649 research outputs found

    "As if the beasts spoke": The Animal/Animist/Animated Walt Whitman

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    Love of Comrades: The Urbanization of Community in Walt Whitman\u27s Poetry and Pragmatist Philosophy

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    Argues that the social crisis produced by urbanization shaped Whitman\u27s poetry and pragmatist thought in similar ways, and examines Whitman\u27s struggles with skepticism and relativism in light of his straddling of rural and urban experience, finding that Whitman\u27s untamed flow of sympathy in his urban poems of 1855 and 1856 gives way to an increasing urbane doubt and withdrawal from the city in his 1860 Calamus poems

    A Simple HCCI Engine Model for Control

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    The homogeneous charge compression ignition (HCCI) engine is an attractive technology because of its high efficiency and low emissions. However, HCCI lacks a direct combustion trigger making control of combustion timing challenging, especially during transients. To aid in HCCI engine control we present a simple model of the HCCI combustion process valid over a range of intake pressures, intake temperatures, equivalence ratios, and engine speeds. The model provides an estimate of the combustion timing on a cycle-by-cycle basis. An ignition threshold, which is a function of the in-cylinder motored temperature and pressure is used to predict start of combustion. This model allows the synthesis of nonlinear control laws, which can be utilized for control of an HCCI engine during transients

    A Wandering Mind Is an Unhappy Mind

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    Nozzle Plume Impingement on Spacecraft Surfaces: Effects of Surface Roughness

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    Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. REPORT DATE (DD-MM-YYYY) SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR'S ACRONYM(S) Air Force Research Laboratory (AFMC) AFRL/PRS SPONSOR/MONITOR'S Pollux Drive NUMBER(S) Edwards AFB CA 93524-70448 AFRL-PR-ED-JA-2005-306 DISTRIBUTION / AVAILABILITY STATEMENT Approved for public release; distribution unlimited (PA no. AFRL-ERS-PAS-2005-219). SUPPLEMENTARY NOTES Published in Journal of Spacecraft and Rockets, AIAA-2005-5065. ABSTRACT An experimental and numerical effort was undertaken to assess the effects of a cold gas (T 0 -300 K) nozzle plume impinging on simulated spacecraft surfaces. The nozzle flow impingement is investigated experimentally using a nano-Newton resolution force balance and numerically using the Direct Simulation Monte Carlo (DSMC) numerical technique. The Reynolds number range investigated in this study is from approximately 2 to 350 using nitrogen propellant. The thrust produced by the nozzle was first assessed on a force balance to provide a baseline case. Subsequently, aluminum plates were attached to the same force balance parallel to the plume flow to simulate spacecraft surfaces in proximity to the thruster. Three plates were used in this study, an electropolished plate with smooth surface, and two rough surface plates with equally spaced rectangular and triangular grooves. A 15% degradation in thrust was observed both experimentally and numerically for the plate relative to the free plume expansion case. The effect of surface roughness on thrust was found to be small due to molecules backscattered from the plate to the nozzle plenum wall. Additionally, the influence of surface roughness in the diverging part of the nozzle on thrust was examined numerically and found to be significant at Reynolds numbers less than 10. Abstract An experimental and numerical effort was undertaken to assess the effects of a cold gas (T 0 =300 K) nozzle plume impinging on a simulated spacecraft surface. The nozzle flow impingement is investigated experimentally using a nano-Newton resolution force balance and numerically using the Direct Simulation Monte Carlo (DSMC) numerical technique. The Reynolds number range investigated in this study is from approximately 2 to 600 using nitrogen propellant. The thrust produced by the nozzle was first assessed on a force balance to provide a baseline case. Subsequently, aluminum plates were attached to the same force balance parallel to the plume flow. Three plates were used in this study, an electropolished plate with smooth surface, and two rough surface plates with equally spaced rectangular and triangular grooves. A 15% degradation in thrust was observed both experimentally and numerically for the plate relative to the free plume expansion case. The effect of surface roughness on thrust was found to be small due to molecules back scattered from the plate to the plenum wall. Additionally, the influence of surface rougness in the diverging part of the nozzle on nozzle thrust was examined numerically, and found to be significant at Reynolds numbers on the order or less than 10

    How do patient characteristics influence informal payments for inpatient and outpatient health care in Albania: Results of logit and OLS models using Albanian LSMS 2005

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    Abstract Background Informal payments for health care are common in most former communist countries. This paper explores the demand side of these payments in Albania. By using data from the Living Standard Measurement Survey 2005 we control for individual determinants of informal payments in inpatient and outpatient health care. We use these results to explain the main factors contributing to the occurrence and extent of informal payments in Albania. Methods Using multivariate methods (logit and OLS) we test three models to explain informal payments: the cultural, economic and governance model. The results of logit models are presented here as odds ratios (OR) and results from OLS models as regression coefficients (RC). Results Our findings suggest differences in determinants of informal payments in inpatient and outpatient care. Generally our results show that informal payments are dependent on certain characteristics of patients, including age, area of residence, education, health status and health insurance. However, they are less dependent on income, suggesting homogeneity of payments across income categories. Conclusions We have found more evidence for the validity of governance and economic models than for the cultural model.</p

    Effect of short-acting beta blocker on the cardiac recovery after cardiopulmonary bypass

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    The objective of this study was to investigate the effect of beta blocker on cardiac recovery and rhythm during cardiac surgeries. Sixty surgical rheumatic heart disease patients were received esmolol 1 mg/kg or the same volume of saline prior to removal of the aortic clamp. The incidence of cardiac automatic re-beat, ventricular fibrillation after reperfusion, the heart rate after steady re-beat, vasoactive drug use during weaning from bypass, the posterior parallel time and total bypass time were decreased by esmolol treatment. In conclusion: Esmolol has a positive effect on the cardiac recovery in cardiopulmonary bypass surgeries
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