34,895 research outputs found

    Magnetic reconnection in plasma under inertial confinement fusion conditions driven by heat flux effects in Ohm's law

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    In the interaction of high-power laser beams with solid density plasma there are a number of mechanisms that generate strong magnetic fields. Such fields subsequently inhibit or redirect electron flows, but can themselves be advected by heat fluxes, resulting in complex interplay between thermal transport and magnetic fields.We show that for heating by multiple laser spots reconnection of magnetic field lines can occur, mediated by these heat fluxes, using a fully implicit 2D Vlasov-Fokker-Planck code. Under such conditions, the reconnection rate is dictated by heat flows rather than Alfv\`enic flows. We find that this mechanism is only relevant in a high Ī²\beta plasma. However, the Hall parameter Ļ‰cĻ„ei\omega_c \tau_{ei} can be large so that thermal transport is strongly modified by these magnetic fields, which can impact longer time scale temperature homogeneity and ion dynamics in the system

    Nu sub 1 plus nu sub 3 combination band of SO2

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    The infrared-active vibration-rotation combination band nu sub 1 + nu sub 3 of sulfur dioxide was measured with moderately high spectral resolution. Quantum number identifications of spectral lines were made by comparison with theoretically computed spectra which include the effects of centrifugal distortion. Relative line intensities were also calculated. The band center for nu sub 1 + nu sub 3 was determined to be 2499.60 + or - 0.10/cm

    Fundamental bands of S(32)O2(16)

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    The infrared-active vibration-rotation fundamentals of sulfur dioxide were measured with moderately high spectral resolution. Quantum number assignments were made for spectral lines from J = O to 57, by comparison with theoretically computed spectra which include the effects of centrifugal distortion. The following values for the band centers were determined: nu sub 1 = 1151.65 + or - 0.10/cm, nu sub 2 = 517.75 + or - 0.10/cm, and nu sub 3 = 1362.00 + or - 0.10/cm. Intensities of the observed lines have also been computed. Dipole moment derivatives were obtained

    On-board timeline validation and repair : a feasibility study

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    We report on the progress and outcome of a recent ESAfunded project (MMOPS) designed to explore the feasibility of on-board reasoning about payload timelines. The project sought to examine the role of on-board timeline reasoning and the operational context into which it would fit. We framed a specification for an on-board service that fits with existing practices and represents a plausible advance within sensible constraints on the progress of operations planning. We have implemented a prototype to demonstrate the feasibility of such a system and have used it to show how science gathering operations might be improved by its deployment

    Magnetodielectric coupling in Mn3O4

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    We have investigated the dielectric anomalies associated with spin ordering transitions in the tetragonal spinel Mn3_3O4_4, using thermodynamic, magnetic, and dielectric measurements. We find that two of the three magnetic ordering transitions in Mn3_3O4_4 lead to decreases in the temperature dependent dielectric constant at zero applied field. Applying a magnetic field to the polycrystalline sample leaves these two dielectric anomalies practically unchanged, but leads to an increase in the dielectric constant at the intermediate spin-ordering transition. We discuss possible origins for this magnetodielectric behavior in terms of spin-phonon coupling. Band structure calculations suggest that in its ferrimagnetic state, Mn3_3O4_4 corresponds to a semiconductor with no orbital degeneracy due to strong Jahn-Teller distortion.Comment: 6 pages, 7 figure

    Sintering of screen-printed platinum thick films for electrode applications

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    Pt electrodes with a 6-8-Ī¼m thickness were produced on alumina substrates by a double-print Pt screen-printing process that included a sequential heat treatment at 600 Ā°C and 1300 Ā°C. This process improved the final sintered double-print film because the first printed layer acted as a sintering template for the second printed layer. The sintered Pt films have a 95% coverage of the alumina surface, 92% density, 0.73-Ī¼m average surface roughness, and 16.10āˆ’5 Ī© cm resistivity. The sintering behavior of Pt films exhibited three stages of densification: Stage I (T Ā°C < 700 Ā°C), exhibiting neck growth, and Stage II (700 < T Ā°C < 1300 Ā°C), exhibiting grain growth, have activation energies of 64 kJ/mol and 125 kJ/mol, respectively. Stage III exhibits a decrease in shrinkage due to Pt coalescence and island formation. The transition temperature, 700 Ā°C, between Stages I and II corresponds to an anomalous increase in surface roughness and resistivity. The thickness of Pt films was a critical parameter for achieving alumina surface coverage. Uniaxial pressing of dried Pt films increased densification and reduced the surface roughness of double-print Pt film

    Potentialities of proteinoids for nutritional investigation

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    Simultaneous synthesis of amino acids and proteinoid production for nutritional investigatio

    Does Taping of the Annular Pulleys of the Fingers Improve Grip Strength in Climbers?

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    Indoor sport climbing will debut as a new Olympic discipline at the 2020 summer games in Tokyo. The annular pulleys of the fingers are the most commonly reported injured structure in climbing. There are five annular pulleys within each finger and referred to as the A1, A2, A3, A4 and A5. The A2 and A4 structurally maintain the integrity of the flexor tendon system due to their direct attachment to the underlying bone. The A2 is the largest pulley and capable of withstanding up to 400 newton of force. Anecdotal evidence suggests some climbers apply athletic tape to the fingers both as a prophylactic measure to prevent annular pulley injury and to increase their grip strength capability. Grip refers to the method by which the climber holds the climbing surface to facilitate movement. The type of grip the climber uses largely depends on the size and shape of the available hand-holds, the climberā€™s body orientation in relation to the climbing surface and the strength of the climber. A common type of grip used in climbing is the closed crimp position. In this position the proximal interphalangeal joint is flexed at approximately 100Ā° and the distal interphalangeal joint is hyperextended at approximately 210Ā°. The distal palmer surface of the index, middle and ring fingers are normally in contact with the surface and the thumb often placed over the dorsal surface of the index finger to generate more force. The aim of the study was to investigate if taping the fingers increased crimp grip strength in uninjured climbers. Following ethical approval by the Leeds Beckett University research ethics committee, 50 active climbers (25 male, 25 female) were recruited. Using a within subject repeated measures design, a Jamar plus digital dynamometer was used to measure crimp grip strength (3 trial mean, dominant and non-dominant hand, tape and no-tape). The order of conditions was randomised and each participant performed each grip. The tape condition involved applying a 10cm piece of 1ā€ Lewis-Plast zinc oxide tape to the proximal interphalangeal joint of the index, middle and ring fingers using the H-tape method. There was no statistically significant difference (p = 0.922, paired t-test) in crimp grip strength between tape (24.03 Ā± 6.9kg) and no tape (23.99 Ā± 7.2kg) conditions. Taping the annular pulleys did not increase crimp grip strength as measured using hand held dynamometry in uninjured climbers
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