5,048 research outputs found
Improvement of chemical vapor deposition process for production of large diameter carbon base monofilaments
Research was conducted to develop large diameter carbon monofilament, containing 25 to 35 mole % element boron, in the 2.0 to 10.0 mil diameter range using the chemical vapor deposition process. The objective of the program was to gain an understanding of the critical process variables and their effect on fiber properties. Synthesis equipment was modified to allow these variables to be studied. Improved control of synthesis variables permitted reduction in scatter of properties of the monofilaments. Monofilaments have been synthesized in the 3.0 to nearly 6.0 mil diameter range having measured values up to 552,000 psi for ultimate tensile strength and up to 30 million psi for elastic modulus
Further development of chemical vapor deposition process for production of large diameter carbon-base monofilaments
The development of large diameter carbon-base monofilament in the 50 micron to 250 micron diameter range using the chemical vapor deposition process is described. The object of this program was to determine the critical process variables which control monofilament strength, monofilament modulus, and monofilament diameter. It was confirmed that wide scatter in the carbon substrate strength is primarily responsible for the scatter in the monofilament strength. It was also shown through etching experiments that defective substrate surface conditions which can induce low strength modular growth in the monofilament layers are best controlled by processing improvements during the synthesis of the substrate. Modulus was found to be linearily proportional to monofilament boron content. Filament modulus was increased to above 27.8MN/sq cm but only by a considerable increase in monofilament boron content to 60 wt. % or more. Monofilament diameter depended upon dwell time in the synthesis apparatus. A monofilament was prepared using these findings which had the combined properties of a mean U.T.S. of 398,000 N/sq cm, a modulus of 18.9 MN/sq cm (24,000,000 psi), and a diameter of 145 microns. Highest measured strength for this fiber was 451,000 N/sq cm (645,000 psi)
Improving stress coping ability: comparison between the CYP17 genotype Of Ovis Aries and Capra Hircus
The ability of animals to adapt to stress is not only an animal health and welfare concern, but also influences reproduction potential and robustness. An important pathway involved in the stress response is the hypothalamic-pituitary-adrenal axis (HPAA) that results in the release of cortisol from the adrenal gland. In this study the cortisol responses of South African Merinos were measured to assess HPAA responsiveness to stress and relate it to behavioural stress responses to
flock-isolation. The experiment was structured according to a 2×2 statistical design, with CYP17 genotype (WT1/WT1 vs. WT1/WT2) and selection line (H-line vs. L-line) as factors. Selection line criteria was based on divergent selection for (H-line) or against (L-line) maternal multiple rearing ability, where the H-line generally outperformed the L-line in terms of reproduction, animal
welfare and resistance to certain pathogens. The CYP17 genotype is involved in the biosynthesis pathway of cortisol. In the present study the CYP17 genotype showed a significant influence on behavioural stress responses, where three parameters of the flock-isolation test were affected (P<0.05), namely the number of bleats uttered, the urinating frequency and the average distance from a human operator. It is suggested that the CYP17 genotype affects behavioural responses via its effects on cortisol production, and that the SNPs located within the CYP17 genotype may have application in marker-assisted selection of sheep
Researching trust in the police and trust in justice: a UK perspective
This paper describes the immediate and more distant origins of a programme of comparative research that is examining cross-national variations in public trust in justice and in the police. The programme is built around a module of the fifth European Social Survey, and evolved from a study funded by the European Commission. The paper describes the conceptual framework within which we are operating – developed in large measure from theories of procedural justice. It reviews some of the methodological issues raised by the use of sample surveys to research issues of public trust in the police, public perceptions of institutional legitimacy and compliance with the law. Finally it gives a flavour of some of the early findings emerging from the programme
LANGUAGE OUTCOMES IN SCHOOL-AGED CHILDREN ADOPTED FROM EASTERN EUROPEAN ORPHANAGES
Developmental studies by pediatricians and surveys of adoptive parents of children that have been adopted to the United States from foreign countries indicate that many of these children are experiencing substantial difficulties with the acquisition of their new language. Language difficulties may compromise the adopted child's abilities to understand, negotiate, and adjust to a new family and environment (Jenista, 1993). Reports range from 100% of the children having difficulties (Willig, 1995) to 34% (Groza,1995), with the majority of researchers reporting incidences in the 30-50% range (Johnson et al. 1996; Hough, 1996). These figures are in-line with research from countries such as Norway (Dalen, 2001a; Saetersdal & Dalen, 1987), Denmark (Rorbech, 1997) and Holland (Hoksbergen, 1997). To date, no studies directly assessing the language skills, long-term outcomes, or the types of language difficulties experienced by these children after experiencing an abrupt language switch have been completed. This study evaluated the language skills of a group of 44 school-aged, post-institutionalized Eastern European adoptees (EEA-PI) to determine the extent, and the types, of problems present in the areas of semantics, morphology, syntax, pragmatics, and reading, and explored the factors of institutionalization that might predict language development. Results showed that as a group, EEA-PI children, in comparison to the normative data on the standardized and spontaneous speech measures, performed lower than age expectations on all of the measures, with the exception of measures of listening (receptive language). The disparity within the group's performance was notable. Though institutional factors of time in institution, age of adoption, and time in U.S. did not correlate with measures of receptive and expressive language, they were significant for reading and nonword repetition scores. This research furthers our professional knowledge regarding long-term language outcomes and the selection of appropriate diagnostic measures for these children and other children experiencing early neglect in our country
Wide parameter search for isolated pulsars using the Hough transform
We use the Hough transform to analyze data from the second science run of the
LIGO interferometers, to look for gravitational waves from isolated pulsars. We
search over the whole sky and over a large range of frequencies and spin-down
parameters. Our search method is based on the Hough transform, which is a
semi-coherent, computationally efficient, and robust pattern recognition
technique. We also present a validation of the search pipeline using hardware
signal injections.Comment: Presented at GWDAW-9 in Annecy, France (Dec. 2004). 11 pages, 5
Figures. To appear in Classical and Quantum Gravit
RELATIVE ABUNDANCE OF NORTHERN FLYING SQUIRRELS AND RED SQUIRRELS IN DIFFERENT FOREST TYPES, BLACK HILLS, SOUTH DAKOTA
Northern flying squirrels (Glaucomys sabrinus) and red squirrels (Tamiasciurus hudsonicus) in the Black Hills National Forest (BHNF) of South Dakota represent isolated populations. Because data on both species in the region are limited, and because the northern flying squirrel in South Dakota and the Black Hills National Forest has species of concern status, we trapped throughout BHNF to determine relative abundance in different forest types for both populations. For northern flying squirrels, capture rate was higher in the northern and western hills compared to the southern and eastern hills, whereas for red squirrels, capture rate was higher in the western hills, followed by the southern and eastern hills. The northern hills are classified as mesic coniferous forest transitioning to a dry coniferous forest in the southern hills. In addition, the northern hills is characterized by a mixed coniferous-deciduous forest, whereas the southern and eastern hills are characterized by even-aged managed coniferous stands. Understanding the abundance of these two isolated squirrel populations in the different forest types of the BHNF is important in intensively managed forests, because management decisions can impact isolated populations
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