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101.
Adsorption of hexavalent chromium on manganese nodule leached residue obtained from NH3-SO2 leaching
Adsorption of hexavalent chromium onto manganese nodule leached residues was investigated as a possible alternative to the conventional methods of its removal from aqueous synthetic solutions. Adsorption behavior was studied as a function of time, pH, temperature, and concentration of adsorbate and adsorbent in acetic acid-sodium acetate buffer medium. Cr (VI) removal was pH dependent and was found to be of a maximum at pH 3. The applicability of the Langmuir isotherm to the present system was tested. Increased adsorption capacity with increased temperature indicates that the adsorption reaction was endothermic in nature. Based on these studies, thermodynamic parameters such as Gibbs free energy change (DeltaG0), standard enthalpy change (DeltaH0), and standard entropy change (DeltaS0) were calculated. 相似文献
102.
试射法在求解二阶线性微分方程边值问题中的应用 总被引:1,自引:0,他引:1
对二阶线性微分方程的边值问题(第一类、第二类及第三类边值条件),通常可利用古典的差分方法进行求解,即通过对微分方程离散化而求解线性方程组得到原微分方程的解.通过数值实验说明试射法也可作为求解二阶线性微分方程的一种有效算法且能保证具有较高的精度. 相似文献
103.
Parthasarathi Bera H. Seenivasan K. S. Rajam C. Shivakumara Sanjit Kumar Parida 《Surface and interface analysis : SIA》2013,45(6):1026-1036
Electrodeposition of Co–W alloy coatings has been carried out with DC and PC using gluconate bath at different pH. These coatings are characterized for their structure, morphology and chemical composition by X‐ray diffraction, field emission scanning electron microscopy, differential scanning calorimetry and X‐ray photoelectron spectroscopy (XPS). Alloy coatings plated at pH8 are crystalline, whereas coatings electrodeposited at pH5 are nanocrystalline in nature. XPS studies have demonstrated that as‐deposited alloy plated at pH8 with DC contain only Co2+ and W6+ species, whereas that alloy plated at pH5 has significant amount of Co0 and W0 along with Co2+ and W6+ species. Again, Co2+ and W6+ are main species in all as‐deposited PC plated alloys in both pH. Co0 concentration increases upon successive sputtering of all alloy coatings. In contrast, mainly W6+ species is detected in the following layers of all alloys plated with PC. Alloys plated at pH5 show higher microhardness compared to their pH8 counterparts. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
104.
Ram Avtar Jat S. C. Parida J. Nuwad Renu Agarwal S. G. Kulkarni 《Journal of Thermal Analysis and Calorimetry》2013,112(1):37-43
The ZrCo–H2 system was investigated in this study owing to its importance as a suitable candidate material for storage, supply, and recovery of hydrogen isotopes. Desorption hydrogen pressure-composition isotherms were generated at six different temperatures in the range of 524–624 K. A van’t Hoff plot was constructed using the plateau pressure data of each pressure-composition isotherms and the thermodynamic parameters were calculated for the hydrogen desorption reaction of ZrCo hydride. The enthalpy and entropy change for the desorption of hydrogen were found to be 83.7 ± 3.9 kJ mol?1 H2 and 122 ± 4 J mol?1 H2 K?1, respectively. Hydrogen absorption kinetics of ZrCo–H2 system was studied at four different temperatures in the range of 544–603 K and the activation energy for the absorption of hydrogen by ZrCo was found to be 120 ± 5 kJ mol?1 H2 by fitting kinetic data into suitable kinetic model equation. 相似文献
105.
S. C. Parida N. S. Anand Ram Avtar Jat S. G. Kulkarni 《Journal of Thermal Analysis and Calorimetry》2013,112(1):173-177
Order–disorder phase transitions in Cu0.6Pd0.4 and Cu0.85Pd0.15 alloys have been investigated using differential scanning calorimetry and drop calorimetry. The differential scanning calorimetry measurements show that the transition in both these alloys are reversible in nature and the enthalpy increment measurements reveal that these transitions are first order in nature. The transition temperature of first-order phase transition in Cu0.6Pd0.4 and Cu0.85Pd0.15 alloys have been evaluated to be 884(±2) and 799(±2) K, respectively, from drop calorimetric measurements. The latent heat of first-order phase transition in Cu0.6Pd0.4 alloy were evaluated to be 31.2(±0.6) and 28.9(±0.5) J g?1, by enthalpy increment and differential scanning calorimetry measurements, respectively. Similarly, the latent heat of first-order phase transition in Cu0.85Pd0.15 alloy were evaluated to be 23.1(±0.6) and 21.3(±0.5) J g?1, by enthalpy increment and differential scanning calorimetry measurements, respectively. The solidus temperatures of Cu0.6Pd0.4 and Cu0.85Pd0.15 alloys were found to be 1,457(±2) and 1,360 K, respectively. 相似文献
106.
Sanju Das Sushanta Kumar Parida Tanumoy Mandal Laxmikanta Sing Suman De Sarkar Sandip Murarka 《化学:亚洲杂志》2020,15(5):568-572
An organophotoredox catalyzed efficient and robust approach for the synthesis of highly important 3‐alkyl substituted chroman‐4‐one scaffold is developed using visible light induced radical cascade cyclization strategy. The reaction is initiated through the generation of alkyl radicals from N‐(acyloxy)phthalimides under photoredox conditions, which subsequently undergo intermolecular cascade radical cyclization on 2‐(allyloxy)arylaldehydes to afford chroman‐4‐one scaffolds. The presented strategy is attractive with regard to mild reaction conditions, operational simplicity, high functional group tolerance and broad substrate scope. 相似文献
107.
The Aurivillius phase-based composition bearing chemical formula Bi4Pb2Zr2TiFeNbO18 (termed as BPZTFNO) was synthesized by a solid-state method. The structural analysis as obtained from the X-ray pattern has depicted an orthorhombic phase. The various size and morphology of grains are distributed throughout the natural surface as revealed from microstructure analysis. The dielectric and electrical study of the BPZTFNO is taken at a various sweep of frequency (1 kHz–1 MHz) and temperatures (25–400 °C). The ferroelectric-paraelectric phase transition is well illustrated from the temperature-dependent dielectric constant. The complex impedance analysis suggests the association of grain effect. The relaxation of non-Debye nature is shown in the impedance study. The formed sample is subjected to an electric field and further its excitation performance is examined suggesting its possible usage in devices. 相似文献
108.
M. K. Parida 《Pramana》1995,45(Z1):209-228
We discuss recent contributions on threshold effects in grand unfiied theories including minimal SUSY SU (5), non-SUSY modifications
of the grand desert in SU(5) and SO(10), and SO(10) with single intermediate symmetires. Consequences of theorems on vanishing
GUT-scale corrections to sin2 θw in SO(10) with SU(2)
L
XSU(2)
R
XSU(4)
c
(g2l
=g2R
) intermediate symmetry are discussed and vanishing corrections on the inter-mediate scale are explicitly demonstrated where
predictions are more precise. Threshold and higher dimensional operator effects in SUSY SU(5) recently derived by a number
of authors are presented. 相似文献
109.
An analysis has been carried out to study the effect of magnetic field on an electrically conducting fluid of second grade
in a parallel channel. The coolant fluid is injected into the porous channel through one side of the channel wall into the
other heated impermeable wall. The combined effect of inertia, viscous, viscoelastic and magnetic forces are studied. The
basic equations governing the flow and heat transfer are reduced to a set of ordinary differential equations by using appropriate
transformations for velocity and temperature. Numerical solutions of these equations are obtained with the help of Runge-Kutta
fourth order method in association with quasi-linear shooting technique. Numerical results for velocity field, temperature
field, skin friction and Nusselt number are presented in terms of elastic parameter, Hartmann number, Prandtl number and Reynolds
number. Special case of our results is in good agreement with earlier published work. 相似文献
110.
Moorthy JN Senapati K Parida KN Jhulki S Sooraj K Nair NN 《The Journal of organic chemistry》2011,76(23):9593-9601
The methyl groups in TetMe-IBX lower the activation energy corresponding to the rate-determining hypervalent twisting (theoretical calculations), and the steric relay between successive methyl groups twists the structure, which manifests in significant solubility in common organic solvents. Consequently, oxidations of alcohols and sulfides occur at room temperature in common organic solvents. In situ generation of the reactive TetMe-IBX from its precursor iodo-acid, i.e., 3,4,5,6-tetramethyl-2-iodobenzoic acid, in the presence of oxone as a co-oxidant facilitates the oxidation of diverse alcohols at room temperature. 相似文献