8,530 research outputs found
A force balance system for the measurement of skin friction drag force in the presence of large vibrations and temperatures
Design of counterbalance system for skin friction drag measurements on hypersonic vehicle
Investigation of Systems and Techniques for Multicomponent Microforce Measurements on Wind Tunnel Models Semiannual Status Report, 15 Jul. 1965 - 15 Jan. 1966
Skin friction drag sensor and multicomponent microforce wind tunnel balance syste
Development of a 1.6-kW, 2000-volt, high- frequency dc-dc converter for ion thrustors using a modular design and an inductive energy pumping technique for conversion, regulation and protection Summary report
High-frequency dc-dc converter for ion thrustors using modular design and inductive energy pumping technique for conversion, regulation, and protectio
Small perturbation dynamics of the neuromuscular system in tracking tasks
Small perturbation dynamics of neuromuscular system in tracking task
RTCC requirements for mission G - Trajectory computers for TLI and MCC processors, part 1 Final report
Functional properties of trajectory computers for translunar injection and midcourse correction procedures on lunar orbit
Multi-component Force Balance Control Systems Final Report
Technique and apparatus for drag, lift, and pitch force measurements in hypersonic wind tunnel
Acute Effects Of 24-h Sleep Deprivation On Salivary Cortisol And Testosterone Concentrations And Testosterone To Cortisol Ratio Following Supplementation With Caffeine Or Placebo
International Journal of Exercise Science 10(1): 108-120, 2017. Caffeine has become a popular ergogenic aid amongst athletes and usage to improve athletic performance has been well documented. The effect of caffeine on anabolic and catabolic hormones in a sleep-deprived state has had little investigation to date. The purpose of the current study was to investigate the potential of caffeine to offset the effects, if any, of short-term sleep deprivation and exercise on an athlete’s testosterone and cortisol concentrations via salivary technique. Eleven competitive male athletes volunteered to be part of this prospective double-blinded study. Three test days were scheduled for each athlete; one non-sleep deprived, one sleep-deprived with caffeine supplementation (6 mg.kg-1) and one sleep-deprived with placebo ingestion. Sleep deprivation was defined as 24-h without sleep. Each test day was composed of 2 aerobic components: a modified Hoff test and a Yo-Yo test. Testosterone and cortisol concentrations were measured via salivary analysis at 4 different time-points; T1 to T4, representing baseline, and pre- and post-aerobic components, respectively. Overall no significant differences were detected comparing the different sleep states for testosterone or cortisol concentrations. A trend existed whereby the sleep-deprived with caffeine ingestion state mirrored the non-sleep deprived state for cortisol concentration. Therefore, caffeine supplementation may have potential benefits for athletes during short-term aerobic exercise when sleep-deprived. An increase in mean testosterone concentration post-aerobic exercise was only observed in the sleep-deprived with caffeine ingestion state
Real-time all-optical ultrasound imaging of a dynamic heart valve phantom
All-optical ultrasound imaging, in which ultrasound is generated and received using light, is well-suited to minimally invasive surgical procedures. Here we present a device that can provide real-time M-mode ultrasound images, and demonstrate its use imaging a dynamic heart valve phantom. This device, comprising two optical fibres, one with a graphene-polydimethylsiloxane composite coating for ultrasound generation, and a second with a concave Fabry-Perot cavity for ultrasound reception, had a diameter of 30 MHz) that enabled imaging with high axial resolution ( 2 cm). M-mode imaging with an A-line rate of 100 Hz was demonstrated on a heart valve phantom with realistic mitral valve motion. This work demonstrates the potential for all-optical ultrasound imaging to be used for guidance of intracardiac interventions
Ecology of a North Sea pockmark with an active methane seep
ABSTRACT: At a large North Sea pockmark, with active methane seeps, surface sediments were found
to have higher insoluble sulphide concentrations than sedlments from the surrounding area. The fauna
of the pockmark was characterized by 2 species which have not pi-evlously been reported from the
Fladen Ground in the northern North Sea. These species were a b~valve, Thyasira sarsi (which is known
to contain endosymbiotic sulphur-oxidising bacteria) and a mouthless and gutless nematode,
Astomonerna sp., which also contains endosymbiotic bacteria The nematode was the dominant
meiofauna species in the pockmark sediments. Both macro-lnfauna and total nematodes were in low
abundance in samples taken from the base of the pockmark. Sediment samples from the pockmark
contained numerous otoliths, implying that substantial winnowing of the sediment had taken place.
This was supported by studies on the sulphide concentrations in the sediment which showed multiple
layering of the sediments on the sides of the pockmark, suggesting displacement. The carbon isotope
compositions (6I3c) of the tissues of benthic animals from in and around the pockmark were generally in
the range -16 to -2O%, indicating that little methane-derived carbon was contributing to their
nutrition. T sarsi had the most 13c-depleted tissues, -31.4 to -35.1 L, confirming the nutritional dependence of this species on chemoautotrophic bacteria that utilize reduced sulphur
The Design of a Skin Friction Meter for Use in Extreme Environmental Conditions Final Report
High altitude, high temperature meter system for skin friction measurement on flying hypersonic ramje
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