5,458 research outputs found
Study of outgassing and decomposition of space shuttle heat protection tiles, fillers and adhesive
The purpose of this project was to determine the chemicals desorbing from the space shuttle heat protection tiles. The original protocol for this project involved direct insertion probe mass spectrometry (DIPMS) analysis of the outgassing products from the tiles. However, this method proved unsatisfactory due to the large number of compounds desorbing from the tiles. A purge and trap technique was then employed to collect and separate the chemicals desorbing from the tiles. The maximum temperature in this analysis was 180 C which is the gas chromatograph fused silica capillary column's temperature limit. The desorption was also carried out at atmospheric pressure with helium as the purge gas. A description of the modified protocol is given. All compounds are tentatively identified
Effect of nutritional deficiency on ruffed grouse condition and reproductive success
Maternal body fat condition (i.e., percent carcass fat) is often a focal point in determining reproductive success in female galliforms. Previous research has centered around habitat-related nutritional parameters affecting body condition and the influence on reproductive capacity. Past studies have shown that ruffed grouse (Bonasa umbellus) maintain higher mean body fat levels throughout the Appalachians and variation in body condition exceeds that found in northern grouse. In the Appalachians, ruffed grouse with diets devoid of energy-rich hard mast have lower body fat condition. It has been hypothesized that females in poorer condition will have lower productivity in the Appalachians. We conducted a 2-year study of captive Appalachian ruffed grouse (subspecies Bonasa umbellus monticola) to assess the effects of 4 treatment rations varying in dietary energy and crude protein on female body condition throughout the pre-breeding and reproduction periods using total body electrical conductivity (TOBEC) technology. Females on low protein rations maintained higher carcass fat levels than females on high protein treatments, although high protein treatments led to less fat loss during reproduction. High-energy rations produced females with higher fat levels prior to reproduction; however, adult females on high-energy treatments lost more fat during reproduction than low-energy treatments. We posit that the presence of low-protein, high-energy feed items in diets of Appalachian ruffed grouse potentially lead to higher percent body fat, whereas high-protein diets support leaner grouse. We also determined the effect of body fat condition on onset of laying, egg quality, clutch size, and chick mass at hatch. Our experimental treatment rations stratified females into differing fat condition classes, ranging from 3.9--43.5% body fat. Although egg composition differed among condition classes, we found no evidence of a relation between fat condition and egg composition. Female grouse were capable of producing comparable eggs, clutches, and chicks across varying planes of body fat condition. Our results suggest that the effect of increased fat reserves in Appalachian ruffed grouse does not directly influence fecundity. We propose that any influence female condition has on fecundity and chick survival is enacted after the nesting effort is complete
Neural regulation of the protein composition of saliva
Fluid and protein secretion from salivary glands are primarily regulated by efferent parasympathetic and sympathetic nerves respectively. The protein concentration of saliva, which is made up of a number of functionally important proteins, can vary depending on the impulse traffic arriving from these nerves. The composition of the proteins secreted by a salivary gland with a mixed population of secretory cells can vary with different secretory stimuli and intensities of stimuli, according to how the individual cell populations respond. Most of the published evidence suggests that the protein composition of saliva secreted form the parotid gland, which has an apparently homogeneous secretory cell population, appears to be similar regardless of the type of nerve stimulus. It is likely that salivary secretory cells can secrete protein by a constitutive route, not involving storage granules, in addition to the regulated secretion of protein from storage granules, and that the constitutive route may operate during parasympathetic nerve stimulation. However the functional significance of this type of protein secretion is as yet unknown. In the longer-term the composition of proteins secreted from salivary glands also depends upon the rates of synthesis of individual proteins. Levels of secretory proteins show differing dependencies on specific nerve-mediated stimuli as shown by the changing compositions of proteins secreted following denervation or chronic pharmacological blockade. The levels of secreted proteins appear to be regulated at both the transcriptional and translational levels of protein synthesis. In rodent salivary glands there is a dependency of secretory proline-rich protein synthesis on β-adrenergically mediated stimuli which is dependent upon putative cAMP regulatory sequences of nucleotides in the gene. Although N-linked glycosylation has been shown to be regulated by β-adrenergically mediated stimuli, it is not known if the composition of sugars on proteins varies with neural stimuli.Biomedical Reviews 1993; 2: 47-56
Crew appliance concepts. Volume 4, appendix C: Modular space station appliances supporting engineering data
Data collected for the appliances considered for the space station are presented along with plotted and tabulated trade study results for each appliance. The food management, and personal hygiene data are applicable to a six-man mission of 180-days
Study of outgassing and decomposition of Space Shuttle heat protection tiles, fillers and adhesive
A purge and trap technique which was employed to collect and separate the chemicals desorbing from the space shuttle heat protection tiles is described. The instrumentation included a mass spectrometer and gas chromatograph
Crew appliance concepts. Volume 2, appendix B: Shuttle orbiter appliances supporting engineering data
Technical data collected for the food management and personal hygiene appliances considered for the shuttle orbiter are presented as well as plotted and tabulated trade study results for each appliance. Food storage, food operation, galley cleanup, waste collection/transfer, body cleansing, and personal grooming were analyzed
Crew appliance study
Viable crew appliance concepts were identified by means of a thorough literature search. Studies were made of the food management, personal hygiene, housekeeping, and off-duty habitability functions to determine which concepts best satisfy the Space Shuttle Orbiter and Modular Space Station mission requirements. Models of selected appliance concepts not currently included in the generalized environmental-thermal control and life support systems computer program were developed and validated. Development plans of selected concepts were generated for future reference. A shuttle freezer conceptual design was developed and a test support activity was provided for regenerative environmental control life support subsystems
Langley Research Center Strategic Plan for Education
Research assignment centered on the preparation of final draft of the NASA Langley Strategic Plan for Education. Primary research activity consisted of data collection, through interviews with LaRC Office of Education and NASA Headquarters staff, university administrators and faculty, and school administrators / teachers; and documentary analysis. Pre-college and university programs were critically reviewed to assure effectiveness, support of NASA and Langley's mission and goals; National Education Goals; and educational reform strategies. In addition to these mandates, pre-college programs were reviewed to address present and future LaRC activities for teacher enhancement and preparation. University programs were reviewed with emphasis on student support and recruitment; faculty development and enhancement; and LaRC's role in promoting the utilization of educational technologies and distance learning. The LaRC Strategic Plan for Education will enable the Office of Education to provide a focused and well planned continuum of education programs for students, teachers and faculty. It will serve to direct and focus present activities and programs while simultaneously offering the flexibility to address new and emerging directions based on changing national, state, and agency trends
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