bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reactive distillation of pyridine mixtures with an organic acid. I. Determination of the reactive distillation equilibrium
Authors: Duprat Françoise , Gau Georges 
Published: March 2009

AbstractThe reactive distillation equilibrium has been experimentally determined by chromatographic analysis of the vapor phase for various mixtures of two pyridines plus an organic acid in stoichiometric deficiency in an organic solvent. Protonation of pyridines by a weak acid seems to involve ion pair formation, while protonation by a strong acid seems to result in free ion formation, and may involve a small quantity of triple molecule ions (two pyridine molecules for one acid molecule). Steric effects are not significant in such ion formation and the chemical equilibrium constant can be predicted from the pyridine pKa difference using a linear relationship. Despite the possible formation of triple molecule ions, the reactive distillation equilibrium at constant acid quantity can be reasonably well described as an ideal liquid‐vapor equilibrium combined with an ideal chemical equilibrium. However, the increase of the chemical equilibrium constant with the acid quantity should be taken into account in a more refined model.
Mecanismes de colmatage et performances comparées de quatre membranes d'alumine: Cas de l'ultrafiltration de gelatine
Authors: Freund Ph. , Rios G. M. 
Published: March 2009

AbstractDans cet article, les performances de quatre membranes tubulaires d'alumine SCT de diamètres de pores différents (0.2, 0.8, 1.4 et 2.0 μm respectivement) ont été étudiées pour différentes conditions de pression, vitesse tangentielle et concentration de fluide. L'analyse des résultats obtenus (débits de perméation au solvant pur des membranes propres ou conditionnées, débits d'ultrafiltration, taux de rétention des espèces protéiques) au moyen de modèles simples (théorie de la filtration, théorie du film) amène les auteurs à émettre des hypothèses originales quant au mode de fonctionnement particulier de chaque élément filtrant. En particulier, il est établi que les mécanismes de mise en place et le type du colmatage évoluent fortement d'une membrane à l'autre. Enfin, les auteurs concluent que, pour les conditions expéri‐mentales choisies, c'est la membrane de 0.2 μm qui en règie générate permet d'atteindre les débits d'ultrafiltration et taux de rétention maxima.
Enzymatic production of l‐alanine from malic acid with malic enzyme and alanine dehydrogenase with coenzyme regeneration
Authors: Suye Shin‐Ichiro , Kawagoe Mikio , Inuta Shusei 
Published: March 2009

AbstractAn enzyme reaction system with coenzyme regeneration was investigated for L‐alanine production. Alanine dehyrogenase L‐alanine: NAD+ oxidoreductase (EC 1.4.1.1)] from Corynebacterium flaccumfaciens AHU‐1622 was used as the catalyst for reductive amination of pyruvate to L‐alanine. NAD‐ and NADP‐linked malic enzyme [L‐malate: NAD(P)+ oxidoreductase (EC 1.1.1.39)] from Pseudomonas diminuta IFO‐13182 was used for the regeneration of NADH. Optimum conditions for L‐alanine production were determined, including L‐malic acid concentration, MgCl2 concentration and pH. Under suitable conditions, the conversion of L‐malic acid to L‐alanine reached 95% after 72 h of incubation at 30°C, yielding 106 mol/m3 of L‐alanine. The L‐alanine produced was purified in crystal form; its purity was 99.4%, based on HPLC analysis.
A priori modelling of an adiabatic spouted bed catalytic reactor
Authors: Hook Bruce D. , Littman Howard , Morgan Morris H. , Arkun Yaman 
Published: March 2009

AbstractAn a priori reactor model for an adiabatic spouted bed reactor has been developed. This model uses first‐principles mass and energy balances to predict the concentration and temperature profiles in the spout, annulus and fountain regions of the reactor. The particle circulation and voidage profiles in the spout are calculated using previously developed analytical techniques. Particle circulation patterns in the annulus are determined by a minimum path‐length analysis. The spout and fountain are shown to contribute significantly to the overall conversion in the bed. Predicted and experimental conversions at flowrates up to 1.2Ums show that extension of the fountain reaction zone and increased particle circulation with increasing inlet flow makes up for the higher average voidage in the spout and fountain. Experimental data confirm the calculated results for a stably spouting bed with CO oxidation over a Co3O4/αAl2O3 catalyst. The effects of flowrate and inlet reactant concentration are confirmed.
Role of sparger design on gas dispersion in mechanically agitated gas‐liquid contactors
Authors: Rewatkar V. B. , Joshi J. B. 
Published: March 2009

AbstractCritical impeller speeds for gas dispersion and gas recirculation were measured in 0.57, 1.0 and 1.5 m i.d. vessels, using visual observations, measurements of power consumption and liquid‐phase mixing time. A pitched blade down‐flow turbine impeller (PTD) was used. Design parameters of the PTD impeller such as diameter (0.22Tto 0.57T), blade width (0.25D to 0.4D) and blade thickness (2.8, 4.3 and 6.4 mm) were studied. The effect of sparger type and geometry on NCD has been investigated. For this purpose, pipe, ring, conical and concentric ring spargers were employed. Design details of the ring sparger such as ring diameter, number of holes and hole size were also studied in detail. The sparger location with respect to the impeller was found to be the most important parameter. Correlations have been developed for NCD and NCR.
Solubility of methane in glycols at elevated pressures
Authors: Jou F.‐Y. , Otto F. D. , Mather A. E. 
Published: March 2009

AbstractThe solubility of methane in ethylene glycol and in diethylene glycol has been determined at temperatures in the range 25 to 125 °C at pressures up to 20.4 MPa. The experimental results were correlated by the Peng‐Robinson (1976) equation of state, and interaction parameters have been obtained for these systems. Henry's constants were derived for comparison with data from the literature.
Corréation entre la stabilité colloïdale de la matière première et le degré de dispersion du noir de carbone
Authors: Chaala et A. , Benallal B. 
Published: March 2009

AbstractThe evolution of carbon black technology allows, at present, various hydrocarbon products as fillers in complex mixtures.The fillers investigated in this work are made of a blend of five products from different origins.The objective of this work is the study of the correlation between the colloidal stability of the filler and the quality of the carbon black, as well as the relation between the degree of dispersity of the carbon black and the resin tensile strength.
Polymer reaction engineering: From reaction kinetics to polymer reactor control
Authors: Penlidis A. 
Published: March 2009

AbstractPolymer reaction engineering is a relatively “young”, very broad, multidisciplinary, rapidly developing field. It is the combination of polymer science, chemistry and technology with process engineering principles. The outcome of this high degree of synergism has evolved over the last fifteen or so years towards an area that includes any or all of the following: polymerization and post‐polymerization (chemical modification) reaction kinetics; mathematical modelling and process simulation; polymer reactor design and scale‐up; sensor development and process monitoring; and polymer reactor optimization, state estimation and computer control.This article will attempt to give an overview of the results obtained in our laboratory over the last seven years from systematic studies of polymer reaction engineering and polymer production technology problems. These problems cover all aspects of polymer reaction engineering mentioned above. Going from fundamentals to practice, the basic premise of the article is that only by adopting a holistic approach can one devise effective strategies in order to achieve the final objective of more efficient polymer reactor design and control, and hence improved production systems of polymeric materials.
Fixed‐Bed adsorber dynamics in binary physisorption‐diffusion
Authors: Gomes Vincent G. , Fuller O. Maynard 
Published: March 2009

AbstractReactions carried out under conditions close to the equilibrium vapour pressure of the participating species involve physisorption on the catalyst surface. Such conditions are encountered for propene metathesis over rhenium oxide/γ‐alumina catalyst at room temperature. The sorption‐diffusion effects were tested by excluding effects due to reaction. Single‐component sorption characteristics were determined by steady‐state experiments. The model equations comprising several differential and nonlinear algebraic equations were solved by orthogonal collocation within the method of lines. The model predictions were tested against transient experiments performed in a gradientless, internal recirculation reactor.
A study of solid behavior in spouted beds using 3‐D particle tracking
Authors: Roy David , Larachi Faiçal , Legros Robert , Chaouki Jamal 
Published: March 2009

AbstractA non‐invasive γ‐ray emission system, employing eight NaI detectors, has been developed to follow the motion of a single radioactive particle in a three‐dimensional spouted bed reactor. The count‐rates measured simultaneously by the detectors are converted into tracer coordinates (x, y, z) using a pre‐established calibration model which accounts for every physical and geometrical aspects involved in the spouting facility. Typically four hundred thousands successive coordinates, obtained over 3.5 hours of particle tracking, are used for determining the average particle velocity field and other hydrodynamic quantities such as the cycle time distribution, the spout shape and the solid exchange distribution at the spout boundary, which could not be evaluated accurately using any available techniques.
Transient forced convection in the entrance region of porous concentric annuli
Authors: Al‐Nimr M. A. , Aldoss T. K. , Naji M. I. 
Published: March 2009

AbstractThe problem of transient laminar forced convection in the entrance region of a porous concentric annulus with developing thermal boundary layer is solved numerically by the finite difference technique. The hydrodynamic behaviour of the flow is assumed to be steady and fully developed, and both Darcian and non‐Darcian effects on the flow are considered.
Process for production of arachidonic acid concentrate by a strain of mortierella alpina
Authors: Li Zu‐Yi , Lu Yingyin , Yadwad V. B. , Ward O. P. 
Published: March 2009

AbstractVarious Mortierella alpina fungi were screened for their capacities to produce arachidonic acid. A strain of M. alpina was found to show the highest productivity. Arachidonic acid content of biomass and overall yield per litre of culture was highest in soya flour supplemented medium which produced dispersed mycelium. When the glucose concentration in the medium was varied from 30 to 100 g/L, biomass, lipid, arachidonic acid content of biomass and arachidonic acid yield increased with increasing glucose concentration. Several natural oils, when added to the growth medium, stimulated arachidonic acid production. After fermentation in a 20‐L fermenter under optimal culture conditions, the arachidonic acid yield was 5.3 g/L, representing 34.2% w/w of total fatty acids and 13.7% w/w of biomass. An extract containing 72.5% w/w arachidonic acid was prepared from the recovered mycelium.
Kinetic modeling of the hydrolysis of carbon disulfide catalyzed by either titania or alumina
Authors: Tong S. , Dalla Lana I. G. , Chuang K. T. 
Published: March 2009

AbstractThe reaction rates for the hydrolysis of CS2on either alumina (Kaiser 201) or titania (CRS 31) were measured at 150 kPa and from 270 to 330°C using a laboratory Berty reactor over ranges of water concentration (2–12 mol%) and CS2concentration (0.5–2 mol%). Four mechanism‐related model functions were tested in the search for the best‐fitting rate function by using non‐linear regression techniques. The results show that the Eley‐Rideal rate function best‐fitted the kinetics using either Kaiser 201 or CRS 31 with different parameters. The kinetic parameters obtained confirm that CRS 31 appears to have the higher activity of the two catalysts for CS2hydrolysis. The strong adsorption of water vapor on each of the two catalysts studied inhibits the hydrolysis rate and affords an effective reaction order close to zero for H2O, possibly by saturating the catalysis surface and reducing the fraction of catalyst surface available for CS2and COS adsorption.
Dynamical model for indoor radon concentration monitoring
Authors: Brabec Marek , Jílek Karel 
Published: March 2009

AbstractIn this paper, we will deal with interesting example of natural risk modeling – namely of indoor radon concentration, needed for proper exposure assessment and appreciation of quality of preventive measures taken. First, we will illustrate, how the traditional view based on fixed (i.e., time‐invariant) coefficient models can be misleading. Then we formulate a flexible (nonparametric) regression dynamic model offering a doable alternative. Situation is not entirely standard here, as the smoothed and weight‐giving variables are different. Nevertheless, estimation for our local regression formulation is easily doable even for rather large data via extension of standard local smoothing that we describe. We illustrate on data coming from a rare intensive measurement campaign in an occupied house with simultaneous measurements taken in different rooms. Our model has nice physical interpretation of its parts. We also illustrate how even such a simple model can produce behavior that throws some light on radon experts' discussions about natural radon concentration circadial movement phase. This is because our model acts as a linear but time‐varying filter that can change not only amplitude but also phase between different rooms of the same house, suggesting that there might not be a universal phase of (e.g., daily) radon variation. Instead, the phase might depend on how close a particular indoor location is to the radon sources. Finally, we present some ideas about how our model can be expanded in future to cover more complicated situations and settings. Copyright © 2009 John Wiley & Sons, Ltd.
Nasal tip augmentation in Asians using autogenous cartilage
Authors: Jin Hong‐Ryul , Won Tae‐Bin 
Published: March 2009

ObjectivesTo present surgical techniques and results of nasal tip augmentation in Asian noses and suggest a surgical algorithm for a successful outcome.Study DesignA case series at a tertiary hospital.Subjects and MethodsOne hundred and seven patients who had undergone nasal tip augmentation using autogenous cartilages from January 2005 to December 2006 were enrolled in the study. Medical records, graphic operation records, and standardized patient photographs were retrospectively reviewed. Initial diagnoses, techniques for tip augmentation, combined tip surgery techniques, surgical results, and complications were analyzed.ResultsInitial diagnoses included deviated nose, hump nose, saddle nose, low‐profile nose, and short nose. An external approach was used in 74 percent and intranasal approach in 26 percent. For augmentation of the tip projection, onlay grafts with or without columellar strut (59%) and septal extension grafts with or without onlay grafts (25%) were the most commonly used techniques. Ninety‐three percent of the patients were satisfied with the results. Complications included tip deviation and visible tip graft.ConclusionAugmentation of nasal tip projection in Asians can be effectively performed using autogenous cartilage. Onlay graft and septal extension graft are two important techniques for a successful outcome.
Humanitarian otologic missions: Long‐term surgical results
Authors: Horlbeck Drew , Boston Mark , Balough Ben , Sierra Ben , Saenz Guillermo , Heinichen Julio , Duckworth Laurie 
Published: March 2009

ObjectiveThe purpose of this study was to determine the efficacy of treating chronic ear disease by performing a single surgical intervention in the austere environment of a developing nation.Subjects and MethodsData were collected from retrospective chart reviews on 121 patients who underwent surgical treatment of chronic ear disease during humanitarian surgical missions in South and Central America. Surgical outcomes and clinical course were assessed at 10 to 12 months after the initial surgery.ResultsA total of 117 patients were included in the study. Follow‐up records were available for 75 patients (64%). A total of 20 surgeries were performed for dry perforations (group 1), 30 for chronically draining ears (group 2), and 25 for cholesteatomas (group 3). Surgical success was determined as 60 percent, 74 percent, and 92 percent for groups 1, 2, and 3, respectively.ConclusionsSurgical results during international otologic outreach missions to developing nations fall within the results expected in developed nations.
Airway management in pediatric epiglottitis: A national perspective
Authors: Acevedo Jason L. , Lander Lina , Choi Sukgi , Shah Rahul K. 
Published: March 2009

ObjectivesThe purpose of this study was to describe current demographics and resource utilization in the treatment of pediatric epiglottitis.Study DesignCase series from a national database.Subjects and MethodsThe Kids' Inpatient Database was systematically searched to extract patients under 19 years old admitted with a diagnosis of epiglottitis and undergoing an airway intervention.ResultsThree hundred forty‐two sampled admissions were for epiglottitis; 40 of these patients were under the age of 19 and had an airway intervention (intubation or tracheotomy). On average, patients were 4.3 years old (SD = 6.0 years). The average length of stay was 15.6 days (SD = 33.9 and range = 0–199) with average total charges of $74,931 (SD = $163,387, range = $3342‐$938,512). Multivariate analysis revealed that admission to a children's facility, admission other than via the emergency room, and nonemergent admission were associated with increased total charges. Twenty‐two states reported an admission for pediatric epiglottitis that required airway intervention.ConclusionsIn our sample, only 40 patients were identified who were under the age of 19 years and required an airway intervention for the treatment of epiglottitis. Epiglottitis is a rare, expensive, and protracted disease to treat in the postvaccine era. The unique nature of this disease has implications for training future surgeons on proper management of this potentially fatal disease.
Cost of compliance with daily recommended values of micronutrients among a cohort of Spanish university graduates: the SUN (Seguimiento Universidad de Navarra) Study
Authors: Lopez Celeste N , Martinez-Gonzalez Miguel A , Alonso Alvaro , Sanchez-Villegas Almudena , de la Fuente Carmen , Bes-Rastrollo Maira 
Published: March 2009

AbstractObjectivePrevious studies have shown that highly nutritious diets are more costly, but to date there has been no evaluation of the costs associated with failing to meet micronutrient recommendations in a Spanish population.Design, setting and subjectsWe examined whether daily food consumption costs (classified in quintiles) were associated with failing to meet at least three daily nutritional recommendations out of twenty (including fibre and nineteen micronutrients) in a cross-sectional analysis of baseline data of a cohort of 17 197 Spanish university graduates. Micronutrients and fibre intake were assessed with a validated 136-item FFQ. Average cost of food was calculated from official Spanish government data.Results and conclusionsAs participants presented higher dietary energy cost from their diet, their intake of micronutrients increased significantly. Low dietary energy cost was associated with a higher likelihood of failing to meet three or more recommendations (Pfor trend <0·001 across quintiles of dietary cost), the association being stronger among female than male participants (Pfor interaction between sex and quintile of dietary energy cost <0·001).
Connexin43 phosphorylation: structural changes and biological effects
Authors: Solan Joell L. , Lampe Paul D. 
Published: March 2009

Vertebrate gap junctions, composed of proteins from the connexin gene family, play critical roles in embryonic development, co-ordinated contraction of excitable cells, tissue homoeostasis, normal cell growth and differentiation. Phosphorylation of connexin43, the most abundant and ubiquitously expressed connexin, has been implicated in the regulation of gap junctional communication at several stages of the connexin ‘life cycle’, including hemichannel oligomerization, export of the protein to the plasma membrane, hemichannel activity, gap junction assembly, gap junction channel gating and connexin degradation. Consistent with a short (1–5 h) protein half-life, connexin43 phosphorylation is dynamic and changes in response to activation of many different kinases. The present review assesses our current understanding of the effects of phosphorylation on connexin43 structure and function that in turn regulate gap junction biology, with an emphasis on events occurring in heart and skin.
Molecular characterization of swine leucocyte antigen class I genes in outbred pig populations
Authors: Ho C.‐S. , Lunney J. K. , Franzo‐Romain M. H. , Martens G. W. , Lee Y.‐J. , Lee J.‐H. , Wysocki M. , Rowland R. R. R. , Smith D. M. 
Published: March 2009

SummaryThe highly polymorphicswine leucocyte antigen(SLA) genes are one of the most important determinants in swine immune responses to infectious diseases, vaccines, and in transplantation success. Study of SLA influence requires accurate and effective typing methods. We developed a simple and rapid method to type alleles at the three classical SLA class I loci (SLA‐1,SLA‐3andSLA‐2) using the PCR‐sequence‐specific primer (PCR‐SSP) strategy. This typing system relies on 47 discriminatory PCR primer pairs designed to amplify the SLA class I alleles by groups that have similar sequence motifs. We applied this low‐resolution group‐specific typing method to characterize the SLA class I alleles present in three outbred pig populations (n = 202). Alleles from 24 class I allele groups corresponding to 56 class I genotypes were detected. We also identified 23 low‐resolution SLA class I haplotypes in these pigs and found haplotypes Lr‐1.0 (SLA‐1*01XX‐SLA‐3*01XX‐SLA‐2*01XX) and Lr‐4.0 (SLA‐1*04XX‐SLA‐3*04XX‐SLA‐2*04XX) in all three pig populations with a high prevalence. Over 80% of the pigs examined (n = 162) were found to bear at least one of these haplotypes, resulting in a combined haplotype frequency of nearly 50%. This PCR‐SSP‐based typing system demonstrates a reliable and unambiguous detection of SLA class I alleles, and can be used to effectively investigate the SLA diversity in outbred pig populations. It will help to identify the role of SLA antigens in disease‐resistant pigs and may facilitate the development of effective vaccines.