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Turbulent structures in an optimal Taylor–Couette flow between concentric counter-rotating cylinders
The turbulent structures formed in a Taylor–Couette (TC) flow established between two concentric counter-rotating cylinders were explored numerically. The shear Reynolds number was set to Reshear = 8000 and the radius ratio was set to ri/ro = 0.5. An optimal flow corresponding to the maximal angular velocity transport between the cylinders was selected for the TC flow. The mean velocity profile reached its steepest value near the cylinders in the optimal TC flow. The streamwise velocity correlations at the outer cylinder in the gap exceeded those at the inner cylinder. The large convective transport of angular velocity in the gap generated a maximal angular velocity flux to achieve the optimal flow. The angular velocity flux generated by the momentum source exceeded that generated by the momentum sink. The vorticity dispersion was larger near the inner cylinder than near the outer cylinder, but vorticity stretching near the outer cylinder exceeded than that near the inner cylinder. The skin friction coefficient budgets were plotted using the velocity–vorticity correlation. The vortex stretching contributions dominated the skin friction budgets. The area near the inner cylinder was populated by stronger vortices, but their population density was smaller than the population density of the vortices near the outer cylinder. The probability density functions of the wall-normal and streamwise velocity fluctuations delineated the presence of the large wall-normal velocity fluctuations near the outer cylinder. 相似文献
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Abdollahi A Hassani A Ghosta Y Bernousi I Meshkatalsadat MH Shabani R Ziaee SM 《Natural product research》2012,26(1):77-83
The effects of postharvest spraying of essential oils from sweet basil (Ocimum basilicum), fennel (Foeniculum vulgare), summer savory (Satureja hortensis) and thyme (Thymus vulgaris) on fungal decay and quality parameters of the 'Thompson seedless' table grape stored at 0?±?1°C for 60 days were evaluated. Results showed that the essential oils, especially of thyme and fennel, have a good inhibitory effect on the development of fungal decay in Thompson table grapes. In addition, essential oils reduced weight loss, berry and rachis browning and had no considerable adverse effect on the flavour of the fruits. GC-MS analysis showed that the main compounds identified in sweet basil, fennel, summer savory and thyme oils are linalool (65.25%), trans-anethole (64.72%), carvacrol (54.14%) and β-ocimene (12.62%), respectively. Therefore, these essential oils have good potential for use as an alternative to synthetic fungicides for the preservation and storage of table grapes. 相似文献
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Water-distilled essential oils from leaves of Hymenocrater yazdianus Rech.f., flowers of Stachys obtusicrena Boiss., and stems and flowers of Nepeta asterotricha Rech.f., which are endemic to Iran, were analyzed by GC and GC/MS. Fifty-five components of the leaf oil of H. yazdianus were characterized, representing 95.1% of the total components detected. The major constituents were identified as 1,8-cineole (17.6%), beta-caryophyllene (13.9%), alpha-pinene (10.6%) and caryophyllene oxide (10.4%). Germacrene-D (37.5%) and alpha-bisabolol (23.5%) were the main components among the twenty constituents characterized in the flower oil of S. obtusicrena, representing 90.8% of the total components detected. Thirty-five compounds representing 93.0% of the stem oil of N. asterotrica were identified among which terpinen-4-ol (22.8%) and gamma-terpinene (14.1%) were the major ones. The flower oil of the species was characterized by higher amounts of terpinen-4-ol (24.8%), 4a alpha, 7a beta-nepetalactone (18.2%) and 1,8-cineole (11.6%) among the thirty-three components comprising 98.5% of the total oil detected. The antibacterial activity of the stem, leaf and flower oils of Hymenocrater yazdianus, Stachys obtusicrena and Nepeta asterotricha against seven Gram-positive and Gram-negative bacteria were determined using the MIC method. The growth inhibitory zone (mm) was also measured. 相似文献
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Oladee Razieh Zareyee Daryoush Khalilzadeh Mohammad A. 《Monatshefte für Chemie / Chemical Monthly》2020,151(4):611-615
Monatshefte für Chemie - Chemical Monthly - Potassium fluoride impregnated on clinoptilolite nanoparticles (KF/CP NPs) have been explored to serve as an effective and inexpensive heterogeneous... 相似文献
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Razieh Nejat Mohammad Amin Mahjoub Zahra Hekmatian Mohammad Amin Javidi Sadegh Babashah 《Journal of the Iranian Chemical Society》2018,15(5):1133-1143
A series of pyrazolo[1,2-a][1,2,4]triazole-1,3-dione derivatives were synthesized under the catalytic effect of Natrolite zeolite, and their cytotoxic effects on three human breast cancer cell lines viz. breast cancer (BT-474), triple negative breast cancer (MDA-MB 231), and breast carcinoma (MCF-7) were explored using MTT assay. Apoptotic effects of the compounds were investigated by western blot analysis on the caspase-3 protein. Moreover, we examined the level of reactive oxygen species in all three cell lines. The most promising compound, 7-Amino-1,3-dioxo-5-(4-nitrophenyl)-2-phenyl-1,2,3-trihydropyrazolo[1,2-a][1,2,4]triazole-6-carbonitrile (4c), showed high levels of cytotoxicity against all cell lines with IC50 values of 2.3, 2.5 and 3 μg/ml, respectively. 相似文献
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Razieh FAZAELI Hamid ALIYAN Shahram TANGESTANINEJAD Esmaeel MOHAMMADI Maryam BORDBAR 《催化学报》2012,(2):237-246
The elimination of the silica matrix of composites by HF occurred by a two-step reaction deposition of a Cs2.5H0.5PW12O40(CsHPW) salt nanocrystal.We used 2D hexagonal SBA-15 silica as a template for the nanofabrication of CsHPW nanoparticles.Nanocast CsHPW materials are stable against leaching and colloidization in polar solvents.The catalytic performance of the nanocast CsHPW materi-als exceeded that of bulk Cs2.5H0.5PW12O40,which is the most active among the acidic HPW salts.A series of novel 1,3,5-triaryl-pyrazoline derivatives were synthesized by the reaction between chalcone and phenylhydrazine in high yield in the presence of CsHPW salt nanocrystals. 相似文献
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In crystal engineering and pharmaceutical chemistry, co-crystals have a wide range of applications. Ethenzamide (EA) is found to form co-crystal with 2-nitrobenzoic acid (NBA). Geometry properties like stability energy, charge distribution, bond length, electronic properties and thermodynamic characteristics have been analyzed. The C–H?O hydrogen bond involves C–H of EA and oxygen of NBA. Configuration with the angle, N3–C4–C5–C6 gives the lowest energy conformation. Partition coefficient value suggests that EA-NBA has pharmaceutics behavior. RMSD values show the simulation's relative stability and the complexes, remained stable throughout. 相似文献