An oscillating capillary rheometer was used to investigate the effects of xanthan deacetylation on the viscoelastic properties and intrinsic viscosity of xanthan and guar mixtures in dilute aqueous solutions. Deacetylated xanthan exhibited a stronger synergistic interaction with guar than native xanthan did due to the destabilized helical structure and increased chain flexibility of the deacety...

The viscosity of a suspension of swimming bacteria is investigated analytically and numerically. We propose a simple model that allows for efficient computation for a large number of bacteria. Our calculations show that long-range hydrodynamic interactions, intrinsic to self-locomoting objects in a viscous fluid, result in a dramatic reduction of the effective viscosity. In agreement with exper...

oxygen delignified kraft pulp from eucalyptus (e. urophylla × e. grandis) was catalytically pretreated in aerobic condition using ammonium persulfate in present of catalists like cupric acetate and/or cobalt acetate in acetic acid-water solution, i. e. s2o82--cu2+, s2o82--co2+ and s2o82--(cu2++co2+). final bleached pulp after pretreatment with the three catalytic systems showed higher delignifi...

nowdays, production of high quality engine oils is one of the worries of our country’s engine oil industry. in this study, the behavior of four commercial polymers used in nation motor oil industry in obtaining the best viscosity index improver was investigated. in this regard, viscometric behavior, shear stability and polymers’ performance for engine cranking were compared at low temperature. ...

We tested the hypothesis that solvent viscosity affects translocation of rhodamine phalloidin-labeled F-actin by rabbit skeletal heavy meromyosin (HMM). When viscosity was increased using either glycerol, fructose, sucrose, or dextran (1.5, 6.0, or 15-20 kDa mol mass), there was little or no effect on the fraction of moving filaments, whereas sliding speed decreased in inverse proportion to vis...

Gelatin is a natural polymer widely used in pharmaceutical, cosmetic, photographic, and food industries. It is obtained by denaturation and partial hydrolysis of fibrous collagen. Collagen is the most abundant structural protein of animals and by far the main organic component of skin and bone of vertebrates. However, collagen is standing for a family of proteins with 21 different types of amin...

The problem of calculating the electric polarizability tensor alpha(e) of objects of arbitrary shape has been reformulated in terms of path integration and implemented computationally. The method simultaneously yields the electrostatic capacity C and the equilibrium charge density. These functionals of particle shape are important in many materials science applications, including the conductivi...

While the basic chemical structure of a synthetic high polymer is usually well understood, many physical properties depend on such characteristics as chain length, degree of chain branching, and molecular weight, which are not easy to specify exactly in terms of a molecular formula. Moreover, the macromolecules in a given sample are seldom uniform in chain length or molecular weight (which for ...