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Muhammad A. Khosa Syed Sakhawaat Shah 《Journal of Dispersion Science and Technology》2013,34(7):1002-1007
Reactive black 5 (RB-5) dye was removed from a water stream using two cationic surfactants, cetyltrimethylammonium bromide (CTAB) and cetylpyridinium chloride (CPC), via micellar enhanced ultrafiltration. Three membranes with different pore size were used for the determination of rejection coefficient and permeate flux of the solution at 1.5 bar trans-membrane pressure (TMP). The two surfactants (CPC and CTAB) played an almost negligible role in rejection efficiency with 5000 and 10,000 molecular weight cut-off membrane (MWCO), respectively. In this case, high rejection and low permeate flux was the result of a larger molecular size of RB-5 DYE being retained by comparatively smaller sized pores of membrane via ultrafiltration. However, CPC and CTAB surfactants showed 83% and 98% rejection coefficient, respectively, at a concentration greater than their CMC values against 30,000 MWCO. Permeate flux remained low and constant in presence of 5000 and 10,000 MWCO with a small variation against 30,000 MWCO for the two surfactants, thereby no appreciable effect on both surfactant concentrations on concentration polarization was estimated. Thus, RB-5 dye alone was determined to be responsible for membrane plugging or concentration polarization and ultimately for low permeate flux. The effect of trans-membrane pressure was also investigated during this study. 相似文献
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Dielectric characteristics of neodymium heptamolybdate crystals grown by gel encapsulation technique
Sushma Bhat S. K. Khosa Dr. P. N. Kotru R. P. Tandon 《Crystal Research and Technology》1995,30(2):267-273
Results obtained from the dielectric studies of neodymium heptamolybdate crystals grown in the system Nd(NO3)3 –MoO3 –NH4OH– HNO3 —Na2SiO3 by gel encapsulation technique are presented. The variation of dielectric constant (ε′), dielectric loss (tanδ) and conductivity (σ) with frequency at different temperatures is studied. The dielectric constant of the material increases sharply, attains a peak value and then decreases rapidly, as material's temperature rises from room temperature to higher degrees. The temperature at which the peak value is attained is the transition temperature of the material. Dielectric loss (tan δ) follows almost a similar behaviour. The conductivity (σ) is also found to be temperature-and frequency-dependent. This sharp rise in ε′ is attributed to the contribution from space charge polarization. Theoretically obtained data using the expression ε′ = a0 + a1 T2 and —In σ = a + b(T — T0)2 for T < T0) fits very well with the experimentally obtained data indicating that space charge polarization increases as some power of temperature larger than one. 相似文献
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M. K. Khosa P. T. Wood S. M. Humphrey W. T. A. Harrison 《Journal of Structural Chemistry》2015,56(6):1130-1135
The syntheses and crystal structures of the layered coordination polymers M(C8H8NO2)2 [M = Mn (1), Co (2), Ni (3) and Zn (4)] are described. These isostructural compounds contain centrosymmetric trans-MN2O4 octahedra as parts of infinite sheets; the ligand bonds to three adjacent metal ions in μ3-N,O,O′ mode from both its carboxylate O atoms and its amine N atom. In each case, weak intra-sheet N–H?O and C–H?O hydrogen bonds may help to consolidate the structure. Crystal data: 1, C16H16MnN2O4, M r = 355.25, monoclinic, P21/c (No. 14), a = 10.6534(2) Å, b = 4.3990(1) Å, c = 15.5733(5) Å, β = 95.1827(10)°, V = 726.85(3) Å3, Z = 2, R(F) = 0.026, wR(F 2) = 0.067. 2, C16H16CoN2O4, M r = 359.24, monoclinic, P21/c (No. 14), a = 10.6131(10) Å, b = 4.3374(4) Å, c = 15.3556(17) Å, β = 95.473(4)°, V = 703.65(12) Å3, Z = 2, R(F) = 0.041, wR(F 2) = 0.091. 3, C16H16N2NiO4, M r = 359.02, monoclinic, P21/c (No. 14), a = 10.6374(4) Å, b = 4.2964(2) Å, c = 15.2827(8) Å, β = 95.9744(14)°, V = 694.66(6) Å3, Z = 2, R(F) = 0.028, wR(F 2) = 0.070. 4, C16H16N2O4Zn, M r = 365.68, monoclinic, P21/c (No. 14), a = 10.6385(5) Å, b = 4.2967(3) Å, c = 15.2844(8) Å, β = 95.941(3)°, V = 694.89(7) Å3, Z = 2, R(F) = 0.038, wR(F 2) = 0.107. 相似文献
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Alharbi F. F. Aman Salma Ahmad Naseeb Ejaz Syeda Rabia Khosa Rabia Yasmin Abid Abdul Ghafoor Manzoor Sumaira Al-Buriahi M. S. Alrowaili Z. A. Farid Hafiz Muhammad Tahir 《Journal of Solid State Electrochemistry》2022,26(5):1251-1258
Journal of Solid State Electrochemistry - Scientists are increasingly interested in improving electroactive technologies for supercapacitor applications, since energy storage devices have improved... 相似文献
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The functional Ito formula, in the form df() = f( + d ) f(),is formulated and proved in the context of a Lie algebra L associatedwith a quantum (non-commutative) stochastic calculus. Here fis an element of the universal enveloping algebra U of L, andf() + d() f() is given a meaning using the coproductstructure of U even though the individual terms of this expressionhave no meaning. The Ito formula is equivalent to a chaoticexpansion formula for f() which is found explicitly. 1991 MathematicsSubject Classification: primary 81S25; secondary 60H05; tertiary18B25. 相似文献
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S. Verma R. Devi S. K. Khosa 《The European Physical Journal A - Hadrons and Nuclei》2006,30(3):531-539
The yrast spectra of 78-82Kr are studied by using the projected shell model (PSM) approach. The energy states are obtained by taking oblate as well
as prolate quadrupole deformations for 78-82Kr. The structure of yrast states and backbending phenomena are investigated. The theoretical results predict low-lying states
in 78, 82Kr to be oblate and coexistence of oblate-prolate shapes for 80Kr. The B(E2) transition probabilities and g-factors are obtained and compared with the available experimental data. 相似文献
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Muhammad Arshad Khosa S. Sakhawat Shah Muhammad Faizan Nazar 《Journal of Dispersion Science and Technology》2013,34(11):1634-1640
Ultraviolet spectrometric study of alizarin red S (ARS) showed the substantial change in dye spectra by cationic CTAB as compared to anionic SDS and nonionic TX-100 surfactant. High spectral change by CTAB confirms the anionic nature of ARS dye and thus ARS-CTAB complex formation takes place due to electrostatic force of attraction. A little spectral change by SDS is the result of similarly charged repulsive forces that overcome weak hydrophobic-hydrophobic interaction between dye and surfactant micelles. TX-100 exhibited moderate spectral effect responsive to weak hydrophobic-hydrophobic interaction alone. MEUF study of ARS dye justified the spectral changes and dye rejection percentage (R) decreases in the following order: cationic > nonionic > anionic surfactant. Permeate flux (J) slightly decreases in presence of CTAB and it remains virtually constant for both SDS and TX-100. Addition of copper salt (i.e., CuCl2) in dye-CTAB complex solution, favors rejection (%) removing dye and copper simultaneously via micellar enhanced ultrafiltration. 相似文献