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Full-Text Articles in Engineering

Simulation Of Fixed– And Variable–Rate Application Of Granular Materials, John Patrick Fulton, Scott A. Shearer, Timothy S. Stombaugh, Michael E. Anderson, Thomas F. Burks, Stephen F. Higgins Sep 2003

Simulation Of Fixed– And Variable–Rate Application Of Granular Materials, John Patrick Fulton, Scott A. Shearer, Timothy S. Stombaugh, Michael E. Anderson, Thomas F. Burks, Stephen F. Higgins

Biosystems and Agricultural Engineering Faculty Publications

Research has shown that application errors exist with variable–rate technology (VRT) systems. Consequently, using prescription maps for economic and agronomic analyses can generate misleading results. The intent of this article was to develop and validate a spatial data model for generating “as–applied” maps to support the advancement of precision agriculture practices. Previous research modified ASAE Standard S341.2 to include a 2–D matrix of collection pans to assess fixed–rate and variable–rate (VR) deposition of granular fertilizers and agricultural lime from a spinner disc spreader. The “as–applied” spatial data model uses GIS functionality to generate “as–applied” surfaces by merging distribution patterns and …


Channel Probing For An Indoor Wireless Communications Channel, Brandon Hunter Mar 2003

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 …


Analysis And Modeling Of Polysilicon Critical Dimensions, Jasper P. Munson Jan 2003

Analysis And Modeling Of Polysilicon Critical Dimensions, Jasper P. Munson

Journal of the Microelectronic Engineering Conference

The objective of the project was to evaluate polysilicon CD etch bias as it was affected by etch time, measurement feature within the exposure field, and the product being measured. Characterization of the trends has generated a summarizing model that uses etch time, measurement feature, and product type as significant factors in determining polysilicon CD etch bias. Etch time was found to be a continuous factor, while measurement site and product type were categorical. Measurement Site A was found to be independent of measurement Site B, independent of Site C, etc., as well as Product 1 was found independent of …


Heat Transfer In Outdoor Aquaculture Ponds, Jonathan Lamoureux Jan 2003

Heat Transfer In Outdoor Aquaculture Ponds, Jonathan Lamoureux

LSU Master's Theses

An energy balance was developed for heated and unheated earthen aquaculture ponds to 1) determine the relative importance of energy transfer mechanism affecting pond temperature; 2) predict pond temperatures; 3) estimate the energy required to control pond temperatures, and 4) recommend efficient heating and cooling methods. PHATR (Pond Heating and Temperature Regulation), a computer program using 4th order Runge-Kutta numerical method was developed to solve the energy balance using weather, flow rate and pond temperature data. By comparing measured and modeled pond temperatures, the average difference (the average bias) was 0.5°C for unheated ponds and 2.4°C for heated ponds. The …


Somos Simulation/Optimization Modeling System, Richard C. Peralta Jan 2003

Somos Simulation/Optimization Modeling System, Richard C. Peralta

Civil and Environmental Engineering Faculty Publications

SOMOS (Simulation / Optimization Modeling System) is a family of simulation / optimization (S/O) modules to aid in optimally managing water resources. SOMOS results from twenty years experience developing optimization models and applying them to real-world problems, including 11 pump-and-treat (PAT) systems and numerous water supply problems. SOMOS significantly improves water management or designs and saves money. Its user’s manual provides excellent training in principles of applying optimization to managing aquifer and stream-aquifer systems. It is being incorporated with powerful groundwater modeling and visualization packages.


Practical Simulation /Optimization Modeling For Groundwater Quality And Quantity Management, Richard C. Peralta, Ineke M. Kalwij, Shengjun Wu Jan 2003

Practical Simulation /Optimization Modeling For Groundwater Quality And Quantity Management, Richard C. Peralta, Ineke M. Kalwij, Shengjun Wu

Civil and Environmental Engineering Faculty Publications

Software for mathematically optimizing groundwater management has improved significantly in recent years. The SOMOS code can readily handle large complex plume and water management problems. Most recently, it developed a least-cost $40.82M 30-yr pumping strategy for the 6.58 mile long Blaine NAD plume. That strategy was 19 percent better than the strategy developed simultaneously by an experienced consultant using normal trial and error simulation procedures. The management problem involved 60 stress periods, and well installation and pumping rates that could change every 10 periods. The optimal strategy employed 10 new wells. At a simpler site, SOMOS helped select robust strategies …


Modeling A Mississippi River Diversion Into A Louisiana Wetland, Stephan Alexander Capps Jan 2003

Modeling A Mississippi River Diversion Into A Louisiana Wetland, Stephan Alexander Capps

LSU Master's Theses

Wetland loss has significant impacts. Numerous loss mechanisms have been hypothesized, and a greater number of solutions have been proposed. One proposed solution is to divert river water into a degraded area with the intent of increasing sedimentation, introducing nutrients, and/or decreasing salinity within the wetland. However, wetland hydraulics and hydrology are complex processes and any hydrologic modification may result in unintended consequences. Predicting these consequences can be problematic due to the complexity and difficulty associated with proper modeling of the hydraulics and topography. The primary objective of this study is to evaluate the suitability of established one- and two-dimensional …


Lunar Lava Tube Radiation Safety Analysis, Giovanni De Angelis, J. W. Wilson, M. S. Clowdsley, J. E. Nealy, D. H. Humes, J. M. Clem Dec 2002

Lunar Lava Tube Radiation Safety Analysis, Giovanni De Angelis, J. W. Wilson, M. S. Clowdsley, J. E. Nealy, D. H. Humes, J. M. Clem

Mathematics & Statistics Faculty Publications

For many years it has been suggested that lava tubes on the Moon could provide an ideal location for a manned lunar base, by providing shelter from various natural hazards, such as cosmic radiation, meteorites, micrometeoroids, and impact crater ejecta, and also providing a natural environmental control, with a nearly constant temperature, unlike that of the lunar surface showing extreme variation in its diurnal cycle. An analysis of radiation safety issues on lunar lava tubes has been performed by considering radiation from galactic cosmic rays (GCR) and Solar Particle Events (SPE) interacting with the lunar surface, modeled as a regolith …


Steady State Simulation Of Ysz Intermediate-Temperature Fuel Cell, Zi-Jing Lin, Ye Gu, Xiao-Hua Zhang Nov 2002

Steady State Simulation Of Ysz Intermediate-Temperature Fuel Cell, Zi-Jing Lin, Ye Gu, Xiao-Hua Zhang

Journal of Electrochemistry

With a coupled 2D electrochemical and thermal modeling software, the characteristics of the steady state operation of the intermediate-temperature fuel cell with thin yttria-stabilized zirconia(YSZ) electrolyte was analyzed. The parameters of I-V equation were obtained from fitting the experiment results and the choice of grid points was determined by balancing the accuracy requirement and computational efficiency. The temperature fields at different operation circumstances such as flow designs, material choices for interconnect, were examined. The dependences of the output power and cell efficiency on the operating voltage at different temperatures were studied. Based upon the analysis of the temperature profile, it …


Development Of A Finite-Element Stored Grain Ecosystem Model, Michael D. Montross, Dirk E. Maier, Kamyar Haghighi Sep 2002

Development Of A Finite-Element Stored Grain Ecosystem Model, Michael D. Montross, Dirk E. Maier, Kamyar Haghighi

Biosystems and Agricultural Engineering Faculty Publications

An axisymmetric finite–element model was developed that predicts the heat, mass, and momentum transfer that occurred in upright corrugated steel storage structures due to conduction, diffusion, and natural convection using realistic boundary conditions. Weather data that included hourly total solar radiation, wind speed, ambient temperature, and relative humidity were used to model the temperature, moisture content, dry matter loss, and maize weevil development during storage with no aeration, and with ambient and chilled aeration. Periods of aeration were simulated assuming a uniform airflow rate through the grain mass. Heat and mass balances were used to calculate the temperature and absolute …


Validation Of A Finite-Element Stored Grain Ecosystem Model, Michael D. Montross, Dirk E. Maier, Kamyar Haghighi Sep 2002

Validation Of A Finite-Element Stored Grain Ecosystem Model, Michael D. Montross, Dirk E. Maier, Kamyar Haghighi

Biosystems and Agricultural Engineering Faculty Publications

An axisymmetric finite–element model was validated with respect to predicting the heat, mass, and momentum transfer that occurred in upright corrugated–steel storage bins due to conduction, diffusion, and natural convection using realistic boundary conditions. Hourly weather data that included hourly total solar radiation, wind speed, ambient temperature, and relative humidity were used to model the corn temperature and moisture content during storage with no aeration, and with ambient and chilled aeration. Periods of aeration were simulated assuming a uniform airflow rate through the grain mass. Sixteen bins with a capacity of 11.7 t each and instrumented with temperature cables were …


Models Of Soil Moisture Dynamics In Ecohydrology: A Comparative Study, Andrew J. Guswa, M. A. Celia, I. Rodriguez-Iturbe Sep 2002

Models Of Soil Moisture Dynamics In Ecohydrology: A Comparative Study, Andrew J. Guswa, M. A. Celia, I. Rodriguez-Iturbe

Engineering: Faculty Publications

An accurate description of plant ecology requires an understanding of the interplay between precipitation, infiltration, and evapotranspiration. A simple model for soil moisture dynamics, which does not resolve spatial variations in saturation, facilitates analytical expressions of soil and plant behavior as functions of climate, soil, and vegetation characteristics. Proper application of such a model requires knowledge of the conditions under which the underlying simplifications are appropriate. To address this issue, we compare predictions of evapotranspiration and root zone saturation over a growing season from a simple bucket-filling model to those from a more complex, vertically resolved model. Dimensionless groups of …


On Using The Equivalent Conductivity To Characterize Solute Spreading In Environments With Low-Permeability Lenses, Andrew J. Guswa, David L. Freyberg Aug 2002

On Using The Equivalent Conductivity To Characterize Solute Spreading In Environments With Low-Permeability Lenses, Andrew J. Guswa, David L. Freyberg

Engineering: Faculty Publications

Solute transport through highly heterogeneous geologic environments with connected pathways through high-conductivity material and lenses of low permeability often is not described well by a macroscopic advection-dispersion equation. An upscaled advection-dispersion model with a uniform velocity and dispersion coefficient does not predict the significant plume asymmetry and extended tailing often observed over finite distances in such environments. We investigate the hydrogeologic conditions under which an upscaled model must incorporate another mechanism to describe the extended tailing arising from slow advection through and diffusion into and out of low-permeability inclusions. We use high-resolution simulations to determine ground truth transport results for …


3d Finite Element Modeling Of The Welding Process, Ihab Fanous Zakaria Jun 2002

3d Finite Element Modeling Of The Welding Process, Ihab Fanous Zakaria

Archived Theses and Dissertations

The modeling and simulation of the welding process has been of main concern for different fields of applications. It is used mainly to check for the residual stresses generated due to welding. These stresses may reach a value near the yielding level and may cause several failure types in the welded strnctures. Several attempts have been clone in analyzing the welding process using different approaches. Analytical methods have been developed with many approximations and assumptions to handle the highly non-linear behavior of the problem. On the other hand, experimental methods in monitoring the residual stresses in a welded structure may …


Modeling And Test Of Pixel Cross-Talk In Hgcdte Focal Plane Arrays, Thomas J. Sanders, E. Lee Caraway, Glenn T. Hess, Gwendolyn W. Newsome, Theodore Fischer Oct 2001

Modeling And Test Of Pixel Cross-Talk In Hgcdte Focal Plane Arrays, Thomas J. Sanders, E. Lee Caraway, Glenn T. Hess, Gwendolyn W. Newsome, Theodore Fischer

Electrical Engineering and Computer Science Faculty Publications

Mercury Cadmium Telluride focal plane arrays with well over 1000 pixels have been fabricated for a number of years. These FPA's have been built as large two-dimensional arrays of HgCdTe p-n junction diodes on a single CdTe or CdZnTe substrate. Sensitivity of each pixel to impinging radiation is one of the most important quality factors for these devices. However, material parameters, which give diode high sensitivity, are the same as those that cause cross talk between adjacent diodes in the array. This cross talk causes a blurred image and in general is a detrimental factor for the FPA system. The …


Simulation Modeling For Integrated E-Supply Chain Management, Pornsarun Wirojanagud May 2001

Simulation Modeling For Integrated E-Supply Chain Management, Pornsarun Wirojanagud

Theses

E-supply chain management is an emerging area of interest as companies begin to explore the Internet's potential to restructure supply chain relationships. The environmental impact of e-supply chain management is a critical issue towards sustainability. This thesis discusses and models an integrated e-supply chain network accounting for material and information flows throughout the supply chain in order to analyze the environmental implications and tradeoffis with other system characteristics. The network structure has complex interactions between various entities. In order to understand and analyze dynamic performance, a discrete-event simulation approach is utilized. An integrated tool was developed using the Arena simulation …


Task Specific Uncertainty In Coordinate Measurement, R. G. Wilhelm, R. Hocken, H. Schwenke Jan 2001

Task Specific Uncertainty In Coordinate Measurement, R. G. Wilhelm, R. Hocken, H. Schwenke

Department of Mechanical and Materials Engineering: Faculty Publications

Task specific uncertainty is the measurement uncertainty associated with the measurement of a specific feature using a specific measurement plan. This paper surveys techniques developed to model and estimate task specific uncertainty for coordinate measuring systems, primarily coordinate measuring machines using contacting probes. Sources of uncertainty are also reviewed.


Modeling Lithium Intercalation In A Porous Carbon Electrode, Gerardine G. Botte, Ralph E. White Jan 2001

Modeling Lithium Intercalation In A Porous Carbon Electrode, Gerardine G. Botte, Ralph E. White

Faculty Publications

No abstract provided.


Emi Model Validation And Standard Challenge Problems, Bruce Archambeault, James L. Drewniak Mar 2000

Emi Model Validation And Standard Challenge Problems, Bruce Archambeault, James L. Drewniak

Electrical and Computer Engineering Faculty Research & Creative Works

A joint effort of the IEEE/EMC Society TC-9 Committee and the Applied Computational Electromagnetic Society (ACES) resulted in a central web location for contributors who will provide model and measurement data to share and compare with others. In addition to the data repository, a set of standard challenge problems have been proposed over the past few years, and are located at the web site. The site will be carefully monitored by a review committee to insure only high-quality information is posted on the site.


Improving The Accuracy Of Predicting Effectiveness Factors For Mth Order And Langmuir Rate Equations In Spherical Coordinates, Jianhui Hong, William C. Hecker, Thomas H. Fletcher Jan 2000

Improving The Accuracy Of Predicting Effectiveness Factors For Mth Order And Langmuir Rate Equations In Spherical Coordinates, Jianhui Hong, William C. Hecker, Thomas H. Fletcher

Faculty Publications

Char oxidation is often modeled using an mth order intrinsic reaction rate in conjunction with an effectiveness factor to account for intraparticle diffusion of gas species. This approach involves the use of a general modulus (MT) and using the first-order curve of effectiveness factor vs MT. This method was originally referred to as the general asymptotic solution. It has been suggested that a simple Langmuir rate equation is more suitable for modeling the effects of pressure on char reactivity. Therefore, several methods of developing general moduli for the Langmuir rate expression are shown. The general asymptotic …


Membrane Process For Biological Treatment Of Contaminated Gas Streams, Sarina J. Ergas, Leslee Shumway, Mark W. Fitch, Jeffrey J. Neemann May 1999

Membrane Process For Biological Treatment Of Contaminated Gas Streams, Sarina J. Ergas, Leslee Shumway, Mark W. Fitch, Jeffrey J. Neemann

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

A Hollow Fiber Membrane Bioreactor Was Investigated for Control of Air Emissions of Biodegradable Volatile Organic Compounds (VOCs). in the Membrane Bioreactor, Gases Containing VOCs Pass through the Lumen of Microporous Hydrophobic Hollow Fiber Membranes. Soluble Compounds Diffuse through the Membrane Pores and Partition into a VOC Degrading Biofilm. the Hollow Fiber Membranes Serve as a Support for the Microbial Population and Provide a Large Surface Area for VOC and Oxygen Mass Transfer. Experiments Were Performed to Investigate the Effects of Toluene Loading Rate, Gas Residence Time, and Liquid Phase Turbulence on Toluene Removal in a Laboratory-Scale Membrane Bioreactor. Initial …


Simulation Modeling Presentations: The Life Cycle, Edward Yellig, Paul Savory May 1999

Simulation Modeling Presentations: The Life Cycle, Edward Yellig, Paul Savory

Department of Industrial and Management Systems Engineering: Faculty Publications

A typical large scale simulation modeling project spans many months and encompasses activities such as problem definition, data collection, model development, experimentation, and scenario analysis. During the life cycle of a simulation project, numerous presentations are made to many different types of audiences. The purpose of these presentations will vary from seeking project approval, requesting information, discussing simulation model features, verifying the model, validating the model, presenting the experimental results, and offering model conclusions. This paper will discuss presentation techniques we used during a year-long simulation-modeling project. We will highlight techniques used for defining the purpose of each presentation, identifying …


Estimating The Usle - Soil Erodibility Factor In Developing Tropical Countries:A Case Study In Tanzania, Metthew Mulengeral Dec 1998

Estimating The Usle - Soil Erodibility Factor In Developing Tropical Countries:A Case Study In Tanzania, Metthew Mulengeral

Tanzania Journal of Engineering and Technology (TJET)

Developing countries in the tropics are facing more soil erosion problems than the developed temperate countries. These developing countries have no accurate locally applicable equation(s) for predicting soil erosion or for planning and implementation of soil conservation measures. Furthermore, These countries do not have the necessary resources to develop the soil loss prediction equation(s). Existing empirical equations like the Universal Soil Loss Equation (USLE) if modified to suit tropical conditions can be useful a tool in soil erosion control in the region for a foreseeable future. In this paper equations'for estimating the soil erodibility factor in the USLE for tropical …


Incorporating Vertical Discontinuities In Power-Bus Modeling Using A Mixed-Potential Integral Equation And Circuit Extraction Formulation, Jun Fan, Hao Shi, James L. Drewniak, Todd H. Hubing, Richard E. Dubroff, Thomas Van Doren Oct 1998

Incorporating Vertical Discontinuities In Power-Bus Modeling Using A Mixed-Potential Integral Equation And Circuit Extraction Formulation, Jun Fan, Hao Shi, James L. Drewniak, Todd H. Hubing, Richard E. Dubroff, Thomas Van Doren

Electrical and Computer Engineering Faculty Research & Creative Works

Noise on the DC power-bus attributed to device switching is among the primary sources of EMI and signal integrity problems. A mixed-potential integral equation formulation with circuit extraction approach is used to model the planar multi-layer power-bus geometry, which can also include arbitrary shaped power regions on multiple layers. Incorporating vertical discontinuities, e.g., decoupling capacitor interconnects, is a critical aspect of the modeling, and must be done properly since they are included as a lumped element model and not a part of the MPIE formulation. Agreement with experimental results demonstrate the present approach.


Comparison Of Observed And Simulated Grow-Finish Swine Performance Under Summer Conditions, Larry W. Turner, Thomas C. Bridges, Richard D. Coffey, Richard S. Gates, Gary R. Parker, Tami M. Brown-Brandl, Douglas G. Overhults Jul 1998

Comparison Of Observed And Simulated Grow-Finish Swine Performance Under Summer Conditions, Larry W. Turner, Thomas C. Bridges, Richard D. Coffey, Richard S. Gates, Gary R. Parker, Tami M. Brown-Brandl, Douglas G. Overhults

Biosystems and Agricultural Engineering Faculty Publications

As a part of a National Pork Producers Council educational program, our research and extension team at the University of Kentucky was linked with an independent commercial swine producer to test the NCPIG model against observed commercial on-farm data. This experience provided improved information for model development as well as increased producer insight into the data input needs and potential benefits of modeling. Detailed production information comparisons between the NCPIG model and producer data are presented for summer time conditions to assess the validity of the NCPIG model for simulation of grow-finish swine performance. Results demonstrated that the NCPIG model …


A Nonisothermal Nickel‐Hydrogen Cell Model, Pauline De Vidts, Javier Delgado, B. Wu, D. M. See, K. Kosanovich, Ralph E. White Jan 1998

A Nonisothermal Nickel‐Hydrogen Cell Model, Pauline De Vidts, Javier Delgado, B. Wu, D. M. See, K. Kosanovich, Ralph E. White

Faculty Publications

No abstract provided.


Disaggregation Procedures For Stochastic Hydrology Based On Nonparametric Density Estimation, David G. Tarboton, Ashish Sharma, Upmanu L. Lall Jan 1998

Disaggregation Procedures For Stochastic Hydrology Based On Nonparametric Density Estimation, David G. Tarboton, Ashish Sharma, Upmanu L. Lall

Civil and Environmental Engineering Faculty Publications

Synthetic simulation of streamflow sequences is important for the analysis of water supply reliability. Disaggregation models are an important component of the stochastic streamflow generation methodology. They provide the ability to simulate multiseason and multisite streamflow sequences that preserve statistical properties at multiple timescales or space scales. In recent papers we have suggested the use of nonparametric methods for streamflow simulation. These methods provide the capability to model time series dependence without a priori assumptions as to the probability distribution of streamflow. They remain faithful to the data and can approximate linear or nonlinear dependence. In this paper we extend …


Testing Of A Water Loss Distribution Model For Moving Sprinkler Systems, Allen L. Thompson, Derrel L. Martin, John M. Norman, Judy A. Tolk, James R. Gilley, Arlan D. Schneider Sep 1997

Testing Of A Water Loss Distribution Model For Moving Sprinkler Systems, Allen L. Thompson, Derrel L. Martin, John M. Norman, Judy A. Tolk, James R. Gilley, Arlan D. Schneider

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Field water balance measurements using monolithic lysimeters were used in validating the Cupid-DPE model for predicting water loss partitioning during sprinkler irrigation from a moving lateral system fitted with impact sprinklers and spray nozzles. The model combines equations governing water droplet evaporation and droplet ballistics with a comprehensive plant-environment energy balance model. Comparisons indicate good agreement between measured and modeled transpiration, and the measured and modeled soil evaporation during the day of irrigation. Total predicted evapotranspiration during the day of irrigation was greater than measured totals using the monolithic lysimeters. However, part of this difference was because the lysimeters could …


Accumulation Of Lead By Anabaena Cylindrica: Mathematical Modeling And An Energy Dispersive X-Ray Study, David T. Swift, Daniel Forciniti Jul 1997

Accumulation Of Lead By Anabaena Cylindrica: Mathematical Modeling And An Energy Dispersive X-Ray Study, David T. Swift, Daniel Forciniti

Chemical and Biochemical Engineering Faculty Research & Creative Works

The ability of microorganisms to selectively adsorb various heavy metal ions has been recognized for over a decade. We have investigated the biosorption of lead by an active culture of the cyanobacterium Anabaena cylindrica. Energy dispersive X-ray microanalysis was used to evaluate the different uptake mechanisms in the various subcellular regions. Three were identified; a very fast adsorption mechanism in the cell envelope; a time- dependent deposition reaction on the cell surface; and an adsorption mechanism, also time dependent, on the polyphosphate body inside the cell. Atomic absorption spectrometry was then used to quantify the changes with time of bulk …


Evaluation Of Two-Dimensional Hydraulic Modeling In A Natural River And Implications In Instream Flow Assessment Methods, Karl L. Tarbet May 1997

Evaluation Of Two-Dimensional Hydraulic Modeling In A Natural River And Implications In Instream Flow Assessment Methods, Karl L. Tarbet

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Logan River was used as a study site to assess the capabilities of two-dimensional depth-averaged hydraulic modeling in the x-y plane of a natural river for use with instream flow studies. Data were collected to spatially represent the study reach with depth, velocity, northing, easting, elevation, and substrate values using a total station and electronic velocity meter. Computational finite element meshes were generated using four different density levels of geometry data to examine the relationship between field data density and computational mesh on geometry errors. Geometry errors were found to be related to smoothing effects, which removed complex channel …