4,767 research outputs found

    Effects of the disk tillage on soil condition, crop yield and weed infestation

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    This research was instigated by the fact that during the last decade annually repeated shallow disk tillage on the same field became frequent practice in Hungary. In order to study the changes of soil condition associated with disk tillage and to assess it is consequences, long-term tillage field experiments with different levels of nutrients were set up in 1991 (A) and in 1994 (B) on Chromic Luvisol at Gödöllö. The effects of disk tillage (D) and disk tillage combined with loosening (LD) on soil condition, on yield of maize and winter wheat, and on weed infestation were examined. The evaluation of soil condition measured by cone index and bulk density indicated that use of disking annually resulted in a dense soil layer below the disking depth (diskpan-compaction). It was found, that soil condition deteriorated by diskpan-compaction decreased the yield of maize significantly by 20 and 42% (w/w), and that of wheat by 13 and 15% (w/w) when compared to soils with no diskpan-compaction. Averaged over seven years, and three fertilizer levels, the cover % of the total, grass and perennial weeds on loosened soils were 73, 69 and 65% of soils contained diskpan-compaction

    Magnus Force in Discrete and Continuous Two-Dimensional Superfluids

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    Motion of vortices in two-dimensional superfluids in the classical limit is studied by solving the Gross-Pitaevskii equation numerically on a uniform lattice. We find that, in the presence of a superflow directed along one of the main lattice periods, vortices move with the superflow on fine lattices but perpendicular to it on coarse ones. We interpret this result as a transition from the full Magnus force in the Galilean-invariant limit to vanishing effective Magnus force in a discrete system, in agreement with the existing experiments on vortex motion in Josephson junction arrays.Comment: 6 pages, 7 figures; published in Phys. Rev.

    SOME AGRICULTURAL AND ECONOMIC ASPECTS OF ENERGY SAVING PRODUCTION TECHNOLOGIES OF MAIZE

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    The performance parameters, energetic characteristics and cost factors of direct drilling were evaluated by longterm trials carried out in Osztopán and Gödöllő regions. The effect of direct drilling, disking, ploughing, and soil loosening combined with disking and ploughing on the soil conditions, yields and cost factors was evaluated and based on the examination results. The economic comparisons were done by gross margin analyses of various technologies. Reducing the number of field applications is limited by the risk of soil compactions and weed infestations. From an economic part of view cost saving aspects of the various cultivation methods mentioned above cannot be justified in comparison with the ploughing methods. The lowest gross margin value was 61.79 EUR t-1, direct drilling and the highest was 67.34 EUR t-1, with ploughing but it was due to the great difference between the yield as well (6.89 and 4.03 t.ha-1). The results we achieved during our research are valid only in the given conditions, they could be recalculated and complemented under other soil and agro-ecological conditions. Our purpose was to emphasise the necessity of economical calculations before making decisions on changing technology. Our suggestion is: combined application of the traditional and energy saving methods, regarding the local conditions as well

    200 mm Sensor Development Using Bonded Wafers

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    Sensors fabricated from high resistivity, float zone, silicon material have been the basis of vertex detectors and trackers for the last 30 years. The areas of these devices have increased from a few square cm to 200 m2\> 200\ m^2 for the existing CMS tracker. High Luminosity Large Hadron Collider (HL-LHC), CMS and ATLAS tracker upgrades will each require more than 200 m2200\ m^2 of silicon and the CMS High Granularity Calorimeter (HGCAL) will require more than $600\ m^2.Thecostandcomplexityofassemblyofthesedevicesisrelatedtotheareaofeachmodule,whichinturnissetbythesizeofthesiliconsensors.Inadditiontolargearea,thedevicesmustberadiationhard,whichrequirestheuseofsensorsthinnedto200micronsorless.Thecombinationofwaferthinningandlargewaferdiameterisasignificanttechnicalchallenge,andisthesubjectofthiswork.Wedescribeworkondevelopmentofthinsensorson. The cost and complexity of assembly of these devices is related to the area of each module, which in turn is set by the size of the silicon sensors. In addition to large area, the devices must be radiation hard, which requires the use of sensors thinned to 200 microns or less. The combination of wafer thinning and large wafer diameter is a significant technical challenge, and is the subject of this work. We describe work on development of thin sensors on 200 mm$ wafers using wafer bonding technology. Results of development runs with float zone, Silicon-on-Insulator and Silicon-Silicon bonded wafer technologies are reported.Comment: 11 page

    Charge Collection and Electrical Characterization of Neutron Irradiated Silicon Pad Detectors for the CMS High Granularity Calorimeter

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    The replacement of the existing endcap calorimeter in the Compact Muon Solenoid (CMS) detector for the high-luminosity LHC (HL-LHC), scheduled for 2027, will be a high granularity calorimeter. It will provide detailed position, energy, and timing information on electromagnetic and hadronic showers in the immense pileup of the HL-LHC. The High Granularity Calorimeter (HGCAL) will use 120-, 200-, and 300-μm\mu\textrm{m} thick silicon (Si) pad sensors as the main active material and will sustain 1-MeV neutron equivalent fluences up to about 1016 neqcm210^{16}~\textrm{n}_\textrm{eq}\textrm{cm}^{-2}. In order to address the performance degradation of the Si detectors caused by the intense radiation environment, irradiation campaigns of test diode samples from 8-inch and 6-inch wafers were performed in two reactors. Characterization of the electrical and charge collection properties after irradiation involved both bulk polarities for the three sensor thicknesses. Since the Si sensors will be operated at -30 ^\circC to reduce increasing bulk leakage current with fluence, the charge collection investigation of 30 irradiated samples was carried out with the infrared-TCT setup at -30 ^\circC. TCAD simulation results at the lower fluences are in close agreement with the experimental results and provide predictions of sensor performance for the lower fluence regions not covered by the experimental study. All investigated sensors display 60%\% or higher charge collection efficiency at their respective highest lifetime fluences when operated at 800 V, and display above 90%\% at the lowest fluence, at 600 V. The collected charge close to the fluence of 1016 neqcm210^{16}~\textrm{n}_\textrm{eq}\textrm{cm}^{-2} exceeds 1 fC at voltages beyond 800 V.Comment: 36 pages, 34 figure

    Measurements of fiducial and differential cross sections for Higgs boson production in the diphoton decay channel at s√=8 TeV with ATLAS

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    Measurements of fiducial and differential cross sections are presented for Higgs boson production in proton-proton collisions at a centre-of-mass energy of s√=8 TeV. The analysis is performed in the H → γγ decay channel using 20.3 fb−1 of data recorded by the ATLAS experiment at the CERN Large Hadron Collider. The signal is extracted using a fit to the diphoton invariant mass spectrum assuming that the width of the resonance is much smaller than the experimental resolution. The signal yields are corrected for the effects of detector inefficiency and resolution. The pp → H → γγ fiducial cross section is measured to be 43.2 ±9.4(stat.) − 2.9 + 3.2 (syst.) ±1.2(lumi)fb for a Higgs boson of mass 125.4GeV decaying to two isolated photons that have transverse momentum greater than 35% and 25% of the diphoton invariant mass and each with absolute pseudorapidity less than 2.37. Four additional fiducial cross sections and two cross-section limits are presented in phase space regions that test the theoretical modelling of different Higgs boson production mechanisms, or are sensitive to physics beyond the Standard Model. Differential cross sections are also presented, as a function of variables related to the diphoton kinematics and the jet activity produced in the Higgs boson events. The observed spectra are statistically limited but broadly in line with the theoretical expectations

    Search for squarks and gluinos in events with isolated leptons, jets and missing transverse momentum at s√=8 TeV with the ATLAS detector

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    The results of a search for supersymmetry in final states containing at least one isolated lepton (electron or muon), jets and large missing transverse momentum with the ATLAS detector at the Large Hadron Collider are reported. The search is based on proton-proton collision data at a centre-of-mass energy s√=8 TeV collected in 2012, corresponding to an integrated luminosity of 20 fb−1. No significant excess above the Standard Model expectation is observed. Limits are set on supersymmetric particle masses for various supersymmetric models. Depending on the model, the search excludes gluino masses up to 1.32 TeV and squark masses up to 840 GeV. Limits are also set on the parameters of a minimal universal extra dimension model, excluding a compactification radius of 1/R c = 950 GeV for a cut-off scale times radius (ΛR c) of approximately 30
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