bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of operating conditions on particle size in sonocrystallization
Authors: Oubani Hussein , Abbas Ali , Srour Mourtada , Romagnoli Jose A. 
Published: May 2010

AbstractThis work presents systematic investigations on sonocrystallization to elucidate the effects of key variables on sonocrystallization product properties. A novel continuous flow sonocrystallization apparatus was used to prepare NaCl microparticles from a NaCl–ethanol–water antisolvent system. By implementing a full factorial experimental design, we investigated the effects of ultrasonic power (75–225 W), antisolvent feed rate (0.5–6.5 l/h), system flow rate (2.8–4.1 l/min) and sonication time (5–30 min) on product crystal size. Data from these experiments were regressed to develop an empirical model that was found to be in agreement with experiments. The model identified the interaction between sonication power and system flow to be rather significant. Model simulations found that particle size decreases when antisolvent feed rate or ultrasonic power increases. This was found to be in contrast to increasing the system flow which resulted in larger particle sizes. The regression model was subsequently used to determine optimal operating conditions that minimize mean size, as smaller sizes are commonly required for pharmaceuticals such as for inhalation particles. These optimal values were found to be as follows: antisolvent flow rate = 6.5 l/h, power ultrasound = 225 W, system flow = 2.8 l/min and sampling time = 15 min. The optimal mean size predicted at these conditions was 28.6 ± 5.7 µm which is very close to the observed value of 27.6 µm. A high‐speed camera was used to visualize the ultrasonic irradiation in the sonoreactor and was crucial in explaining the significant interactive effect of sonication power and system flow on crystal size. Copyright © 2010 Curtin University of Technology and John Wiley & Sons, Ltd.
Effect of sodium chloride on the formation and stability of n‐dodecane nanoemulsions by the PIT method
Authors: Liew Jeffery Chin Long , Nguyen Q. Dzuy , Ngothai Yung 
Published: May 2010

AbstractThis paper provides a fundamental study of the effect of sodium chloride on the formation and stability of n‐dodecane/nonionic surfactant (Brij30)/NaCl nanoemulsions produced by the phase inversion temperature (PIT) method. Nanoemulsions are an emulsion system containing droplets from 20 to 200 nm and widely used in cosmetics and pharmaceutical industries. The PIT method was chosen due to its low energy and surfactant usage to produce the nanoemulsions by heating and quenching an emulsion system. The changes of conductivity with temperatures were continuously monitored to determine phase inversion, and are found to be the same in low surfactant concentrations. PIT point was found to decrease with NaCl concentration especially from 5 to 7 wt% Brij30. At the storage temperature (20 °C), the initial droplet size decreases with NaCl concentration; however, the decrement only occurs from 4 to 7 wt% Brij30 while no nanoemulsions can be produced at 8 wt%. By adding salt, the surfactant concentration needed for the most stable nanoemulsions is reduced to 6 wt% from 7 wt%. Therefore, similar stable nanoemulsions can be produced with less surfactant in a brine system. Furthermore, most of the ageing brine‐continuous nanoemulsions could be reproduced to their freshly prepared state by heating process but not for the most stable nanoemulsions. Copyright © 2010 Curtin University of Technology and John Wiley & Sons, Ltd.
Preparation of bioadsorbents for effective adsorption of a reactive dye in aqueous solution
Authors: Ibrahim Shariff , Shuy Wan Zhi , Ang Ha‐Ming , Wang Shaobin 
Published: May 2010

AbstractThe surface of barley straw, an agricultural waste, was modified chemically using a cationic surfactant hexadecylpyridinium chloride monohydrate (CPC) and used as an adsorbent for removal of Reactive Blue 4 (RB4) from aqueous solution. The raw and surfactant‐modified barley straws (SMBS) were characterized by Fourier transform infrared and elemental analysis. The stability of CPC adsorbed on straw surface was evaluated by exposing to water and organic solvents. The adsorption was performed on removing RB4 from wastewater in a batch adsorption system. The effects of contact time, initial concentration of dye and pH of solution on RB4 uptake were investigated and discussed. It was found that the removal percentage of RB4 increased with the increase in contact time. Adsorption was favorable at acidic condition and the maximum removal of 100% was obtained at pH 3. Dye‐loaded SMBS was stable and percentage of desorption was less than 7% in water. The kinetic studies revealed that the kinetic data fitted well to the pseudo‐second‐order model. The isotherm study also indicated that RB4 adsorption on SMBS matched well with the Langmuir model other than the Freundlich model. The maximum adsorption capacity determined from the Langmuir isotherm was 29.2 mg g−1 at 25 °C. Copyright © 2010 Curtin University of Technology and John Wiley & Sons, Ltd.
Silver‐Catalyzed Benzylation and Allylation of Tertiary Alkyl Bromides with Organozinc Reagents
Authors: Mitamura Yukihiro , Asada Yoshihiro , Murakami Kei , Someya Hidenori , Yorimitsu Hideki , Oshima Koichiro 
Published: May 2010

AbstractSilver salts catalyze the benzylation and allylation of tertiary alkyl bromides with organozinc reagents. The reactions create quaternary carbon centers efficiently. Treatment of gem‐dibromoalkanes with benzylic or allylic zinc reagents under silver catalysis leads to dibenzylation or diallylation. The functional‐group compatibility of the present reactions is wider than that of the previous reactions with Grignard reagents.
Neueste Entwicklungen beim baulichen Brandschutz von Straßentunneln
Authors: Friebel Wolf‐Dieter , Blosfeld Jürgen , Kaundinya Ingo 
Published: May 2010

AbstractIn der jüngeren Vergangenheit hat sich gezeigt, dass Straßen tunnel durch größere Brände in erheblichem Umfang geschädigt werden können. In der Folge wurden verschiedene internationale Forschungsprojekte durchgeführt, um den baulichen Brandschutz von Straßentunneln weiterzuentwickeln. Aufbauend auf den internationalen Forschungsprojekten wurden vom BMVBS und der BASt drei nationale Forschungsprojekte zum baulichen Brandschutz von Straßentunneln initiiert. In diesen Projekten wurden vorhandene Temperatur‐Zeit‐Verläufe (sog. “Brandkurven”) für Straßentunnel, Brandver suche in Tunneln und reale Brände in Straßentunneln im Hinblick auf eine mögliche Anwendung zur Bemessung des baulichen Brandschutzes von Straßentunneln analysiert. Außerdem wurden die Temperatureindringung in die Tunnelinnenschale und die Tragfähigkeit von üblichen Tunnelquerschnitten infolge Brandeinwirkung numerisch ermittelt. Schließlich wurde anhand von Brandversuchen an großmaßstäblichen Probekörpern die Wirkung von PP‐Faserbeton auf das Abplatzverhalten von Innenschalenbeton untersucht. Über das Vorgehen und die Ergebnisse dieser Forschungsprojekte wird im Folgenden berichtet.Latest developments for structural fire protection of road tunnels. In the recent past it was shown that road tunnels can be damaged severely by large fires. For that reason several international research projects were carried out for further development of structural fire protection of road tunnels. Based on international research projects three national research projects were initiated by the Federal Ministry of Transport, Building and Urban Development (BMVBS) and the Federal Highway Research Institute (BASt). In the course of these projects existing temperature‐time‐progressions (so called ”fire curves”) for road tunnels, fire tests in tunnels and real fires in road tunnels were analyzed with regard to a possible application for the design of structural fire protection of road tunnels. Furthermore the temperature penetration in the tunnel lining and the load bearing capacity of usual tunnel sections were numerically examined under fire influence. Finally the influence of fiber‐modified concrete on the effect of explosive spalling was investigated by means of large scale fire tests on specimens made of concrete for tunnel lining. In the following procedures and results of the national research projects are described.
Bemessungsnomogramme für Stahlbetonkonsolen
Authors: Schwitzke Marko , Freyer Thomas , Semmler Christin 
Published: May 2010

AbstractIn diesem Beitrag werden Nomogramme für die Bemessung von Stahlbetonkonsolen vorgestellt. Basierend auf den entsprechenden Bemessungsmodellen kann für eine gegebene Stahlbetonkonsole und eine Beanspruchung die Bewehrungsmenge des Zuggurts bestimmt werden. In den Nomogrammen sind alle relevanten Anwendungsgrenzen eingearbeitet. Die Praxistauglichkeit der Nomogramme wird anhand eines Beispiels erläutert.Support for the analysis by concrete brackets. In this contribution nomograms are introduced for the structural analysis of concrete brackets. Based on the appropriate design codes the reinforcement for the tension strut can be determined. In these nomograms all relevant limitations are incorporated. The application of the nomograms is shown using an example.
Validation of a differential in situ perfusion method with mesenteric blood sampling in rats for intestinal drug interaction profiling
Authors: Brouwers Joachim , Mols Raf , Annaert Pieter , Augustijns Patrick 
Published: May 2010

AbstractThe present study explored the feasibility of a differential setup for the in situ perfusion technique with mesenteric cannulation in rats to assess drug interactions at the level of intestinal absorption. In contrast to the classic, parallel in situ perfusion setup, the differential approach aims to identify intestinal drug interactions in individual animals by exposing the perfused segment to a sequence of multiple conditions. First, the setup was validated by assessing the interaction between the P‐glycoprotein (P‐gp) inhibitor verapamil and the transport probes atenolol (paracellular transport), propranolol (transcellular) and talinolol (P‐gp mediated efflux). While transport of atenolol and propranolol remained constant for the total perfusion time (2 h), a verapamil‐induced increase in talinolol transport was observed within individual rats (between 3.2‐ and 5.2‐fold). In comparison with the parallel setup, the differential in situ perfusion approach enhances the power to detect drug interactions with compounds that exhibit strong subject‐dependent permeability. This was demonstrated by identifying an interaction between amprenavir and ketoconazole (P‐gp and CYP3A inhibitor) in five out of seven rats (permeability increase between 1.9‐ and 4.2‐fold), despite high inter‐individual differences in intrinsic permeability for amprenavir. In combination with an increased throughput (up to 300%) and a reduced animal use (up to 50%), the enhanced power of the differential approach improves the utility of the biorelevant in situ perfusion technique with mesenteric blood sampling to elucidate the intestinal interaction profile of drugs and drug candidates. Copyright © 2010 John Wiley & Sons, Ltd.
Purification and characterization of a superoxide dismutase from Panax ginseng
Authors: Li Hong Y. , Zhao Yu , Cao Yang , Wang Wei N. , Zhao Da Q. 
Published: May 2010

AbstractA superoxide dismutase (SOD) with the molecular weight of 31,079 has been purified as a homodimer from Panax ginseng by employing neutral pH buffer extraction, ammonium sulfate precipitation, isoelectric point precipitation and ion exchange methods. The enzyme's specific activity determined by an improved Marklund method was 9480.43 U/mg. Metal analysis showed that the SOD contained iron with the stoichiometry of 0.9 ± 0.3 Fe/subunit and exhibited high thermal stability (70°C) over the pH range from 4.0 to 9.0. Its maximum absorption wavelength was 278 nm and it was sensitive to hydrogen peroxide, trichloromethane‐ethanol and urea. These results indicate that the enzyme is an iron SOD. Copyright © 2010 John Wiley & Sons, Ltd.
Enantioseparation of rabeprazole and omeprazole by nonaqueous capillary electrophoresis with an ephedrine‐based ionic liquid as the chiral selector
Authors: Ma Zheng , Zhang Lijuan , Lin Lina , Ji Ping , Guo Xingjie 
Published: May 2010

AbstractAn ephedrine‐based chiral ionic liquid, (+)‐N,N‐dimethylephedrinium‐bis(trifluoromethanesulfon)imidate ([DMP]+[Tf2N]‐), served as both chiral selector and background electrolyte in nonaqueous capillary electrophoresis. The enantioseparation of rabeprazole and omeprazole was achieved in acetonitrile–methanol (60:40 v/v) containing 60 mm[DMP]+[Tf2N]‐. The influences of separation conditions, including the concentration of [DMP]+[Tf2N]‐, the electrophoretic media and the buffer, on enantioseparation were evaluated. The mechanism of enantioseparation was investigated and discussed. Ion‐pair interaction and hydrogen bonding may be responsible for the main separation mechanism. Copyright © 2010 John Wiley & Sons, Ltd.
Purification of resveratrol, arachidin‐1, and arachidin‐3 from hairy root cultures of peanut (Arachis hypogaea) and determination of their antioxidant activity and cytotoxicity
Authors: Abbott Julie A. , Medina‐Bolivar Fabricio , Martin Elizabeth M. , Engelberth Abigail S. , Villagarcia Hector , Clausen Edgar C. , Carrier Danielle J. 
Published: May 2010

AbstractAntioxidant stilbenoids, such as resveratrol, arachidin‐1, and arachidin‐3, have demonstrated beneficial effects on human health. Although resveratrol is commercially available, arachidin‐1 and arachidin‐3 are not, resulting in an opportunity to explore purification methods and to confirm biological activity. Recently, Arachis hypogaea hairy root cultures (produced via Agrobacterium rhizogenes‐mediated transformation) were reported to secrete stilbenoids into liquid growth media upon elicitation in quantities sufficient for commercial production. The purpose of this study was to purify substantial quantities of resveratrol, arachidin‐1, and arachidin‐3 from A. hypogaea hairy root cultures using centrifugal partition chromatography (CPC), determine the antioxidant activity of these compounds using the thiobarbituric acid reactive substances (TBARS) assay, and determine the cytotoxicity of the compounds using the 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay. In a single run of CPC, resveratrol, arachidin‐1, and arachidin‐3 were separated to a purity of 97.1%, 97.0%, and 91.8%, respectively. Lipid oxidation was inhibited by a 27 and 7 μM dose for reference standards of resveratrol and arachidin‐1, respectively, while oxidation was not inhibited up to a 27 μM dose for reference standard of arachidin‐3. Oxidation was inhibited at a 14, 7, and 14 μM doses for CPC‐purified resveratrol, arachidin‐1, and arachidin‐3, respectively. Arachidin‐1 and arachidin‐3 demonstrated cytotoxicity at 27 and 55 μM in RAW 264.7 and HeLa cell lines, respectively; while resveratrol exhibited no cytotoxicity to either cell line. These results demonstrate the integration of a production and purification system for the manufacturing of A. hypogaea‐derived stilbenoids. © 2010 American Institute of Chemical Engineers Biotechnol. Prog., 2010
Adsorption of Norfloxacin from Aqueous Solution onto Modified Coal Fly Ash
Authors: Zhang C. L. , Li B. Y. , Wang Y. 
Published: May 2010

AbstractBatch adsorption experiments were carried out for the removal of norfloxacin from aqueous solution using modified coal fly ash as adsorbent. The effects of various parameters such as contact time, initial solution concentration and temperature on the adsorption system were investigated. The optimum contact time was found to be 100 min. The equilibrium experimental data can be well fitted by the Freundlich model. Thermodynamic parameters such as ΔG, ΔH and ΔS were also calculated. The negative Gibbs free energy change and enthalpy change indicated the spontaneous and exothermic nature of the adsorption, and the negative entropy change indicated that the adsorption process was aided by decreased randomness.
Inorganic Precipitated Silica Gel. Part 2: Fragmentation by Mechanical Energy
Authors: Quarch K. , Durand E. , Kind M. 
Published: May 2010

AbstractPrecipitated silica (SiO2) is industrially produced by mixing a silicate solution with acid in a semi‐batch process. Polycondensation of monomeric silica leads to the formation of particles which aggregate and eventually form a particulate gel. However, this is instantly fragmented by the mechanical energy input caused by the stirrer. Shrinkage and compaction of these fragments lead to the final product aggregates. It is the aim of this study to enable tailoring of the structure and size of these product particles via the process parameters. In the present paper this is achieved by varying the stirrer speed. It can be shown that there is an analogy between the behavior of the gel and that of highly viscous liquids. Unexpectedly, however, the fragment size can not be reversibly controlled by the power input. The influence of the process parameters on the strength of the gel has been described in the first part of this series [1].
Characterization of organic‐coated solids isolated from different oil sands
Authors: Adegoroye Adebukola , Wang Louxiang , Omotoso Oladipo , Xu Zhenghe , Masliyah Jacob 
Published: May 2010

AbstractSolids isolated from weathered oil sands ores and those having low‐ and high‐fine solids content were studied. The organic matter (OM) adsorbed on the solids was found insoluble in most common solvents, contributing significantly to the change of solid surface properties. The surface properties of these solids were found to affect the entire process cycle of obtaining synthetic crude oil from surface‐mined oil sands using a water‐based extraction process, and managing the existing tailings ponds. In this study, the low‐fine solids ore possessed the lowest amount of organic‐coated solids and highest bitumen recovery. Siderite and pyrite, which tend to concentrate in the hydrocarbon phase were observed in the isolated solids from the weathered and high‐fine ores but were absent in the low‐fine ores. In all the ores studied, the solids from the bitumen froth possess less quartz, and more carbonates compared with solids from the tailings. Elemental analysis by energy dispersive X‐ray spectroscopy (EDX) and elemental analyser revealed the presence of more transition metals (iron and titanium), and carbon in the solids obtained from the bitumen froth when compared with those from the tailings. Infrared (IR) spectroscopy study substantiated the results obtained by X‐ray diffraction and elemental analysis. IR spectra showed a likely association between OM and carbonates in the organic‐coated solids isolated from bitumen froth. More organic‐coated solids were found in weathered oil sands than in other types of ores and observed to reduce bitumen recovery from oil sands.
Destabilisation of homogeneous bubbly flow in an annular gap bubble column
Authors: Al‐Oufi Fahd M. , Cumming Iain W. , Rielly Chris D. 
Published: May 2010

AbstractExperimental results are presented to show that there are very significant differences in the mean gas void fractions measured in an open tube and a annular gap bubble column, when operated at the same gas superficial velocity, using a porous sparger. Measurements were carried out in a vertical 0.102 m internal diameter column, with a range of concentric inner tubes to form an annular gap, giving diameter ratios from 0.25 to 0.69; gas superficial velocities in the range 0.014–0.200 m/s were investigated. The mean gas void fraction decreases with increasing ratio of the inner to outer diameter of the annular gap column and the transition to heterogeneous flow occurs at lower gas superficial velocities and lower void fractions. Two reasons are proposed and validated by experimental investigations: (1) the presence of the inner tube causes large bubbles to form near the sparger, which destabilise the homogeneous bubbly flow and reduce the mean void fraction; this was confirmed by deliberately injecting large bubbles into a homogeneous dispersion of smaller bubbles, and (2) the shape of the void fraction profiles changes with gap geometry and this affects the distribution parameter in the drift‐flux model. Both of these effects serve to reduce the mean gas void fraction in an annular gap bubble column compared to an open tube at the same gas superficial velocity.
Phase distributions in a gas–liquid–solid circulating fluidized bed riser
Authors: Razzak S. A. , Barghi S. , Zhu J.‐X. 
Published: May 2010

AbstractThe distributions of the three phases in gas–liquid–solid circulating fluidized beds (GLSCFB) were studied using a novel measurement technique that combines electrical resistance tomography (ERT) and optical fibre probe. The introduction of gas into a liquid–solid circulating fluidized bed (LSCFB), thus forming a GLSCFB, caused the increase of solids holdup due to the significantly decreased available buoyancy with the lower density of the gas, even with a somewhat increased liquid velocity due to the decreased liquid holdup giving space for the gas holdup. The gas passed through the riser in the form of bubbles, which tended to flow more through the central region of the riser, leading to more radial non‐uniformity in radial holdup of the phases. The gas velocity has the most significant effect on the gas phase holdup. While the gas velocity also has an obvious effect to the solids holdups, the liquid flow rate had a much more considerable effect on the phase holdups. The solids circulation rate also had a significant effect on the phase holdups, with increasing solids circulation rate causing much more increased solids holdup in the central region than close to the wall. A correlation was developed for the relative radial distributions of solids holdup in GLSCFB, as such radial profiles were found similar over a wide range of operating conditions, like those in a typical gas–solid circulating fluidized beds (GSCFB). Finally, the axial solids profiles in a GLSCFB was found to be much closer to those in an LSCFB which are very uniform, than those found in a GSCFB which are less uniform and sometime having a S shape. Water was used as the continuous and conductive phase, air was the gas phase and glass bead and lava rock particles were used as the solid and non‐conductive phase.
A net draft tube slurry airlift bioreactor for 2,4‐D (2,4‐dichlorophenoxyacetic acid) pesticide biodegradation
Authors: Znad H. , Ohata H. , Tade M. O. 
Published: May 2010

AbstractBiodegradation of the pesticides 2,4‐D have been investigated in a net draft tube airlift bioreactor at different concentrations (10–160 ppm) and air flow rates (0.75–4 L min−1), employing acclimatised activated sludge. A modification for the glass draft tube airlift bioreactor was proposed in which the draft tube is made of non‐woven polypropylene textile net. The experiments were carried out as well in a bubble column (BC) for comparison. The results confirmed that immobilising the activated sludge on the net of the draft tube could enhance the substrates mass transfers and improve the biodegradation rate. A mathematical model was developed to simulate the biodegradation process. The simulated results were in good agreement with the experiments.
The effect of Pd‐catalyst wettability on hydrogenation of nitrate to hydroxylamine
Authors: Grote Claudia , Rosu Marius , Schumpe Adrian 
Published: May 2010

AbstractIn the HPO process of the DSM, nitrate is reduced to hydroxylamine on Pd/C catalyst in a 5 M salt solution. Pd/C catalyst increases the interfacial area by a coalescence hindering effect. Nevertheless, mass transfer limitation is encountered and Pd/C catalyst in the liquid bulk is not just useless but even catalyses product decomposition. In this study, the more selective Pd/Al2O3 catalyst was silanised with trichloromethyl silane to reduce its wettability and enrich the catalyst at the gas–liquid interface. The silanization did not affect the catalyst activity. In a stirred tank reactor, significantly higher hydrogen absorption rates were achieved for a flat interface but the effect decreased at higher stirring speed.