11,393 research outputs found

    Analysis of non-premixed turbulent reacting flows

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    Studies of chemical reactions occurring in turbulent flows are important in the understanding of combustion and other applications. Current numerical methods are limited in their applications due to the numerical resolution required to completely capture all length scales, but, despite the fact that realistic combustion cannot be solved completely, numerical simulations can be used to give insight into the interaction between the processes of turbulence and chemical reaction. The objective was to investigate the effects of turbulent motion on the effects of chemical reaction to gain some insight on the interaction of turbulence, molecular diffusion, and chemical reaction to support modeling efforts. A direct turbulence simulation spectral code was modified to include the effects of chemical reaction and applied to an initial value problem of chemical reaction between non-premixed species. The influence of hydrodynamics on the instantaneous structure of the reaction was investigated. The local scalar dissipation rates and the local reaction rates were examined to determine the influence of vorticity or rate of strain on the reaction and the structure of the scalar field

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    Pin++: An Object-oriented Framework for Writing Pintools

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    This paper presents a framework named Pin++. Pin++ is an object-oriented framework that uses template metaprogramming to implement Pintools, which are analysis tools for the dynamic binary instrumentation tool named Pin. The goal of Pin++ is to simplify programming a Pintool and promote reuse of its components across different Pintools. Our results show that Pintools implemented using Pin++ can have a 54% reduction in complexity, increase its modularity, and up to 60% reduction in instrumentation overhead

    Results from the LSND Neutrino Oscillation Search

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    The Liquid Scintillator Neutrino Detector (LSND) at the Los Alamos Meson Physics Facility sets bounds on neutrino oscillations in the appearance channel nu_mu_bar --> nu_e_bar by searching for the signature of the reaction nu_e_bar p --> e^+ n: an e+^+ followed by a 2.2MeV gamma ray from neutron capture. Five e^{+/-} -- gamma coincidences are observed in time with the LAMPF beam, with an estimated background of 6.2 events. The 90\% confidence limits obtained are: Delta (m^2) < 0.07eV^2 for sin^2 (2theta) = 1, and sin^2(2theta) < 6 10^{-3} for Delta (m^2) > 20 eV^2.Comment: 10 pages, uses REVTeX and epsf macro

    Infection and Twiddler Syndrome in a Dog With Addison\u27s Disease, Complete Heart Block, and Wandering Artificial Pacemakers

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    Third-degree heart block developed in an obese seven-year-old dog with adrenal cortical failure. After three days of extensive medial therapy and use of a temporary transvenous pacemaker, a transthoracic permanent pacemaker was implanted in the usual paracostal location. After two years of normal function, the pulse generator suddenly migrated to a ventral location in the flank and became surrounded by an abscess. Intermittent pacing failure ensued. Medical therapy with antibiotics failed to eliminate infection until the infected pacemaker and site were excised surgically. A new pacemaker was placed on the opposite side and functioned well for two months. Subsequent migration and rotation of the new pacemaker led to spiral twisting of the lead and dislodgment of the corkscrew electrode from the myocardium in a syndrome analogous to Twiddler\u27s syndrome in man. The dog presently is 10 years old and asymptomatic with a nonpaced ventricular rhythm of 60 beats per minute and an usual chest radiograph

    A life course approach to diet, nutrition and the prevention of chronic diseases

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    Abstract Objective: To briefly review the current understanding of the aetiology and prevention of chronic diseases using a life course approach, demonstrating the life-long influences on the development of disease. Design: A computer search of the relevant literature was done using Medline-‘life cycle' and ‘nutrition' and reviewing the articles for relevance in addressing the above objective. Articles from references dated before 1990 were followed up separately. A subsequent search using Clio updated the search and extended it by using ‘life cycle', ‘nutrition' and ‘noncommunicable disease' (NCD), and ‘life course'. Several published and unpublished WHO reports were key in developing the background and arguments. Setting: International and national public health and nutrition policy development in light of the global epidemic in chronic diseases, and the continuing nutrition, demographic and epidemiological transitions happening in an increasingly globalized world. Results of review: There is a global epidemic of increasing obesity, diabetes and other chronic NCDs, especially in developing and transitional economies, and in the less affluent within these, and in the developed countries. At the same time, there has been an increase in communities and households that have coincident under- and over-nutrition. Conclusions: The epidemic will continue to increase and is due to a lifetime of exposures and influences. Genetic predisposition plays an unspecified role, and with programming during fetal life for adult disease contributing to an unknown degree. A global rise in obesity levels is contributing to a particular epidemic of type 2 diabetes as well as other NCDs. Prevention will be the most cost-effective and feasible approach for many countries and should involve three mutually reinforcing strategies throughout life, starting in the antenatal perio

    Estimating Peak Demand for Beach Parking Spaces

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    The United States Army Corps of Engineers planning guidance stipulates that in order for local beach communities to qualify for Federal cost share funds for Hurricane and Storm Damage Reduction beach renourishment projects, the community must provide public beach access and parking to satisfy peak demand. This study presents a method for estimating peak demand for beach parking spaces in the presence of parking constraints. A Tobit regression model is developed to estimate the number of parking spaces that would be necessary to meet unconstrained demand on a given percentage of peak demand days. For example, the model can be used to estimate the number of parking spaces that would be adequate to meet peak demand on 90% of peak parking days. The Tobit model provides a promising framework for estimating peak parking demand under constrained parking conditions, a situation that characterizes most beach communities.

    CORBA-JS: An Open-Standards Framework for Distributed Object Computing over the Web

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    poster abstractDistributed object computing (DOC) is a well-established software engineering paradigm for implementing distributed real-time and embedded (DRE) systems, such as real-time monitoring systems. Likewise, CORBA is a well-established DOC open-standard used in DRE systems. Due to many technological limitations, DOC was traditionally unavailable in Web-based applications (i.e., stateful applications that communicate over HTTP, and are accessible via a Web browser) without the use of proprietary, custom technologies. The problem with using proprietary, custom technology is it creates fragmentation in the solution space where some solutions are not available to all end-users (e.g., Web sites that only work within a certain Web browser because of the used technology). With the advent of HTML5 and WebSockets, which is an open-standard for enabling two-way communication over HTTP, DOC now has the necessary technological foundations to be realized within Web applications without the use of proprietary, custom technologies. To date, however, no researchers have attempted to apply DOC over HTTP using well-established DOC open-standards, such as CORBA. This research therefore is an initial investigation into implementing CORBA atop of HTML5 and WebSockets. As part of this research, we are investigating the challenges in realizing the solution, and proposing ways to improve the target programming languages and CORBA specification. Doing so will enable developers to create feature-rich real-time Web applications that improve upon current state-of-the-art approaches, e.g., Asynchronous XML and JavaScript (AJAX), that are resource intensive (e.g., use a lot of CPU, network bandwidth, and memory) and hard to program
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