206 research outputs found

    Modelling Photovoltaic Panels (Tandem) In Matlab-Simulink

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    At the stage of development of solar photovoltaic; the direct conversion of energy carried by the solar radiation into electricity, but before consuming, it took to produce using solar panels. Modeling of solar cells is based on their electrical characteristics (relationship voltage / current) under various conditions of radiation and temperature obtained by the equivalent circuit model, we consider associations with cells semiconductors respectful individuals such as: if, AlGaAs, Tandem, we integrate this model with Matlab simulink. The aim of this work is modeled solar panels; Tandem (coupled AlGaAs / Si). This modeling is an essential step to evaluate the characteristics of photovoltaic solar panels

    Effect of population density and dose of nitrogen and potassium fertilizers on performance of green bean (Phaseolus vulgaris)

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    This experiment was executed in a split randomized complete block design with three replications. Two plant densities (D), (D1; D2) equal to one plant and two plants per pot and seven fertilizers doses (F), (N0 K0; N1 K0; N1 K1; N2 K0; N2 K2; N0 K1; N0 K2) were investigated. N0, N11 and N2 equal to 0, 0.46, and 0.92 g urea while, K0, K1 and K2 equal to 0, 0.42 and 0.84 g potassium sulfate,  respectively. The results showed that the treatments had no effect on the number of  branches per plant and vice versa the interaction. Lower plant density (D1) and higher dose of both elements (N2 K2) significantly increased shoots dry weight, number of pods and pod yield per plant while, in second season the higher value of those yield parameters was obtained at lower dose of nitrogen (N1 K0), the interaction of those treatments increased significantly plant dry weight. The  interaction between lower plant density (D1) and nitrogen irrespective of their quantity and potassium, (N1 K0; N1 K1; N2 K0 and N2 K2) increased the number of pods and pods yield per plant, while the greatest yield per hectare was obtained at density planting (D2) receiving higher doses of both fertilizer and lower dose of nitrogen (N2 K2: N1 K0) at the first and second season respectively.Keywords: Cultivar Djadida; Nutrient Competition; Vegetative Productivity

    The Role of Mirror Dichroic in Tandem Solar Cell GaAs/Si

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    The good choice of the mirror dichroic between two solar cells was key to the development of the first two-terminal monolithic, multi-junction solar cell. In this paper describes a simulation for mirror dichroic between the first cell (GaAs) and second cell (Si ). In the simulation, Spectrum of the mirror Issued to first cell is changed the 0.3 ?m to0.6 ?m and the rest of the spectrum turns to the second cell. the By varying the mirror dichroic was demonstrate in the form of current-voltage(I-V) characteristics and quantum efficiency (QE). Keywords: multi-junction, mirror dichroic, quantum efficiency

    The LYRA Instrument Onboard PROBA2: Description and In-Flight Performance

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    The Large Yield Radiometer (LYRA) is an XUV-EUV-MUV (soft X-ray to mid-ultraviolet) solar radiometer onboard the European Space Agency PROBA2 mission that was launched in November 2009. LYRA acquires solar irradiance measurements at a high cadence (nominally 20 Hz) in four broad spectral channels, from soft X-ray to MUV, that have been chosen for their relevance to solar physics, space weather and aeronomy. In this article, we briefly review the design of the instrument, give an overview of the data products distributed through the instrument website, and describe the way that data are calibrated. We also briefly present a summary of the main fields of research currently under investigation by the LYRA consortium

    Contribution to Collaborative Innovation Studies: Cases of SMES Moroccan Automotive Suppliers and their Client

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    The aim of this work is to study how collaborative innovation succeeds between a large enterprise and SME relationship (Manufacturer-Equipment) in automotive supply chain using case studies. Data were collected from semi-structured interviews with managers in nine firms. The main intention was to understand how these companies engaged collaborative innovation and what the factors were to make it successful. The study adopted a qualitative approach in the study of these factors. The results show the importance of the internal capacities of SMEs (management style, innovation capacities, knowledge management ...) in the success and valorization of such a project. The study provides important lessons on how these relationships can impact the way businesses operate and how they innovate

    Poorly differentiated thyroid carcinoma: a retrospective clinicopathological study

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    Poorly differentiated thyroid carcinoma (PDTC) is an independent thyroid cancer histotype. In spite of its scarcity, it represents the main cause of death from non-anaplastic follicular cell-derived thyroid cancer. However, given the newness of this entity, few data are available on its clinical behaviour and no explicit consensus sets its treatment. To report the experience of a tertiary medical centre in morocco with PDTC over a period of 7 years. Retrospective study selecting all patients treated for thyroid carcinoma in Nuclear Medicine Department of a tertiary medical centre in Casablanca over seven years period. Patient's files were reviewed for background data, clinico-pathological characteristics, treatment and outcome. Seven patients were included in the study. Patient's average age was 60 years old (30-81) including six women and one man. All patients underwent a total thyroidectomy completed by cervical lymph node dissection in 57% of cases. Mean primary tumour size was 4cm (1-9cm). Patients were classified pT3 in 70% of cases, pT1 and pT2 in 15% each. Vascular invasion was found in 85% of cases. Pathological subtypes found were "insular carcinoma" in 85% of cases. Radioiodine therapy (RIT) was indicated in all cases. Follow-up period ranged between 10 months and 6 years. It showed a complete remission in 57% of cases, persistent disease in 28% of cases and a progressive disease in 15% of cases with a local recurrence. To date, the survival rate is 85%. PDTC is an aggressive thyroid cancer histotype. Treatment remains surgical followed by RIT if the tumour is radioavid. Multimodality therapy is indicated depending on the case and close monitoring is always indicated given the high risk of relapse

    In-flight performance of the solar UV radiometer LYRA/PROBA-2

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    LYRA is a solar radiometer, part of the PROBA-2 micro-satellite payload (Fig. 1). The PROBA-2 [1] mission has been launched on 02 November 2009 with a Rockot launcher to a Sun-synchronous orbit at an altitude of 725 km. Its nominal operation duration is two years with possible extension of 2 years. PROBA-2 is a small satellite developed under an ESA General Support Technology Program (GSTP) contract to perform an in-flight demonstration of new space technologies and support a scientific mission for a set of selected instruments [2]. PROBA-2 host 17 technological demonstrators and 4 scientific instruments. The mission is tracked by the ESA Redu Mission Operation Center. One of the four scientific instruments is LYRA that monitors the solar irradiance at a high cadence (> 20 Hz) in four soft X-Ray to VUV large passbands: the “Lyman-Alpha” channel, the “Herzberg” continuum range, the “Aluminium” and “Zirconium” filter channels. The radiometric calibration is traceable to synchrotron source standards [3]. LYRA benefits from wide bandgap detectors based on diamond. It is the first space assessment of these revolutionary UV detectors for astrophysics. Diamond sensors make the instruments radiation-hard and solar-blind (insensitive to the strong solar visible light) and, therefore, visible light blocking filters become superfluous. To correlate the data of this new detector technology, silicon detectors with well known characteristics are also embarked. Due to the strict allocated mass and power budget (5 kg, 5W), and poor priority to the payload needs on such platform, an optimization and a robustness of the instrument was necessary. The first switch-on occured on 16 November 2009. Since then the instrument performances have been monitored and analyzed during the commissioning period. This paper presents the first-light and preliminary performance analysis

    Eclipses observed by LYRA - a sensitive tool to test the models for the solar irradiance

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    We analyze the light curves of the recent solar eclipses measured by the Herzberg channel (200-220 nm) of the Large Yield RAdiometer (LYRA) onboard PROBA-2. The measurements allow us to accurately retrieve the center- to-limb variations (CLV) of the solar brightness. The formation height of the radiation depends on the observing angle so the examination of the CLV provide information about a broad range of heights in the solar atmosphere. We employ the 1D NLTE radiative transfer COde for Solar Irradiance (COSI) to model the measured light curves and corresponding CLV dependencies. The modeling is used to test and constrain the existing 1D models of the solar atmosphere, e.g. the temperature structure of the photosphere and the treatment of the pseudo- continuum opacities in the Herzberg continuum range. We show that COSI can accurately reproduce not only the irradiance from the entire solar disk, but also the measured CLV. It hence can be used as a reliable tool for modeling the variability of the spectral solar irradiance.Comment: 19 pages, 9 figures, Solar Physic

    Detection of Solar Rotational Variability in the LYRA 190 - 222 nm Spectral Band

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    We analyze the variability of the spectral solar irradiance during the period from 7 January, 2010 until 20 January, 2010 as measured by the Herzberg channel (190-222 nm) of the Large Yield RAdiometer (LYRA) onboard PROBA2. In this period of time observations by the LYRA nominal unit experienced degradation and the signal produced by the Herzberg channel frequently jumped from one level to another. Both these factors significantly complicates the analysis. We present the algorithm which allowed us to extract the solar variability from the LYRA data and compare the results with SORCE/SOLSTICE measurements and with modeling based on the Code for the Solar Irradiance (COSI)

    Minimal Information for Studies of Extracellular Vesicles 2018 (MISEV2018): A Position Statement of the International Society for Extracellular Vesicles and Update of the MISEV2014 Guidelines

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    The last decade has seen a sharp increase in the number of scientific publications describing physiological and pathological functions of extracellular vesicles (EVs), a collective term covering various subtypes of cell-released, membranous structures, called exosomes, microvesicles, microparticles, ectosomes, oncosomes, apoptotic bodies, and many other names. However, specific issues arise when working with these entities, whose size and amount often make them difficult to obtain as relatively pure preparations, and to characterize properly. The International Society for Extracellular Vesicles (ISEV) proposed Minimal Information for Studies of Extracellular Vesicles (“MISEV”) guidelines for the field in 2014. We now update these “MISEV2014” guidelines based on evolution of the collective knowledge in the last four years. An important point to consider is that ascribing a specific function to EVs in general, or to subtypes of EVs, requires reporting of specific information beyond mere description of function in a crude, potentially contaminated, and heterogeneous preparation. For example, claims that exosomes are endowed with exquisite and specific activities remain difficult to support experimentally, given our still limited knowledge of their specific molecular machineries of biogenesis and release, as compared with other biophysically similar EVs. The MISEV2018 guidelines include tables and outlines of suggested protocols and steps to follow to document specific EV-associated functional activities. Finally, a checklist is provided with summaries of key points
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