2,927 research outputs found

    Wall-temperature effects on the aerodynamics of a hydrogen-fueled transport concept in Mach 8 blowdown and shock tunnels

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    Results are presented from two separate tests on the same blended wing-body hydrogen fueled transport model at a Mach number of about 8 and a range of Reynolds numbers (based on theoretical body length) of 0.597 x 10 to the 6th power to about 156.22 x 10 to the 6th power. Tests were made in conventional hypersonic blowdown tunnel and a hypersonic shock tunnel at angles of attack of -2 deg to about 8 deg, with an extensive study made at a constant angle of attack of 3 deg. The model boundary-layer flow varied from laminar at the lower Reynolds numbers to predominantly turbulent at the higher Reynolds numbers. Model wall temperatures and stream static temperatures varied widely between the two tests, particularly at the lower Reynolds numbers. These temperature differences resulted in marked variations of the axial-force coefficients between the two tests, due in part to the effects of induced pressure and viscous interaction variations. The normal-force coefficient was essentially independent of Reynolds number. Analysis of results utilized current theoretical computer programs and basic boundary-layer theory

    Large Loops of Magnetic Current and Confinement in Four Dimensional U(1)U(1) Lattice Gauge Theory

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    We calculate the heavy quark potential from the magnetic current due to monopoles in four dimensional U(1)U(1) lattice gauge theory. The magnetic current is found from link angle configurations using the DeGrand-Toussaint identification method. The link angle configurations are generated in a cosine action simulation on a 24424^4 lattice. The magnetic current is resolved into large loops which wrap around the lattice and simple loops which do not. Wrapping loops are found only in the confined phase. It is shown that the long range part of the heavy quark potential, in particular the string tension, can be calculated solely from the large, wrapping loops of magnetic current.Comment: 15 pages (Latex file plus 3 postscript files appended), Univeristy of Illinois Preprint ILL-(TH)-93-\#1

    Some remarks on particle size effects on the abrasion of a range of Fe based alloys

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    The low-stress three body abrasion behaviour of a range of steels was investigated. The tests were carried out in a rubber wheel tester (according to ASTM G65-94, reapproved in 2000) at room temperature. The abrasive particles used were angular alumina particles of four different sizes. The results showed that, in general, the smaller particles (50 8m and 125 8m average size) caused more damage. With these particles, observations of surface morphology indicarted a more intense cutting and ploughing action, leading to more damage, whereas bigger particles i.e. larger 250 8m and 560 8m particles produced less damage, and their action involved more plastic deformation type wear. The 304 SS had a lower abrasion resistance than the 310 SS. For the austentic and ferritic steels the subsurface deformation was larger for impact with the coarser particles. Variations in substrate hardness had no effect on the abrasive behaviour observed. On the whole, the hardest steel (mild steel in martensitic condition) showed the higher extent of damage, irrespective of particle size

    String Tension from Monopoles in SU(2) Lattice Gauge Theory

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    The axis for Figure 2 was wrong. It has been fixed and the postscript file replaced (The file was called comp.ps).Comment: (22 pages latex (revtex); 2 figures appended as postscript files - search for mono.ps and comp.ps. Figures mailed on request--send a note to [email protected]) Preprint ILL-(TH)-94-#1

    The Attitudes about Complex Therapy Scale (ACTS) in Type 2 Diabetes and Cardiovascular Disease: Development, Validity and Reliability

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    Background: Type 2 diabetes is associated with cardiovascular disease, and patients with both conditions are prescribed complex medication regimens. Aim: The aim was to develop a reliable and valid measure of attitudes associated with the prescription and management of multiple medicines in patients with Type 2 diabetes and cardiovascular disease. Methods: Principal component analysis (PCA) and Cronbach alpha assessed the reliability of the Attitudes about Complex Therapy Scale (ACTS). Examinations of relationships with related measures inform concurrent validity. Questionnaires were sent to a cross-sectional sample of 480 people prescribed multiple medicines for co-morbid Type 2 diabetes. Results: Cronbach alpha was 0.76, indicating the scale had good internal reliability. PCA rotated a four factor model accounting for 37% of the variance. Four subscales identified; 1. Concerns about multiple medicines and increasing numbers of medicines; 2.Anxiety over missed medicines; 3. Desires to substitute medicines and reduce the number of medicines prescribed and; 4. Perceptions related to organising and managing complex therapy. The ACTS showed significant relationships with measures of anxiety, depression, general beliefs about medicines and self-efficacy. Also, the ACTS significantly correlated with adherence to medicines, showing good predictive validity. Conclusion: The ACTS was designed to assess negative attitudes towards complex therapy and multiple medication management. This tool could aid prescribing decisions and may identify people who are intentionally non-adherent to all or some of their medicines

    Gribov Copies in the Maximally Abelian Gauge and Confinement

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    We fix SU(2)SU(2) lattice gauge fields to the Maximally Abelian gauge in both three and four dimensions. We extract the corresponding U(1)U(1) fields and monopole current densities and calculate separately the confining string tensions arising from these U(1)U(1) fields and monopole `condensates'. We generate multiple Gribov copies and study how the U(1)U(1) fields and monopole distributions vary between these different copies. As expected, we find substantial variations in the number of monopoles, their locations and in the values of the U(1)U(1) field strengths. The string tensions extracted from `extreme' Gribov copies also differ but this difference appears to be no more than about 20\%. We also directly compare the fields of different Gribov copies. We find that on the distance scales relevant to confinement the U(1)U(1) and monopole fluxes that disorder Wilson loops are highly correlated between these different Gribov copies. All this suggests that while there is indeed a Gribov copy problem the resulting ambiguity is, in this gauge and for the study of confinement, of limited importance.Comment: 31 pages LaTeX plus 5 PostScript figures. Uses epsf.sty. Self-unpacking, uuencoded tar-compressed fil

    Experiences of South Asian patients in early inflammatory arthritis clinic: a qualitative interview study

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    Objective: The aim was to explore how UK South Asian patients living with RA interact with health care professionals and experience receiving health information in an early inflammatory arthritis clinic. Methods: A semi-structured interview schedule, designed in conjunction with a patient partner, was used for face-to-face interviews. South Asian participants with RA were recruited from Central Manchester University Hospitals National Health Service Foundation Trust. Data were recorded and transcribed by an independent company. Data were analysed using inductive thematic analysis. Results: Fifteen participants were interviewed. Three predominant themes emerged around participants’ experiences and interaction with health care professionals in early inflammatory arthritis clinic. First, ‘the personal experiences of RA and cultural link to early inflammatory arthritis clinic’, where participants described the impact of RA as individuals and their altered roles within their cultural setting. Second, ‘experiences of interacting and receiving information in the early inflammatory arthritis clinic’, where participants described their limited engagement with health care professionals and the quality of information discussed in the clinic. Third, ‘views on future content for early inflammatory arthritis clinics’, where participants highlighted new innovative ideas to build on current practice. Conclusion: We believe this to be the first study to generate insight into the experiences of South Asian patients of interacting with health care professionals while attending an early inflammatory arthritis clinic. Policy directives aimed at improving access to services and delivery of information for ethnic minority groups in early inflammatory arthritis clinics should include consideration of the different roles of cultures. Professionals should be cognizant of the factors that drive health inequalities and focus on improving service delivery

    Intake and Milk Production of Lactating Dairy Cows Grazing Diverse Forage Mixtures Over Two Grazing Seasons

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    Voluntary intake and stocking rate are key determinants of animal performance on pasture. Greater plant diversity in grassland plant communities has been linked to increased primary production, greater stability in response to disturbance, and reduced weed pressure. Thus, increasing plant diversity may be one approach to improving animal productivity. An experiment was conducted to determine the effects of forage diversity on intake and milk production of lactating dairy cows over two grazing seasons

    Moving beyond the ‘language problem': developing an understanding of the intersections of health, language and immigration status in interpreter-mediated health encounters

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    Health systems internationally are dealing with greater diversity in patient populations. However the focus on ‘the language problem’ has meant little attention is paid to diversity within and between migrant populations; and how interpreted consultations are influenced by intersecting migratory, ethnicity and sociodemographic variables. Our analysis of the experiences of patients, health care providers and interpreters in Scotland evidences the need to move beyond language, addressing multiple hidden inequalities in health care access and provision that operate in both clinic and, especially, home-based settings. We call for a practice-evidenced research agenda promoting cultural communication across health care and home settings, acknowledging immigration status as a social determinant of health. Sur le plan international, des systèmes de santé font face à une diversité croissante dans ses populations de patients. Cependant, l’accent sur ‘le problème de langue’ se traduit dans une manque d’attention à la diversité a l’intérieur même et entre des populations des migrants; et la façon par laquelle des variables migratoire, ethnique et sociodémographique influencent elles-mêmes des consultations interprétées. Notre analyse des expériences des patients, des professionnels fournissant de soins de santé et des interprètes offre des preuves du besoin de dépasser le problème de langue. Et en faisant cela, nous adressons des multiples inégalités, souvent cachées dans des contextes de soins de santé, dans les milieux clinique et domicile. Nous proposons un programme de recherche basé sur la pratique, qui favorise la communication culturelle dans des milieux clinique et domicile, et qui reconnait le statut d’immigration comme un déterminant social de la santé

    The Coulomb law in the pure gauge U(1) theory on a lattice

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    We study the heavy charge potential in the Coulomb phase of pure gauge compact U(1) theory on the lattice. We calculate the static potential VW(T,R⃗)V_W(T,{\vec R}) from Wilson loops on a 163×3216^3 \times 32 lattice and compare with the predictions of lattice perturbation theory. We investigate finite size effects and, in particular, the importance of non-Coulomb contributions to the potential. We also comment on the existence of a maximal coupling in the Coulomb phase of pure gauge U(1) theory.Comment: 14 pages. LaTeX file and 3 postscript figure
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