Ti-Zr-Si-Nb nanocrystalline alloys and metallic glasses: Assessment on the structure, thermal stability, corrosion and mechanical properties

The development of novel Ti-based amorphous or \u3b2-phase nanostructured metallic materials could have significant benefits for implant applications, due to improved corrosion and mechanical characteristics (lower Young's modulus, better wear performance, improved fracture toughness) in comparison to the standardized \u3b1+\u3b2 titanium alloys. Moreover, the devitrification phenomenon, occurring during heating, could contribute to lower input power during additive manufacturing technologies. Ti-based alloy ribbons were obtained by melt-spinning, considering the ultra-fast cooling rates this method can provide. The titanium alloys contain in various proportions Zr, Nb, and Si (Ti60Zr10Si15Nb15, Ti64Zr10Si15Nb11, Ti56Zr10Si15Nb19) in various proportions. These elements were chosen due to their reported biological safety, as in the case of Zr and Nb, and the metallic glass-forming ability and biocompatibility of Si. The morphology and chemical composition were analyzed by scanning electron microscopy and energy-dispersive X-ray spectroscopy, while the structural features (crystallinity, phase attribution after devitrification (after heat treatment)) were assessed by X-ray diffraction. Some of the mechanical properties (hardness, Young's modulus) were assessed by instrumented indentation. The thermal stability and crystallization temperatures were measured by differential thermal analysis. High-intensity exothermal peaks were observed during heating of melt-spun ribbons. The corrosion behavior was assessed by electrocorrosion tests. The results show the potential of these alloys to be used as materials for biomedical applications

Plasma-wall interaction studies within the EUROfusion consortium: Progress on plasma-facing components development and qualification

This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014-2018 under grant agreement No 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission.The provision of a particle and power exhaust solution which is compatible with first-wall components and edge-plasma conditions is a key area of present-day fusion research and mandatory for a successful operation of ITER and DEMO. The work package plasma-facing components (WP PFC) within the European fusion programme complements with laboratory experiments, i.e. in linear plasma devices, electron and ion beam loading facilities, the studies performed in toroidally confined magnetic devices, such as JET, ASDEX Upgrade, WEST etc. The connection of both groups is done via common physics and engineering studies, including the qualification and specification of plasma-facing components, and by modelling codes that simulate edge-plasma conditions and the plasma-material interaction as well as the study of fundamental processes. WP PFC addresses these critical points in order to ensure reliable and efficient use of conventional, solid PFCs in ITER (Be and W) and DEMO (W and steel) with respect to heat-load capabilities (transient and steady-state heat and particle loads), lifetime estimates (erosion, material mixing and surface morphology), and safety aspects (fuel retention, fuel removal, material migration and dust formation) particularly for quasi-steady-state conditions. Alternative scenarios and concepts (liquid Sn or Li as PFCs) for DEMO are developed and tested in the event that the conventional solution turns out to not be functional. Here, we present an overview of the activities with an emphasis on a few key results: (i) the observed synergistic effects in particle and heat loading of ITER-grade W with the available set of exposition devices on material properties such as roughness, ductility and microstructure; (ii) the progress in understanding of fuel retention, diffusion and outgassing in different W-based materials, including the impact of damage and impurities like N; and (iii), the preferential sputtering of Fe in EUROFER steel providing an in situ W surface and a potential first-wall solution for DEMO.European Commission; Consortium for Ocean Leadership 633053; Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART

Mercury cadmium telluride : A superior choice for near room temperature infrared detectors (Review Paper)

"The advantages of mercury cadmium telluride (HgCdTe) for hot IR detector applications are discussed. Molecular beam epitaxy (MBE) is used to grow advanced device structures for this purpose. MBE offers the potential to grow HgCdTe heterostructure layers on large [7.62 cm (3 in.) or more] silicon substrates leading to very large format and high performance IR focal plane arrays in the future. Preliminary material and device properties achieved in p+-v-n+ device structures grown on 7.62 cm (3 in.) (211 )-oriented silicon wafers are discussed

Mercury cadmium telluride : A superior choice for near room temperature infrared detectors (Review Paper)

"The advantages of mercury cadmium telluride (HgCdTe) for hot IR detector applications are discussed. Molecular beam epitaxy (MBE) is used to grow advanced device structures for this purpose. MBE offers the potential to grow HgCdTe heterostructure layers on large [7.62 cm (3 in.) or more] silicon substrates leading to very large format and high performance IR focal plane arrays in the future. Preliminary material and device properties achieved in p+-v-n+ device structures grown on 7.62 cm (3 in.) (211 )-oriented silicon wafers are discussed

cAMP and cGMP in nasal mucus: relationships to taste and smell dysfunction, gender and age

Purpose: To evaluate the presence and concentration of cAMP and cGMP in human nasal mucus in normal volunteers, to relate these findings to age and gender, and to compare normal levels with those in patients with taste and smell dysfunction. Methods: Nasal mucus was collected over one to four days in 66 normal subjects and 203 patients with smell loss (hyposmia). Samples were centrifuged at 20,000 rpm, the supernatant removed and analyzed for cAMP and cGMP by using a 96 plate technique with a specific spectrophotometric colorimetric ELISA assay. Results: Both cAMP and cGMP were present in human nasal mucus with both cAMP and cGMP significantly higher in normal women than in normal men [men vs. women; cAMP, 0.23±0.002 vs. 0.34±0.05 (P < 0.05); cGMP, 0.28±0.03 vs. 0.63±0.12 (P < 0.01)]. Both cAMP and cGMP changed with age; both moieties increased in a U shaped, parabolic pattern reaching a peak at age 41-50 with cAMP diminishing thereafter and then increasing to its highest level over age 70. Both cAMP and cGMP were lower in patients with taste and smell dysfunction than in normal subjects [normals vs. patients; cAMP, 0.31±0.05 vs. 0.15±0.02 (P < 0.01); cGMP, 0.56±0.07 vs. 0.025±0.02 (P < 0.001)] suggesting a relationship to olfactory pathology. Conclusions: This is the first definitive study to demonstrate the presence of these cyclic nucleotides in nasal mucus and the first to reveal decreased levels in patients with impaired taste and smell function. Since olfactory receptor sensitivity decreases with age increased nasal mucus cAMP over age 70 may appear incongruous but suggests one role of cAMP in olfactory function may relate to feedback mechanism(s) whereby its increase over age 70 yr reflects a physiological attempt to enhance diminishing lfactory function through growth and development of olfactory receptor activity

cAMP and cGMP in nasal mucus related to severity of smell loss in patients with smell dysfunction

Purpose: To evaluate nasal mucus levels of cAMP and cGMP in patients with taste and smell dysfunction with respect to severity of their smell loss. Methods: cAMP and cGMP were measured in nasal mucus using a sensitive spectrophotometric 96 plate ELISA technique. Smell loss was measured in patients with taste and smell dysfunction by standardized psychophysical measurements of olfactory function and classified by severity of loss into four types from most severe to least severe such that anosmia > Type I hyposmia > Type II hyposmia > Type III hyposmia. Measurements of nasal mucus cyclic nucleotides and smell loss were made independently. Results: As smell loss severity increased stepwise cAMP and cGMP levels decreased stepwise [cAMP, cGMP (in pmol/ml); anosmia – 0.004, 0.008: Type I hyposmia – 0.12±0.03, 0.10±0.03: Type II hyposmia – 0.15±0.02, 0.16±0.01: Type III hyposmia – 0.23±0.05, 0.20±0.15]. Conclusions: These results confirm the association of biochemical changes in cyclic nucleotides with systematic losses of smell acuity. These results confirm the usefulness of the psychophysical methods we defined to determine the systematic classification of smell loss severity. These changes can form the basis for the biochemical definition of smell loss among some patients with smell loss as well as for their therapy

Wind loads on an azimuthal photovoltaic platform. Experimental study

Abstract. During the dimensioning stage of the embodiment design process of the azimuthal trackers for photovoltaic (PV) platforms a very important step is input load calculation. Wind load is the main load on these kinds of systems and a correct evaluation of wind load becomes significant for dimensioning. This paper presents results and conclusions from an experimental study on wind loads depending on wind velocity and functional positions of solar tracking platforms. The results are presented as graphic diagrams and can be useful for the improvement of actual standards on wind loads