bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Signal Transducer and Activator of Transcription-1 Signaling on Thyroid Morphology and Function
Authors: Kimura Hiroaki J. , Rocchi Roberto , Landek-Salgado Melissa A. , Suzuki Koichi , Chen Cindy Y. , Kimura Miho , Rose Noel R. , Caturegli Patrizio
Published: March 2009

Interferon (IFN)-γ has been involved in the pathogenesis of Hashimoto thyroiditis. It is a cytokine released by infiltrating mononuclear cells that mediates its actions mainly through signal transducer and activator of transcription-1 (STAT1) but also through other transcription factors. To dissect the effect of IFNγ on thyroid morphology and function, we crossed transgenic mice that express IFNγ specifically in the thyroid gland to mice deficient in STAT1. Lack of STAT1 ameliorated the abnormal thyroid morphology and the primary hypothyroidism typical of IFNγ transgenic mice but not the suppressed iodine accumulation. Interestingly, lack of STAT1 alone decreased iodine accumulation, seemingly through expression of TGFβ. These results indicate that STAT1 is required to mediate some but not all of the phenotypic changes induced by IFNγ and that it also regulates iodine accumulation via TGFβ signaling.
Imagery rescripting for psychological disorder following cancer: A case study
Authors: Whitaker Katriina L. , Brewin Chris R. , Watson Maggie
Published: March 2009

Objectives

Intrusive memories have been identified in cancer patients and associated with psychological distress and maladaptive adjustment. Imagery rescripting is a psychological therapy that has proved successful for reducing the impact and distress associated with intrusive memories in various populations (e.g. depression). This paper describes the first application of this technique for a cancer patient reporting intrusive memories.

Design

A single‐case design was used to assess the stand‐alone therapy.

Results

Imagery rescripting was associated with significant reductions in the adverse impact of intrusive memories and psychological distress and these effects remained at 3‐ and 6‐month follow‐up.

Conclusions

Imagery rescripting shows promise for utility in medical patients experiencing intrusive memories.
Comparison of Plate Counts, Petrifilm, Dipslides, and Adenosine Triphosphate Bioluminescence for Monitoring Bacteria in Cooling‐Tower Waters
Authors: Mueller Sherry A. , Anderson James E. , Kim Byung R. , Ball James C.
Published: March 2009

Effective bacterial control in cooling‐tower systems requires accurate and timely methods to count bacteria. Plate‐count methods are difficult to implement on‐site, because they are time‐ and labor‐intensive and require sterile techniques. Several field‐applicable methods (dipslides, Petrifilm, and adenosine triphosphate [ATP] bioluminescence) were compared with the plate count for two sample matrices—phosphate‐buffered saline solution containing a pure culture of Pseudomonas fluorescens and cooling‐tower water containing an undefined mixed bacterial culture.  For the pure culture, (1) counts determined on nutrient agar and plate‐count agar (PCA) media and expressed as colony‐forming units (CFU) per milliliter were equivalent to those on R2A medium (p = 1.0 and p = 1.0, respectively); (2) Petrifilm counts were not significantly different from R2A plate counts (p = 0.99); (3) the dipslide counts were up to 2 log units higher than R2A plate counts, but this discrepancy was not statistically significant (p = 0.06); and (4) a discernable correlation (r 2 = 0.67) existed between ATP readings and plate counts.  For cooling‐tower water samples (n = 62), (1) bacterial counts using R2A medium were higher (but not significant; p = 0.63) than nutrient agar and significantly higher than tryptone‐glucose yeast extract (TGE; p = 0.03) and PCA (p < 0.001); (2) Petrifilm counts were significantly lower than nutrient agar or R2A (p = 0.02 and p < 0.001, respectively), but not statistically different from TGE, PCA, and dipslides (p = 0.55, p = 0.69, and p = 0.91, respectively); (3) the dipslide method yielded bacteria counts 1 to 3 log units lower than nutrient agar and R2A (p < 0.001), but was not significantly different from Petrifilm (p = 0.91), PCA (p = 1.00) or TGE (p = 0.07); (4) the differences between dipslides and the other methods became greater with a 6‐day incubation time; and (5) the correlation between ATP readings and plate counts varied from system to system, was poor (r 2 values ranged from <0.01 to 0.47), and the ATP method was not sufficiently sensitive to measure counts below approximately 10 4 CFU/mL.
Membrane Bioreactor Treatment of a Simulated Metalworking Fluid Wastewater Containing Ethylenediaminetetraacetic Acid and Dicyclohexylamine
Authors: Anderson James E. , Lofton Tiffany V. , Kim Byung R. , Mueller Sherry A.
Published: March 2009

Membrane bioreactors (MBRs) have been installed at automotive plants to treat metalworking fluid (MWF) wastewaters, which are known to contain toxic and/or recalcitrant organic compounds. A laboratory study was conducted to evaluate treatment of a simulated wastewater prepared from a semisynthetic MWF, which contains two such compounds, dicyclohexylamine (DCHA) and ethylenediaminetetraacetic acid (EDTA). Primary findings were as follows:

During stable operating periods, almost all chemical oxygen demand (COD), total Kjeldahl nitrogen (TKN), and EDTA were removed (by >96%). During somewhat unstable periods, COD removal was still extremely robust, but removal of EDTA and TKN were sensitive to prolonged episodes of low dissolved oxygen.

Nitrogen mass balance suggested 30 to 40% TKN removal by assimilation and 60 to 70% by nitrification (including up to 34% TKN removal via subsequent denitrification).

Dicyclohexylamine appeared to be readily biodegraded. Maximum DCHA and EDTA degradation rates between pH 7 and 8 were found.

An Arthrobacter sp. capable of growth on DCHA as the sole source of carbon and energy was isolated.
Model of a user friendly system for library cataloguing
Authors: Belic Katarina , Surla Dusan
Published: March 2009

Aim of the research is to model the system for cataloguing in the UNIMARC format which does not require specific knowledge of cataloguing formats. The Unified Modeling Language (UML 2.0) is used for the specification of both the information requirements and the architecture model of system for cataloguing. The research finding is a model of system for cataloguing in UNIMARC format by which authors themselves can process their bibliographic entries without knowing UNIMARC format. Bibliographic records formed in this way can be further processed according to adopted standards by librarians. Limitation of research results lies in the additional modeling of graphic user interface for the purpose of changing input data set of library documents. This limitation can be surpassed by specifying the input data set which would be used for automatic generation of appropriate user interface. The specification could be realized by means of XML Schema language. Practical usage of the research findings is the basic for the implementation of a Web application intended for the creation of electronic catalogues and bibliographies of researchers and scientific institutions. Integration of the catalogue into BISIS makes it publicly available through a standard user interface for searching bibliographic records on the Internet. In addition that application could be integrated into various librarian software systems. The contribution of this work is in the model architecture of the system for cataloguing in the UNIMARC format. User interface (described by use case diagrams) is connected with object model of UNIMARC format. According to that, any change or addition of new input data set of library documents requires only the change of use case diagrams which describe user interface while the rest of the model remains the same.
Hemosiderin laden macrophages and hemosiderin within follicular cells distinguish benign follicular lesions from follicular neoplasms
Authors: Jaffar Reema , Mohanty Sambit K. , Khan Ashraf , Fischer Andrew H.
Published: March 2009

Background:

Published criteria to distinguish benign colloid nodules from follicular neoplasms emphasize only three interdependent features: size of follicles, amount of colloid, and cellularity. There is a need for the validation of other independent criteria.

Methods:

This study quantified the significance of cystic change, defined as presence of macrophages, and the presence of hemosiderin in either the macrophages or follicular cells. The cohort consisted of 165 patients with fine needle aspiration (FNA) and histologic follow-up of either goiter (101), follicular adenoma (47), or follicular carcinoma (17). Papillary thyroid carcinomas and Hürthle cell neoplasms were excluded from the cohort, because these categories are known to show cystic change and hemosiderin. FNAs were reviewed blindly with the most cellular slide scored for the presence of macrophages and/or hemosiderin.

Results:

Hemosiderin within macrophages were seen in 67% (68 of 101) of the goiters and only 6% (four of 64) of follicular neoplasms (P<.0001). All four follicular neoplasms with hemosiderin in macrophages were adenomas. Three of these four had equivocal features of a benign colloid nodule histologically. None of the 17 follicular carcinomas had hemosiderin in macrophages (P<.12). Macrophages without hemosiderin also strongly distinguished goiters from neoplasms (83% vs 17%) but appears less useful as a criterion since macrophages were present within 3 of 17 follicular carcinomas. Hemosiderin within follicular epithelial cells was present in 18% (18 of 101) of goiters, whereas none of the 64 follicular neoplasms had intraepithelial hemosiderin (P<.0003).

Conclusions:

If papillary thyroid carcinoma and Hürthle cell neoplasm are ruled out, our findings indicate that the presence of hemosiderin virtually excludes a clinically significant follicular neoplasm.
CO oxidation on Pt supported catalysts. Kinetics and multiple steady states
Authors: Herskowitz M. , Kenney C. N.
Published: March 2009

The conversion of carbon monoxide to carbon dioxide was measured in a recyle reactor automatically controlled by a computer. Two Pt/SiO2catalysts of different dispersion were employed. Isothermal experiments (in which the carbon monoxide inlet concentration was varied) and temperature‐programmed experiments (in which the temperature was varied) yielded multiple steady states and complete hystereses.

The rate data were controlled well by three LHHW kinetic models. However only two of them predicted well the transitions from low to high conversion.
The mechanics of spout‐fluid beds at the minimum spout‐fluid flowrate
Authors: Hadžisdmajlović Dž. E. , Grbavčić Ž. B. , Vuković D. V. , Littman H.
Published: March 2009

Equations for predicting the minimum fluid flowrate in spout‐fluid beds of coarse spherical particles are developed and experimentally verified. Correlations for the spout diameter and maximum spoutable height are also given. The annular pressure drop equations developed in previous work are experimentally verified.
Experimental study of the thermal granulation process in a spouted bed
Authors: Dolidovich A. F. , Efremtsev V. S.
Published: March 2009

Experimental study is made of the granulation of fine dispersed materials in spouted beds. According to the first method, the granulation is carried out by blowing the gas‐dust flow through the bed of coarse particles, whose surface is melted by a high‐temperature fluidizing gas. According to the second method, the granulation occurs in the spouted bed of fine particles, a part of which has a melting temperature lower than the fluidizing gas. The effect of spouted bed parameters on granulation kinetics is studied. Correlations are obtained for calculation of a mean final diameter of granulated particles. A granule size distribution is shown to be close to the normal one.
Gravity settling in liquid/liquid dispersions
Authors: Kumar Arun , Hartland Stanley
Published: March 2009

An empirical expression for the prediction of dispersed phase hold‐up and slip velocity in droplet dispersions settling under gravity is presented. Analysis of 998 published experimental results for 29 liquid/liquid systems from 14 different data sources shows that the slip velocity of the drop swarm is given in terms of drop diameter and physical properties of the system by:

Good agreement between experimental and predicted values of slip velocity is obtained over a wide range of hold‐up (0.01 to 0.76) and Reynolds number (0.16 to 3169).
A study of the separation efficiency in horizontal thermal diffusion columns with external refluxes
Authors: Tsai Shaw‐Wei , Yeh Ho‐Ming
Published: March 2009

The separation theory of horizontal thermal diffusion columns with external refluxes, which was developed by Halle and Jury, has been derived by use of an orthogonal expansion technique. Considerable improvement is obtained when the refluxes and feed position are carefully chosen. The present formulation can be extended to other conjugated Graetz problems in continuous‐contact countercurrent separation processes with refluxes at both ends.
Generalized correlations for the aqueous liquefaction of lignocellulosics
Authors: Heitz M. , Carrasco F. , Rubio M. , Chauvette G. , Chornet E. , Jaulin L. , Overend R. P.
Published: March 2009

This paper shows that liquefaction (i.e. solubilization) of lignocellulosics in aqueous phase and in the absence of catalysts results in two general correlations. The extents of solubilization of both holocellulose and lignin are linearly related to overall conversion within the temperature range 150–270°C and up to conversions of 83%.
Catalytic wood liquefaction using a hydrogen donor solvent
Authors: Araya Paulo E. , Droguett Sergio E. , Neuburg Heinz J. , Badilla‐Ohlbaum Ricardo
Published: March 2009

Direct wood liquefaction of pine sawdust (Pinus radiata) in a hydrogen donor solvent (tetralin), was studied in a 0.5 L autoclave using Co‐Mo/γ‐Al2O3 and Pt/γ‐Al2O3 supported catalysts. Uncatalyzed as well as Raney Nickel catalyzed runs were also performed for comparison purposes. Reaction temperature was kept at 673 K and total system pressure at 10 MPa in all cases. Weight ratio of solvent to solid loaded was 2:1, the gas phase being either H2 or N2. Independent runs were also performed with cellulose and lignin which are the main wood constituents. Reaction products were characterized by means of gas chromatography and solvent fractionation using specific solvents.
Heavy oil processing in steam and hydrogen plasmas
Authors: Kubanek G. , Munz R. J. , Gauvin W. H.
Published: March 2009

Heavy oil in the form of finely divided spray was reacted with steam and hydrogen plasmas respectively. The heavy oil was preheated to 473 K at a pressure of 2 MPa and fed through pressure atomizers at flow rates between 0.002 and 0.08 m3/h into a dc plasma jet contained in a reactor 20 cm in diameter and 1.5 m long. The hydrogen and steam plasmas had maximum initial temperatures of 6000 K and 3450 K respectively and specific net energy inputs between 0.4 and 12.6 kWh/kg oil were used. With a hydrogen plasma, the heavy oil reacted to form acetylene, ethylene, methane, soot, and pitches, while with a steam plasma, carbon monoxide and dioxide were formed as well. Light liquid hydrocarbons were not in evidence. Increases in the hydrogen (or steam)‐to‐oil ratio and specific energy consumption increased the oil‐to‐gas conversions.
Optimal process parameters for fixed bed adsorption
Authors: Chow D. K.
Published: March 2009

For maximum dynamic adsorptive capacity per unit cost, this study shows optimal breakthrough level, flow velocity, bed length, and adsorbent size for a typical case of aqueous adsorbates through a granular carbon bed, regardless of adsorption mechanism and isotherm. While computed optimal adsorbent sizes are smaller than common ones, other optimal parameter values fall within their respective normal ranges.
Toxic effects of inhibitors in biological wastewater treatment processes
Authors: Tyagi R. D. , Couillard D.
Published: March 2009

Toxic effects of inhibitors on microbial growth in the activated sludge process were demonstrated by a kinetic model. The effects of pH and biomass concentration on the degree of inhibition were described. The applicability of the kinetic model to describe the inhibitory effects with respect to various growth measuring parameters like respiration rate, ATP analysis, first and zero order reaction rates were illustrated. The inhibitory effects of heavy metals on the nitrification and denitrification processes were established. Experimental data from other investigations were used to prove the applicability of the model.
Laminar mixed convection in the entrance region of shrouded arrays of heated rectangular blocks
Authors: Lin Jenn‐Nan , Yen Chen‐Shyong , Chou Fu‐Chu
Published: March 2009

Laminar mixed convection in the entrance region of shrouded arrays of heated rectangular blocks is approximated numerically for large Prandtl number fluids. The problem considered is related to the convective cooling of electronic components mounted on horizontal circuit boards. Two heating conditions are investigated; in case 1, the uniformly heated components are facing upwards and, in case 2, the heated components are facing downwards. Typical fluid streamlines and isotherms, block wall temperature distributions and local Nusselt numbers are presented. It is found that the secondary flow leads to a significant enhancement in heat transfer for cases where the block faces upwards rather than downwards.
Analysis of deactivation disguised kinetics in transport reactors by periodic operation
Authors: Sivakumar S. , Chidambaram M. , Shankar H. S.
Published: March 2009

Deactivation disguised kinetic schemes in an isothermal transport reactor are differentiated by means of periodic operation of the reactor. A periodic rectangular pulse is assumed for the inlet concentration. Three numerical examples are given to demonstrate that the deactivation disguised kinetic models give different conversions under periodic operation.
Mixing and segregation in a liquid fluidized bed of particles with different size and density
Authors: Dutta B. K. , Bhattacharya Suman , Chaudhury S.K , Barman B.
Published: March 2009

Experimental studies have been carried out on fluidization of irregular particle mixtures of different size and density. The mixing and segregation phenomena could be interpreted on the basis of the diffusion model of Kennedy and Bretton. The dependence of computed particle dispersion coefficient on liquid velocity, particle density and size has been discussed.
Reduction kinetics of Fe(III)NTA chelate by sulfite
Authors: Sada E. , Kumazawa H. , Yoshikawa Y. , Rudziński K. J.
Published: March 2009

Kinetics of the reduction of Fe(III)NTA (ferric ion coordinated to nitrilotriacetic acid) by sulfite were studied experimentally in aqueous solutions at 40‐60°C and pH = 3.8‐8.3. The reaction had been claimed to be a regeneration step of Fe(II) in the absorption of nitric oxide into aqueous solutions containing Fe(II)NTA and sulfites. The reaction rate could be expressed as first‐order with respect to the concentration of Fe(III)NTA and of order minus one with respect to the concentration of Fe(II)NTA. The order of reaction with respect to HSO−3 was determined to be unity when the molar ratio of Na2SO3 to Fe(III)NTA was less than 5.
Dispersion dans les lits de particules avec écoulement pulse
Authors: Condoret J. S. , Riba J. P. , Angelino H.
Published: March 2009

Le but de ce travail est l'étude de la modification hydrodynamique, comme par exemple l'état de mélange, engendrée par la superposition de mouvements périodiques à l'écoulement principal dans un réacteur fluide‐solide à lit fixe. Nous nous proposons ici de choisir une description adéquate de l'hydrodynamique du réacteur pulsé, de définir les paramètres impliqués et par une expérimentation spécifique, de déterminer leurs valeurs. Une corrélation pour le calcul du coefficient de dispersion axiale a pu ětre établie:
Studies on the inhomogeneous nature of the silent discharge reactor: Part 3. A multi‐zoned flow model
Authors: Khan A. A.
Published: March 2009

The reaction space of a silent discharge reactor consists of two distinct components, viz. (1) the collection of primary reaction zones (PRZ) or discharge streamers where, under the influence of free electron avalanches, primary electron molecule collisions take place and (2) the remaining reaction space which provides for secondary or quenching reactions between activated species and gas molecules. A flow model based on this concept has been proposed which accounts for the intrinsic chemical activity of the PRZs as well as their random distribution, spatial location, transient nature, and temperature field. Experimental results obtained on laboratory ozonizers have been examined to show the validity of the proposed model.
The behaviour of segregating fluidized beds and its relevance to ash management
Authors: Bemrose C. R. , Botterill J. S. M. , Bridgwater J. , Nienow A. W. , Weiping Yan
Published: March 2009

Visual observation of the movement of particles across a transparent, drilled plate distributor allowed their directional and RMS velocities to be determined. Particles too big and/or dense to be lifted by bubble wakes are moved towards collection zones by the circulating bed material. The minimum fluidizing velocity has to be exceeded by an amount which increases with increasing density and/or number of particles before there is significant transport. Direct and RMS velocities increase linearly with the gas velocity. Circulation is controllable by producing imbalance in the air supplies to different zones of the distributor; tilting the distributor (flow is then up the slope); or use of a spout as a pump. Spouts can remix large/dense particles back into the bulk of the bed. Particles can be selectively withdrawn through a pneumatic off‐take tube.
Correlation of reactivity with chemical structure: Thermal hydrogenation of gas oils
Authors: Gray Murray R. , Khorasheh Farhad , Lana Ivo G. Dalla , Yeniova Hasip
Published: March 2009

The relationship between chemical structure and reactivity for thermal hydroprocessing was studied for five gas oils derived from Alberta bitumens. Chemical structure was characterized by combining data from 1 H and 13 C nuclear magnetic resonance spectroscopy, class fractionation, and elemental analysis to calculate structural parameters. Thermal hydrotreating was performed in a continuous‐flow stirred reactor at 420 and 440°C, 13.9 MPa hydrogen pressure, and 1.5 h1 LHSV. Conversion of the 343–525°C boiling fraction of the gas oils was correlated with the concentration of naphthenic methylene groups in the feed. Formation of methane and ethane was dependent on the degree of condensation of the aromatic rings in the feed oils. Thermal desulfurization was highly correlated with the amount of saturates in the feed, and the aromaticity of the resin fraction. Hydrogen consumption increased with the aromaticity of the gas oil…
The computer‐derivation of thermodynamic equations Part III. Chemical systems
Authors: Jubb D. J. A. , Missen R. W.
Published: March 2009

An algorithm, THERMODER4, based on Jacobians, is presented for automating the symbolic derivation of expressions for thermodynamic derivatives for chemical systems, to complement algorithms given previously for unrestricted simple and complex systems. The algorithm is implemented by a program using an augmented computer‐algebra system together with a microcomputer. Examples are given to illustrate the use of the algorithm in transforming variables and in sensitivity analysis for systems at equilibrium.
Empirical strategies for open‐loop on‐line optimization
Authors: Mcfarlane R. C. , Bacon D. W.
Published: March 2009

Two empirical strategies for open‐loop on‐line optimization are developed as alternatives to the use of mechanistic process models. These strategies are based on on‐line identification of dynamic multi‐input single‐output (MISO) and multi‐input multi‐output (MIMO) models. The steady state gain of these models provides information for steady state optimization. Desirability functions, originally developed for multi‐objective optimization, are utilized as objective function modifiers for constrained on‐line optimization. The integration of dynamic model identification and desirability functions results in an on‐line optimizer which combines fast optimizing speed with the ability to predict future encroachments on constraint boundaries. Corrections to the search direction are based on these predictions, reducing the probability of actual constraint violation.

The optimization strategies are tested by simulation on nonlinear multivariable interacting systems at two levels of complexity: a CSTR supporting a multiple reaction and a fluid catalytic cracker. Both methods were effective in avoiding violation of constraints but the MIMO strategy required fewer steps to reach an optimum and was less prone to generate a nonfeasible optimization step.
Heat transfer in a continuous bubble column
Authors: Chen B. H.
Published: March 2009

The effective thermal conductivity ke was measured for a continuous bubble column operating within the bubbly flow regime. ke was found to be independent of liquid flow rate but strongly dependent on gas flow rate and physical properties of the liquid phase over the ranges 0.1>uG>4 cm/s, 0>uL>3.4 cm/s, 0.00096> μ >0.0028 kg/m μ s and 0.047 >σ>0.072 N/m.
The spouting regime map, bubbling characteristics and bed expansion of deep beds of large hollow polyethylene spheres
Authors: Zamora R. , Littman H. , Morgan M. H.
Published: March 2009

The high velocity spouting regime of a deep bed containing 9.6 mm hollow polyethylene spheres of density 394 kg/m3 was investigated in a 152.4 mm flat bottom cylindrical half column with a 50.8 mm inlet. A bed height vs gas velocity regime diagram is presented showing the conditions under which type II spouting is observed. The transition velocity from bubbling to type II spouting is determined using the autocorrelation of the pressure fluctuations in the bed. The bubbling characteristics of the bed are described. Bed expansion in bubbling and type II spouted beds are reported.
Pressure equalization in diffusion cells
Authors: Trigg David , Hudgins R. R. , Silveston P. L.
Published: March 2009

Design of a pressure equalization device is described that imposes a fixed pressure to minimize the relative importance of pressure fluctuations in steady state, counterdiffusion measurements employing a Wicke–Kallenbach diffusion cell. The success of this design is shown in observing gas diffusion in a liquid‐filled, porous, sintered–steel plate.
Approximate solutions of effectiveness factor based on bulk conditions
Authors: Goto S. , Ito H.
Published: March 2009

A simple method to obtain approximate solutions of the catalytic effectiveness factor from a specified Thiele modulus is proposed for isothermal pellets with significant external temperature and concentration gradients. The approximate solutions are in good agreement with exact solutions for various reaction orders and shapes.
Experimental measurements of local axial gas velocity and void fraction in simulated pwr steam generator rod bundles
Authors: Moujaes S. F. , Dougall R. S.
Published: March 2009

A dual spherical tipped optical fiber probe is used to obtain new data on local axial gas velocity and void fraction in a 4 × 3 rod bundle simulating a PWR steam generator. The average volumetric fluxes used were Jg = 1.52 ‐ 2.44 m/s and J, = 0.47 ‐ 0.68 m/s. Significant variations of Vg and α were found to exist downstream from the support plate. However the α range did not show any significant change between the flow holes and that downstream position, while Vg showed a more substantial variation. Values of Vg and α were very different between locations in the clearance gap around the tubes and that in the main flow holes. The gas flow rate was estimated to be only between 1–2.0% of that in the flow holes which could explain in part the existence of deposits in the clearance gap, due to decreased liquid velocity, leading eventually to tube denting in a PWR application.
Continuous crystallization of potash alum: MSMPR kinetics
Authors: Jones A. G. , Mydlarz J.
Published: March 2009

The crystallization kinetics of potash alum (aluminium potassium sulphate) from aqueous and aqueous acetone solutions respectively in a continuous mixed‐suspension, mixed‐product‐removal (MSMPR) crystallizer (capacity 4 L) are reported. Growth and nucleation rates are determined by direct model estimation via the population balance analysis of crystal size distribution measured using laser light scattering and sieve analysis.

The overall growth rate during drowning‐out precipitation strongly decreases with increasing acetone concentration in the crystallizing solution. Nucleation rates evaluated at zero‐size, however, are virtually unaffected while the “effective” nucleation rates are strongly increased by the presence of acetone with a reduction in the supersaturation order. Magma density dependence is approximately first order during cooling crystallization while a somewhat lower dependence is detected during drowning‐out precipitation.
An analysis of the elution curve in preparative chromatography with moving feed ports
Authors: Kubota Katsuyuki , Hayashi Shinya
Published: March 2009

The present work deals with the mathematical analysis of the elution curve in preparative chromatography with moving feed ports. To predict the elution curve for this moving feed mode, simple differential equations for mass transfer were employed and solved by using algorithms based on the Plate Theory and iteration methods. As a result, the least chromatographic band spreading was found on the moving feed mode rather than the non‐moving feed mode only if mass transfer resistance between the phases does not participate in the adsorption process. On the other hand, when the mass transfer is not very rapid, the chromatographic performance of the moving feed mode was found to be compatible with that of the non‐moving feed mode.
A three‐parameter cubic equation of state for fluids and fluid mixtures
Authors: Tsai Fuan‐Nan , Jan Dong‐Syau
Published: March 2009

A new cubic equation of state with three parameters is developed. The substance‐dependent critical compressibility factor, ζ, and the temperature‐dependent parameter, α, were correlated in terms of the acentric factor and reduced temperature. The P‐V‐T relationships, vapor pressures, volumes, and enthalpy departures of pure substances, and the compressibility factors, enthalpy departures, and vapor‐liquid equilibria of mixtures were calculated with the proposed equation. Comparison of the calculated results with experimental data shows that the proposed equation is accurate enough to be applied for design purposes.
Taking advantage of available cubic equations of state
Authors: Adachi Yoshinori , Lu Benjamin C.‐Y. , Sugie Hidezumi
Published: March 2009

All available simple cubic equations of state (EOS) are developed for specific representations. An effort has been made to take advantage of these existing equations for binary vapor‐liquid equilibrium (VLE) as well as density calculations by assigning different EOS to different components of the mixture under consideration. A four‐parameter cubic equation was used for combining the equations in the calculation. The effect of substance‐dependent Ωac on vapor‐liquid equilibrium calculations was further investigated, using two sets of mixing rules. A criterion for selection of equations for VLE calculation by means of the proposed approach was suggested. The improvement in the prediction of liquid volumes for binary mixtures based on the fitting of pure component liquid volumes was very satisfactory.
Solubility of propylene gas in octane and various polar solvents
Authors: Hayduk W. , Wong C.‐F.
Published: March 2009

Propene gas solubilities at 101.3 kPa pressure are reported in n‐octane, chlorobenzene, acetone, acetic acid, ethyl acetate, n‐butanol, N‐N‐dimethyl formamide (DMF) and ethylene glycol for a range of temperatures. These data, along with data from the literature, were used to show the qualitative effects of unsaturation of the gas component on the solubility in various solvents ranging from non‐polar to highly polar and associated solvents. This involved a comparison, when data were available, of the solubilities of ethane, ethylene and acetylene, then of butane, isobutane, isobutylene, trans‐2‐butene and 1,3‐butadiene as well as of propane and propene (propylene). The differences in solubilities could be explained using solubilities expressed as a molecular interaction parameter (mip) and by identifying several different types of molecular interactions. For associating solvents these effects can be summarized as follows:

mip of acetylene > mip of ethylene > mip of ethane, also mip of propylene > mip of propane and mip of butadiene > mip of isobutylene≥ mip of trans‐2‐butylene > mip of butane > mip of isobutane.
Synthesis of model‐based controllers for an autothermal reactor
Authors: Chylla Richard W. , Çlinar Ali
Published: March 2009

Model‐based controllers for a bench scale autothermal tubular packed‐bed reactor have been formulated using the Internal Model Control (IMC) approach. The Structural Dominance Analysis technique has been used in developing the reduced‐order models. Controller performance at robust and sensitive steady states have been assessed through simulations and experiments. Both PI and model‐based controllers can regulate reactor operation at robust steady states, but only third order IMC controllers are able to regulate reactor operation at the sensitive steady state.
An improved light attenuation technique for measuring large interfacial areas
Authors: Kasireddy V. K. , Al Taweel A. M.
Published: March 2009

A laser‐based light attenuation technique was successfully used to measure interfacial areas as high as 5832 m2/m3 and Sauter mean bubble diameter varying between 50 and 5600 μm. Good agreement between this approach and the photographic technique was obtained particularly at low gas holdups.
Production of uniform drops of viscous liquids using a coaxial airstream
Authors: Blysniuk John W. , Sefton Michael V.
Published: March 2009

The effect of coaxial airstream velocity on the size of polymer solution droplets (300–1000 μm in diameter) extruded from a tapered needle have been measured and shown to be consistent with a force balance that equates the drag force to surface tension. However, droplet diameter was also dependent on polymer solution viscosity at higher air velocities (> 22 m/s), indicating that viscous dissipation forces must also be considered in the force balance. These results are relevant to the design of devices used to microencapsulate live mammalian cells which are based on similar extrusion techniques.
Isobaric vapor—liquid equilibria for binary systems composed of methyl butanoate with ethanol and with propan‐1‐ol at 114.66 and 127.99 kpa
Authors: Ortega Juan , Susial Pedro
Published: March 2009

Vapor‐liquid equilibrium data for the binary systems methyl butanoate/ethanol and methyl butanoate/propan‐l‐ol at pressures of 114.66 and 127.99 kPa are presented. Both mixtures yield an azeotrope, the compositions (ester) of which decrease quasi‐linearly as the pressure increases. The experimental data for all the binary mixtures were fitted to a suitable equation and then used for comparison with predictions by ASOG and UNIFAC methods. These group contribution models give a good estimation of activity coefficients with an overall mean error less than 5% for all cases.
An industrial cell biologist's wish list
Authors: Seaver Sally S.
Published: March 2009

The current state of protein production by eukaryotic cells in culture is reviewed by a cell biologist with an eye towards areas that could benefit from more work by chemical engineers. The basic question of how the type of bioreactor influences cell productivity has not been answered. We are still learning how to optimize protein production in all types of bioreactors. Recent examples show that optimization can increase productivity over 10‐fold. Support work needs to be done to determine the limits of individual cell productivity. Basic cell metabolism work needs to be done in serum‐free medium to make it generally applicable. Only then can better bioreactors be designed with useful probes to monitor important substances.
Insect cell cultivation techniques for the production of high‐valued products
Authors: Goosen Mattheus F. A.
Published: March 2009

The large scale cultivation of insect cells will likely play an increasingly important role for the commercial production of bioproducts. While much research work has been done on the engineering aspects of insect cell suspension culture, many questions remain unanswered (i.e. the nature of bubble damage in sparged reactors, shear sensitivity and adaptation of cells; the use of serum‐free medium). In addition, insect cell immobilization may become a suitable technique for enhancing cell densities and product concentrations. This article presents a brief critical review of the development of insect cell suspension culture techniques for the production of insect pathogenic viruses and recombinant proteins.The problems of culturing microencapsulated insect cells, infected with a temperature sensitive baculovirus, also is discussed.
Linear displacement of a wetting fluid by an immiscible non‐wetting fluid in a porous medium: A predictive algorithm
Authors: Kiriakidis D. G. , Mitsoulis E. , Neale G. H.
Published: March 2009

The linear displacement of a wetting fluid by an immiscible non‐wetting fluid in a two‐dimensional porous medium composed of a network of sites multi‐connected by bonds has been simulated mathematically. The algorithm involves Monte Carlo decision making, random walks and principles of the percolation theory. The algorithm described in the present work successfully predicts the three distinct behaviours of immiscible displacement in porous media. This algorithm is tested against experiments available in the literature for two‐dimensional porous media. The agreement between the numerical results and the experiments is very good.
Adaptive control of hydrodynamic holdup in a karr extraction column
Authors: Camurdan M. C. , Taylor P. A. , Baird M. H. I.
Published: March 2009

An application of a Clarke‐Gawthrop self tuning regulator to control the dispersed phase holdup in a Karr reciprocating plate extraction column is presented. The frequency of reciprocation was used to control holdup because of its speed of response and low cost. The relationship between the frequency of reciprocation and the dispersed phase holdup is highly nonlinear, and, therefore an adaptive controller has to be used to control this process. Previous work (Kusuma, 1981) on holdup control has been extended to cover a wider range of operating conditions and to prevent covariance windup by including an empirical discounting factor. The experimental results focus on the operating region near to flooding since this is the most difficult to control and is often closest to the optimal operating point. The advantages and limitations of the empirical discounting factor are discussed.
Emulsification of a viscous monomer mix: Particle size and size distribution
Authors: Chaffey Charles E. , Tasalloti Suzanne , Paine Anthony J.
Published: March 2009

A non‐Newtonian mixture of monomers, their copolymer and pigment was dispersed into water with emulsifier by a rotor‐stator homogenizer (Brinkmann Polytron). Volume median diameters d50 of the droplets, measured by Coulter Counter or optical microscopy, were typically 4–20 μm; d50 was about inversely proportional to monomer fraction (0.2 to 1.0), or to rotor speed (4000 to 11000 rpm). Increasing the emulsifier from 0.1 % to 3% roughly halved d50; volume fraction of organic phase had little effect. Turbulent dispersion theory (Calabrese et al., 1986a, b), adapted to non‐Newtonian drops, represented the data but with different numerical constants. A high geometric standard deviation, around 1.7 but increasing slightly as monomer fraction decreased, may be due to non‐uniform turbulence and to the complexity of breakup at high viscosity.
Horizontal wells and steam‐assisted gravity drainage
Authors: Butler R. M.
Published: March 2009

Petroleum can be produced more efficiently using horizontal wells instead of conventional wells. For a typical 16 hectare well spacing, the pressure drawdown is as small as one‐fiftieth of that for conventional wells.

In some cases, where coning is a problem in conventional production, horizontal wells allow operation with much less coproduction of the displacing fluid.

In the thermal recovery of bitumen and heavy oils, the Steam‐Assisted Gravity Drainage process with horizontal production wells allows the systematic sweeping of the reservoir with economic production rates and without steam bypass.

This paper described and reviews the application of horizontal wells to the production of heavy crude oils and bitumen by both non‐thermal and thermal methods.
Application of the rotating disk method to the study of bitumen dissolution into organic solvents
Authors: Ulrich R. K. , Koppaiah M. K. , Majmudar V. K.
Published: March 2009

The rotating disk system is demonstrated as a tool for performing studies of the dissolution rate of bitumen into organic solvents. Mass transfer coefficients to the rotating disk are constant in position and time can be made comparable to coefficients for sand particles in agitated liquids by adjusting the rotation rate. Data is presented for bitumen dissolution into pentane, hexane, heptane, toluene and oleic acid. Increasing the level of dissolved bitumen in the solvent decreases the bitumen dissolution flux primarily due to the increase in solvent viscosity.
Kinetic modelling of the catalytic conversion of synthesis gas
Authors: Simard F. , Mahay A. , Jean G. , Delasa H.
Published: March 2009

A kinetic study for the one‐step conversion of synthesis gas to gasoline on a ZnO–Cr2O3–ZSM‐5 catalyst is described. On this catalyst, three reactions are involved in the overall transformation of synthesis gas: the methanol synthesis, the conversion of methanol to hydrocarbons and the water–gas shift reaction. Under the operating conditions selected for the study, it was found that the water–gas shift was at equilibrium and the methanol was completely converted to hydrocarbons. Consequently, it was postulated that the kinetics of the limiting reaction step, the methanol synthesis on the ZnO–Cr2O3 component, was the one that controls the overall reaction rate. Three kinetic model equations describing the rate of synthesis gas conversion on the bifunctional catalyst, were considered to fit the data of the experimental runs performed in a Berty well‐mixed reactor. Those equations were derived under very special conditions where the methanol decomposition term could be neglected. It was also observed that in the kinetic equations a term involving the fugacity of CO2 was required to predict the rate properly. The catalyst deactivation was also taken into account in the analysis.
La décomposition thermique du n‐decane en présence de vapeur dceau vers 720°C
Authors: Billaud F. , Elyahyaoui K. , Baronnet F.
Published: March 2009

The thermal degradation of n‐decane in a plug reactor is studied at about 720°C. Products not exclusively of primary type were all titrated using a gas phase capillary chromatography method. The major primary products are ethylene, methane, propene and hydrogen. Ethylene selectivity is approximately 35% at lower passage times (40 to 160 ms). A chain radical‐based theoretical mechanism has been used to account for all reaction products qualitatively and to represent the associated stoichiometrics for the degradation of initial alcane.
Effect of sulfite on reduction kinetics of Fe(III)NTA chelate
Authors: Sada E. , Kumazawa H. , Suchecki T. T.
Published: March 2009

The reduction of Fe(III)NTA (ferric ion coordinated to nitrilotriacetic acid) by sulfite has been found to be first‐order with respect to Fe(III)NTA and of order minus one with respect to Fe(II)NTA (one of the reaction products). The order of reaction with respect to HSO−3 has been determined to be unity when the molar ratio of Na2SO3 to total Fe(III) is less than five. In this paper, the role of sulfite in the reduction scheme is reconsidered, and the reduction rate expression in which the coordination of Fe3+ to HSO−3 is incorporated, is newly presented. The proposed rate equation covers all reaction data for molar ratios of Na2SO3 to total Fe(III) in the range of 1 to 25.
Mass transfer and holdup in gas‐liquid cocurrent flow packed beds containing water‐repellent particles
Authors: Goto Shigeo , Saikawa Keichiro , Gaspillo P. D.
Published: March 2009

Water‐repellent particles were prepared by spraying polytetrafluoroethylene (PTFE) on activated carbon. Gas‐liquid volumetric mass transfer coefficient and holdup were determined in gas‐liquid cocurrent upflow and downflow packed beds from the measurements of gas desorption and volume, respectively. As the PTFE loading increased, the gas‐liquid volumetric mass transfer coefficients in both upflow and downflow modes were enhanced. Gas holdup in the upflow mode increased with the PTFE loading, while the dynamic liquid holdup in the downflow mode decreased. The enhancement of the mass transfer rate from gas to liquid can be explained by the effect of water‐repellency on the surface of activated carbon.
Solids distribution in slurry flow in a linear manifold with a horizontal approach
Authors: Foster J. , Nasr‐El‐Din H. A. , Masliyah J. H.
Published: March 2009

An experimental study was conducted to examine solids distribution in branches of a linear manifold having a horizontal approach. The manifold was designed to maintain approximately a constant slurry velocity upstream of each branch. Solids concentration in the branches was measured for various manifold orientations (upwards, side and downwards) and upstream conditions.

Semi‐empirical correlations for the three orientations were developed to predict a branch concentration ratio. This ratio was dependent upon the branch flow ratio, the particle inertia parameter and the vertical solids concentration profile upstream of the branch. The agreement between the experimental and the predicted branch concentration ratio was fairly good.
The catalytic hydrotreatment of peat pyrolysate oils
Authors: Oasmaa Anja , Boocock David G. B.
Published: March 2009

A 65 wt % yield of hexane‐soluble liquid, containing 83% of the feed carbon, was obtained when Finnish Carex‐peat pyrolysate was hydrotreated batchwise (21.5 MPa for two hours at 390°C with 10 wt % catalyst, 4% CoO/15.5% MoO3 on γ‐alumina). Oxygen content was lowered from 22% to 3% in the process. Nitrogen and sulphur contents of the product were 4.3% and 0.10%, respectively. Straight‐chain material predominated in the upgraded product and C14‐C29 n‐alkanes have been identified along with some phenols. The peat pyrolysate is also predominantly straight‐chain material, but contains polar functionalities such as the carboxyl group.
The behaviour of large gas bubbles at a liquid‐liquid interface. Part 2: Liquid entrainment
Authors: Shaw J. M. , Konduru R.
Published: March 2009

The roles played by large gas bubbles in the generation and coalescence of liquid drops at a liquid‐liquid interface are elucidated. The amount of lower liquid entrained by individual bubbles and the resulting drop size distributions in the upper liquid phase are quantified for the three phase system: sunflower oil + 50 wt % decane, water + 50 wt % sugar, air, and qualitative theoretical models are presented. Drops settling to the interface were found to coalesce rapidly and bubble flux had no apparent effect on the rate of drop coalescence at the liquid‐liquid interface.