74,817 research outputs found

    A rocket-borne data-manipulation experiment using a microprocessor

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    The development of a data-manipulation experiment using a Z-80 microprocessor is described. The instrumentation is included in the payloads of two Nike Apache sounding rockets used in an investigation of energetic particle fluxes. The data from an array of solid-state detectors and an electrostatic analyzer is processed to give the energy spectrum as a function of pitch angle. The experiment performed well in its first flight test: Nike Apache 14.543 was launched from Wallops Island at 2315 EST on 19 June 1978. The system was designed to be easily adaptable to other data-manipulation requirements and some suggestions for further development are included

    Advanced Computer Dormant Reliability Study Final Report

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    Reliability of integrated circuits and discrete components of electronics for computer and dormant module for Minuteman

    Evidence from scanning tunneling microscopy in support of a structural model for the InSb(001)-c(8Ă—2) surface

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    In this letter we present evidence from scanning tunneling microscopy studies in support of a recently proposed structural model for the indium-terminated c(8×2) surface of InSb(001). This structural model, by Norris and co-workers, is based on a surface x-ray diffraction study [Surf. Sci. 409, 27 (1998)], and represents a significant departure from previously suggested models for the c(8×2) reconstruction on any (001) surface of the common III–V semiconductor materials. Although filled state images of the InSb(001)-c(8×2) surface have previously been published, empty states image of sufficient quality to extract any meaningful information have not previously been reported. The observations are in excellent agreement with the recently proposed model for this surface reconstruction

    Pressures and Preferences Affecting Willingness to Apply Beef Manure on Crops in the Colorado High Plains

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    Little is known about producers' willingness to use manure. Past studies have focused on substitutability for fertilizers. We surveyed crop producers in a cattle-dense region of the Colorado Plains about whether and why they apply manure, focusing on how pressures (like owning cattle) or preferences (pro and con) affect their adoption. Using logistic regression, findings show that pressure and preference (PS/PF) significantly affect adoption. A producer with high PS/PF was 10 times more likely to use manure than one with low PS/PF. Policy and decision makers can use such findings to inform education and policy aimed at increasing the land application of manure.cattle, economic benefits, economic costs, management, manure application, Crop Production/Industries,

    Structural concepts for hydrogen-fueled hypersonic airplanes

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    Structural concepts for hydrogen-fueled hypersonic aircraf

    United States Trade Flows for Selected Categories of Specialty Crops

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    Nationally, Florida ranked second in farm cash receipt from all crops and second, based on value, in vegetable production (USDA, 2003). It also ranked fourteenth out of all the states with respect to agricultural exports with its top exports, fruits and vegetables, falling within the category of specialty crops. According to the USDA (2003), Florida's agricultural exports helped to boost farm prices and income and supported approximately 17,000 jobs both on and off farm in 2001. As such, its agricultural exports are important to Florida's agricultural and statewide economy. From a Florida farm cash receipts perspective, increased imports could undermine revenue earnings from specialty crop production, especially if there is not a comparable growth in the exports of these crops. This report covered the period 1991 to 2002 and examined trade flows for selected specialty crops deemed important to Florida's agriculture. Overall, the US had a relatively high import level of the selected specialty crops. This was apparent from the widening trade gaps and the declining surpluses experienced by all commodities, with the exception of oranges and strawberries. CANMEX was the dominant supplier of vegetables, and growing imports from this group drove the growing vegetable trade deficit. With respect to fruits, CANMEX was also a dominant supplier and affected trade balances however, many of the declining fruit trade balances were due to declining exports to markets such as Asia and the Europe. CANMEX played a major role in the trade of foliage and floriculture but did not dominate the trade. Over the period 1991 to 2002 there were changes in the trade flows of the selected vegetables, fruits and foliage and floriculture. Two noticeable trends were the concentration of trade with CANMEX, especially with respect to vegetable exports and declining exports to Asia and Europe. Also noticeable were declining trade balances experienced by the majority of the commodities in this study. With free trade agreements, an increased inflow of goods is expected as trade barriers are lowered. Preparing for additional imports resulting from expanded regional free trade agreements in the western hemisphere requires the commitment of additional resources toward the expansion of existing markets and the development of potentially new markets.Crop Production/Industries, International Relations/Trade,

    Development of a portable precision landing system

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    A portable, tactical approach guidance (PTAG) system, based on a novel, X-band, precision approach concept, was developed and flight tested as a part of NASA's Rotorcraft All-Weather Operations Research Program. The system is based on state-of-the-art X-band technology and digital processing techniques. The PTAG airborne hardware consists of an X-band receiver and a small microprocessor installed in conjunction with the aircraft instrument landing system (ILS) receiver. The microprocessor analyzes the X-band, PTAG pulses and outputs ILS compatible localizer and glide slope signals. The ground stations are inexpensive, portable units, each weighing less than 85 lb, including battery, that can be quickly deployed at a landing site. Results from the flight test program show that PTAG has a significant potential for providing tactical aircraft with low cost, portable, precision instrument approach capability

    Invoices, Linwood Davis, 1903-1906

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    Miscellaneous invoices for Linwood Davis, B. Davis, Mansfield Davis, L.A. Davis and G. Davis for various fishing supplies, including fish barrels, quantities of salt, saltfish and a dory from businesses in Vinalhaven (Me.), Friendship (Me.) and Boothbay Harbor (Me.)
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