bluuebunny/crossref_metadata_2025_split huggingface dataset:
Estimation of surface diffusion coefficient in liquid phase adsorption
Authors: Miyabe Kanji , Takeuchi Shigeya 
Published: March 2009

AbstractAn estimation procedure of surface diffusion coefficient, Ds, in liquid phase adsorption was proposed. The procedure is based on a restricted diffusion model, in which Ds is correlated with molecular diffusivity by considering a restriction energy due to an adsorptive interaction between adsorbates and adsorbents. In some adsorption systems, Ds of different adsorbates could be calculated with an error less than about 50% from only one datum of each adsorption equilibrium constant. Irrespective of temperature, the procedure, can be applied for the estimation of Ds even in a wide range of Ds of about 4 orders of magnitude.
Transfert de matière et chute de pression lors d'un écoulement tourbillonnaire annulaire non‐entretenu induit par une entrée tangentielle
Authors: Lefébvre Géraldine , Neto Severino R. Farias , Aouabed Hacène , Legentilhomme Patrick , Legrand Jack 
Published: March 2009

AbstractCe travail est consacré à une étude expérimentale du transfert de matière global et des chutes de pression lors d'un écoulement annulaire tourbillonnaire non‐entretenu produit par une entrée tangentielle du fluide. Les mesures de transfert de matière global, réalisées à l'aide d'une méthode électrochimique, ont montré que le transfert de masse sur le cylindre externe de la cellule annulaire est nettement plus élevé que celui relevé sur le cylindre intérieur qui demeure cependant très supérieur à celui obtenu en présence d'un écoulement axial pleinement développé dans un espace annulaire cylindrique. Ce gain, en terme de transfert de masse, s'accompagne d'une augmentation des pertes de charge, donc de l'énergie requise pour la mise en mouvement du fluide, dont la majeure partie est directement imputable à la singularité constituée par l'entrée tangentielle. Cependant, une corrélation énergétique du transfert de matière global sur les deux cylindres de l'espace annulaire montre que l'écoulement tourbillonnaire non‐entretenu généré par une conduite tangentielle permet d'accroœtre substantiellement le transfert de masse, pour une dépense énergétique égale, par rapport à une hydrodynamique axiale pleinement développée.
A mathematical model for drum drying of black liquor slurry using superheated steam impinging jets
Authors: Shiravi Amir H. , Mujumdar Arun S. , Kubes George J. 
Published: March 2009

AbstractA mathematical model is developed and tested for drum drying of an aqueous slurry subjected to impinging jets of superheated steam. The heat and mass transfer within the slurry film was modeled as a one dimensional, pseudo unsteady diffusion problem while the external convective heat transfer rate was obtained by solving the steady full conservation equations of mass, momentum and energy numerically in two and three dimensions. A modified low Reynolds number version of the k‐ϵ turbulence model was selected after a careful evaluation of the predictive performance of various k‐ϵ models for impingement flow and heat transfer. The computed heat transfer one‐dimensional diffusion model for the slurry film. Agreement between experimental data obtained using a black liquor slurry and results of the model was found to be satisfactory.
Parameter sensitivity of kinetics‐based hydrometallurgical reactor models
Authors: Baldwin Susan A. , Demopoulos George P. 
Published: March 2009

AbstractIn this paper, we have studied the parameter sensitivity of two hydrometallurgical models: REACTSIM (for gold pressure oxidation) and ZINCSIM (for zinc pressure leaching). The parameters investigated include: the oxygen mass transfer coefficient, kLa, the activation energy for pyrite oxidation, Ea, pyrite and marmatite dissolution stoichiometry, the constant kinetic parameter for ferrous to ferric oxidation and the apparent equilibrium constant for ferric precipitation, KE. Model predictions were found to be more sensitive to the kinetic parameters under certain conditions than others. For ferrous to ferric oxidation kinetics, a dramatic model sensitivity was found to the constant kinetic parameter with an apparent discontinuity at values close to those found in bench scale experiments. The usefulness of simulation programs was demonstrated when non‐intuitive results were obtained showing ZINCSIM sensitivity to sulphate production to be opposite from what was expected. In the case of KE, solution chemistry was not as sensitive as the heat balance, which was affected significantly.
A simple adaptive control strategy for temperature trajectory tracking in batch processes
Authors: Chen Chyi‐Tsong , Peng Shih‐Tien 
Published: March 2009

AbstractIn this paper, a simple adaptive control strategy is suggested for temperature tracking control of batch processes. A nonlinear controller, which is in structure very simple and consists of a single parameter, is proposed. To enable this controller to control a batch process adaptively, a simple parameter tuning algorithm is derived based on the Lyapunov stability theorem. The proposed adaptive control scheme is directly operational, which does not depend on process model and the only a priori process information required is the system response direction. To demonstrate the effectiveness and applicability of the proposed scheme, illustrative examples are provided. Extensive simulation results reveal that the proposed adaptive control strategy appears to be a simple and effective approach to batch process control, which provides robust control despite the wide range of operating conditions and nonlinear dynamics of the system.
The CO‐catalyzed conversion of H2S to H2 + sulfur part 2. The thermal decomposition of COS
Authors: Faraji Farhad , Safarik Imre , Strausz Otto P. , Yildirim Erdal , Torres Manuel E. 
Published: March 2009

AbstractThe pyrolysis of COS has been studied over the temperature range 300 to 750°C using a variety of catalysts. The observed product distribution confirmed that two parallel reaction paths: 2 COS → 2 CO S2 (2) and 2 COS → CO2 + CS2 (4) are involved in the decomposition. The decomposition yield increased with rising temperature, accompanied with a shift in selectivity. At temperatures lower than ∼700°C the disproportionation reaction 4 was predominant, whereas at temperatures higher than 700°C, reaction 2 was favoured. In the high‐temperature region (700 to 750°C) it was possible to achieve full suppression of reaction 4 with added CS2. The pyrolysis of COS was also studied in a reactor packed with quartz chips without catalysts at high temperatures. Between 800 and 900°C, up to 99% conversion (with respect to the thermodynamic limit) could be achieved, with the almost complete absence of the disproportionation reaction 4. The results point to the commercial potential in the two‐step reaction sequence:

for the economic conversion of hydrogen sulfide to hydrogen and sulfur.
Turbulent dispersion coefficients in cyclone flow: An empirical approach
Authors: Salcedo Romualdo L. , Coelho Manuel A. 
Published: March 2009

AbstractAmong the various theories available to predict cyclone collection efficiency, the finite diffusivity theory of Mothes and Loffler (1988) has been shown to give the best fit of the observed grade‐efficiency curves. However, lack of knowledge on the dependence of the particles' turbulent dispersion coefficient with cyclone geometry, operating conditions and particle size has so far hindered the application of this theory for predictive purposes and for improved cyclone design. In this work, this theory is applied for predictive purposes, through the use of an empirical relation for the particles turbulent dispersion coefficient. The proposed relation is based on an analogy with turbulent dispersion in packed beds, and correlates the particle radial Peclet and Reynolds numbers. Laboratory‐scale reverse‐flow cyclones of previously unpublished geometries were built to test the applicability of the proposed relation. The Mothes and Loffler (1988) theory, when coupled with the proposed estimates of turbulent dispersion coefficients, is a powerful tool for predicting cyclone collection efficiency, short of using computational fluid dynamics tools.
Stability of gas‐inducing type impellers
Authors: Patil Swapnil S. , Josh Jyeshtharaj B. 
Published: March 2009

AbstractThe aim of this study is to understand the reasons for instability in the operation of a gas inducing impeller and to suggest the ways to eliminate the instability. Experiments were performed in a 1 m diameter vessel. The impeller clearance from the tank bottom was 0.52 m. The effects of impeller diameter, impeller blade width, blade thickness, impeller blade angle, shape of the impeller blade, impeller position with respect to the stator, impeller submergence and stator geometry on the instability were investigated. Phenomenological description has been provided for the occurrence of instability. An optimum design of a stator–impeller combination has been proposed for gas dispersion and stable operation.
Model‐based scale‐up strategy for mycelial fermentation processes
Authors: Yang He , Allen D. Grant 
Published: March 2009

AbstractWith the aid of a mathematical model describing the interrelationships between mycelial morphology, mycelial growth and product formation, rheology, mass transfer, and environmental conditions, a new scale‐up strategy has been developed, simulating the bioreactor performance at different agitation speeds. The simulations have shown that there is an optimum agitation speed, yielding maximum product formation that is different from the conventional scale‐up results based on constant Pg/VT, kL a and NI DI. It has also been shown in the simulations that the product formation scaled up by means of conventional methods is considerably lower than the simulated maximum or is close to the maximum but requiring a higher energy consumption. This indicates that model‐based scale‐up could be a more accurate and efficient method for scaling up complex systems such as mycelial fermentation processes.
Cell synchrony and periodic behaviour in yeast populations
Authors: Sheppard John D. , Dawson Peter S. S. 
Published: March 2009

AbstractThe underlying basis for the behaviour of a population of cells is the cell growth and division cycles of the individual cells. Under certain special circumstances, oscillations in cell cultures can be observed that are a reflection of metabolic oscillations, such as in glycolysis, or cell cycle oscillations from a partially synchronized population. These oscillations can sometimes occur spontaneously, as in the chemostat culture of Saccharomyces cerevisiae at low dilution rates, or can be induced using chemical blockers or entrainment by a periodic nutrient environment. Continuous methods for inducing a synchronized culture include the pulsed chemostat, continuous phasing and self‐cycling fermentation. Results obtained by studying both spontaneously oscillating cultures and synchronized cultures have provided insight into the mechanisms responsible for the progress and control of the cell cycle as well as the intimate relationship that exists between the cellular dynamics and the dynamics of the environment.
Surfactant effects on gas absorption in a coke‐oven gas treatment process
Authors: Shen Jui‐Fu , Yang Yu‐Min , Maa Jer‐Ru 
Published: March 2009

AbstractThe effect of organic impurities in industrial stripped coal water (SCW) on the absorption of CO2 was measured experimentally. Removal of these impurities via activated carbon showed a marked improvement in interphase mass transfer of a vertical wetted‐wall column absorber. However, this benefit was not found in a stirred‐cell absorber, in which a different flow pattern from that in wetted‐wall column absorber is expected. An ad hoc systematic study on the effects of three deliberately added surfactants on gas absorption by pure water in three different absorbers with different flow patterns was thereafter conducted. The experimental results reveal that absorption deterioration also prevails only in a vertical, wetted‐wall column absorber and the reduction in liquid phase mass transfer by the addition of surfactant can be satisfactorily correlated with surface pressure of solutions. This indicates that the effect of the industrial impurities in SCW on gas absorption may successfully be simulated under the same flow pattern by a surfactant solution with the same surface pressure. A possible modification of the existing coke‐oven gas (COG) treatment process for the benefit of absorption enhancement was finally proposed.
Model‐based multivariable control of the drying of a thin sheet of fibres in a continuous infrared dryer
Authors: Dhib Rhamdane , Thérien Normand , Broadbent Arthur D. 
Published: March 2009

AbstractWe developed an Internal Model Control (IMC) algorithm for drying a thin textile fabric, continuously passing through an electric infrared dryer, based on a reduced linear model of the drying dynamics. This model relates the controlled variables, the humidity and temperature of the web at the dryer outlet, to the manipulated variables, the electrical power supplied to the sources and the web speed through the dryer, and also to changes in the initial humidity of the web at the dryer inlet. The control algorithm was first tested by simulation using the model in regulation mode, and in set‐point tracking mode, to vary the manipulated variables so as to maintain the controlled variables at their respective set‐points when the inlet web temperature and humidity were changed. The performance under simulated operational conditions was compared to that of a conventional feedback proportional‐integral (PI) controller coupled with a feedforward control. The IMC controller was then tested directly in regulation mode using a pilot scale infrared dryer, acting simultaneously on the manipulated variables, the emitter power and the web speed, to control the fabric temperature and humidity at the dryer outlet. The experimental results were compared with those from the above feedback‐feedforward controller, on the pilot scale dryer. The results have indicated that the closed‐loop stability of the process is assured simply by choosing a stable IMC controller. Also, such a controller does not require the design of specific compensators for the strong interactions between variables of the drying process.
Effet d'un agitateur mécanique sur l'hydrodynamique et le transfert de matière gaz—liquide en réacteur gazosiphon
Authors: Bang Woong , Duquenne Anne‐Marie , Delmas Henri , Bascoul Aimé 
Published: March 2009

AbstractCette étude expérimentale décrit l'effet d'un agitateur sur l'hydrodynamique et le transfert de matière à l'intérieur d'un contacteur airlift à boucle interne. La contribution des deux éléments moteurs (gaz et agitateur) est identifiée. Suivant les conditions de fonctionnement, ou bien ces deux effets s'ajoutent et favorisent la circulation du liquide ou bien ces effets sont opposés, la vitesse du liquide est alors réduite. Par contre, en ce qui concerne le transfert gaz—liquide, l'utilisation de l'agitateur est bénéfique puisque, pour certaines conditions opératoires, le coefficient de transfert est multiplié par 4 par rapport à celui obtenu sans agitation. L'analyse des diverses contributions énergétiques dans l'appareil montre que la présence de l'agitateur est justifiée uniquement dans les cas où le débit de gaz doit rester faible.
A Comparison of Echocardiographic Findings in Young Adults With Cardiomyopathy: With and Without a History of Methamphetamine Abuse
Authors: Ito Hiroki , Yeo Khung‐Keong , Wijetunga Mevan , Seto Todd B. , Tay Kevin , Schatz Irwin J. 
Published: March 2009

AbstractBackgroundMethamphetamine is currently the most widespread illegal stimulant abused in the United States. No previous reports comparing echocardiographic findings of cardiomyopathy with and without a history of methamphetamine abuse are available.MethodsWe performed a single institution retrospective review of medical records and analyses of echocardiographic findings in patients ≤ 45 years of age hospitalized between 2001 and 2004 who were discharged with a diagnosis of cardiomyopathy or heart failure. After exclusion of patients with coronary artery disease or severe cardiac valvular disease, the remaining patients were divided into 2 groups based on their abuse or non abuse of methamphetamine, as determined by the documented history in the medical records or urine toxicology testing.ResultsAmong a total of 59 patients, 28 (47%) had a history of methamphetamine abuse or positive urine toxicology. Both methamphetamine abusers and non‐abusers were predominately male (64.3% vs 64.5%, P = .99), and had a high prevalence of obesity (55.6% vs 73.3%, P = .16). Bivariate analysis revealed significant differences between the methamphetamine abusers and non‐abusers in left atrium volume (119.7 ± 55.4 ml vs 85.8 ± 33.5 ml, P = .008), left ventricular end‐diastolic volume (201.9 ± 71.4 ml vs 156.6 ± 63.1 ml, P = .01), left ventricular end‐systolic volume (136.0 ± 53.7 ml vs 92.3 ± 55.8 ml, P = .004), right ventricular dimension (26.3 ± 6.0 mm vs 21.3 ± 6.0 mm, P = .007), and quantified left ventricular ejection fraction (32.9% ± 11.3% vs 44.6% ± 17.8%, P = .004).ConclusionsWe found a high prevalence of methamphetamine abuse in our study population. Methamphetamine abusers had echocardiographic findings of more severe dilated cardiomyopathy compared with non‐abusers. Copyright © 2009 Wiley Periodicals, Inc.
A novel mechanism of sperm motility in a viscous environment: Corkscrew‐shaped spermatozoa cruise by spinning
Authors: Muto Kohei , Kubota Hiroshi Y. 
Published: March 2009

AbstractFertilization of the green tree frog, Rhacophorus arboreus, occurs in the viscous environment of a foam nest, which is laid on vegetation. Their spermatozoa have a characteristic corkscrew‐shaped head and a thick tail that extends perpendicularly to its longitudinal axis. However, it is unclear how these corkscrew‐shaped spermatozoa move in this highly viscous environment. Here, we found that the spinning of the corkscrew‐shaped head, caused by winding and unwinding of the tail, enables the spermatozoa to move through the highly viscous environment of a foam nest, like a corkscrew rotating into a cork. We suggested that dislocations observed in the matrix of satellite microtubules surrounding two axonemes, reflected the planes of sliding of the axonemes, and dyneins on doublets two and six of each axoneme were active during winding and unwinding, respectively. These results provide a novel mechanism for sperm movement that is adapted specifically to a viscous fertilization environment. Cell Motil. Cytoskeleton 2009. © 2009 Wiley‐Liss, Inc.
Noble Reactions for the Actinides: Safe Gold‐Based Access to Organouranium and Azido Complexes (Eur. J. Inorg. Chem. 11/2009)
Authors: Thomson Robert K. , Graves Christopher R. , Scott Brian L. , Kiplinger Jaqueline L. 
Published: March 2009

AbstractThe cover picture shows a novel and safe gold‐based oxidative functionalization protocol that allows access to an assortment of uranium complexes bearing azide and carbon functional groups. Alkyl, alkynyl, and azide complexes are accessed in a single step from commercially available or easily prepared gold complexes. This methodology works for UIII → UIV and UIV → UV oxidations. A new, high‐yielding synthetic preparation of (Ph3P)AuN3 is also presented. These reactions proceed rapidly in high yields and represent a new class of reactions for gold. This work demonstrates that gold chemistry is not just unique for organic transformations but holds great promise for similarly advancing organometallic chemistry. Details are discussed in the Short Communication by J. L. Kiplinger et al. on p. 1451 ff. We thank Mr. Jim Cruz for designing the cover picture.
Altered functional properties of satellite glial cells in compressed spinal ganglia
Authors: Zhang Haijun , Mei Xiaofeng , Zhang Pu , Ma Chao , White Fletcher A. , Donnelly David F. , Lamotte Robert H. 
Published: March 2009

AbstractThe cell bodies of sensory neurons in the dorsal root ganglion (DRG) are enveloped by satellite glial cells (SGCs). In an animal model of intervertebral foraminal stenosis and low‐back pain, a chronic compression of the DRG (CCD) increases the excitability of neuronal cell bodies in the compressed ganglion. The morphological and electrophysiological properties of SGCs were investigated in both CCD and uninjured, control lumbar DRGs. SGCs responded within 12 h of the onset of CCD as indicated by an increased expression of glial fibrillary acidic protein (GFAP) in the compressed DRG but to lesser extent in neighboring or contralateral DRGs. Within 1 week, coupling through gap junctions between SGCs was significantly enhanced in the compressed ganglion. Under whole‐cell patch clamp recordings, inward and outward potassium currents, but not sodium currents, were detected in individual SGCs. SGCs enveloping differently sized neurons had similar electrophysiological properties. SGCs in the compressed vs. control DRG exhibited significantly reduced inwardly rectifying potassium currents (Kir), increased input resistances and positively shifted resting membrane potentials. The reduction in Kir was greater for nociceptive medium‐sized neurons compared to non‐nociceptive neurons. Kir currents of SGCs around spontaneously active neurons were significantly reduced 1 day after compression but recovered by 7 days. These data demonstrate rapid alterations in glial membrane currents and GFAP expression in close temporal association with the development of neuronal hyperexcitability in the CCD model of neuropathic pain. However, these alterations are not fully sustained and suggest other mechanisms for the maintenance of the hyperexcitable state. © 2009 Wiley‐Liss, Inc.
Dopamine neuron precursors within the developing human mesencephalon show radial glial characteristics
Authors: Hebsgaard Josephine B. , Nelander Jenny , Sabelström Hanna , Jönsson Marie E. , Stott Simon , Parmar Malin 
Published: March 2009

AbstractSpecification and differentiation of neural precursors into dopaminergic neurons within the ventral mesencephalon has been subject to much attention due to the implication of dopaminergic neurons in Parkinson's disease and the perspective of generating sources of therapeutically active cells to be used for cell replacement therapy for the disease. However, despite intensive research efforts, little is known about the characteristics of the dopamine neuron progenitors in human. We show that the dopamine neuron determinant LMX1a is expressed in the diencephalic and mesencephalic dopaminergic neuron domains during human development. Within the mesencephalon, LMX1a is expressed in the dopaminergic neurons and their progenitors located in the ventricular zone of the floor plate region. Furthermore, the neural progenitors in the developing human ventral mesencephalon have a radial morphology and express the radial glial markers Vimentin and BLBP. These radial glia are mitotic and act as precursors for the dopaminergic neurons. Finally, we show that progenitors isolated from the human ventral mesencephalon maintain their radial glial characteristics and neurogenic capacity after expansion in vitro, making them a promising future source of cells to be used in cell replacement therapy for Parkinson's disease. © 2009 Wiley‐Liss, Inc.