Ultrasonic crystallizer of CuSO4 solution: Engineering simulation

Ultrasound crystallizer of copper sulfate solution based on creating the solidification front with the aid of a gradient of temperature, which was exposed to ultrasonic waves with use of a magnetostrictive transducer, was proposed. The algorithm for the calculation of critical process parameters of the crystallization was developed jointly using the differential transport equations of momentum, mass, energy, sound waves, and a method of similarity and dimensional analysis.     

Shock waves in saturated thermoelastic porous media

The objective of this paper is to develop and present the macroscopic motion equations for the fluid and the solid matrix, in the case of a saturated porous medium, in the form of coupled, nonlinear wave equations for the fluid and solid velocities. The nonlinearity in the equations enables the generation of shock waves. The complete set of equations required for determining phase velocities in the case of a thermoelastic solid matrix, includes also the energy balance equation for the porous medium as a whole, as well as mass balance equations for the two phase. In the special case of a rigid solid matrix, the wave after an abrupt change in pressure propagates only through the fluid.     

Stress-biased rearrangements and preyield behavior in glasses

On the basis of a physical picture of a glass as a mosaic of mesoscopic clusters differing in their yield characteristics, we propose a model for the preyield behavior in glassy materials; the model describes the stress-strain relationship at different strain rates in terms of one reduced variable. A test using experimental data for polycarbonate materials at different rates and temperatures appears favorable for the model. The model may be used to interpolate and extrapolate limited experimental data, and also provides a practical means to assess dynamic heterogeneities within polymeric glasses. When applied at different temperatures, the model gives insight into the dependence of the excitation energies on temperature (glassformer fragility) in the glassy state.     

WST11, a novel water-soluble bacteriochlorophyll derivative; cellular uptake, pharmacokinetics, biodistribution and vascular-targeted photodynamic activity using melanoma tumors as a model

WST11 is a novel negatively charged water-soluble palladium-bacteriochlorophyll derivative that was developed for vascular-targeted photodynamic therapy (VTP) in our laboratory. The in vitro results suggest that WST11 cellular uptake, clearance and phototoxicity are mediated by serum albumin trafficking. In vivo, WST11 was found to clear rapidly from the circulation (t1/2=1.65 min) after intravenous bolus injection in the mouse, whereas a longer clearance time (t1/2=7.5 min) was noted in rats after 20 min of infusion. The biodistribution of WST11 in mouse tissues indicates hepatic clearance (t1/2=20 min), with minor (kidney, lung and spleen) or no intermediary accumulation in other tissues. As soon as 1 h after injection, WST11 had nearly cleared from the body of the mouse, except for a temporal accumulation in the lungs from which it cleared within 40 min. On the basis of these results, we set the VTP protocol for a short illumination period (5 min), delivered immediately after WST11 injection. On subjecting M2R melanoma xenografts to WST11-VTP, we achieved 100% tumor flattening at all doses and a 70% cure with 9 mg/kg and a light exposure dose of 100 mW/cm2. These results provide direct evidence that WST11 is an effective agent for VTP and provide guidelines for further development of new candidates.     

Head-on collision between normal shock waves and a rubber-supported plate,a parametric study

The equations governing the flow resulting from a head-on collision between a normal shock wave and a rubber-supported plate are listed. The non-dimensional parameters that may affect the resulting flow are specified and their influence on the post-collision flow and waves is studied numerically. It is shown that changes in: the area-ratio between the gas and the rubber cross-sections, the incident shock wave Mach number and the mass ratio between the rubber and the plate it supports, all have significant effects on the post-collision gas and rubber responses. Changes in the rubber elasticity constant also affect the post-collision flow. The extent of the effect that changes in the above mentioned parameters have on the post-collision flow responses depends upon the loading mode used. Three different modes were studied; uni-axial stress loading, bi-axial stress loading and uni-axial strain loading.This article was processed using Springer-Verlag T_EX Shock Waves macro package 1.0 and the AMS fonts, developed by the American Mathematical Society.     

Hydrodynamics of a centrifugal turbine agitator-pump

Hydrodynamics and agitation energy of viscous fluids was considered in apparatuses with a centrifugal turbine agitator-pump applied in vacuum filtration systems for water softening. Using the Navier-Stokes equations we solved an axisymmetric problem in the variables: pressure-velocity, vorticity-flow function. A flow region behind turbine blades is represented as a pair of symmetrical macrovortices forming vortex tubes with vortex cores and potential flow between them. We determined hydrodynamic parameters such as: a circulation around a contour enclosing the vortices, the drag coefficient and pressure drop when moving blades, coordinates of centers of the macrovortices, radial, tangential, and axial flows and corresponding them mass flows of liquid. We determined a limiting mode of the absence of cavitation in the turbine and calculated energy dissipation and power criteria: parameters used to scale turbine agitators. The obtained data underlay the study of mass transfer in the vacuum filtration system designed to remove the calcium cations from water.     

Drying of granules in vibrating suspended bed: Engineering simulation

Engineering algorithm for simulation and designing of a continuous convective drying apparatus serving for drying heat-stable and heat-labile granules in a vibratory fluidized bed (vibrating, suspended bed) was suggested. The algorithm was based on a joint use of mass and heat balance equations, empirical dependences, and comparison of technological parameters with parameters got by the mathematical simulation of dynamics in the vibratory fluidized bed of variable weight. For example, we suggested a calculation algorithm of technological parameters of drying the heat-stable zeolite granules in the vibrating suspended bed. The results for a unit cost of heat and moisture evaporation standards in 3-stage drying were compared with the same for pneumatic drying apparatus, with devices of the fluidized and vibratory fluidized beds, and with sublimation dryers known in industry.