Digital Commons Network^™

Characterization And Modeling Of Local Electromechanical Response In Stress-Biased Piezoelectric Actuators, N. Navapan-Traiphol, Robert W. Schwartz, Daniel S. Stutts, J. Wood

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Numerous investigators have explored the factors that contribute to the high electromechanical performance of stress-biased actuators with particular attention being given to the importance of the extrinsic (domain wall translation) response mechanism. Based on the variation in lateral stress through the thickness of the piezoelectric layer within these devices, it has been suggested that the piezoelectric coefficient varies as a function of position within the layer, though no direct evidence has been previously presented. In this study, the results of Moire interferometry investigations of local strains within these devices are reviewed. The technique permits effective depth-profiling of local deformations at …

Design And Technologies For A Smart Composite Bridge, K. Chandrashekhara, Prakash Kumar, Steve Eugene Watkins, Antonio Nanni

Mechanical and Aerospace Engineering Faculty Research & Creative Works

An all-composite, smart bridge design for shortspan applications is described. The bridge dimensions are 9.14-m (30-ft.) long and 2.74-m (9-ft.) wide. A modular construction based on assemblies of pultruded fiber-reinforced-polymer (FRP) composite tubes is used to meet American Association of State Highway and Transportation Officials (AASHTO) H20 highway load ratings. The hollow tubes are 76 mm (3 in.) square and are made of carbon/vinyl-ester and glass/vinyl-ester. An extensive experimental study was carried out to obtain and compare properties (stiffness, strength, and failure modes) for a quarter portion of the full-sized bridge. The bridge response was measured for design loading, two-million-cycle …

Development And Analysis Of A Feedback Treatment Strategy For Parturient Paresis Of Cows, Radhakant Padhi, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

An intelligent on-line feedback treatment strategy based on nonlinear optimal control theory is presented for the parturient paresis of cows. A limitation in the development of an existing nonlinear mathematical model for the homogeneous system is addressed and further modified to incorporate a control input. A neural network based optimal feedback controller is synthesized for the treatment of the disease. Detailed studies are used to analyze the effectiveness of a feedback medication strategy and it is compared with the current "impulse" strategy. The results show that while the current practice may fail in some cases, especially if it is carried …

Development And Implementation Of New Nonlinear Control Concepts For A Ua, Vijayakumar Janardhan, Derek Schmitz, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A reconfigurable flight control method is developed to be implemented on an Unmanned Aircraft (UA), a thirty percent scale model of the Cessna 150. This paper presents the details of the UAV platform, system identification, reconfigurable controller design, development, and implementation on the UA to analyze the performance metrics. A Crossbow Inertial Measurement Unit provides the roll, pitch and yaw accelerations and rates along with the roll and pitch. The 100400 mini-air data boom from spaceage control provides the airspeed, altitude, angle of attack and the side slip angles. System identification is accomplished by commanding preprogrammed inputs to the control …

Optimal Beaver Population Management Using Reduced Order Distributed Parameter Model And Single Network Adaptive Critics, Radhakant Padhi, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Using a distributed parameter model for beaver population that accounts for their spatial and temporal behavior, an optimal control for a desired distribution of the animals is presented. Optimal solutions are obtained through a "single network adaptive critic" (SNAC) neural network architecture. The objective of this research is to design an "optimal" beaver harvesting scheme for a region of interest.

Optimal Control Synthesis Of A Class Of Nonlinear Systems Using Single Network Adaptive Critics, Radhakant Padhi, Nishant Unnikrishnan, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Adaptive critic (AC) neural network solutions to optimal control designs using dynamic programming has reduced the need of complex computations and storage requirements that typical dynamic programming requires. In this paper, a "single network adaptive critic" (SNAC) is presented. This approach is applicable to a class of nonlinear systems where the optimal control (stationary) equation is explicitly solvable for control in terms of state and costate variables. The SNAC architecture offers three potential advantages; a simpler architecture, significant savings of computational load and reduction in approximation errors. In order to demonstrate these benefits, a real-life micro-electro-mechanical-system (MEMS) problem has been …

Solid State Aircraft Concept Overview, M. Shahinpoor, P. Jenkins, C. Smith, Kakkattukuzhy M. Isaac, T. Dalbello, Anthony Colozza

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Due to recent advances in polymers, photovoltaics, and batteries a unique type of aircraft may be feasible. This is a "solid-state" aircraft, with no conventional mechanical moving parts. Airfoil, propulsion, energy production, energy storage and control are combined in an integrated structure. The key material of this concept is an ionic polymeric-metal composite (IPMC) that provides source of control and propulsion. This material has the unique capability of deforming in an electric field and returning to its original shape when the field is removed. Combining the IPMC with thin-film batteries and thin-film photovoltaics provides both energy source and storage in …

Stationkeeping Of An L₂ Libration Point Satellite With Θ-D Technique, Ming Xin, S. N. Balakrishnan, Henry J. Pernicka, Michael W. Dancer

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A new method for L₂ libration-point orbit stationkeeping is proposed in this paper using continuous thrust. The circular restricted three-body problem with Sun and Earth as the two primaries is considered. The unstable orbit about the L₂ libration-point requires stationkeeping maneuvers to maintain the nominal path. In this study, an approach, called the "θ-D technique," based on optimal control theory gives a closed-form suboptimal feedback solution to solve this nonlinear control problem. In this approach the Hamiltonian-Jacobi-Bellman (HJB) equation is solved approximately by adding some perturbations to the cost function. The controller is designed such that the actual …

Government Policy Towards Innovation In The United States, Canada, And The European Union As Manifested In Patent, Copyright, And Competition Laws, Daniel J. Gifford

Articles

THE United States, Canada, the European Union, Japan and most industrialized nations have adopted patent, copyright and other intellectual property laws. A major or primary purpose of those laws is to foster innovation, including technological innovation. Industrial and technological innovation is generally perceived as a good because technological advances increase a society's productivity, 1 thus increasing its wealth and raising living standards. The major industrialized nations also possess competition laws, one of whose purposes is to preserve, foster and support competitive markets. These nations want to preserve competitive markets because competitive markets help to allocate available resources to their highest …

Turbine Blade Tip Cooling And Heat Transfer, Hasan Nasir

LSU Doctoral Dissertations

Turbine blade tip leakage flow from blade pressure side to suction side over the tip surface increases the thermal loading to the blade tip, leading to a high local temperature and thus, is considered one of the primary sources of blade failure. Leakage flow can be reduced by using a recessed or squealer tip blade or by cooling the blade tip to incorporate film cooling. The performance of different recessed tip geometries were investigated and compared with plane tip performance. A transient liquid crystal technique was employed to measure detailed heat transfer coefficient distributions. Coolant injection from holes located on …

Construct Validation Of An Arabic Version Of The Learning Transfer System Inventory For Use In Jordan, Samer Abdelkarim Khasawneh

LSU Doctoral Dissertations

Organizations in Jordan have invested heavily in employee training. However, these training efforts may not be as effective. One area of particular interest is learning transfer, or the extent to which learning from training is applied on the job. Recent research efforts have led to the development of the Learning Transfer System Inventory (LTSI), the only valid and reliable measure of key transfer system factors. This study validated the constructs of the LTSI for use in Jordan. By doing so, HRD practitioners in Jordan can use such instrument to diagnose early problems with learning transfer, the key to training effectiveness …

Constructive Habituation As An Educational Approach To Process-Object Reification In Mathematics, Alonzo F. Peterson

LSU Doctoral Dissertations

Sfard and Thompson (1994) state that what matters most is that educators develop ways of thinking, teaching, and learning mathematics. This study introduced constructive habituation, a new strategy developed to aid both students and teachers in the thinking, teaching, and learning of mathematics. Constructive habituation attempts to unite constructivist teaching methods aimed at supporting students’ conceptual understanding of content and habituationist teaching method aimed at establishing routine responses to routine tasks. This study is exploratory in nature, designed to investigate if constructive habituation is a more effective means than a traditional teaching method in helping students reach process-object reification as …

Quantification Of Marine Sediment Properties From Planar And Volumetric Pore Geometries, Allen Hagerman Reed

LSU Doctoral Dissertations

Pore geometry and topology are important determinants of sediment physical properties, such as porosity and permeability. They also influence processes that occur in the sediment, such as acoustic propagation, attenuation, and dispersion, single- and multi-phase fluid flow, and hydrodynamic dispersion. This study uses images to evaluate pore geometry and topology of ooid (subspherical particles) and siliclastic (angular quartz) sand that was collected from the marine environment south of Bimni Bahamas and Ft. Walton Beach, FL, respectively. Image analysis techniques and predictive tools enable insight into the relationships among sediment pore geometry, topology, and physical properties for these differently shaped sands. …

Recent Trends In Software Engineering Research As Seen Through Its Publications, Terry L. Smith

UNF Graduate Theses and Dissertations

This study provides some insight into the field of software engineering through analysis of its recent research publications. Data for this study are taken from the ACM's Guide to Computing Literature (GUIDE) They include both the professionally assigned Computing Classification System (CCS) descriptors and the title text of each software engineering publication reviewed by the GUIDE from 1998 through 2001.

The first part of this study provides a snapshot of software engineering by applying co-word analysis techniques to the data. This snapshot indicates recent themes or areas of interest, which, when compared with the results from earlier studies, reveal current …

A Test Suite Generator For Struts Based Applications, Gregory M. Jackson

UNF Graduate Theses and Dissertations

Testing web-based enterprise applications requires the use of automated testing frameworks. The testing framework's ability to run suites of test cases through development ensures enhancements work as required and have not caused defects in previously developed sub systems. Open source testing frameworks like JUnit and Cactus have addressed the requirements to test web-based enterprise applications, however they do not address the generation of test cases based on direct analysis of the code under test.

This paper presents a tool to generate test cases for web-based enterprise applications. The generator focuses on creating test cases used to test applications built on …

Bob Hudec: Our Days At The Court, Thomas E. Kauper

Minnesota Journal of International Law, Vols 1-28:1 (1992-2019)

No abstract provided.

Compact High-Voltage Generator Of Primary Power Based On Shock Wave Depolarization Of Lead Zirconate Titanate Piezoelectric Ceramics, Sergey I. Shkuratov, Evgueni F. Talantsev, Latika Menon, Henryk Temkin, Jason Baird, Larry L. Altgilbers

Mining Engineering Faculty Research & Creative Works

The design and performance of a compact explosive-driven high-voltage primary power generator is presented. The generator utilizes a fundamental physical effect—depolarization of ferroelectric materials under longitudinal shock wave impact, when the shock wave is initiated along the polarization vector P. These primary power sources, containing energy-carrying elements made of lead zirconate titanate poled piezoelectric ceramics, with the volume from 0.35 to 3.3 cm3, are capable of producing pulses of high voltage with amplitudes up to 21.4 kV. The amplitude and full width at half-maximum of the high-voltage pulses are directly proportional to the thickness of the energy-carrying element, with coefficients …

Adjusting The Low Energy Threshold For Large Bodies In Pet, John W. Wilson, Timothy G. Turkington, James G. Colsher

Mining Engineering Faculty Research & Creative Works

The performance of a PET scanner on three different phantom sizes was studied as a function of low energy threshold (LET). Phantom cross sections ranged from 20 cm diameter circular to 28 cm x 43 cm oval and LET''s ranged from 350 keV to 475 keV, in 25 keV increments. System sensitivity, scatter fraction, and NEC were measured over a wide range of radioactivity levels. Increasing the low energy threshold lowered both sensitivity and scatter fraction. The statistical quality of the raw data was maximized for the 425 keV setting for all three phantoms. System stability and uniformity of response …

Optimizing Sequential Dual Tracer P.E.T. Studies Using A Combined 2d/3d Imaging Protocol, John W. Wilson, S. Borges-Neto, Timothy G. Turkington, James G. Colsher, R. E. Reiman, R. E. Coleman

Mining Engineering Faculty Research & Creative Works

We have investigated a combined 2D/3D protocol for minimizing contamination in dual tracer P.E.T. studies in which the tracers are administered on a timescale that is short compared to the half-lives. We have performed a series of phantom studies on an Advance and a Discovery ST (GE Healthcare Technologies), using a torso phantom with cardiac insert (Data Spectrum Corporation) to simulate a combined FDG and NH3 scan protocol for a patient with ischemia. The phantom was imaged in a series of alternating 2D/3D acquisitions as it decayed over 6 half-lives. By comparing 2D and 3D images, we have verified that …

The Rollamo 2004, University Of Missouri - Rolla

Yearbooks

No abstract provided.

Thermal Efficiency Of Steel Melting, Kent D. Peaslee, Semen Naumovich Lekakh, Bradley Randall

Materials Science and Engineering Faculty Research & Creative Works

This paper presents the results of energy consumption measurements at steel foundries using induction and/or electric arc furnace melting. Statistical methods, infrared thermography, and numerical investigations were used for analysis of heat losses. The influence of different melting practices on energy losses was examined. Industrial experiments in isothermal holding of liquid steel in induction furnaces under different power inputs were used for evaluation of the real values of heat losses by radiation from liquid steel and conductivity through lining. Average values and statistical distributions of energy consumptions for melting steel are presented in this article.

Evaluation Of Microstructure And Superplasticity In Friction Stir Processed 5083 Al Alloy, Indrajit Charit, Rajiv S. Mishra

Materials Science and Engineering Faculty Research & Creative Works

Friction stir processing (FSP) has been developed as a potential grain refinement technique. In the current study, a commercial 5083 Al alloy was friction stir processed with three combinations of FSP parameters. Fine-grained microstructures with average grain sizes of 3.5-8.5 µm were obtained. Tensile tests revealed that the maximum ductility of 590 was achieved at a strain rate of 3 x 10^-3 s^-1 and 530 °C in the 6.5-µm grain size FSP material, whereas for the material with 8.5-µm grain size, maximum ductility of 575 was achieved at a strain rate of 3 x 10^-4 s^{-1 …}

High Gradient Multilayer Insulator Technology, Harlan U. Anderson, Stephen E. Sampayan, G. J. Caporaso, W. C. Nunnally, D. M. Sanders, J. A. Watson, Mike L. Krogh

Materials Science and Engineering Faculty Research & Creative Works

We are investigating a novel insulator concept that involves the use of alternating layers of conductors and insulators with periods less than 1 mm. These structures perform 1.5 to 4 times better than conventional insulators in long pulse, short pulse, and alternating polarity applications. We have surveyed our ongoing studies by investigating the performance under long pulse electron beam, short pulse, and full reversing conditions.

Kinetics Of Binary Nucleation Of Vapors In Size And Composition Space, Sergey P. Fisenko, Gerald Wilemski

Physics Faculty Research & Creative Works

We reformulate the kinetic description of binary nucleation in the gas phase using two natural independent variables: the total number of molecules g and the molar composition x of the cluster. The resulting kinetic equation can be viewed as a two-dimensional Fokker-Planck equation describing the simultaneous Brownian motion of the clusters in size and composition space. Explicit expressions for the Brownian diffusion coefficients in cluster size and composition space are obtained. For characterization of binary nucleation in gases three criteria are established. These criteria establish the relative importance of the rate processes in cluster size and composition space for different …

Study Of Structural And Magnetic Properties Of Iron-Rich Mixed Rare-Earth Nddyfe (17-Y-X)Coxsiy Compounds, Kishore Kamaraju, Jinbo Yang, William B. Yelon, Oran Allan Pringle, M. S. Kim, Qingsheng Cai, William Joseph James

Physics Faculty Research & Creative Works

A series of NdDyFe(17-y-x)CoxSiy solid solutions with = 2 and 3 and = 0.5 1.0 and 1.5 were prepared by induction melting stoichiometric amounts of high-purity elements. The postannealed samples consist of two phases belonging to the space groups R3 m and P63 mmc . The lattice parameters and the unit cell volumes were calculated from the refinements of the magnetic and structural unit cells using the FULLPROF version of the Rietveld program. For a fixed content of Co, the maximum Curie temperatures (305 C to 405 C) were observed in samples with = 1 and having two phases, a …

An Integral Form Of The Variational Nodal Method, M. A. Smith, G. Palmiotti, E. E. Lewis, Nicholas Tsoulfanidis

Nuclear Engineering and Radiation Science Faculty Research & Creative Works

An integral form of the variational nodal method is formulated, implemented, and tested. the method combines an integral transport treatment of the even-parity flux within the spatial node with an odd-parity spherical harmonics expansion of the Lagrange multipliers at the node interfaces. the response matrices that result from this formulation are compatible with those in the VARIANT code at Argonne National Laboratory. Spatial discretization within each node allows for accurate treatment of homogeneous or heterogeneous node geometries. the integral method is implemented in Cartesian x-y geometry and applied to three benchmark problems. the method's accuracy is compared to that of …

Biomarkers Of Chemical Impacts In The Freshwater Invertebrates Asellusaquaticus And Pacifastacus Leniusculus, Anne Jennie O'Neill

School of Biological and Marine Sciences Theses

The international scientific community has grown increasingly concerned that exposure to low levels of anthropogenic chemicals may disturb hormone function and/or sub lethal toxicity to other cells or organ systems in vertebrate and invertebrate species. This research programme was designed to develop, evaluate, and apply a range of biological and chemical indicators in the laboratory and/or field to assess the impact of sublethal toxicants including potential endocrine disaipting chemicals in the aquatic invertebrates, Asellus aquaticus (isopod) and Pacifasiacus leniiisciiius (decapod). Laboratory exposures of A. aquaticiis to environmentally realistic concentrations of known contaminants present within the river systems have demonstrated a …

Tool Management In Flexible Manufacturing Systems, Ahmet Soylemezoglu

Masters Theses

"In this study, impact of cutting tool life and tool slot size on tool management in Flexible Manufacturing Systems (FMS) is investigated. A conceptual tool management framework, which has been proposed by Buyurgan, Saygin, and Kilic (2003), is modified and implemented in a simulation environment in order to assess its performance. This model, namely LS Model (LS stands for Life and Size), makes decisions by considering both tool life and tool slot size. An alternative tool management model that makes decisions based only on tool life, namely LO Model (LO stands for Life Only), is developed in order to make …

Deceived By Disparity Studies: Why The Tenth Circuit Failed To Apply Croson's Strict Scrutiny Standard In Concrete Works Of Colorado, Teresa Lee Brown

Denver Law Review

No abstract provided.

Vol. 81, No. 3: Full Issue, Denver University Law Review

Denver Law Review

No abstract provided.