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51.
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
52.
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
53.
Jayaprakash Behera Swapnita Patra Shaikh Nazrul Satendra Kumar Sharma Deepak Kumar Mahendra Kumar Verma Anil Kumar Katare Sarat K. Swain 《应用聚合物科学杂志》2024,141(16):e55246
Herein, nano boron nitride (BN) laminated poly(ethyl methacrylate) (PEMA)/poly(vinyl alcohol) (PVA) nanocomposite films are fabricated by using a simple in situ polymerization technique with incorporation of silver nanoparticles (Ag NPs). Structural investigations of PEMA/PVA/Ag@BN nanocomposite thin films are carried out by Fourier-transform infrared spectroscopy, dynamic light scattering, X-ray diffraction analysis, 1H nuclear magnetic resonance, 13C nuclear magnetic resonance, and mass spectrometry. The change in morphology of PEMA/PVA matrix due to the reinforcement of BN platelets are identified by electron microscopic studies. The unique tortuous paths are achieved by the dispersion of BN platelets by which gas penetration is restricted with enhancing the barrier properties of the material by 6.5 folds at 5 wt% BN content as compared with neat PEMA/PVA. Acid and alkali resistant along with biodegradability behavior of as-synthesized nanocomposites are studied. From limiting oxygen index (LOI) results, it is found that the prepared materials are fire retardant in nature owing to effective reinforcement of BN layers. Antibacterial activities of PEMA/PVA/Ag@BN nanocomposite are studied by Xanthomonas citri or axonopodis pv. Citri, Escherichia coli, and Xanthomonas oryzae pv. Oryzae because of Ag NPs reinforcement. The substantial improvements in gas barrier, fire retardant, and antibacterial properties enable the materials for packaging application. 相似文献
54.
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
55.
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
56.
Polypropylene random copolymer/MWCNT nanocomposites: Isothermal crystallization kinetics,structural, and morphological interpretations 下载免费PDF全文
This article describes the crystallization process of polypropylene random copolymer (PPCP) under isothermal conditions in presence of varying amounts of multiwalled carbon nanotubes (MWCNT) ranging from 0.5 to 4.0% w/w. Increase in the crystallization temperature under dynamic conditions confirmed the nucleating behavior of MWCNTs, which was also corroborated by crystallization studies under isothermal conditions. The crystallization kinetics was analyzed using Avrami equation and the parameters such as Avrami exponent, the equilibrium melting temperature and fold surface energy for the crystallization of PPCP chains in nanocomposites were obtained from the calorimetric data in order to determine the effect of MWCNTs on these parameters. Spherulitic growth of PPCP crystals was also investigated as a function of time and MWCNT content using hot stage polarizing microscope. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41734. 相似文献
57.
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
58.
Chethana Rao Syamantak Khan Navneet C. Verma Dr. Chayan Kanti Nandi 《Chembiochem : a European journal of chemical biology》2017,18(24):2385-2389
We present efficient labelling of several proteins with orange‐emissive carbon dots. N‐Hydroxysuccinimide was used to activate the carboxyl groups of carbon dots, which subsequently reacted with the lysine groups present on the protein. Labelling was confirmed by UV absorption spectroscopy, PAGE and fluorescence correlation spectroscopy. Protein‐conjugated carbon dots showed an enhancement in fluorescence lifetime and intensity owing to reduced intramolecular dynamic fluctuations. Single‐molecule fluorescence measurements showed reduced fluorescence fluctuations and higher photon budget after protein tagging. Our study opens up opportunities to use carbon dots as highly precise biolabelling probes. 相似文献
59.
Biodegradable counterparts of petro plastics for packaging applications are highly desired due to environmental considerations. Agar can be a potential material due to its availability and biodegradability. However, moderate mechanical strength and thermal stability, in addition to poor resistance against water, needs to be addressed before agar can be commercially implemented as packaging material. As a step toward this objective, graphene oxide (GO) and reduced GO (RGO) were incorporated in agar and were solution casted in the form of films. The tensile strength was increased by 118.4% and 69.4% at 2% GO and 2% RGO loading, respectively. Higher interfacial bonding between GO and agar compared to that of RGO and agar was attributed for the observed mechanical properties. Resistance to swelling and hydrophobicity (contact angle) of the composite were improved as well when compared to pure agar. The tensile strength and the contact angle values were however, decreased after the addition of 2% GO and 2% RGO. The morphological investigation showed that the formation of pores at higher concentration of reinforcement was the contributing factor for the decrease in tensile strength. No significant change in thermal properties was observed. The transmittance value was reduced to 0% after the incorporation of GO and RGO. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45085. 相似文献
60.