10,374 research outputs found

    Solubility of non-polar gases in electrolyte solutions

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    Solubility theory describes the effects of both concentration and temperature on solute activity coefficients. It predicts the salting-out effect and the decrease in solubility of non-polar gases with increased electrolyte concentration, and can be used to calculate heats of solution, entropies, and partial molal volumes of dissolved gase

    Weed Control for Reduced Tillage Systems

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    X ray imaging microscope for cancer research

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    The NASA technology employed during the Stanford MSFC LLNL Rocket X Ray Spectroheliograph flight established that doubly reflecting, normal incidence multilayer optics can be designed, fabricated, and used for high resolution x ray imaging of the Sun. Technology developed as part of the MSFC X Ray Microscope program, showed that high quality, high resolution multilayer x ray imaging microscopes are feasible. Using technology developed at Stanford University and at the DOE Lawrence Livermore National Laboratory (LLNL), Troy W. Barbee, Jr. has fabricated multilayer coatings with near theoretical reflectivities and perfect bandpass matching for a new rocket borne solar observatory, the Multi-Spectral Solar Telescope Array (MSSTA). Advanced Flow Polishing has provided multilayer mirror substrates with sub-angstrom (rms) smoothnesss for the astronomical x ray telescopes and x ray microscopes. The combination of these important technological advancements has paved the way for the development of a Water Window Imaging X Ray Microscope for cancer research

    Effect of Calcium Source, Dietary Calcium Concentration, and Gestation Phase on Various Bone Characteristics in Gestating Gilts

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    Sixty gravid crossbred gilts were allotted to a 2 x 3 x 2 factorial arrangement of treatments: two Ca sources (sun-cured alfalfa meal and CaC03), three dietary concentrations of Ca (50, 75, and 100% of NRC requirements), and two phases of gestation (55 and 105 d). The objectives were to determine the effect of Ca source, dietary Ca concentration, and gestation phase on bone characteristics (bone breaking strength, bone ash percentage, bone density, and bone ash density in the rib, thoracic, and coccygeal bones), to correlate bone responses to determine relative bone activity, and to determine reliability of the coccygeal bones as indicators of Ca status in the body. At 55 d, rib strength and coccygeal ash content were lower (P \u3c .01) than at 105 d of gestation. A gestation phase x Ca concentration (P \u3c .05) interaction occurred. As Ca concentration increased, thoracic strength and rib ash responded quadratically during each gestation phase, for which at 55 d a minima and at 105 d a maxima was produced at 75% of NRC. A Ca source x Ca concentration ( P \u3c .05) interaction occurred. Gilts fed alfalfa had the lowest rib bone and ash density when fed 75% of NRC for Ca, whereas gilts fed CaC03 were highest at this level of Ca compared with the other concentrations. Generally, all bones were positively correlated with respect to their response to dietary Ca concentration. Few negative correlations were observed. At this level of physiological maturity, there was no effect of Ca source and little effect of gestation phase on the bone variables measured at the dietary Ca concentrations used in this experiment. The rib and thoracic bones seem to be the most responsive to dietary Ca concentration

    Design analysis of levitation facility for space processing applications

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    Containerless processing facilities for the space laboratory and space shuttle are defined. Materials process examples representative of the most severe requirements for the facility in terms of electrical power, radio frequency equipment, and the use of an auxiliary electron beam heater were used to discuss matters having the greatest effect upon the space shuttle pallet payload interfaces and envelopes. Improved weight, volume, and efficiency estimates for the RF generating equipment were derived. Results are particularly significant because of the reduced requirements for heat rejection from electrical equipment, one of the principal envelope problems for shuttle pallet payloads. It is shown that although experiments on containerless melting of high temperature refractory materials make it desirable to consider the highest peak powers which can be made available on the pallet, total energy requirements are kept relatively low by the very fast processing times typical of containerless experiments and allows consideration of heat rejection capabilities lower than peak power demand if energy storage in system heat capacitances is considered. Batteries are considered to avoid a requirement for fuel cells capable of furnishing this brief peak power demand

    Low-Silica and High-Calcium Stone in the Newman Limestone (Mississippian) on Pine Mountain, Letcher County, Southeastern Kentucky

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    The coal industry of Kentucky is an important market for limestone. Coal producers use limestone as rock dust for explosion abatement in underground coal mines and as a neutralizing agent in surface-mine reclamation and acid-drainage control. Haulage-road construction and maintenance require crushed stone. Coal-bearing rocks of Pennsylvanian age in the Eastern Kentucky Coal Field generally do not contain limestones that are sufficiently thick to quarry or mine economically, but in the southeastern part of the coal field, fault movement has brought the Newman Limestone to the surface along Pine Mountain. The Newman was sampled at three sites in Letcher County to determine its chemical quality and potential for industrial use, particularly as a source of low-silica rock dust. Analysis of the foot-by-foot samples shows that the Newman contains several zones of low-silica stone, 10 to 39 feet thick. A few intervals of high-calcium limestone, 12 to 24 feet thick, coincide with or occur in the low-silica zones. The deposits of low-silica and high-calcium stone are thickest in the southwestern part of Letcher County and commonly thin northeastward. The thicker deposits of chemically pure limestone and dolomite may be an economically exploitable source of rock dust for underground coal mines, and a source of stone for surface-mine reclamation and acid-drainage control. Production from deposits in the Newman, however, will be complicated by the steep southeastward to southward dip (20 to 42°) of the beds, possible displacement along small faults, and fracturing of the limestone

    The Effect of Lime on Nitrification in the Grundy Silt Loam

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    To secure information preliminary to the laying out of field experiments for a study of the value of liming and growing inoculated legumes on the Grundy silt loam, an important soil type in Southern Iowa, tests have been conducted on this soil during the past winter in the greenhouse and laboratory. These tests were planned to study the effect of various amounts of limestone and to determine the influence of lime alone and in combination with certain fertilizers on crop yields and on the biological and chemical conditions in the soil

    Ferromagnetic resonance in periodic particle arrays

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    We report measurements of the ferromagnetic resonance (FMR) spectra of arrays of submicron size periodic particle arrays of permalloy produced by electron-beam lithography. In contrast to plane ferromagnetic films, the spectra of the arrays show a number of additional resonance peaks, whose position depends strongly on the orientation of the external magnetic field and the interparticle interaction. Time-dependent micromagnetic simulation of the ac response show that these peaks are associated with coupled exchange and dipolar spin wave modesComment: 4 pages, 4 figure

    General existence proof for rest frame systems in asymptotically flat space-time

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    We report a new result on the nice section construction used in the definition of rest frame systems in general relativity. This construction is needed in the study of non trivial gravitational radiating systems. We prove existence, regularity and non-self-crossing property of solutions of the nice section equation for general asymptotically flat space times. This proves a conjecture enunciated in a previous work.Comment: 14 pages, no figures, LaTeX 2

    Outcome and mortality of hospital admission with COVID-19 for individuals with parkinsonian syndromes

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    ObjectiveTo evaluate features of Parkinson’s disease (PD) and atypical Parkinson’s syndromes (APS) associated with poor outcome and mortality in people with COVID-19 in a hospital setting.BackgroundPrevious studies have demonstrated increased mortality of COVID-19 in people with PD. However, it is not known whether this is associated with disease-related factors (eg autonomic dysfunc- tion, dysphagia).MethodsAn online survey tool captured anonymised patient data from hospital admission records of people with PD and APS who tested positive for COVID-19 between February 2020 and July 2021. We will use Cox proportional hazards and linear regression models to evaluate which characteristics are associ- ated with mortality, increased care requirement and more severe COVID-19 infection. Models will be adjusted for known associations with poor outcome, such as co-morbidities, age and sex.ResultsData were collected from 556 admissions from 21 UK sites: 66.2% male; median (IQR) age 80 (11) years; median disease duration 5 (7) years. 19.2% were asymptomatic, 28.8% had mild symptoms and 52.5% required respiratory support. 38.3% died within 4 weeks of a positive COVID-19 test. Preliminary Kaplan-Meier curves suggest that co-existing dementia, marked motor fluctuations and more advanced Hoehn and Yahr stage may be associated with 28-day mortality. Full statistical analysis is in progress.ConclusionsIdentification of Parkinson’s features associated with poor in-hospital COVID-19 outcome will allow a more informed discussion relating to individual COVID-19 risk.</jats:sec
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