5,904 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
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
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
Alien Registration- Webber, Elizabeth E. (Gardiner, Kennebec County)
https://digitalmaine.com/alien_docs/29161/thumbnail.jp
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
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
Teaching natural resources policy through case studies, authentic assessment and the internet
The teaching of natural resources and environmental policy does not lend itself well to the traditional methods of teaching found in the field of natural resources. Instead, a teaching triangle composed of methods from the social sciences and the application of technology allow for a more complete and thorough understanding of the subject by the student. Use of case studies forms the basis of this teaching method, removing the abstractness of the subject and showing the actual field application of what is taught. Authentic assessment or reliable evaluation methods expand the students thinking on the subject while giving the instructor a solid indicator of student learning. Finally, the Internet and the use of a listserve provide information access and instructor-student interaction not possible before
The Elemental Composition of Quiet Time Low Energy Cosmic Rays Measured on the Voyager Spacecraft
We have used the large collecting area of the Voyager telescopes to obtain greatly improved statistics on the elemental composition of quiet time low energy cosmic rays above ~3MeV/nuc. Three quiet time
periods totaling 115 days between August, 1977 and February, 1978 are
used. These quiet times are further subdivided into still quieter
periods totaling 47 days. At low energies, the most prominent feature
is the anomalous component which has a peak intensity at ~6 MeV/nuc.
It is observed most prominently for N, 0 and Ne nuclei, but we believe
it has been identified for the first time for C, Mg and Si nuclei as
well at a much lower intensity level. This component undergoes strong
solar modulation effects, and also for 0 nuclei at least, shows 27 day
enhancements associated with enhanced intensities of ~0.5 MeV proton
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