bluuebunny/crossref_metadata_2025_split huggingface dataset:
Solubility of argon in acetone + water mixed solvent at 288.15, 298.15 and 308.15 K
Authors: Yamamoto Hideki , Tokunaga Junji , Koike Keiji 
Published: March 2009

AbstractSolubilities of argon were determined in acetone + water mixed solvent over the full range of composition using a static method. The gas solubilities were measured at three temperatures of 288.15, 298.15 and 308.15 K. The solubility dependence on the temperature in the mixed solvent was measured and discussed, and the similarity between excess quantities of mixed solvent and those of gas solubilities was examined.The order of gas solubility of argon in acetone + water mixed solvent at the three different temperatures was 288. 15 > 298.15 > 308.15 K in the composition range of 0 ≤ x22 ≤ 0.15. However, the reverse relationship with temperature was observed in the range of composition of 0.15 < x2 ≤ 1.0. For all solubility curves, maximum and minimum values of solubility were observed at lower temperatures, but not at higher temperatures. Furthermore, the excess Ostwald coefficients on the basis of volume fraction which express the non‐ideality of gas solubility in non‐ideal solutions were defined, and they were expressed by a polynomial equation of the Redlich‐Kister (1948) type.
Wall‐to‐bed heat transfer in three‐phase fluidized beds of low density particles
Authors: Nore O. , Wild G. , Briens C. L. , Margaritis A. 
Published: March 2009

AbstractBed‐to‐wall heat transfer was measured in three‐phase fluidized beds under conditions typical of biochemical process applications. The thermal resistance of the fluidized bed, which was significant in the absence of gas, became negligible when gas was introduced. Decreasing the particle density at constant gas and liquid velocity increased the bed‐to‐wall heat transfer coefficient.Previously published heat transfer correlations were used and gave poor predictions of our data. A new correlation was developed which predicted very well all the heat transfer coefficient results in this paper.
Adsorption of sodium dodecyl sulphate on cassiterite surface
Authors: González‐Martín M. L. , Janczuk B. , Bruque J. M. , Dorado‐Calasanz C. 
Published: March 2009

AbstractMeasurements of the adsorption of sodium dodecyl sulphate (SDS) onto cassiterite were made. It was found that at SDS concentrations below 10 −3 mol/L the adsorption depended on the manner of preparation of the cassiterite and the pH of solution. However, the adsorption isotherms showed a point of inflection at l0 −3 mol/L corresponding to an occupied area per molecule of about 0.8 nm2. This value is close to the surface area covered by one dodecyl sulphate ion (DS −) as evaluated from the molecular structure of SDS. Near the critical micelle concentration (cmc), a plateau was found which corresponded to the adsorption of two statistical monolayers of DS − ions vertically oriented to the surface.
Particle velocity profiles and solid flow patterns in spouted beds
Authors: He Y.‐L. , Qin S.‐Z. , Lim C. J. , Grace J. R. 
Published: March 2009

AbstractA fibre optic probe system was used to measure the profiles of vertical particle velocities in the spout and the fountain of a half‐column and a full‐column spouted bed. In addition, a fibre optic image probe was employed to measure vertical particle velocity profiles in the annulus of the full‐column. In the spout, radial profiles of vertical particle velocities were of near Gaussian distribution. Particle velocities along the spout axis in the half‐column were 30% lower than in the full‐column under identical operating conditions. In the half column, particle velocities adjacent to the front plate were approximately 24% lower than a few millimeters away. The fountain core expanded suddenly near the bed surface and then gradually contracted with height. The model of Grace and Mathur (1978) gave good predictions of fountain heights for the full‐column. In the annulus region, there was a 28% difference between particle velocities adjacent to the column wall and those only 2 mm away. The integrated upward solids mass flow in the spout and the downward solids flow in the annulus matched well at different bed levels.
An optimal operational strategy for wood in batch drying system
Authors: Hwang Bing Joe , Wang Cheng‐Hsing , Liou Ching‐Tein 
Published: March 2009

AbstractA complete model based on the wood drying mechanism and incorporating a multi‐period operation was established for wood in batch drying systems. Both energy savings and improvement of wood quality were obtained by an optimal strategy proposed in this study. Energy saving was indicated by the numerical results to be roughly 22.5% for drying of soft wood under the conditions of a given drying time and final moisture content. The gradient of moisture content within the dried wood could be minimized for the sake of enhancing the quality of wood by applying the proposed operational model.
Methanol synthesis under periodic operation: An experimental investigation
Authors: Chanchlani K. G. , Hudgins R. R. , Silveston P. L. 
Published: March 2009

AbstractExperiments have been conducted on Cu/ZnO and Cu/ZnO/Al2O3 catalysts at 225°C and 2.86 MPa in an isothermal, differential packed bed reactor to identify promising periodic operations strategies and find cycling variables which give the largest improvement in the synthesis rate relative to steady state. Modulating the H2 and CO2 concentrations appears to be the best strategy. However, the increased rate under composition modulation was insensitive to cycle period, amplitude and split in the cycle period range from 2 to 30 min. Higher methanol yield resulted from the suppression of the reverse water gas shift reaction. Higher rates under cycling arise from structural or compositional changes to the catalyst surface.
Flow characteristics of hyperboloid stirrers
Authors: Nouri J. M. , Whitelaw J. H. 
Published: March 2009

AbstractThe flows in a fully‐baffled vessel with a diameter T = 144 mm driven by hyperboloid stirrers of diameters D = 773 and 27/3 have been visualised and characterised by local measurements of velocity and turbulence and by power number. The results were obtained for a range of rotational speeds from 6 to 40 rev/s. The visualisation showed that the larger stirrer gave rise to a radial jet and that the smaller stirrer formed a jet inclined towards the base of the vessel so that there was a tendency for the system of two vortices, one above and one below the jet, to give way to a single vortex as the clearance between the stirrer and the base of the vessel was reduced. The velocity measurements revealed bulk‐flow values an order of magnitude less than that of the maximum radial velocity in the jet, that the maximum radial velocity was 24% of the circumferential velocity of the tip of the stirrer, and that the radial velocities were proportional to the rotational speed.The flows generated by the hyperboloid stirrer were less vigorous than those of Rushton impellers of similar radius and were associated with power numbers 28 times less. The power number did not vary with rotational speed or with clearance within the measured range. The contrast with propeller and disc stirrers is less pronounced, but the hyperbolic profile is likely to find application and the present results provide a basis for choice.
Modeling of porous radiant burners with large extinction coefficients
Authors: Escobedo F. , Viljoen H. J. 
Published: March 2009

AbstractA comparative study of numerical and analytical results for a porous radiant burner (PRB) is presented. It is shown that the analytical method captures all the features of the system and can be used for quantitative applications. Two solutions are found, one is located close to the inlet of the burner and the second one is close to the outlet. The effects of the molar flow rate, the interphase heat transfer coefficient (hs) and the location of the flame in the matrix, on the radiation efficiency (RE) of the burner are studied. Local maxima in the RE vs. hs curves indicate that intermediate values of hs will be the optimum choice. Other trends are also analyzed and some recommendations are made.
Chemical absorption of mercaptan in an aerosol operated loop reactor
Authors: Kube C. H. , Blume T. , Prüss J. , Warnecke H.‐J. 
Published: March 2009

AbstractA mechanistic mathematical model for the chemical absorption of mercaptan in sodium hypochlorite solution has been derived. In order to describe the process adequately, a semi‐verified complex scheme of the involved kinetic reactions based on stopped‐flow measurements with UV‐detection has been implemented. The overall system of differential equations has been solved numerically. For some asymptotic cases, approximation formulae are given. The process has been carried out in an aerosol operated jet loop reactor which is characterized by high interfacial areas at low liquid flow rates. Fitting the model solution to the experimentally obtained conversion data enabled determination of the unknown hydrodynamic parameters. By means of a sensitivity analysis, the influences of the different parameters are discussed.
Simultaneous hydrolysis and fermentation of pulp mill primary clarifier sludge
Authors: Duff Sheldon J. B. , Moritz John W. , Andersen Kari L. 
Published: March 2009

AbstractBioconversion of sludge from the primary clarifier of a sulphite pulping operation to ethanol offers a number of advantages over conventional disposal options. The amount of material which must be disposed of is reduced while, at the same time, salable and environmentally friendly fuel‐ethanol is produced. In this study, primary clarifier sludge (PCS) was shown to be hydrolysed to produce fermentable sugars at a rate proportional to enzyme loading. Initial (1 hour) hydrolysis rates as high as 12.6 g reducing sugar/L · h were observed at an initial enzyme loading of 10 filter paper units (FPU)/g. Hydrolysis was inhibited by spent sulphite liquor (SSL), an inhibition which could be completely overcome by fermenting the SSL to remove sugars. Surfactants were found to only marginally improve the production of sugars. To reduce the deleterious effects of end product inhibition, single stage simultaneous hydrolysis and fermentation (SHF) was carried out using cellulase enzymes and Saccharomyces cerevisiae.
Molecular transport of organic esters and ketones into fluoropolymer membranes
Authors: Aminabhavi T. M. , Munnolli R. S. 
Published: March 2009

AbstractThe effect of different fluorine contents of DuPont VITON fluoropolymers and their transport characteristics in the presence of phenyl acetate, diethyl oxalate, diethyl malonate, diethyl succinate, acetone, methyl ethyl ketone and methyl iso‐butyl ketone has been investigated over the temperature interval of 25−60°C. The average values of diffusion coefficients are obtained from the Fickian relation and the molecular transport is found to follow an anomalous behavior. Kinetic rate constants and pentration velocities are also calculated. The experimental results and the calculated quantities are studied in terms of polymer‐solvent interactions.
Optimal averaging level control for the tennessee eastman problem
Authors: Ye Nan , Mcavoy Thomas J. , Kosanovich Karlene A. , Piovoso Michael J. 
Published: March 2009

AbstractThis paper focuses on an industrial test problem, the Tennessee Eastman problem. The Tennessee Eastman process is moved to three operation modes with 90/10, 50/50 and 10/90 product G/H ratios. The base control system proposed in an earlier paper can properly control the process at all the three operation modes. Optimal averaging level control is added to the base control to improve the control of product flow during random and step feed disturbances. A new implementation of the optimal feedback averaging control algorithms (McDonald et al., 1986) is presented in order to deal with random disturbances. Simulation results show that control of product flow rate is significantly improved by using the optimal feedback averaging level control at all three operation modes.
The possible negative impacts of volunteer tourism
Authors: Guttentag Daniel A. 
Published: March 2009

AbstractVolunteer tourism is an increasingly popular form of travel that is attracting growing research attention. Nevertheless, existing research has focused primarily on the benefits of volunteer tourism, and many studies have simply involved profiling volunteers or investigating their motivations. However, there are numerous possible negative impacts of volunteer tourism that deserve increased attention from both researchers and project managers: a neglect of locals' desires, a hindering of work progress and completion of unsatisfactory work, a disruption of local economies, a reinforcement of conceptualisations of the ‘other’ and rationalisations of poverty, and an instigation of cultural changes. Copyright © 2009 John Wiley & Sons, Ltd.
Analysis of Stem Cell Lineage Progression in the Neonatal Subventricular Zone Identifies EGFR+/NG2− Cells as Transit-Amplifying Precursors
Authors: Cesetti Tiziana , Obernier Kirsten , Bengtson C. Peter , Fila Tatiana , Mandl Claudia , Hölzl-Wenig Gabriele , Wörner Kerstin , Eckstein Volker , Ciccolini Francesca 
Published: March 2009

Abstract
In the adult subventricular zone (SVZ), astroglial stem cells generate transit-amplifying precursors (TAPs). Both stem cells and TAPs form clones in response to epidermal growth factor (EGF). However, in vivo, in the absence of sustained EGF receptor (EGFR) activation, TAPs divide a few times before differentiating into neuroblasts. The lack of suitable markers has hampered the analysis of stem cell lineage progression and associated functional changes in the neonatal germinal epithelium. Here we purified neuroblasts and clone-forming precursors from the neonatal SVZ using expression levels of EGFR and polysialylated neural cell adhesion molecule (PSANCAM). As in the adult SVZ, most neonatal clone-forming precursors did not express the neuroglia proteoglycan 2 (NG2) but displayed characteristics of TAPs, and only a subset exhibited antigenic characteristics of astroglial stem cells. Both precursors and neuroblasts were PSANCAM+; however, neuroblasts also expressed doublecortin and functional voltage-dependent Ca2+ channels. Neuroblasts and precursors had distinct outwardly rectifying K+ current densities and passive membrane properties, particularly in precursors contacting each other, because of the contribution of gap junction coupling. Confirming the hypothesis that most are TAPs, cell tracing in brain slices revealed that within 2 days the majority of EGFR+ cells had exited the cell cycle and differentiated into a progenitor displaying intermediate antigenic and functional properties between TAPs and neuroblasts. Thus, distinct functional and antigenic properties mark stem cell lineage progression in the neonatal SVZ.
Disclosure of potential conflicts of interest is found at the end of this article.
Dax-1 Knockdown in Mouse Embryonic Stem Cells Induces Loss of Pluripotency and Multilineage Differentiation
Authors: Khalfallah Olfa , Rouleau Matthieu , Barbry Pascal , Bardoni Barbara , Lalli Enzo 
Published: March 2009

Abstract
Dax-1 (Nr0b1) is an orphan member of the nuclear hormone receptor superfamily that has a key role in adrenogonadal development and function. Recent studies have also implicated Dax-1 in the transcriptional network controlling embryonic stem (ES) cell pluripotency. Here, we show that Dax-1 expression is affected by differentiating treatments and pharmacological activation of β-catenin–dependent transcription in mouse ES cells. Furthermore, Dax-1 knockdown induced upregulation of multilineage differentiation markers, and produced enhanced differentiation and defects in ES viability and proliferation. Through RNA interference and transcriptome analysis, we have identified genes regulated by Dax-1 in mouse ES cells at 24 and 48 hours after knockdown. Strikingly, the great majority of these genes are upregulated, showing that the prevalent function of Dax-1 is to act as a transcriptional repressor in mouse ES cells, as confirmed by experiments using the Gal4 system. Genes involved in tissue differentiation and control of proliferation are significantly enriched among Dax-1–regulated transcripts. These data show that Dax-1 is an essential element in the molecular circuit involved in the maintenance of ES cell pluripotency and have implications for the understanding of stem cell function in both physiological (adrenal gland) and clinical (Ewing tumors) settings where Dax-1 plays a pivotal role in development and pathogenesis, respectively.
Disclosure of potential conflicts of interest is found at the end of this article.
The disorderly study of ordered recruitment
Authors: Biddick Rhiannon , Young Elton T. 
Published: March 2009

AbstractActivated transcription in eukaryotes requires the aid of numerous co‐factors to overcome the physical barriers chromatin poses to activation, bridge the gap between activators and polymerase, and ensure appropriate regulation. S. cerevisiae has long been a model organism for studying the role of co‐activators in the steps leading up to gene activation. Detailed studies on the recruitment of these co‐activators have been carried out for more than a dozen promoters. Taking a step back to survey these results, however, suggests that there are few generalizations that could be used to guide future studies of uncharacterized promoters. Copyright © 2009 John Wiley & Sons, Ltd.
The effect of dacryocystorhinostomy on mucociliary function
Authors: Okuyucu Semsettin , Akoglu Ertap , Oksuz Huseyin , Gorur Hatice , Dagli Safak 
Published: March 2009

ObjectiveExternal dacryocystorhinostomy is suspected to cause mucociliary dysfunction by affecting ciliary activity and quality of the mucus. We hypothesized that patients who undergo endoscopic dacryocystorhinostomy may also experience mucociliary dysfunction. We evaluated the effects of surgery on mucociliary clearance time in patients who underwent endoscopic dacryocstorhinostomy and external dacryocstorhinostomy.Study DesignA prospective controlled study.Subjects and MethodsForty‐four patients were studied: 22 had undergone one‐sided endoscopic surgery and 22 had undergone one‐sided external surgery for nasolacrimal duct obstruction. Nonoperated sides of the both groups were remained as controls. The saccharin test was used to evaluate the mucociliary clearance time of the both sides.ResultsDacryocystorhinostomy, results in prolonged mucociliary clearance times either endoscopic or external approach is performed (P < 0.001, paired t test). There was no significant difference between the mucociliary clearance times after endoscopic and external dacryocystorhinostomy (P = 0.22, Student's t test).ConclusionDacryocystorhinostomy impairs mucociliary function independent of the type of surgery.
Balloon sinuplasty for the surgical management of immunocompromised and critically ill patients with acute rhinosinusitis
Authors: Wittkopf Maria L. , Becker Samuel S. , Duncavage James A. , Russell Paul T. 
Published: March 2009

ObjectiveThe purpose of this study was to review use of balloon sinuplasty for surgical treatment in critically ill patients with acute sinusitis.Study DesignCase series with chart review.Subjects and MethodsPatients who underwent balloon sinuplasty between October 2007 and March 2008 were identified. Medical records of the subset of patients who were immunocompromised or otherwise critically ill were analyzed.ResultsThirty‐one patients underwent balloon sinuplasty at our institution between October 2007 and March 2008. We identified five critically ill patients with sinus disease within this group. Patient ages ranged from 15 to 51 years with no sex preponderance. All patients had focal findings on a sinus CT scan. In all cases, purulent drainage was noted intraoperatively. All patients returned to baseline health meeting discharge criteria after treatment.ConclusionBalloon sinuplasty represents a potentially less invasive surgical option than standard Functional Endoscopic Sinus Surgery (FESS) and should be considered in the treatment of critically ill or immunocompromised patients.
Microatoll record for large century-scale sea-level fluctuations in the mid-Holocene
Authors: Yu Ke-Fu , Zhao Jian-Xin , Done Terry , Chen Te-Gu 
Published: March 2009

AbstractCoral microatolls have been long used as precise indicators of past sea level, but their use for precise definition of detailed sea-level fluctuations is still rare. Here we report twelve high-precision thermal ionization mass spectrometric 230Th ages for twelve rims of five mid-Holocene microatolls from an emerged reef terrace at Leizhou Peninsula, northern South China Sea. This is a tectonically stable area, enabling us to reconstruct both the timing and trajectory of local sea-level fluctuations accurately. The elevations of these microatoll rims and cores were accurately determined relative to the surface of modern living microatolls at the same site. The results indicate that the sea level during the period of 7050–6600 yr bp (years before AD 1950) was about 171 to 219 cm above the present, with at least four cycles of fluctuations. Over this 450 yr interval, sea level fluctuated by 20–40 cm on century scales.
Early human impact in the forest ecotone of southern High Asia (Hindu Kush, Himalaya)
Authors: Miehe Georg , Miehe Sabine , Schlütz Frank 
Published: March 2009

AbstractThe vegetation of the treeline ecotone of the southern declivity of arid High Asia (Hindu Kush, northern areas of Pakistan; Himalaya, northern central Nepal) is dominated by hedgehog-like open dwarf shrublands of thorny cushions. Since climatically sensitive ecotones are always also sensitive to human impact, the question arises whether the current lack of forests is a result of the Subboreal climate decline or of human impact. Due to inadequate knowledge of the pollen flora and of ecological indicator values of the plants, pollen analyses in High Asia have mainly been limited to the regional verification of globally known climatic impulses. However, the role of human impact on regional vegetation patterns has been widely neglected. We postulate that today's open dwarf shrublands replace woodlands and forests. Isolated vigorous juniper trees and successful reforestation appear to confirm our hypothesis. An abrupt decline of Pinus forests before 5700 and 5400 ka cal yr BP can be demonstrated. As the first indicator pollen of human impact appeared at both sites synchronous with the forest pollen decline, we infer human impact to be a more decisive cause for this environment change superimposing the effects of a climatic deterioration. The forests were displaced by open dwarf shrublands.