Apparate

Ohne Zusammenfassung     

Non-Gravitational Effects with Density-Matching in Evaluating the Influence of Sedimentation on Colloidal Coagulation

The method of density matching between the solid and liquid phases is often adopted to effectively eliminate the effect of sedimentation of suspensions in studies on dynamic behaviour of a colloidal system. However, the associated changes in the solvent composition may bring side effects to the properties investigated and therefore might lead to a faulty conclusion if the relevant correction is not made. To illustrate the importance of this side effect, we present an example of the sedimentation influence on the coagulation rate of suspensions of 2μm （diameter） polystyrene. The liquid mixtures, in the proper proportions of water （H2O）, deuterium oxide （D2O） and methanol （MeOH） as the liquid phase, density-matched and unmatched experiments are performed. Besides the influence of viscosity, the presence of methanol in solvent media, used to enhance the sedimentation effect, causes significant changes （reduction） in rapid coagulation rates compared to that in pure water. Without the relevant corrections for those non-gravitational factors it seems that gravitational sedimentation would retard the coagulation. The magnitude of the contribution from the non-gravitational factor is quantitatively determined, making the relevant correction possible. After necessary the influence of the sedimentation on coagulation rates at corrections for all factors, our experiments show that the initial stage of the coagulation is not observable.     

Influence of the nature of a curing agent on the peculiarities of formation of vulcanization networks in polysulfide sealants

The molecular mobility of vulkanizates of liquid thiokols cured with various vulcanizing agents was studied by the NMR method in a wide temperature interval. The influence of the nature of vulcanizing agents and the structure of the forming vulcanization network on the change in the character of molecular mobility in vulcanizates of polysulfide oligomers was established. The correlation of effective (υ_eff) and chemical (υ_ch) densities of vulcanization networks of thiokol sealants with parameters of the NMR spectrum of the latter was found. The influence of the nature of a curing agent on the peculiarities of the formation of vulcanization networks of polysulfide oligomers is discussed.     

A Heterogeneous Photosensitizer Based on Zinc Oxide for Photo Cleaning of Aquatic Media

Doklady Physics - A new composite material based on zinc oxide photosensitized to daylight with an organic dye of the phthalocyanine group has been proposed. The photoactivity of the material...     

Demonstrator of continuous-detonation air-breathing ramjet: Wind tunnel data

First experimental investigations were carried out into the detonation combustion of hydrogen in a demonstrator of an original-design air-breathing ramjet while blowing with an air flow at Mach 4 to 8 in an impulse wind tunnel, and for the first time under these conditions, continuous spin and longitudinal pulsed modes of detonation combustion of hydrogen in an annular combustor were detected.     

New polymer composites based on keratin and polyethylene

New biodegradable composites based on keratin and polyethylene have been produced under shear deformation. It has been demonstrated that the introduction of keratin leads to an increase in elastic modulus and to a decrease in ultimate tensile strength and elongation at break of the compositions. Elongation at break ε_b depends on the keratin dispersity; the highest ε_b values are observed for the compositions containing the smallest keratin particles. It has been shown that the compositions are susceptible to mold fungi; i.e., they are biodegradable.