Papers by Keyword: Specific Volume

Abstract: The features of the dependence of the dielectric constant and the specific volume resistance of the composite "80 wt. % SKI-3 + 20 % wt. % LDPE" from the content of nanosized filler particles - aluminum and black carbon. The use of modern methods for studying macroscopic properties and electron microscopy made it possible to study the structure and morphology of the supramolecular formations of the composite. Models and possible physical mechanisms leading to extreme changes in εʹ and ρ_V at low concentrations of nanoparticles are presented.

Abstract: The porous structure of copper-cadmium oxide system produced by electrochemical synthesis using alternating current in ammonium chloride solutions with concentrations of 3 and 25 wt% was studied. It was shown that the composition of electrolysis products is represented by oxides of copper (I) and (II), hydroxides of cadmium; it depends on the current density and the solution concentration. The products of joint electrochemical oxidation of copper and cadmium obtained in ammonium chloride solution with concentrations of 3 and 25 wt% and current densities of 1 and 3 A/cm² are characterized by mesoporous structure.

Abstract: The development of high performance products at lowest possible product development-time and costs is the demand of the plastics industry today. A successful use of process simulation to describe the behavior of complex structures and to minimize the technical and economic risks for companies requires application and process-relevant material data.The pvT-behavior of polymers is an essential parameter for process simulations. Especially the dependence of the specific volume of pressure and temperature [1, 2] under process conditions is not mapped to the existing measurement methods.In this study pvT measurements were performed on selected amorphous and semi-crystalline polymers (PP, HDPE, POM, PBT, and ABS) with a Pirouette pvT device, a combination of a dilatometer and Couette rheometer. The specific volume was determined as a function of temperature (25-300°C) and at pressures ranging between 200-1000 bar. On top of that, the influence of the cooling rate was also investigated by pvT measurements performed at cooling rates of 0.1°C/s, 1°C/s and 100°C/s.The coefficients for the 2nd domain Tait pvT-model, which is implemented in the software Autodesk Moldflow, were determined by fitting the experimental pvT data and comparing them with the measured curves. As a result, the semi-crystalline polymers show a shift of the transition temperature to lower temperatures and a reduction in the specific volume in the melt is observed. For validation, in a case study shrinkage results in real were compared with the simulation.

Abstract: High performances and operation with low water consumption are mandatory but not sufficient conditions for the Combined Cycles Units implementation in the terrestrial propulsion systems field. There is another restrictive condition, which refers on the admitted size. That is why a dimensional analysis of the Combined Cycles Units is mandatory. In this view, paper presents the results of the dimensional analysis of a small scale Combined Cycles Unit for terrestrial propulsion, based on a two-pressure-levels Steam Cycle and operating with liquid fuel.

Abstract: Twin-screw extruder is the main equipment for puffed food processing. Corn powder as the main raw material, barrel temperature, screw speed and feed rate of the extruder as the independent variables, specific volume of the extrusion product as the objective function, experiment has been carried out base on factorial design method. How the independent variables influence the objective function has been analyzed. Values of the operating parameters to get optimal specific volume has been gained.