Study of Snowboard Sandwich Structures

The aim of the present research is to extend the knowledge of mechanical properties both on single components and on complete structure employed for snowboard. Flexural and torsion tests are performed to acquire important comparison parameters between snowboard sandwich structures that differ for the core material employed (wood, PVC foam core). A simplified FEM model is proposed to simulate the flexural tests of the sandwich structure showing good predictive capability

Salt spray fog ageing of hybrid composite/metal rivet joints for automotive applications

The present experimental investigation aims to investigate the effect of salt-fog exposition on the mechanical behaviour of composite/metal riveted joints. To this aim, two kinds of joint were exposed to salt-fog environmental conditions according to ASTM B117 standard, for fifteen weeks. In particular, two composite laminates (i.e. glass fibre and carbon fibre/epoxy composites) were used as composite substrate joined with the metal substrate (i.e. aluminium alloy Al 6060). Single-lap shear tests were carried out in order to evaluate the evolution of the mechanical performances and the damage mechanisms of the riveted joints during the ageing exposition. The results evidence that the mechanical performances (i.e. maximum load and load-displacement slope) of the hybrid joints progressively decrease at increasing ageing time in the considered exposure time. Moreover, glass fibre/epoxy hybrid composite joint showed a higher sensitivity to degradation in salt-fog environmental condition than carbon fibre/epoxy one. As concerns the damage mechanisms, glass fibre/epoxy hybrid composite joint experienced catastrophic cleavage/net tension failure modes regardless the ageing time whereas the progressive bearing failure was the mechanism observed in carbon fibre/epoxy hybrid composite joint during the entire experimental campaign. Corrosion phenomena not significantly affected degradation performances of both joints

Electrical Properties of Silver Impurities and their Annealing Behaviour in p-Type Fz Silicon

The electrical activity of silver as well as its annealing properties in $10~\Omega$ cm p-type Fz silicon substrate are studied by means of the four-point probe and minority carrier lifetime measurements. Silver atom concentration in the range 10$^{14}$ to 10$^{15}$ cm$^{-3}$ consistently showed a donor type behaviour in the material and its presence led to a reduction of up to two orders of magnitude in the lifetime of minority carriers by the formation of deep-level traps. Isochronal annealing of silver contaminated specimens showed some gettering of the Ag impurities with resulting temperature dependent changes in the resistivity as well as the minority carrier lifetime values. Analysis of our results shows that a large fraction of the silver impurity atoms present forms the deep level defects and both the deep- and donor-levels appear to originate from the same source

Lifetime Measurements in Solar Cells of Different Thickness and in the Related Silicon Wafers

Abstract not availableNA-NOT AVAILABL

Magnetism research with polarized neutrons at the Centro di Studi Nucleari della Casaccia del C. N. E. N., Roma, Italy

Our group at the " Laboratorio di Fisica Nucleare Applicata " of C. N. E. N. since October 1961 has had in use the RC 1 Reactor (TRIGA Mark II). We had then to face the problem of performing some meaningful experiments which were not too severely handicapped by a low neutron flux. Consequently we decided to use polarized neutrons techniques for investigating ferromagnetic materials. At present two R. F. type polarized neutron spectrometers are in operation. In this review we summarize some work carried out at Casaccia in the field of magnetism.Le laboratoire des applications de la Physique Nucléaire du C. N. E. N. utilise, depuis octobre 1961, un réacteur RC 1 (Triga Mark II). Nous avons dû envisager des expériences qui ne seraient pas trop handicapées par le faible flux de neutrons. Aussi nous avons décidé d'utiliser la technique des neutrons polarisés pour l'étude des substances ferromagnétiques. Nous avons deux spectromètres à neutrons polarisés du type R. F. Dans cet article, nous résumons les travaux d'intérêt magnétique réalisés à Casaccia

Electrical properties of silver impurities and their annealing behaviour in p-type Fz silicon

The electrical activity of silver as well as its annealing properties in 10 \u3a9 cm p-type Fz silicon substrate are studied by means of the four-point probe and minority carrier lifetime measurements. Silver atom concentration in the range 1014to 1015cm-3consistently showed a donor type behaviour in the material and its presence led to a reduction of up to two orders of magnitude in the lifetime of minority carriers by the formation of deep-level traps. Isochronal annealing of silver contaminated specimens showed some gettering of the Ag impurities with resulting temperature dependent changes in the resistivity as well as the minority carrier lifetime values. Analysis of our results shows that a large fraction of the silver impurity atoms present forms the deep level defects and both the deep- and donor-levels appear to originate from the same source. \ua9 Les \uc9ditions de Physique 1996

The PDE4 Inhibitor Tanimilast Blunts Proinflammatory Dendritic Cell Activation by SARS-CoV-2 ssRNAs

Phosphodiesterase 4 (PDE4) inhibitors are immunomodulatory drugs approved to treat diseases associated with chronic inflammatory conditions, such as COPD, psoriasis and atopic dermatitis. Tanimilast (international non-proprietary name of CHF6001) is a novel, potent and selective inhaled PDE4 inhibitor in advanced clinical development for the treatment of COPD. To begin testing its potential in limiting hyperinflammation and immune dysregulation associated to SARS-CoV-2 infection, we took advantage of an in vitro model of dendritic cell (DC) activation by SARS-CoV-2 genomic ssRNA (SCV2-RNA). In this context, Tanimilast decreased the release of pro-inflammatory cytokines (TNF-α and IL-6), chemokines (CCL3, CXCL9, and CXCL10) and of Th1-polarizing cytokines (IL-12, type I IFNs). In contrast to β-methasone, a reference steroid anti-inflammatory drug, Tanimilast did not impair the acquisition of the maturation markers CD83, CD86 and MHC-II, nor that of the lymph node homing receptor CCR7. Consistent with this, Tanimilast did not reduce the capability of SCV2-RNA-stimulated DCs to activate CD4+ T cells but skewed their polarization towards a Th2 phenotype. Both Tanimilast and β-methasone blocked the increase of MHC-I molecules in SCV2-RNA-activated DCs and restrained the proliferation and activation of cytotoxic CD8+ T cells. Our results indicate that Tanimilast can modulate the SCV2-RNA-induced pro-inflammatory and Th1-polarizing potential of DCs, crucial regulators of both the inflammatory and immune response. Given also the remarkable safety demonstrated by Tanimilast, up to now, in clinical studies, we propose this inhaled PDE4 inhibitor as a promising immunomodulatory drug in the scenario of COVID-19