7,817 research outputs found

    Coldplate of pin fin design makes efficient heat exchanger

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    Flat, hollow coldplate that permits the flow of coolant liquid removes heat from heat-generating electronic equipment. This coldplate solves usual problems of bulk, weight, and excessive pumping requirements

    Neutron detector simultaneously measures fluence and dose equivalent

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    Neutron detector acts as both an area monitoring instrument and a criticality dosimeter by simultaneously measuring dose equivalent and fluence. The fluence is determined by activation of six foils one inch below the surface of the moderator. Dose equivalent is determined from activation of three interlocked foils at the center of the moderator

    Spatial Mixing of Coloring Random Graphs

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    We study the strong spatial mixing (decay of correlation) property of proper qq-colorings of random graph G(n,d/n)G(n, d/n) with a fixed dd. The strong spatial mixing of coloring and related models have been extensively studied on graphs with bounded maximum degree. However, for typical classes of graphs with bounded average degree, such as G(n,d/n)G(n, d/n), an easy counterexample shows that colorings do not exhibit strong spatial mixing with high probability. Nevertheless, we show that for qαd+βq\ge\alpha d+\beta with α>2\alpha>2 and sufficiently large β=O(1)\beta=O(1), with high probability proper qq-colorings of random graph G(n,d/n)G(n, d/n) exhibit strong spatial mixing with respect to an arbitrarily fixed vertex. This is the first strong spatial mixing result for colorings of graphs with unbounded maximum degree. Our analysis of strong spatial mixing establishes a block-wise correlation decay instead of the standard point-wise decay, which may be of interest by itself, especially for graphs with unbounded degree

    Trajectory selection for the Mariner Jupiter/Saturn 1977 project

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    The use of decision analysis to facilitate a group decision-making problem in the selection of trajectories for the two spacecraft of the Mariner Jupiter/Saturn 1977 Project. A set of 32 candidate trajectory pairs was developed. Cardinal utility function values were assigned to the trajectory pairs, and the data and statistics derived from collective choice rules were used in selecting the science-preferred trajectory pair

    Rapid Mixing for Lattice Colorings with Fewer Colors

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    We provide an optimally mixing Markov chain for 6-colorings of the square lattice on rectangular regions with free, fixed, or toroidal boundary conditions. This implies that the uniform distribution on the set of such colorings has strong spatial mixing, so that the 6-state Potts antiferromagnet has a finite correlation length and a unique Gibbs measure at zero temperature. Four and five are now the only remaining values of q for which it is not known whether there exists a rapidly mixing Markov chain for q-colorings of the square lattice.Comment: Appeared in Proc. LATIN 2004, to appear in JSTA

    Combustion of hydrogen injected into a supersonic airstream (a guide to the HISS computer program)

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    A computer program based on a finite-difference, implicit numerical integration scheme is described for the prediction of hydrogen injected into a supersonic airstream at an angle ranging from normal to parallel to the airstream main flow direction. Results of calculations for flow and thermal property distributions were compared with 'cold flow data' taken by NASA/Langley and show excellent correlation. Typical results for equilibrium combustion are presented and exhibit qualitatively plausible behavior. Computer time required for a given case is approximately one minute on a CDC 7600. A discussion of the assumption of parabolic flow in the injection region is given which demonstrates that improvement in calculation in this region could be obtained by a partially-parabolic procedure which has been developed. It is concluded that the technique described provides an efficient and reliable means for analyzing hydrogen injection into supersonic airstreams and the subsequent combustion

    Exploring family functioning post stroke

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    A.C. vs. In Canada: The Need for a Fresh Approach

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    TB27: Fresh and Dry Weight, Nutrient Elements and Pulping Characteristics of Northern White Cedar, Thuja occidentalis

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    Northern white cedar was selected as an eighth species for complete tree investigation of weight, nutrient elements and pulping characteristics because it comprises approximately 13% of the total softwood growing stock in Maine, but only amounts to about 2% of the total softwood timber cut for all purposes. It is hoped that the information in this bulletin will provide basic information permitting northern white cedar to become a more meaningful segment of the Maine forest economy.https://digitalcommons.library.umaine.edu/aes_techbulletin/1166/thumbnail.jp

    Knowledge and expectations of labour among primigravid women in the public health sector

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    Objectives. We analysed knowledge and expectations of the process and pain of labour in primigravidas attending a local midwifery obstetric unit (MOU). It was anticipated that the results of this study could inform the development of interventions aimed at improving the analgesic care of women delivering at primary health care obstetric units. Design. Qualitative analysis of data obtained from in-depth semi-structured interviews. Setting. A Cape Town MOU. Subjects. 30 black African, Xhosa-speaking primigravidas. Outcome measures. An open-ended interview guide was developed. The themes explored included previous painful experiences, knowledge of labour, expectations of and attitudes towards labour pain, and knowledge of biomedical analgesia. Results. Patients were poorly informed about the process and pain of labour. Most women appeared highly motivated concerning their ability to cope with labour. Most expected pain, but had no concept of the severity or duration of the pain, and knew very little concerning methods available for pain relief in labour. Conclusion. Women at this MOU were poorly prepared for the experience of delivery. Antenatal programmes should incorporate sensitive education concerning the process and pain of labour and the methods available to alleviate pain
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