5,362 research outputs found
Floating substrate process: Large-area silicon sheet task low-cost solar array project
Supercooling of silicon-tin alloy melts was studied. Values as high as 78 C at 1100 C and 39 C at 1200 C were observed, corresponding to supersaturation parameter values 0.025 and 0.053 at 1050 C and 1150 C, respectively. The interaction of tin with silane gas streams was investigated over the temperature range 1000 to 1200 C. Single-pass conversion efficiencies exceeding 30% were obtained. The growth habit of spontaneously-nucleated surface growth was determined to be consistent with dendritic and web growth from singly-twinned triangular nucleii. Surface growth of interlocking silicon crystals, thin enough to follow the surface of the liquid and with growth velocity as high as 5 mm/min, was obtained. Large area single-crystal growth along the melt surface was not achieved. Small single-crystal surface growth was obtained which did not propagate beyond a few millimeters
The Conformal Penrose Limit and the Resolution of the pp-curvature Singularities
We consider the exact solutions of the supergravity theories in various
dimensions in which the space-time has the form M_{d} x S^{D-d} where M_{d} is
an Einstein space admitting a conformal Killing vector and S^{D-d} is a sphere
of an appropriate dimension. We show that, if the cosmological constant of
M_{d} is negative and the conformal Killing vector is space-like, then such
solutions will have a conformal Penrose limit: M^{(0)}_{d} x S^{D-d} where
M^{(0)}_{d} is a generalized d-dimensional AdS plane wave. We study the
properties of the limiting solutions and find that M^{(0)}_{d} has 1/4
supersymmetry as well as a Virasoro symmetry. We also describe how the
pp-curvature singularity of M^{(0)}_{d} is resolved in the particular case of
the D6-branes of D=10 type IIA supergravity theory. This distinguished case
provides an interesting generalization of the plane waves in D=11 supergravity
theory and suggests a duality between the SU(2) gauged d=8 supergravity of
Salam and Sezgin on M^{(0)}_{8} and the d=7 ungauged supergravity theory on its
pp-wave boundary.Comment: 20 pages, LaTeX; typos corrected, journal versio
Child support reform: some analysis of the 1999 white paper
This paper uses a sample of lone mothers (and former lone mothers who are now repartnered) drawn from the 1997 Family Resources Survey to analyse the potential effects of reforming the UK system of Child Support. The main deficiency of the data is that non-resident fathers cannot be matched to the mothers in the data and this is overcome by exploiting information from another dataset which gives the joint distribution of the characteristics of separated parents. The effects of reforming the Child Support system is simulated for the amount of maintenance liabilities, the amount paid and the net incomes of households containing mothers with care and households containing non-resident fathers. The likely effects of the reform are simulated at various levels of compliance. The analysis highlights the need for further research into the incentive effects of Child Support on individual behaviour
Diagnosis and Decision-Making in Telemedicine
This article provides an analysis of the skills that health professionals and patients employ in reaching diagnosis and decision-making in telemedicine consultations. As governmental priorities continue to emphasize patient involvement in the management of their disease, there is an increasing need to accurately capture the providerâpatient interactions in clinical encounters. Drawing on conversation analysis of 10 video-mediated consultations in 3 National Health Service settings in England, this study examines the interaction between patients, General Practitioner (GPs), nurses, and consultants during diagnosis and decision-making, with the aim to identify the range of skills that participants use in the process and capture the interprofessional communication and patient involvement in the diagnosis and decision-making phases of telemedicine consultations. The analysis shows that teleconsultations enhance collaborative working among professionals and enable GPs and nurses to develop their skills and actively participate in diagnosis and decision-making by contributing primary careâspecific knowledge to the consultation. However, interprofessional interaction may result in limited patient involvement in decisionmaking. The findings of this study can be used to inform training programs in telemedicine that focus on the development of effective skills for professionals and the provision of information to patients
Size-Dependent Transition to High-Dimensional Chaotic Dynamics in a Two-Dimensional Excitable Medium
The spatiotemporal dynamics of an excitable medium with multiple spiral
defects is shown to vary smoothly with system size from short-lived transients
for small systems to extensive chaos for large systems. A comparison of the
Lyapunov dimension density with the average spiral defect density suggests an
average dimension per spiral defect varying between three and seven. We discuss
some implications of these results for experimental studies of excitable media.Comment: 5 pages, Latex, 4 figure
Fluctuations in the Site Disordered Traveling Salesman Problem
We extend a previous statistical mechanical treatment of the traveling
salesman problem by defining a discrete "site disordered'' problem in which
fluctuations about saddle points can be computed. The results clarify the basis
of our original treatment, and illuminate but do not resolve the difficulties
of taking the zero temperature limit to obtain minimal path lengths.Comment: 17 pages, 3 eps figures, revte
Isomorphism between Non-Riemannian gravity and Einstein-Proca-Weyl theories extended to a class of Scalar gravity theories
We extend the recently proved relation between certain models of
Non-Riemannian gravitation and Einstein- Proca-Weyl theories to a class of
Scalar gravity theories. This is used to present a Black-Hole Dilaton solution
with non-Riemannian connection.Comment: 13 pages, tex file, accepted in Class. Quant. Gra
A generalized Tullock contest
We construct a generalized Tullock contest under complete information where contingent upon winning or losing, the payoff of a player is a linear function of prizes, own effort, and the effort of the rival. This structure nests a number of existing contests in the literature and can be used to analyze new types of contests. We characterize the unique symmetric equilibrium and show that small parameter modifications may lead to substantially different types of contests and hence different equilibrium effort levels
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