15,335 research outputs found
EV space suit gloves (passive)
A pair of pressure and thermal insulating overgloves to be used with an Extravehicular (EV) suit assembly was designed, developed, fabricated, and tested. The design features extensive use of Nomex felt materials in lieu of the multiple layer insulation formerly used with the Apollo thermal glove. The glove theoretically satisfies all of the thermal requirements. The presence of the thermal glove does not degrade pressure glove tactility by more than the acceptable 10% value. On the other hand, the thermal glove generally degrades pressure glove mobility by more than the acceptable 10% value, primarily in the area of the fingers. Life cycling tests were completed with minimal problems. The thermal glove/pressure glove ensemble was also tested for comfort; the test subjects found no problems with the thermal glove although they did report difficulties with pressure points on the pressure glove which were independent of the thermal glove
Destruction of chain-superconductivity in YBa_2Cu_4O_8 in a weak magnetic field
We report measurements of the temperature dependent components of the
magnetic penetration depth {\lambda}(T) in single crystal samples of
YBa_2Cu_4O_8 using a radio frequency tunnel diode oscillator technique. We
observe a downturn in {\lambda}(T) at low temperatures for currents flowing
along the b and c axes but not along the a axis. The downturn in {\lambda}_b is
suppressed by a small dc field of ~0.25 T. This and the zero field anisotropy
of {\lambda}(T) likely result from proximity induced superconducting on the CuO
chains, however we also discuss the possibility that a significant part of the
anisotropy might originate from the CuO2 planes.Comment: 5 page
Optic nerve head segmentation
Reliable and efficient optic disk localization and segmentation are important tasks in automated retinal screening. General-purpose edge detection algorithms often fail to segment the optic disk due to fuzzy boundaries, inconsistent image contrast or missing edge features. This paper presents an algorithm for the localization and segmentation of the optic nerve head boundary in low-resolution images (about 20 /spl mu//pixel). Optic disk localization is achieved using specialized template matching, and segmentation by a deformable contour model. The latter uses a global elliptical model and a local deformable model with variable edge-strength dependent stiffness. The algorithm is evaluated against a randomly selected database of 100 images from a diabetic screening programme. Ten images were classified as unusable; the others were of variable quality. The localization algorithm succeeded on all bar one usable image; the contour estimation algorithm was qualitatively assessed by an ophthalmologist as having Excellent-Fair performance in 83% of cases, and performs well even on blurred image
Feasibility of a chemical poison loop system
Chemical poison loop system for reactivity control of tungsten water moderated rocket reacto
Development and Use of Color Standards for Egg Yolks
Abstract FOR SOME YEARS poultry scientists have been engaged in nutrition studies on the effects of various grains fed to laying birds. Some of these studies have been concerned with the effect of grain or combinations of grains in determining yolk color. The desired yolk color for home use varies with the geographical location and customs of the people, but in general a fairly light color is preferred. On the other hand users of yolks such as noodle manufacturers and cake bakers pay premium prices for dark colored yolk. It is therefore more profitable for the egg producer if he accurately maintains the yolk color within the desired range for his particular market. Since verbal color descriptions are ambiguous it is necessary to have standards for egg yolk colors in recording and communicating the results of poultry diet research. The only color chart available in Canada was one which had been
Brief Abstracts of some Papers on Seeding Agents
During the preparation of a work plan for a study of the atmospheric water resources in Utah, a number of publications were studied which presented information pertaining to agents used to modify weather. These publications have been compiled to eliminate repetition of this laborious task. Brief abstracts of these papers were prepared to help investigators determine whether or not they wish to see the original publications
Nestling diet, secondary sexual traits and fitness in the zebra finch
We examined the effect of nestling diet quality on a suite of physiological, morphological and life-history
traits in adult male zebra finches,Taeniopygia guttata. Compared with birds reared on a supplemented diet,
nestlings reared on a seed-only diet showed a reduced rate of growth and reduced cell-mediated immune function as measured by an in vivo response to aT lymphocyte-dependent mitogen. There were no differences between birds reared on the two diets in any of the following adult traits: body size, primary sexual traits (testes mass, numbers of stored sperm, sperm function, velocity and morphology), secondary sexual traits (beak colour and song rate), serological traits or immunological traits. The only differences we detected were a lower body mass and a greater proportion of individuals with plumage abnormalities among those reared on a seed-only diet (this latter effect was transient). The fact that male zebra finches reared on a seed-only diet were, as adults, virtually indistinguishable from those reared on a supple-
mented diet, despite having reduced growth and immune function as nestlings, demonstrates that they
subsequently compensated through the di¡erential allocation of resources. Our results indicate that differ-
ential allocation is costly in terms of fitness since birds reared on a seed-only diet experienced a significantly greater mortality rate than those reared on a supplemented diet. This in turn suggests the existence of a trade-of between the development of traits important for reproduction, such as primary and secondary sexual traits and longevity
A comparison of underwater visual distance estimates made by scuba divers and a stereo-video system: Implications for underwater visual census of reef fish abundance
Underwater visual census of reef fish by scuba divers is a widely used and useful technique for assessing the composition and abundance of reef fish assemblages, but suffers from several biases and errors. We compare the accuracy of underwater visual estimates of distance made by novice and experienced scientific divers and an underwater stereo-video system. We demonstrate the potential implications that distance errors may have on underwater visual census assessments of reef fish abundance. We also investigate how the accuracy and precision of scuba diver length estimates of fish is affected as distance increases. Distance was underestimated by both experienced ( mean relative error = -11.7%, s.d. = 21.4%) and novice scientific divers (mean relative error = -5.0%, s. d. =17.9%). For experienced scientific divers this error may potentially result in an 82% underestimate or 194% overestimate of the actual area censused, which will affect estimates of fish density. The stereo-video system also underestimated distance but to a much lesser degree (mean relative error = -0.9%, s.d. = 2.6%) and with less variability than the divers. There was no correlation between the relative error of length estimates and the distance of the fish away from the observer
Passenger acceptance of counter-terrorism security measures in stations
Terrorist attacks pose a serious threat to the EU, particularly in public transport (PT) hubs such as railway stations due to their level of accessibility and where the individual passenger security screening methods used in airports are impractical. Consequently, methods of increasing station resilience against terrorist attacks in Europe have been explored as part of the recent SecureStation project. To support this work, PT passengers from across Europe were surveyed to gauge their opinion on current counter-terrorism security measures in stations and the acceptability and perceived effectiveness of potential security enhancements. The results, from a total sample of 489 respondents, provide indications of passenger priorities, their opinions of current station security, the acceptability of different security measures and the degree to which they increase feelings of safety. The results, together with summaries of similar studies, give an overview of passenger acceptance of various counter-terrorism security measures and point to areas for further research
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