bluuebunny/crossref_metadata_2025_split huggingface dataset:
The jet shape of concentric mixers
Authors: Giorges Aklilu T. G. , Wang Xiaodong , Forney Larry J. 
Published: March 2009

AbstractIn this paper, we present an analytical and experimental study of the mixing region and jet shape in concentric mixers. Based on a simple but effective analytical model, we are able to predict the growth of the mixing region with respect to downstream distance. An experimental study is conducted on the concentric mixing of paper fibre stock and water. By comparing with experimental results, we confirm that the shape of the mixing region is a practical indicator of mixing efficiency with the consideration of jet velocity and geometry including the nozzle wall thickness.
The effect of non‐ideal mixing on the number of steady states and dynamic behaviour for autocatalytical reactions in a CSTR
Authors: Chien Yu‐Shu 
Published: March 2009

AbstractIn this paper, we analyze the concentration multiplicity and dynamic behavior for an autocatalytical reaction, A + R → (n + 1)R + products with an overall rate expression given by – γa= kcapcrr(p > 0 and r > 0) in a imperfectly mixed (Cholette's model) CSTR. We proved that non‐ideal mixing had an effect on the number of steady states and dynamic behavior for the reaction orders r > 1 and r = 1. However, the above‐mentioned effect does not happen for the reaction order r < 1. Furthermore, a simulated example was used to demonstrate our results.
A Re‐Examination of heat transfer in laminar divergent flow between two parallel fixed discs
Authors: Fahidy Thomas Z. , Cóuret François 
Published: March 2009

AbstractUpon a critical review of pertinent literature, new theoretical expressions for dimensionless heat transfer rates between two parallel fixed circular discs and a fluid in radial divergent laminar flow are established and compared to previously published theory and experimental data. Based on the logarithmic mean temperature difference, the new analytical relationships are shown to adequately predict dimensionless heat transfer rates, and it is recommended that they be used in preference to certain earlier expressions which are either erroneous or of strongly limited applicability.
Modelling oxygen solubility in bleaching solutions
Authors: Tromans Desmond 
Published: March 2009

AbstractA general thermodynamics‐related model of oxygen solubility, previously developed for water and aqueous inorganic solutions, has been applied to bleaching solutions. The model allows estimations of dissolved oxygen concentrations to be made for different combinations of temperature, oxygen partial pressure and inorganic solute concentrations likely to be encountered during oxygen bleaching of pulp. Combination of the model with oxygen diffusion kinetics allows optimum temperatures for transport‐controlled oxygen delignification rates to be estimated.
Diffusion and reactivity of gas oil in FCC catalysts
Authors: Al‐Khattaf Sulaiman , de Lasa Hugo I. 
Published: March 2009

AbstractThis study considers the effects of diffusion and intrinsic catalytic reactivity for the cracking of gas oil on FCC catalysts. A four‐lump kinetic model, initially developed in a novel CREC Simulator, is employed to estimate the unconverted gas oil, the gasoline, the light gases and the coke fractions. The model incorporates a modified Thiele modulus, based on zeolite crystal properties, and an effectiveness factor. The calculated effectiveness factor is found to increase with the gas oil conversion and to decrease with the intrinsic rate constant and the zeolite crystal size. The proposed model predicts that crystal size changes in the 0.13 to 1.3 μm range affect both primary and secondary cracking reactions and the yields of gasoline, coke and light gas yields.
Modelling of trickle‐bed reactors in foaming regime
Authors: Turco Francesco , Hudgins Robert R. , Silveston Peter L. , Sicardi Silvio , Manna Luigi , Banchero Mauro 
Published: March 2009

AbstractHydrogenation of α‐methyl styrene (AMS) to cumene at 40°C in a downflow trickle bed was used as a test reaction for an investigation of the prediction of the performance of trickle‐bed reactors. Dynamic and static saturation are well predicted by several models but pressure drop cannot be accurately estimated by correlations now in the literature. This raises doubts about the use of mass transfer models which employ pressure drop taken from the literature. The simple film model for predicting conversion fails in the high‐interaction regime at least with foaming liquids. A correction to the model to allow for the effect of foam on mass transfer characteristics is proposed but was not independently tested.
An investigation of the effect of air addition during oil sand conditioning
Authors: Flynn Morris , Bara Barry , Czarnecki Jan , Masliyah Jacob 
Published: March 2009

AbstractBitumen aeration was studied by flooding samples of medium grade oil sand with de‐ionized water under both ambient and high vacuum conditions. The samples were then agitated on a shaker table. Subsequent analysis revealed the presence or absence of an air gap in the sample container was the single most important factor in determining the overall bitumen recovery. Furthermore, samples that were flooded while under high vacuum produced slightly less bitumen compared to samples flooded at atmospheric pressure. This suggests that oil sand that is not under high vacuum when flooded with water contains some amount of indigenous air (see introduction) that would aid in bitumen flotation.
Effect of particle tethering and Scale‐Up on solid–liquid mass transfer in Three‐Phase fluidized beds of light particles
Authors: Song Jiasen , Hyndman Caroline L. , Kantzas Apostolos 
Published: March 2009

AbstractSolid–liquid mass transfer in three‐phase fluidized beds with low‐density particles was studied using a tethered benzoic acid particle dissolution technique. Two columns with air, water and polypropylene cylinders were used for experiments. The solid–liquid mass transfer coefficient was found to increase with column diameter but decrease with tether length. The effect of tethering on solid particle movements was also evaluated using radioactive particle tracking (RPT) technique. RPT showed that tethered particles exhibited slower movements. Statistical analysis suggests that tether lengths 3 times the column radius are sufficient to reduce the effects of tethering.
Use of ultrasound for phase holdup measurements in multiphase systems
Authors: Macchi Arturo , Grace John R. , Bi Hsiaotao 
Published: March 2009

AbstractThis study evaluates ultrasound as a non‐invasive technique for determining the cross‐sectional holdups of multiphase systems. Experiments are performed in a column of 292 mm inner diameter with air, water and uniform glass beads of 1.3 mm diameter as the particles. In a bubble column, the signal intensity decayed exponentially with increasing gas holdup. In a liquid–solid fluidized bed, the wave time‐of‐flight decreased linearly when the solids holdup increased from 25% to 60% (fixed bed), while the signal intensity increased. Signal attenuation limits the use of this method for three‐phase fluidized beds. When large particles (mm range) are used, it is difficult to operate at a wavelength that permits transmission through both dispersed phases. For three‐phase systems, slurry bubble columns with low dispersed phases holdups and smaller particles present a less attenuative media and are better suited to this technique.
Cysteine Oxidation by the Superoxide Radical: A Theoretical Study
Authors: Cardey Bruno , Enescu Mironel 
Published: March 2009

AbstractActive molecular environment: Oxidation of the cysteine residue by the superoxide radical (see picture) is studied in the gas phase and in aqueous solution using the integrated molecular orbital+molecular orbital. It is shown that the molecular environment plays an important role in the oxidation of biologically relevant thiol compounds by the superoxide radical.magnified imageThe cysteine residue oxidation by the superoxide radical in the gas phase and in aqueous solution is studied using the integrated molecular orbital+molecular orbital (IMOMO) method combining the quadratic configuration interaction [QCISD(T)] and density functional (DFT) methods. The molecular environment effects are systematically investigated by considering two alternative directions of attack of the superoxide radical on the thiol and two different cysteine residue conformations. It is found that hydrogen bonding and the electrostatic interactions between the superoxide radical and cysteine side chain significantly affect the reaction energy barrier, as compared to that derived for the simple thiol model methanethiol. Among the two possible reaction channels, the one involving the sulfinyl radical formation is predicted to be the dominant channel in aqueous solution. In a highly hydrophobic environment the thiyl radical formation channel becomes the main cysteine oxidation channel.
Chromatin immunoprecipitation in early Xenopus laevis embryos
Authors: Blythe Shelby A. , Reid Christine D. , Kessler Daniel S. , Klein Peter S. 
Published: March 2009

AbstractChromatin immunoprecipitation (ChIP) is a powerful method for analyzing the interaction of regulatory proteins with genomic loci, but has been difficult to apply to studies on early embryos due to the limiting amount of genomic material in these samples. Here, we present a comprehensive technique for performing ChIP on blastula and gastrula stage Xenopus embryos. We also describe methods for optimizing crosslinking and chromatin shearing, verifying antibody specificity, maximizing PCR sensitivity, and quantifying PCR results, allowing for the use of as few as 50 early blastula stage embryos (approximately 5×104 cells) per experimental condition. Finally, we demonstrate the predicted binding of endogenous β‐catenin to the nodal‐related 6 promoter, binding of tagged Fast‐1/FoxH1 to the goosecoid promoter, and binding of tagged Tcf3 to the siamois and nodal‐related 6 promoters as examples of the potential application of ChIP to embryological investigations. Developmental Dynamics 238:1422–1432, 2009. © 2009 Wiley‐Liss, Inc.
Evaluation of the PESERA model in two contrasting environments
Authors: Licciardello F. , Govers G. , Cerdan O. , Kirkby M. J. , Vacca A. , Kwaad F. J. P. M. 
Published: March 2009

AbstractThe performance of the Pan‐European Soil Erosion Risk Assessment (PESERA) model was evaluated by comparison with existing soil erosion data collected in plots under different land uses and climate conditions in Europe. In order to identify the most important sources of error, the PESERA model was evaluated by comparing model output with measured values as well as by assessing the effect of the various model components on prediction accuracy through a multistep approach. First, the performance of the hydrological and erosion components of PESERA was evaluated separately by comparing both runoff and soil loss predictions with measured values. In order to assess the performance of the vegetation growth component of PESERA, the predictions of the model based on observed values of vegetation ground cover were also compared with predictions based on the simulated vegetation cover values. Finally, in order to evaluate the sediment transport model, predicted monthly erosion rates were also calculated using observed values of runoff and vegetation cover instead of simulated values. Moreover, in order to investigate the capability of PESERA to reproduce seasonal trends, the observed and simulated monthly runoff and erosion values were aggregated at different temporal scale and we investigated at what extend the model prediction error could be reduced by output aggregation.PESERA showed promise to predict annual average spatial variability quite well. In its present form, short‐term temporal variations are not well captured probably due to various reasons. The multistep approach showed that this is not only due to unrealistic simulation of cover and runoff, being erosion prediction also an important source of error. Although variability between the investigated land uses and climate conditions is well captured, absolute rates are strongly underestimated. A calibration procedure, focused on a soil erodibility factor, is proposed to reduce the significant underestimation of soil erosion rates. Copyright © 2009 John Wiley & Sons, Ltd.
Wolken, Wind und Niederschlag
Authors: Hense Andreas 
Published: March 2009

AbstractWettervorhersagen sind ein komplexes Unterfangen. Neben immer präziseren Daten fließt auch viel Grundlagenforschung in die Prognosen ein. Die Meteorologen wollen dabei vor allem die Naturerscheinungen in der Atmosphäre noch besser verstehen
Medical students' recognition of elder abuse
Authors: Thompson‐McCormick Jonas , Jones Lisa , Cooper Claudia , Livingston Gill 
Published: March 2009

AbstractObjectivesTo determine the proportion of fourth‐year medical students who correctly recognise abusive and not abusive care of older people and whether recognition is related to sociodemographic factors and education.DesignA cross‐sectional self‐report questionnaire study, using the Caregiving Scenario Questionnaire; measuring recognition of elder abuse according to the Department of Health's definition.ParticipantsFourth‐year medical students at University College London and the University of Birmingham, UK.ResultsTwo hundred and two of 207 students (97.6%) responded. Twenty‐nine of 201 (14.4%) identified accepting someone was not clean; 113/200 (56.5%) locking someone in alone; and 160/200 (80.0%) trapping someone in an armchair as abusive. All medical students correctly identified four out of five not abusive responses. Twelve (6.0%) incorrectly identified camouflaging the door to prevent wandering as abusive. Logistic regression analysis found the independent predictors of recognising that locking in alone was abusive were working as a professional carer (OR = 3.33, 95% CI = 1.25–8.89, p < 0.05) and reporting being taught to look for elder abuse (OR = 0.46, 95% CI = 0.24–0.89, p < 0.05). Similarly, the independent predictors of recognising that restraint in an armchair was abusive were attending university A versus university B (OR = 2.38, 95% CI = 1.09–5.26, p < 0.05); being of White British versus Asian ethnicity (OR = 4.00, 95% CI = 1.75–9.09, p < 0.01).ConclusionsMedical students are good at recognising not abusive care, but not as successful at recognising elder abuse. Working as a professional carer was associated with better recognition of abuse, while personal contact with a person with dementia and recalling formal education about abuse were not. Copyright © 2009 John Wiley & Sons, Ltd.
Temporal characteristics and variability of point rainfall: a statistical and wavelet analysis
Authors: Beecham S. , Chowdhury R. K. 
Published: March 2009

AbstractRainfall characteristics at different temporal resolutions play a significant role in sustainable urban water management. In this study we attempted to identify the temporal characteristics and variability of point rainfall measured in Melbourne, Australia. Statistical moments, lag1 autocorrelation, the Buishand's Q test for homogeneity, the Mann–Kendall (MK) test for trend and wavelet analyses for temporal variability were carried out for rainfall intensities at resolutions of 0.1, 0.5, 1, 3, 6, 12 h and for the monthly rainfall depths and proportion dry ratios. Series of rainfall intensities at different temporal scales and the monthly rainfall depths and proportion dry ratios were accumulated from the high resolution rainfall dataset for the period from 1925 to 2002. Homogeneity of rainfall intensity was found to increase as the temporal scale increases. Both rainfall intensities and monthly rainfall depths were found to be serially correlated. The 2nd, 3rd and 4th statistical moments of rainfall intensities increased as the resolution increased. While no statistically significant trends were found using the MK test, there were indications that trends are more likely as the temporal scale increases. Wavelet power spectra identified a dominant frequency scale (0.25–1 year) in the 3, 6 and 12 h rainfall intensities that were periodically observed in a 5 to 10–year cyclic order. This phenomenon could be influenced by the inter‐annual variability of the El Niño Southern Oscillation (ENSO). Copyright © 2009 Royal Meteorological Society
Impacts of Pacific and Indian Ocean coupling on wintertime tropical intraseasonal oscillation: a basin‐coupling CGCM study
Authors: Weng Shu‐Ping , Yu Jin‐Yi 
Published: March 2009

AbstractThis study examines the respective influences of Pacific and Indian Ocean couplings on tropical intraseasonal oscillation (ISO) in boreal winter (November–April). Three basin‐coupling experiments are performed with a coupled atmosphere‐ocean general circulation model (CGCM), in which air‐sea coupling is limited respectively to the Indian Ocean, the Pacific Ocean, and both the oceans. The modelling results show that zonal ISO propagations can be found in the Indo‐Pacific region with or without the ocean coupling; however, the propagation signals are enhanced by the coupling. In this particular model the Pacific Ocean coupling has a stronger influence on the ISO propagation than the Indian Ocean coupling. Without the Pacific coupling, the ISO propagation signal is weakened significantly when it enters the Pacific Ocean sector. Without the Indian Ocean coupling, the simulated ISO intensity is weakened less in the Indain Ocean, and significant zonal propagations of ISO can still be simulated in the sector. The relative importance of the ocean coupling is likely related to the smaller ISO‐related sea surface temperature (SST) anomalies in the Indian Ocean than in the Pacific Ocean. In this particular CGCM, the ocean coupling affects the ISO propagation mainly through a wind‐evaporation‐SST feedback rather than a cloud‐radiation‐SST feedback, while in observations both processes are equally important. To further confirm the importance of the ocean coupling, forced atmospheric GCM experiments are performed with SSTs prescribed from the climatologies produced in the basin‐coupling experiments. It is found that the eastward propagating feature seen in the CGCM experiments is weakened and dominated by the strong standing feature in the forced AGCM runs. The difference demonstrates the contribution of the ocean coupling to the ISO propagation, and also confirm that biases in the mean SST and low‐level wind caused by the ocean coupling are responsible for the spurious standing ISO oscillation feature in the central Pacific and Indian Oceans. Copyright © 2009 Royal Meteorological Society
Joint‐preserving limb salvage surgery under navigation guidance
Authors: Cho Hwan Seong , Oh Joo Han , Han Ilkyu , Kim Han‐Soo 
Published: March 2009

AbstractBackgroundRecently, the navigation system has been introduced to orthopedic oncology. It can apply MRI and/or CT images to intraoperative visualization. We performed navigation‐assisted limb salvage surgeries on patients with a malignant bone tumor of the metaphysis of the long bone or the iliac bone while preserving the adjacent joint.MethodsWhen preoperative chemotherapy was estimated to be effective by imaging studies and the residual remaining epiphysis was expected to be more than 1 cm long after tumor resection with 1–2 cm of surgical margin, joint‐preserving surgery was performed under navigation guidance. We carried out CT and MRI data fusion to use MR images as an intraoperative guide. A deep frozen strut allograft was placed in the defect for the restoration of anatomical continuity.ResultsResection margin measured on pathological examination was in accordance with that of the preoperative plan. The functional scores of all patients were satisfactory. There was no evidence of recurrence on the regional radiographs and CT on the chest until the last follow‐up.ConclusionNavigation‐assisted surgery can be indicated for limb salvage and it can help to preserve the adjacent joint in selected cases. J. Surg. Oncol. 2009;100:227–232. © 2009 Wiley‐Liss, Inc.
Direkte und indirekte Gefahren von Laserstrahlung (Teil II)
Authors: Foth Hans‐Jochen 
Published: March 2009

AbstractUm den erneuten Einstieg in das Thema zu erleichtern, hier zunächst eine kurze Wiederholung der Punkte, die im ersten Teil des Artikels (LTJ 5/2008) beschrieben wurden:
Polymer Brushes by Nitroxide‐Mediated Polymerization
Authors: Brinks Marion K. , Studer Armido 
Published: March 2009

AbstractThis review article describes the preparation of polymer brushes by nitroxide‐mediated radical polymerization using either the ‘grafting to’ or the ‘grafting from’ approach. The use of TEMPO as a classical initiator is intensively described. More sophisticated nitroxides are also included in the discussion. Brush formation on flat surfaces such as wafers and also on particles is reported. Finally, some applications of polymer brushes are presented.magnified image
Self‐assembly of Sulfonated Polystyrene Ionomers in Chloroform
Authors: Lezov A. V. , Polushina G. E. , Mikhailova M. E. , Rjumtsev E. I. 
Published: March 2009

AbstractLight scattering and electric birefringence were used to determine the dimensions and extent of aggregation of dilute solutions of sodium sulfonated polystyrene ionomers with sulfonation levels of 0.5, 1.35, 2.6 and 5.8 mol% in chloroform. It was found that in solutions of ionomers with sulfonation level 1.35 and more the equilibrium between single chains and aggregates consisting of two and more chains is observed. These data were analyzed using the “open” association model. It was shown that an increase in the sulfonation level of ionomers results in a decrease in the hydrodynamic radius of single chain. On the other hand, it was established that an increase in sulfonation level leads to increase in the size of aggregate consisting of two chains. More pronounced expansion of ionomer chains incorporated into aggregate was found for ionomers with high sulfonation level.
Synthesis, characterization, thermal stability, conductivity, and band gaps of substitute oligo/polyamines or polyphenol
Authors: Kaya İsmet , Aydın Aysel 
Published: March 2009

AbstractIn this study, the oxidative polycondensation reaction conditions of 3,5‐dichloroaniline (DCA), 3,4,5‐trimethoxyaniline (TMA), 3,5‐bis(trifluoromethyl)aniline (BTFMA), and 4‐{[(3,5‐dichlorophenyl)imino]methyl}phenol (DCPIMP) were studied by using NaOCl oxidant in an aqueous alkaline medium between 40 and 90°C. The structures of the synthesized monomer and polymer were confirmed by FT‐IR, Ultraviolet–visible (UV–vis), 1H‐NMR, and 13C‐NMR and elemental analysis. The characterization was made by TGA–DTA, size exclusion chromatography (SEC), and solubility tests. At the optimum reaction conditions, the yields of oligo‐3,5‐dichloroaniline (ODCA), poly‐3,4,5‐trimethoxy aniline (PTMA), oligo‐3,5‐bis(trifluoromethyl)aniline (OBTFMA), and poly‐4‐{[(3,5‐dichlorophenyl) imino]methyl} phenol (PDCPIMP) were found to be 98, 48, 80, and 83% in using NaOCl oxidant. According to the SEC analysis, the number‐average molecular weight (Mn), weight‐average molecular weight (Mw) and polydispersity index (PDI) values of ODCA, PTMA, and OBTFMA were found to be 2200, 3800 g mol−1, and 1.727; 4700, 7500 g mol−1, and 1.596; and 1690, 1950 g mol−1, and 1.154, respectively. According to TG analysis, the weight losses of ODCA, PTMA, OBTFMA, and PDCPIMP were found to be 78.55, 54.18, 99.38, and 59.70% at 1000°C, respectively. PTMA showed higher stability against thermal decomposition. Electrical conductivity of the polymers was measured, showing that the polymer is a typical semiconductor. The highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO) and electrochemical band gaps ($E'_{\rm g} $) of ODCA, PTMA, OBTFMA, and PDCPIMP were calculated from their absorption edges of cyclic voltammograms. The optical band gaps (Eg) values of all compounds were calculated from UV–vis measurements. Copyright © 2009 John Wiley & Sons, Ltd.