34,777 research outputs found

    NASTRAN - A summary of the functions and capabilities of the NASA structural analysis computer system

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    Description of general purpose digital computer program /NASTRAN/ for analysis of elastic structures under various loading conditions using finite element method approac

    Unsung heroes: Constituency election agents in British general elections

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    Despite their central role in the electoral process, constituency agents have been largely overlooked by political scientists and this article seeks to rectify the omission. It sketches the origins and development of the role of agent from the late 19th century and suggests that a serious rethink of the role took place in the 1990s. Survey-based evidence about the social characteristics of agents is presented confirming that they are largely middle-aged, middle-class, well-educated men. They are also becoming more experienced, offer realistic assessments of the impact of constituency campaigning and, arguably, many take a long-term view of how their party's support can be maximised

    Prader-Willi syndrome: are there population differences?

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    A 15 1/2-year-old black female with features consistent with the Prader-Willi syndrome is reported. This is the second case report of a black individual and the first case of a black female with the Prader-Willi syndrome. There is an apparent paucity of blacks reported with this condition. Whether this difference is a true difference or represents under-reporting is not known. We urge reporting of individuals representing other racial groups with this disorder and suggest population studies to determine the incidence as well as the true population difference in the Prader-Willi syndrome

    A knowledge-based flight status monitor for real-time application in digital avionics systems

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    The Dryden Flight Research Facility of the National Aeronautics and Space Administration (NASA) Ames Research Center (Ames-Dryden) is the principal NASA facility for the flight testing and evaluation of new and complex avionics systems. To aid in the interpretation of system health and status data, a knowledge-based flight status monitor was designed. The monitor was designed to use fault indicators from the onboard system which are telemetered to the ground and processed by a rule-based model of the aircraft failure management system to give timely advice and recommendations in the mission control room. One of the important constraints on the flight status monitor is the need to operate in real time, and to pursue this aspect, a joint research activity between NASA Ames-Dryden and the Royal Aerospace Establishment (RAE) on real-time knowledge-based systems was established. Under this agreement, the original LISP knowledge base for the flight status monitor was reimplemented using the intelligent knowledge-based system toolkit, MUSE, which was developed under RAE sponsorship. Details of the flight status monitor and the MUSE implementation are presented

    An alternative method for assessing the value of the Southern Oscillation Index (SOI), including case studies of its value for crop management in the northern grainbelt of Australia

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    Previous studies have identified extra profit that could result from selecting management options according to particular phases of the Southern Oscillation Index (SOI). Those studies identified optimal decisions for each phase and the value of these decisions. However, this may have overestimated the value of SOI-based management through a lack of data for independent evaluation. This study compares the previous approach with a new method based on a simple sampling technique (analogous to leave-one-out cross validation) that estimates the range of future outcomes when independent validation data are not available. The new method gave much-improved estimates of the mean and variance of the value of the SOI for management. In studies involving wheat-growing in southern Queensland, this method indicated that management according to the April–May SOI phase yielded either small long-term increases (in 4 of 6 cases) or decreases (in 2 of 6 cases) in profit. There was considerable heterogeneity among phases, and the annual variance of the outcomes was large relative to the long-term average value in all 6 cases. Consequently, unless a strategy is applied long term (at least 10 years), there is a relatively high likelihood of higher or lower profit than for non-strategic management. The likelihood of increased and decreased short-term profit is approximately equal. In all 6 case studies, the long-term average economic value of SOI-adjusted management was less than, or equal to, the economic value of 1 mm of extra plant-available soil moisture at sowing

    A Third Planet Orbiting HIP 14810

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    We present new precision radial velocities and a three-planet Keplerian orbit fit for the V = 8.5, G5 V star HIP 14810. We began observing this star at Keck Observatory as part of the N2K Planet Search Project. Wright et al. (2007) announced the inner two planets to this system, and subsequent observations have revealed the outer planet planet and the proper orbital solution for the middle planet. The planets have minimum masses of 3.9, 1.3, and 0.6 M_Jup and orbital periods of 6.67, 147.7, and 952 d, respectively. We have numerically integrated the family of orbital solutions consistent with the data and find that they are stable for at least 10^6 yr. Our photometric search shows that the inner planet does not transit.Comment: ApJL, accepte

    Numerical Evidence for the Observation of a Scalar Glueball

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    We compute from lattice QCD in the valence (quenched) approximation the partial decay widths of the lightest scalar glueball to pairs of pseudoscalar quark-antiquark states. These predictions and values obtained earlier for the scalar glueball's mass are in good agreement with the observed properties of fJ(1710)f_J(1710) and inconsistent with all other observed meson resonances.Comment: 12 pages of Latex, 3 PostsScript figures as separate uufil

    Statistical correlation analysis for comparing vibration data from test and analysis

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    A theory was developed to compare vibration modes obtained by NASTRAN analysis with those obtained experimentally. Because many more analytical modes can be obtained than experimental modes, the analytical set was treated as expansion functions for putting both sources in comparative form. The dimensional symmetry was developed for three general cases: nonsymmetric whole model compared with a nonsymmetric whole structural test, symmetric analytical portion compared with a symmetric experimental portion, and analytical symmetric portion with a whole experimental test. The theory was coded and a statistical correlation program was installed as a utility. The theory is established with small classical structures

    Multi-objective optimisation of wastewater treatment plant control to reduce greenhouse gas emissions.

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    PublishedResearch Support, Non-U.S. Gov'tThis is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.watres.2014.02.018This study investigates the potential of control strategy optimisation for the reduction of operational greenhouse gas emissions from wastewater treatment in a cost-effective manner, and demonstrates that significant improvements can be realised. A multi-objective evolutionary algorithm, NSGA-II, is used to derive sets of Pareto optimal operational and control parameter values for an activated sludge wastewater treatment plant, with objectives including minimisation of greenhouse gas emissions, operational costs and effluent pollutant concentrations, subject to legislative compliance. Different problem formulations are explored, to identify the most effective approach to emissions reduction, and the sets of optimal solutions enable identification of trade-offs between conflicting objectives. It is found that multi-objective optimisation can facilitate a significant reduction in greenhouse gas emissions without the need for plant redesign or modification of the control strategy layout, but there are trade-offs to consider: most importantly, if operational costs are not to be increased, reduction of greenhouse gas emissions is likely to incur an increase in effluent ammonia and total nitrogen concentrations. Design of control strategies for a high effluent quality and low costs alone is likely to result in an inadvertent increase in greenhouse gas emissions, so it is of key importance that effects on emissions are considered in control strategy development and optimisation.Thanks are given for the Matlab/Simulink implementation of the BSM2 from the Department of Industrial Electrical Engineering and Automation, Lund University, Lund, Sweden. Christine Sweetapple gratefully acknowledges financial support provided by the University of Exeter in the form of a studentship
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