652 research outputs found

    Low power, compact charge coupled device signal processing system

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    A variety of charged coupled devices (CCDs) for performing programmable correlation for preprocessing environmental sensor data preparatory to its transmission to the ground were developed. A total of two separate ICs were developed and a third was evaluated. The first IC was a CCD chirp z transform IC capable of performing a 32 point DFT at frequencies to 1 MHz. All on chip circuitry operated as designed with the exception of the limited dynamic range caused by a fixed pattern noise due to interactions between the digital and analog circuits. The second IC developed was a 64 stage CCD analog/analog correlator for performing time domain correlation. Multiplier errors were found to be less than 1 percent at designed signal levels and less than 0.3 percent at the measured smaller levels. A prototype IC for performing time domain correlation was also evaluated

    Subsonic Flight Tests of a 1/7-Scale Radio-Controlled Model of the North American X-15 Airplane with Particular Reference to High Angel-of-Attack Conditions

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    An investigation of the subsonic stability and control characteristics of an unpowered 1/7-scale model based on the North American X-15 airplane was conducted by using a radio-controlled model launched from a helicopter and flown in free-gliding flight. At angles of attack below about 20 deg. where the model motions represent those of the X-15 airplane, the model was found to be both longitudinally and laterally stable, and the all-movable tail surfaces were found to be very effective. The model could also be flown at much higher angles of attack where the model motions did not necessarily represent those of the airplane because of slight geometrical differences and Reynolds number effects, but these test results are useful in evaluating the effectiveness at these angles of the type of lateral control system used in the X-15 airplane. In some cases, the model was flown to angles of attack as high as 60 or 70 deg. without encountering divergent or uncontrollable conditions. For some flights in which the model was subjected to rapid maneuvers, spinning motions were generated by application of corrective controls to oppose the direction of rotation. Rapid recoveries from this type of motion were achieved by applying roll control in the direction of rotation

    Experiment Simulation Configurations Used in DUNE CDR

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    The LBNF/DUNE CDR describes the proposed physics program and experimental design at the conceptual design phase. Volume 2, entitled The Physics Program for DUNE at LBNF, outlines the scientific objectives and describes the physics studies that the DUNE collaboration will perform to address these objectives. The long-baseline physics sensitivity calculations presented in the DUNE CDR rely upon simulation of the neutrino beam line, simulation of neutrino interactions in the far detector, and a parameterized analysis of detector performance and systematic uncertainty. The purpose of this posting is to provide the results of these simulations to the community to facilitate phenomenological studies of long-baseline oscillation at LBNF/DUNE. Additionally, this posting includes GDML of the DUNE single-phase far detector for use in simulations. DUNE welcomes those interested in performing this work as members of the collaboration, but also recognizes the benefit of making these configurations readily available to the wider community.Comment: 9 pages, 4 figures, configurations in ancillary file

    Nucleon Decay, Atmospheric Neutrinos, and Cosmic Rays at DUNE: September 2016 Progress Report

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    We report on the progress made within the Nucleon Decay, Atmospheric Neutrinos, and Cosmogenics Physics Working Groups since the DUNE CDR, and in particular in the period September 2015 { September 2016. This note is also intended to provide input for the September 2016 Preliminary Report of the Far Detector Task Force. We report jointly for the three WGs since they are tightly coupled. They make use of the same DUNE Far Detector for their physics studies, they share the same energy regime, and they are all characterized by random, non-beam triggers. Finally, cosmogenic events are a background for atmospheric neutrino physics, and both cosmogenic events and atmospheric neutrinos are a background for nucleon decay physics. Recent progress within the Nucleon Decay, Atmospheric Neutrinos and Cosmogenics Physics Working Groups is reported in Secs. II, III and IV, respectively

    Arterial oxygen content is precisely maintained by graded erythrocytotic responses in settings of high/normal serum iron levels, and predicts exercise capacity: an observational study of hypoxaemic patients with pulmonary arteriovenous malformations.

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    Oxygen, haemoglobin and cardiac output are integrated components of oxygen transport: each gram of haemoglobin transports 1.34 mls of oxygen in the blood. Low arterial partial pressure of oxygen (PaO2), and haemoglobin saturation (SaO2), are the indices used in clinical assessments, and usually result from low inspired oxygen concentrations, or alveolar/airways disease. Our objective was to examine low blood oxygen/haemoglobin relationships in chronically compensated states without concurrent hypoxic pulmonary vasoreactivity.165 consecutive unselected patients with pulmonary arteriovenous malformations were studied, in 98 cases, pre/post embolisation treatment. 159 (96%) had hereditary haemorrhagic telangiectasia. Arterial oxygen content was calculated by SaO2 x haemoglobin x 1.34/100.There was wide variation in SaO2 on air (78.5-99, median 95)% but due to secondary erythrocytosis and resultant polycythaemia, SaO2 explained only 0.1% of the variance in arterial oxygen content per unit blood volume. Secondary erythrocytosis was achievable with low iron stores, but only if serum iron was high-normal: Low serum iron levels were associated with reduced haemoglobin per erythrocyte, and overall arterial oxygen content was lower in iron deficient patients (median 16.0 [IQR 14.9, 17.4]mls/dL compared to 18.8 [IQR 17.4, 20.1]mls/dL, p<0.0001). Exercise tolerance appeared unrelated to SaO2 but was significantly worse in patients with lower oxygen content (p<0.0001). A pre-defined athletic group had higher Hb:SaO2 and serum iron:ferritin ratios than non-athletes with normal exercise capacity. PAVM embolisation increased SaO2, but arterial oxygen content was precisely restored by a subsequent fall in haemoglobin: 86 (87.8%) patients reported no change in exercise tolerance at post-embolisation follow-up.Haemoglobin and oxygen measurements in isolation do not indicate the more physiologically relevant oxygen content per unit blood volume. This can be maintained for SaO2 ≥78.5%, and resets to the same arterial oxygen content after correction of hypoxaemia. Serum iron concentrations, not ferritin, seem to predict more successful polycythaemic responses

    Determination of muon momentum in the MicroBooNE LArTPC using an improved model of multiple Coulomb scattering

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    We discuss a technique for measuring a charged particle's momentum by means of multiple Coulomb scattering (MCS) in the MicroBooNE liquid argon time projection chamber (LArTPC). This method does not require the full particle ionization track to be contained inside of the detector volume as other track momentum reconstruction methods do (range-based momentum reconstruction and calorimetric momentum reconstruction). We motivate use of this technique, describe a tuning of the underlying phenomenological formula, quantify its performance on fully contained beam-neutrino-induced muon tracks both in simulation and in data, and quantify its performance on exiting muon tracks in simulation. Using simulation, we have shown that the standard Highland formula should be re-tuned specifically for scattering in liquid argon, which significantly improves the bias and resolution of the momentum measurement. With the tuned formula, we find agreement between data and simulation for contained tracks, with a small bias in the momentum reconstruction and with resolutions that vary as a function of track length, improving from about 10% for the shortest (one meter long) tracks to 5% for longer (several meter) tracks. For simulated exiting muons with at least one meter of track contained, we find a similarly small bias, and a resolution which is less than 15% for muons with momentum below 2 GeV/c. Above 2 GeV/c, results are given as a first estimate of the MCS momentum measurement capabilities of MicroBooNE for high momentum exiting tracks
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