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81.
82.
The paper demonstrates a specific power-series-expansion technique to solve approximately the two-dimensional wave equation. As solving functions (Trefftz functions) so-called wave polynomials are used. The presented method is useful for a finite body of certain shape geometry. Recurrent formulas for the wave polynomials and their derivatives are obtained in the Cartesian and polar coordinate system. The accuracy of the method is discussed and some examples are shown. 相似文献
83.
84.
Ana C.F. Ribeiro Susana M.N. Simões Victor M.M. Lobo Artur J.M. Valente M.A. Esteso 《Food chemistry》2010
A Taylor dispersion method is used to measure ternary mutual diffusion coefficients (D11, D22, D12 and D21) for aqueous solutions of CuCl2 (1) + caffeine (2) + H2O-(3) at 25 °C and 37 °C at carrier concentrations from (0.000 to 0.020 mol dm−3), for each solute, respectively. The results are compared with these obtained for the binary systems, that is, CuCl2 (1) + H2O (2) and caffeine (1) + H2O (2), also reported here. From these data it is possible to make conclusions about the influence of the caffeine solutes in diffusion of copper chloride. 相似文献
85.
Artur Suchan Joanna Nackiewicz Zbigniew Hnatejko Witold Waclawek Stefan Lis 《Dyes and Pigments》2009,80(2):239-244
The association of zinc octacarboxyphthalocyanine, was studied using UV–vis absorption and fluorescence emission spectroscopy; the effects of dye concentration, pH and solvents on spectra were discussed. Calculations showed that the dye dimerized in aqueous solutions ranging from 5.0 × 10?7 to 5.0 × 10?5 mol/dm3, at 25 °C. The dimerization constant of 106 dm3/mol and the spectral Q band shift of 1185 cm?1 imparted by dimerization indicated strong π–π interactions between phthalocyanine molecules. Red S1 fluorescence of the dye monomer was observed in various solutions which was quenched owing to molecular association and other factors. The strong influence of pH on both aggregation and fluorescence was discussed. At pH < 5.0, only dye aggregates were present in solution; monomers appeared at pH ≥ 5.0 and, in alkaline solution, only the monomeric anions of phthalocyanine existed. The spectral absorption and emission data for the dye in binary solvents revealed that at concentrations ranging from 0.5 × 10?5 to 1.0 × 10?5 mol/dm3, the dye can be used in photosensitised oxidation reactions. 相似文献
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87.
Dziedzic Krzysztof Górecka Danuta Szwengiel Artur Michniewicz Jan Drożdżyńska Agnieszka Walkowiak Jarosław 《Food science and biotechnology》2019,28(3):649-655
Food Science and Biotechnology - The tomato pomace obtained during processing as a residue of tomato processing from large industry. The interactions between tomato pomace and fecal bacteria, bile... 相似文献
88.
Kaczyński Łukasz K. Cais-Sokolińska Dorota Szwengiel Artur 《Food science and biotechnology》2019,28(5):1529-1534
Food Science and Biotechnology - The aim of this work was the analysis of galactooligosaccharides (GOS) formation in a model mixture of goat’s milk and its permeate from microfiltration and... 相似文献
89.
Joanna Mastalska‐Popawska Piotr Izak ukasz Wjcik Agata Stempkowska Zuzanna Gral Artur T. Krzyak Iwona Habina 《Polymer Engineering and Science》2019,59(6):1279-1287
Transparent and intumescent polymer‐silicate hydrogels were synthesized by free‐radical polymerization, in the presence of the redox initiators system (potassium persulphate/sodium thiosulphate) and cross‐linking monomer (N,N′‐methylenebisacrylamide). Hydrogels obtained in such a manner were rheologically tested and it was found that the same sample with a different sodium acrylate concentration polymerized faster when its content was lower. The spectroscopic and thermal analysis proved that the polymer combines with sodium silicate by hydrogen bonds and during thermal degradation only small polymer fragments and water molecules were released. NMR studies have shown that the content of water glass causes shorter relaxation times. Conducted fire tests showed that glass panes systems filled with the tested hydrogels meet the relevant construction standards and what is their big advantage, a thin 1 mm layer of polymer‐silicate gel is sufficient for this purpose. We believe that these results will contribute to the development of intumescent hydrogels with enhanced fire‐retardant properties. POLYM. ENG. SCI., 59:1279–1287 2019. © 2019 Society of Plastics Engineers 相似文献
90.
Evaluation of apple texture with contact acoustic emission detector: A study on performance of calibration models 总被引:1,自引:0,他引:1
Artur Zdunek Justyna CybulskaDorota Konopacka Krzysztof Rutkowski 《Journal of food engineering》2011,106(1):80-87
Performance of calibration models for evaluation of apples sensory texture with contact acoustic emission detector (CAED) was studied. For model evaluation and testing, 2500 apples of 19 cultivars were harvested over two seasons. Apples were stored at normal atmosphere (NA), controlled atmosphere (CA) for different periods or were treated with 1-methylcyclopropene (1-MCP) in order to obtain a high variability of texture and fruit maturity. Apples were tested simultaneously in two distinct laboratories. The models were created and validated on averaged values from 10 fruits using simple linear regression, multiple linear regression (MLR) and principal component regression (PCR). Performance statistics of the models were expressed in terms of determination coefficient (R2), root mean square errors of cross validation (RMSECV) or prediction (RMSEP) and ratio of prediction to deviation (RPD). Firmness and total acoustic emission counts were predictors of sensory texture in the models. MLR and PCR models show better performance for prediction of sensory data than simple linear regression models however PCR models show the best results among models tested in this study. Common PCR models for several cultivars allow for successful prediction of hardness (RPD > 2.0), crispness and overall texture (1.5 < RPD < 2.0). The single-cultivar PCR models, constructed on data sets containing 26-39 averaged values, reveal significantly better performance (RPD > 2.0 for most of the cases) than the common PCR models for many varieties. 相似文献