601 research outputs found
Review and Evaluation of the Gibson Dome High Level Nuclear Waste Repository Environmental Assessment: Geohydrologic Issues
Introduction: Background/Authorization: This report is meant to provide a technical review and evaluation of Department of Energy documents concerning groundwater, radionuclide travel time and monitoring issues relative to siting a high level nuclear waste repository in the Gibson Dome area in Southern Utah. in so doing we have, during a relatively short period of time, examined in detail the Department of Energy Guidelines concerning high level nuclear waste disposal (1983) including revisions (1984), and each draft of the Environmental Assessments for Davis and Lavender Canyon, up to and including the fifth draft (dated July 27, 1984). In addition, a large body of supporting DOE documents and relavant published research literature was carefully examined and incorporated into this report. Our approach to the review and evaluation process has been to examine the assumptions analysis procedures, conclusions and supporting data regarding groundwater, radionuclide travel time and monitoring issues for the Davis and Lavender Canyon Environmental Assessments, and to provide independent appraisal of the DOE approach and assessment of these issues. This work is carried out under a contract with the State of Utah Office of Planning and Budget (Contract No. 85-0205)
A cost comparison of traditional drainage and SUDS in Scotland
The Dunfermline Eastern Expansion (DEX) is a 350 ha mixed development which commenced in 1996. Downstream water quality and flooding issues necessitated a holistic approach to drainage planning and the site has become a European showcase for the application of Sustainable Urban Drainage Systems (SUDS). However, there is minimal data available regarding the real costs of operating and maintaining SUDS to ensure they continue to perform as per their design function. This remains one of the primary barriers to the uptake and adoption of SUDS. This paper reports on what is understood to be the only study in the UK where actual costs of constructing and maintaining SUDS have been compared to an equivalent traditional drainage solution. To compare SUDS costs with traditional drainage, capital and maintenance costs of underground storage chambers of analogous storage volumes were estimated. A whole life costing methodology was then applied to data gathered. The main objective was to produce a reliable and robust cost comparison between SUDS and traditional drainage. The cost analysis is supportive of SUDS and indicates that well designed and maintained SUDS are more cost effective to construct, and cost less to maintain than traditional drainage solutions which are unable to meet the environmental requirements of current legislation
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Scientific evidence to support the art of prescribing spectacles. Identification of the clinical scenarios in which optometrists apply partial prescribing techniques and the quantification of spectacle adaption problems.
Although experiential prescribing maxims are quoted in some optometric
textbooks their content varies significantly and no direct research evidence
was available to support their use. Accordingly in chapters 2 and 3, the
uses of several potential prescribing rules were investigated in the UK
optometric profession. Our results indicated that the subjective refraction
result exerted a strong hold on the prescribing outcome with 40-85% of
optometrists prescribing the subjective result in a variety of scenarios. The
finding that after 40 years qualified, experienced optometrists were three
times more likely to suggest a partial prescription was an important
discovery that provides significant support for the prescribing rules
suggested by various authors. It would also appear from the results of the
retrospective evaluation of the ¿if it ain¿t broke, don¿t fix it¿ clinical maxim in
Chapter 4 that spectacle dissatisfaction rates could be reduced by
between 22 to 42% depending on how strictly the maxim is interpreted by
the practitioner. Certainly an ¿if it ain¿t broke, don¿t fix it much¿ maxim was
suggested as being particularly appropriate. Chapter 5 included a reanalysis
of previously published data that found no change in falls rate
after cataract surgery to investigate any influence of refractive correction
change and /or visual acuity change on falls rate. Unfortunately these data
were not sufficiently powered to provide significant results. In chapter 6, a
spectacle adaptation questionnaire (SAQ) was developed and validated
using Rasch analysis. Initial studies found no differences in SAQ with
gender or age.College of Optometrist
Contemplating Mindfulness at Work: An Integrative Review
Mindfulness research activity is surging within organizational science. Emerging evidence across multiple fields suggests that mindfulness is fundamentally connected to many aspects of workplace functioning, but this knowledge base has not been systematically integrated to date. This review coalesces the burgeoning body of mindfulness scholarship into a framework to guide mainstream management research investigating a broad range of constructs. The framework identifies how mindfulness influences attention, with downstream effects on functional domains of cognition, emotion, behavior, and physiology. Ultimately, these domains impact key workplace outcomes, including performance, relationships, and well-being. Consideration of the evidence on mindfulness at work stimulates important questions and challenges key assumptions within management science, generating an agenda for future research
Thermodynamic limits on oxygenic photosynthesis around M-dwarf stars: Generalized models and strategies for optimization
We explore the feasibility and potential characteristics of photosynthetic
light-harvesting on exo-planets orbiting in the habitable zone of low mass
stars ( M). As stellar temperature, , decreases, the
irradiance maximum red-shifts out of the
nm range of wavelengths that can be utilized by \emph{oxygenic} photosynthesis
on Earth. However, limited irradiance in this region does not preclude oxygenic
photosynthesis and Earth's plants, algae and cyanobacteria all possess very
efficient \emph{light-harvesting antennae} that facilitate photosynthesis in
very low light. Here we construct general models of photosynthetic
light-harvesting structures to determine how an oxygenic photosystem would
perform in different irradiant spectral fluxes. We illustrate that the process
of light-harvesting, capturing energy over a large antenna and concentrating it
into a small \emph{reaction centre}, must overcome a fundamental \emph{entropic
barrier}. We show that a plant-like antenna cannot be adapted to the light from
stars of K, as increasing antenna size offers diminishing returns
on light-harvesting. This can be overcome if one introduces a slight
\emph{enthalpic gradient}, to the antenna. Interestingly, this strategy appears
to have been adopted by Earth's oxygenic cyanobacteria, and we conclude that
\emph{bacterial} oxygenic photosynthesis is feasible around even the lowest
mass M-dwarf stars.Comment: 5 Figures, submitted to Astrobiology and awaiting return of revie
Management of Groundwater Recharge Areas in the Mouth of Weber Canyon
Proper management of surface and groundwater resources is important for their prolonged and a beneficial use. Within the Weber Delta area there has existed a continual decline in the piezometric surface of the deep confined aquifer over the last 40 years. This decline ranges from approximately 20 feet along the eastern shore of the Great Salt Lake to 50 feet along in the vicinity of Hill Air Force Base. Declines in the piezometric surface are undesirable because of the increased well installation costs, increased pumping costs, decreased aquifer storage, increased risk of salt water intrusion, and the possibility of land subsidence. Declines in the piezometric surface can be prevented or reduced by utilizing artificial groundwater recharge. The purpose of this study was to develop and operate a basin groundwater model with stochastic recharge inputs to determine the feasibility of utilizing available Weber River water for the improvement of the groundwater availability. This was accomplished by preparing auxiliary computer models which generated statistically similar river flows from which river water rights were subtracted. The feasibility of utilizing this type of recharge input was examined by comparing the economic benefit gained by reducing area wide pumping lifts through artificial recharge with the costs of the recharge operations. Institutions for implementing a recharge program were examined. Through this process a greater understanding of the geohydrologic conditions of the area was obtained. Piezometric surface contour maps, geologic profiles, calibrated values for geologic and hydrologic variables, as well as system response to change were quantified
Identification and Modeling the Impact of Marine Shale Bedrock on Groundwater and Stream Salinity: Upper Colorado River Basin
Recent studies have shown that groundwater is a major contributor to stream salinity in the Upper Colorado River Basin. The primary salt sources are the marine shales and shale residuum that underlie the soils of much of the basin. A field site in the Price River Basin, a tributary to the Green and Colorado Rivers, was selected to study the physical and chemical factors that control the interactions between groundwater and these shales. Preliminary data were available at the site as a result of a Bureau of Reclamation study conducted by CH2M Hill. On the basis of the CH2M Hill study and the additional data collected during this study groundwater flow paths, salt transport and weathering processes were identified. Results show that the groundwater evolved from a calcium-bicarbonate water to a sodium-sulfate water with depth and distance along the flow paths. Geochemical equilibrium modeling and mass balance computations were performed using the USGS models PHREEQE and BALANCE. A preliminary saturated-unsaturated two-dimensional flow model (UNSAT) was implemented along the identified groundwater flow path. Once a satisfactory flow calibration was achieved, a solute transport model was then implemented to examine the relative importance of advective, dispersive and diffusive mixing processes along the flow profile. Preliminary management runs were made to study the effect of possible changes in land use practices. Results of these hypothetical cases suggest that water conservation methods (improved irrigation efficiency, canal lining and retiring irrigated land) will reduce return flow salt loads over the short run (about 50 years), when the transport of salts by displacement is most important. However, these salinity control alternatives are much less effective in the long range (\u3e 50 years) because the diffuse salt loading from underlying marine shales is unaffected by groundwater flow rates in the alluvium. Although additional field data must be collected for verification the proposed model is a realistic first step towards a quantitative physically based approach to land use-salinity control issues
Bulk crystal growth and surface preparation of NiSb, MnSb, and NiMnSb
Bulk single crystal and polycrystalline samples of NiSb, MnSb, and NiMnSb have been grown and characterized. The lattice parameter of NiMnSb was found to be 5.945 ± 0.001 Å, around 0.25% larger than previous reports. The surface preparation of these materials was investigated using x-ray photoelectron spectroscopy. Wet etching with HCl and argon ion sputtering were used in tandem with vacuum annealing. For both binary materials, a clean and stoichiometric surface could be regained by HCl etching and annealing alone. However, clean and stoichiometric ternary NiMnSb was not successfully prepared by these methods. The transition metal 2p and 3p levels are analyzed for all three materials
Hydrologic Evaluation of the Coastal Belt Water Project Sarir and Tazerbo Well Fields, Libya
Executive Summary: The basic purpose of this study was to conduct a finite-element computer model and give an dindependent appraisal of the reliability of the groundwater supply for the proposed Coastal Belt Water Project (CBWP_ Well Fields at Sarir and Tazerbo. There is no doubt that ample quantities of groundwater of acceptable quality occur at the sites selected for these well fields for the estimated 50-year life of the project and longer. Of major concern is the predicted drawdown of wells and total pumping lifts throughout the 50-year period. Excessive drawdowns could cause operating costs to become prohibitibely expensive. Average drawdown in wells not including well-field interference and hydraulic friction losses at the CBWP Well Field at Sarir is expected to be only about 30 m at the end of 50 years, but the static water level is relatively deep (56 m) which makes the total pumping lift fairly high when well-field interference and other losses are added. This optimistic estimate of drawdown is based upon computer analysis for almost 7 years of pumping history of the existing Sarir South agricultural well field nearby, where the subsurface geology is believed to be quite similar to that at the propsed CBWP Well Field at Sarir. The average dpumping lift, which includes many other factors besides aquifer drawdown, is estimated to be about 142 m. at the end of the 50-year pumping period at Sarir and should average about 136 m during the 50 years. Interference from pumpage at the existing agricultural well fields at Sarir may be responsible for about 10 m of this predicted pumping lift. Drawdown at Tazerbo is predicted to be about 90 m. at the end of 50 years, but the static water level is only about 9 m. there. Consequently its average pumping lift should be about 133 m at the end of the 50-year pumping period and should average about 118 m during the 50 years. no appreciable interference from nearby well fields is expected in the Tazerbo area based upon presently known conditions. Significatn reductions in pumping lifts at Tazerbo and in water-collection network costs at Sarir are possible by improved well field layout and well design. Suggested inprovements and estimated cost savings are presented in detail in Appendix A (especially see well-field design comparisons of Tables A-1 and A-4)
Discontinuous metric programming in liquid crystalline elastomers
Liquid crystalline elastomers (LCEs) are shape-changing materials that
exhibit large deformations in response to applied stimuli. Local control of the
orientation of LCEs spatially directs the deformation of these materials to
realize spontaneous shape change in response to stimuli. Prior approaches to
shape programming in LCEs utilize patterning techniques that involve the
detailed inscription of spatially varying nematic fields to produce sheets.
These patterned sheets deform into elaborate geometries with complex Gaussian
curvatures. Here, we present an alternative approach to realize shape-morphing
in LCEs where spatial patterning of the crosslink density locally regulates the
material deformation magnitude on either side of a prescribed interface curve.
We also present a simple mathematical model describing the behavior of these
materials. Further experiments coupled with the mathematical model demonstrate
the control of the sign of Gaussian curvature, which is used in combination
with heat transfer effects to design LCEs that self-clean as a result of
temperature-dependent actuation properties
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