Porous hemispherical

Cones, medicated Cones are light, porous hemispherical masses of sucrose and egg albumin, used as a vehicle for homeopathic medications. The cones, also called disks, are designated (in millimeters) according to size by the diameter of the base. The common size (No. 6) should absorb about 2 drops of dispensing alcohol. Cones are medicated by adding a sufficient quantity of the dilution to saturate them and pouring off the excess liquid. ... 

The device, presented in Fig. 2.25 (without electrodes 1 and 6) has been used in [136] for the determination of K by the so-called stationary bubble method . A foam film forms on the porous plate acquiring the shape of a hemisphere. The radius of curvature R is practically equal to the radius of the perimeter at the base of the hemispherical bubble. Because of the gas passing from the bubble through the foam film into the atmosphere, R decreases with time t. The values of r are measured and K is calculated from... 

Then the anodic alumina layer formed was removed chemically in the selective etchant composed of phosphoric (6 wt.%) and chromic (1.8 wt.%) acids at 60 C. Hemispheric etching pits - replica of the alumina cell bottoms - remain on the surface of the aluminum foil. The second porous anodization of aluminum was made. At this stage, the pores on the aluminum foil surface arise not in random way but at the sites of primary alumina cell Imprints to repeat the cell size. The pore diameter and spacing are dictated by the parameters of the anodization process, specifically by the electrolyte composition and the anodization voltage. The alumina film thickness is defined by the anodization time and the anodization current density. The second stage provides a continuous development of the alumina film. Total etching process takes 10-20h to get pores of approximately 100 pm lengths. 

Cosse et al. showed that EF decreases as the thickness of anodized Al-0.5%Cu films increases from 3 to 10 J.m.32 Kikuchi et al. reported that EMM of Al specimens resulted in the hemispherical 20-pm-deep microgrooves.40 In this case, porous-type anodization of patterned Al substrates was isotropic. These results suggest that localized anodization becomes isotropic as the anodization process proceeds. These conclusions are consistent with those obtained with other EMM methods, which indicate that EF decreases as the depth of metal removal increases.13,17... 

In order to evaluate EF, one has to consider the dimensions of features undergoing porous-type anodization, which are typically 1-100 pm wide. Data reported in literature suggest that EF decreases when the width of unmasked areas decreases. For example, Renshaw showed the hemispherical cavities of porous AI2O3 formed by porous-type anodization through defects in the nonporous surface oxide films.41 Brevnov et al. reported the radial propagation of pores initiated at the anodization mask defects, which results in... 

Ma, H., Pedel, j., Fife, P. Johnson, W. P. 2009 Hemispheres-in-cell geometry to predict colloid deposition in porous media. Environmental Science and Technology 43, 8573-8579. 

P. Cheng, Natural Convection Porous Medium External Flows, in Natural Convection Fundamentals and Applications, S. Kakac, W. Aung, and R. Viskanta eds., pp. 475-513, Hemisphere Publishing, Washington, DC, Springer-Verlag, Berlin, 1985. 

Brajuskovic, Matovic, and Afgan [84] and Brajuskovic, and Afgan [85] describe a blow-off heat flux sensor that uses gas flowing through a porous sintered metal disc to measure hemispherical radiation heat flux in a dirty environment that includes high particulate loads. The gas acts to blow off fhe boundary layer at the surface. It also cools the instrument, prevents fouling of the porous... 

Dostie, M., J.-N. Seguin, D. Maure, Q.-A. Ton-That, and R. Chatigny, 1989. Preliminary measurements on the drying of thick porous materials hy comhination of intermittent infrared and continuous convection heating. In Drying 89, A.S. Mujumdar and M.A. Roques (Eds.), Hemisphere, New York. 

Silveston, P.L., Reaction with porous catalysts—effectiveness factors, in A. Gianetto and P.L. Sil-veston (Eds), Multiphase Chemical Reactors, Hemisphere Pubhshing Corporation, Washington, DC, 1986. 

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