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151.
The process of ozone production in pure oxygen was studied. It was shown how the ozone concentration changes along the discharge gap, both during its generation and decomposition processes. The effect of ozone inlet concentration, power, and gas residence time on ozone concentration was analyzed. It has been shown that concentrated ozone is easily decomposed at very low discharge powers, i.e., when the increase of the average gas temperature in the gap is negligibly small. It was hypothesized that the most intense decomposition takes place in the microdischarge channels, because the process of gas heating in the gap begins inside them. 相似文献
152.
Dominik Mierzwa Justyna Szadzińska Andrzej Pawłowski Reihaneh Pashminehazar Abdolreza Kharaghani 《Drying Technology》2019,37(8):988-1001
This study was conducted to investigate the drying characteristics and quality of raspberries dried in non-stationary conditions. Seven drying programs were carried out, including convective (CV) drying as a reference. The non-stationary-hybrid programs were based on continuous CV drying with intermittent microwave and ultrasound assistance. The Midilli–Kucuk model was used successfully to describe the drying kinetics of raspberry fruits. The comparison between moisture ratio, drying rate, diffusion coefficient, energy consumption, and quality analysis, showed that non-stationary-hybrid drying improves process kinetics and results in less color change, higher anthocyanin retention, and better texture profile analysis characteristics with optimal energy usage than other methods. In addition, the physical and microstructural changes occurred during different drying processes were discussed. 相似文献
153.
Aleksandra Szydłowska-Czerniak Agnieszka Tułodziecka Monika Momot Barbara Stawicka 《Journal of the American Oil Chemists' Society》2019,96(4):405-419
Physicochemical characteristics, antioxidant capacity (AC), and sensory quality of rapeseed oils available on the Polish market were analyzed and compared. The fatty acid composition (saturated fatty acids = 6.91–7.58%, monounsaturated fatty acids = 64.14–66.14%, and polyunsaturated fatty acids = 27.22–30.17%), color (T420 = 54.5–83.8%), amounts of free fatty acids (0.02–0.07%), primary (PV = 0.04–2.04 meq O2 kg−1) and secondary (AV = 1.02–3.21) oxidation products, phosphorus (0.38–1.62 mg kg−1), chlorophyll (0.002–0.068 mg kg−1), and polycyclic aromatic hydrocarbons (Σ4PAH = 0.00–2.50 μg kg−1) in the commercial rapeseed oils meet the requirements of the European Food Regulation and Codex Alimentarius standards. Moreover, total phenolic content (TPC = 40.3–467.9 mg SA kg−1) in the studied oils significantly differs from each other. However, the AC of rapeseed oils was analyzed using the novel iron oxide nanoparticle-based (IONP = 5552.1 − 18,510.2 μmol TE/100 g) method and the modified ferric reducing antioxidant power (FRAP = 55.7–280.3 μmol TE/100 g), cupric reducing AC (CUPRAC = 79.6–784.0 μmol TE/100 g), 2,2-diphenyl-1-picrylhydrazyl (DPPH = 185.7–516.7 μmol TE/100 g), and 2,2′-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS = 465.6–2142.6 μmol TE/100 g) assays. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) were applied for discrimination of the refined rapeseed oils based on fatty acid composition, physicochemical parameters, AC, and sensory properties. 相似文献
154.
155.
Katarzyna Szymczyk Magdalena Szaniawska Konrad Terpiłowski 《Journal of surfactants and detergents》2019,22(5):1163-1174
Measurements of density, speed of sound, and surface tension as well as viscosity of aqueous Kolliphor® ELP (ELP) and Kolliphor® RH 40 (RH40) solutions as well as binary mixtures at different surfactant mole fractions were made at 293 K to investigate their aggregation behavior. The free volume, internal pressure, and molar cohesive energy were calculated and compared to the specific acoustic impedance and intermolecular free length to obtain qualitative information about the character of interactions between the surfactant molecules in the mixture through the water phase. 相似文献
156.
157.
An Al 2024 (AA2024-T351) alloy having less Mg and a higher proportion of Cu to Mg (mass ratio ≈3.7) has been characterised to provide input data for microscale and macroscale corrosion models. The Al 2024 alloy microstructure has a significant presence of nanoscale dispersoid and microscale AlCuFeMnSi (2nd phase) intermetallic particles, but a smaller population of microscale S phase (Al2CuMg) and θ phase (Al2Cu) intermetallic particles. Microscale electrochemical data show that pitting potential (SCE) values for 2nd phase, S phase, or matrix overlap significantly. The localised corrosion susceptibility is affected by S and inhomogeneous 2nd phase particles. 相似文献
158.
A synthetic route for the preparation of 9-phenyl-1,2,4-triazolo[4,3-c]pteridines 8 is described. Their reactivities towards xanthine oxidase from Arthrobacter M-4 are determined and compared with the pteridine derivatives 6-phenylpteridin-4[3H]-thione 5, 6-phenyl-4-thiomethylpteridine 6, 4-hydrazino-6-phenylpteridine 7, 3-N-methyl-6-phenylpteridin-4[3H]-thione 19, 4-amino-6-phenylpteridine 22 and 1-N-methyl-6-phenylpteridin-4[1H]-one 24, in order to inspect a possible influence of pyrimidine ring substitution pattern on their interaction with the bacterial enzyme. It has been suggested that a planar structure of the pteridine moiety and the substituents could be an important factor that so far has been overlooked when considering the enzyme activity. Some literature data are also discussed in view of revision of structure assignment of the compounds 12, 14, and 17. This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
159.
Toon Verstraelen Bartłomiej M. Szyja David Lesthaeghe Reinout Declerck Veronique Van Speybroeck Michel Waroquier Antonius P. J. Jansen Alexander Aerts Lana R. A. Follens Johan A. Martens Christine E. A. Kirschhock Rutger A. van Santen 《Topics in Catalysis》2009,52(9):1261-1271
Zeolite synthesis is driven by structure-directing agents, such as tetrapropyl ammonium ions (TPA+) for Silicalite-1 and ZSM-5. However, the guiding role of these organic templates in the complex assembly to highly ordered
frameworks remains unclear, limiting the prospects for advanced material synthesis. In this work, both static ab initio and
dynamic classical modeling techniques are employed to provide insight into the interactions between TPA+ and Silicalite-1 precursors. We find that as soon as the typical straight 10-ring channel of Silicalite-1 or ZSM-5 is formed
from smaller oligomers, the TPA+ template is partially squeezed out of the resulting cavity. Partial retention of the template in the cavity is, however,
indispensable to prevent collapse of the channel and subsequent hydrolysis.
相似文献
Rutger A. van Santen (Corresponding author)Email: |
160.
Bogusława Wierzbowska Krzysztof Piotrowski Joanna Koralewska Nina Hutnik Andrzej Matynia 《Korean Journal of Chemical Engineering》2009,26(1):175-181
The experimental data concerning kinetics of a continuous mass crystallization in L-sorbose - water system are presented and
discussed. Influences of L-sorbose concentration in a feeding solution and mean residence time of suspension in a working
volume of laboratory DT MSMPR crystallizer on the resulting crystal size distributions, thus on the nucleation and growth
kinetics, were determined. The kinetic parameter values were evaluated on the basis of size-independent growth (SIG) kinetic
model (McCabe’s ΔL law). It was observed that within the investigated range of crystallizer productivity (220–2,200 kg of
L-sorbose crystals m−3 h−1), a crystal product of mean size Lm from 0.22 to 0.28 mm and CV from 68.8 to 44.0% was withdrawn. The values of linear growth rate show increasing trend (from
6.6·10−8 to 7.6·10−8 m s−1) with the productivity enlargement (assuming constant residence time τ=900 s). Occurrence of secondary nucleation phenomena
within the circulated suspension, resulting from the crystals attrition and breakage was observed. The parameter values in
a design equation, matching linear growth rate and suspension density with nucleation rate were determined. 相似文献