5,866 research outputs found
Evaluation of power generation operations in response to changes in surface water reservoir storage
We used a customized, river basin-based model of surface water rights to evaluate the response
of power plants to drought via simulated changes in reservoir storage. Our methodology
models surface water rights in 11 river basins in Texas using five cases: (1) storage decrease of
existing capacity of 10%, (2) storage decrease of 50%, (3) complete elimination of storage,
(4) storage increase of 10% (all at existing locations), and (5) construction of new reservoirs
(at new locations) with a total increase in baseline reservoir capacity for power plant cooling
of 9%. Using the Brazos River basin as a sample, we evaluated power generation operations in
terms of reliability, resiliency, and vulnerability. As simulated water storage decreases,
reliability generally decreases and resiliency and vulnerability remain relatively constant. All
three metrics remain relatively constant with increasing reservoir storage, with the exception
of one power plant. As reservoir storage changes at power plants, other water users in the
basin are also affected. In general, decreasing water storage is beneficial to other water users
in the basin, and increasing storage is detrimental for many other users. Our analysis reveals
basin-wide and individual power plant-level impacts of changing reservoir storage,
demonstrating a methodology for evaluation of the sustainability and feasibility of
constructing new reservoir storage as a water and energy management approach.Mechanical Engineerin
Power Corrections to Fragmentation Functions in Non-Singlet Deep Inelastic Scattering
We investigate the power-suppressed corrections to the fragmentation
functions of the current jet in non-singlet deep inelastic lepton-hadron
scattering. The current jet is defined by selecting final-state particles in
the current hemisphere in the Breit frame of reference. Our method is based on
an analysis of one-loop Feynman graphs containing a massive gluon, which is
equivalent to the evaluation of leading infrared renormalon contributions. We
find that the leading corrections are proportional to , as in
annihilation, but their functional forms are different. We give quantitative
estimates based on the hypothesis of universal low-energy behaviour of the
strong coupling.Comment: 14 pages, 4 figures, LaTeX2e, uses JHEP.cls (included) and epsfi
NHS Direct: consistency of triage outcomes
OBJECTIVES: To examine the consistency of triage outcomes by nurses using four types of computerised
decision support software in NHS Direct.
METHODS: 119 scenarios were constructed based on calls to ambulance services that had been
assigned the lowest priority category by the emergency medical dispatch systems in use. These
scenarios were presented to nurses working in four NHS Direct call centres using different computerised
decision support software, including the NHS Clinical Assessment System.
RESULTS: The overall level of agreement between the nurses using the four systems was âfairâ rather than
âmoderateâ or âgoodâ (k=0.375, 95% CI: 0.34 to 0.41). For example, the proportion of calls triaged
to accident and emergency departments varied from 22% (26 of 119) to 44% (53 of 119). Between
21% (25 of 119) and 31% (37 of 119) of these low priority ambulance calls were triaged back to the
999 ambulance service. No system had both high sensitivity and specificity for referral to accident and
emergency services.
CONCLUSIONS: There were large differences in outcome between nurses using different software systems
to triage the same calls. If the variation is primarily attributable to the software then standardising on a
single system will obviously eliminate this. As the calls were originally made to ambulance services and
given the lowest priority, this study also suggests that if, in the future, ambulance services pass such
calls to NHS Direct then at least a fifth of these may be passed back unless greater sensitivity in the
selection of calls can be achieved
Can switching fuels save water? A life cycle quantification of freshwater consumption for Texas coal-and natural gas-fired electricity
Thermal electricity generation is a major consumer of freshwater for cooling, fuel extraction and air
emissions controls, but the life cycle water impacts of different fossil fuel cycles are not well understood.
Much of the existing literature relies on decades-old estimates for water intensity, particularly regarding
water consumed for fuel extraction. This work uses contemporary data from specific resource basins and
power plants in Texas to evaluate water intensity at three major stages of coal and natural gas fuel cycles:
fuel extraction, power plant cooling and power plant emissions controls. In particular, the water intensity
of fuel extraction is quantified for Texas lignite, conventional natural gas and 11 unconventional natural
gas basins in Texas, including major second-order impacts associated with multi-stage hydraulic
fracturing. Despite the rise of this water-intensive natural gas extraction method, natural gas extraction
appears to consume less freshwater than coal per unit of energy extracted in Texas because of the high
water intensity of Texas lignite extraction. This work uses new resource basin and power plant level
water intensity data to estimate the potential effects of coal to natural gas fuel switching in Texasâ power
sector, a shift under consideration due to potential environmental benefits and very low natural gas
prices. Replacing Texasâ coal-fired power plants with natural gas combined cycle plants (NGCCs) would
reduce annual freshwater consumption in the state by an estimated 53 billion gallons per year, or 60% of
Texas coal powerâs water footprint, largely due to the higher efficiency of NGCCs.Mechanical Engineerin
Alien Registration- Webber, Elizabeth E. (Gardiner, Kennebec County)
https://digitalmaine.com/alien_docs/29161/thumbnail.jp
Prospects for Research on the Community of True Inspiration
Review of: The Inspirationists, 1714-1932, edited by Peter Hoehnle. London: Pickering and Chatto, 2015. 3 volume set
Interferometric tracking system for the tracking and data relay satellite
This report documents construction and testing of the Interferometric Tracking System project developed under the NASA SBIR contract NAS5-30313. Manuals describing the software and hardware, respectively entitled: 'Field Station Guide to Operations' and 'Field Station Hardware Manual' are included as part of this final report. The objective of this contract was to design, build, and operate a system of three ground stations using Very Long Baseline Interferometry techniques to measure the TDRS orbit. The ground stations receive signals from normal satellite traffic, store these signals in co-located computers, and transmit the information via phone lines to a central processing site which correlates the signals to determine relative time delays. Measurements from another satellite besides TDRS are used to determine clock offsets. A series of such measurements will ultimately be employed to derive the orbital parameters, yielding positions accurate to within 50 meters or possibly better
The Intensities of Cosmic Ray H and He Nuclei at ~250 MeV/nuc Measured by Voyagers 1 and 2 - Using these Intensities to Determine the Solar Modulation Parameter in the Inner Heliosphere and the Heliosheath Over a 40 Year Time Period
We have determined the solar modulation potential, phi, vs. time that is
observed at Voyager 1 and 2 from measurements of the H and He nuclei
intensities at a common energy of 250 MeVnuc. The H nuclei have a rigidity 0.7
GV, the He nuclei 1.4 GV. These measurements cover a 40 year time period, which
includes almost 4 cycles of solar 11 year sunspot variations, throughout the
inner heliosphere out to the HTS at distances of 95 AU and 85 AU, respectively
at V1 and V2, and then beyond in the heliosheath. Inside the HTS the modulation
potential vs. time curves at V1 and V2 show a very similar temporal structure
to those observed at the Earth. During a later period of maximum solar
modulation from 2000.0 to 2005.0 when V1 and V2 are in the outer heliosphere
between 60-94 AU, the main temporal features of the modulation potential curves
at all 3 locations match up with appropriate time delays at V1 and V2 if it is
assumed that spatially coherent structures are moving outward past V1 and V2,
with outward speeds of up to 700 Kms negative 1. After 2004.0 V1 and V2 are at
latitudes of positive 35 and negative 30 respectively, placing lower limits on
the latitude extent of these structures. Beyond the HTS in the heliosheath the
modulation potential slowly decreases at both spacecraft with only a weak
evidence of the unusual modulation minimum observed at the Earth in 2009, for
example. A sudden decrease of the modulation potential 50 MV for both H and He
nuclei occurs at V1 just before the heliopause crossing at about 122 AU. This
decrease has not yet been observed at V2, which is now at 113 AU and still
observing a modulation potential 60 MV.Comment: 28 pages, 9 Figure
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