Dynamics of suspensions of hydrodynamically structured particles: Analytic theory and experiment

We present an easy-to-use analytic toolbox for the calculation of short-time transport properties of concentrated suspensions of spherical colloidal particles with internal hydrodynamic structure, and direct interactions described by a hard-core or soft Hertz pair potential. The considered dynamic properties include self-diffusion and sedimentation coefficients, the wavenumber-dependent diffusion function determined in dynamic scattering experiments, and the high-frequency shear viscosity. The toolbox is based on the hydrodynamic radius model (HRM) wherein the internal particle structure is mapped on a hydrodynamic radius parameter for unchanged direct interactions, and on an existing simulation data base for solvent-permeable and spherical annulus particles. Useful scaling relations for the diffusion function and self-diffusion coefficient, known to be valid for hard-core interaction, are shown to apply also for soft pair potentials. We further discuss extensions of the toolbox to long-time transport properties including the low-shear zero-frequency viscosity and the long-time self-diffusion coefficient. The versatility of the toolbox is demonstrated by the analysis of a previous light scattering study of suspensions of non-ionic PNiPAM microgels [Eckert et al., J. Chem. Phys., 2008, 129, 124902] in which a detailed theoretical analysis of the dynamic data was left as an open task. By the comparison with Hertz potential based calculations, we show that the experimental data are consistently and accurately described using the Verlet-Weis corrected Percus-Yevick structure factor as input, and for a solvent penetration length equal to three percent of the excluded volume radius. This small solvent permeability of the microgel particles has a significant dynamic effect at larger concentrations.Comment: 25 pages, 24 figure

Об инвариантности кинематических базисных матриц планетарных рядов при анализе кинематики трансмиссий транспортных средств

Предложена универсальная матричная методика расчета кинематики планетарных механизмов. Показано, что кинематические матричные системы планетарных механизмов, несмотря на отличие в записи с различными значениями характерных параметров сателлитов, инвариантны по отношению к вектору неизвестных.The universal matrix design procedure of kinematics of planetary mechanisms is offered. It is shown, that kinematics matrix systems of planetary mechanisms, despite of distinction in record with different values of characteristic parameters of satellites, invariance in relation to a vector of unknown persons

Non-reciprocal preference erosion arising from MFN liberalitzation in agriculture: What are the risks?

This paper estimates the risk of preference erosion for non-reciprocal preference recipients in the agricultural sector as a consequence of MFN tariff cuts. It is based on a simulation of a single tariff-cutting scenario. The measure of preference erosion risk is the difference in preference margins enjoyed by individual suppliers to the QUAD (Canada, EU, Japan, United States) markets before and after a MFN tariff reduction, multiplied by the associated trade flow. The paper does not attempt to determine how losses in preference margins translate into trade outcomes, but it does highlight which products and which non-reciprocal preference beneficiaries are the most vulnerable to erosion effects in the major developed country markets. Overall, the paper finds that the risk of preference erosion is small, but some countries are strongly affected in particular product lines (notably sugar and bananas)

Metallocene o-Phenylenebis(phenylphosphido) Chelates of Molybdenum and Tungsten

The reaction of the metallocene dichlorides Cp2MCl2 (Cp = η5-C5H5; M = Mo, W) with equimolar amounts of dilithium-o-phenylenebis(phenylphosphide) 1,2-(LiPPh)2C6H4 yields the five-membered chelate complexes Cp2M[1,2-(PPh)2C6H4] (M = Mo. 1; W, 2). Compounds 1 and 2 are characterized by IR, NMR and mass spectra

Physical and chemical features of hydrophilic microarc biocoatings based on substituted hydroxyapatite

The physical and chemical properties as topography, morphology, chemical composition and wettability of microarc calcium phosphate coatings based on Zn- and Cu- substituted hydroxyapatite on the Ti-40mas.%Nb alloy surface has been investigated. It have been found that calcium phosphate coatings on Ti-40mas.%Nb alloy produced under 200 V have X-ray amorphous state and as consequence high rate of dissolution. The phase composition of the coatings produced under 300 V is presented the following phases: CaHPO4,beta-Ca[2]P[2]O[7], Ca[2]Nb[2]O[7], NbO[2], Nb[2]O[5], TiO[2]. It has been shown that the biocoatings are very hydrophilic