1,484 research outputs found

    A simulation of remote sensor systems and data processing algorithms for spectral feature classification

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    A computational model of the deterministic and stochastic processes involved in multispectral remote sensing was designed to evaluate the performance of sensor systems and data processing algorithms for spectral feature classification. Accuracy in distinguishing between categories of surfaces or between specific types is developed as a means to compare sensor systems and data processing algorithms. The model allows studies to be made of the effects of variability of the atmosphere and of surface reflectance, as well as the effects of channel selection and sensor noise. Examples of these effects are shown

    Baseline LHC machine parameters and configuration of the 2015 proton run

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    This paper shows the baseline LHC machine parameters for the 2015 start-up. Many systems have been upgraded during LS1 and in 2015 the LHC will operate at a higher energy than before and with a tighter filling scheme. Therefore, the 2015 commissioning phase risks to be less smooth than in 2012. The proposed starting configuration puts the focus on feasibility rather than peak performance and includes margins for operational uncertainties. Instead, once beam experience and a better machine knowledge has been obtained, a push in β∗\beta^* and performance can be envisaged. In this paper, the focus is on collimation settings and reach in β∗\beta^*---other parameters are covered in greater depth by other papers in these proceedings.Comment: submitted for publication in a CERN yellow report (Proceedings of the LHC Performance Workshop - Chamonix 2014

    The SPS as a Vacuum Test Bench for the Electron Cloud Studies with LHC Type Beams

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    The SPS machine has been operating with LHC-type beams with bunch intensities up to 8x1010 protons (70% of LHC nominal intensity). This paper will give evidence of the electron cloud phenomenon as the mechanism responsible for the pressure rises in the SPS in presence of LHC type beams. The dependence of the pressure rise and of the electron current measured with dedicated pick-ups on various beam characteristics such as proton bunch intensity, number of bunches needed to start the e-cloud phenomenon and the effect of missing bunches will be presented. The evolution of the pressure rise with the integrated current ('beam scrubbing') will be discussed. The observed effect of the dipole magnetic field and of the treatment of the stainless steel vacuum chambers with N2 glow discharge on the pressure rise and on its evolution with the integrated current will be also considered. Finally, the consequences of the electron cloud build-up on the SPS vacuum system for the LHC beam nominal intensity will be described

    Growth response of sorghum plants to chilling temperature and duration of exposure

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    Measurement of the optical parameters of a transfer line using multi-profile analysis

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    The standard approach to measure the optical parameters and the emittance in a transfer line is based on the analysis of the profiles measured by three monitors. This is feasible, provided the dispers ion function is known a priori. In this paper we propose to measure the complete set of five parameters (the two independent Twiss parameters, the emittance, the dispersion function and its derivative ) by using five monitors with one bending magnet interleaved. The results of some measurements carried out in the transfer line connecting the CERN PS and SPS rings are presented

    Coordination between plant and apex development in Hordeum vulgare ssp. distichum

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    Developmental scales for cereals describe apex and plant morphology separately. In order to link crucial steps of internal and external development, in three varieties of Hordeum vulgare spp. distichum L., sown in autumn and in spring, we recorded plant, leaf and apex stage, following the scales of Zadoks, Haun, and Banerjee and Wienhues, the number of primordia, culm and spike length, and the final number of leaves and spikelets. Primordia initiation was coordinated with leaf appearance and the relative rate was constant for the initiation of productive primordia. The maximum number of primordia was achieved just before the first node became detectable, but development was completed only by those initiated before floret differentiation and internode distension started. The first spikelet was initiated when the third leaf tip became visible, and the last one when plants were at the pseudo stem erection stage and five leaves had still to appear

    Earth feature identification for onboard multispectral data editing: Computational experiments

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    A computational model of the processes involved in multispectral remote sensing and data classification is developed as a tool for designing smart sensors which can process, edit, and classify the data that they acquire. An evaluation of sensor system performance and design tradeoffs involves classification rates and errors as a function of number and location of spectral channels, radiometric sensitivity and calibration accuracy, target discrimination assignments, and accuracy and frequency of compensation for imaging conditions. This model provides a link between the radiometric and statistical properties of the signals to be classified and the performance characteristics of electro-optical sensors and data processing devices. Preliminary computational results are presented which illustrate the editing performance of several remote sensing approaches

    The importance of root interactions in field bean/triticale intercrops

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    To highlight the contribution of belowground interactions to biomass and N and P yields, field bean and triticale were grown in a P-poor soil as sole crops and as replacement intercrops at two N levels. The shoots were always in contact, while the roots of adjacent rows were free to interact or were completely separated. This allowed simultaneous testing the intraspecific and interspecific competition between rows, which to our knowledge has not been studied before. Root biomass, distribution in soil, morphometry, and functional traits were determined, together with the nodule number and biomass. The Land Equivalent Ratio for shoot biomass and N and P yield were higher than 1 when roots were in contact, and markedly lower when they were separated. This demonstrates the positive contribution of root interactions, which in field bean, consisted of increased root elongation without changes in biomass and nutrient status; in triticale, of increased N and P uptake eciency and reduced biomass partitioning to roots. The soil-plant processes underlying intercrop advantage led to complementarity in N sources with low N inputs and facilitated N and P uptake with high N inputs, which demonstrates that intercropping could be profitable in both low and high input agriculture

    Post-anthesis accumulation and remobilization of dry matter, nitrogen and phosphorus in durum wheat as affected by soil type

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    The objective of the research was to quantify the changes in the accumulation of dry matter and N and P content of four durum wheat (Triticum durum Desf.) varieties grown on two soil types (sandy-loam and clay-loam), differing for texture, nitrogen content and water holding capacity. Plants were grown in containers and were rainfed until anthesis; irrigation was performed during grain filling to avoid water stress. The difference in total vegetative weight and nitrogen and phosphorus content of plants between anthesis and maturity was used to indirectly estimate the relative contribution of pre-anthesis assimilation and remobilization to grain yield. The behaviour of the four varieties was similar as they ranked in the same order for pre-anthesis and post-anthesis dry matter accumulation and grain yield and differences in soil characteristics induced similar changes in dry matter, N and P accumulation and remobilization. Soil type greatly affected the patterns of dry matter, N and P accumulation and remobilization. Plants grown on clay-loam soil had higher dry weight and N and P content both at anthesis and at maturity and higher grain yield at maturity, compared to plants grown on sandy-loam soil and the remobilization of dry matter, N and P were 75, 140 and 55% higher. Most of the grain carbohydrates originated from photosynthates produced during grain fill, as the contribution of remobilization of dry matter to grain yield did not reach 30%, while most of the grain N and P originated from the remobilization of N and P accumulated prior to anthesis as remobilization of N accounted for 73–82% of grain N content and remobilization of P accounted for 56–63% of grain P content
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