of dredging nutrient-laden sediments and the rehabilitation of sewage pipelines. Pre- and post-restoration water quality monitoring programs have provided valuable information by which to gage the long-term success of the restoration work. Following the restoration effort, dramatic improvements were observed in the lake including lower nitrogen, phosphorus and chlorophyll-a concentrations, reduced frequencies in algal blooms …

Defining Benthic Organism Exposure: Bioavailability And Effects Of Non-Polar Organics, Marc Samuel Greenberg

Browse all Theses and Dissertations

Laboratory and field tests were conducted to evaluate the hypothesis that factors such as the total organic carbon (TOC) contents and groundwater-surface water interactions (GSI) in the sediments can affect chemical desorption, bioavailability and benthic organism exposure. Laboratory studies were conducted with the polycyclic aromatic hydrocarbon fluoranthene (FLU) and the herbicide trifluralin (TF). Toxicokinetic parameters were determined for Lumbriculus variegatus and Hyalella azteca in water-only exposures to 0, 5, 20 and 50 µg/L of the compounds and bioaccumulation was measured during exposures to 0, 100 and 200 mg/kg of FLU and TF spiked onto sediments from Lakes Erie and Huron. …

Development Of Hiv Model And Its Simulation, D. K. Chaturvedi, Pritam Singh, S. K. Gaur, D. S. Mishra

D. K. Chaturvedi Dr.

The article discusses model developmetn for HIV infected population using the System Dynamics technique. The technique has an advantage over conventional modeling technique as it is dependent more on causal relationships that involve qualitative and quantitative variables to model socioeconomic problems of a complex nature. The model has been simulated and the results haven been compared witht he available data.

Resilient Modulus Of Kentucky Soils, Tommy C. Hopkins, Tony L. Beckham, Charlie Sun, Bixian Ni

Kentucky Transportation Center Research Report

In recent years, the American Association of State Highway Transportation Officials (AASHTO) has recommended the use of resilient modulus for characterizing highway materials for pavement design. This recommendation evolved as of a result of a trend in pavement design of using mechanistic models, which are based on the theory of elasticity (layered elastic analysis) or linear and non-linear, finite elements (and finite difference methods), or a combination of both of those theoretical approaches. Although much progress has been made in recent years in developing mathematical, mechanistic pavement design models, results obtained from those models are only as good as the …

Software Quality Strategic Driver Model (Sq-Sdm), Ronan Fitzpatrick

Other resources

No abstract provided.

Does The Model Matter For Greg Estimation? A Business Survey Example, Dan Hedlin, Hannah Falvey, Raymond Chambers, Phillip Kokic

Faculty of Engineering and Information Sciences - Papers: Part A

Although asymptotically design-unbiased, GREG estimators may produce bad estimates. The article examines the behaviour of GREG estimators when the underlying models are misspecified. It shows how an efficient GREG estimator was found for a business survey that posed some problems. The work involved data exploration in several steps, combined with analyses of g-weights, residuals and standard regression diagnostics. We discuss two diagnostics for whether a GREG estimate is reasonable or not. A common justification for the use of GREG estimators is that, being asymptotically design unbiased, they are relatively robust to model choice. However, we show that the property of …

Wiener Model Identification And Predictive Control For Dual Composition Control Of A Distillation Column, H H J Bloemen, C T. Chou, T J J Van Den Boom, V Verdult, M Verhaegen, T C. Backx

Faculty of Engineering and Information Sciences - Papers: Part A

The benefits of using the Wiener model based identification and control methodology presented in this paper, compared to linear techniques, are demonstrated for dual composition control of a moderate-high purity distillation column simulation model. An identification experiment design is presented which enables one to identify both the low and high gain directions of the distillation column, properties which are important for control and hard to identify in a conventional identification experiment setup as is demonstrated in the paper. Data from the proposed experiment design is used for indirect closed-loop identification of both a linear and a Wiener model, which shows …

North Carolina State University Center For Minority Engineer Development, Tony L. Mitchell, Sarah A. Rajala, Laura J. Bottomley, Mary Clare Robbins

Sarah A. Rajala

North Carolina State University, located in Raleigh, North Carolina, USA, is the largest state-supported university of the sixteen-campus University of North Carolina educational system. The College of Engineering at NC State University is among the best in the country, offering outstanding degree programs and preparing students for exciting and rewarding careers. Our graduates are heavily recruited internationally for positions in a variety of settings, including business management, construction, transportation, hardware and software development, computer engineering and design. The College of Engineering comprises 10 departments offering 16 BS, 17 MS, and 14 Ph.D. degree programs and conducts the largest undergraduate and …

The Software Quality Star (Sq-Star), Ronan Fitzpatrick

Other resources

Usability is a significant factor in the creation of quality software products which is an important focus of the software engineering syllabus. Usability is also a significant factor in the study of Human-Computer Interaction (HCI). Despite the connection, software quality and the rigours of the software engineering discipline are not used in the teaching of HCI and visa versa. Consequently, students undertaking software engineering courses are not fully exposed to usability issues and HCI students often miss out on the disciplines of software engineering. This paper presents a quality focused conceptual model - the Software Quality Star - which can …

Microscopic Treatment Of Substrate Effects On Linear And Quadratic Optical Response Of Model Langmuir-Blodgett Multilayers, Marc In Het Panhuis, R W. Munn

Australian Institute for Innovative Materials - Papers

Microscopic calculations are reported of linear and quadratic nonlinear optical response in model Langmuir-Blodgett films on a substrate, which is treated by the method of images. The effect of the substrate is significant in the first two layers, and is greatest for tilted molecules with their head groups adjacent to the substrate. The main qualitative effect is to lower the symmetry relative to a free-standing film. Calculations for stearic acidfilms show that the substrate effect is most important for molecules with nonuniform response on a metallic substrate.

Microscopic Calculations Of Linear And Quadratic Optical Response In Model Langmuir-Blodgett Multilayers, Marc In Het Panhuis, R W. Munn

Australian Institute for Innovative Materials - Papers

Microscopic calculations are reported of linear and quadratic nonlinear optical response in Langmuir–Blodgett films. The films are modeled as ordered layers of molecules that can tilt from the vertical and have a higher polarizability and first hyperpolarizability in the head than in the tail. The local electric field varies little after the first layer and negligibly after the second, which simplifies the analysis. Tilted two-layer Y-type films can have quadratic susceptibility components as large as X- or Z-type ones. Overall the results provide a systematic account of the linear and nonlinear optical properties as a function of …

A Physical Model For The Hard X-Ray Background, R J. Wilman, A C. Fabian, Paul E J Nulsen

Faculty of Engineering and Information Sciences - Papers: Part A

We combine a semi-analytic galaxy formation model with a prescription for the obscured growth of massive black holes, to reproduce the hard X-ray background (XRB), the local 2–10 keV active galactic nuclei (AGN) luminosity function and the source counts, including recent Chandra results. The model also complies with constraints on the AGN contribution to the far-infrared and submillimetre backgrounds.

The comoving density of luminous AGN [L(2-10keV) > 10⁴⁴ erg s^-1, in the unabsorbed rest-frame] in the model declines sharply since z=2, mimicking the observed evolution of the quasar population. The abundance of lower luminosity AGN simultaneously increases, and …

Modeling Nitrogen Evolution During Coal Pyrolysis Based On A Global Free-Radical Mechanism, Steven T. Perry, Thomas H. Fletcher

Faculty Publications

A global free-radical mechanism and an associated rate equation for the evolution of light gas nitrogen during coal devolatilization are presented. The light gas nitrogen rate equation was used to modify an existing nitrogen model so that only a network devolatilization model and coal-specific chemical structural input data are required to adequately predict light gas nitrogen release at a variety of pyrolysis conditions. Model predictions show good agreement with nitrogen release data from pyrolysis of coals of rank from lignite to low volatile bituminous at heating rates from 0.5 to 10⁵ K/s, temperatures as high as 2300 K, and …

Interval Matching And Control For Hexahedral Mesh Generation Of Swept Volumes, Jason F. Shepherd

Theses and Dissertations

Surface meshing algorithms require certain relationships among the number of intervals on the curves that bound the surface. Assigning the number of intervals to all of the curves in the model such that all relationships are satisfied is called interval assignment. Volume meshing algorithms also require certain relationships among the numbers of intervals on each of the curves on the volume. These relationships are not always captured by surface meshing requirements. This thesis presents a news technique for automatically identifying volume constraints. In this technique, volume constraints are grouped with surface constraints and are solved simultaneously. A sweepable volume has …