Delta method, an empirical drag buildup technique

An empirical drag correlation technique was developed from analysis of 19 subsonic and supersonic military aircraft and 15 advanced or supercritical airfoil configurations which can be applied in conceptual and advanced aircraft design activities. The Delta Method may be used for estimating the clean wing drag polar for cruise and maneuver conditions up to buffet onset, and to approximately Mach 2.0. This technique incorporates a unique capability of predicting the off-design performance of advanced or supercritical airfoil sections. The buffet onset limit may also be estimated. The method is applicable to wind tunnel models as well as to full scale configurations. This technique has been converted into a computer code for use on the IBM 360 and CDC 7600 computer facilities at NASA AMES. Results obtained using this method to predict known aircraft characteristics are good and agreement can be obtained within a degree of accuracy judged to be sufficient for the initial processes of preliminary design

Generalized poisson brackets and nonlinear Liapunov stability application to reduces mhd

A method is presented for obtaining Liapunov functionals (LF) and proving nonlinear stability. The method uses the generalized Poisson bracket (GPB) formulation of Hamiltonian dynamics. As an illustration, certain stationary solutions of ideal reduced MHD (RMHD) are shown to be nonlinearly stable. This includes Grad-Shafranov and Alfven solutions

Systematically searching for and assessing the literature for self-management of chronic pain: A lay users' perspective

© 2014 Schofield et al.; licensee BioMed Central Ltd. Background: The Engaging with older adults in the development of strategies for the self management of chronic pain (EOPIC) study aims to design and develop self management strategies to enable older adults to manage their own pain. Involving older adults in research into chronic pain management will better enable the identification and development of strategies that are more appropriate for their use, but how can perspectives really be utilised to the best possible outcomes?. Method. Seven older adults were recruited through a local advertising campaign to take part. We also invited participants from the local pain services, individuals who had been involved in earlier phase of the EOPIC study and a previous ESRC funded project. The group undertook library training and research skills training to facilitate searching of the literature and identified sources of material. A grading tool was developed using perceived essential criteria identified by the older adults and material was graded according to the criteria within this scale. Results: Fifty-seven resources from over twenty-eight sources were identified. These materials were identified as being easily accessible, readable and relevant. Many of the web based materials were not always easy to find or readily available so they were excluded by the participants. All but one were UK based. Forty-four items were identified as meeting the key criteria for inclusion in the study. This included five key categories as follows; books, internet, magazines, leaflets, CD's/Tapes. Conclusion: This project was able to identify a number of exemplars of self management material along with some general rules regarding the categories identified. We must point out that the materials identified were not age specific, were often locally developed and would need to be adapted to older adults with chronic pain. For copyright issues we have not included them in this paper. The key message is really related to the format rather than the content. However, the group acknowledge that these may vary according to the requirements of each individual older adult and therefore recommend the development of a leaflet to help others in their search for resources. This leaflet has been developed as part of Phase IV of the EOPIC study

GeneRank: Using search engine technology for the analysis of microarray experiments

Copyright @ 2005 Morrison et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Background: Interpretation of simple microarray experiments is usually based on the fold-change of gene expression between a reference and a "treated" sample where the treatment can be of many types from drug exposure to genetic variation. Interpretation of the results usually combines lists of differentially expressed genes with previous knowledge about their biological function. Here we evaluate a method – based on the PageRank algorithm employed by the popular search engine Google – that tries to automate some of this procedure to generate prioritized gene lists by exploiting biological background information. Results: GeneRank is an intuitive modification of PageRank that maintains many of its mathematical properties. It combines gene expression information with a network structure derived from gene annotations (gene ontologies) or expression profile correlations. Using both simulated and real data we find that the algorithm offers an improved ranking of genes compared to pure expression change rankings. Conclusion: Our modification of the PageRank algorithm provides an alternative method of evaluating microarray experimental results which combines prior knowledge about the underlying network. GeneRank offers an improvement compared to assessing the importance of a gene based on its experimentally observed fold-change alone and may be used as a basis for further analytical developments

Transport Properties in Nontwist Area-Preserving Maps

Nontwist systems, common in the dynamical descriptions of fluids and plasmas, possess a shearless curve with a concomitant transport barrier that eliminates or reduces chaotic transport, even after its breakdown. In order to investigate the transport properties of nontwist systems, we analyze the barrier escape time and barrier transmissivity for the standard nontwist map, a paradigm of such systems. We interpret the sensitive dependence of these quantities upon map parameters by investigating chaotic orbit stickiness and the associated role played by the dominant crossing of stable and unstable manifolds. (C) 2009 American Institute of Physics. [doi: 10.1063/1.3247349]CNPqCAPESFAPESPFINEP/CNENU.S. Department of Energy DEFG03-96ER-54346Institute for Fusion Studie

Effect of pressure on the crystal structure of L-serine-I and the crystal structure of L-serine-II at 5.4 GPa

The crystal structure of L-serine has been determined at room temperature at pressures between 0.3 and 4.8 GPa. The structure of this phase ( hereafter termed L-serine-I), which consists of the molecules in their zwitterionic tautomer, is orthorhombic, space group P2(1)2(1)2(1). The least compressible cell dimension (c), corresponds to chains of head-to-tail NH ... carboxylate hydrogen bonds. The most compressible direction is along b, and the pressure-induced distortion in this direction takes the form of closing up voids in the middle of R-type hydrogen-bonded ring motifs. This occurs by a change in the geometry of hydrogen-bonded chains connecting the hydroxyl groups of the - CH2OH side chains. These hydrogen bonds are the longest conventional hydrogen bonds in the system at ambient pressure, having an O ... O separation of 2.918 (4) Angstrom and an O ... O ... O angle of 148.5 (2)degrees; at 4.8 GPa these parameters are 2.781 (11) and 158.5 (7) degrees. Elsewhere in the structure one NH ... O interaction reaches an N ... O separation of 2.691 (13) Angstrom at 4.8 GPa. This is amongst the shortest of this type of interaction to have been observed in an amino acid crystal structure. Above 4.8 GPa the structure undergoes a single-crystal-to-single-crystal phase transition to a hitherto uncharacterized polymorph, which we designate L-serine-II. The OH ... OH hydrogen-bonded chains of L-serine-I are replaced in L-serine-II by shorter OH ... carboxyl interactions, which have an O ... O separation of 2.62 (2) Angstrom. This phase transition occurs via a change from a gauche to an anti conformation of the OH group, and a change in the NCalphaCO torsion angle from -178.1 (2)degrees at 4.8 GPa to -156.3 (10)degrees at 5.4 GPa. Thus, the same topology appears in both crystal forms, which explains why it occurs from one single- crystal form to another. The transition to L-serine-II is also characterized by the closing-up of voids which occur in the centres of other R-type motifs elsewhere in the structure. There is a marked increase in CH ... O hydrogen bonding in both phases relative to L-serine-I at ambient pressure.</p