16,027 research outputs found
Forced-flow once-through boilers
A compilation and review of NASA-sponsored research on boilers for use in spacecraft electrical power generation systems is presented. Emphasis is on the heat-transfer and fluid-flow problems. In addition to space applications, much of the boiler technology is applicable to terrestrial and marine uses such as vehicular power, electrical power generation, vapor generation, and heating and cooling. Related research areas are discussed such as condensation, cavitation, line and boiler dynamics, the SNAP-8 project (Mercury-Rankine cycle), and conventional terrestrial boilers (either supercritical or gravity-assisted liquid-vapor separation types). The research effort was directed at developing the technology for once-through compact boilers with high heat fluxes to generate dry vapor stably, without utilizing gravity for phase separations. A background section that discusses, tutorially, the complex aspects of the boiling process is presented. Discussions of tests on alkali metals are interspersed with those on water and other fluids on a phenomenological basis
Bound state structure and electromagnetic form factor beyond the ladder approximation
We investigate the response of the bound state structure of a two-boson
system, within a Yukawa model with a scalar boson exchange, to the inclusion of
the cross-ladder contribution to the ladder kernel of the Bethe-Salpeter
equation. The equation is solved by means of the Nakanishi integral
representation and light-front projection. The valence light-front wave
function and the elastic electromagnetic form factor beyond the impulse
approximation, with the inclusion of the two-body current, generated by the
cross-ladder kernel, are computed. The valence wave function and
electromagnetic form factor, considering both ladder and ladder plus
cross-ladder kernels, are studied in detail. Their asymptotic forms are found
to be quite independent of the inclusion of the cross-ladder kernel, for a
given binding energy. The asymptotic decrease of form factor agrees with the
counting rules. This analysis can be generalized to fermionic systems, with a
wide application in the study of the meson structure.Comment: 19 pages, 6 figures, submitted to Phys. Lett.
Bethe-Salpeter bound-state structure in Minkowski space
The quantitative investigation of the scalar Bethe-Salpeter equation in
Minkowski space, within the ladder-approximation framework, is extended to
include the excited states. This study has been carried out for an interacting
system composed by two massive bosons exchanging a massive scalar, by adopting
(i) the Nakanishi integral representation of the Bethe-Salpeter amplitude, and
(ii) the formally exact projection onto the null plane. Our analysis, on one
hand, confirms the reliability of the method already applied to the ground
state and, on the other one, extends the investigation from the valence
distribution in momentum space to the corresponding quantity in the
impact-parameter space, pointing out some relevant features, like (i) the
equivalence between Minkowski and Euclidean transverse-momentum amplitudes, and
(ii) the leading exponential fall-off of the valence wave function in the
impact-parameter space.Comment: 15 pages, 7 figure
Honey bee colony losses
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Female Rhesus Macaques (Macaca mulatta) Sexual Skin Color Variability
Many primate species use colorful signals to communicate sexual receptivity, rank, pregnancy, health, and developmental maturity. Reproductive coloration may not be limited to signaling sexual receptivity or pregnancy, but may also communicate aspects of female quality. Our preliminary study examined the relationships between female sexual skin coloration, mating status, and female traits, including age and dominance rank. The study took place at the Cayo Santiago (CS) facility in Puerto Rico; data were collected May through August of 2006. We examined two questions: 1) Is sexual skin coloration related to mating status?; and 2) Are inter-and intra-individual color differences related to female traits?
Facial coloration was not significantly related to mating status; genital saturation was significantly higher among mating females and among high-ranking females. Age was negatively correlated with both genital hue and genital saturation range; older females had more restricted coloration and younger females had more variable color. These preliminary results suggest that female coloration may reliably indicate aspects of female quality or condition to conspecifics, including potential mates
Nutritional, phytochemical and cytotoxicity analyses of air potato Dioscorea bulbifera L.bulbils
Air potato Dioscorea bulbifera L. is a crop that robustly grows and voluminously fruits but less utilized and adopted for consumption and cultivation. This investigation focused on the determination of the nutritional and phytochemical content and cytotoxicity of air potato D. Bulbifera L. bulbils from Nueva Vizcaya and Quirino. Analyses revealed that the bulbils contained moisture of 17.52-26.84%, ash of 0.737-7.28g/100g, lipids of 0.1593-0.2032g/100g, the crude fiber of 0.29-2.7942, the protein of 1.0 mg/ml, and total carbohydrates of 0.8189-0.8721g/100g sample. These primary metabolites are essential for plant growth, development, defense against diseases, and stress. These nutrients are vital for human nutrition and wellness as well. The presence of secondary metabolites such as anthraquinones, anthrones, coumarins, essential oils, fatty acids, flavonoids, phenols, steroids, triterpenes, and tannins were also revealed in the phytochemical screening. These secondary metabolites are distinct characteristics of plants which when properly extracted can be a source of materials for breakthroughs in food development, nutraceuticals, and pharmaceuticals. The bulbils were also found to be nontoxic. Thus, safe to be eaten. Geographical and environmental awareness, proper preparation and cooking management are must considerations to ensure its safety and economic value. With these capacities discovered, undeniably air potato is a cheap but rich source of material for food and medicine. These results are baseline data for bulbils found in the locality to be adopted to maximize the crop's produce for food processing, development, income generation, and cultivation
Sensory Characteristics and Acceptability of air potato Dioscorea bulbifera L. bulbils products
Air potato, Dioscorea bulbifera L., bulbils are known to contain primary metabolites such as ash, carbohydrates, crude fiber, lipid, moisture and protein. It also exhibited secondary metabolites: anthrones, anthraquinones, coumarins, essential oils, fatty acids, flavonoids, phenols, steroids, tannins and triterpenes. Cytotoxicity analyses also revealed its non-toxic nature and thus, safe to be consumed. These scientific data were the bases for developing products for maximum utilization of the crop for household consumption and additional income generation through cultivation. This study focused on the sensory characteristics and acceptability of the identified products of air potato (AP) bulbils for consumption and adoption by farmers. It used the descriptive research design. A researcher-made questionnaire was used as the instrument for gathering the data needed. The data were analyzed using the Hedonic scale, frequency count and mean. The findings showed that air potato halaya (jam) and ice cream were liked and accepted extremely; air potato polvoron and maja (white pudding) were liked and accepted very much; air potato chips and flour were liked and accepted moderately. Air potato flour, mainly the ingredient for polvoron and maja, was slightly liked and accepted due to its bitterness. These evaluations revealed that air potato bulbils when adequately nurtured and prepared can be a vital aid for family consumption, additional livelihood and a cheap rich nutritious source of raw materials. Thus, these significant results strongly recommend air potatoes for cultivation and promotion of the diversity and conservation of their species
Universal accessible closed captioning and sign language
Visual performances often include audio portions, including spoken words. The verbal content can be difficult to hear or otherwise understand for individuals that have hearing impairments or are not fluent in the language of the verbal content. This disclosure provides a solutions to make verbal content of visual performances accessible to audience members. The described assistive techniques utilize a smartphone to present to audience members, closed captions or American Sign Language (ASL) interpreters of the verbal content portion, simultaneously as the audience members view the performance. The translation can be presented as an overlay with a view of the performance (AR), as an overlay on a projected image of the performance, (VR), or on a display screen of the smartphone (side-channel)
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