8,477 research outputs found
Significance of radiation models in investigating the flow phenomena around a Jovian entry body
Formulation is presented to demonstrate the significance of a simplified radiation model in investigating the flow phenomena in the viscous radiating shock layer of a Jovian entry body. The body configurations used are a 55 degree sphere cone and 50 degree hyperboloid. A nongray absorption model for hydrogen-helium gas is developed which consists of 30 steps over the spectral range of 0 to 20 eV. By employing this model, results were obtained for temperature, pressure, density, the shock layer and along the body surface. These are compared with results of two sophisticated radiative transport models available in the literature
Influence of nonequilibrium radiation and shape change on aerothermal environment of a Jovian entry body
The influence of nonequilibrium radiative energy transfer and the effect of probe configuration changes on the flow phenomena around a Jovian entry body are investigated. The radiating shock layer flow is assumed to be axisymmetric, viscous, laminar and in chemical equilibrium. The radiative transfer equations are derived under nonequilibrium conditions which include multilevel energy transitions. The equilibrium radiative transfer analysis is performed with an existing nongray radiation model which accounts for molecular band, atomic line, and continuum transitions. The nonequilibrium results are obtained with and without ablation injection in the shock layer. The nonequilibrium results are found to be greatly influenced by the temperature distribution in the shock layer. In the absence of ablative products, the convective and radiative heating to the entry body are reduced under nonequilibrium conditions. The influence of nonequilibrium is found to be greater at higher entry altitudes. With coupled ablation and carbon phenolic injection, 16 chemical species are used in the ablation layer for radiation absorption. Equilibrium and nonequilibrium results are compared under peak heating conditions
Short and long-term relationship between physician density on infant mortality: a longitudinal econometric analysis
While countries with higher levels of human resources for health typically have better population health, the evidence that increases in the level of human resources for health leads to improvements in population health is limited. We provide estimates of short-run and long-term effects of physician density on infant mortality. We use a dynamic regression model that allows an estimation of both short- and long-run effects of physician density on infant mortality. We also used instrumental variables analysis to identify the causal effect of physician density on health. We estimate that increasing the number of physicians by one per 1,000 population decreases the infant mortality rate by 15% within five years and by 45% in the long-run. We find all countries are moving towards their own steady state at around 3% a year and are only half way there after 15 years. We conclude that the long-run effects of human resources for health are substantially larger than previously estimated. Our results suggest that health sector inputs can play a role in reducing infant mortality. However, meeting the Millennium Development Goal of reducing child mortality rate by two thirds from 1990 to 2015 would have required much earlier action.Physician density, infant mortality, longitudinal, eocnometric
Sugars of pearl millet [Pennisetum americanum (L.) Leeke] grains
The sugars in the grains of nine pearl millet cultivars were fractionated through a Biogel column. Five different sugars‘(stachyose, raffinose, sucrose, glucose, and fructose) were identified. Sucrose was predominant in all the cultivars. Raffinose content was high as compared to other cereals, and maltose was absen
Application of Runge Kutta time marching scheme for the computation of transonic flows in turbomachines
Numerical solutions of the unsteady Euler equations are obtained using the classical fourth order Runge Kutta time marching scheme. This method is fully explicit and is applied to the governing equations in the finite volume, conservation law form. In order to determine the efficiency of this scheme for solving turbomachinery flows, steady blade-to-blade solutions are obtained for compressor and turbine cascades under subsonic and transonic flow conditions. Computed results are compared with other numerical methods and wind tunnel measurements. The study also focuses on other important numerical aspects influencing the performance of the algorithm and the solution accuracy such as grid types, boundary conditions and artificial viscosity. For this purpose, H, O, and C type computational grids as well as characteristic and extrapolation type boundary conditions are included in solution procedures
Influence of nonequilibrium radiation and shape change on aerothermal environment of Jovian entry body
Radiative transfer equations are derived under nonequilibrium conditions which include multilevel energy transitions. The nonequalibrium results, obtained with and without ablation injection in the shock layer, are found to be greatly influenced by the temperature distribution in the shock layer. In the absence of ablative products, the convective and radiative heating to the entry body are reduced significantly under nonequilibrium conditions. The influence of nonequilibrium is found to be greater at higher entry altitudes. With coupled ablation and carbon phenolic injection, 16 chemical species are used in the ablation layer for radiation absorption. Equilibrium and nonequilibrium results are compared under peak heating conditions. A 45 degree sphere cone, a 35 degree hyperboloid, and a 45 degree ellipsoid were used to study probe shape change. Results indicate that the shock layer flow field and heat transfer to the body are influenced significantly by the probe shape change. The effect of shape change on radiative heating of the afterbodies is found to be considerably larger for the sphere cone and ellipsoid than for the hyperboloid
Analysis of longwave radiation for the Earth-atmosphere system
Accurate radiative transfer models are used to determine the upwelling atmospheric radiance and net radiative flux in the entire longwave spectral range. The validity of the quasi-random band model is established by comparing the results of this model with those of line-by-line formulations and with available theoretical and experimental results. Existing radiative transfer models and computer codes are modified to include various surface and atmospheric effects (surface reflection, nonequilibrium radiation, and cloud effects). The program is used to evaluate the radiative flux in clear atmosphere, provide sensitivity analysis of upwelling radiance in the presence of clouds, and determine the effects of various climatological parameters on the upwelling radiation and anisotropic function. Homogeneous and nonhomogeneous gas emissivities can also be evaluated under different conditions
Association between coverage of maternal and child health interventions, and under-5 mortality: a repeated cross-sectional analysis of 35 sub-Saharan African countries
Background: Infant and child mortality rates are among the most important indicators of child health, nutrition, implementation of key survival interventions, and the overall social and economic development of a population. In this paper, we investigate the role of coverage of maternal and child health (MNCH) interventions in contributing to declines in child mortality in sub-Saharan Africa. Design: Data are from 81 Demographic and Health Surveys from 35 sub-Saharan African countries. Using ecological time-series and child-level regression models, we estimated the effect of MNCH interventions (summarized by the percent composite coverage index, or CCI) on child mortality with in the first 5 years of life net of temporal trends and covariates at the household, maternal, and child levels. Results: At the ecologic level, a unit increase in standardized CCI was associated with a reduction in under-5 child mortality rate (U5MR) of 29.0 per 1,000 (95% CI: −43.2, −14.7) after adjustment for survey period effects and country-level per capita gross domestic product (pcGDP). At the child level, a unit increase in standardized CCI was associated with an odds ratio of 0.86 for child mortality (95% CI: 0.82–0.90) after adjustment for survey period effect, country-level pcGDP, and a set of household-, maternal-, and child-level covariates. Conclusions: MNCH interventions are important in reducing U5MR, while the effects of economic growth in sub-Saharan Africa remain weak and inconsistent. Improved coverage of proven life-saving interventions will likely contribute to further reductions in U5MR in sub-Saharan Africa
Giant Meterwave Radio Telescope observations of an M2.8 flare: insights into the initiation of a flare-coronal mass ejection event
We present the first observations of a solar flare with the GMRT. An M2.8
flare observed at 1060 MHz with the GMRT on Nov 17 2001 was associated with a
prominence eruption observed at 17 GHz by the Nobeyama radioheliograph and the
initiation of a fast partial halo CME observed with the LASCO C2 coronograph.
Towards the start of the eruption, we find evidence for reconnection above the
prominence. Subsequently, we find evidence for rapid growth of a vertical
current sheet below the erupting arcade, which is accompanied by the flare and
prominence eruption.Comment: Accepted for publication in Solar Physic
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Changing patterns of social inequalities in anaemia among women in India: cross-sectional study using nationally representative data
Objectives: To examine the patterns of social inequalities in anaemia over time among women of reproductive age in India. Design: Repeated cross-sectional study using nationally representative data from the 1998/1999 and 2005/2006 National Family Health Surveys of India. Multivariate modified Poisson regression models were used to assess trends and social inequalities in anaemia. Setting: India. Population 164 600 ever-married women aged 15–49 years (n=79 197 in 1998/1999 and n=85 403 in 2005/2006) from 25 Indian states. Main outcome measure Anaemia status defined by haemoglobin level (<12 g/dl in non-pregnant women, haemoglobin<11 g/dl for pregnant women). Results: Over the 7-year period, anaemia prevalence increased significantly from 51.3% (95% CI 50.6% to 52%) to 56.1% (95% CI 55.4% to 56.8%) among Indian women. This corresponded to a 1.11-fold increase in anaemia prevalence (95% CI 1.09 to 1.13) after adjustment for age and parity, and 1.08-fold increase (95% CI 1.06 to 1.10) after further adjustment for wealth, education and caste. There was marked state variation in anaemia prevalence; in only 4 of the 25 states did anaemia prevalence significantly decline. In both periods, anaemia was socially patterned, being positively associated with lower wealth status, lower education and belonging to scheduled tribes and scheduled castes. In this context of overall increasing anaemia prevalence, adjusted relative and absolute socioeconomic inequalities in anaemia by wealth, education and caste have narrowed significantly over time. Conclusions: The significant increase in anaemia among India's women during this recent period is a matter of concern, and in contrast to secular improvements in other markers of women's health and nutritional status. While socioeconomic inequalities in anaemia persist, the relative and absolute inequalities in anaemia have decreased over time. Future research should explore the causes for these changing patterns, and inform the policy and programmatic response to address anaemia and its inequalities in this vulnerable population
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