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Articles 1411 - 1440 of 3295

Full-Text Articles in Engineering

Integrated Stem Through Tumblewing Gliders, Scott R. Bartholomew Jan 2017

Integrated Stem Through Tumblewing Gliders, Scott R. Bartholomew

Faculty Publications

Teachers have the opportunity to use technology and engineering design problems to engage students in integrated STEM education. “Tumblewing” gliders are easy-to-make paper gliders that can challenge, excite, and engage students. As students emphasize the practices of science and engineering while completing a tumblewing design challenge, they will engage in both scientific inquiry and the engineering design process.

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A Well Clear Recommendation For Small Uas In High-Density, Ads-B-Enabled Airspace, Timothy Mclain, Matthew O. Duffield Jan 2017

A Well Clear Recommendation For Small Uas In High-Density, Ads-B-Enabled Airspace, Timothy Mclain, Matthew O. Duffield

Faculty Publications

With the growing popularity of small unmanned aircraft systems (UAS), there is a significant need to enable small UAS to detect and avoid collisions with both manned and unmanned aircraft. The capabilities of ADS-B make it an attractive sensor for detect and avoid (DAA), but it is susceptible to frequency congestion. This paper quantitatively analyzes the frequency limitations of 978 MHz ADS-B. It then uses these limitations to make a recommendation for well clear in ADS-B-equipped airspace that has a high density of small UAS operations.

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Hybrid Concentrated Solar Thermal Power Systems: A Review, Kody M. Powell, Khalid Rashid, Kevin Ellingwood, Jake Tuttle, Brian D. Iverson Jan 2017

Hybrid Concentrated Solar Thermal Power Systems: A Review, Kody M. Powell, Khalid Rashid, Kevin Ellingwood, Jake Tuttle, Brian D. Iverson

Faculty Publications

Concentrated solar power (CSP), or solar thermal power, is an ideal technology to hybridize with other energy technologies for power generation. CSP shares technology with conventional power generation and can be readily integrated with other energy types into a synergistic system, which has many potential benefits including increased dispatchability and reliability, improved efficiency, reduced capital costs through equipment sharing, and the opportunity for flexible operation by alternating between energy sources. Another advantage of CSP technology is the ability to readily store via thermal energy storage (TES), making the intermittent solar resource dispatchable. A review of CSP hybridization strategies with coal, …

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Performance Verification For Robot Missions In Uncertain Environments, Damian Lyons, Ron Arkin, Shu Jiang, Matt O'Brien, Feng Tang, Peng Tang Jan 2017

Performance Verification For Robot Missions In Uncertain Environments, Damian Lyons, Ron Arkin, Shu Jiang, Matt O'Brien, Feng Tang, Peng Tang

Faculty Publications

Abstract—Certain robot missions need to perform predictably in a physical environment that may have significant uncertainty. One approach is to leverage automatic software verification techniques to establish a performance guarantee. The addition of an environment model and uncertainty in both program and environment, however, means the state-space of a model-checking solution to the problem can be prohibitively large. An approach based on behavior-based controllers in a process-algebra framework that avoids state-space combinatorics is presented here. In this approach, verification of the robot program in the uncertain environment is reduced to a filtering problem for a Bayesian Network. Validation results …

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A Summer Camp In Engineering Physics For Incoming Freshman To Improve Retention And Student Success, Hector A. Ochoa, Christopher J. Aul, Dan Bruton, Collin J. Timmons Jan 2017

A Summer Camp In Engineering Physics For Incoming Freshman To Improve Retention And Student Success, Hector A. Ochoa, Christopher J. Aul, Dan Bruton, Collin J. Timmons

Faculty Publications

Summer camps have proven to be a valuable tool to attract and recruit students interested in pursuing a career in the STEM field. They have been also used to spark their curiosity in areas like mathematics. However, these camps do not help with issues that appear after the student has been admitted at the university. It is well known that many students are shocked when they transition from high-school to college. Many of them do not know how to handle their academic freedom; they start without any friends, and they do not know the campus and the resources available. By …

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Establishing A-Priori Performance Guarantees For Robot Missions That Include Localization Software, Damian Lyons, Ron Arkin, Shu Jiang, Matt O'Brien, Feng Tang, Peng Tang Jan 2017

Establishing A-Priori Performance Guarantees For Robot Missions That Include Localization Software, Damian Lyons, Ron Arkin, Shu Jiang, Matt O'Brien, Feng Tang, Peng Tang

Faculty Publications

One approach to determining whether an automated system is performing correctly is to monitor its performance, signaling when the performance is not acceptable; another approach is to automatically analyze the possible behaviors of the system a-priori and determine performance guarantees. Thea authors have applied this second approach to automatically derive performance guarantees for behaviorbased, multi-robot critical mission software using an innovative approach to formal verification for robotic software. Localization and mapping algorithms can allow a robot to navigate well in an unknown environment. However, whether such algorithms enhance any specific robot mission is currently a matter for empirical validation. Several …

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Impact Of Reviewer Social Interaction On Online Consumer Review Fraud Detection, Kunal Goswami, Younghee Park, Chungsik Song Jan 2017

Impact Of Reviewer Social Interaction On Online Consumer Review Fraud Detection, Kunal Goswami, Younghee Park, Chungsik Song

Faculty Publications

Background Online consumer reviews have become a baseline for new consumers to try out a business or a new product. The reviews provide a quick look into the application and experience of the business/product and market it to new customers. However, some businesses or reviewers use these reviews to spread fake information about the business/product. The fake information can be used to promote a relatively average product/business or can be used to malign their competition. This activity is known as reviewer fraud or opinion spam. The paper proposes a feature set, capturing the user social interaction behavior to identify fraud. …

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Optimal Trajectory Determination And Mission Design For Asteroid/Deep-Space Exploration Via Multibody Gravity Assist Maneuvers, Sean Fritz, Kamran Turkoglu Jan 2017

Optimal Trajectory Determination And Mission Design For Asteroid/Deep-Space Exploration Via Multibody Gravity Assist Maneuvers, Sean Fritz, Kamran Turkoglu

Faculty Publications

This paper discusses the creation of a genetic algorithm to locate and optimize interplanetary trajectories using gravity assist maneuvers to improve fuel efficiency of the mission. The algorithm is implemented on two cases: (i) a Centaur-class target close to the ecliptic plane and (ii) a Centaur-class target with a high inclination to the ecliptic plane. Cases for multiple numbers of flybys (up to three) are discussed and compared. It is shown that, for the targets considered here, a single flyby of Jupiter is the most efficient trajectory to either target with the conditions and limitations discussed in this paper. In …

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Enhancing Ductility Of Wwr Slabs, Mohamed Shwani, Taylor J. Sorensen, Ethan Pickett, Parker Syndergaard, Marc Maguire Jan 2017

Enhancing Ductility Of Wwr Slabs, Mohamed Shwani, Taylor J. Sorensen, Ethan Pickett, Parker Syndergaard, Marc Maguire

Faculty Publications

A series of research studies have recently identified an issue called strain localization in welded wire reinforced (WWR) members. This phenomenon reportedly concentrates strains at welded cross wire locations and severely limit ductility. Those that identified the phenomenon used it to imply that WWR is unsafe because it does not warn of failure. This research program is investigating details to mitigate the strain localization effect and demonstrate the WWR can be used safely. Sixteen beams have been constructed using WWR and rebar with various cross wire spacing, using a realistic design. The strain localization phenomenon was not demonstrated, but WWR …

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Improving Sensitivity Of Electrochemical Sensors With Convective Transport In Free-Standing, Carbon Nanotube Structures, Benjamin J. Brownlee, Kevin M. Marr, Jonathan C. Claussen, Brian D. Iverson Jan 2017

Improving Sensitivity Of Electrochemical Sensors With Convective Transport In Free-Standing, Carbon Nanotube Structures, Benjamin J. Brownlee, Kevin M. Marr, Jonathan C. Claussen, Brian D. Iverson

Faculty Publications

High-aspect-ratio, porous membrane of vertically-aligned carbon nanotubes (CNTs) were developed through a templated microfabrication approach for electrochemical sensing. Nanostructured platinum (Pt) catalyst was deposited onto the CNTs with a facile, electroless deposition method, resulting in a Pt-nanowire-coated, CNT sensor (PN-CNT). Convection mass transfer enhancement was shown to improve PN-CNT sensor performance in the non-enzymatic, amperometric sensing of hydrogen peroxide (H2O2). In particular, convective enhancement was achieved through the use of high surface area to fluid volume structures and concentration boundary layer confinement in a channel. Stir speed and sensor orientation especially influenced the measured current in …

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Gradient-Based Optimization Of Wind Farms With Different Turbine Heights, Andrew P.J. Stanley, Jared Thomas, Andrew Ning, Jennifer Annoni, Katherine Dykes, Paul Fleming Jan 2017

Gradient-Based Optimization Of Wind Farms With Different Turbine Heights, Andrew P.J. Stanley, Jared Thomas, Andrew Ning, Jennifer Annoni, Katherine Dykes, Paul Fleming

Faculty Publications

Turbine wakes reduce power production in a wind farm. Current wind farms are gen- erally built with turbines that are all the same height, but if wind farms included turbines with different tower heights, the cost of energy (COE) may be reduced. We used gradient-based optimization to demonstrate a method to optimize wind farms with varied hub heights. Our study includes a modified version of the FLORIS wake model that accommodates three-dimensional wakes integrated with a tower structural model. Our purpose was to design a process to minimize the COE of a wind farm through layout optimization and varying turbine …

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Optimal Combined Long-Term Facility Design And Short-Term Operational Strategy For Chp Capacity Investments, Jose Mojica, Damon Petersen, Brigham Hansen, Kody Powell, John Hedengren Jan 2017

Optimal Combined Long-Term Facility Design And Short-Term Operational Strategy For Chp Capacity Investments, Jose Mojica, Damon Petersen, Brigham Hansen, Kody Powell, John Hedengren

Faculty Publications

This work presents a detailed case study for the optimization of the expansion of a district energy system evaluating the investment decision timing, type of capacity expansion, and fine-scale operational modes. The study develops an optimization framework to find the investment schedule over 30 years with options of investing in traditional heating sources (boilers) or a next-generation combined heat and power (CHP) plant that provides heat and electricity. In district energy systems, the selected capacity and type of system is dependent on demand-side requirements, energy prices, and environmental costs. This work formulates capacity planning over a time horizon as a …

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Modeling Effects Of Annealing On Coal Char Reactivity To O2 And Co2, Based On Preparation Conditions, Troy Michael Holland, Sham Bhat, Peter Marcy, James Gattiker, Joel D. Kress, Thomas H. Fletcher Jan 2017

Modeling Effects Of Annealing On Coal Char Reactivity To O2 And Co2, Based On Preparation Conditions, Troy Michael Holland, Sham Bhat, Peter Marcy, James Gattiker, Joel D. Kress, Thomas H. Fletcher

Faculty Publications

Oxy-fired coal combustion is a promising potential carbon capture technology. Predictive computational fluid dynamics (CFD) simulations are valuable tools in evaluating and deploying oxyfuel and other carbon capture technologies, either as retrofit technologies or for new construction. However, accurate predictive combustor simulations require physically realistic submodels with low computational requirements. A recent sensitivity analysis of a detailed char conversion model (Char Conversion Kinetics (CCK)) found thermal annealing to be an extremely sensitive submodel. In the present work, further analysis of the previous annealing model revealed significant disagreement with numerous datasets from experiments performed after that annealing model was developed. The …

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Comprehensive Model Of Single Particle Pulverized Coal Combustion Extended To Oxy-Coal Conditions, Troy Michael Holland, Thomas H. Fletcher Jan 2017

Comprehensive Model Of Single Particle Pulverized Coal Combustion Extended To Oxy-Coal Conditions, Troy Michael Holland, Thomas H. Fletcher

Faculty Publications

Oxy-fired coal combustion is a promising potential carbon capture technology. Predictive CFD simulations are valuable tools in evaluating and deploying oxy-fuel and other carbon capture technologies either as retrofit technologies or for new construction. However, accurate predictive simulations require physically realistic submodels with low computational requirements. In particular, comprehensive char oxidation and gasification models have been developed that describe multiple reaction and diffusion processes. This work extends a comprehensive char conversion code (CCK), which treats surface oxidation and gasification reactions as well as processes such as film diffusion, pore diffusion, ash encapsulation, and annealing. In this work several submodels in …

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Semi-Empirical Model For Fire Spread In Shrubs With Spatially-Defined Fuel Elements And Flames, Dallan Prince, Chen Shen, Thomas H. Fletcher Jan 2017

Semi-Empirical Model For Fire Spread In Shrubs With Spatially-Defined Fuel Elements And Flames, Dallan Prince, Chen Shen, Thomas H. Fletcher

Faculty Publications

A semi-empirical model was developed which forms shrub geometries from distinct fuel elements (e.g. leaves) and describes flame spread from element to element. Ignition, flame growth and flame decay patterns were based on combustion data of single leaves. Extension of the model to various heating conditions was achieved by scaling the flame growth parameters using physics-based heat transfer models. The resulting model offers a novel approach to examine fire spread and to explicitly describe both distinct fuel elements and fire behavior. This approach balances computational speed and modeling detail while providing a unique perspective into fire spread phenomena. Comparisons of …

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Robust And Agile System Against Fault And Anomaly Traffic In Software Defined Networks, Mihui Kim, Younghee Park, Rohit Kotalwar Jan 2017

Robust And Agile System Against Fault And Anomaly Traffic In Software Defined Networks, Mihui Kim, Younghee Park, Rohit Kotalwar

Faculty Publications

The main advantage of software defined networking (SDN) is that it allows intelligent control and management of networking though programmability in real time. It enables efficient utilization of network resources through traffic engineering, and offers potential attack defense methods when abnormalities arise. However, previous studies have only identified individual solutions for respective problems, instead of finding a more global solution in real time that is capable of addressing multiple situations in network status. To cover diverse network conditions, this paper presents a comprehensive reactive system for simultaneously monitoring failures, anomalies, and attacks for high availability and reliability. We design three …

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Developing A General Methodology For Evaluating Composite Action In Insulated Wall Panels, Taylor Sorensen Jan 2017

Developing A General Methodology For Evaluating Composite Action In Insulated Wall Panels, Taylor Sorensen

Faculty Publications

Precast concrete sandwich wall panels (PCSWPs) have been in use for over 60 years. They provide a very efficient building envelope for many buildings. Characteristic PCSWPs comprise an outer and inner layer (or wythe) of concrete separated by an insulating material. To use all of the material as efficiently as possible, the layers are attached by connectors which penetrate through the insulating layer and are embedded in either concrete wythe. These connectors make it possible for both layers of the wall to work together when resisting loads. The connectors are made out of plastic, or FRP, to prevent heat transfer …

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Extending The Upper Temperature Range Of Microchip Gas Chromatography Using A Heater/Clamp Assembly, Abhijit Ghosh, Jacob E. Johnson, Johnathan G. Nuss, Brittany A. Stark, Aaron R. Hawkins, Luke T. Tolley, Brian D. Iverson, H. Dennis Tolley, Milton L. Lee Jan 2017

Extending The Upper Temperature Range Of Microchip Gas Chromatography Using A Heater/Clamp Assembly, Abhijit Ghosh, Jacob E. Johnson, Johnathan G. Nuss, Brittany A. Stark, Aaron R. Hawkins, Luke T. Tolley, Brian D. Iverson, H. Dennis Tolley, Milton L. Lee

Faculty Publications

Miniaturization of gas chromatography (GC) instrumentation is of interest because it addresses current and future issues relating to compactness, portability and field application. While incremental advancements continue to be reported in microchip GC, the current performance is far from acceptable. This lower performance compared to conventional GC is due to factors such as pooling of the stationary phase in corners of non-cylindrical channels, adsorption of sensitive compounds on incompletely deactivated surfaces, shorter column lengths and less than optimum interfacing to injector and detector. In this work, a microchip GC system was developed that solves the latter challenge, i.e. microchip interfacing …

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Controlled Manipulation Of Floating Objects On Deformed Fluid Interfaces And Conditions For Stable Equilibria, Jose M. Carballo, Qi Ni, Jose Vasquez, Nathan B. Crane Jan 2017

Controlled Manipulation Of Floating Objects On Deformed Fluid Interfaces And Conditions For Stable Equilibria, Jose M. Carballo, Qi Ni, Jose Vasquez, Nathan B. Crane

Faculty Publications

At the millimeter scale, interactions between floating and semi-immersed objects are significant. The local curvature of the interface is modified by the weight/buoyancy forces of floating objects, and by the surface properties of semi-immersed objects. The curvature changes generate attractive (or repulsive) interactions between floating parts, and semi-immersed objects. This work demonstrates how electrowetting can manipulate these interactions in order to position, align, assemble and transport parts attached to the fluid interface. This demonstrates one way in which fluid interfaces can provide an alternative to standard pick and place technology for part positioning/assembly. Typically, the part/rod forces are purely attractive …

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Investigating Composite Action At Ultimate For Commercial Sandwich Panel Composite Connectors, Salam Al-Rubaye, Taylor J. Sorensen, Marc Maguire Jan 2017

Investigating Composite Action At Ultimate For Commercial Sandwich Panel Composite Connectors, Salam Al-Rubaye, Taylor J. Sorensen, Marc Maguire

Faculty Publications

To achieve full or partial-composite action in prestressed concrete sandwich panel walls, the engineer must obtain a percent composite action from a connector manufacturer, making some engineers uncomfortable. Engineers are dependent upon the recommendations given by the connector manufacturers to establish their designs. This project tested six full-scale sandwich panel walls to evaluate the percent composite action of various connectors and compare the results to those provided by the composite connector manufacturers. This study concluded that the reported degrees of composite action from each manufacturer are considered conservative in all instances for the connectors tested in this paper. Additionally, the …

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Middle School Student Habits, Perceptions, And Self-Directed Learning, Scott R. Bartholomew Jan 2017

Middle School Student Habits, Perceptions, And Self-Directed Learning, Scott R. Bartholomew

Faculty Publications

Today’s students are growing up in a digital world with constant connectivity, instant access to information, and new technological developments at every turn. The feasibility, effectiveness, and possibilities of students leveraging technological tools around them for learning are the subject of continual debate (Becker, 2017; Bowen, 2012; Tamim, Bernard, Borokhovski, Abrami, & Schmid, 2011). In this study, 706 middle school students from 18 classes worked in groups of 2-3 to complete an open-ended engineering design challenge. Students completed design portfolios and constructed prototypes in their groups in response to the design challenge. Classes were divided with some receiving access to …

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Eliminating The Illusion Of Learning From Engineering Courses, Jason Weaver Jan 2017

Eliminating The Illusion Of Learning From Engineering Courses, Jason Weaver

Faculty Publications

This paper describes the efforts of the author to incorporate tools into an undergraduate engineering course to help facilitate better learning and assess proficiency more effectively by avoiding the illusion of learning. Several techniques are used, including suggestions from the recent book Make It Stick by Brown, Roediger, and McDaniel. Student feedback and instructor observations are discussed, and future recommendations for the course are given

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Fundamental Principles Of Tremor Propagation In The Upper Limb, Andrew D. Davidson, Steven Knight Charles Jan 2017

Fundamental Principles Of Tremor Propagation In The Upper Limb, Andrew D. Davidson, Steven Knight Charles

Faculty Publications

Although tremor is the most common movement disorder, there exist few effective tremor-suppressing devices, in part because the characteristics of tremor throughout the upper limb are unknown. To clarify, optimally suppressing tremor requires a knowledge of the mechanical origin, propagation, and distribution of tremor throughout the upper limb. Here we present the first systematic investigation of how tremor propagates between the shoulder, elbow, forearm, and wrist. We simulated tremor propagation using a linear, time-invariant, lumped-parameter model relating joint torques and the resulting joint displacements. The model focused on the seven main degrees of freedom from the shoulder to the wrist …

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Modeling Soot Oxidation And Gasification With Bayesian Statistics, Alexander Jon Josephson, Neal D. Gaffin, Sean T. Smith, Thomas H. Fletcher, David Lignell Jan 2017

Modeling Soot Oxidation And Gasification With Bayesian Statistics, Alexander Jon Josephson, Neal D. Gaffin, Sean T. Smith, Thomas H. Fletcher, David Lignell

Faculty Publications

This paper presents a statistical method for model calibration using data collected from literature. The method is used to calibrate parameters for global models of soot consumption in combustion systems. This consumption is broken into two different submodels: first for oxidation where soot particles are attacked by certain oxidizing agents; second for gasification where soot particles are attacked by H2O or CO2 molecules. Rate data were collected from 19 studies in the literature and evaluated using Bayesian statistics to calibrate the model parameters. Bayesian statistics are valued in their ability to quantify uncertainty in modeling. The calibrated consumption model with …

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Model For The Evolution Of Pore Structure In A Lignite Particle During Pyrolysis. 2. Influence Of Cross-Linking Reactions, Molten Metaplast, And Molten Ash On Particle Surface Area, He Yang, Thomas H. Fletcher, Sufen Li, Haoquan Hu, Lijun Li Jan 2017

Model For The Evolution Of Pore Structure In A Lignite Particle During Pyrolysis. 2. Influence Of Cross-Linking Reactions, Molten Metaplast, And Molten Ash On Particle Surface Area, He Yang, Thomas H. Fletcher, Sufen Li, Haoquan Hu, Lijun Li

Faculty Publications

A model for the evolution of the pore structure in a lignite particle during pyrolysis was established previously based on the chemical percolation devolatilization (CPD) model, using coal polymer network parameters to calculate the surface area and porosity of the particle. In this paper, to get the accurate surface area of coal particle at high pyrolysis temperature, the previous model was improved by considering the effects of cross-linking reactions, molten Metaplast, and ash. The good agreement of the predicted surface area with experiments at temperature below 1200 K in the previous model is maintained, and model accuracy is improved at …

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Study Potential Of Indigenous Pseudomonas Aeruginosa And Bacillus Subtilis In Bioremediation Of Diesel-Contaminated Water, Mohammad-Saeed Safdari, Hamid-Reza Kariminia, Zahra Ghobadi Nejad, Thomas H. Fletcher Jan 2017

Study Potential Of Indigenous Pseudomonas Aeruginosa And Bacillus Subtilis In Bioremediation Of Diesel-Contaminated Water, Mohammad-Saeed Safdari, Hamid-Reza Kariminia, Zahra Ghobadi Nejad, Thomas H. Fletcher

Faculty Publications

Petroleum products which are used in a wide variety of industries as energy sources and raw materials have become a major concern in pollution of terrestrial and marine environments. The purpose of this study was to assess the potential of indigenous microbial isolates for degradation of diesel fuel. Two most proficient bacterial strains among five isolated strains from polluted soil of an industrial refinery were studied. The isolates then were identified as Pseudomonas aeruginosa and Bacillus subtilis using biochemical tests and 16S rRNA gene sequence analyses. P. aeruginosa showed higher biodegradation efficiency than B. subtilis in shaking flask containing diesel-contaminated …

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Global Command And Control For The Future Operating Concept: Implications For Structural Design And Information, Ian M. Slazinik, Benjamin T. Hazen Jan 2017

Global Command And Control For The Future Operating Concept: Implications For Structural Design And Information, Ian M. Slazinik, Benjamin T. Hazen

Faculty Publications

Due to increasing demands on air mobility aircraft, US Transportation Command(USTRANSCOM) has more recently advocated retaining operational control (OPCON)of aircraft it might have transferred to a requesting combatant command in the past. This recent approach mirrors that of similar-type civilian logistics operations that are centrally managed to maximize efficiencies by flowing resources to the point of need without having to navigate through time-consuming sourcing processes. Furthermore, the acceleration of information availability has condensed decision timelines and changed how similar civilian organizations organize and perform, allowing them to react seemingly on a dime to changing market conditions anywhere.4While retaining OPCON might …

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Developments In Capture- Γ Libraries For Nonproliferation Applications, A. M. Hurst, R. B. Firestone, B. W. Sleaford, D. L. Bleuel, M. S. Basunia, F. Becvar, T. Belgya, L. A. Bernstein, J. J. Carroll, B. Detwiler, J. E. Escher, C. Genreith, B. L. Goldblum, M. Krticka, A. G. Lerch, David A. Matters, John W. Mcclory, Stephen R. Mchale, Zs. Revay, L. Szentmiklosi, D. Turkoglu, A. Ureche, J. Vulic Jan 2017

Developments In Capture- Γ Libraries For Nonproliferation Applications, A. M. Hurst, R. B. Firestone, B. W. Sleaford, D. L. Bleuel, M. S. Basunia, F. Becvar, T. Belgya, L. A. Bernstein, J. J. Carroll, B. Detwiler, J. E. Escher, C. Genreith, B. L. Goldblum, M. Krticka, A. G. Lerch, David A. Matters, John W. Mcclory, Stephen R. Mchale, Zs. Revay, L. Szentmiklosi, D. Turkoglu, A. Ureche, J. Vulic

Faculty Publications

The neutron-capture reaction is fundamental for identifying and analyzing the γ-ray spectrum from an unknown assembly because it provides unambiguous information on the neutron-absorbing isotopes. Nondestructive-assay applications may exploit this phenomenon passively, for example, in the presence of spontaneous-fission neutrons, or actively where an external neutron source is used as a probe. There are known gaps in the Evaluated Nuclear Data File libraries corresponding to neutron-capture γ-ray data that otherwise limit transport-modeling applications. In this work, we describe how new thermal neutron-capture data are being used to improve information in the neutron-data libraries for isotopes relevant to nonproliferation applications. We …

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Evolutionary View Planning For Optimized Uav Terrain Modeling In A Simulated Environment, Ronald A. Martin, Ivan Rojas, Kevin W. Franke, John Hedengren Dec 2016

Evolutionary View Planning For Optimized Uav Terrain Modeling In A Simulated Environment, Ronald A. Martin, Ivan Rojas, Kevin W. Franke, John Hedengren

Faculty Publications

This work demonstrates the use of genetic algorithms in optimized view planning for 3D reconstruction applications using small unmanned aerial vehicles (UAVs). The quality of UAV site models is currently highly dependent on manual pilot operations or grid-based automation solutions. When applied to 3D structures, these approaches can result in gaps in the total coverage or inconsistency in final model resolution. Genetic algorithms can effectively explore the search space to locate image positions that produce high quality models in terms of coverage and accuracy. A fitness function is defined, and optimization parameters are selected through semi-exhaustive search. A novel simulation …

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Generation Of Vector Partially Coherent Optical Sources Using Phase-Only Spatial Light Modulators, Milo W. Hyde Iv, Santasri Bose-Pillai, David G. Voelz, Xifeng Xiao Dec 2016

Generation Of Vector Partially Coherent Optical Sources Using Phase-Only Spatial Light Modulators, Milo W. Hyde Iv, Santasri Bose-Pillai, David G. Voelz, Xifeng Xiao

Faculty Publications

A simple and flexible optical system for generating electromagnetic or vector partially coherent sources or beams is presented. The alternative design controls field amplitude (beam shape), coherence, and polarization using only spatial light modulators. This improvement makes the apparatus simpler to construct and significantly increases the flexibility of vector partially coherent source generators by allowing many different types of sources to be produced without changing the physical setup. The system’s layout and theoretical foundations are thoroughly discussed. The utility and flexibility of the proposed system are demonstrated by producing a vector Schell-model and non-Schell-model source. The experimental results are compared …

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