Search results for "Tact"

Optimal damping coefficient for a class of continuous contact models

2020

AbstractIn this study, we develop an analytical formula to approximate the damping coefficient as a function of the coefficient of restitution for a class of continuous contact models. The contact force is generated by a logical point-to-point force element consisting of a linear damper connected in parallel to a spring with Hertz force–penetration characteristic, while the exponent of deformation of the Hertz spring can vary between one and two. In this nonlinear model, it is assumed that the bodies start to separate when the contact force becomes zero. After separation, either the restitution continues or a permanent penetration is achieved. Therefore, this model is capable of addressing …

Metal/Semiconductor Barrier Properties of Non-Recessed Ti/Al/Ti and Ta/Al/Ta Ohmic Contacts on AlGaN/GaN Heterostructures

2019

This paper compares the metal/semiconductor barrier height properties of non-recessed Ti/Al/Ti and Ta/Al/Ta contacts on AlGaN/GaN heterostructures. Both contacts exhibited a rectifying behavior after deposition and after annealing at temperatures up to 550 &deg

Nonsmooth Mechanics. Convex and Nonconvex Problems

1999

Nonlinear, multivalued and possibly nonmonotone relations arise in several areas of mechanics. A multivalued or complete relation is a relation with complete vertical branches. Boundary laws of this kind connect boundary (or interface) quantities. A contact relation or a locking mechanism between boundary displacements and boundary tractions in elasticity is a representative example. Material constitutive relations with complete branches connect stress and strain tensors, or, in simplified theories, equivalent stress and strain quantities. A locking material or a perfectly plastic one is represented by such a relation. The question of nonmonotonicity is more complicated. One aspect concerns…

Anxiety and coping dispositions as predictors of the visual interaction between mother and child

1991

Abstract The “model of coping modes” distinguishes four dispositionally determined patterns of behavior (coping modes) which become apparent in stressful situations: repression, sensitization, nondefensiveness, and high anxiety. Following from this model, the present study is aimed at assessing associations between coping modes and children's looking behavior towards their mothers in a moderately stress-inducing laboratory setting. The visual exchange of 63 mothers and their eight- to 14-year-old children was observed during a ten-minute planning period for a Punch and Judy show which the child had to later perform. A close visual orientation toward the mother was registered for sensitizers…

Grafting and characterization of dodecylphosphonic acid on copper: Macro-tribological behavior and surface properties

2013

International audience; Thin film of n-dodecylphosphonic acid (DDPA) was prepared on a copper oxide substrate via a molecular self-assembly process. The composition, structure, organization, surface energy, morphology, and electrochemical behavior of the DDPA filmwere characterized bymeans of X-ray photoelectron spectroscopic analysis (XPS), polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS), contact angle measurement v(CAM), microscopic observations, and electrochemistry. The friction behavior of the DDPA film adsorbed on copper oxide substrate sliding against a Si3N4 ball was examined on a linear reciprocating tribological tester. Worn surfaces of the DDPA film…

“In situ” corneal and contact lens thickness changes with high resolution OCT

2012

Purpose: To show the utility of high resolution spectral domain optical coherence tomography (HR SOCT) for the in situ evaluation of epithelial, stromal and contact lens (CL) thickness changes under closed-eye conditions without lens removal. Settings: Clinical and Experimental Optometry Research Lab, University of Minho, Portugal. Methods: Eight young healthy patients wore a thick soft CL during 90 minutes under closed-eye conditions and measures of epithelial and stromal corneal thickness were obtained at regular intervals using a HR SOCT (Copernicus HR, Optopol Tech. SA, Poland). Results: Minimal changes in epithelial thickness were detected with a transient statistically significant inc…

Corneal aberrations pre and post-application of new contact lens in the astigmatism after penetrating keratoplasty.

2007

Factors influencing tourists’ intention to use COVID-19 contact tracing app

2020

AbstractThe purpose of this study was to develop and test a model that explores the antecedents of tourists’ acceptance of COVID-19 contact tracing app (CTA). Data was obtained from a crowdsourcing platform (Pollfish), in which 400 respondents answered the questionnaire. We used SmartPLS to analyse the data. Results reveal that trust and structural assurance have the strongest relationship. Furthermore, the relationship between trust and destination safety was positive. Finally, self-efficacy moderated the relationship between trust and intention, implying that trust was stronger for tourists who have higher levels of self-efficacy. Recommendations are offered.

Platinum chloride-based viability RT-qPCR for SARS-CoV-2 detection in complex samples.

2021

Isolation, contact tracing and restrictions on social movement are being globally implemented to prevent and control onward spread of SARS-CoV-2, even though the infection risk modelled on RNA detection by RT-qPCR remains biased as viral shedding and infectivity are not discerned. Thus, we aimed to develop a rapid viability RT-qPCR procedure to infer SARS-CoV-2 infectivity in clinical specimens and environmental samples. We screened monoazide dyes and platinum compounds as viability molecular markers on five SARS-CoV-2 RNA targets. A platinum chloride-based viability RT-qPCR was then optimized using genomic RNA, and inactivated SARS-CoV-2 particles inoculated in buffer, stool, and urine. Ou…

Research on Unrealistic Optimism among HoReCa Workers as a Possible Future Hotspot of Infections

2021

As we are facing a new surge of the highly infectious delta variant of COVID-19, there is an urgent need for research to reduce the harm before this next wave hits. In the present paper, we present data that is alarming. We have found that HoReCa (hotels, restaurants, and catering services) workers, who are highly exposed to many new social interactions in close contact, present an unrealistic optimism (UO) bias: they perceive themselves as less at risk to this virus in comparison to others. From the literature, we already know that individuals holding this view are less involved in preventive actions and present more risky behaviors. In the face of the delta variant, this leads to the conc…