3,030 research outputs found

    Volumetric measurement of tank volume

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    A method is disclosed for determining the volume of compressible gas in a system including incompressible substances in a zero-gravity environment consisting of measuring the change in pressure (delta P) for a known volume change rate (delta V/delta t) in the polytrophic region between isothermal and adiabatic conditions. The measurements are utilized in an idealized formula for determining the change in isothermal pressure (delta P sub iso) for the gas. From the isothermal pressure change (delta iso) the gas volume is obtained. The method is also applicable to determination of gas volume by utilizing work (W) in the compression process. In a passive system, the relationship of specific densities can be obtained

    An Inquiry Into the Relationship Between Sulfur and Plant Growth

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    This 64 page thesis attempts to clarify the relationship between sulfur and plant growth

    Ultrasonic Beam Propagation in Turbulent Flow

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    A study was conducted to examine how a coherent sound burst, such as those used in an ultrasonic flowmeter, crosses a turbulent flow field. Many ultrasonic flowmeters use a time of flight method to determine the mean flow. This measurement method sends sound waves at some angle across a velocity field between two transducers, and the time required for the sound burst to cross this distance is measured on the order of nanoseconds. The system then reverses so that the sound wave burst is sent in the opposite direction. Knowing the distance traveled, the local average sound speed, and the back and forth travel times, the integrated velocity along the sound path can be computed. By using average values for distance and time, an average flowrate may be determined. To perform this analysis, data from several velocity fields were used to determine how a coherent sound burst would travel across the field. Comparisons of the infinitely thin case and the finite thickness case are performed. The study focused on using a modified ray trace method on a velocity field data set obtained using PIV

    Colorado Native Plant Society Newsletter, Vol. 9 No. 1, January-February 1984

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    The Colorado Native Plant Society Newsletter will be published on a bimonthly basis. The contents will consist primarily of a calendar of events, notes of interest, editorials, listings of new members and conservation news. Until there is a Society journal, the Newsletter will include short articles also. The deadline for the Newsletter is one month prior to its release.https://epublications.regis.edu/aquilegia/1023/thumbnail.jp

    Quadrupole moments of rotating neutron stars

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    Numerical models of rotating neutron stars are constructed for four equations of state using the computer code RNS written by Stergioulas. For five selected values of the star's gravitational mass (in the interval between 1.0 and 1.8 solar masses) and for each equation of state, the star's angular momentum is varied from J=0 to the Keplerian limit J=J_{max}. For each neutron-star configuration we compute Q, the quadrupole moment of the mass distribution. We show that for given values of M and J, |Q| increases with the stiffness of the equation of state. For fixed mass and equation of state, the dependence on J is well reproduced with a simple quadratic fit, Q \simeq - aJ^2/M c^2, where c is the speed of light, and a is a parameter of order unity depending on the mass and the equation of state.Comment: ReVTeX, 7 pages, 5 figures, additional material, and references adde

    Aquilegia, Vol. 34 No. 5, Winter 2010, Newsletter of the Colorado Native Plant Society

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    https://epublications.regis.edu/aquilegia/1135/thumbnail.jp

    Mechanical disruption of the blood-brain barrier following experimental concussion

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    Although concussion is now recognized as a major health issue, its non-lethal nature has limited characterization of the underlying pathophysiology. In particular, potential neuropathological changes have typically been inferred from non-invasive techniques or post-mortem examinations of severe traumatic brain injury (TBI). Here, we used a swine model of head rotational acceleration based on human concussion to examine blood–brain barrier (BBB) integrity after injury in association with diffuse axonal injury and glial responses. We then determined the potential clinical relevance of the swine concussion findings through comparisons with pathological changes in human severe TBI, where post-mortem examinations are possible. At 6–72 h post-injury in swine, we observed multifocal disruption of the BBB, demonstrated by extravasation of serum proteins, fibrinogen and immunoglobulin-G, in the absence of hemorrhage or other focal pathology. BBB disruption was observed in a stereotyped distribution consistent with biomechanical insult. Specifically, extravasated serum proteins were frequently observed at interfaces between regions of tissue with differing material properties, including the gray–white boundary, periventricular and subpial regions. In addition, there was substantial overlap of BBB disruption with regions of axonal pathology in the white matter. Acute perivascular cellular uptake of blood-borne proteins was observed to be prominent in astrocytes (GFAP-positive) and neurons (MAP-2-positive), but not microglia (IBA1-positive). Parallel examination of human severe TBI revealed similar patterns of serum extravasation and glial uptake of serum proteins, but to a much greater extent than in the swine model, attributed to the higher injury severity. These data suggest that BBB disruption represents a new and important pathological feature of concussion

    Quality assurance of radiotherapy in the ongoing EORTC 22042–26042 trial for atypical and malignant meningioma: Results from the dummy runs and prospective individual case Reviews

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    BACKGROUND: The ongoing EORTC 22042–26042 trial evaluates the efficacy of high-dose radiotherapy (RT) in atypical/malignant meningioma. The results of the Dummy Run (DR) and prospective Individual Case Review (ICR) were analyzed in this Quality Assurance (QA) study. MATERIAL/METHODS: Institutions were requested to submit a protocol compliant treatment plan for the DR and ICR, respectively. DR-plans (n=12) and ICR-plans (n=50) were uploaded to the Image-Guided Therapy QA Center of Advanced Technology Consortium server (http://atc.wustl.edu/) and were assessed prospectively. RESULTS: Major deviations were observed in 25% (n=3) of DR-plans while no minor deviations were observed. Major and minor deviations were observed in 22% (n=11) and 10% (n=5) of the ICR-plans, respectively. Eighteen% of ICRs could not be analyzed prospectively, as a result of corrupted or late data submission. CTV to PTV margins were respected in all cases. Deviations were negatively associated with the number of submitted cases per institution (p=0.0013), with a cutoff of 5 patients per institutions. No association (p=0.12) was observed between DR and ICR results, suggesting that DR’s results did not predict for an improved QA process in accrued brain tumor patients. CONCLUSIONS: A substantial number of protocol deviations were observed in this prospective QA study. The number of cases accrued per institution was a significant determinant for protocol deviation. These data suggest that successful DR is not a guarantee for protocol compliance for accrued patients. Prospective ICRs should be performed to prevent protocol deviations
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