33,622 research outputs found

    Improved sampling of compressed gases for condensable hydrocarbon content

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    Sampling process was developed which uses commercially available high pressure filters and provides measurements in fraction of time required by older methods. Measurements show no significant difference in results between low pressure and high pressure samples. Filter method is slightly more accurate than scrubber technique

    Hyperswitch communication network

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    The Hyperswitch Communication Network (HCN) is a large scale parallel computer prototype being developed at JPL. Commercial versions of the HCN computer are planned. The HCN computer being designed is a message passing multiple instruction multiple data (MIMD) computer, and offers many advantages in price-performance ratio, reliability and availability, and manufacturing over traditional uniprocessors and bus based multiprocessors. The design of the HCN operating system is a uniquely flexible environment that combines both parallel processing and distributed processing. This programming paradigm can achieve a balance among the following competing factors: performance in processing and communications, user friendliness, and fault tolerance. The prototype is being designed to accommodate a maximum of 64 state of the art microprocessors. The HCN is classified as a distributed supercomputer. The HCN system is described, and the performance/cost analysis and other competing factors within the system design are reviewed

    Surface-gravity determinations for main-sequence B stars

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    Astronomical models for computing surface gravity of B stars from hydrogen line equivalent width

    USING MECHANICAL TRADING SYSTEMS TO EVALUATE THE WEAK FORM EFFICIENCY OF FUTURES MARKETS

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    Research and Development/Tech Change/Emerging Technologies,

    Groundwater Use under Incomplete Information

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    In this paper, we introduce a game theoretic model of groundwater extraction in a two-cell aquifer under incomplete information. A novel assumption is that individual users have incomplete knowledge of the speed of lateral flows in the aquifer: although a user is aware that his neighbor's water use has some influence on their future water stock, they are uncertain about the degree of this impact. We find that the lack of information may either increase or decrease the rate of water use and welfare. In a two-period framework, the relevant characteristic is the ratio of the periodic marginal benefits of water use. Depending on whether this ratio is convex or concave, the average speed with which the aquifer is depleted decreases or increases when users learn more about the local hydrologic properties of groundwater. We also show that the effect of better information on the welfare of the average producer may be negative even in the situations when, on average, groundwater is allocated more efficiently across irrigation seasons.Resource /Energy Economics and Policy,

    Groundwater Pumping by Heterogeneous Users

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    Farm size is a significant determinant of both groundwater irrigated farm acreage and groundwater irrigation application rates per acre. This paper analyzes the patterns of groundwater exploitation when resource users in the area overlying a common aquifer are heterogeneous. In the presence of user heterogeneity, the common resource problem consists of inefficient dynamic and spatial allocation of groundwater because it impacts income distribution not only across periods but also across farmers. Under competitive allocation, smaller farmers pump groundwater faster if farmers have a constant marginal periodic utility of income. However, it is possible that larger farmers pump faster if the Arrow-Pratt coefficient of relative risk-aversion is sufficiently decreasing in wealth. A greater farm-size inequality may either moderate or amplify income inequality among farmers. Its effect on welfare depends on the curvature properties of the agricultural output function and the farmer utility of income. Also, it is shown that a flat-rate quota policy that limits the quantity of groundwater extraction per unit land may have unintended consequences for the income distribution among farmers.common property resource, groundwater, majorization, Resource /Energy Economics and Policy,

    The economic value of remote sensing of earth resources from space: An ERTS overview and the value of continuity of service. Volume 5: Inland water resources

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    The economic value of an ERTS system in the area of inland water resources management is investigated. Benefits are attributed to new capabilities for managing inland water resources in the field of power generation, agriculture, and urban water supply. These benefits are obtained in the area of equal capability (cost savings) and increased capability (equal budget), and are estimated by applying conservative assumptions to Federal budgeting information, Congressional appropriation hearings, and ERTS technical capabilities

    Rotorcraft digital advanced avionics system (RODAAS) functional description

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    A functional design of a rotorcraft digital advanced avionics system (RODAAS) to transfer the technology developed for general aviation in the Demonstration Advanced Avionics System (DAAS) program to rotorcraft operation was undertaken. The objective was to develop an integrated avionics system design that enhances rotorcraft single pilot IFR operations without increasing the required pilot training/experience by exploiting advanced technology in computers, busing, displays and integrated systems design. A key element of the avionics system is the functionally distributed architecture that has the potential for high reliability with low weight, power and cost. A functional description of the RODAAS hardware and software functions is presented

    Stability of the Submillimeter Brightness of the Atmosphere Above Mauna Kea, Chajnantor and the South Pole

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    The summit of Mauna Kea in Hawaii, the area near Cerro Chajnantor in Chile, and the South Pole are sites of large millimeter or submillimeter wavelength telescopes. We have placed 860 GHz sky brightness monitors at all three sites and present a comparative study of the measured submillimeter brightness due to atmospheric thermal emission. We report the stability of that quantity at each site.Comment: 6 figure

    Diagnostics of the structure of AGN's broad line regions with reverberation mapping data: confirmation of the two-component broad line region model

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    We re-examine the ten Reverberation Mapping (RM) sources with public data based on the two-component model of the Broad Line Region (BLR). In fitting their broad H-beta lines, six of them only need one Gaussian component, one of them has a double-peak profile, one has an irregular profile, and only two of them need two components, i.e., a Very Broad Gaussian Component (VBGC) and an Inter-Mediate Gaussian Component (IMGC). The Gaussian components are assumed to come from two distinct regions in the two-component model; they are Very Broad Line Region (VBLR) and Inter-Mediate Line region (IMLR). The two sources with a two-component profile are Mrk 509 and NGC 4051. The time lags of the two components of both sources satisfy tIMLR/tVBLR=VVBLR2/VIMLR2t_{IMLR}/t_{VBLR}=V^2_{VBLR}/V^2_{IMLR}, where tIMLRt_{IMLR} and tVBLRt_{VBLR} are the lags of the two components while VIMLRV_{IMLR} and VVBLRV_{VBLR} represent the mean gas velocities of the two regions, supporting the two-component model of the BLR of Active Galactic Nuclei (AGN). The fact that most of these ten sources only have the VBGC confirms the assumption that RM mainly measures the radius of the VBLR; consequently, the radius obtained from the R-L relationship mainly represent the radius of VBLR. Moreover, NGC 4051, with a lag of about 5 days in the one component model, is an outlier on the R-L relationship as shown in Kaspi et al. (2005); however this problem disappears in our two-component model with lags of about 2 and 6 days for the VBGC and IMGC, respectively.Comment: 7 pages, 5 figures. Accepted for publication in the Special Issue of Science in China (G) "Astrophysics of Black holes and Related Compact Objects
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