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J.C.R. Turner

Bio: J.C.R. Turner is an academic researcher from University of Cambridge. The author has contributed to research in topics: Ion exchange & Diffusion. The author has an hindex of 6, co-authored 7 publications receiving 255 citations.

Papers
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Journal ArticleDOI
TL;DR: In this paper, the electrical conductivity of fluidized beds has been extended to cover the full range of conductivity ratio of the two phases, α and a wide range of dispersed phase volume fraction, f.

114 citations

Journal ArticleDOI
TL;DR: The results of tracer experiments can depend on the methods of injection and measurement of the tracer when the fluid velocity is not uniform through the injection/measurement planes as discussed by the authors.

84 citations

Journal ArticleDOI
TL;DR: In this paper, the liquid-side mass transfer coefficient for the exchange of H + and Na + ions between aqueous chloride solutions and Zeo-Karb 225 ion-exchange resin was measured.

22 citations

Journal ArticleDOI
TL;DR: In this paper, it was shown that the gradient of chemical potential is the natural force for diffusion in binary isothermal mixture, and that in ideal systems it does not matter which approach is used, but where non-ideality is marked, the thermal approach would appear to have advantage.

20 citations

Journal ArticleDOI
TL;DR: In this paper, the non-linear differential equation describing thermal diffusion in a uniform liquid mixture is derived and solved numerically, and practical results using two aqueous solutions are given.

15 citations


Cited by
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Journal ArticleDOI
TL;DR: In this paper, the authors measured the effective thermal conductivity of mixtures of Al 2O3 and CuO, dispersed in water, vacuum pump, engine oil, and ethylene glycol.
Abstract: Effective thermal conductivity of mixtures of e uids and nanometer-size particles is measured by a steady-state parallel-plate method. The tested e uids contain two types of nanoparticles, Al 2O3 and CuO, dispersed in water, vacuum pump e uid, engine oil, and ethylene glycol. Experimental results show that the thermal conductivities of nanoparticle ‐e uid mixtures are higher than those of the base e uids. Using theoretical models of effective thermal conductivity of a mixture, we have demonstrated that the predicted thermal conductivities of nanoparticle ‐e uid mixtures are much lower than our measured data, indicating the dee ciency in the existing models when used for nanoparticle ‐e uid mixtures. Possible mechanisms contributing to enhancement of the thermal conductivity of the mixtures are discussed. A more comprehensive theory is needed to fully explain the behavior of nanoparticle ‐e uid mixtures. Nomenclature cp = specie c heat k = thermal conductivity L = thickness Pe = Peclet number P q = input power to heater 1 r = radius of particle S = cross-sectional area T = temperature U = velocity of particles relative to that of base e uids ® = ratio of thermal conductivity of particle to that of base liquid ¯ = .® i 1/=.® i 2/ ° = shear rate of e ow Ω = density A = volume fraction of particles in e uids Subscripts

2,156 citations

Journal ArticleDOI
TL;DR: In this paper, three new lumped-parameter models have been developed for the interpretation of environmental radioisotope data in groundwater systems, and the applicability of these models were tested by the reinterpretation of several known case studies (Modry Dul, Cheju Island, Rasche Spring and Grafendorf).

742 citations

Journal ArticleDOI
TL;DR: In this article, it is shown that similarly to the movement in capillaries, also in other dispersive systems, the distinction between the concentration of solute in res is also made by known and new transformations.

718 citations

Reference BookDOI
22 Jul 2008

652 citations

Journal ArticleDOI
TL;DR: In this paper, it was shown that the effective conductivity of the material in terms of the average thermal (or electrical) dipole strength of a particle is approximately equal to a weighted sum of the fluxes across the areas near contact points.
Abstract: The material under investigation consists of particles of relatively large conductivity embedded or immersed in a matrix, the volume fraction of the particles being so high that they are in, or nearly in, contact. The particles are arranged randomly, and the material is statistically homogeneous. A general formula gives the effective conductivity of the material in terms of the average thermal (or electrical) dipole strength of a particle. The thermal flux across the surface of a particle is concentrated in areas near points of contact with another particle, and the dipole strength is approximately equal to a weighted sum of the fluxes across the areas near contact points. It is thus necessary to calculate the flux between two adjoining particles at different temperatures, and we do this by solving numerically an integral equation for the distribution of temperature over the (locally spherical) surface of one of the particles near the contact point. The flux between the two particles is found to be proportional to loge ah when a2 2h/a ≫ 1 and to log e a when a 2h/a ≪ 1, where h is the minimum gap between the particle surfaces, a~ 1 the mean of their local curvatures, and a the ratio of the conductivities of the particles and the matrix. In the case of two particles pressed together to form a circular flat spot of radius p , the flux occurs almost wholly in the particle material, and is proportional to p when ap/a ≫ 1. Explicit approximate results are obtained for the effective conductivity of the granular material in the case of uniform spherical particles. For a close-packed bed of particles making point contact the effective conductivity is found to be 4.0 k log e a where k is the matrix conductivity. This asymptotic relation (applicable when a ≫ 1) is seen to be consistent with the available measurements of the conductivity of packed beds of spheres. Values of the effective conductivity for packed beds of particles of different shape are not expected to be greatly different.

535 citations