High-voltage (270 V) dc power-generating system for fighter aircraft

The advantages of using high voltage, direct current advanced power generating systems in fighter aircraft are discussed. Weight reduction is achieved. Efficiency is increased 85 to 90 percent by eliminating the constant speed drive. Power interruptions are eliminated. There are no speed restrictions and no powerline constraints. Personal safety is increased by eliminating the hold on frequency, present in ac systems, which causes muscle contractions

Pathway Analysis of Contaminant Fate and Transport for Generic Soil Standards and Application to Kentucky Underground Storage Tanks

A generic contaminant migration pathway was used to develop concentration adjustment factors relating soil contamination levels to concentrations in migrating media. These concentration adjustments are based on relatively simple models and parameter values from the literature. The methodology is a screening level tool and is not designed to be used in the site specific analysis where additional information on the source of contamination and the local conditions is available. The results demonstrate that contaminant concentrations can be very sensitive to the processes which occur during the migration of contaminants.Because the rates of these processes may be site specific it is difficult to assign values to many of the parameters required to describe them. The parameter estimates used at the different steps in the analysis are based on the results of a literature investigation and an understanding of the hydrogeology of Kentucky. It is apparent from this study that the multipliers are quite sensitive to parameter values selected, particularly for degradation. The sensitivity of the multipliers reinforces the need to validate these results with monitoring at existing sites. Further research on the anticipated values and conditions will be valuable in refining estimates of contaminant biodegradation for generic standards determination

Evaluation of Solids Generation in Lagoon Treatment Systems: Application to Bardstown, Kentucky

This report summarizes the results of a study which investigated the sludge accumulation in lagoon systems through both literature review and evaluation of the Bardstown wastewater treatment plant. Much of the information in this report has been presented in more detail in the Master\u27s thesis of Jon Keeling (Keeling, 1994)

Fragility of time-reversal symmetry protected topological phases

The second law of thermodynamics points to the existence of an `arrow of time', along which entropy only increases. This arises despite the time-reversal symmetry (TRS) of the microscopic laws of nature. Within quantum theory, TRS underpins many interesting phenomena, most notably topological insulators and the Haldane phase of quantum magnets. Here, we demonstrate that such TRS-protected effects are fundamentally unstable against coupling to an environment. Irrespective of the microscopic symmetries, interactions between a quantum system and its surroundings facilitate processes which would be forbidden by TRS in an isolated system. This leads not only to entanglement entropy production and the emergence of macroscopic irreversibility, but also to the demise of TRS-protected phenomena, including those associated with certain symmetry-protected topological phases. Our results highlight the enigmatic nature of TRS in quantum mechanics, and elucidate potential challenges in utilising topological systems for quantum technologies.Simons Foundatio

Kentucky Municipal Wastewater Treatment Plant Sludge Survey

A survey of solids removal from municipal wastewater treatment plants in Kentucky was conducted by the Department of Civil Engineering at the University of Kentucky. The survey was made using both a mailed form and a followed up phone communication through a period from June, 1993 to April, 1994. The results of that survey were compiled using a spreadsheet program and are available on diskette from the authors. The results of the survey are also presented in the eight Tables herein

Lumped mass modelling for the dynamic analysis of aircraft structures

Aircraft structures may be modelled by lumping the masses at particular strategic points and the flexibility or stiffness of the structure is obtained with reference to these points. Equivalent moments of inertia for the section at these positions are determined. The lumped masses are calculated based on the assumption that each point will represent the mass spread on one half of the space on each side. Then these parameters are used in the differential equation of motion and the eigen characteristics are determined. A comparison is made with results obtained by other established methods. The lumped mass approach in the dynamic analysis of complicated structures provides an easier means of predicting the dynamic characteristics of these structures. It involves less computer time and avoids computational errors that are inherent in the numerical solution of complicated systems

Kentucky Municipal wastewater Sludge: Generation, Management and Pathogen Reduction

This document was prepared as part of an investigation into sludge quantities and pathogen reduction. It has been written as an introduction and reference for operators, municipal officials, engineers and regulators as they assess their sludge management options

Municipal Wastewater Sludges: Solids Generation and Pathogen Reduction

The qualities of sludge generated and the variations in potential processing technologies for pathogen reduction pose a challenge to those evaluating sludge management. Some of the key factors that should be considered when evaluating sludge management options include: Land requirements Equipment requirements Availability of Required additives Desired product end use The extent to which these factors influence the implementation of a particular processing technology will vary, but in all cases, they will influence the cost and application of any of the technologies

Closed Universes With Black Holes But No Event Horizons As a Solution to the Black Hole Information Problem

We show it is possible for the information paradox in black hole evaporation to be resolved classically. Using standard junction conditions, we attach the general closed spherically symmetric dust metric to a spacetime satisfying all standard energy conditions but with a single point future c-boundary. The resulting Omega Point spacetime, which has NO event horizons, nevertheless has black hole type trapped surfaces and hence black holes. But since there are no event horizons, information eventually escapes from the black holes. We show that a scalar quintessence field with an appropriate exponential potential near the final singularity would give rise to an Omega Point final singularity.Comment: 27 pages in LaTex2e, no figure

Sorption of Chlorinated Organic Compounds by Sedimentary Rocks

The sorption of dichlorobenzene and trichlorobenzene on carbonate and shale rocks collected in Kentucky demonstrate that rock organic matter content is a good indicator of sorptive reactivity in rock systems. Although this is similar to soil systems, significant differences between sorption in rock and soil systems exist. Sorption isotherms on these rocks are nonlinear and sorption can be an order of magnitude higher than predicted using correlations from soils and their organic matter content. This sorption reaction could lead to significant concentration tailing during contaminant cleanup. Experimental elution of trichloroethylene from rock filled columns verified that cleanup times might be extended due to both sorption and diffusion into rock