202 research outputs found

    A new lab facility for measuring bidirectional reflectance/emittance distribution functions of soils and canopies

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    Recently, a laboratory measurement facility has been realized for assessing the anisotropic reflectance and emittance behaviour of soils, leaves and small canopies under controlled illumination conditions. The facility consists of an ASD FieldSpec 3 spectroradiometer covering the spectral range from 350 – 2500 nm at 1 nm spectral sampling interval. The spectroradiometer is deployed using a fiber optic cable with either a 1°, 8° or 25° instantaneous field of view (IFOV). These measurements can be used to assess the plant pigment (chlorophyll, xanthophyll, etc.) and non-pigment system (water, cellulose, lignin, nitrogen, etc.). The thermal emittance is measured using a NEC TH9100 Infrared Thermal Imager. It operates in a single band covering the spectral range from 8 – 14 mm with a resolution of 0.02 K. Images are 320 (H) by 240 (V) pixels with an IFOV of 1.2 mrad. A 1000 W Quartz Tungsten Halogen (QTH) lamp is used as illumination source, approximating the radiance distribution of the sun. This one is put at a fixed position during a measurement session. Multi-angular measurements are achieved by using a robotic positioning system allowing to perform either reflectance or emittance measurements over almost a complete hemisphere. The hemisphere can be sampled continuously between 0° and 80° from nadir and up to a few degrees from the hot-spot configuration (depending on the IFOV of the measurement device) for a backscattering target. Measurement distance to targets can be varied between 0.25 and 1 m, although with a distance of more than 0.6 m it is not possible to cover the full hemisphere. The goal is to infer the BRDF (bidirectional reflectance distribution function) and BTDF (bidirectional thermal distribution function) from these multi-angular measurements for various surface types (like soils, agricultural crops, small tree canopies and artificial objects) and surface roughness. The steering of the robotic arm and the reading of the spectroradiometer and the thermal camera are all fully automated

    Ketenkwaliteit in de hand

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    Binnen de voedseltechnologie is het van belang te weten hoe goed een keten in staat is de kwaliteit van het versproduct vast te houden. Om inzicht te krijgen in de prestatie van een keten is de 'vers-keten prestatie-index' ontwikkeld, waarvan in het kort wordt uitgelegd hoe deze te gebruike

    2-Thiabicyclo[3.2.0]hepta-3,6-Dienes. 3. Desulfuration and Sulfuration of 2-Thiabicyclo[3.2.0]hepta-3,6-Dienes and X-Ray Crystal Structure of 3a,6,7,8,9,9a-Hexahydro-3a,5-Dimethylthieno[3,2-B][2]benzothiophene-2,3-Dicarbonitrile

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    The 2-3.2.0] hepta-3,6-Dienes 1–7 Extrude Sulfur in Solution at 285 °C to Give the 1,2-Benzenedicarbonitriles 8–12 in Yields of 42–56%. 5-(1,1-Dimethylethyl)-3,6-Dimethyl-2-3.2.0] hepta-3,6-Diene-1,7-Dicarbonitrile (6) Reacts at 140 °C to Give a Mixture of the Cope-Rearranged Isomer 13, the 1,2-Benzenedicarbonitrile 11, and possibly a 3a,6a-Dihydrothieno[3,2-B] thiophene (14). Reaction of 2a,5,6,7,8,8a-Hexahydro-2a,4-Dimethylbenzo[C]cyclobuta[B]thiophene-L,2-Dicarbonitrile (15) at 140 °C Gives a Mixture of De8ulfurated (16) and Sulfureted (17) Products in Yields of 88% and 70%, Respectively. Single-Crystal X-Ray Analysis Proved the 3a,6,7,8,9,9a-Hexahydrothieno[3,2-B][2]benzothiophene Structure (17). the Possible Mechanism of the Insertion of Sulfur in the Carbon-Carbon Single Bond of 15 is Discussed. © 1982, American Chemical Society. All Rights Reserved

    Charged-Particle Multiplicities in Charged-Current Neutrino-- and Anti-Neutrino--Nucleus Interactions

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    The CHORUS experiment, designed to search for ΜΌ→Μτ\nu_{\mu}\to\nu_{\tau} oscillations, consists of a nuclear emulsion target and electronic detectors. In this paper, results on the production of charged particles in a small sample of charged-current neutrino-- and anti-neutrino--nucleus interactions at high energy are presented. For each event, the emission angle and the ionization features of the charged particles produced in the interaction are recorded, while the standard kinematic variables are reconstructed using the electronic detectors. The average multiplicities for charged tracks, the pseudo-rapidity distributions, the dispersion in the multiplicity of charged particles and the KNO scaling are studied in different kinematical regions. A study of quasi-elastic topologies performed for the first time in nuclear emulsions is also reported. The results are presented in a form suitable for use in the validation of Monte Carlo generators of neutrino--nucleus interactions.Comment: 17 pages, 5 figure

    Leading order analysis of neutrino induced dimuon events in the CHORUS experiment

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    We present a leading order QCD analysis of a sample of neutrino induced charged-current events with two muons in the final state originating in the lead-scintillating fibre calorimeter of the CHORUS detector. The results are based on a sample of 8910 neutrino and 430 antineutrino induced opposite-sign dimuon events collected during the exposure of the detector to the CERN Wide Band Neutrino Beam between 1995 and 1998. % with EÎŒ1,EÎŒ2>5E_{\mu 1},E_{\mu 2} > 5 GeV and Q2>3Q^2 > 3 GeV2^2 collected %between 1995 and 1998. The analysis yields a value of the charm quark mass of \mc = (1.26\pm 0.16 \pm 0.09) \GeVcc and a value of the ratio of the strange to non-strange sea in the nucleon of Îș=0.33±0.05±0.05\kappa = 0.33 \pm 0.05 \pm 0.05, improving the results obtained in similar analyses by previous experiments.Comment: Submitted to Nuclear Physics

    The data acquisition system of the CHORUS experiment

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    In the years 1994-1998 the CHORUS Collaboration has recorded data in the CERN WA95 experiment. Here we describe the data acquisition system that has been used, featuring concurrent hierarchical state machines, a remote operating system, a buffer manager, a dispatcher, a control panel and a supervisor

    Associated Charm Production in Neutrino-Nucleus Interactions

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    In this paper a search for associated charm production both in neutral and charged current Îœ\nu-nucleus interactions is presented. The improvement of automatic scanning systems in the {CHORUS} experiment allows an efficient search to be performed in emulsion for short-lived particles. Hence a search for rare processes, like the associated charm production, becomes possible through the observation of the double charm-decay topology with a very low background. About 130,000 Îœ\nu interactions located in the emulsion target have been analysed. Three events with two charm decays have been observed in the neutral-current sample with an estimated background of 0.18±\pm0.05. The relative rate of the associated charm cross-section in deep inelastic Îœ\nu interactions, σ(ccˉΜ)/σNCDIS=(3.62−2.42+2.95(stat)±0.54(syst))×10−3\sigma(c\bar{c}\nu)/\sigma_\mathrm{NC}^\mathrm{DIS}= (3.62^{+2.95}_{-2.42}({stat})\pm 0.54({syst}))\times 10^{-3} has been measured. One event with two charm decays has been observed in charged-current ΜΌ\nu_\mu interactions with an estimated background of 0.18±\pm0.06 and the upper limit on associated charm production in charged-current interactions at 90% C.L. has been found to be σ(ccˉΌ−)/σCC<9.69×10−4\sigma (c\bar{c} \mu^-)/\sigma_\mathrm{CC} < 9.69 \times 10^{-4}.Comment: 10 pages, 4 figure

    The data acquisition system of the CHORUS experiment

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    In the years 1994--1998 the CHORUS Collaboration has recorded data in the CERN WA95 experiment. Here we describe the data acquisition system that has been used, featuring concurrent hierarchical state machines, a remote operating system, a buffer manager, a dispatcher, a control panel and a supervisor

    The CHORUS neutrino oscillation search experiment

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    The CHORUS experiment has successfully finished run I (320~000 recorded \numu\ CC in 94/95) and performed half of run II (225~000 \numu\ CC in 96). The analysis chain was exercised on a small data sample for the muonic \tdecay\ search using for the first time fully automatic emulsion scanning. This pilot analysis, resulting in a limit \sintth \leq 3 \cdot 10^{-2}, confirms that the CHORUS proposal sensitivity (\sintth \leq 3 \cdot 10^{-4}) is within reach in two years
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