Search results for "Fatigue"

Decrease in Serum Vitamin D Level of Older Patients with Fatigue

2019

Fatigue is characterized by reduced energy level, decreased muscle strength, and a variable degree of cognitive impairment. Recent evidences seem to link vitamin D deficiency to fatigue. The aim of this study was to assess and compare vitamin D status in a cohort of older subjects with and without fatigue. We recruited a total of 480 subjects, 240 patients with fatigue and 240 controls without fatigue, from the Cannizzaro Hospital of Catania (Italy). Fatigue severity was measured by the fatigue severity scale, whereas mental and physical fatigue were measured through the Wessely and Powell fatigue scale, respectively. We also measured several blood parameters and 25-OH vitamin D. Subjects w…

Changes in performance and poling kinetics during cross-country sprint skiing competition using the double-poling technique

2013

In this study, changes in skiing performance and poling kinetics during a simulated cross-country sprint skiing competition were investigated. Twelve elite male cross-country skiers performed simulated sprint competition (4 x 1,150 m heat with 20 min recovery between the heats) using the double-poling technique. Vertical and horizontal pole forces and cycle characteristics were measured using a force plate system (20-m long) during the starting spurt, racing speed, and finishing spurt of each heat. Moreover, heat and 20-m phase velocities were determined. Vertical and horizontal pole impulses as well as mean cycle length were calculated. The velocities of heats decreased by 2.7 +/- 1.7% (p …

Changes in the Association between European Workers’ Employment Conditions and Employee Well-Being in 2005, 2010 and 2015

2020

[EN] The aim of this paper is to study whether there is a change in the association between employment conditions and European employees' well-being at three different time points (the years 2005, 2010 and 2015), characterized by different socio-economic contexts. We based our study on the European Working Conditions Survey. Logistic regressions were performed by adjusting for gender, age, level of education, seniority, occupation, establishment size, activity sector and economic activity. Adjusted odds ratios (ORadj) and 95% confidence intervals (95% CI) are reported. In general, the association between employment conditions (type of employment contract, supervising, weekly working hours, …

Understanding mental fatigue and perception of effort to understand endurance performance

2015

Lettre à l'éditeur ("Journal of Applied physiology" vol.118, no.10). Fait partie de : "Commentaries on Viewpoint: The two-hour marathon: what's the equivalent for women?". http://jap.physiology.org/content/118/10/1324#ref-list-2

Conceptualisation et classification des problèmes de fatigue mécanique

2011

International audience; On propose de conceptualiser et de classifier les problèmes de calcul de structures dits de fatigue (dans le cadre de la Mécanique de lʼEndommagement). Parce que le concept de fatigue est avant tout un concept que lʼon peut estimer structural plutôt que local, cette classification est faite dʼabord sur des grandeurs structurales. Ensuite, on donne une classification faite sur des grandeurs locales. Lʼobjectif de ces classifications est de favoriser la résolution locale des problèmes de fatigue dʼune classe donnée en aidant à la justification du passage des lois dʼévolution obtenues par la Thermodynamique à celles écrites dans le cadre de la fatigue.

Characterization of rubberized asphalt for railway sub-ballast. Improvements in the mix-design, performance features and rational methodology of HMA_…

2018

(STR) can be incorporated into asphalt mixtures in two different methods, which are referred to as the wet-dry process. The blending of recycled rubber (CRM) with asphalt has been used for years, and several manufacturing processes have been developed in Europe as well as in the USA. The use of a bituminous sub-ballast layer has been pointed out as an exciting alternative to the granular sub-ballast design traditionally applied in most railroad tracks. Frequently, unbound granular materials are replaced by bituminous sub-ballast that provide additional benefits to the subgrade protection. Much research has been conducted on finding other alternative material to be used as a modifier in asph…

CHARACTERIZATION OF RUBBERIZED ASPHALT FOR RAILWAY SUB-BALLASTS

Tesi di dottorato sotto la supervisione del professore Gaetano di Mino del Dipartimento di Ingegneria Civile di Palermo), come borsista Marie-Curie all'interno del progetto SUPRITN 2013/2017. Il mio lavoro e la linea della ricerca riguarda i conglomerati bituminosi con granulato di gomma per lo strato di sub-ballast nelle linee ferroviarie. L’attività di ricerca comprende il mix-design dell’asfalto con aggiunta di gomma, la caratterizzazione e le prestazioni per la ferrovia in termini di comportamento meccanico e lo smorzamento delle vibrazioni. In particolare con l’avvento dell’alta velocità, diversi studi hanno evidenziato ottime caratteristiche fisico-meccaniche per ciò che riguarda il c…

Static strength and fatigue life of optimized hybrid single lap aluminum–CFRP structural joints

2017

Hybrid bolted/bonded joints are used to assemble structural components, commonly made by carbon fiber reinforced plastics (CFRP), with aluminum frames. Hence, they have become common solutions in a number of modern structural applications in the industrial fields, as well as civil constructions. Unfortunately, due to the lack of understanding of the relationships between the multiple parameters of influence that characterize their mechanical performance, only limited improvement have been achieved so far over classical bonding approaches, in terms of static and fatigue strength. As a result, further studies are needed in order to better exploit the potential of hybrid bolted/bonded joints a…

Infrared Thermography assisted evaluation of static and fatigue Mode II fracture toughness in FRP composites

2019

Abstract The work proposes the combined use of a Modified Transverse Crack Tension (MTCT) test coupon and Infrared Thermography, to evaluate the static and fatigue behaviour of Fibre Reinforced Polymer composites under Mode II delamination. Artificial delaminations starters are added to the TCT coupon, whose effects on the Strain Energy Release Rate are discussed. Infrared Thermography and Thermoelastic Stress Analysis are implemented to investigate stresses and delaminations growths on two FRP materials: a pre-preg IM7/8552 carbon fibre-epoxy and a glass-fibre reinforced epoxy laminates. The thermographic, thermoelastic and second harmonic signals have been obtained and used to monitor the…

Thermoelastic Stress Analysis of modified Transverse Cut Tensile composite specimens under pure Mode II fatigue delamination

2018

The present work investigates the behaviour of a Transvers Crack Tensile (TCT) specimen undergoing fatigue loading, by means of a Thermoelastic Stress Analysis (TSA) experimental setup. The TCT is a tensile composite specimen where a number of internal layers are cut through the beam width. The presence of such transverse notch favours the formation of interlaminar Mode II delaminations, starting from the notch tips and propagating between the cut and continuous plies. In this work, a modification is adopted to the classic TCT specimen, where insert films, mimicking artificial delaminations, are laid across the notch tips. This is done with the purpose to favour a pure Mode II and a symmetr…