Engineering Commons^™

Establishment Of A System Operating Characteristic For Autonomous Wide Area Search Vehicles, Brian A. Kish

Theses and Dissertations

The optimal employment of autonomous search and destroy vehicles is addressed. The results apply to air, land, or water vehicles with 1, k, or infinite warheads. The specific scenarios considered involve an air vehicle searching a battle space for stationary targets in the presence of false targets. Encounters are modeled with uniform, Poisson, and normal distributions. Linear and circular search patterns are examined. All relevant parameters are extracted from intelligence information, the sensor performance specification, and the air vehicle performance specification. Analytic system effectiveness measures are derived using applied probability theory. The effectiveness measures derived in this dissertation handle time-varying …

Characterization Of The Global Hawk Low Pressure Turbine First Rotor, Timothy L. Garmoe

Theses and Dissertations

The Air Force Research Laboratory, Propulsion Directorate at Wright Patterson Air Force Base has studied the performance of turbine blade geometries utilizing a large scale, low speed, drawdown wind tunnel in an effort to better understand gas turbine blade aerodynamics. Currently, the Air Force's Unmanned Aerial Vehicle (UAV) Global Hawk has been operated primarily at flight conditions other than the design point of its Allison AE3007H turbofan engine. This off design condition decreased the Reynolds number at the low pressure turbine causing losses in efficiency and loading. Two different blades were studied to maximize performance of the Global Hawk turbine. …

Experimental Investigation Of A Lift Augmented Ground Effect Platform, Roberto T. Igue

Theses and Dissertations

This experimental study investigated the feasibility of applying the concept of a skirtless hovercraft into the production of an operational vehicle. A 0.255 m diameter prototype was designed, built and tested. An air bearing table was used as a testing platform, virtually eliminating the influence of friction and providing one degree of freedom for the experiments. Static tests were performed at various heights and craft configurations, providing a wide range of data for comparison. Lift, torque and efficiency were measured and calculated for each setting. Pressure and velocity information was also collected at specific points around the craft when operating …

Effects Of Boundary Layer Flow Control Using Plasma Actuator Discharges, Jeffrey M. Newcamp

Theses and Dissertations

This study addresses the usage and effects of atmospheric plasma discharges on the near wall flow conditions for a Pak-B low-pressure turbine blade. A plasma actuator was built normal to the freestream flow in a low-speed wind tunnel. The test section of the wind tunnel had a contoured upper wall geometry designed to mimic the suction side of a Pak-B turbine blade. A high frequency ac voltage source supplied three voltages in the kilovolt range at four Reynolds numbers in the experiment, between 10,000 and 103,000. The effect of the plasma on the near-wall boundary layer conditions was evaluated at …

The Effect Of Aerodynamic Surfaces Versus Thrust Maneuvers On Reentry Vehicles, Meredith M. Albrecht

Theses and Dissertations

This research effort analyzes the effect of aerodynamic surfaces versus thrust maneuvers on a reentry vehicle. At high altitudes the effect of aerodynamic surfaces on the reentry vehicle is small due to low atmospheric density; however as the vehicle reaches lower altitudes a lift maneuver is very successful in deflecting the vehicle and creating a large impact footprint. When a continuous thrust maneuver is input in the place of a lift maneuver the results are very similar at the highest maneuver altitudes, although the impact footprint shrinks rapidly as the maneuver altitude decreases. Additionally, when the thrust maneuver is along …

Superdirectivity In Mimo Systems, Michael A. Jensen, Matthew L. Morris, Jon W. Wallace

Faculty Publications

Multiantenna systems such as devices for multiple-input-multiple-output (MIMO) communication can theoretically use array superdirectivity to optimally exploit the propagation channel. In traditional analyses of MIMO systems, such superdirectivity is not observed due to the commonly applied constraint that limits the excitation current magnitudes. However, when an electromagnetically appropriate constraint on the power radiated by the array is applied, the computed capacity can include effects of transmit superdirectivity. A similar result occurs at the receiver for spatially colored noise. This paper formulates the MIMO system capacity under these circumstances and provides a framework for computing this capacity when the level of …

Branching In Electrospinning Of Nanofibers, A. L. Yarin, W. Kataphinan, Darrell Hyson Reneker

College of Polymer Science and Polymer Engineering

Electrospinning of polymer nanofibers often begins with a single, straight, elongating, and electrified fluid jet that emanates from a droplet tip when the electric field at the surface is high enough. After some distance an electrically driven bending instability of the elongating jet occurs. For a polymer solution suitable for electrospinning, capillary instability does not cause the jet to become a spray of droplets. Under some conditions, a sequence of secondary jet branches emanates from the primary jet. This paper describes an experiment in which many closely spaced branches along the jet were observed during the electrospinning of a polycaprolactone …

Adsorption Of Lactic Acid From Fermentation Broth And Aqueous Solutions On Zeolite Molecular Sieves, Isam H. Aljundi, Joanne M. Belovich, Orhan Talu

Chemical & Biomedical Engineering Faculty Publications

The recovery of lactic acid from fermentation broth and aqueous solutions was studied by adsorption on Silicalite molecular sieves. Batch experiments were used to measure the adsorption isotherms of the lactic acid on Silicalite. A linear correlation was found for both solutions. Silicalite showed a higher adsorptive capacity in the case of the aqueous solution than that of the fermentation broth. Henry’s constants were estimated as Formula Not Shown and Formula Not Shown for the aqueous and broth solutions, respectively. The effect of temperature on adsorption was also studied in batch mode. Henry’s constant dependency on …

Enterprise Strategy Development: A Three-Dimensional Approach To The Role Of Scm, Edward Sweeney, Ciaran Finn

Practitioner Journals

The Irish economy has grown strongly in recent years. This, combined with other factors in the international trading environment, has sharpened the focus on the need for innovative strategies at a national level which can contribute positively from an enterprise strategy development perspective. As traditional manufacturing activity has migrated to lower labour cost economies questions have been raised concerning the role of supply chain management (SCM) in the evolving Irish business environment. This article describes some of the main drivers in terms of both SCM and the changing economic and business environment. It goes on to propose a three-dimensional approach …

Lextran Support Project: Strategic Planning Support For Lextran Visioning, Lenahan O'Connell, Ted Grossardt

Kentucky Transportation Center Research Report

In October 2003, LexTran, the City of Lexington’s public transportation provider, was undergoing a management transition. It sought the assistance of the Kentucky Transportation Center for strategic planning and visioning. This project produced four deliverables: (1) a series of public meetings facilitated by the Kentucky Transportation Center on rider and other stakeholder attitudes toward LexTran and its general performance; (2) an environmental scan comparing LexTran to similar transit providers on operating efficiency, ridership, funding sources, and other characteristics; (3) A GIS database containing census data and other information useable for the analysis of proposed routes; and (4) a PowerPoint presentation …

Statewide Planning Scenario Synthesis: Transportation Congestion Measurement And Management, Doug Kreis, Brian Howell, Lenahan O'Connell

Kentucky Transportation Center Research Report

This study is a review of current practices in 13 states to: (1) measure traffic congestion and its costs; and (2) manage congestion with programs and techniques that do not involve the building of new highway capacity. In regard to the measures of congestion, the findings suggest two broad conclusions: (a) the most popular measures are not LOS or volume to capacity ratios; but rather the direct measures of either average time to traverse the distance between two points, or the average speed of vehicles. These are sometimes used to construct estimates of delay during peak traffic periods. (b) Five …

Corrosion Evaluation Of Mechanically Stabilized Earth Walls, Tony L. Beckham, Liecheng Sun, Tommy C. Hopkins

Kentucky Transportation Center Research Report

Numerous reinforced walls and slopes have been built over the past four decades in Kentucky, the United States, as well as worldwide. Tensile elements used in constructing low-cost reinforcing walls and slopes consist of metal polymer strips or grids. Although reinforced structures have been used extensively, the effects of corrosion on the metal tensile elements are unknown. Mechanically stabilized earth walls are expected to remain stable for many decades. An examination of the effects of corrosion of metal tensile elements used to construct these walls can provide invaluable data regarding the longevity of reinforced walls and slopes. Four mechanically stabilized …

Contrast-Detail Analysis Characterizing Diffuse Optical Fluorescence Tomography Image Reconstruction, Scott C. Davis, Brian W. Pogue, Hamid Dehghani, Keith D. Paulsen

Dartmouth Scholarship

Contrast-detail analysis is used to evaluate the imaging performance of diffuse optical fluorescence tomography (DOFT), characterizing spatial resolution limits, signal-to-noise limits, and the trade-off between object contrast and size. Reconstructed images of fluorescence yield from simulated noisy data were used to determine the contrast-to-noise ratio (CNR). A threshold of CNR=3 was used to approximate a lowest acceptable noise level in the image, as a surrogate measure for human detection of objects. For objects 0.5 cm inside the edge of a simulated tissue region, the smallest diameter that met this criteria was approximately 1.7 mm, regardless of contrast level, and test …

Development Of Modulus-To-Temperature Relations For Hma Mixtures In Wisconsin, James Crovetti, Kathleen T. Hall, R. Christopher Williams

Transportation Reports with the Wisconsin Department of Transportation

This report presents the findings of a research study conducted to develop modulus-to-temperature relations for HMA mixtures used in Wisconsin. Surface deflection data gathered from in-place HMA pavements was used to estimate the resilient modulus of the HMA layer at the various test temperatures. Laboratory resilient modulus testing was also conducted on recovered HMA cores to establish trends of HMA resilient modulus as a function of test temperature and load frequency. Prediction equations for estimating modulus-to-temperature trends were developed from laboratory testing to account for mixture-specific parameters, including fines content, air voids and binder content.

Estimations of HMA modulus-to-temperature trends …

Development Of Rational Overlay Design Procedures For Flexible Pavements, James Crovetti

Transportation Reports with the Wisconsin Department of Transportation

This report presents the findings of a research study conducted to develop procedures for the design of structural HMA overlays over existing flexible pavements in Wisconsin. The recommended procedures are presented in a hierarchal approach to allow the user the flexibility of estimating the effective structural number of an in-place HMA pavement based on visual and/or nondestructive deflection testing data and to develop overlay thickness requirements based on the structural deficiency approach.

Techniques for estimating the effective structural number of an existing pavement based on surface deflection are presented. The equations presented in the 1993 AASHTO Design Guide were modified …

Review Of Multiple Input Dc-Dc Converters For Electric And Hybrid Vehicles, Krishna P. Yalamanchili, Mehdi Ferdowsi

Electrical and Computer Engineering Faculty Research & Creative Works

Batteries, ultra capacitors, fuel cells, and solar arrays are widely used in electric and hybrid vehicles (EVs/HVs) as an electric power source or an energy storage unit. In the structure of the electric power system of modern EVs/HVs, more than one of these units may be employed to improve the performance and efficiency; hence utilization of a multi-input DC-DC converter is inevitable to obtain a regulated bus DC voltage. In this paper, a review of multiple input DC-DC power electronic converters (MI-PEC) devoted to combine the power flow from several on-board energy sources of an EV/HV is presented. Several multi-input …

Investigating Binder Flushing Of Sp-2 Mixes, Magdy A. Abdelrahman

Nebraska Department of Transportation: Research Reports

No abstract provided.

Laser And Led Effects On The Proliferation Rate Of Periodontal Ligament Fibroblasts, Allen J. Job

Loma Linda University Electronic Theses, Dissertations & Projects

PURPOSE: To compare the effectiveness of a Gallium Aluminum Arsenide (GaAlAs) diode laser and a light emitting diode (LED) on periodontal ligament fibroblast cell proliferative rates.

METHODS and MATERIALS: PDLF obtained from freshly extracted permanent teeth were cultured under standard conditions until a subconfluent monolayer was present. The next section took 5 days to complete. On day 1, the initial cell concentration of 700 uL/cm² was plated on 96-well assay plates and placed in a CO₂ incubator at 37° C for 24 hours. On day 2, cell counts were first verified using hemocytometry then were irradiated using an …

Exfoliated Graphite Nanofibers For Hydrogen Storage, Angela D. Lueking, Ling Pan, Deepa L. Narayanan, Caroline E. Burgess Clifford

Chemical and Biochemical Engineering Faculty Research & Creative Works

Exfoliation of graphite nanofibers (GNF) expands the interplanar spacing of the GNF, which leads to increased hydrogen storage. Hydrogen uptake measurements at 20 bar indicated that the overall hydrogen uptake and operative adsorption temperature are sensitive to the structural variations and graphitic spacing. The increased surface area of the EGNF-1000 led to a 1.2% hydrogen uptake at 77 K and 20 bar, a three-fold increase in hydrogen physisorption of the starting material. These results suggested that selective exfoliation of a nanofiber is a means by which to control the relative binding energy of the hydrogen interaction with the carbon structure …

Review Of Digital Control Techniques For Automotive Dc-Dc Converters, Dwaraka S. Padimiti, Mehdi Ferdowsi

Electrical and Computer Engineering Faculty Research & Creative Works

Electric and hybrid electric vehicles need a power plant that includes dc-dc converters. While using these converters, their control plays an important role in the overall performance of the vehicle. Due to their several drawbacks including poor communications, analog control schemes are not suitable for the automotive industry, whereas digital control methods successfully meet the demands. Various types of digital control techniques for dc-dc converters are studied and classified in this paper. The drawbacks and advantages of each method are described.

Bs News

Building Services Engineering

No abstract provided.

Solving Generalized Open Constraint Optimization Problem Using Two-Level Multi-Agent Framework, Hoong Chuin Lau, Lei Zhang, Chang Liu

Research Collection School Of Computing and Information Systems

The Open Constraint Optimization Problem (OCOP) refers to the COP where constraints and variable domains can change over time and agents' opinions have to be sought over a distributed network to form a solution. The openness of the problem has caused conventional approaches to COP such as branch-and-bound to fail to find optimal solutions. OCOP is a new problem and the approach to find an optimal solution (minimum total cost) introduced in [1] is based on an unrealistic assumption that agents are willing to report their options in nondecreasing order of cost. In this paper, we study a generalized OCOP …

Stabilization And Improvement Of Organic Soils, Joonho Hwang, Aaron Humphrey, Antonio Bobet, Maria Caterina Santagata

JTRP Technical Reports

Peats and organic soils in general pose significant problems to geotechnical engineers due to their low strength, high compressibility and elevated creep. The research performed addressed one soil improving technique, deep soil mixing, that has been widely used for treating soft clays, but that especially in the US has found limited use in presence of organic soils. The work performed made use primarily of one soil sampled on Lindberg Road (LR) in West Lafayette, IN characterized by LOI= 45-52%, LL= 327%, PL= 162%, LLoven dried/LLnon-dried = 0.31, Gs = 2.05-2.12, fiber content ~2.29%, clay fraction = 40.6%. In addition, a …

Rate Dependence And Short Term Creep Behavior Of Pmr-15 Neat Resin At 23 And 288°C, Candice M. Westberry

Theses and Dissertations

This research focuses on experimental investigation of rate-dependent behavior and short-term creep of PMR-15 neat resin at 23 and 288°C. Effect of loading rate on monotonic stress-strain behavior was explored in monotonic tests at constant stress rates of 0.75, 0.075, and 0.0075 MPa/s at 23 and 288°C. In addition, effect of prior stress rate on creep behavior was explored in creep tests preceded by uninterrupted loading to a target stress. At each temperature three creep tests were conducted for a given stress level, where loading rate was changed from test to test. Creep stress levels were 30 and 25 MPa …

Investigation Of The Performance Characteristics Of Re-Entry Vehicles, Charles A. Bilbey Jr.

Theses and Dissertations

When a non-US spacecraft reenters the Earth's atmosphere, having the ability to accurately determine its performance characteristics is a primary concern. This study investigated the atmospheric re-entry profiles of a maneuverable re-entry vehicle. The re-entry vehicle was modeled as a point mass with aerodynamic properties. Equations of motion were numerically integrated, giving the time histories of position, velocity and flight path angle. The algorithm is able to generate a complete and feasible entry trajectory of a approximately 25-minute flight time in about 5 to 10 seconds on a desktop computer, given the entry conditions and values of constraint parameters. This …

Partial Adjustable Autonomy In Multi-Agent Environment And Its Application To Military Logistics, Hoong Chuin Lau, Lucas Agussurja, Ramesh Thangarajoo

Research Collection School Of Computing and Information Systems

In a rapidly changing environment, the behavior and decision-making power of agents may have to be adaptive with respect to a fluctuating autonomy. In this paper, a centralized fuzzy approach is proposed to sense changes in environmental conditions and translate them to changes in agent autonomy. A distributed coalition formation scheme is then applied to allow agents in the new autonomy to renegotiate to establish schedule consistency. The proposed framework is applied to a real-time logistics control of a military hazardous material storage facility under peace-to-war transition.

Manufacturing Companies And The Information Age In The U.S., Marcos Reynero

Graduate Research Papers

The purpose of this research paper is to analyze the relationship between the amount of indirect labor and value added in manufacturing companies. Companies are moving manufacturing sites overseas in order to reduce cost. The cost of direct labor in countries like China is relatively lower in comparison to the cost of labor in the U.S. Edward Hill, professor at Cleveland State University's College of Urban Affairs, states that an hour of a manufacturing plant in the U.S. costs $150 versus $1 in China (Scherer, 2005). Companies are making strategic decisions based on reducing cost in order to improve profits. …

Atpg For Reversible Circuits Using Technology-Related Fault Models, Jeff S. Allen, Jacob D. Biamonte, Marek Perkowski

Electrical and Computer Engineering Faculty Publications and Presentations

We address the problem of test set generation and test set reduction, to first detect, and later localize faults occurring in reversible circuits. Reversible Computation has high promise of low power consumption. Some new fault models are first presented here. An explanation of the new fault models is made based on a physical realization representing the state of the art in the reversible CMOS circuit technology. Evidence is then presented showing that the fault models presented in the current literature are not adequate for existing realizations of reversible logic such as CMOS. We designed a ATPG software package with a …

Impact Of Receive Amplifier Signal Coupling On Mimo System Performance, Michael A. Jensen, Matthew L. Morris

Faculty Publications

This paper uses a detailed model of multiple input multiple output (MIMO) systems to explore the impact of signal coupling in the receiver front end on communication capacity. The model is applied to assess the performance of a MIMO system with two transmit and receive antennas in a simulated multipath environment for different amplifier coupling levels. The results show that in practical scenarios where simple impedance matching techniques are used, the circuit coupling can reduce the signal-to-noise ratio at the receiver and therefore degrade the achievable MIMO capacity.

Static And Dynamic Obstacle Avoidance For Miniature Air Vehicles, Jeffery Brian Saunders, Brandon Call, Andrew Curtis, Randal W. Beard, Timothy W. Mclain

Faculty Publications

Small unmanned air vehicles are limited in sensor weight and power such that detection and avoidance of unknown obstacles during flight is difficult. This paper presents a low power low weight method of detection using a laser range finder. In addition, a rapidly-exploring random tree algorithm to generate waypoint paths around obstacles known a priori is presented, and a dynamic geometric algorithm to generate paths around detected obstacles is derived. The algorithms are demonstrated in simulation and in flight tests on a fixed-wing miniature air vehicle (MAV).