Volume fraction silica

The moist cells were suspended in 750 parts of volume of ethanol and extracted by warming at 60°C for 1 hour. A total of 3 extractions were carried out in a similar manner and the extracts were pooled, diluted with water and further extracted three times with 1,000 parts of volume portions of n-hexane. The n-hexane layer was concentrated to dryness under reduced pressure to recover 4.12 parts of a yellow oil. This oily residue was dissolved in 6 parts by volume of benzene and passed through a column (500 parts by volume capacity) packed with Floridil (100 to 200 meshes). Elution was carried out using benzene and the eluate was collected in 10 parts by volume fractions. Each fraction was analyzed by thin-layer chromatography and color reaction and the fractions rich in ubiquinone-10 were pooled and concentrated under reduced pressure. By this procedure was obtained 0.562 part of a yellow oil. This product was dissolved in 5 parts by volume of chloroform, coated onto a thin layer plate of silica gel GF254 (silica gel with calcium sulfate) and developed with benzene. The fractions corresponding to ubiquinone-10 were extracted, whereby 0.054 part of a yellow oil was obtained. This oil was dissolved in 10 parts by volume of ethanol and allowed to cool, whereupon 0.029 part of yellow crystals of ubiquinone-10 were obtained, its melting point 4B°to 50°C. 

Figure 7 also shows the plots of (tan8)//(tan8)g versus volume fraction of the filler (0) at Tg and T. Here / stands for the silica filled system and g denotes the gum or unfilled system. The results could be fitted into the following relations [27] ... 

FIGURE 3.24 Plots of volume fraction of the filled rubber in the swollen gel (Vrf) against aging temperature for acrylic rubber (ACM)-silica and epoxidized natural rubber (ENR)-silica hybrid nanocomposites. (From Bandyopadhyay, A. and Bhowmick, A.K., Plastic Rubber Comp. Macromol. Eng., 35, 210, 2006. Courtesy of Money Publishers.)... 

Figure 6 Comparison of the contrast with SANS and SAXS. Typical values of the SLD (cm 2) for SANS and of the electron densities (e /nm3) for SAXS inside the core, shell and solvent are given. The volume fractions inside the shell are estimated for PEO) = water) = 0.5 without silica species and PEO) = Si02) = 0.25 and water) = 0.5...

Figures 3 and 4 give displacement isotherms of PVP adsorbed on pyrogenic silica. The polymer surface excess is plotted versus the volume fraction of displacer < >d. Results in Figure 3 are for water as the solvent and in Figure 4 for dioxane as the solvent. Various displacers were used, as indicated in the figures. One of the displacers was N-ethyl pyrrolidone (NEP), which can be considered as the monomer of PVP. From the isotherm in dioxane, it was found that In = 0.14. The aqueous system shows strong...

The adsorption of block and random copolymers of styrene and methyl methacrylate on to silica from their solutions in carbon tetrachloride/n-heptane, and the resulting dispersion stability, has been investigated. Theta-conditions for the homopolymers and analogous critical non-solvent volume fractions for random copolymers were determined by cloud-point titration. The adsorption of block copolymers varied steadily with the non-solvent content, whilst that of the random copolymers became progressively more dependent on solvent quality only as theta-conditions and phase separation were approached. 

In the absence of polymer the sediment volume of silica depends on the non-solvent fraction of the medium as shown in Figure 6. The sediment volume assessment of steric stabilization behavior of the copolymers is illustrated in Figures 7a to 7c. At low styrene contents, both the random and block copolymers show a steady increase in sediment volume as the non-solvent content is raised up to the phase separation value. With polystyrene and random copolymers of high styrene content, the sediment volume stays largely constant with alteration in the non-solvent fraction until the theta-point is approached and then continues to become larger as the limit of solubility is reached. In Figure 7b only the data points of RC 86 are shown, RC 94 giving almost identical values. 

Block copolymers at high styrene contents behave similarly, with no break around the micellar region. Two of the block copolymers are shown separately in Figure 7c. The low M.W. BC 90 moves from an apparently adequate stabilization in CCI4 to a new level of modest protection at higher CyH g volume fractions. The block polymer of 42% styrene gives a hint of a discontinuity at the non-solvent content for micelle formation, but thereafter stabilizes the silica until the conditions approach those for phase separation. 

From the above data, it would appear that methane densities in pores with carbon surfaces are higher than those of other materials. In the previous section it was pointed out that to maximize natural gas or methane storage, it is necessary to maximize micropore volume, not per unit mass of adsorbent, but per unit volume of storage vessel. Moreover, a porous carbon filled vessel will store and deliver more methane than a vessel filled with a silica based or polymer adsorbent which has an equivalent micropore volume fraction of the storage vessel. 

Volume changes, by vitreous silica, 22 438 Volume flux, of droplets, 23 187 Volume fraction, in filtration, 11 328 Volume fraction calculation, in equivalent box model, 20 345—346 Volume mean diameter, 23 186 Volume of activation, 13 407-408... 

Figure 6.5 Plot of the apparent storage and loss moduli as a function of strain for volume fractions of dispersions of silica particles (a — I50nm, c — 10 3 M)...

Figure 20. Electro-osmotic drag coefficients of diverse membranes based on perfluorinated polymers (Dow - and Nafion/silica composites ) and polyarylenes (S—PEK/ PSU blends, ionically cross-linked S—PEK/PBP ), as a function of the solvent (water/methanol) volume fraction Xy (see text for references). Lines represent data for Nafion and S—PEK (given for comparison) for data points, see Figure 15. Dashed lines correspond to the maximum possible electro-osmotic drag coefficients for water and methanol, as indicated (see text).

The Lee and Gieseke model (8) for predicting aerosol collection on packed beds assumes that the volume fraction, or solidity, of the packed bed approaches 5/8, and applies to the collection by the packed bed only. Since the silica gel collection tube has a volume fraction of one-half or less, and since the greater percentage of the aerosol is collected on the initial glass wool plug, the model is not applicable to our sampler design. 

Salamone and Newman (SI) recently studied heat transfer to suspensions of copper, carbon, silica, and chalk in water over the concentration range of 2.75 to 11.0% solids by weight. These authors calculated effective thermal conductivities from the heat transfer data and reached conclusions which not only contradicted Eqs. (35) and (36), but also indicated a large effect of particle size. However, if one compares the conductivities of their suspensions at a constant volume fraction of solids, the assumed importance of particle size is no longer present. It should also be noted that their calculational procedure was a difficult one in that it placed all undefined errors present in the heat transfer data into the thermal conductivity term. For example, six of the seven-... 

Gillespie and Wiley used a cone-and-plate viscometer to measure F/A versus dv/dx for dispersions of silica and cross-linked polystyrene in dioctyl phthalate. At a volume fraction of 0.35 for both solids, the following results were obtained ... 

Figure 8.5 Plot of volume fraction ratio Vro/Vrf characterizing the swelling of an unfilled PDMS network relative to that of a filled PDMS network, against filler loading expressed as volume ratio of filler to PDMS is the volume fraction of filler).40 Types of filler were silica-titania mixed oxides ( ), silica (O), and titania (A).

Figure 21.4 Influence of nanoparticle size on silica-type mesostructuie. (a, b) TEM micrographs showing mesostructuies with a nanoparticle volume fraction

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