Acoustic emission testing of composite vessels under sustained loading

Acoustic emissions (AE) generated from Kevlar 49/epoxy composite pressure vessels subjected to sustained load-to-failure tests were studied. Data from two different transducer locations on the vessels were compared. It was found that AE from vessel wall-mounted transducers showed a wide variance from those for identical vessels subjected to the same pressure loading. Emissions from boss-mounted transducers did, however, yield values that were relatively consistent. It appears that the signals from the boss-mounted transducers represent an integrated average of the emissions generated by fibers fracturing during the vessel tests. The AE from boss-mounted transducers were also independent of time for vessel failure. This suggests that a similar number of fiber fractures must occur prior to initiation of vessel failure. These studies indicate a potential for developing an AE test procedure for predicting the residual service life or integrity of composite vessels

Lamp enables measurement of oxygen concentration in presence of water vapor

Open-electrode ultraviolet source lamp radiates sufficient energy at 1800 angstroms and 1470 angstroms for use in a double-beam, duel-wavelength oxygen sensor. The lamp is filled with xenon at a pressure of 100 mm of Hg

A systematic review of smart clothing in sports: Possible applications to extreme sports

Background. Traditional monitoring of athletes during sports has long been hampered by bulky, complicated and tethered systems. In the past decade, this has changed due to the miniaturization of sensors and improvement of systems to store and transmit data. These systems have been integrated into textiles to create ‘smart clothing’ which has been so ubiquitous that a review of the recent literature is crucial for understanding its full potential and potential use in extreme sports. Methods. An electronic data base search was performed from 2003 to April 2019 for full length articles including “Smart” AND “Clothing” OR “Clothing” AND “Sport(s)” written in English with human subjects. Articles were evaluated according to the Newcastle-Ottawa Scale. Results. Twenty-four studies resulted in 18 systems comprised of 22 types of clothing with various capabilities, including: monitoring heart rate, electromyography, respiratory rate, steps, GPS, energy expenditure, posture, body temperature and identifying the activity. Conclusions. Many types of smart clothing from socks and gloves, to pants, shirts and bras are increasingly utilized to monitor sports activity worldwide and gather previously unavailable, yet highly valuable data. This provides a unique opportunity to study athletes during training and competition, potentially providing more effective training and better safety protocols

Nuclear receptors and their coregulators in kidney

Nuclear receptors and their coregulators in kidney. Nuclear receptors are transcription factors that are essential in embryonic development, maintenance of differentiated cellular phenotypes, metabolism, and apoptosis. Dysfunction of nuclear receptor signaling leads to a wide spectra of proliferative, reproductive, and metabolic diseases, including cancers, infertility, obesity, and diabetes. In addition, many proteins have been identified as coregulators which can be recruited by DNA-binding nuclear receptors to affect transcriptional regulation. The cellular level of coregulators is crucial for nuclear receptor-mediated transcription and many coregulators have been shown to be targets for diverse intracellular signaling pathways and posttranslational modifications. This review provides a general overview of the roles and mechanism of action of nuclear receptors and their coregulators. Since progression of renal diseases is almost always associated with inflammatory processes and/or involve metabolic disorders of lipid and glucose, cell proliferation, hypertrophy, apoptosis, and hypertension, the importance of nuclear receptors and their coregulators in these contexts will be addressed

Hand-arm vibration in motocross: measurement and mitigation actions

SUMMARY Objective. This study focused on the quantification of vibration which reaches the hands of motocross riders and on the reduction of such vibration thanks to the handlebar and handlebar mounts. Background. Vibration transmitted through the hand and arm can lead to vascular and musculo- skeletal problems that are well documented in the scientific literature. Controlled studies identi- fying plate-handlebar characteristics effects on the vibration attenuation in motocross are lacking. Methods. We measured the vibration exposure of professional and recreational motocross riders on a motocross track and replicated the vibration patterns on a LDS V930 shaker in the laboratory, to analyze the effectiveness of various components in reducing the rider vibration exposure. Labo- ratory tests were performed with ten subjects randomly gripping different combinations of handle- bars and steering plates, and questionnaires were used to evaluate the comfort. Objective measure- ments of vibration reduction were then compared to the subjective values of perceived comfort. Results. According to the current EU legislation, the measured vibration levels reach the expo- sure limit in less than 1h. The mechanical characteristics of the handlebars and steering plates have a limited effect on the vibration transmitted to the rider’s hands. The rubber elements that many manufacturers use to reduce the vibration have limited effects at frequencies that are harmful for the musculoskeletal system. Questionnaires results have no correlation with the measured plate and handlebar performances. Conclusions. Most of the techniques used to reduce the hand-arm vibration exposure of moto- cross drivers are ineffective