Superspreading on Hydrophobic Substrates: Effect of Glycerol Additive

The spreading of solutions of three trisiloxane surfactants on two hydrophobic substrates, polyethylene and polyvinylidenefluoride, was studied with the addition of 0–40 mass % of glycerol. It was found that all the surfactant solutions spread faster than silicone oil of the same viscosity, confirming the existence of a mechanism which accelerates the spreading of the surfactant solutions. For the non-superspreading surfactant, BT-233, addition of glycerol improved the spreading performance on polyvinylidenefluoride and resulted in a transition from partial to complete wetting on polyethylene. The fastest spreading was observed for BT-233 at a concentration of 2.5 g/L, independent of glycerol content. For the superspreading surfactants, BT-240 and BT-278, the concentration at which the fastest spreading occurs systematically increased with concentration of glycerol on both substrates from 1.25 g/L for solutions in water to 10 g/L for solutions in 40% glycerol/water mixture. Thus, the surfactant equilibration rate (and therefore formation of surface tension gradients) and Marangoni flow are important components of a superspreading mechanism. De-wetting of the solutions containing glycerol, once spread on the substrates, resulted in the formation of circular drop patterns. This is in contrast to the solely aqueous solutions where the spread film shrank due to evaporation, without any visible traces being left behind.

Phosphate Equilibration Rate and Daily Clearance in Patients on CAPD, CCPD and APD

Background Criteria for how to assess removal rate of inorganic phosphorous (iP) in peritoneal dialysis (PD) and whether iP removal differs between different PD modalities are debated. Methods In a cross-sectional study, 73 prevalent patients on continuous ambulatory PD (n = 16), continuous cyclic PD (n = 8) or automated PD (n = 49) with mean age 54 (range, 18–87) years, 46 males, underwent standard peritoneal equilibration test (PET) and 24-hour collection of dialysate with measurements of iP, urea and creatinine in all samples and bags. There were 11 slow, 53 average, and 9 fast transporters. Results D/P ratios for iP and creatinine at 4 h of PET were strongly correlated (ρ = 0.86, p<0.0001). Allocation of patients into slow, average and fast transporters according to D/P ratios for iP and creatinine was essentially similar. Whereas the weekly peritoneal clearance of iP (30.8 ± 16.6 L/wk) was lower than that of creatinine (38.4 ± 14.9 L/wk), clearances were strongly correlated (ρ = 0.89, p<0.0001). The correlation between peritoneal weekly clearance of iP and urea KT/V was however weak (ρ = 0.56, p<0.0001. CAPD patients had higher iP clearance than APD patients, 43.2 ± 14.9 versus 24.7 ± 13.4 L/wk (p<0.05); however, serum iP concentrations did not differ. Conclusions Creatinine is a good surrogate marker for phosphate removal, both as assessed by PET and by 24 hours' clearance, in different PD modalities. Therefore, a separate PET scale for phosphate may not be needed. iP removal was greater with CAPD than APD but serum phosphate levels did not differ.

The Effect of Nuclear Elastic Scattering on Temperature Equilibration Rate of Ions in Fusion Plasma

A plasma with two different particle types and at different temperatures has been considered, so that each type of ion with Maxwell-Boltzmann distribution function is in temperature equilibrium with itself. Using the extracted nuclear elastic scattering differential cross-section from experimental data, solving the Boltzmann equation, and also taking into account the mobility of the background particles, temperature equilibration rate between two different ions in a fusion plasma is calculated. The results show that, at higher temperature differences, effect of nuclear elastic scattering is more important in calculating the temperature equilibration rate. The obtained expressions have general form so that they are applicable to each type of particle for background (b) and each type for projectile (p). In this paper, for example, an equimolar Deuterium-Hydrogen plasma with densityn=5×1025 cm−3is chosen in which the deuteron is the background particle with temperature (also electron temperature)Tb=1 keV (usual conditions for a fusion plasma at the ignition instant) and the proton is the projectile with temperatureTp>Tb. These calculations, particularly, are very important for ion fast ignition in inertial confinement fusion concept.