7,637 research outputs found

    Many new voters make the Granite State one to watch in November

    Get PDF
    A third of potential voters in New Hampshire during the fall of 2008 have become eligible to vote in the state. Further, these potential new voters are more likely to identify with the Democratic Party and less likely to identify as Republicans than are established New Hampshire voters, contributing to the state\u27s purple status

    Monotonically improving approximate answers to relational algebra queries

    Get PDF
    We present here a query processing method that produces approximate answers to queries posed in standard relational algebra. This method is monotone in the sense that the accuracy of the approximate result improves with the amount of time spent producing the result. This strategy enables us to trade the time to produce the result for the accuracy of the result. An approximate relational model that characterizes appromimate relations and a partial order for comparing them is developed. Relational operators which operate on and return approximate relations are defined

    Experimental evaluation of heat transfer on a 1030:1 area ratio rocket nozzle

    Get PDF
    A 1030:1 carbon steel, heat-sink nozzle was tested. The test conditions included a nominal chamber pressure of 2413 kN/sq m and a mixture ratio range of 2.78 to 5.49. The propellants were gaseous oxygen and gaseous hydrogen. Outer wall temperature measurements were used to calculate the inner wall temperature and the heat flux and heat rate to the nozzle at specified axial locations. The experimental heat fluxes were compared to those predicted by the Two-Dimensional Kinetics (TDK) computer model analysis program. When laminar boundary layer flow was assumed in the analysis, the predicted values were within 15% of the experimental values for the area ratios of 20 to 975. However, when turbulent boundary layer conditions were assumed, the predicted values were approximately 120% higher than the experimental values. A study was performed to determine if the conditions within the nozzle could sustain a laminar boundary layer. Using the flow properties predicted by TDK, the momentum-thickness Reynolds number was calculated, and the point of transition to turbulent flow was predicted. The predicted transition point was within 0.5 inches of the nozzle throat. Calculations of the acceleration parameter were then made to determine if the flow conditions could produce relaminarization of the boundary layer. It was determined that if the boundary layer flow was inclined to transition to turbulent, the acceleration conditions within the nozzle would tend to suppress turbulence and keep the flow laminar-like

    A metabolite-sensitive, thermodynamically-constrained model of\ud cardiac cross-bridge cycling: Implications for force development during ischemia

    Get PDF
    We present a metabolically regulated model of cardiac active force generation with which we investigate the effects of ischemia on maximum forceproduction. Our model, based on the Rice et al. (2008) model of cross-bridge kinetics, reproduces many of the observed effects of MgATP, MgADP, Pi and H+ on force development while still retaining the force/length/Ca2+ properties of the original model. We introduce three new parameters to account for the competitive binding of H+ to the Ca2+ binding site on troponin C and the binding of MgADP within the cross-bridge cycle. These parameters along with the Pi and H+ regulatory steps within the cross-bridge cycle were constrained using data from the literature and validated using a range of metabolic and sinusoidal length perturbation protocols. The placement of the MgADP binding step between two strongly-bound and force-generating states leads to the emergence of an unexpected effect on the force-MgADP curve, where the trend of the relationship (positive or negative) depends on the concentrations of the other metabolites and [H+]. The model is used to investigate the sensitivity of maximum force production to changes in metabolite concentrations during the development of ischemia

    Comparison of theoretical and experimental thrust performance of a 1030:1 area ratio rocket nozzle at a chamber pressure of 2413 kN/m2 (350 psia)

    Get PDF
    The joint Army. Navy, NASA. Air Force (JANNAF) rocket engine peformnace prediction procedure is based on the use of various reference computer programs. One of the reference programs for nozzle analysis is the Two-Dimensional Kinetics (TDK) Program. The purpose of this report is to calibrate the JANNAF procedure incorporated into the December l984 version of the TDK program for the high-area-ratio rocket engine regime. The calibration was accomplished by modeling the performance of a 1030:1 rocket nozzle tested at NASA Lewis Research Center. A detailed description of the experimental test conditions and TDK input parameters is given. The results show that the computer code predicts delivered vacuum specific impulse to within 0.12 to 1.9 percent of the experimental data. Vacuum thrust coefficient predictions were within + or - 1.3 percent of experimental results. Predictions of wall static pressure were within approximately + or - 5 percent of the measured values. An experimental value for inviscid thrust was obtained for the nozzle extension between area ratios of 427.5 and 1030 by using an integration of the measured wall static pressures. Subtracting the measured thrust gain produced by the nozzle between area ratios of 427.5 and 1030 from the inviscid thrust gain yielded experimental drag decrements of 10.85 and 27.00 N (2.44 and 6.07 lb) for mixture ratios of 3.04 and 4.29, respectively. These values correspond to 0.45 and 1.11 percent of the total vacuum thrust. At a mixture ratio of 4.29, the TDK predicted drag decrement was 16.59 N (3.73 lb), or 0.71 percent of the predicted total vacuum thrust

    What predicts oral health stability in a long-term care population?

    Full text link
    The purpose of this study was to determine whether oral health stability was achievable over time for institutionalized elderly who routinely received comprehensive care and to examine the factors associated with stability. Records of 868 dentate nursing home residents, each with a minimum of 24 months continuous care, were analyzed to determine the number of services by type for each time period between periodic examinations. Presenting dental condition, age, gender, functional status, payer source and facility characteristics were tested as explanatory variables. Oral health status was considered stable when a resident had a“good checkup” (needing no further treatment), otherwise it was coded as unstable. Generalized estimating equations (GEE) were used to analyze predictors of stability over time. Stability over time was achieved in 44% of the study group and negatively associated with male gender, advanced age, and more initial treatment needs. The data show that high levels of initial unmet needs were associated with difficulty achieving oral health stability for institutionalized elderly who routinely received comprehensive care.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75086/1/j.1754-4505.2005.tb01426.x.pd

    Current Developments in Taxation

    Get PDF
    corecore