4,499 research outputs found

    Development of electrical test procedures for qualification of spacecraft against EID. Volume 1: The CAN test and other relevant data

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    A combined experimental and analytical program to develop system electrical test procedures for the qualification of spacecraft against damage produced by space-electron-induced discharges (EID) occurring on spacecraft dielectric outer surfaces is described. The data on the response of a simple satellite model, called CAN, to electron-induced discharges is presented. The experimental results were compared to predicted behavior and to the response of the CAN to electrical injection techniques simulating blowoff and arc discharges. Also included is a review of significant results from other ground tests and the P78-2 program to form a data base from which is specified those test procedures which optimally simulate the response of spacecraft to EID. The electrical and electron spraying test data were evaluated to provide a first-cut determination of the best methods for performance of electrical excitation qualification tests from the point of view of simulation fidelity

    High resolution, low temperature photoabsorption cross-section of C2H2 with application to Saturn's atmosphere

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    New laboratory observations of the VUV absorption cross-section of C2H2, obtained under physical conditions approximating stratospheres of the giant planets, were combined with IUE observations of the albedo of Saturn, for which improved data reduction techniques have been used, to produce new models for that atmosphere. When the effects of C2H2 absorption are accounted for, additional absorption by other molecules is required. The best-fitting model also includes absorption by PH3, H2O, C2H6 and CH4. A small residual disagreement near 1600 A suggests that an additional trace species may be required to complete the model

    The Age Context of Performance Evaluation Decisions

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    Organizational demography contends that demographic characteristics of individuals, examined at individual, dyadic, group, and organizational levels of analysis, exert significant effects on organizational processes. The purpose of this paper was to test the contextual effects created by the interaction of work group age composition and supervisor age on supervisor evaluations of subordinate performance. Two competing models of age demography were tested. The similarity model predicts that supervisors similar in age to the work group they supervise will issue generally higher performance ratings. The dissimilarity model developed in this paper predicts the opposite. Support was indicated for the dissimilarity model. Implications of the results are discussed

    Spatial Analyses of the Meat Marketing Sector in 1955 and 1960

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    The livestock products sector is a complex composed of the activities of production, farm marketing, slaughtering, distribution and consumption. The level of each of these activities varies spatially and thus regional imbalances are generated which make necessary product flows between the geographical areas. Within this setting this study is concerned with an interregional analysis of the livestock meat sector of the U. S. economy. Thus, spatial slaughter-consumption relations will be basic observations for this analysis. In this study regional demands are reflected by price dependent demand relations or specific estimates of consumption. Regional supplies are dressed carcass weights of livestock slaughter within the regions. In particular for the beef, pork, veal, and lamb and mutton sectors for the years 1955 and 1960 answers will be sought to the following questions: 1. What are the levels of regional demand for each of these meat products? 2. What are the levels of regional supply for each of these products? 3. What is the aggregate interregional trade for each meat product for each year? 4. For each commodity and for each year, what regions import, export or do neither? 5. What are the levels of regional exports and imports for each region, commodity and year? 6. What is the optimum volume and direction of trade between all possible pairs of regions for each commodity and each year? 7. What are the optimum price differentials between regions for each commodity and year? 8. What is the total transport cost for the aggregate trade of each commodity and year? 9. What is the impact of alternative ways of estimating regional meat consumption on the interregional flows and price differentials? In the following pages the results that are generated by these questions will be given and the implications and uses of the results will be discussed

    Spatial Analyses of the Flow of Slaughter Livestock in 1955 and 1960

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    In this study attention is focused on the spatial aspects of slaughter livestock movements from production to slaughtering. Given the regional levels of production, slaughtering and the costs of moving one unit of various types of slaughter livestock from any one region to another region, this study is concerned with ascertaining the regional price differentials, and the volume and direction of regional imports and exports that are consistent with minimizing the total cost of moving the livestock from production to slaughter. In addition, questions about the consequences of changes in the existing structure of the livestock economy may be evaluated with regard to their impact on regional prices and slaughter livestock flows

    Joint Spatial Analysis of Regional Slaughter and the Flows and Pricing of Livestock and Meat

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    The purpose of this study is to (1) develop a model to handle the simultaneous solution for the processing and flow problem, (2) develop estimates of slaughtering capacity for cattle and hogs in each region, and (3) apply the model using estimates of regional levels of production, regional levels of consumption, regional slaughtering capacities, and transportation costs of live slaughter animals and meats. Attention is focused at determining what regional levels of slaughter and directions and levels of interregional livestock and meat flows satisfy the regional production consumption, and capacity constraints and make the total cost of transportation of live slaughter animals and meat a minimum. The analysis is broadened to also obtain the impacts of alternative regional slaughter capacity restrictions and .regional differences in the labor cost of slaughtering livestock

    Assessing Alkali-Metal Effects in the Structures and Reactivity of Mixed-Ligand Alkyl/Alkoxide Alkali-Metal Magnesiates

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    Advancing the understanding of using alkali‐metal alkoxides as additives to organomagnesium reagents in Mg−Br exchange reactions, a homologous series of mixed‐ligand alkyl/alkoxide alkali‐metal magnesiates [MMg(CH(2)SiMe(3))(2)(dmem)](2) [dmem=2‐{[2‐(dimethylamino)ethyl]methylamino} ethoxide; M=Li, 1; Na, 2; (THF)K, 3] has been prepared. Structural and spectroscopic studies have established the constitutions of these heteroleptic/heterometallic species, which are retained in arene solution. Evaluation of their reactivity towards 2‐bromoanisole has uncovered a marked alkali‐metal effect with potassium magnesiate 3 being the most efficient of the three ate reagents. Studies probing the constitution of the exchange product from this reaction suggest that the putative [KMgAr(2)(dmem)](2) (Ar=o‐OMe−C(6)H(4)) intermediate undergoes redistribution into its single metal components [KAr](n) and [MgAr(dmem)](2) (5). This process can be circumvented by using a different potassium alkoxide containing an aliphatic chain such as KOR’ (R’=2‐ethylhexyl) which undergoes co‐complexation with Mg(CH(2)SiMe(3)) to give [KMg(CH(2)SiMe(3))(2)(OR’)](2) (7). This ate, in turn, reacts quantitatively with 2‐bromoanisole furnishing [KMgAr(2)(OR’)](2) (9) which is stable in solution as a bimetallic compound. Collectively this work highlights the complexity of these alkali‐metal mediated Mg−Br exchange reactions, where each reaction component can have a profound effect not only on the success of the reaction; but also the stability of the final metalated intermediates prior to their electrophilic interception
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