23 research outputs found

    Growth and Physical Structure of Amorphous Boron Carbide Deposited by Magnetron Sputtering on a Silicon Substrate with a Titanium Interlayer

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    Multilayer amorphous boron carbide coatings were produced by radiofrequency magnetron sputtering on silicon substrates. To improve the adhesion, titanium interlayers with different thickness were interposed between the substrate and the coating. Above three hundreds nanometer, the enhanced roughness of the titanium led to the growth of an amorphous boron carbide with a dense and continuing columnar structure, and no delamination effect was observed. Correspondingly, the adhesion of the coating became three time stronger than in the case of a bare silicon substrate. Physical structure and microstructural proprieties of the coatings were investigated by means of a scan electron microscopy, atomic force microscopy and X-ray diffraction. The adhesion of the films was measured by a scratch tester

    Growth and Physical Structure of Amorphous Boron Carbide Deposited by Magnetron Sputtering on a Silicon Substrate with a Titanium Interlayer

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    Multilayer amorphous boron carbide coatings were produced by radiofrequency magnetron sputtering on silicon substrates. To improve the adhesion, titanium interlayers with different thickness were interposed between the substrate and the coating. Above three hundreds nanometer, the enhanced roughness of the titanium led to the growth of an amorphous boron carbide with a dense and continuing columnar structure, and no delamination effect was observed. Correspondingly, the adhesion of the coating became three time stronger than in the case of a bare silicon substrate. Physical structure and microstructural proprieties of the coatings were investigated by means of a scan electron microscopy, atomic force microscopy and X-ray diffraction. The adhesion of the films was measured by a scratch tester

    Production Strategies of TiNx Coatings via Reactive High Power Impulse Magnetron Sputtering for Selective H2 Separation

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    This scientific work aims to optimize the preparation of titanium nitride coatings for selective H-2 separation using the Reactive High Power Impulse Magnetron Sputtering technology (RHiPIMS). Currently, nitride-based thin films are considered promising membranes for hydrogen. The first series of TiNx/Si test samples were developed while changing the reactive gas percentage (N-2%) during the process. Obtained coatings were extensively characterized in terms of morphology, composition, and microstructure. A 500 nm thick, dense TiNx coating was then deposited on a porous alumina substrate and widely investigated. Moreover, the as-prepared TiNx films were heat-treated in an atmosphere containing hydrogen in order to prove their chemical and structural stability; which revealed to be promising. This study highlighted how the RHiPIMS method permits fine control of the grown layer's stoichiometry and microstructure. Moreover, it pointed out the need for a protective layer to prevent surface oxidation of the nitride membrane by air and the necessity to deepen the study of TiNx/alumina interface in order to improve film/substrate adhesion

    Surface Optimization of Commercial Porous Ti Substrates by EPD of Titanium Nitride

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    In this work, the infiltration of TiN powders by electrophoretic deposition (EPD) in aqueous media was considered as alternative method to reduce the size craters and the roughness of commercial porous Ti substrates. Ti substrates can be used as suitable supports for the deposition of dense hydrogen separation TiNx-based membranes by physical vapor deposition (PVD) techniques. The influence of various EPD deposition parameters on surface morphology and roughness of TiN-infiltrated substrates were investigated in order to optimize their surface properties. The results suggest that a multi-step EPD procedure is an effective technique for reducing substrate surface defects of commercial porous Ti substrates which could then be successfully used as proper supports for the deposition of dense and defect-free TiNx layers, also aligning the thermal mismatch between the active layer and the porous substrate

    Microwave assisted sintering of Na-β’’-Al2O3 in single mode cavities: Insights in the use of 2450 MHz frequency and preliminary experiments at 5800 MHz

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    Microwave assisted sintering of Na-beta’’-Al2O3 in single mode cavities was accurately investigated. The use of single mode cavity allowed monitoring the parameters affecting the sintering process, like the forward power, together with the temperature evolution, making possible to perform energy efficiency and specific energy consumption evaluations. Experiments have been performed at the frequency of 2450 MHz, but preliminary results are also reported using the higher frequency of 5800 MHz, in order to investigate its effect on important parameters like the power density distribution as well as the penetration depth, which are responsible of the resulting heating rate and sintering outcome. Dielectric properties of the powders were measured as a function of temperature in order to partially predict and support the understanding of their experimental heating behaviour. Furthermore, dielectric properties provide the fundamental information needed for the multiphysics numerical simulation, performed with the aim to reach insights into the power density evolution in the specimen as sintering proceeds

    Measuring empathy in pediatrics: validation of the Visual CARE measure

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    Background: Empathy is a key element of “Patient and Family Centered Care”, a clinical approach recommended by the American Academy of Pediatrics. However, there is a lack of validated tools to evaluate paediatrician empathy. This study aimed to validate the Visual CARE Measure, a patient rated questionnaire measuring physician empathy, in the setting of a Pediatric Emergency Department (ED). Methods: The empathy of physicians working in the Pediatric ED of the University Hospital of Udine, Italy, was assessed using an Italian translation of the Visual Care Measure. This test has three versions suited to different age groups: the 5Q questionnaire was administered to children aged 7–11, the 10Q version to those older than 11, and the 10Q–Parent questionnaire to parents of children younger than 7. The internal reliability, homogeneity and construct validity of the 5Q and 10Q/10Q–Parent versions of the Visual Care Measure, were separately assessed. The influence of family background on the rating of physician empathy and satisfaction with the clinical encounter was also evaluated. Results: Seven physicians and 416 children and their parents were included in the study. Internal consistency measured by Cronbach’s alpha was 0.95 for the 10Q/10Q–Parent versions and 0.88 for the 5Q version. The item-total correlation was > 0.75 for each item. An exploratory factor analysis showed that all the items load onto the first factor. Physicians’ empathy scores correlated with patients’ satisfaction for both the 10Q and 10Q–Parent questionnaires (Spearman’s rho = 0.7189; p < 0.001) and for the 5Q questionnaire (Spearman’s rho = 0.5968; p < 0,001). Trust in the consulting physician was lower among immigrant parents (OR 0.43. 95% CI 0.20–0.93). Conclusions: The Visual Care Measure is a reliable second-person test of physician empathy in the setting of a Pediatric Emergency Room. More studies are needed to evaluate the reliability of this instrument in other pediatric settings distinct from the Emergency Room and to further evaluate its utility in measuring the impact of communication and empathy training programmes for healthcare professionals working in pediatrics

    Un lattante che fa i calcoli

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    The paper presents the case of a four-month-old infant with a history of crying spells, vomit and renal stones on ultrasounds. Urinary excretion of dibasic amino acids and genetic study confirm a digenic cystinuria. The presented case shows that clinical features of nephrolithiasis in infants could be non-specific and the diagnosis challenging. Chronic renal failure is a possible complication of cystinuria and is positively related to the duration of the disease and treatment delay. Early diagnosis and treatment of cystinuria is essential in children to maintain a normal renal function and reduce the risk of end-stage renal disease in the more aggressive forms

    Oxidation and Thermal Shock Resistance of AlTiN Ceramic Thin Coating Deposited by Magnetron Sputtering (Hipims) on Ti-48Al-2Cr-2Nb Intermetallic Alloy

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    The intermetallic alloy Ti-48Al-2Cr-2Nb is used for fabrication of low pressure turbine blades, because its good mechanical properties, low density and oxidation resistance at high temperature. However, the alloy application is still limited by significant oxidation above 850 °C. A thin AlTiN ceramic coating of about 3 µm, applied by magnetron spattering, can improve the surface oxidation resistance of this intermetallic alloy. The objective of this work is to investigate the integrity and oxidation resistance of TiAlN coating after thermal cycling under oxidizing atmosphere at temperatures up to 850°C and 950°C. Thermal cycling was performed in a burner rig specifically designed to simulate the operating conditions of turbine engine components
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