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Bulletin - Fall, 1992, Civil Aviation Medical Association

Browse all Civil Aviation Medical Association Newsletters

A sixteen page newsletter of the Civil Aviation Medical Association. The newsletter provided news about civil aviation medicine and information related to the organization.

Object-Oriented Modeling Of Communication Systems, Kurt Louis Kosbar, Kevin W. Schneider

Electrical and Computer Engineering Faculty Research & Creative Works

Conventional communication system simulation programs and packages are written using procedural programming languages. Newly developed, object-oriented languages offer the simulation designer significantly different options and structures. By exploiting these new techniques it is possible to significantly increase the flexibility and extensibility of the simulation package. This allows the system analyst to efficiently re-use complex simulation code and quickly and reliably reconfigure the simulation. In addition, a single object-oriented simulation can be used in all stages of the design process, from conceptual design through fabrication and testing. A final benefit of the object-oriented techniques is that the simulation code closely matches …

Conservative Confidence Intervals Of Importance Sampling Estimates, Kurt Louis Kosbar, T. F. Chang

Electrical and Computer Engineering Faculty Research & Creative Works

Confidence intervals (CI) are used to gauge the accuracy of bit error rate (BER) estimates produced by Monte Carlo (MC) simulations. This work attempts to objectively evaluate the performance of Important Sampling (IS) simulations by applying the same statistical analysis tool. While it is not possible to evaluate the minimum size CI for arbitrary IS estimates, it is possible to over-bound the interval using a technique called conservative confidence interval (CCI) estimation. This bounding procedure is applied to a simple IS biasing technique. While the IS estimate may be superior to the MC estimate, the CCI fails to support this …

Analysis Of Heat Pump Cycles Using Thermodynamic Equations Of State, Stephen C. Ericson

Mechanical & Aerospace Engineering Theses & Dissertations

In this study, thermal performance of heat pump cycles is analyzed by employing several equations of state. The analysis presented here is particularly useful for applications where refrigerant properties need to be calculated from a thermodynamic equation of state. Such a situation, for example, would arise during a long-term numerical simulation of a solar-assisted heat pump system. In these cases, the direct use of thermodynamic property tables of refrigerants would not be possible in a computational procedure. The approach of using equations of state to predict thermodynamic properties is also useful for applications where new refrigerants or blends of refrigerants …

Interaction Of Profiled Light With Contrapropagating Acoustic Waves: Fourier Transform Approach, Partha P. Banerjee, Chen-Wen Tarn, Jaw-Jueh Liu

Electrical and Computer Engineering Faculty Publications

A straightforward Fourier-transform approach is employed to investigate acousto-optic interaction between an input optical beam with arbitrary profile and contrapropagating cw sound in the Bragg regime. The process can be analyzed in terms of the simultaneous scattering of light by the two sound waves in the interaction region. Analytic expressions for the equivalent transfer functions are obtained and the scattered light profiles are plotted.

Structural Characterization Of Fucoidan And Its Role In The Hemizona Assay, Manish S. Patankar

Chemistry & Biochemistry Theses & Dissertations

Fucoidan is a polysaccharide commonly found in brown algae. It is a sulfated polymer of the monosaccharide L-fucose. Fucoidan is thought to function in water retention by algae. Commercially available fucoidan is extracted from a brown algae called Eurus vesiculosus.

This polysaccharide has immense potential as a biologically active agent: (i) it exhibits anticoagulant action, (ii) it has also been reported to block retroviral replication and (iii) it is capable of blocking sperm-egg binding in sea urchin, mouse and rabbit. Recently, fucoidan has also been shown to block the interaction of human sperm and egg in the hemizona assay …

Elastic Buckling Of Stiffened Composite Curved Panels, Navin R. R. Jaunky

Mechanical & Aerospace Engineering Theses & Dissertations

Continuous filament grid-stiffened structure is a stiffening concept that combines structural efficiency and damage tolerance. However, buckle resistant design of such structures using finite elements methods is expensive and time consuming. An analytical model of a general grid stiffened structure is developed using a smeared theory with a first order shear deformation theory to account for transverse shear flexibilities. The solution for buckling of a simply supported panel subjected to combined loading is developed using energy method and a Rayleigh-Ritz technique. The smeared theory results are compared with finite element results. The results smeared theory compare well with the finite …

Axial Load Capacity Of Sheeted Cold-Formed C And Z Members, Neil J. Glaser, Richard C. Kaehler, James M. Fisher

American Iron and Steel Institute (AISI) Specifications, Standards, Manuals and Research Reports (1946 - present)

No abstract provided.

The Effect Of Additives On The Nucleation And Growth Of Copper Onto Stainless Steel Cathodes, M. Sun, Thomas J. O'Keefe

Materials Science and Engineering Faculty Research & Creative Works

A potentiostatic technique has been used to study the effects of chloride ion, glue, and thiourea on the initial electrodeposition of copper. A stainless steel (AISI 304) rotating disc electrode (RDE) with an electrolyte containing 40 g/1 Cu²⁺ and 180 g/1 H₂SO₄ at 40 °C was employed. The current transients from the potential step measurements for the additive-free electrolyte could be fitted to a model that assumed progressive nucleation followed by growth of three-dimensional (3-D) centers under diffusion control. The growth mechanism and the type of nuclei were also confirmed by scanning electron microscopy (SEM) of …

A Fracture Mechanics Analysis Of A 38 Inch Diameter Hot Pressed Beryllium Telescope Mirror, Phillip L. Brown

Mechanical & Aerospace Engineering Theses & Dissertations

A 38 inch diameter hot pressed beryllium telescope mirror was analyzed for structural integrity using finite-element modeling and a fracture mechanics analysis program, ZIP3D, developed for three-dimensional (3-0) solid and cracked bodies. The calculation of stress and mixed-mode fracture mechanics parameters for the mirror critical stress area was the objective of the mirror analysis.

Finite-element modeling for ZIP3D solution was performed in two stages. The first stage modeling modeled the mirror configuration on a global basis for calculation of accurate nodal displacements. The second stage modeling reduced the modeled mirror configuration to a set of localized models for calculation of …

Interval Estimation And Monte Carlo Simulation Of Digital Communication Systems, Kurt Louis Kosbar, T. F. Chang

Electrical and Computer Engineering Faculty Research & Creative Works

This work quantifies the accuracy of bit error rate (BER) estimates produced by Monte Carlo simulations by carefully applying confidence interval estimation techniques. Due to numerical difficulties, some previous work in this area has assumed that the BER statistic possessed a Gaussian distribution. This work demonstrates that in some important regions the estimate is decidedly non-Gaussian, and application of central limit theorem arguments can result in errors in excess of an order of magnitude. This work investigates the accuracy of common approximations and the feasibility of exact calculation of confidence intervals, and presents a novel polynomial class approximation. By combining …

Construction Of Highway Base And Subbase Layers Containing Residue From An Atmospheric Fluidized Bed Combustion Process, David Q. Hunsucker, R. Clark Graves

Kentucky Transportation Center Research Report

This report summarizes findings of laboratory and construction evaluations of using residue from an atmospheric fluidized bed combustion (AFBC) process as a component in an experimental road base and subbase application. The base mixture contains pulverized fuel ash, AFBC residue, and limestone aggregates used as bulk filler. The subbase mixture contains AFBC residue and pond ash (ponded fly ash and bottom ash). Mixtures containing various proportions of each component were evaluated in the laboratory relative to maximum dry density, optimum moisture content, and compressive strength development.

Two 750-foot test sections of a 22-foot wide roadway, containing the experimental mixtures, were …

Cost Effective Maintenance Contracting, Bobby W. Meade, David Q. Hunsucker

Kentucky Transportation Center Research Report

Increased emphasis on highway maintenance and the need to accomplish the maintenance programs as efficiently as possible, prompted this study. The objectives of the study addressed herein are the identification of maintenance activities performed by contract, determination of equivalent levels of service between contract performed and in-house performed activities, cost comparison of those activities, and recommendations to implement the findings.

Findings are that activities routinely performed by contract are cost efficient. A formal make-versus-buy decision making process should be developed. The process should be made available to District personnel and the make-versus-buy decision made at that level. Decision making processes …

Transient Simulation Of A Trombe Wall Passive Heating System Coupled To A Thermally Stratified Room, Ali Saleh Kheireddine

Mechanical & Aerospace Engineering Theses & Dissertations

Thermal performance of a Trombe-wall space heating system has been studied numerically for one-day and multiple-day periods. This study analyzes the system performance by simultaneously considering the coupled nature of the channel convection, wall heat conduction and transient room energy balance. A computer program has been written and implemented to assess the effects of system parameters, weather conditions and peak temperature control strategies on the system performance.

The system performance is influenced by such system parameters as the storage wall thickness, channel width and the temperature stratification in the room. Increasing the wall thickness decreases the temperature swings considerably, but …

Retention Of Cellular Viability And Growth Potential In Cryopreserved Bovine Arterial Tissue: Implications For Clinical Use Of Cryopreserved Vascular Allografts, Kip G. Gardner

Biological Sciences Theses & Dissertations

Segments of bovine calf aortas and pulmonary arteries were cryopreserved at -196° C for two weeks to 18 months and subsequently thawed. Cellular morphology, viability, and growth potential in these segments were then compared with the same attributes in segments from fresh (control) arteries. Scanning electron microscopy revealed no disruption of intimal surfaces attributable to cryopreservation. Endothelial cells were successfully cultured from all cryopreserved arterial segments. Endothelial monolayers grown from cryopreserved arteries had a cobblestone appearance and expressed Factor VIII antigen but not smooth muscle alpha-actin. Plating efficiency in primary cultures of endothelial cells was lower for cryopreserved arteries than …

An Experimental Study For The Effect Of Specimen Size On Shear Behavior Of Granular Materials, Clifton Linwood Parker Iv

Civil & Environmental Engineering Theses & Dissertations

An experimental study was undertaken to look into the effect of specimen size on the volumetric behavior of granular triaxial specimens. It was hypothesized that the specimen preparation mold creates a unique particle arrangement near the perimeter of the specimen and thus, for smaller specimen diameter relative to the particle size, it will exhibit a greater effect of the unique particle arrangement on the volumetric behavior. particles was used A single distribution of spherical glass throughout the testing. The tested specimens were 3.6, 2.8, 2.0, 1.4, 1.0, and 0.6 inches in diameter with a fixed two to one specimen height …

Design And Implementation Of Fuzzy Logic Controllers, Osama A. Abihana

Electrical & Computer Engineering Theses & Dissertations

The main objectives of our research are to present a self-contained overview of fuzzy sets and fuzzy logic, develop a methodology for control system design using fuzzy logic controllers, and to design and implement a fuzzy logic controller for a real system. In this thesis we first present the fundamental concepts of fuzzy sets and fuzzy logic. Fuzzy sets and basic fuzzy operations are defined. In addition, for control systems, it is important to understand the concepts of linguistic variables, linguistic values, term sets, fuzzy rule base, inference methods, and defuzzification methods. Second, we introduce a four-step fuzzy logic control …

The Effect Of Contacts On The Performance Of Electron-Beam Controlled Gaas And Diamond Switches, Michael Kevin Kennedy

Electrical & Computer Engineering Theses & Dissertations

The performance of GaAs and diamond as electron-beam controlled closing and opening switches has been studied. An emphasis has been placed on the effect of contacts on the current-voltage characteristics. The two materials studied were GaAs and diamond. Using the same semi-insulating GaAs wafer as a source of material, a bulk device and a p-i-n device have been fabricated and compared. The asymmetry of the pin diode allows operation at higher voltage because of the ability to suppress the lock-on effect. Whereas GaAs was ionized through cathodoluminescence; diamond, in the form of thin films, has been directly ionized by the …

Packet Routing In Networks With Long Wires, Ronald I. Greenberg, H.-C. Oh

Computer Science: Faculty Publications and Other Works

In this paper, we examine the packet routing problem for networks with wires of differing length. We consider this problem in a network independent context, in which routing time is expressed in terms of “congestion” and “dilation” measures for a set of packet paths. We give, for any constant ε > 0, a randomized on-line algorithm for routing any set of N packets in O((Clg^ε(Nd)+Dlg(Nd))/lglg(Nd)) time, where C is the maximum congestion and D is the length of the longest path, both taking wire delays into account, and d is the longest path in terms of number of wires. We also …

Appendix: List Of Participants [1992], Kentucky Transportation Center

Kentucky's Annual Forum on Transportation

No abstract provided.

Transportation Of The Future And The Future Of Transportation, Lee T. Todd Jr.

Kentucky's Annual Forum on Transportation

No abstract provided.

Transportation Of The Future And The Future Of Transportation, John A. Deacon

Kentucky's Annual Forum on Transportation

No abstract provided.

Intermodalism: What It Is And How It Works. Transamerica Transportation Corridor Transportation Options For The Twenty-First Century, James L. Covil

Kentucky's Annual Forum on Transportation

No abstract provided.

Intermodalism: What It Is And How It Works. Intermodal Transportation: Past, Present, And Future, Benjamin J. Allen

Kentucky's Annual Forum on Transportation

No abstract provided.

Transportation: We Shape It And It Shapes Us, J. M. Yowell

Kentucky's Annual Forum on Transportation

No abstract provided.

Intermodal Surface Transportation Efficiency Act (Istea): A New Way Of Doing Business, James Q. Duane

Kentucky's Annual Forum on Transportation

No abstract provided.

Intermodal Surface Transportation Efficiency Act (Istea): A New Way Of Doing Business, Roland J. Mross

Kentucky's Annual Forum on Transportation

No abstract provided.

Intermodal Surface Transportation Efficiency Act (Istea): A New Way Of Doing Business, Douglas B. Ham

Kentucky's Annual Forum on Transportation

No abstract provided.

Intermodal Surface Transportation Efficiency Act (Istea): A New Way Of Doing Business, Eugene R. Mccormick

Kentucky's Annual Forum on Transportation

No abstract provided.

Understanding Transportation In The Commonwealth: How Decisions Of The Past Affect Us Today: Kentucky Overview, Calvin G. Grayson

Kentucky's Annual Forum on Transportation

No abstract provided.