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

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 10$^{-6}$ K$^{-1}$ for nanocrystalline W to 6.6 10$^{-6}$ K$^{-1}$ 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

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 $\cdot$ 10$^{-6}$ K$^{-1}$), 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 $\gamma$ monoclinic phase of WO$_3$ 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

Gendered L1 attrition and L2 acquisition of pitch range in Japanese-English sequential bilinguals

This project investigated pitch range production in Japanese-English female and male sequential bilinguals. This language combination was chosen because high pitch level has been claimed to index femininity in Japanese (Ohara, 2019) whereas in English an increase in pitch level is used to index friendliness by both females and males (Loveday, 1981). Data were collected through a reading task and voicemail task from 19 Japanese-English bilinguals in London (UK), 21 Japanese-English bilinguals in Tokyo (JP), 15 Japanese monolinguals in Tokyo and 16 English monolinguals in London (49 females vs 21 males). In both tasks, speech was directed to an imaginary addressee varying in formality and sex. Of interest was to examine the extent to which Japanese and English influenced one another with regard to L1 attrition and L2 acquisition. The effect of individual gender identity on pitch range was investigated to assess whether, e.g., female bilinguals who closely identified with femininity would produce a high pitch level. In the reading task, Japanese female and male monolinguals produced significantly higher f0 maximum and wider pitch span than English monolinguals, irrespective of addressee. Regarding L1 attrition, bilingual males produced a significantly lower f0min in their Japanese than the Japanese monolingual males, suggesting a restructuring of the L1. Regarding L2 acquisition, English f0 mean and f0 maximum of the female bilinguals was significantly higher than that of the English females, suggesting an influence from Japanese on English. Additionally, English f0 mean was lower for both female bilinguals who rated themselves as more masculine and male bilinguals who rated themselves as more feminine on the English gender questionnaire. These results were not replicated in semi-spontaneous speech. Summarising, gender-specific patterns of L1 attrition and L2 acquisition were evidenced with regard to read speech, but not semi-spontaneous speech. This suggests that the formality of read speech might enhance the production of language and gender normative pitch range and that individual gender identity might have been expressed alternatively in semi-spontaneous speech

Verbano

L’obiettivo del progetto è la soluzione del problema Verbano tramite la scelta di una nuova regolazione e di oppurtuni interventi strutturali. Tale soluzione deve tendere a minimizzare i danni causati da eventi alluvionali tanto a monte quanto a valle, i danni indotti dalla mancata fornitura idrica agli utenti irrigui ed idroelettrici di valle e quelli subiti dalla navigazione e dal turismo quando si deprimono eccessivamente i livelli lacuali, senza trascurare, nel contempo, il mantenimento di un deflusso minimo nel Ticino, a valle dello sbarramento del Panperduto. In tale ricerca si dovranno ovviamente tener conto dei vincoli posti dalla capacità di smaltimento delle portate all’incile del lago e dalla necessità di mantenere attiva la sua naturale funzione di laminazione in occasione di eventi alluvionali che interessino anche il Po

LDL receptor expression on T lymphocytes in old patients with Down syndrome

BACKGROUND: In Down syndrome patients several metabolic abnormalities have been reported, some involving the lipid metabolism. The level of LDL in plasma is the major determinant of the risk of vascular disease. There appear to be no studies on the LDL receptor in Down syndrome patients. METHODS: Flow cytometric methods for measuring the LDL receptor in peripheral blood mononuclear cells (PBMC) can identify patients with hypercholesterolemia. We applied this method in 19 old patients with Down syndrome and 23 healthy controls. RESULTS: Down syndrome patients had high levels of triglycerides and low levels of HDL, and high levels of CRP. We also found a down-regulation of LDL receptor expression. CONCLUSIONS: Down syndrome patients show no increase in the frequency of cardiovascular disease. The low incidence in cardiovascular disease despite the low level of HDL, high levels of CRP and reduction of LDL receptor expression lead to the conclusion that either these are not risk factors in these patients or that other risks factors – not yet identified – are considerably lower

Bulk Cr tips for scanning tunneling microscopy and spin-polarized scanning tunneling microscopy

A simple, reliable method for preparation of bulk Cr tips for Scanning Tunneling Microscopy (STM) is proposed and its potentialities in performing high-quality and high-resolution STM and Spin Polarized-STM (SP-STM) are investigated. Cr tips show atomic resolution on ordered surfaces. Contrary to what happens with conventional W tips, rest atoms of the Si(111)-7x7 reconstruction can be routinely observed, probably due to a different electronic structure of the tip apex. SP-STM measurements of the Cr(001) surface showing magnetic contrast are reported. Our results reveal that the peculiar properties of these tips can be suited in a number of STM experimental situations