868 research outputs found

    First-principle density-functional calculation of the Raman spectra of BEDT-TTF

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    We present a first-principles density-functional calculation for the Raman spectra of a neutral BEDT-TTF molecule. Our results are in excellent agreement with experimental results. We show that a planar structure is not a stable state of a neutral BEDT-TTF molecule. We consider three possible conformations and discuss their relation to disorder in these systems.Comment: 3 pages, 2 figures, submitted to the proceedings of ISCOM 200

    National agricultural cooperative federation

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    노트 : The KASS team projects a two- to three-fold increase in product marketings and an approximate three-fold increase in total volume of input supplies required by 1985. NACF should not attempt to expand proportional to the need for input and product market services over the next 1 1/2 decades. Rather the target should be to retain its present non-government intrusted product market share (about 11%) and to move from 80% of the modern input supply market to less than half in 1985. Private sector competition should be encouraged. Projections in Chapter IV indicate that NACF Primary cooperatives in the aggregate are capable of almost doubling their product marketing and input supply volume with existing resources and personnel. The NACF is currently seeking funds to increase its role in programming and financing major capital investments in agricultural production and marketing. This represents essentially a new role for the organization. This kind of activity should basically be left to the private sector and the AFDC. In any case, NACF should not undertake such activity without a very clear assessment of the organization's capacity to implement the program and at the same time improve its capacity to provide credit, farm supply, and marketing services to agriculture

    The UT 19-channel DC SQUID based neuromagnetometer

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    A l9-channel DC SQUID based neuromagnetometer is under construction at the University of Twente (UT). Except for the cryostat all elements of the system are developed at the UT. It comprises 19 wire-wound first-order gradiometers in a hexagonal configuration. The gradiometers are connected to planar DC SQUIDS fabricated with a Nb/Al, AlOx/Nb technology. For this connection we developed a method to bond a Nb wire to a Nb thin-film. The SQUIDs are placed in compartmentalised Nb modules. Further, external feedback is incorporated in order to eliminate cross talk between the gradiometers. The electronics basically consist of a phase-locked loop operating with a modulation frequency of 100 kHz. Between SQUID and preamplifier a small transformer is used to limit the noise contribution of the preamplifier. In the paper the overall system is described, and special attention is paid to the SQUID module (bonding, compartments, external-feedback setup, output transformer)

    Mechanics of cooling liquids by forced evaporation in bubbles

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    Injecting a non-dissolvable gas into a saturated liquid results in sub-cooling of the liquid due to forced evaporation into the bubble. Previous studies assumed the rate of evaporation of liquid into the bubble to be independent of the degree of sub-cooling. In our study we quantify the bubble growth by direct observation using high speed imaging and prove that this hypothesis is not true. A phenomenological model of the bubble growth as a function of the degree of sub-cooling is developed and we find excellent agreement between the measurements and theory. This bubble cooling process is employed in cooling a liquid. By identification of all heat flows, we can well describe the cool down curve using bubble cooling. Bubble cooling provides an alternative cooling method for liquids without the use of complicated cooling techniques

    Міфологізм у символістській прозі Клима Поліщука

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    The particularities of mythology in symbolist prose by Klym Polishchuk are explained in the article. There are two time planes of plot evolvement in fantastic stories by Klym PolishchukG past and present. Fantastic events in the past have continuation in

    Development of a novel method for the exploration of the thermal response of superfluid helium cooled superconducting cables to pulse heat loads

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    Management of transient heat deposition in superconducting magnets and its extraction from the aforementioned is becoming increasingly important to bring high energy particle accelerator performance to higher beam energies and intensities. Precise knowledge of transient heat deposition phenomena in the magnet cables will permit to push the operation of these magnets as close as possible to their current sharing limit, without unduly provoking magnet quenches. With the prospect of operating the Large Hadron Collider at CERN at higher beam energies and intensities an investigation into the response to transient heat loads of LHC magnets, operating in pressurized superfluid helium, is being performed. The more frequently used approach mimics the cable geometry by resistive wires and uses Joule-heating to deposit energy. Instead, to approximate as closely as possible the real magnet conditions, a novel method for depositing heat in cable stacks made out of superconducting magnet-cables has been developed. The goal is to measure the temperature difference as a function of time between the cable stack and the superfluid helium bath depending on heat load and heat pulse length. The heat generation in the superconducting cable and precise measurement of small temperature differences are major challenges. The functional principle and experimental set-up are presented together with proof of principle measurements

    Baseline design of a sorption-based Joule-Thomson cooler chain for the METIS instrument in the E-ELT

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    METIS, the Mid-Infrared E-ELT Imager and Spectrograph, is one of the proposed instruments in E-ELT (European Extremely Large Telescope). Its infrared detectors require multiple operating temperatures below 77 K. Therefore, active coolers have to be deployed to provide sub-liquid-nitrogen (sub-LN2) temperature cooling. However, the sensitive imaging optical detecting system also demands very low levels of vibration. Thus, the University of Twente proposed a vibration-free cooling technique based on physical sorption. In this paper, we describe the baseline design of such a sorption-based Joule-Thomson cooler chain for the METIS instrument, that is able to deliver cooling powers of 0.4 W at 8 K, 1.1 W at 25 K and 1.4 W at 40 K from a 70-K heat sinking. This design is based on working fluid selection, cascading cooler stages and operating parameter optimization. Also, the performance of the resulting cooler design is analyzed

    SupernetNL program: 3.4 km 110 kV AC underground superconducting cable in the Dutch grid

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    TenneT, a leading European electricity transmission system operator (TSO) is planning to install a 3.4 km long underground superconducting 110 kV cable as part of the Dutch electricity grid, in the city of Enschede. HTS cables have already been demonstrated on a relatively small scale in other countries, but they are usually not part of the meshed high-voltage grid and the length of the relevant cable section generally does not exceed 1 km. In 2009, a 600-meter section of HTS cable was installed in New York, and in 2014 a 1-km long section was taken in operation in Essen, Germany to replace a 10 kV AC medium-voltage line. In the Supernet NL program, TenneT is working together with several leading knowledge institutes including University of Twente, Delft University of Technology, the Institute of Science and Sustain- able Development (IWO), HAN University of Applied Sciences and RH Marine. These institutes have been investigating control engineering aspects and the requirements the cable must meet. In the meantime, the tender process has been started which consists of two phases. In the fi rst phase (summer 2017) appropriate candidates are selected directly followed by a call for tender in August. Receipt of the best and fi nal offer is scheduled for the end of November. In the presentation, the project will be introduced and requirements will be discussed, specifi cally focusing on the cryogenic aspects

    Effects of Feeding Brassica Mixture Cover Crops During Backgrounding on Carcass Traits and Fresh Meat Quality

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    Objective: Determine effects of feeding brassica-based cover crops to cattle during backgrounding on carcass characteristics and tenderness, flavor, and juiciness of longissimus dorsi steaks
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