322 research outputs found

    Tradeoffs in jet inlet design: a historical perspective

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    The design of the inlet(s) is one of the most demanding tasks of the development process of any gas turbine-powered aircraft. This is mainly due to the multi-objective and multidisciplinary nature of the exercise. The solution is generally a compromise between a number of conflicting goals and these conflicts are the subject of the present paper. We look into how these design tradeoffs have been reflected in the actual inlet designs over the years and how the emphasis has shifted from one driver to another. We also review some of the relevant developments of the jet age in aerodynamics and design and manufacturing technology and we examine how they have influenced and informed inlet design decision

    In-situ characterization of the Hamamatsu R5912-HQE photomultiplier tubes used in the DEAP-3600 experiment

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    The Hamamatsu R5912-HQE photomultiplier-tube (PMT) is a novel high-quantum efficiency PMT. It is currently used in the DEAP-3600 dark matter detector and is of significant interest for future dark matter and neutrino experiments where high signal yields are needed. We report on the methods developed for in-situ characterization and monitoring of DEAP's 255 R5912-HQE PMTs. This includes a detailed discussion of typical measured single-photoelectron charge distributions, correlated noise (afterpulsing), dark noise, double, and late pulsing characteristics. The characterization is performed during the detector commissioning phase using laser light injected through a light diffusing sphere and during normal detector operation using LED light injected through optical fibres

    Measurement of the scintillation time spectra and pulse-shape discrimination of low-energy beta and nuclear recoils in liquid argon with DEAP-1

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    The DEAP-1 low-background liquid argon detector was used to measure scintillation pulse shapes of electron and nuclear recoil events and to demonstrate the feasibility of pulse-shape discrimination (PSD) down to an electron-equivalent energy of 20 keV. In the surface dataset using a triple-coincidence tag we found the fraction of beta events that are misidentified as nuclear recoils to be <1.4×107<1.4\times 10^{-7} (90% C.L.) for energies between 43-86 keVee and for a nuclear recoil acceptance of at least 90%, with 4% systematic uncertainty on the absolute energy scale. The discrimination measurement on surface was limited by nuclear recoils induced by cosmic-ray generated neutrons. This was improved by moving the detector to the SNOLAB underground laboratory, where the reduced background rate allowed the same measurement with only a double-coincidence tag. The combined data set contains 1.23×1081.23\times10^8 events. One of those, in the underground data set, is in the nuclear-recoil region of interest. Taking into account the expected background of 0.48 events coming from random pileup, the resulting upper limit on the electronic recoil contamination is <2.7×108<2.7\times10^{-8} (90% C.L.) between 44-89 keVee and for a nuclear recoil acceptance of at least 90%, with 6% systematic uncertainty on the absolute energy scale. We developed a general mathematical framework to describe PSD parameter distributions and used it to build an analytical model of the distributions observed in DEAP-1. Using this model, we project a misidentification fraction of approx. 101010^{-10} for an electron-equivalent energy threshold of 15 keV for a detector with 8 PE/keVee light yield. This reduction enables a search for spin-independent scattering of WIMPs from 1000 kg of liquid argon with a WIMP-nucleon cross-section sensitivity of 104610^{-46} cm2^2, assuming negligible contribution from nuclear recoil backgrounds.Comment: Accepted for publication in Astroparticle Physic

    Search for dark matter with a 231-day exposure of liquid argon using DEAP-3600 at SNOLAB

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    DEAP-3600 is a single-phase liquid argon (LAr) direct-detection dark matter experiment, operating 2 km underground at SNOLAB (Sudbury, Canada). The detector consists of 3279 kg of LAr contained in a spherical acrylic vessel. This paper reports on the analysis of a 758  tonne⋅day exposure taken over a period of 231 live-days during the first year of operation. No candidate signal events are observed in the WIMP-search region of interest, which results in the leading limit on the WIMP-nucleon spin-independent cross section on a LAr target of 3.9×10−45  cm2 (1.5×10−44  cm2) for a 100  GeV/c2 (1  TeV/c2) WIMP mass at 90% C.L. In addition to a detailed background model, this analysis demonstrates the best pulse-shape discrimination in LAr at threshold, employs a Bayesian photoelectron-counting technique to improve the energy resolution and discrimination efficiency, and utilizes two position reconstruction algorithms based on the charge and photon detection time distributions observed in each photomultiplier tube

    Electromagnetic backgrounds and potassium-42 activity in the DEAP-3600 dark matter detector

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    Design and construction of the DEAP-3600 dark matter detector

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    The Dark matter Experiment using Argon Pulse-shape discrimination (DEAP) has been designed for a direct detection search for particle dark matter using a single-phase liquid argon target. The projected cross section sensitivity for DEAP-3600 to the spin-independent scattering of Weakly Interacting Massive Particles (WIMPs) on nucleons is 10−46cm2 for a 100 GeV/c2 WIMP mass with a fiducial exposure of 3 tonne-years. This paper describes the physical properties and construction of the DEAP-3600 detector

    RTOG/NRG 1115 Quality of Life of Phase III Dose Escalated Radiation Therapy (RT) and Standard Androgen Deprivation Therapy (ADT) with GnRH Agonist vs. Dose Escalated RT and ADT with GnRH Agonist and Orteronel (TAK-700) for Men with High-Risk Prostate

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    Purpose/Objective(s): Quality of life (QOL) was assessed with the hypothesis that QOL and fatigue scores would not differ significantly between the ADT + RT (Arm A) and the experimental group receiving ADT + RT + oreteronel (Arm B). Materials/Methods: In both arms, ADT with GnRH agonist was given for 24 mos, and dose escalated RT started 8-10 wks after initiation of ADT. In Arm B, oreteronel was given BID for 24 mos. QOL was measured with Expanded Prostate Cancer Index Composite (EPIC) and EQ-5D global QOL assessment. EPIC has 4 domains: bowel, urinary, sexual, and hormonal. EQ-5D index score was calculated using health states obtained from 5 dimensions, and a visual analog score (VAS). For EPIC, EQ-5D index and VAS, higher scores indicate better QOL. Fatigue was measured by the 7-item Patient-Reported Outcome Measurement Information System (PROMIS) short form. Total score is standardized into a T-score with mean of 50 and standard deviation of 10 with higher score representing more fatigue. Change scores, calculated as follow-up minus baseline, were compared between arms. Longitudinal analysis using repeated measures mixed effects models was conducted (prior to ADT [baseline], one wk prior to starting RT, last wk of RT, and 1 and 2.5 yrs after initiation of therapy). Results: Of 231 eligible patients, 196 consented to QOL, 102 on Arm A and 94 on Arm B. Compliance prior to start of RT and end of RT was 83%. At 1 and 2.5 yrs, 80% and 62% of pts, respectively, completed the EPIC. There were no differences between any EPIC domain between arms from the start of RT through the end of follow-up. Men on oreteronel had a significantly greater decline in bowel score prior to starting RT then control patients (-6.12, 95% confidence interval [CI]: -9.24, -3.01 vs. -1.93, 95% CI: -4.48, 0.63, respectively, p=0.038). Arm B patients also had a statistically significant and clinically meaningful worse change in urinary score vs control from baseline to pre-RT (-2.33, 95% CI: -5.02, 0.36 vs. 1.38, 95% CI: -1.07, 3.83, respectively, p=0.043). No other timepoints were significant. The only sig. between arm difference in EPIC sexual and hormonal scores was also at pre-RT in favor of Arm A over Arm B; p=0.024 and p=0.0024 respectively). Fatigue was also greater in the oreteronel patients prior to starting RT (3.81, 95% CI: 1.88, 5.74 vs. 1.18, 95% CI: -0.23, 2.60, p=0.028). Conclusion: The addition of oreteronel to RT and ADT resulted in greater declines in QOL prior to the start of RT but did not result in significant differences at any other time points. Although oreteronel development has been halted, the QOL results are encouraging for other drugs in this class that remain under investigation. In ongoing prospective trials, QOL impacts should be measured in conjunction with changes in clinical outcome and survival. This project was supported by grants UG1CA189867, U10CA180868, U10CA180822 from the National Cancer Institute and Takeda Pharmaceutical

    Predictors of multidomain decline in health‐related quality of life after stereotactic body radiation therapy (SBRT) for prostate cancer

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/136687/1/cncr30519_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136687/2/cncr30519.pd
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