124 research outputs found
Cryostatless high temperature supercurrent bearings for rocket engine turbopumps
The rocket engine systems examined include SSME, ALS, and CTV systems. The liquid hydrogen turbopumps in the SSME and ALS vehicle systems are identified as potentially attractive candidates for development of Supercurrent Bearings since the temperatures around the bearings is about 30 K, which is considerably lower than the 95 K transition temperatures of HTS materials. At these temperatures, the current HTS materials are shown to be capable of developing significantly higher current densities. This higher current density capability makes the development of supercurrent bearings for rocket engines an attractive proposition. These supercurrent bearings are also shown to offer significant advantages over conventional bearings used in rocket engines. They can increase the life and reliability over rolling element bearings because of noncontact operation. They offer lower power loss over conventional fluid film bearings. Compared to conventional magnetic bearings, they can reduce the weight of controllers significantly, and require lower power because of the use of persistent currents. In addition, four technology areas that require further attention have been identified. These are: Supercurrent Bearing Conceptual Design Verification; HTS Magnet Fabrication and Testing; Cryosensors and Controller Development; and Rocket Engine Environmental Compatibility Testing
Reduction in bearing size due to superconductors in magnetic bearings
A design concept that reduces the size of magnetic bearings is assessed. The small size will enable magnetic bearings to fit into limited available bearing volume of cryogenic machinery. The design concept, called SUPERC, uses (high Tc) superconductors or high-purity aluminum conductors in windings instead of copper. The relatively high-current density of these conductors reduces the slot radial thickness for windings, which reduces the size of the bearings. MTI developed a sizing program called SUPERC that translates the high-current density of these conductors into smaller sized bearings. This program was used to size a superconducting bearing to carry a 500 lb. load. The sizes of magnetic bearings needed by various design concepts are as follows: SUPERC design concept = 3.75 in.; magnet-bias design concept = 5.25 in.; and all electromagnet design concept = 7.0 in. These results indicate that the SUPERC design concept can significantly reduce the size of the bearing. This reduction, in turn, reduces the weight and yields a lighter bearing. Since the superconductors have inherently near-zero resistance, they are also expected to save power needed for operation considerably
Blueberry Progress Reports
The 1982 edition of the Blueberry Progress Reports was prepared for the Maine Blueberry Commission and the University of Maine Blueberry Advisory Committee by researchers with the Maine Life Sciences and Agriculture Experiment Station and Maine Cooperative Extension Service at the University of Maine, Orono. Projects in this report include:
1. Introduction
2. Blueberry IPM Program
3. Guthion Drift Study
4. Control, Biology, and Ecology of Insects
5. Blueberry Diseases: Incidence and Control
6. Physiology and Culture of the Lowbush Blueberry
7. Weed Control in Lowbush Blueberries
8. Pruning Blueberrie
Measuring attitudes, behaviours, and influences in inner city victims of interpersonal violence (VIVs) - a Swiss emergency room pilot study
Background
Switzerland is confronted with the problem of interpersonal violence. Violence is in the increase and the potential for aggression seems to be rising. Observations by hospitals discern an appalling increase of the severity of the injuries. The aim of this study is to collect accurate information about the social environment, the motivation and possible reasons for violence. We also intend to investigate whether sociocultural, or ethnic differences among male victims exist.
Materials and methods
For the first time in Switzerland, this survey employed a validated questionnaire from the division of violence prevention, Atlanta, Georgia. The first part of the questionnaire addressed social and demographic factors which could influence the risk of violence: age, gender, duration of stay in Switzerland, nationality and educational level. Beside these social structural factors, the questionnaire included questions on experience of violent offences in the past, information about the most recent violent offence and intra and interpersonal facts. The questionnaire itself consists of 27 questions, translated into German and French. In a pilot study, the questionnaire was checked with adolescents for feasibility and comprehensibility.
Results
69 male VIVs were interviewed at two hospitals in the Canton of Bern. Most of the adolescents emphasised that weapons were not used during their confrontations. It is astonishing that all of the young men considered themselves to be victims. Most of the brawls were incited after an exchange of verbal abuse and provocations with unfamiliar individuals. The rivals could neither be classified with the help of ethnic categories nor identifiable groups of the youth scenes. The incidents took place in scenes, where violence was more likely to happen. Interestingly and contrary to a general perception the offenders are well integrated into sport and leisure clubs. A further surprising result of our research is that the attitude towards religion differs between young men with experience of violence and non-violent men.
Discussion
Youth violence is a health issue, which concerns us globally. The human and economic toll of violence on victims and offenders, their families, and on society in general is high. The economic costs associated with violence-related illness and disability is estimated to be millions of Swiss francs each year. Physicians and psychologists are compelled to identify the factors, which cause young people to be violent, to find out which interventions prove to be successful, and to design effective prevention programs. The identification of effective programs depends on the availability of reliable and valid measures to assess changes in violence-related attitudes. In our efforts to create healthier communities, we need to investigate; document and do research on the causes and circumstances of youth violence
Blueberry Progress Reports
The 1983 edition of the Blueberry Progress Reports was prepared for the Maine Blueberry Commission and the University of Maine Blueberry Advisory Committee by researchers with the Maine Agricultural Experiment Station and Maine Cooperative Extension Service at the University of Maine, Orono. Projects in this report include:
1. Introduction
2. Forest Tent Caterpillar in Blueberries
3. Control, Biology, and Ecology of Insects Affecting Lowbush Blueberries
4. Blueberry Diseases: Incidence and Control
5. Physiology and Culture of the Lowbush Blueberry
6. Weed Control in Lowbush Blueberry Fields
7. Product Development of Lowbush Blueberrie
Explorations, Vol. 5, No. 1
Articles include:
Cover: What Have We Done with Tomorrow? by Leslie C. Hyde, UMCES Extension Agent for Knox-Lincoln Counties.
Editorial Reflections, Carole J. Bombard
UMCES: an overview
Conversation with the Director: Assistant Vice-President Judith Bailey
Reaching Out for Teen Awareness, by Theresa M. Ferrari
Profile of a Harbormaster, by Carole J. Bombard
Minding Maine’s Business, by Mary S. Bowie
Family Resource Management: Learning to ease the burden, by Olive Dubord and Doris Cushman
Breaking Free and Taking Control: Helen Sawyer’s Story, by Doris Manley
Partnership in Conservation: The Josephine Newman Sanctuary, by Nancy Coverstone
The Mount Desert Island Health Promotion Project, by Ron Beard
Dynamics of Weed Control in Agriculture, by Leigh Morrow
From Generation to Generation: An Extension Homemaker Family, by Nadine B. Reimer
ICLAD: The Institute for Community Leadership and Development, by Jim Killacky and Deb Burwell
Exploding the Cinderella Syndrome: Strengthening Stepfamilies, by Wendy Pollock
Integrated Pest Management: Bringing it all together, by Glen Koehler and Jim Dill
Addressing the Issues, by Patricia M. Pierson
Anti-Bruise: What’s It All About? Maine Potato Harvest Anti-Bruise Program, by Neal D. Hallee
H.O.P.E. Addresses Teenage Pregnancy, by Jane M. Kelly
Saving Money and the Environment, by Vaughn H. Holyoke
Reservoir Tillage in Nonirrigated Potato Production, by Leigh Morrow
Managing Pesticide Drift, by James D. Dwyer, Leigh S. Morrow and James F. Dill
The St. George River Project — what have we done with tomorrow?
Putting Research to Work, by Stephen Belyea
The Best Maine Blue: Fresh Pack Blueberries, by Tom DeGomez
Maine’s Green Sea Urchin, by Benjamin A. Baxter
Interfaces and Cooperation: Wildlife and Fisheries Sampler, by Catherine A. Elliott
Extension Responds to the Salmonella Scare, by Nellie Hedstrom and Mahmoud El-Begearm
The effect of prior walking on coronary heart disease risk markers in South Asian and European men.
Purpose: Heart disease risk is elevated in South Asians possibly due to impaired postprandial metabolism. Running has been shown to induce greater reductions in postprandial lipaemia in South Asian than European men but the effect of walking in South Asians is unknown. Methods: Fifteen South Asian and 14 White European men aged 19-30 years completed two, 2-d trials in a randomised crossover design. On day 1, participants rested (control) or walked for 60 min at approximately 50% maximum oxygen uptake (exercise). On day 2, participants rested and consumed two high fat meals over a 9h period during which 14 venous blood samples were collected. Results: South Asians exhibited higher postprandial triacylglycerol (geometric mean (95% confidence interval) 2.29(1.82 to 2.89) vs. 1.54(1.21 to 1.96) mmol·L-1·hr-1), glucose (5.49(5.21 to 5.79) vs. 5.05(4.78 to 5.33) mmol·L-1·hr-1), insulin (32.9(25.7 to 42.1) vs. 18.3(14.2 to 23.7) µU·mL-1·hr-1) and interleukin-6 (2.44(1.61 to 3.67) vs. 1.04(0.68 to 1.59) pg·mL-1·hr-1) than Europeans (all ES ≥ 0.72, P≤0.03). Between-group differences in triacylglycerol, glucose and insulin were not significant after controlling for age and percentage body fat. Walking reduced postprandial triacylglycerol (1.79(1.52 to 2.12) vs. 1.97(1.67 to 2.33) mmol·L-1·hr-1) and insulin (21.0(17.0 to 26.0) vs. 28.7(23.2 to 35.4) µU·mL-1·hr-1) (all ES ≥ 0.23. P≤0.01), but group differences were not significant. Conclusions: Healthy South Asians exhibited impaired postprandial metabolism compared with White Europeans, but these differences were diminished after controlling for potential confounders. The small-moderate reduction in postprandial triacylglycerol and insulin after brisk walking was not different between the ethnicities
Solution Structure and Dynamics of the I214V Mutant of the Rabbit Prion Protein
Background: The conformational conversion of the host-derived cellular prion protein (PrP C) into the disease-associated scrapie isoform (PrP Sc) is responsible for the pathogenesis of transmissible spongiform encephalopathies (TSEs). Various single-point mutations in PrP C s could cause structural changes and thereby distinctly influence the conformational conversion. Elucidation of the differences between the wild-type rabbit PrP C (RaPrP C) and various mutants would be of great help to understand the ability of RaPrP C to be resistant to TSE agents. Methodology/Principal Findings: We determined the solution structure of the I214V mutant of RaPrP C (91–228) and detected the backbone dynamics of its structured C-terminal domain (121–228). The I214V mutant displays a visible shift of surface charge distribution that may have a potential effect on the binding specificity and affinity with other chaperones. The number of hydrogen bonds declines dramatically. Urea-induced transition experiments reveal an obvious decrease in the conformational stability. Furthermore, the NMR dynamics analysis discloses a significant increase in the backbone flexibility on the pico- to nanosecond time scale, indicative of lower energy barrier for structural rearrangement. Conclusions/Significance: Our results suggest that both the surface charge distribution and the intrinsic backbone flexibility greatly contribute to species barriers for the transmission of TSEs, and thereby provide valuable hints fo
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