122 research outputs found
Effect of eccentricity on conjugate natural convection in vertical eccentric annuli
Paper presented at the 6th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 30 June - 2 July, 2008.Combined conduction-free convection heat transfer in
vertical eccentric annuli is numerically investigated using a
finite-difference technique. Numerical results, representing the
heat transfer parameters such as annulus walls temperature,
heat flux, and heat absorbed in the developing region of the
annulus, are presented for a Newtonian fluid of Prandtl number
0.7, fluid-annulus radius ratio 0.5, solid-fluid thermal
conductivity ratio 10, inner and outer wall dimensionless
thicknesses 0.1 and 0.2, respectively, and dimensionless
eccentricities 0.1, 0.3, 0.5, and 0.7. The annulus walls are
subjected to thermal boundary conditions, which are obtained
by heating one wall isothermally whereas keeping the other
wall at inlet fluid temperature. In the present paper, the annulus
heights required to achieve thermal full development for
prescribed eccentricities are obtained. Furthermore, the
variation in the height of thermal full development as function
of the geometrical parameter, i.e., eccentricity is also
investigated.vk201
Conjugate Effects on Steady Laminar Natural Convection Heat Transfer in Vertical Eccentric Annuli
Combined conduction-free convection heat transfer in vertical eccentric annuli is numerically investigated using finite-difference technique. Numerical results are presented for a fluid of Prandtl number 0.7 in an annulus of radius ratio 0.5 and dimensionless eccentricity 0.5. The conjugation effect on the induced flow rate and the total heat absorbed in the annulus is presented for the case of one wall being isothermally heated while the other wall is kept at inlet fluid temperature. The conjugate effects are controlled by solid-fluid conductivity ratio, cylinder walls thickness and dimensionless channel height (i.e. Grashof number). Solid-fluid conductivity ratio is varied over a range that covers practical cases with commonly encountered inner and outer walls thickness. Values of conductivity ratio over which conjugate effect can be neglected have been obtained
Conjugate Effects on Steady Laminar Natural Convection Heat Transfer in Vertical Eccentric Annuli
Combined conduction-free convection heat transfer in vertical eccentric annuli is numerically investigated using finite-difference technique. Numerical results are presented for a fluid of Prandtl number 0.7 in an annulus of radius ratio 0.5 and dimensionless eccentricity 0.5. The conjugation effect on the induced flow rate and the total heat absorbed in the annulus is presented for the case of one wall being isothermally heated while the other wall is kept at inlet fluid temperature. The conjugate effects are controlled by solid-fluid conductivity ratio, cylinder walls thickness and dimensionless channel height (i.e. Grashof number). Solid-fluid conductivity ratio is varied over a range that covers practical cases with commonly encountered inner and outer walls thickness. Values of conductivity ratio over which conjugate effect can be neglected have been obtained
Long-Term Decline in Freshwater Mussels (Bivalvia: Unionidae) of the Western Basin of Lake Erie
Statistical aspects of setting a sampling strategy
Historical information about the variation of the indicator bacteria in a System can be used to help in setting a sampling strategy for future data collection. It is commonly recommended that the water System be divided into zones with the locations within a given zone being more similar to each other than the locations from different zones. A number of samples are then taken at random from each zone. This paper presents a method for estimating the gain in the precision by dividing the water system into zones. Furthermore, a technique is given for estimating the total number of samples required for the water system. This technique is based on the hypothesis testing concept. Two illustrative examples conclude the paper
Proceedings of a Workshop on Statistical Methods for the Assessment of Point Source Pollution
Heterotrophic bacteria in water distribution systems. Part 2. Sampling design for monitoring
International audienc
Exponential families
Exponential families of distributions are parametric dominated families in which the logarithm of probability densities take a simple bilinear form (bilinear in the parameter and a statistic). As a consequence of that special form, sampling models in those families admit a finite-dimensional sufficient statistic irrespective of the sample size, and optimal solutions exist for a number of statistical inference problems: uniformly minimum risk unbiased estimation, uniformly most powerful one-parameter one-sided tests, and so on. Most traditional families of distributions–binomial, multinomial, Poisson, negative binomial, normal, gamma, chi-square, beta, Dirichlet, Wishart, and many others–constitute exponential families. Note, however, that the uniform, logistic, Cauchy, or Student (for given degrees of freedom) location-scale families are not exponential; the double-exponential or Laplace family is exponential for scale only, at fixed location
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