bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of geometric variations on the performance of gas dispersion impellers with semicircular blades
Authors: Fasano Julian B. , Myers Kevin J. , Janz Eric E. 
Published: February 2011

AbstractThe effects of impeller blade width and blade number on the gas dispersion behaviour of disc impellers with semicircular blades have been characterised. Increasing blade width or number increases the ungassed turbulent power number and reduces the drop in power draw upon gassing. While speed and power required for gas dispersion decrease with increasing blade width and number, the dispersion torque is relatively independent of these impeller geometric characteristics. A three‐blade impeller exhibits the worst gas dispersion characteristics, while a four‐blade impeller with non‐uniform blade spacing outperforms a four‐blade impeller with uniform blade spacing.
Biosorption of lead(II) from aqueous solution on glutaraldehyde cross‐linked chitosan beads
Authors: Suguna M. , Siva Kumar N. , Subba Reddy A. , Boddu V. M. , Krishnaiah A. 
Published: February 2011

AbstractThe ability of glutaraldehyde cross‐linked chitosan beads (GCC beads) as synthetic adsorbent for adsorptive removal of Pb(II) ions from aqueous solutions is investigated in the present study. The biosorbent has been characterised by Brunner, Emmett, and Teller (BET) analysis, Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) techniques. Equilibrium and column flow adsorption characteristics of Pb(II) ions on the biosorbent were studied. The effects of experimental variable parameters such as pH, concentration of metal ion, amount of adsorbent, contact time, temperature and interfering ions on adsorption have been investigated. The equilibrium data are fitted to pseudo‐first order, pseudo‐second order, fractionary order, chemisorption, Weber–Morris and Boyd models. Based on R2 and error function values, it is observed that the kinetic data are better fitted to pseudo‐second‐order kinetic model and chemisorption model. The experimental data are analysed using Langmuir, Freundlich, and Sips adsorption isotherm models. The monolayer adsorption capacity of GCC beads as obtained from Langmuir isotherm at 35°C is found to be 204.0 mg/g. The thermodynamic constants of the adsorption process: ΔH0, ΔS0 and ΔG0 are evaluated. The results show that biosorption of Pb(II) ions on GCC beads are endothermic and spontaneous.
Decreasing the peroxide decomposition in the magnesia slurry
Authors: Wekesa Moses , Ni Yonghao 
Published: February 2011

AbstractThe peroxide bleaching process for mechanical pulps using weak alkali sources such as magnesium hydroxide (Mg(OH)2), received much attention recently. The magnesia slurry (containing 61.2% Mg(OH)2) can be used for this purpose. In this paper, we studied the manganese‐induced peroxide decomposition in commercial magnesium hydroxide slurry (magnesia). The results showed that peroxide decomposition occurs under the conditions of magnesia based bleaching process. This is due to impurities, particularly manganese in the magnesia slurry. Similar to the conventional sodium hydroxide based process, sodium silicate can effectively decrease the manganese‐induced peroxide decomposition. However, the amount of silicate required is significantly less. It was found that diethylenetriaminepentaacetic acid (DTPA) or its sodium salt, can also be an effective stabiliser in the system. The chemistry of the manganese‐induced peroxide decomposition was discussed.
Experimental investigation of column efficiency for two ternary systems in a three‐phase packed distillation column
Authors: Torkmahalleh M. Amouei , Rahmati M.M. Montazer , Haghi B. Nematdoost 
Published: February 2011

AbstractIn this work, the effect of vapor load and initial feed concentrations on column efficiency and liquid hold‐up in a two‐ and three‐phase packed distillation column at total reflux was investigated. Results for the two investigated mixtures (n‐heptane, n‐hexane, water) and (ethyl acetate, 1‐butanol, water) reveal that column efficiency remains almost constant for the former mixture but changes significantly for the latter. Specific liquid hold‐up and water to organic‐phase volumetric ratio within the column affect the column efficiency due to variations in initial feed concentrations. Influence of vapor load on separation efficiency and specific liquid hold‐up is also studied.
Comparison of mixing index for binary and ternary mixtures of irregular particles in a gas–solid fluidized bed
Authors: Sahoo A. , Garg R. K. , Roy G.K. 
Published: February 2011

AbstractTernary mixtures of equi‐density particles have been fluidized in a gas–solid fluidized bed to study the mixing characteristics. A correlation for the mixing index has been developed for these mixtures. The mixing index for the ternary mixtures has also been calculated by the already available method. Finally a comparison has been made for the values of the mixing index calculated by both the methods against the experimental ones. The values of the mixing index for the ternary mixtures thus obtained have also been compared with those of the binary mixtures thereby indicating its application for real life multi‐component mixing over a wide range of parameters.
Process energy efficiency in pervaporative and vacuum membrane distillation separation of 2,3‐butanediol
Authors: Shao Pinghai , Kumar Ashwani 
Published: February 2011

AbstractThis work focused on the energy aspects of the pervaporative separation of 1‐butanol/2,3‐butanediol. A numeric model was developed to simulate the mass and energy balance of the pervaporation process. It was found that the distribution of evaporation heat requirement over the membrane area is asymmetric, and more than 85% of the heat was consumed in the 60% of the membrane area. It was also revealed that recycling the permeate having higher than 5% w/w 2,3‐butanediol can improve the recovery of 2,3‐butanediol, and thus enhance the process energy efficiency. Two recycling strategies (the single or multiple point admission of permeate to the retentate flow) were explored. The specific energy requirement (the heat required by generating 1 kg 99.5% w/w 2,3‐butanediol as product) was proposed to evaluate the process energy efficiency of both the pervaporation and vacuum membrane distillation, and it was shown that pervaporation can bring about nearly four times energy savings over the vacuum membrane distillation.
Near wall effects in the plug flow of pulp suspensions
Authors: Fock Helena , Claesson Julia , Rasmuson Anders , Wikström Tomas 
Published: February 2011

AbstractExperimental data by the authors are further analysed to gain a more detailed understanding of the mechanisms of the plug flow and near‐wall behaviour in the pipe flow of pulp suspensions at concentrations up to 4.7% by weight. The results indicate two‐phase flow effects near the wall, one being that the apparent viscosity is higher than that of water. Another is that the wall shear stress estimated with the pressure drop data and a force balance is much higher than the one obtained with the measured velocity profile, indicating the presence of mechanical friction forces.
Mathematical analysis of effects on the electrostatic double layer of nanoscale surfaces in microfluidic channels
Authors: Aston D. E. , Berven C. A. , Williams B. C. , Basu A. 
Published: February 2011

AbstractThe effects of microfluidics on the electrostatic double layer (EDL) of a nano‐structured electrode are investigated through numerical modelling. The parameters of interest are the height and spacing of nanostructures, specifically, nanowire and “nanopillar” pairs rising from an idealised sensor substrate perpendicular to the fluid flow. A direct comparison of the EDL thicknesses at the peaks and valleys of this nanostructure are reported for variations in fluid velocity, nanowire spacing, and height under fixed conditions of combined pressure‐driven and electro‐osmotic driving forces. In a microchannel based on the Navier–Stokes and Helmholtz–Smoluchoswki flow models, numerical simulations provide insight into the practical design of chemically selective nanomaterial electrodes for potentiometric detection of ions in water.
CFD simulation of free liquid surface motion in a pilot plant stirred tank
Authors: Jahoda M. , Moštěk M. , Fořt I. , Hasal P. 
Published: February 2011

AbstractThe Volume of Fluid method together with the Large Eddy Simulation technique for turbulence flow was used for CFD prediction of liquid flow and free liquid surface motion in a pilot plant cylindrical flat‐bottomed stirred tank with an inner diameter of 1 m filled with tap water at room temperature. A pitched‐blade (45°) down pumping impeller (diameter of 0.33 m) with six blades was used for stirring. The impeller speed was 180 rpm. For simulation of the impeller motion, the sliding mesh method was adopted. The CFD simulations of the flow field predicted a highly complex, multi‐dimensional dynamic system exhibiting unstable, pseudo‐stationary behaviour. The main advantage of this CFD simulation is the prediction of the velocity flow patterns and the free surface elevation/depression in the whole system at one time. The results for the location and dimensions of the free liquid surface fluctuation correspond well with an experimental investigation by a conductivity method.
Theoritical analysis and simulation of five‐zone simulating moving bed for ternary mixture separation
Authors: Khan H. , Younas M. 
Published: February 2011

AbstractIn the present work a mathematical model has been presented to study the behaviour of five‐zone simulating moving bed (SMB) system for the separation of a ternary mixture of certain amino acids. These are methionine, phenylalanine and tryptophan, possessing linear isotherms values. Safety margin method has been used to design the SMB system while triangle theory became the basis to calculate the operating conditions at fixed feed flow rate. It was found that for same safety factor (β) value in each zone, increase in β value causes the purity values of all product streams to increase up to a definite value. Further increase in β value shows the effect of decrease in separation efficiency, because of dominance of axial dispersion and mass transfer resistances. The effect of zone safety factor (zone flow rate βII, βIII and βIV) values on the separation performance of five‐zone SMB have also been investigated which remained an important issue in SMB current research. Increase in βII value results in rising tryptophan purity, phenylalanine purity improves due to increase in βIII value and increase in βIV value becomes the basis for enhancing methionine purity. In column profile study, the solute concentration profile diminishes due to increase in particular separation zone safety factor value. This happened due to low column switching time with high desorbent flow rate to the system. The developed mode was run in Aspen Chromatography vis 12.1. (2004) simulator for simulation studies.
Synthesis of Amino‐Functionalized Hexagonal Mesoporous Silica for Adsorption of Pb2+
Authors: Wei Kun , Shu Lijun , Guo Wusheng , Wu Yuan , Zeng Xiaofeng 
Published: February 2011

AbstractHighly ordered amino‐functionalized hexagonal mesoporous silica (HMS‐NH2) had been synthesized successfully by co‐condensation. The resultant materials were characterized by means of XRD, TEM, FT‐IR, N2 ad‐desorption and 29Si NMR to confirm the ordered mesoporous structure and the functionalization of the amino groups. The sample was employed as a Pb2+ adsorbent in aqueous solutions at room temperature. Both Lagergren's first order kinetic model and Lagergren's second order kinetic model were used to describe the adsorption data. It was found that the pseudo second order model fitted the sorption kinetic data better than the pseudo first order model. According to the information analyzed from AAS, HMS‐NH2 had a Pb2+ adsorption amount of over 90.7 mg·g−1, showing a promising application for the treatment of wastewater containing Pb2+ ions.
Ultrasonic Extraction Coupled with Capillary Electrophoresis for the Determination of Azo Dyes in Lipsticks Using Ionic Liquid as Dynamic Coating and Background Electrolyte
Authors: Li Dan , Wang Ziming , Wang Lu , Xu Xu , Zhang Hanqi 
Published: February 2011

AbstractA simple and rapid method based on ultrasonic extraction and capillary electrophoresis using 1‐butyl‐3‐methylimidazolium tetrafluoroborate as dynamic coating and background electrolyte was developed. The method was applied to the separation and determination of three azo dyes in two lipsticks. To increase extraction rate and yield, lipstick samples were coated on a glass slide before ultrasonic extraction. The dyes were extracted by ultrasonic extraction for 30 min, and then determined by capillary electrophoresis. Several experimental factors, such as ionic liquid concentration, pH value of background electrolyte and applied voltage, were examined and optimized. Under the optimal conditions, three azo dyes were completely separated within 12 min, and the detection limits for the three azo dyes ranged from 0.33 to 0.88 μg/mL. The recoveries were in the range of 96.8% to 108.8%.
Proteomics Analysis of T Lymphocytes Damage Induced by Ionizing Irradiation
Authors: Shi Ying , Zhang Xuan , Liu Ning , Liang Feng , Song Fengrui , Liu Zhiqiang , Liu Shuying 
Published: February 2011

AbstractHuman T lymphocytes were found to be highly radiosensitive and complex cellular responses including apoptosis could be induced upon exposure to X‐ray irradiation. However, the mechanism of apoptosis associated with irradiation was not clear. In this study, a proteomic method was applied to investigation on alteration of proteome of human T‐lymphocyte cells after irradiation. The Jurkat cells were irradiated with 4 Gy X‐ray and the cell lysates were collected at different times after irradiation (6, 12, 18, 24 and 48 h). The whole proteins were separated and quantified by two‐dimensional fluorescence difference gel electrophoresis, and then the differentially expressed proteins were identified by mass spectrometry. 4 proteins exhibited significant irradiation‐induced difference in abundance, including L‐plastin, bifunctional purine biosynthesis protein, tubulin beta chain, beta‐actin. Differentially expressed proteins were reported to be directly or indirectly involved in the function of human T lymphocyte. Thus, this study might provide clues to identify proteins with biological significance related to irradiation.
Syntheses, Structures and Properties of Four Manganese Coordination Polymers Derived from 4‐Amino‐3,5‐bis(imidazol‐1‐ylmethyl)‐1,2,4‐triazole
Authors: Feng Yunfei , Yuan Deyun , Wang Ju , Li Baolong , Li Haiyan 
Published: February 2011

AbstractThe reaction of 4‐amino‐3,5‐bis(imidazol‐1‐ylmethyl)‐1,2,4‐triazole (abit) and manganese(II) salts yields four coordination polymers {[Mn(abit)3](ClO4)2}n (1), {[Mn(abit)3](PF6)2}n (2), [Mn(abit)(dca)2(H2O)2]n (3a) and [Mn(abit)(dca)2(H2O)2]n (3b). Compounds 1 and 2 are one‐dimensional triple‐stranded chain. Compounds 3a and 3b are polymorphous and construct one‐dimensional single chain. The conformational analysis is performed. The thermal properties have been investigated.
Facile Synthesis of Multi‐Branched Gold Nanostructures through a TBAB‐Assisted Route in Aqueous Solution and Their SERS Property
Authors: Wang Luyan , Wu Xinzhou , Pei Meishan , Wu Zhiyan , Li Xiaonan , Tao Xutang 
Published: February 2011

AbstractFacile synthesis of multi‐branched gold nanostructures by using the tetrabutyl ammonium bromide (TBAB) as a capping agent is described. The reaction is carried out in a one‐step process at mild temperature. Gold nanostructures with more than six sharp branches ranging from 70 to 130 nm in length are synthesized in high yield. It is proposed that the relative weak adsorption capacity of TBAB leads to the incompletely covered gold surface and the growth of nanoparticles occurs on the uncovered gold surface, and therefore short branches appear consequently. Then positively charged TBAB layers on the gold surfaces prevent the branches from aggregating with each other which stimulates the branch growth. The prepared branched gold nanoparticles show efficient surface‐enhanced Raman scattering (SERS) properties. Low temperature (4°C) is unfavorable to the formation of multi‐branched gold nanostructures, and only thin small irregular plate‐like nanoparticles are produced. The addition of SDS in TBAB aqueous solution results in forming SDS micelles at much lower concentration of SDS (0.4 mmol/L) as compared to that in pure water, and short branched gold nanoparticles are obtained in the SDS‐TBAB system.
Controlled‐growth of Zn(OH)F Microbesoms in the Mild Aqueous Solution and Their Photocatalytic Activity
Authors: Peng Ying 
Published: February 2011

AbstractZn(OH)F microbesoms have been synthesized on a large scale by a facile solution‐based method using polymer as crystal growth modifier. The obtained products were characterized by X‐ray powder diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). The effects of modifier polyacrylamide (PAM), reaction time, concentrations of NaF on the morphology and size of the product were studied. The results revealed that the Zn(OH)F microbesom had orthorhombic structures. Experimental conditions had all influence on the shape and size of the final products, but polymer PAM played the key role in formation of the Zn(OH)F microbesom. This novel structures exhibited good UV photocatalytic abilities.
Asymmetric Direct Aldol Reaction of Cyclohexanone Catalyzed by (N′‐Benzyl‐N′‐D‐prolyl)‐trans‐4‐hydroxy‐L‐proline Hydrazide
Authors: Cheng Chuanling , Wang Wenliang 
Published: February 2011

AbstractA new proline catalyst, namely (N′‐benzyl‐N′‐D‐prolyl)‐trans‐4‐hydroxy‐L‐proline hydrazide, has been prepared and proved to be a superior catalyst for the asymmetric aldol reaction of cyclohexanone and aromatic aldehydes, affording up to 98:2 dr and 98% ee.
Carbon‐Based Solid Acid as An Efficient and Reusable Catalyst for One‐Pot Synthesis of Tetrasubstituted Imidazoles under Solvent‐Free Conditions
Authors: Tavakoli‐Hoseini Niloofar , Davoodnia Abolghasem 
Published: February 2011

AbstractCarbon‐based solid acid catalyst was found to be highly efficient, eco‐friendly and recyclable heterogeneous catalyst for the multicomponent reaction of benzil, aromatic aldehyde, primary amine and ammonium acetate, giving rise to 1,2,4,5‐tetrasubstituted imidazoles in good to excellent yields. The present methodology offers several advantages, such as high yields, short reaction time, mild reaction condition and a recyclable catalyst with a very easy work up.
Preparation of CuS‐P(NIPAM‐co‐MAA) Hybrid Microgels with Controlled Surface Structures
Authors: Zhang Ying , Liu Huijin , Fang Yu 
Published: February 2011

AbstractCopper sulfide‐poly(isopropylacrylamide‐co‐methacrylic acid) [CuS‐P(NIPAM‐co‐MAA)] hybrid microgels with patterned surface structures have been synthesized by means of the polymer microgel template technique. The results showed that the surface morphology of the hybrid microgels could be regulated by controlling the decomposition of thioacetamide (TAA) in an acidic medium. The rate of precipitation and the amount of metal sulfide significantly affect the surface structures of the hybrid microgels.
Investigating the Calculation of Rotational Viscosity of the Mixture Comprising Different Kinds of Liquid Crystals: Molecular Dynamics Computer Simulation Approach
Authors: Kim Jinsoo , Jamil Muhammad , Jung Jae Eun , Jang Jae Eun , Farzana Ahmad , Jin Woo Lee , Sang Woo Park , Woo Min‐Kyung , Kwak Ji Yeon , Jeon Young‐Jae 
Published: February 2011

AbstractMolecular dynamics (MD) computer simulation techniques, as a powerful tool commonly utilized by the liquid crystal display (LCD) community, usually are employed for computing the equilibrium and transport properties of a classical many body system, since they are very similar to real experiments in many respects. In this paper we present molecular dynamics computer simulation results taken for a mixture of the two different kinds of nematic liquid crystals (LCs). We calculated rotational viscosity from Brownian behavior with friction of the mean director of the mixture comprising pentylcyanobiphenol (5CB) and decylcyanobiphenol (10CB) by using molecular dynamics computer simulation, where intermolecular potential parameter is Generalized AMBER force field (GAFF). Our computed results show a good agreement with the experimental results.
Diperoxo Complexes of Vanadium(V) Containing Mannich Base Ligands
Authors: Mahajan Simpy , Singh Balgar , Sharma Mohita , Sheikh H. N. , Kalsotra B. L. 
Published: February 2011

AbstractThe vanadium(V) peroxo complexes containing Mannich base ligands having composition Na[VO(O2)2(L‐L)]·H2O [where L‐L=morpholinobenzyl acetamide (MBA), piperidinobenzyl acetamide (PBA), morpholinobenzyl benzamide (MBB), piperidinobenzyl benzamide (PBB), morpholinomethyl benzamide (MMB), piperidinomethyl benzamide (PMB), morpholinobenzyl formamide (MBF), piperdinobenzyl formamide (PBF)] have been reported. The complexes have been prepared by stirring vanadium pentoxide with excess of 30% aqueous‐H2O2 followed by treatment with ethanolic solution of the ligand and finally maintained the pH of the reaction mixture by adding dilute solution of sodium hydroxide. The synthesized complexes have been characterized by various physico‐chemical techniques, via elemental analysis, molar conductivity, magnetic susceptibility measurements, infra red, electronic, mass, 1H NMR spectral and TGA/DTA studies. These studies revealed that the synthesized complexes are uni‐univalent electrolytes and diamagnetic in nature. The ligands are bound to metal in a bidentate mode through carbonyl oxygen and the ring nitrogen. Thermal analysis result provides conclusive evidence for the presence of one molecule of lattice water in the complexes. Mass spectra confirm the molecular mass of the complexes.
Pyridine‐N‐oxide: An Efficient Organocatalyst for Ring‐Opening Reactions of Aziridines with Aryl Thiols
Authors: Yang Qin , Yin Zhenlan , Yang Min , Peng Yiyuan 
Published: February 2011

AbstractPyridine‐N‐oxide serves as an efficient catalyst for the ring‐opening reactions of N‐tosylaziridines with various aryl thiols under mild conditions. This transformation is highly effective, which gives rise to the corresponding β‐amino sulfides in good to excellent yields.
Improving FRET‐Based Monitoring of Single Chemomechanical Rotary Motors at Work
Authors: Börsch Michael , Wrachtrup Jörg 
Published: February 2011

AbstractProtein dynamics are observable in real time using internal distance measurements of reference positions. Based on Förster resonance energy transfer (FRET) as the distance ruler between two fluorescent markers, investigations of single molecules one at a time have modified our views of protein conformational changes. X‐ray crystallography provides trapped conformations at atomic resolution and NMR can add information about flexible parts of proteins, but the pathways between these structures including unknown conformations are often not directly accessible. Especially for membrane enzymes comprising multiple subunits, limited structural information requires alternative experimental methods to follow conformational pathways. Herein we summarize the knowledge gathered from single‐molecule FRET studies of the membrane‐embedded rotary nanomotor FoF1‐ATP synthase. In addition, new ideas and concepts to shift and extend the current limitations of the confocal FRET detection approach using freely diffusing, liposome‐reconstituted, individual enzymes are discussed: nanodiamonds as new fluorophores, optimized laser excitation schemes, Hidden Markov Models for software‐based FRET trajectory analysis, and application of the anti‐Brownian electrokinetic trap (ABELtrap) to keep the single enzyme in focus.