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41.
Xiaohang Zhang Christopher A. Paddon Yohan Chan Philip C. Bulman‐Page Paul S. Fordred Steven D. Bull Ho‐Chol Chang Nadeem Rizvi Frank Marken 《Electroanalysis》2009,21(12):1341-1347
Mineral oil microdroplets containing the model antioxidant N,N‐didodecyl‐N′,N′‐diethyl‐phenylene‐diamine (DDPD) are immobilized into a 100×100 pore‐array (ca. 10 μm individual pore diameter, 100 μm pitch) in a boron‐doped diamond electrode surface. The robust diamond surface allows pore filling, cleaning, and reuse without damage to the electrode surface. The electrode is immersed into aqueous electrolyte media, and voltammetric responses for the oxidation of DDPD are obtained. In order to further improve the current responses, 20 wt% of carbon nanofibers are co‐deposited with the oil into the pore array. Voltammetric signals are consistent with the oxidation of DDPD and the associated transfer of perchlorate anions (in aqueous 0.1 M NaClO4) or the transfer of protons (in aqueous 0.1 M HClO4). From the magnitude of the current response, the DDPD content in the mineral oil can be determined down to less than 1 wt% levels. Perhaps surprisingly, the reversible (or midpoint) potential for the DDPD oxidation in mineral oil (when immersed in 0.1 NaClO4) is shown to be concentration‐dependent and to shift to more positive potential values for more dilute DDPD in mineral oil solutions. An extraction mechanism and the formation of a separate organic product phase are proposed to explain this behavior. 相似文献
42.
S. Nadeem Noreen Sher Akbar 《Communications in Nonlinear Science & Numerical Simulation》2009,14(12):4100-4113
Peristaltic transport in a two-dimensional non-uniform tube filled with Herschel–Bulkley fluid is studied under the assumptions of long wavelength and low Reynold number. The fluid flow is investigated in the wave frame of reference moving with the velocity of the peristaltic wave. Exact solution for the velocity field, the temperature profile, the stream functions and the pressure gradient are obtained. The physical behavior of τ, n, α and on the pressure rise versus flow rate are discussed through graphs. At the end of the article trapping phenomena for Herschel–Bulkley and also for Newtonian, Bingham and power law (which are the special cases of Herschel–Bulkley fluid) fluid are discussed. 相似文献
43.
The present article investigates the dual nature of the solution of the magneto- hydrodynamic (MHD) stagnation-point flow of a Prandtl fluid model towards a shrinking surface. The self-similar nonlinear ordinary differential equations are solved numerically by the shooting: method. It is found that the dual solutions of the flow exist for cer- tain values of tile velocity ratio parameter. The special case of the first branch solutions (the classical Newtonian fluid model) is compared with the present numerical results of stretching flow. The results are found to be in good agreement. It is also shown that the boundary layer thickness for the second solution is thicker than that for the first solution. 相似文献
44.
An alytical and numerical study of peristaltic transport of a Johnson-Segalman fluid in an endoscope
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In the present study, we discuss the peristaltic flow of a Johnson-Segalman fluid in an endoscope. Perturbation, homotopy, and numerical solutions are found for the non-linear differential equation. The comparative study is also made to check the validity of the solutions. The expressions for pressure rise frictional forces, pressure gradient, and stream lines are presented to interpret the behavior of various physical quantities of the Johnson-Segalman fluid. 相似文献
45.
The present paper addresses the megnetohydrodynamic Jeffrey fluid flow with heat and mass transfer on an infinitely rotating upright cone. Inquiry is carried out with heat source/sink and chemical reaction effects. Further, constant thermal and concentration flux situations are imposed. Optimal homotopy analysis method (OHAM) is employed to achieve series solutions of the concerned differential equations. Important results of the flow phenomena are explored and deliberated by means of graphs and numerical tables. It is perceived that thermal boundary layer thickness possess contrast variations for the heat source and heat sink, respectively. The chemical reaction enhances the heat transfer rate but decline the mass transfer rate. Moreover, the precision of the existing findings is verified by associating them with the previously available work. 相似文献
46.
The main purpose of this article is to present a mathematical model of ciliary motion in an annulus. In this analysis, the peristaltic motion of non-Newtonian Jeffrey six constant fluid is observed in an annulus with ciliated tips in the presence of heat and mass transfer. The effects of viscous dissipation are also considered. The flow equations of non-Newtonian fluid for the two-dimensional tube in cylindrical coordinates are simplified using the low Reynolds number and long wave-length approximations. The main equations for Jeffrey six constant fluid are considered in cylindrical coordinates system. The resulting nonlinear problem is solved using the regular perturbation technique in terms of a variant of small dimensionless parameter α. The results of the solutions for velocity, temperature and concentration field are presented graphically. Bk is Brinkman number, ST is soret number, and SH is the Schmidth number. Outcome for the longitudinal velocity, pressure rise, pressure gradient and stream lines are represented through graphs. In the history, the viscous-dissipation effect is usually represented by the Brinkman number. 相似文献
47.
Impact of Linear Operator on the Convergence of HAM Solution: A Modified Operator Approach
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S. T. Hussain S. Nadeem & M. Qasim 《advances in applied mathematics and mechanics.》2016,8(3):499-516
The linear operator plays an important role in the computational process of
Homotopy Analysis Method (HAM). In HAM frame any kind of linear operator can
be chosen to develop a solution. Hence, it is easy to introduce the modified/physical
parameter dependent linear operators. The effective use of these operators has been
judged through solving fluid flow problems. Modification in linear operators affects
the solution and improves the computational efficiency of HAM for larger values of
parameters. The convergence rate of the solution is rapid and several times higher
resulting in less computational time. 相似文献
48.
Imran Ali Mohd Suhail Mohammad Nadeem Lone Zeid A. Alothman Abdulrahman Alwarthan 《液相色谱法及相关技术杂志》2016,39(9):435-444
It is a continuous chase of researchers to separate chiral racemates due to their dominance in the pharmaceutical industry, agrochemicals, and food additives. There are many analytical techniques which have been used to resolve one chiral center racemates, but, little the literature report is scanty for the resolution of multiple stereogenic center racemates. Therefore, in this article the efforts were made to describe the enantiomeric resolution of multiple stereogenic center racemates by different modalities of chromatography. The various modalities discussed are high-performance liquid chromatography, capillary electrophoretic chromatography, miceller electrokinetic chromatography, supercritical fluid chromatography, nanoliquid chromatography, and gas chromatography. Besides, the attempts have also been made to discuss the future challenges and prospectives of the enantiomeric resolution of multichiral racemates. 相似文献
49.
Purpose
Electron paramagnetic resonance (EPR) oximetry using variable length multi-probe implantable resonator (IR), was used to investigate the temporal changes in the ischemic and contralateral brain pO2 during stroke in rats.Material and methods
The EPR signal to noise ratio (S/N) of the IR with four sensor loops at a depth of up to 11 mm were compared with direct implantation of lithium phthalocyanine (LiPc, oximetry probe) deposits in vitro. These IRs were used to follow the temporal changes in pO2 at two sites in each hemisphere during ischemia induced by left middle cerebral artery occlusion (MCAO) in rats breathing 30% O2 or 100% O2.Results
The S/N ratios of the IRs were significantly greater than the LiPc deposits. A similar pO2 at two sites in each hemisphere prior to the onset of ischemia was observed in rats breathing 30% O2. However, a significant decline in the pO2 of the left cortex and striatum occurred during ischemia, but no change in the pO2 of the contralateral brain was observed. A significant increase in the pO2 of only the contralateral non-ischemic brain was observed in the rats breathing 100% O2. No significant difference in the infarct volume was evident between the animals breathing 30% O2 or 100% O2 during ischemia.Conclusions
EPR oximetry with IRs can repeatedly assess temporal changes in the brain pO2 at four sites simultaneously during stroke. This oximetry approach can be used to test and develop interventions to rescue ischemic tissue by modulating cerebral pO2 during stroke. 相似文献50.
Sattar FA Ahmed F Ahmed N Sattar SA Malghani MA Choudhary MI 《Natural product communications》2012,7(2):195-196
A controlled study was conducted to determine the efficiency of a topical ointment prepared from the stem extract of Morinda citrifolia against cutaneous leishmaniasis. Similarly, the in vitro antileishmanial activity of morindicone and morinthone isolated from the extract were investigated against Leishmania major. These compounds displayed good activity. Out of 40 patients, 50% showed an excellent response and 30% exhibited good improvement. 相似文献