Growth in the velocity of mass transfer through the CMX membrane during its aging by operation in intense current regimes

One of the causes for the aging of membranes during their operation in electrodialysis (ED) of solutions is irreversible chemical changes in the ion exchange or reinforcement polymer due to interaction of H⁺ and OH⁻ ions (present in feed solutions or generated in the membrane system under intense current modes) with the matrix or fixed groups in the surface layer of the membranes. The reduction in current efficiency and an increase in energy consumption in the process of electrodialysis are usual consequences of these changes. It has been shown that the degradation of the ion-exchange polymer on the surface of the CMX membrane during its operation in intense current regimes results in the hydrophobization of the membrane surface, which, in turn, causes enhancement of electroconvection. As a result, the limiting current and the mass transfer coefficient of salt ions increase during membrane operation. In the case of desalination of dilute solutions, this growth can reach 50–70% in comparison with the fresh membrane.     

Effect of mechanical activation of Ni-Fe-NaCl powder charges in liquid media on the structure and properties of high-porosity materials

It has been established that the time of activation in liquid media (LMA) and the iron content of the charge are of decisive importance in determining the porosity of sintered materials. The authors determined the critical time of treatment for a charge inside a mill (1.5 ksec), this length of treatment ensuring that the transition from LMA to mechanical activation takes place. They also determined the optimum values for the process parameters, making it possible to obtain sintered high-porosity materials (HPM) with the porosity P = 64%.     

Shape of Diffusive Interface Under Periodic Excitations at Different Gravity Levels

This work discusses the role of gravity on the shape of interfacial waves between miscible liquids under horizontal vibrations. A big difference in the shape of an interfacial pattern has recently been observed in low-gravity experiments when compared to earth-based one. The evolution of an interfacial pattern from zero to normal gravity is discussed in the context of non-linear simulations in a confined system. The development of vibration-induced frozen waves with gravity is characterized by three distinct regimes that are associated with the wave height and the angle at the vertices of saw-tooth shape of the interface.     

Nitrogen-Induced Changes in Phenolics of Vaccinium myrtillus—Implications for Interaction with a Parasitic Fungus

The effects of nitrogen (N) fertilization on the phenolic status of Vaccinium myrtillus leaves were studied to assess whether N amendment affects the potentially defensive phenolic metabolites in a way that could have consequences for the interaction with a parasitic fungus (Valdensia heterodoxa). Healthy (symptomless) and V. heterodoxa-infected leaves were collected from plants grown in the understorey of a boreal coniferous forest, where they received no additional N or either a moderate or a high dose of N fertilizer. Leaf samples were taken during a single growth season and analyzed for individual phenolics using HPLC. The effect of a moderate N dose on the concentration and content of phenolics was in most cases nonsignificant. In contrast, the high N dose resulted in pronounced effects. In healthy leaves, N fertilization reduced concentration of three of five individual phenolics. Moreover, fertilization with high dose of N accompanied by infection by V. heterodoxa often increased the concentration and content of phenolics as compared to unfertilized plants. Addition of N had no significant effect on the growth of the analyzed V. myrtillus leaves, and the N-induced variation in phenolic levels seemed to be due to changed rate of their production. The concentration and content of phenolic metabolites in healthy leaves collected from unfertilized plots fluctuated compound-specifically during the growth season, and the phenolic responses to N and infection showed temporal and compound-specific variations.     

Sorption equilibria and diffusion of toluene,methanol, and cyclohexane in/through elastomers

Molecular transport of toluene, methanol, and cyclohexane and their mixtures in Chemraz 505 elastomer has been investigated using gravimetric techniques for short and long time exposure in these solvents. The sorption–desorption results have been used to calculate the diffusion coefficients by solving Fick's equation under appropriate boundary conditions. The dependence of sorption, desorption, diffusion, and permeation on temperature and composition changes was also studied. The results are discussed in terms of possible interactions between Chemraz 505 polymer and the solvent molecules. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43449.     

Investigation of the Process of Stability Loss for Smooth Thin-Walled Cylindrical Shells under the Local Action of a Radiation Pulse

It is shown that, under the action of a short-term pulse of external pressure caused by laser radiation, a shell suffers elastic deformation in the course of interaction with the pulse according to the short-wave form on the boundary of the region of loading. When the pulse action is terminated, the shell continues its motion, which is not axially symmetric. As soon as the limiting displacements are attained, the global stability loss is observed. The form of wave formation of the global stability loss in the circumferential direction is determined by the size of the region of loading.     

Secondary infection with hepatitis A in Rhesus monkeys after experimental inoculation

Guanoxabenz (1-(2,6-dichlorobenzylidene-amino)-3-hydroxyguanidine) and guanabenz (1-(2,6-dichlorobenzylidene-amino)-3-guanidine) are both known as centrally active antihypertensive drugs. We have previously shown that enzymatic activity in the rat spleen can induce N-reduction of guanoxabenz, leading to high affinity alpha 2-adrenoceptor binding, due to the formation of the alpha 2-adrenoceptor active drug, guanabenz. The spleen activity appears to reside in xanthine oxidase as it is activated by xanthine and blocked by allopurinol. We report that high affinity guanoxabenz binding is also induced in rat brain membranes after addition of NADH or NADPH cofactors. However, the brain process was clearly different from that of the spleen, as the formation of high affinity binding in the brain was not blocked by allopurinol. Moreover the NADH/NADPH activated mechanism of the brain membranes was not blocked by carbon monoxide and SKF525A, thus the activity appears not to reside in cytochrome P450 enzymes. Instead the activity was blocked by menadione and dicumarol. We conclude that the rat cerebral cortex contains an enzymatic activity that may activate guanoxabenz leading to formation of a metabolite showing high affinity for alpha 2-adrenoceptors. We also conclude that the rat brain activity is clearly distinct from that of the rat spleen.     

Diffusion and Soret in Ternary Mixtures. Preparation of the DCMIX2 Experiment on the ISS

We report on ground-based studies in course of preparation of the experiment DCMIX₂ (Diffusion coefficient in mixtures) to be performed on the International Space Station (ISS). In microgravity experiment the diffusion and thermodiffusion coefficients will be measured at six points with different compositions of the ternary mixture Toluene-Methanol-Cyclohexane. This mixture attracts attention of the researchers, as it has a miscibility gap and presumably large region with negative Soret coefficients. By using Optical Digital Interferometry we have measured the variations of refractive index Δn in the full parameter space of concentrations. The regions of stable and unstable behavior of system were determined from the time-dependent behavior of Δn. The system is hydrodynamically unstable in a wide region of compositions where Soret measurement should be done in microgravity. We present the results of the study of the compatibility of this mixture with often used sealing materials:Viton (R), Chemraz (R) and different types of Kalrez. To facilitate the expected theoretical studies we have measured density and thermal expansion in the points of the interest.