929 research outputs found

    Coefficient of thermal expansion of nanostructured tungsten based coatings assessed by thermally induced substrate curvature method

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    The in plane coefficient of thermal expansion (CTE) and the residual stress of nanostructured W based coatings are extensively investigated. The CTE and the residual stresses are derived by means of an optimized ad-hoc developed experimental setup based on the detection of the substrate curvature by a laser system. The nanostructured coatings are deposited by Pulsed Laser Deposition. Thanks to its versatility, nanocrystalline W metallic coatings, ultra-nano-crystalline pure W and W-Tantalum coatings and amorphous-like W coatings are obtained. The correlation between the nanostructure, the residual stress and the CTE of the coatings are thus elucidated. We find that all the samples show a compressive state of stress that decreases as the structure goes from columnar nanocrystalline to amorphous-like. The CTE of all the coatings is higher than the one of the corresponding bulk W form. In particular, as the grain size shrinks, the CTE increases from 5.1 106^{-6} K1^{-1} for nanocrystalline W to 6.6 106^{-6} K1^{-1} in the ultra-nano-crystalline region. When dealing with amorphous W, the further increase of the CTE is attributed to a higher porosity degree of the samples. The CTE trend is also investigated as function of materials stiffness. In this case, as W coatings become softer, the easier they thermally expand.Comment: The research leading to these results has also received funding from the European Research Council Consolidator Grant ENSURE (ERC-2014-CoG No. 647554

    Thermomechanical properties of amorphous metallic tungsten-oxygen and tungsten-oxide coatings

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    In this work, we investigate the correlation between morphology, composition, and the mechanical properties of metallic amorphous tungsten-oxygen and amorphous tungsten-oxide films deposited by Pulsed Laser Deposition. This correlation is investigated by the combined use of Brillouin Spectroscopy and the substrate curvature method. The stiffness of the films is strongly affected by both the oxygen content and the mass density. The elastic moduli show a decreasing trend as the mass density decreases and the oxygen-tungsten ratio increases. A plateaux region is detected in correspondence of the transition between metallic and oxide films. The compressive residual stresses, moderate stiffness and high local ductility that characterize compact amorphous tungsten-oxide films make them promising for applications involving thermal or mechanical loads. The coefficient of thermal expansion is quite high (i.e. 8.9 \cdot 106^{-6} K1^{-1}), being strictly correlated to the amorphous structure and stoichiometry of the films. Under thermal treatments they show a quite low relaxation temperature (i.e. 450 K). They crystallize into the γ\gamma monoclinic phase of WO3_3 starting from 670 K, inducing an increase by about 70\% of material stiffness.Comment: The research leading to these results has also received funding from the European Research Council Consolidator Grant ENSURE (ERC-2014-CoG No. 647554). The views and opinions expressed herein do not necessarily reflect those of the European Commissio

    Effects of lockdown on emergency room admissions for psychiatric evaluation: an observational study from the AUSL Romagna, Italy

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    Objectives: An observation of the admissions to the emergency room (ER) requiring psychiatric evaluation during the lockdown and investigation of the demographic and clinical variables. Methods: Retrospective longitudinal observational study of ER accesses for psychiatric evaluation was performed, comparing two periods (9 March–3 May 2020 vs. 9 March–3 May 2019). Data (number of admissions, key baseline demographic and clinical variables) were extracted from the ER databases of referral centres in a well-defined geographic area of North-Eastern Italy (Cesena, Ravenna, Forlì, and Rimini). Results: A 15% reduction of psychiatric referrals was observed, together with a 17% reduction in the total number of patients referring to the ER. This reduction was most evident in the first month of the lockdown period (almost 25% reduction of both referrals and patients). Female gender (OR: 1.52: 95%, CI: 1.12–2.06) and being a local resident (OR: 1.54: 95%CI: 1.02–2.34) were factors associated with the decrease. Conclusions: Lockdown changed dramatically health priorities in the local population, including people with mental health. We speculate that our observations do not only refer to the confinement due to the lockdown regime but also to fear of contagion and adoption of different coping strategies, especially in women.Key-points During lockdown 15% reduction of psychiatric visits and >17% reduction in the number of psychiatric patients referring to the ER was observed. in the first four weeks of the lockdown almost 25% reduction of both visits and patients was observed Female gender and being a local resident were factors associated with the decrease

    Risk of Guillain-Barré syndrome after 2010–2011 influenza vaccination

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    Influenza vaccination has been implicated in Guillain Barré Syndrome (GBS) although the evidence for this link is controversial. A case–control study was conducted between October 2010 and May 2011 in seven Italian Regions to explore the relation between influenza vaccination and GBS. The study included 176 GBS incident cases aged ≥18 years from 86 neurological centers. Controls were selected among patients admitted for acute conditions to the Emergency Department of the same hospital as cases. Each control was matched to a case by sex, age, Region and admission date. Two different analyses were conducted: a matched case–control analysis and a self-controlled case series analysis (SCCS). Case–control analysis included 140 cases matched to 308 controls. The adjusted matched odds ratio (OR) for GBS occurrence within 6 weeks after influenza vaccination was 3.8 (95 % CI: 1.3, 10.5). A much stronger association with gastrointestinal infections (OR = 23.8; 95 % CI 7.3, 77.6) and influenza-like illness or upper respiratory tract infections (OR = 11.5; 95 % CI 5.6, 23.5) was highlighted. The SCCS analysis included all 176 GBS cases. Influenza vaccination was associated with GBS, with a relative risk of 2.1 (95 % CI 1.1, 3.9). According to these results the attributable risk in adults ranges from two to five GBS cases per 1,000,000 vaccinations

    The impact of COVID-19 quarantine on mental health: an observational study from an outpatient service for non-psychotic patients in Russia (Moscow)

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    We aimed to compare psychiatric hospital visits during the COVID-19 quarantine period with the same period in 2019, to reveal the predictors of underutilization of mental health services. We then investigated the fluctuation of telemedicine service during the quarantine period. The retrospective study included patients with non-psychotic mental disorders who consecutively visited the Moscow clinic. The number of outpatient visits, inpatient admissions, sociodemographic factors were analyzed. We assessed the sample within two periods -the "quarantine period" (March 30 -June 9, 2020) and "control period" (March 30 -June 9, 2019). Psychiatric visits decreased in older, retired and disabled persons, and increased among the unemployed. In multivariate analysis, the reduction became significant for the number of inpatient admissions. Telemedicine calls gradually increased from the start of the service, but decreased towards the end of the quarantine. In conclusion, referrals to outpatient and inpatient psychiatric services decreased during the quarantine period, with newly established TMS potentially compensating for that decrease. The strongest factor associated with visits during the pandemic is employment status

    Liquid hot isostatic pressing of QE22A magnesium alloy: a preliminary test

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    A preliminary experimental comparison of the behaviour of aluminium and magnesium alloys subjected to Liquid Hot Isostatic Pressing (LHIP) is proposed. The two metals melt at approximately the same temperature.However, as a consequence of a larger deformability of magnesium at elevated temperatures, the choice of LHIP parameters – and especially the temperature at which the pressure is applied – in the present exploratory case was constrained to values far smaller than those one would like to select in order to improve the ultimate tensile stress and the elongation to fracture

    The GINGER Project and status of the ring-laser of LNGS

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    A ring-laser attached to the Earth measures the absolute angular velocity of the Earth summed to the relativistic precessions, de Sitter and Lense-Thirring. GINGER (Gyroscopes IN GEneral Relativity) is a project aiming at measuring the LenseThirring effect with a ground based detector; it is based on an array of ring-lasers. Comparing the Earth angular velocity measured by IERS and the measurement done with the GINGER array, the Lense-Thirring effect can be evaluated. Compared to the existing space experiments, GINGER provides a local measurement, not the averaged value and it is unnecessary to model the gravitational field. It is a proposal, but it is not far from being a reality. In fact the GrossRing G of the Geodesy Observatory of Wettzell has a sensitivity very close to the necessary one. G ofWettzell is part of the IERS system which provides the measure of the Length Of the DAY (LOD); G provides information on the fast component of LOD. In the last few years, a roadmap toward GINGER has been outlined. The experiment G-GranSasso, financed by the INFN Commission II, is developing instrumentations and tests along the roadmap of GINGER. In this short paper the main activities of G-GranSasso and some results will be presented. The first results of GINGERino will be reported, GINGERino is the large ring-laser installed inside LNGS and now in the commissioning phase. Ring-lasers provide as well important informations for geophysics, in particular the rotational seismology, which is an emerging field of science. GINGERino is one of the three experiments of common interest between INFN and INGV

    Моделирование диффузии водорода по границам зерен в титане

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    В результате исследования было определено, что коэффициенты диффузии, полученные методом молекулярной динамики, подчиняются уравнению Аррениуса, т.е. с ростом температуры увеличивается и коэффициенты диффузии. Результаты расчетов согласуются с экспериментальными данными и другими расчетами. Результаты исследований могут быть полезны для исследователей, изучающих системы металл-водород, а также в области материаловедения, авиаконструкция и водородной энергетики. Кроме того, для теоретиков, работающих в области молекулярно-динамических расчетов, данные расчеты позволят оценить границы применимости используемого потенциала взаимодействия.As a result of the study, it was determined that the diffusion coefficients obtained by the molecular dynamics method obey the Arrhenius equation, i.e. With increasing temperature, the diffusion coefficients also increase. The results of the calculations are consistent with the experimental data and other calculations. The results of the research can be useful for researchers studying metal-hydrogen systems, as well as in the field of materials science, aircraft construction and hydrogen energy. In addition, for theorists working in the field of molecular dynamics calculations, these calculations will make it possible to estimate the limits of applicability of the interaction potential use

    Surgical repair of post-infarction ventricular free-wall rupture in the Netherlands: data from a nationwide registry

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    Background: Ventricular free-wall rupture (VFWR) is an infrequent but catastrophic complication of acute myocardial infarction (AMI). Most reports about outcome after surgical treatment are single-center experiences. We examined the early and mid-term outcomes after surgical repair of post-AMI VFWR using the Netherlands Heart Registration (NHR) database. Methods: We included data from NHR patients (>18 years old) who underwent surgery for post-AMI VFWR between 2014 and 2019. The primary end-point was in-hospital mortality. Secondary outcomes included postoperative complications and mid-term survival. Results: The study included 148 patients (54.7% male, mean age 66.5±11.1 years). Critical preoperative status was found in 62.6% of subjects. In-hospital mortality was 31.1% (46 of 148). Multivariable analysis identified female sex [odds ratio (OR), 5.49; 95% confidence interval (CI): 2.24–13.46] and critical preoperative status (OR, 4.06; 95% CI: 1.36–12.13) as independent predictors of in-hospital mortality. The overall median postoperative follow-up was 2.2 (interquartile range, 0.7–3.8) years. Overall survival rates at three and five years were 58.9% and 55.7%, respectively. Among hospital survivors, only 15 (14.7%) patients died during follow-up, with a five-year survival rate of 80.8%. Conclusions: In-hospital mortality after surgical repair of post-AMI VFWR is considerable. Female sex and preoperative critical status are independent predictors of early postoperative (in-hospital) death. Logistic EuroSCORE I can reliably predict in-hospital mortality (optimal cut-off >33%). Mid-term follow-up of patients surviving in-hospital course shows excellent results
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