4,668 research outputs found

    Speech therapy and voice recognition instrument

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    Characteristics of electronic circuit for examining variations in vocal excitation for diagnostic purposes and in speech recognition for determiniog voice patterns and pitch changes are described. Operation of the circuit is discussed and circuit diagram is provided

    Heat and Moisture Conduction in Unsaturated Soils

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    Mathematical models are developed for the prediction of heat transfer from hot water pipes buried in the soil. Heat transfer in the absence of moisture transfer is described as a function of the difference between the temperature of the pipe and the temperature of the soil surface. The energy balance is used to determine the longitudinal temperature distribution of the water. The method is extended to describe a system of equally spaced, parallel buried pipes. Soil temperature profiles around the pipes are presented. The model is used to calculate the land area that can be heated by an underground piping system carrying cooling water from the condensers of a 1000 MW nuclear-electric plant. A new development of the phenomenological equations for coupled heat and moisture flow, based on the theory of Irreversible Thermodynamics, is presented. Solutions of the equations for boundary conditions representative of buried piping systems designed for simultaneous soil heating and irrigation are presented

    Experimental investigation of the effect of general imperfections on the buckling of cylindrical shells

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    Imperfection survey data on cylindrical shells before and during axial compression loading up to buckling loa

    Micromation and Micrographics

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    Commercial data processing systems of all generations, first, second and third, have been plagued by a serious imbalance of speeds. While all functions of information systems input, processing, and output are interrelated they have been sadly out of balance in speed relationships one to the other. A major objective of the Non-Impact Printing Project (NIPP) (now titled Micremation) was to devise a solution to the crucial imbalance on the output side of the computer. Providing adequate on-time information to operational levels is solving only part of the output problem. Management, while leaning heavily on computers to answer their day to day operational needs with thousands of lines of data, is still looking for a system which will reduce this data to a format which facilitates a review and analysis of current status and trends. Concepts now under development during Phase III of NIPP will approach this problem toward a solution. Frequently referenced in this document will be the term Micromation System. It can be considered as a system which combines the technology of computers and high speed microfilm recorders to solve major problems in information management. Discussions further in the text will indicate how Micromation has afforded a practical solution to fill the speed gap between fast automatic data processors and slow output printing systems, much to the satisfaction of both the data processing manager and his customer. To eliminate confusion on the part of the reader, it should be understood that unless otherwise qualified, the media of microfilm which will be under discussion throughout this document will be l6mm roll film, in cartridges. The advantages of compactness, low cost, and ease of use make this media particularly suitable to business information systems. The term business is used here to indicate information systems designed to support the management and operational aspects of logistics, finance, personnel, and other similar areas which are computerized and non-scientific

    Virtual Substrate Synthesis for Low-Cost High Efficiency III-V

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    The use of the low-cost thin-film vapor-liquid-solid (TF-VLS) method in the manufacturing of III-V solar cell substrates has the potential to provide a lightweight, flexible, and cheaper alternative to traditional III-V substrates typical of state-of-the- art power generation technology. The TF-VLS process has been shown to produce high optoelectronic quality polycrystalline InP on lightweight flexible metal foils. In this work, this novel method is applied to the growth of binary and ternary III-V materials which include: InP, InAs, and InGaP on Mo foils and/or sputtered Mo on Si wafers. As a result of InP trials, powder XRD measurements have identified the presence of polycrystalline InP peaks and the absence of pure unbound In peaks, signifying full consumption of In by InP formation. Photoluminescence measurements show InP samples emit in close agreement to the InP bandgap of 1.34 eV and share similar FWHM values with single crystal InP, indicating the optical properties of the TF-VLS grown material is similar to that of single crystal InP. Cross-section SEM of InP grown on Mo/Si demonstrate crystal growth in a planar format without defects such as pinholes or voids throughout the InP layer. A series of studies were performed to investigate the effects of varying phosphorization parameters such as temperature and partial pressure of phosphorous gas. Temperature studies show that varying phosphorization temperatures do not seem to have a pronounced effect on crystallinity but they do have an effect on the optical quality of the material. For both studies, at two different partial pressures, the PL intensity for the InP grown at higher temperatures is greater than InP grown at lower temperatures, thereby indicating a temperature dependence on the optical quality of the material. Partial pressure studies revealed that samples phosphorized at lower pressures demonstrate greater PL intensities indicating higher radiative recombination efficiency and partial pressure dependence on the optical quality of the material. The TF-VLS method was expanded to polycrystalline InAs growth with trials indicating multiple InAs XRD peaks but with a number of unidentified peaks. Photoluminesce of TF-VLS grown InGaP show five distinguishable peaks corresponding to bandgaps ranging from 1.28-1.65 eV, possibly indicating different phases of InGaP or materials other than the intended InGaP. Initial In layer optimization efforts conclude that In sputtered at a low pressure (1 mTorr) show more surface coverage than at higher pressures. Electron beam studies show that surface morphology of the In layer becomes more planar and continuous with simultaneously increased deposition rate and layer thickness. Electron beam vs. RF sputtering comparison prove the former method to be vastly superior to the latter, validating electron beam deposition as the preferred In deposition method for the growth of high quality polycrystalline III-V materials. Collectively, these efforts aim to improve the novel TF-VLS growth process to provide low-cost substrates for next-generation III-V photovoltaic technology

    Investigation of Endwall Vortex Manipulation in High Lift Turbines Caused By Active Endwall Forcing

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    With the increased demand for lighter, more fuel efficient and smaller gas turbine engines, the impetus to reduce the weight and size of the turbine has become apparent. One approach to reduce this weight is to reduce the number of blades in the turbine. However, to maintain power output, each blade must be capable of supporting a greater amount of lift. While several high-lift turbine profiles have been detailed in literature, most of these profiles have increased endwall losses, despite their desirable mid-span characteristics. To mitigate this endwall loss, a number of active and passive flow approaches have been studied and reported. The current effort documents significant manipulation and reduction in strength of endwall flow features via active control in the AFRL Low Speed Wind Tunnel Test Facility. The manipulation of the pressure side leg of the horseshoe vortex, formed at the leading edge of the turbine profile, has been shown to reduce overall pressure loss near the endwall in certain active flow control conditions. The active flow took the form of a localized low-momentum pulsed jet directly under the pressure side leg of the horseshoe vortex. Total pressure loss measurements have been collected and mapped at six planes within and beyond the passage. To supplement the total pressure loss measurements, high speed stereographic particle image velocimetry data were collected to study the effects of localized forcing of the endwall flow structure. The combination of the velocity measurements at several planes throughout the passage and the total pressure loss measurements led to a deeper understanding of the fluid dynamic mechanisms responsible for the reduction in endwall losses

    Using the Rietveld Method for the Estimation and Characterization of Chrystalline and Amorphous Material in the Clay Fraction of Ten Hawaiian Soils

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    The ability to measure the amount and composition of amorphous material in the clay fraction of soils offers opportunities for discovering the roles that these materials play in influencing soil behavior and performance. An objective of this research was to develop a methodology for the determination of the crystalline phase concentrations and the total amorphous material by the Rietveld method for ten agriculturally important Hawaiian soils. The oxide composition of the amorphous material was estimated by difference after the assignment of oxides found by X-ray fluorescence were allocated to the crystalline phases. A large disparity was found between the total amorphous material determined by the Rietveld method and the amorphous material determined by oxalate extraction, possibly because the two methods are reporting different portions of the clay fraction. For the first time correct crystalline phase concentrations can be determined because reliable estimates of the total amorphous material can be made

    A Nonlinear Offset Program to Reduce Nitrous Oxide Emissions Induced by Excessive Nitrogen Application

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    On average, U.S. farmers choose to apply nitrogen fertilizer at a rate that exceeds the ex post agronomically optimal rate. The technology underlying the yield response to nitrogen rewards producers who over apply in years when rainfall is excessive. The overapplication of nutrients has negative environmental consequences because the nitrogen that is not taken up by the plant will typically volatilize causing N2O emissions, or leach causing water pollution. We present a nonlinear offset program that induces farmers to reduce their nitrogen applications to the level that will be consumed by the plant in a typical year and, as a result, reduce N2O emissions from agriculture. The offset program is nonlinear because of the nonlinear relationship between N2O and nitrogen application rates. We assume that the farmer solves an expected utility maximization problem, choosing the optimal nitrogen application rate. The key contribution is a set of simulations that shows that modest offset payments will induce participation in the program and will have a significant impact on both expected and actual N2O emissions without having a significant impact on actual or expected yields. We also find that more risk-averse farmers will reduce emissions by a greater amount than less risk-averse farmers. Finally, we show the distribution of emission reductions induced by this nonlinear offset scheme.nitrogen fertilizer; carbon offsets; nitrous oxide; pollution; uncertainty.
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