45 research outputs found

    Effects of different needles and substrates on CuInS2 deposited by electrostatic spray deposition

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    Copper indium disulphide (CuInS2) thin films were deposited using the electrostatic spray deposition method. The effects of applied voltage and solution flow rate on the aerosol cone shape, film composition, surface morphology and current conversion were investigated. The effect of aluminium substrates and transparent fluorine doped tin oxide (SnO2:F) coated glass substrates on the properties of as-deposited CuInS2 films were analysed. An oxidation process occurs during the deposition onto the metallic substrates which forms an insulating layer between the photoactive film and substrate. The effects of two different spray needles on the properties of the as-deposited films were also studied. The results reveal that the use of a stainless steel needle results in contamination of the film due to the transfer of metal impurities through the spray whilst this is not seen for the glass needle. The films were characterised using a number of different analytical techniques such as X-ray diffraction, scanning electron microscopy, Rutherford back-scattering and secondary ion mass spectroscopy and opto-electronic measurements

    Maximum dynamic response of linear elastic SDOF systems based on an evolutionary spectral model for thunderstorm outflows

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    The study aims to estimate the maximum dynamic response of linear elastic SDOF systems subjected to thunderstorm outflows. Starting from a recently developed Evolutionary Power Spectral Density (EPSD) model for the wind velocity, the dynamic response is decomposed into a time-varying mean and a non-stationary random fluctuation. The EPSD and the Non-Geometrical Spectral Moments (NGSMs) of the random fluctuation are derived both accounting and neglecting the transient dynamics due to the modulating function of the load. The mean value of the maximum nonstationary fluctuating component of the response is estimated based on the definition of an equivalent stationary process following an approach proposed in the literature. In order to mitigate the overestimations of the maximum dynamic response due to the Poisson approximation, analogously to the formulation developed by Der Kiureghian for withe noise excitation, an equivalent expected frequency is introduced for thunderstorm excitation. Finally, the maximum dynamic response to thunderstorms is estimated as the sum of the maximum mean and fluctuating parts and a numerical validation of the results against real recorded thunderstorms is provided, highlighting the reliability of adding up the mean and fluctuating contributions and the advantages and limits of neglecting the transient dynamics

    Effect of cooling rate on phase transformation in 6-8 wt % YSZ APS TBCs

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    In properly produced as-sprayed thermal barrier coatings of yttria partially stabilized zirconia (7YSZ) the only phase that can be found is the metastable tetragonal prime structure t’. Even though t’ is sometimes called “not transformable”, because it behaves as practically stable up to rather high temperature, long term exposure much above 1200 °C produces its equilibrium transformation in tetragonal and cubic phases. During cooling down to room temperature the tetragonal phase will transform in monoclinic one. Although it is considered a martensitic transformation, fast cooling after prolonged high temperature exposure (over 1300°C) can avoid or limit the evolution from tetragonal to monoclinic structure. The effect of the cooling rate on this transformation has been investigated in free standing TBCs both with porous microstructure and dense vertically cracked one, exposed at 1400°C for 100 hours. The samples have been analysed by XRD and subsequent Rietveld refinement analysis to quantify the phase content: the results highlight that different cooling rates give different monoclinic contents, confirming the cooling rate effect on the transformation. If the phase equilibrium was not achieved due to fast cooling, it could be restored at low temperature for short duration independent of cooling rate. It was demonstrated that after exposure at 1400°C followed by fast cooling, the equilibrium phase composition could be achieved by a low temperature heat treatment of 12h at 200°C. For validation, the quantitative phase analysis has been performed before and after that low temperature heat treatment. Moreover the unit cell volume per each phase has been measured, for both samples at equilibrium and samples after fast cooling. Therefore the strain induced by the volume increase due to monoclinic phase formation has been calculated and compared with TBC maximum allowable strain

    Propuesta de atención a pacientes diabéticos utilizando un sistema de telemonitoreo

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    RESUMENEste artículo contiene los razonamientos y pautas para la implementación de una herramienta de comunicación móvil para el monitoreo y atención de pacientes con diabetes. También muestra en qué procesos el monitoreo a distancia facilita la atención y cuidado por parte del personal médico de una manera no presencial y así garantizar el mejor cuidado posible para los afectados por esta enfermedad.ABSTRACTThis article contains the thoughts and guidelines for the implementation of a mobile communication tool in monitoring and care of patients with diabetes. It also shows how the remote monitoring process provides the attention and care from medical personnel in a non-face and thus ensures the best possible care for those affected by this disease

    A clinical trial of oral hyposensitization in systemic allergy to nickel.

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    Nickel allergy is the most common contact allergy. Some nickel-sensitive patients present systemic (cutaneous and/or digestive) symptoms related to the ingestion of high nickel-content foods, which significantly improve after a specific low nickel-content diet. The etiopathogenetic role of nickel in the genesis of systemic disorders is, furthermore, demonstrated by the relapse of previous contact lesions, appearance of widespread eczema and generalized urticaria-like lesions after oral nickel challenge test. The aim of this study is to investigate the safety and efficacy of a specific oral hyposensitization to nickel in patients with both local contact disorders and systemic symptoms after the ingestion of nickel-containing foods. Inclusion criteria for the recruitment of these patients were (other than a positive patch test) a benefit higher than 80% from a low nickel-content diet and a positive oral challenge with nickel. Based on the previous experiences, our group adopted a therapeutic protocol by using increasing oral doses of nickel sulfate associated to an elimination diet. Results have been excellent: this treatment has been effective in inducing clinical tolerance to nickel-containing foods, with a low incidence of side effects (gastric pyrosis, itching erythema)

    MOCVD of ultra-thin PV solar cell devices using a pyrite based p-i-n structure

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    Ultra-thin photovoltaic (PV) devices were produced by atmospheric pressure metal organic chemical vapour deposition (AP-MOCVD) incorporating a highly absorbing intermediate sulphurised FeSₓ layer into a CdS/CdTe structure. X ray diffraction (XRD) confirmed a transitional phase change to pyrite FeS₂ after post growth sulphur (S) annealing of the FeSₓ layer between 400⁰C and 500⁰C. Devices using a superstrate configuration incorporating a sulphurised or non sulphurised FeSₓ layer were compared to p-n devices with only a CdS/CdTe structure. Devices with sulphurised FeSₓ layers performed least efficiently, even though pyrite fractions were present. Rutherford back scattering (RBS) confirmed deterioration of the CdS/FeSₓ interface due to S inter-diffusion during the annealing process

    Severe asthma: One disease and multiple definitions

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    Severe asthma: One disease and multiple definitions

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    Introduction: There is, so far, no universal definition of severe asthma. This definition usually relies on: number of exacerbations, inhaled therapy, need for oral corticosteroids, and respiratory function. The use of such parameters varies in the different definitions used. Thus, according to the parameters chosen, each patient may result in having severe asthma or not. The aim of this study was to evaluate how the choice of a specific definition of severe asthma can change the allocation of patients. Methods: Data collected from the Severe Asthma Network Italy (SANI) registry were analyzed. All the patients included were then reclassified according to the definitions of U-BIOPRED, NICE, WHO, ATS/ERS, GINA, ENFUMOSA, and TENOR. Results: 540 patients, were extracted from the SANI database. We observed that 462 (86%) met the ATS/ERS criteria as well as the GINA criteria, 259 (48%) the U-Biopred, 222 (41%) the NICE, 125 (23%) the WHO, 313 (58%) the Enfumosa, and 251 (46%) the TENOR criteria. The mean eosinophil value were similar in the ATS/ERS, U-Biopred, and Enfumosa (528, 532 and 516 cells/mcl), higher in WHO and Tenor (567 and 570 cells/mcl) and much higher in the NICE classification (624 cells/mcl). Lung function tests resulted similarly in all groups, with WHO (67%) and ATS/ERS-GINA (73%), respectively, showing the lower and upper mean FEV1 values. Conclusions: The present observations clearly evidence the heterogeneity in the distribution of patients when different definitions of severe asthma are used. However, the recent definition of severe asthma, provided by the GINA document, is similar to that indicated in 2014 by ATS/ERS, allowing mirror reclassification of the patients examined. This lack of homogeneity could complicate the access to biological therapies. The definition provided by the GINA document, which reflects what suggested by ATS/ERS, could partially overcome the problem

    An evolutionary power spectral density model of thunderstorm outflows consistent with real-scale time-history records

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    This paper presents a new approach for modelling the evolutionary power spectral density (EPSD) of thunderstorm outflows based on a database of 129 real-scale thunderstorm time-histories. Two equivalent methods of decomposition of the wind velocity are investigated, outlining the derivation of the EPSD. The analyses are based on the hypothesis that the residual turbulent fluctuations can be treated as a uniformly modulated process, whose reliability is verified studying the steadiness of its up-crossing rate. The assumption of considering a constant turbulence intensity is checked through the evaluation of the dynamic response of a set of SDOF systems in time-domain and through the response spectrum technique. Two models for the time-modulating function of the EPSD are proposed that include the parameters characteristic of both the thunderstorm event and the background wind. Finally, the steps for the derivation of the EPSD are outlined pointing out the limits of the representation of the PSD of the reduced turbulent fluctuations through spectral models commonly adopted in wind engineering. The final aim of this research is finalising a triad of complementary methods for evaluating the dynamic response of structures to thunderstorm outflows - EPSD, time-domain and response spectrum - consistent with real-scale time-history records
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