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41.
42.
Mekala BikshapathiAshish Sharma Ashutosh Sharma Nishith Verma 《Chemical Engineering Research and Design》2011,89(9):1737-1746
In this study, a hierarchal web of carbon micro and nanofibers was used as a precursor for the synthesis of a carbon molecular sieve (CMS). CMSs were prepared by thermal treatment of carbon fibers using a microwave heating device. The heating power and treatment time were optimized for the maximum performance of the prepared CMS for the separation of CO2 at low concentrations from the gaseous mixture of CO2 and air under dynamic (flow) conditions. Based on the experimental data, microwave power input of 240 W and treatment time of 15 min were found to be suitable for the maximum uptake of CO2 by CMS. Adsorption breakthrough curves were obtained at different gas flow rates and CO2 concentrations. CMSs prepared from the hierarchal web of carbon micro and nanofibers were found to be superior to those prepared from ACF. The CO2 uptake was determined to be approximately 0.88 mg/g and 10 mg/g at concentrations of 500 ppm and 5000 ppm, respectively, in air. 相似文献
43.
The physicochemical and interfacial properties of the monomeric surfactants cetyltrimethyl ammonium bromide (CTAB), cetyltriphenyl
phosphonium bromide (CTPB), tetradecyl triphenyl phosphonium bromide (TTPB), cetyldiethylethanol ammonium bromide (CDEEAB),
cetyltrimethyl ammonium chloride (CTACl), tetradecyltrimethyl ammonium bromide (TTAB), and a gemini surfactant (C16-3-C16, 2Br−) at different pH (3.1, 7.0, and 7.75) have been investigated by conductivity and surface tension measurements at 300 K. The
critical micellar concentration (CMC), degree of micellar ionization (α), surface excess concentration (Гmax), minimum surface area per molecule of surfactant (A
min), Gibbs free energy of micellization (∆G
m0), surface pressure at the CMC (π
CMC), and the Gibbs energy of adsorption (∆G
ads0) of the monomeric surfactants have also been determined. The CMC, α and Гmax, increase with increasing pH whereas A
min decreases. 相似文献
44.
Deepak Kumar Shefali Verma Kartikey Verma Sudipta Som Vijay Kumar Hendrik C. Swart 《Ceramics International》2018,44(12):13649-13653
Herein, nanocrystals of Er3+ and Er3+, Yb3+ co-doped NaYF4 upconversion (UC) phosphor were prepared via the reverse-microemulsion method. The impact of different concentrations of Er3+ ions on the UC emission intensity after 980?nm diode laser excitation is discussed. The structure, morphology and composition of the nanophosphors were confirmed by X-ray diffraction, transmission electron microscopy, scanning electron microscopy and the results showed the presence of NaYF4 nanocrystals with hexagonal phases of NaYF4. The UC spectra revealed two emission bands including a green and a red emission band and the CIE coordinate for the samples were estimated. The present research revealed that the reverse-microemulsion approach will be suitable for the synthesis of efficient upconversion nanophosphors. 相似文献
45.
Rajesh B. Gujar Parveen K. Verma Bholanath Mahanty Seraj A. Ansari Dibakar Goswami 《分离科学与技术》2020,55(14):2560-2569
ABSTRACT Solvent extraction studies were performed to understand the extraction behavior of Np4+ and NpO2 2+ from acidic feeds with CMPO (octyl (phenyl)-N,N-diisobutyl carbamoyl methyl phosphine oxide) dissolved in 1-butyl-3-methylimidazolium bis(trifluoromethane sulfonyl)imide, a water immiscible ionic liquid. Slope analyses on the distribution data revealed the extraction of ML2 type species, where M = Np4+ or NpO2 2+, and L = CMPO. Studies were also carried out with Pu4+ and UO2 2+ under identical conditions. The nature of the extracted species was found to vary with the nature of the ionic species. 相似文献
46.
Shalu Kataria Yogendra L. Verma Himani Gupta Shishir K. Singh Nitin Srivastava Ravindra Dhar 《Polymer-Plastics Technology and Engineering》2020,59(9):952-958
ABSTRACTNano-composite polymer gel electrolytes (NPGEs) based on polymer poly(vinylidene fluoride-co-hexafluoropropylene) PVdF-HFP, ionic liquid, 1-butyl-3- methylimidazolium bis(trifluoromethanesulfonyl)imide BMIMTFSI, Li-salt along with the addition of SiO2 nanoparticles have been synthesized and characterized by various techniques. Prepared NPGEs show high room temperature ionic conductivity (~10?3 S/cm) and have a wide electrochemical window (ECW) (~3.3–3.5 V). The galvanostatic charge/discharge profile was studied by sandwiching best performing NPGEs between a LiFePO4 cathode and lithium metal anode. The specific discharge capacity of the cell (Li/NPGE/LiFePO4) room temperature at 0.1C rate is found to be 138 mAh/g. 相似文献
47.
Taur Prakash Pandurang Bintu Kumar Narshimha Verma Debabrata Ghosh Dastidar Risa Yamada Tatsuya Nishihara Prof. Kazuhito Tanabe Prof. Dalip Kumar 《ChemMedChem》2023,18(1):e202200405
Six methyl pheophorbide-a derivatives were prepared by linking a tryptamine side chain at the C-13 1 , C-15 2 and C-17 3 positions of pheophorbide-a. P repared conjugates were characterized and evaluated for their photocytotoxicity against A549 cells. The conjugate 6 a with strong absorption at 413 nm (Soret band), 663–671 nm (Q bands) and comparable fluorescence quantum yield (0.26) was found to exhibit significant cytotoxicity (659 nM). Molecular integration of pheophorbide-a and tryptamines showed synergistic effects as the most potent conjugate 6 a was identified with enhanced photocytotoxicity when compared to methyl pheophorbide-a. T he conjugate 6 a was smoothly taken up by A549 cells and exhibited intracellular localization predominantly to lysosome in the cytoplasm. Upon photoirradiation 6 a generated singlet oxygen to show potent cytotoxicity toward A549 cells. 相似文献
48.
Arun K. Verma V. Rajkumar Ravindra Kumar K. Gururaj Tarun Pal Singh Manoj K. Singh 《European Journal of Lipid Science and Technology》2023,125(10):2300143
This study investigated the effect of supplementing omega fatty acids-rich oil blend, composed of sunflower oil (1.5% and 3.0%), linseed oil (1.5% and 3.0%), and FineXNV1810 (20 g) on the carcass, meat quality, fatty acid profile, and genes (peroxisome proliferator-activated receptor-α, stearoyl-CoA desaturase, acetyl-CoA carboxylase, hydroxy-3-methylglutaryl coenzyme A, and leptin) of Barbari goats. The goat kids (n = 18) were divided into three groups, namely, group A: basal diet; group B: basal diet + oil blend level 1; and group C: basal diet + oil blend level 2, and subjected to the feeding trial for 120 days followed by slaughter and meat quality studies. No treatment effect was recorded in carcass characteristics, pH, water holding capacity, and proximate composition of meat. However, a significant (p < 0.05) treatment effect was observed in cooking loss, lightness, yellowness, and shear force values of meat. There were significant differences (p < 0.05) in linoleic acid, α-linolenic acids, conjugated linoleic acid (CLA), polyunsaturated fatty acids (PUFA), n − 3 and n − 6 PUFA, PUFA/saturated fatty acids and n − 6/n − 3 ratios, and thrombogenic index among groups. An upregulation of the studied genes in the supplemented groups was observed. There were upregulations in the studied genes in the supplemented groups. Practical applications: Goat meat is in great demand the world over, especially in tropical countries, including India, and does not carry any social or religious prohibition. Although goat meat has relatively less fat, consumers express their concern over the presence of undesirable fatty acids. The present study shows that the fatty acid configuration of goat meat can be improved by a dietary supplementation of an oil blend rich in omega fatty acids. The amount of n − 3 PUFA, n − 6 PUFA, and CLA in goat meat was significantly increased due to the dietary oil blend making it healthy for the consumers. Moreover, the dietary oil blend at the studied levels did not significantly affect the growth and meat quality parameters of the goats. Thus, the studied approach can be successfully followed to produce healthier goat meat. 相似文献
49.
In the present work, a numerical study has been carried out to predict transient gas flow and pressure behaviour in a gas manifold system. The start‐up and shutdown of the system, varying demands at the consumer ends, malfunctioning of compressors and valves are a few examples of common causes of transience in a gas delivery system. In particular, the sensitivity of oscillations in pressure and mass flux to variation in pipe dimensions, supply pressure and gas flow rate are ascertained under the aforementioned conditions of transience. The present results show that large pipe dimensions, high gas flow rate and high upstream pressure in the branch in which the disturbance is introduced, all cause greater amplitude in mass flux and pressure oscillations in the neighboring branches. The duration of oscillations is also found to be longer. The present study has practical importance in designing as well as in operating, a gas delivery system. 相似文献
50.
The textural and electrooptical behavior of a nematic liquid crystal (LC) dispersed in a flexible and rigid polyester was studied. The dispersion of LC in the polymer matrix and light transmission through the polymer‐dispersed liquid crystal (PDLC) is governed by the nature of the polymer, its molecular weight, and the applied voltage. It was observed that the transmission of light and the dispersion of LC maximizes their respective values at the minimum molecular weight irrespective of the nature of the polymer and at the maximum voltage. The reason is the predominance of chain alignment over entanglement at the minimum molecular weight. As molecular weight increases, the transmission of light as well as the dispersion of LC in the polymer may increase or decrease depending on the predominance of chain entanglement or chain alignment. The alignment of LC droplets in the direction of the applied voltage is increased by an increase in the applied voltage, causing enhancement of the light transmission. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 284–289, 2003 相似文献