3,035 research outputs found
A summary of NASA data relative to external-store separation characteristics
Aerodynamic characteristics of external stores in carriage position and their effect on separation characteristics under various delivery condition
Modeling water resources management at the basin level: review and future directions
Water quality / Water resources development / Agricultural production / River basin development / Mathematical models / Simulation models / Water allocation / Policy / Economic aspects / Hydrology / Reservoir operation / Groundwater management / Drainage / Conjunctive use / Surface water / GIS / Decision support systems / Optimization methods / Water supply
Integrated economic-hydrologic water modeling at the basin scale: the Maipo river basin
Increasing competition for water across sectors increases the importance of the river basin as the appropriate unit of analysis to address the challenges facing water resources management; and modeling at this scale can provide essential information for policymakers in their resource allocation decisions. This paper introduces an integrated economic-hydrologic modeling framework that accounts for the interactions between water allocation, farmer input choice, agricultural productivity, nonagricultural water demand, and resource degradation in order to estimate the social and economic gains from improvement in the allocation and efficiency of water use. The model is applied to the Maipo River Basin in Chile. Economic benefits to water use are evaluated for different demand management instruments, including markets in tradable water rights, based on production and benefit functions with respect to water for the agricultural and urban-industrial sectors.Resource allocation., Water resources development Chile., Chile.,
Deep space payload launches via the Space Transportation System
The launching of deep space payloads via the Space Shuttle vehicle of the Space Transportation System, rather than via expendable launch vehicles, is described. Changes in procedures and data flow configurations for both the flight project and DSN during the launch period are required. A typical Galileo launch period sequence of events and telemetry and command data flow configurations are described
Predicting Malawian women’s intention to adhere to antiretroviral therapy
Background. With the increase in scaling up of antiretroviral therapy (ART), knowledge of the need for adherence to ART is pivotal for successful treatment outcomes. Design and Methods. A cross-sectional study was carried out between October and December 2013. We administered theory of planned behaviour (TPB) and adherence questionnaires to 358 women aged 18-49 years, from a rural and urban ART-clinics in southern Malawi. Hierarchical linear regression models were used to predict intentions to adhere to ART. Results. Regression models showed that attitude (β=0.47), subjective norm (β=0.31), and perceived behavioral control (β=0.12) explain 55% of the variance in intentions to adhere to ART. The relationship between both food insecurity and perceived side effects with intentions to adhere to ART is mediated by attitude, subjective norm, and perceived behavioural control. Household (r=0.20) and individual (r=0.21) food insecurity were positively and significantly correlated with perceived behavioural control. Household food insecurity had a negative correlation with perceived side effects (r=-0.11). Perceived side effects were positively correlated with attitude (r=0.25). There was no statistically significant relationship between intentions to adhere to ART in the future and one month self-report of past month adherence. These interactions suggest that attitude predicted adherence only when food insecurity is high or perception of side effects is strong.Conclusions. This study shows that modification might be needed when using TPB constructs in resource constraint environment
Measuring Black Hole Spin by the Continuum-Fitting Method: Effect of Deviations from the Novikov-Thorne Disc Model
The X-ray spectra of accretion discs of eight stellar-mass black holes have
been analyzed to date using the thermal continuum fitting method, and the
spectral fits have been used to estimate the spin parameters of the black
holes. However, the underlying model used in this method of estimating spin is
the general relativistic thin-disc model of Novikov & Thorne, which is only
valid for razor-thin discs. We therefore expect errors in the measured values
of spin due to inadequacies in the theoretical model. We investigate this issue
by computing spectra of numerically calculated models of thin accretion discs
around black holes, obtained via three-dimensional general relativistic
magnetohydrodynamic (GRMHD) simulations. We apply the continuum fitting method
to these computed spectra to estimate the black hole spins and check how
closely the values match the actual spin used in the GRMHD simulations. We find
that the error in the dimensionless spin parameter is up to about 0.2 for a
non-spinning black hole, depending on the inclination. For black holes with
spins of 0.7, 0.9 and 0.98, the errors are up to about 0.1, 0.03 and 0.01
respectively. These errors are comparable to or smaller than those arising from
current levels of observational uncertainty. Furthermore, we estimate that the
GRMHD simulated discs from which these error estimates are obtained correspond
to effective disc luminosities of about 0.4-0.7 Eddington, and that the errors
will be smaller for discs with luminosities of 0.3 Eddington or less, which are
used in the continuum-fitting method. We thus conclude that use of the
Novikov-Thorne thin-disc model does not presently limit the accuracy of the
continuum-fitting method of measuring black hole spin.Comment: 13 pages, 7 figures, accepted for publication in MNRAS. v2: fixed
typo in author name, updated acknowledgment
Design, analysis and test verification of advanced encapsulation systems, phase 2 program results
Optical, electrical isolation, thermal structural, structural deflection, and thermal tests are reported. The utility of the optical, series capacitance, and structural deflection models was verified
A PC parallel port button box provides millisecond response time accuracy under Linux
For psychologists, it is sometimes necessary to measure people's reaction times to the nearest millisecond. This article describes how to use the PC parallel port to receive signals from a button box to achieve millisecond response time accuracy. The workings of the parallel port, the corresponding port addresses, and a simple Linux program for controlling the port are described. A test of the speed and reliability of button box signal detection is reported. If the reader is moderately familiar with Linux, this article should provide sufficient instruction for him or her to build and test his or her own parallel port button box. This article also describes how the parallel port could be used to control an external apparatus
Comparison of 35 and 50 {\mu}m thin HPK UFSD after neutron irradiation up to 6*10^15 neq/cm^2
We report results from the testing of 35 {\mu}m thick Ultra-Fast Silicon
Detectors (UFSD produced by Hamamatsu Photonics (HPK), Japan and the comparison
of these new results to data reported before on 50 {\mu}m thick UFSD produced
by HPK. The 35 {\mu}m thick sensors were irradiated with neutrons to fluences
of 0, 1*10^14, 1*10^15, 3*10^15, 6*10^15 neq/cm^2. The sensors were tested
pre-irradiation and post-irradiation with minimum ionizing particles (MIPs)
from a 90Sr \b{eta}-source. The leakage current, capacitance, internal gain and
the timing resolution were measured as a function of bias voltage at -20C and
-27C. The timing resolution was extracted from the time difference with a
second calibrated UFSD in coincidence, using the constant fraction method for
both. Within the fluence range measured, the advantage of the 35 {\mu}m thick
UFSD in timing accuracy, bias voltage and power can be established.Comment: 9 pages, 9 figures, HSTD11 Okinawa. arXiv admin note: text overlap
with arXiv:1707.0496
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