The high sensitivity of the morphology and final properties of co-continuous polymer blends to thermal annealing has motivated many researchers to study the evolution of their morphology during thermal annealing process. In this work, phase coarsening of a low interfacial tension polylactic acid/polycaprolactone blend and a medium interfacial tension polylactic acid/polyethylene blend during quiescent annealing was studied in detail. To this aim, characteristic length scale of the microstructure of the polymer blends was determined at different annealing times. It was found that the phase size in both blends increased linearly by time at the early stage of the annealing and then the phase coarsening rate gradually decreased at longer times. Finally, the phase size of the blends approached a finite size. The mechanisms involved in the observed phase coarsening behavior were discussed in detail. Linear and exponential phase coarsening models in the literature could not explain the observed phase coarsening behavior in the studied blends. A new empirical model was presented which showed a very good agreement with both the obtained results in this work and the previous experimental data in the literature. The obtained results indicate the significant potential of the new model in analyzing phase coarsening behavior of co-continuous polymer blends.
In 37 patients of nephrotic syndrome, serum protein levels, protein fractions and urinary levels of proteins and their fractions were determined. The findings of serum levels of proteins and their fractions were compared with an equal number of age and sex matched controls. Twenty three patients showed selective and 14 non-selective proteinuria. Most of the patients with selective proteinuria showed good response to steroids therapy while those with non-selective proteinuria did not respond. 相似文献
We consider the problem of technical retrofitting of gas-and-oil fired steam-turbine cogeneration stations by converting them into combined-cycle plants as a component of the strategic development of Russia’s electric power industry. The initial statements, methodology, and results obtained from solving the problem are described. 相似文献
Lentils (Lens culinaris L.) are an important protein and carbohydrate food, rich in essential dietary components and trace elements. Selenium (Se) is an essential micronutrient for human health. For adults, 55 μg of daily Se intake is recommended for better health and cancer prevention. Millions of people around the world have Se-deficient diets and biofortification may be an effective solution. The total Se concentration of lentils grown in six major lentil-producing countries were analysed to determine the potential for Se biofortification in these regions. The highest Se concentrations based on location means were found in lentils from Nepal (180 μg/kg) and southern Australia (148 μg/kg) while the lowest were those from Syria (22 μg/kg), Morocco (28 μg/kg), northwestern USA (26 μg/kg), and Turkey (47 μg/kg). Significant location effects within a country were observed for Nepal and Australia. All values were lower than previous published data for Saskatchewan grown lentils (425–672 μg/kg). Lentils originating from Australia, Nepal, or Canada could be considered good sources of Se, as consumption of 50 g would provide 13–61% of the recommended dietary allowance (RDA). Our findings indicate lentil may be appropriate as a target crop for Se biofortification and investigated as a food-based solution for populations with Se deficiencies. 相似文献
The ball and plate system is an inherently nonlinear under actuated benchmark system used for validating the performance ofvarious control schemes. A mathematical model depicting the dynamics close to that of the system is very much required forsuch a test bed. In this correspondence, the complete nonlinear model, a simplified nonlinear model, and a linearized modelof the ball and plate system are developed. The system comprises a ball and plate mechanism and a rotary servo unit. The balland plate mechanism is modelled using the Euler–Lagrange method, whereas the rotary servo subsystem is modelled fromthe first principles. The nonlinear model of the combined system is developed by including the dynamics of the servo motorwith gear and rolling resistance between the ball and the plate. The simplified nonlinear model of the system is obtained withsuitable assumptions. The model is linearized around the operating point using the Jacobian. The validity of the developedmodels is investigated through correlation function analysis. The open-loop response of the three models, viz., nonlinear,simplified nonlinear, and linearized models, is analyzed in the MATLAB/Simulink platform. Since the open-loop system isunstable, the experimental validation of the model is performed with a double-loop PSO (particle swarm optimization) PIDcontrol scheme. 相似文献
The expediency of reducing steelmaking slags to obtain metallic and oxide phases for use in metallurgy and construction is studied experimentally. Slag from the tailings at Zlatoust Metallurgical Plant is investigated. Experiments are conducted on the reduction of slag samples by carbon. The composition of the experimental samples is determined by X-ray spectral microanalysis. Experimental and theoretical data indicate that 20% (or even more) of the initial slag mass may be converted to metal by reduction. Practically complete reduction of the iron in the slag is possible. Significant proportions of the chromium, nickel, manganese, and other valuable components may pass to the metallic phase. Reduction of the liquid slag is expedient at 1500°C or more, so as to extract the metals more completely and form a consolidated metal phase. Preliminary solid-phase reduction of the slag at 1100–1200°C is found to be expedient. This process converts much of the iron present as oxides in the slag to a form susceptible to magnetic separation. Subsequent magnetic separation allows the fraction with an elevated content of valuable metals to be extracted from the oxide phase, which has a low metal content. The oxide fraction may be used in construction materials. In the design of systems based on these principles, utilization of the large quantities of carbon monoxide and metal vapor in the gas phase is recommended. One possibility is to use the carbon monoxide for preliminary solid-phase reduction of the slag. This research permits the development of an efficient system for processing slag tailings. 相似文献
Several new mathematical methods for processing experimental data that can be used in chemical engineering and fluid dynamics are proposed. Direct (explicit and implicit), functional, and combined methods for testing empirical formulas for applicability are discussed. It is shown that for generality purposes it is reasonable to process the final results of experimental studies using special generalized variables, which are invariant under scaling and translation transformations. These variables can be used for testing several empirical formulas at the same time. The proposed methods can be successfully used for processing numerically computed results in order to obtain approximate formulas in any field of natural sciences. 相似文献
A concept and an approach based on this concept for constructing kinetic models of binary aggregation that take into account the impact of the age of clusters of any order on their aggregation activity have been proposed. The classical Smoluchowski and Becker–Döring models have been modified. 相似文献