Layer of Low Density

Suppose a rigid flat surface supports an explosive layer, which is subject to impact by a rigid cylindrical body (of diameter D) with flat base. Fig 6a illustrates impact on a layer of high density, and Fig 6b impact on a layer of low density, for example bulk density. In the latter case, the explosive should be strongly compacted in the impact zone before a significant pressure rise begins. The deformation... 

Fig 6b. Layer of low density (pressing of the material takes place at the beginning of the impact)... 

The fuel particles used in these studies were typical pyrolytic carbon-coated thorium-uranium dicarbide, (Th,U)C2, microspheres. The kernels, — 200/i in diameter, were prepared from Th02, U02, and C and converted to the carbide at temperatures below 2200°C., followed by a spheroidization above the melting point, 2450°-2500°C. The bare kernels were coated with a 30-50fi layer of low density (— 1.0 gram/cm.3) buffer pyrolytic carbon, followed by a 40-70/a layer of high density... 

Besides temperature (Figure 5a), the cold and warm scenarios differ by the structure of the snowpack. In both cases, the snow water equivalent have the same temporal evolution 2 cm at the end of October, 11 cm at the end of January and 15.7 cm in late April. Stratigraphies and heat conductivities are very different. In the cold scenario, depth hoar layers of low densities (0.21 to 0.26 g.cm O alternate with denser windpacks (0.38 to 0.48). Transient layers of fresh snow and of faceted crystals are also present. values range from 0.06 W.m K for aged depth hoar to 0.46 W.m K for dense windpacks. In the warm scenario, two melt-freeze layers (densities 0.40 to 0.55) alternate with hard windpacks (0.34 to 0.41) while layers of fresh snow are sometimes included in the mean monthly stratigraphies, kr values are 0.45 and 0.63 W.m K for the melt-freeze layers and range from 0.36 to 0.48 W.m K for dense windpacks. Recent snow has values around 0.2 W.m lC Overall, the warm snowpack has a greater heat conductivity than the cold one. 

Polyolefine films are the most applicable, in which the high-density polymer layers fulfil the strengthening and barrier functions and a layer of low-density polyolefine contains a Cl [19,28,30]. For instance, in a strengthened multilayer Cortec VCI-126 film the outer layer is formed of LDPE with HOPE strips. The inner inhibited layer is made of LDPE. 

The 6 cm spherical fuel elements of HTR-10 are made of TRISO type coated particles (CP) and graphite matrix. One CP consists of a UO2 kernel with a diameter of 0.5 mm, which is successively coated with layers of low density pyrolytical carbon, inner high density isotropic pyrolytical carbon, silicon carbide and outer high density isotropic pyrolytical carbon, with thicknesses of respectively 90, 40, 35 and 40 pm. About 8,300 coated particles are dispersed in the graphite matrix, which is 5 cm in diameter, to form the fuel zone of a fuel... 

Since I consider sterilisation by irradiation a very suitable method there seems no point in using ethylene oxide which must surely be soluble in this plastic. Ethylene oxide freely penetrates two layers of low density polyethylene 250 micron thick and until proved otherwise, I think one has to accept that it will be very soluble in high density polyethylene. I fail to see how one can be sure of getting out all the ethylene oxide when double wrapped, even with the precautions mentioned in this letter. 

Density gradients to stabilize flow have been employed by Philpot IT> Yin.s. Faraday Soc., 36, 38 (1940)] and Mel [ j. Phys. Chem., 31,559 (1959)]. Mel s Staflo apparatus [J. Phys. Chem., 31, 559 (1959)] has liquid flow in the horizontal direction, with layers of increasing density downward produced by sucrose concentrations increasing to 7.5 percent. The solute mixture to be separated is introduced in one such layer. Operation at low electrolyte concentrations, low voltage gradients, and low flow rates presents no cooling problem. 

Direct fluorination of polymer or polymer membrane surfaces creates a thin layer of partially fluorinated material on the polymer surface. This procedure dramatically changes the permeation rate of gas molecules through polymers. Several publications in collaboration with Professor D. R. Paul62-66 have investigated the gas permeabilities of surface fluorination of low-density polyethylene, polysulfone, poly(4-methyl-1 -pentene), and poly(phenylene oxide) membranes. 

If a solution containing approximately 4 mole percent sodium in ammonia is cooled below -42°C (231 K) a remarkable liquid-liquid phase separation occurs (33, 155). The solution physically separates into two distinct layers—a low-density, bronze metallic phase that floats out on top of a more dense, less concentrated dark-blue phase. The first experimental observation of this striking phenomenon in sodium-ammonia solutions was made by Kraus (109, 110) in 1907 more recent studies have mapped out the phase coexistence curves for a variety of alkali and alkaline earth metals in liquid ammonia, and these are delineated and discussed elsewhere (164). 

Derive an expression for the ratio of the heat conducted through an air layer at low density to that conducted for A = 0. Plot this ratio versus A L for a = 0.9 and air properties evaluated at 35°C. 

Physical-chemical features of WIW emulsions compared to oil-in-water (OIW) and water-in-oil WIO) emulsions are low interfacial tension, interfacial layers of low biopolymer concentration, interfacial adsorption of lipids and high deformability of aqueous dispersed particles. Low interfacial tension in WIW emulsions reflects similar compositions of coexisting phases, where water and the biopolymers are partially cosoluble. The low-density interfacial layer is due to a trend of incompatible biopolymers to have surroundings of the same type. One more feature of WIW emulsions is a great difference in concentration between coexisting phases. This is due to the competition between the biopolymers for space in solution. The competition can be characterized (Figure 3.5) by the angle made by the tie-line with one of the concentration axes. 

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