bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation of proteins and peptides from yeastolate and subsequent impurity testing of drug product
Authors: Dick Lawrence W. , Kakaley Jeffrey A. , Mahon David , Qiu Difei , Cheng Kuang‐Chuan
Published: March 2009

Hydrolysates play an important role in modern biological production. These mixtures are mostly undefined and contain a mixture of proteins, peptides, and amino acids along with other non–amino acid‐based components. Recently, there has been an interest in defining and sequencing proteins and peptides in these hydrolysates to subsequently develop an assay to ensure removal during product purification. This work investigates an ultrafiltrate of yeastolate to determine whether any protein is present. Size exclusion chromatography indicated a possible high molecular weight component (>10 kDa). This suspected high molecular weight fraction was collected and investigated. It was determined that this fraction consists of nucleic acids; and no protein was detected using sensitive modern techniques including HPLC, mass spectrometry, and SDS‐PAGE. Next, five unique, yeast‐specific peptides were identified, sequenced, and confirmed. Finally, an impurity assay for any residual yeast specific peptides was developed and the analytical metrics were determined including accuracy, precision, linearity, range, and limits of detection and quantitation. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009
IgA response of BALB/c mice to orally administered Salmonella typhimurium flagellin‐displaying T2 bacteriophages
Authors: Synnott Aidan , Ohshima Kazuhito , Nakai Yutaka , Tanji Yasunori
Published: March 2009

Salmonella typhimurium antigens were displayed on the capsid of a T2 bacteriophage to explore the potential of phage display for an oral vaccine. Segments of the flagellin proteins FliC (H1 antigen) and FljB (H2) were fused to the N‐terminal of T2 phage SOC to give two recombinant phages, T2FliCm and T2FljBm. Over 14 days, 19 BALB/c mice were orally administered twice, either with purified recombinant FliCm and FljBm protein, or T2FliCm and T2FljBm with or without host Escherichia coli. Feces were sampled over 10 weeks and examined for phage by plaque assay and for the presence of mucosal IgA by ELISA. Relatively few phages were detected relative to the amount administered (up to 8.21 × 103 PFU/g faeces) and none were detected five days after initial administration. The administration of a large number of phages appeared to cause no clinical symptoms. IgA concentration in feces peaked around four weeks after the second administration and subsided after eight weeks. The highest relative titers were observed in the protein group (0.37% for anti‐FliCm and 0.22% for anti‐FljBm) and the mouse group which received no E. coli (0.33% and 0.35%) despite the theoretical amount of protein contained in a phage dose being at least 80–465 times lower than the protein dose administered. The possibility that the immuno‐stimulatory properties of the phage create an adjuvant effect to enhance the immunogenic properties of the displayed proteins is discussed. We conclude that phage may be valuable as a vector for oral vaccines. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009
The landscape of policies and practices that support student preparation and success
Authors: Bueschel Andrea Conklin
Published: March 2009

This chapter surveys the educational landscape to describe current policies and practices that affect student preparation for and success in community college, ranging from national trends and state‐level policies to individual classroom projects.
Looking ahead: Synthesizing what we know about national, regional, and local efforts to improve student preparation and success
Authors: Jez Sujin , Venezia Andrea
Published: March 2009

The many projects, policies, and practices discussed in this volume suggest promising ideas for improving student success both before matriculation and in developmental education in community colleges. Ideally, improvement in the former will reduce the need for the latter, but until that happens, the goal will be to promote effective strategies for both. In this concluding chapter, the editors combine the information learned from the two strands within this volume to pose some final thoughts and next steps for future work in this area.
Prediction of axial velocity profiles and solids hold‐up in a rotary kiln
Authors: Sai P. S. T. , Surender G. D. , Damodaran A. D.
Published: March 2009

Axial bed depth profiles were experimentally measured in a rotary kiln containing ilmenite particles under steady state and transient conditions. The variables include feed rate of solids, inclination and rotational speed of the kiln. and dam height. The variation of the axial velocity with kiln axis was estimated. The semi‐experimental model proposed by Perron and Bui (1990) was modified to include the effect of the variables of the present study. The mean residence time of solids was estimated from the fractional hold‐up and expressed in terms of the process variables. The transients induced by a step change in any of the operating conditions were measured as variation of discharge rate of solids with time.
Solubility of anthraquinone in alkaline solutions of sodium sulfide
Authors: Revenga J. , Rodríguez F. , Tijero J.
Published: March 2009

The reduction of anthraquinone (AQ) with alkaline solutions of sodium sulfide, which takes place in the kraft pulping process, has been studied. The reduction product is the disodium salt of 9,10‐dihydroxyanthracene (Na2AQ). A 24 factorial design has been used to check the effects of sodium sulfide, anthraquinone and sodium hydroxide concentrations and temperature on the reaction. From statistical results, it has been concluded that the concentration of reducing agent has a limiting effect on Na2AQ yield, while the temperature has a negative effect because it favours the oxidation of sodium sulfide in alkaline solutions. Therefore, a maximum reduction of quinone can be obtained with the highest concentration of reagents and low temperatures.
The best performance of inclined thermal diffusion columns of the frazier scheme
Authors: Yeh Ho‐Ming
Published: March 2009

The equations for the best angles of inclination for maximum separation, maximum production rate and minimum column length in inclined flat‐plate thermal‐diffusion columns of the Frazier scheme, have been derived. Considerable improvement in performance is obtained when a Frazier scheme is operated at the best corresponding angle of inclination, especially for the schemes of high column number.
Viscosity of the binary systems containing trifluoroethanol, water and tetraethylene glycol dimethyl ether. Prediction of the ternary viscosity from binary data
Authors: Olivé F. , Chaudhari S. K. , Patil K. R. , Coronas A.
Published: March 2009

Kinematic viscosities were measured over the entire range of composition and at atmospheric pressure for the binary systems trifluoroethanol (TFE)‐H2O, TFE‐tetraethylene glycol dimethyl ether (TEGDME), and TEGDME‐H2O from 293.15 to 333.15 K. The data were fitted by the Stephan and Heckenbergber (1989) correlation, which accounts for the dependence on temperature and mixture composition.

Methods for predicting ternary excess viscosities from excess viscosity data for the three binary mixtures involved are examined and tested for the system TFE‐H2O‐TEGDME at 303.15 K by comparing predicted and experimental data. The empirical correlation of Colinet (1967) is shown to be the best for this system.
Enhancement of the thermal performance of a wet cooling tower
Authors: El‐Dessouky Hisham
Published: March 2009

The effect of packing roughness on the thermal and hydraulic performance of a packed bed wet cooling tower were investigated experimentally. Tower enhancement ratio and air‐side pressure drop ratio were determined as functions of packing relative roughness at different values of water inlet temperature, and water‐to‐air mass flux ratio. The packing used was glass Raschig rings 10 mm thick and 10 mm in diameter. The surface roughness was changed by adhering sand papers of different roughness to the outside surface of the packing.

The experimental data showed that an increase in the surface relative roughness from 1 to 5.62 can increase both the tower enhancement ratio and the air side pressure drop ratio up to 146% and 142%, respectively. The effect of the surface relative roughness is more pronounced at lower values of water‐to‐air mass flux ratio and at higher values of hot water inlet temperature. Also, a new analytical expression was developed to calculate the cooling tower characteristics.
Mathematical modelling of the transient behaviour of cstrs with reactive particulates: Part 2 — Application to pyrite pressure oxidation
Authors: Rubisov Dmitri H. , Papangelakis Vladimiros G.
Published: March 2009

A population balance based transient reactor model is applied to a particulate process employed in the hydrometallurgical industry. The process is the pressure oxidation of pyritic concentrates, pertinent to the treatment of refractory gold materials. The chemical reaction system involves first an oxygen gas to aqueous mass transfer step, followed by a chemical reaction on the surface of mineral particles. The chemical reactor stimulated is a multi‐stage continuous autoclave with variable compartment size. The model accounts for recycling oxidized solids, as well as for venting the gas phase. A complex system of partial and non‐linear ordinary differential equations is rendered dimensionless and solved by a method developed previously using the Mathematica® software. The transient response of the reactor to different modes of reactor start‐up, as well as the response to a step change of a key variable, are examined. The validity of the steady‐state solution is assessed by comparing it to previous modelling attempts.
Liquid‐liquid equilibria of (MTBE or TAME) + ethanol + water mixtures
Authors: Arce Alberto , Blanco Manuel , Riveiro Rafael , Vidal Isabel
Published: March 2009

Experimental liquid‐liquid equilibrium data obtained at 25 and 35°C for ternary mixtures of MTBE + ethanol + water, and at 25, 35 and 45°C for ternary mixtures of TAME + ethanol + water, were satisfactorily fitted with NRTL and UNI‐QUAC equations using the correlation program developed by Sørensen (1980).
A method for the evaluation of microbial growth in a trickling bed reactor
Authors: Escot A. , Chavarie C. , Mayer R. , Ramsay J.
Published: March 2009

A method to evaluate microbial activity and growth in an eight‐stage, trickling bed reactor, packed with peat particles, was developed. Steady‐state measurements were made of the substrate degradation rate, based on the change in chemical oxygen demand (COD), and the biological rate of oxygen consumption based on the difference between inlet and outlet oxygen concentrations in the gas phase. From these values, a global yield coefficient (Yx/s) was evaluated in terms of g of total biomass produced per g of COD consumed. Using this method, Yx/s was 0.23 ± 0.03 from days 10 to 23. This correlated well with a Yx/s of 0.29 g of biomass produced per g of substrate consumed as determined in the first stage of an eight‐stage reactor. This method could be applied to suspension culture and fixed bed bioreactors where obtaining a homogeneous, biomass sample is difficult.
In situ laser raman spectroscopy during sequential oxidizing and reducing conditions for a vanadium‐phosphorous‐oxide catalyst
Authors: Soejarto A. D. , Schrader G. L. , Coulston G. W.
Published: March 2009

A VPO catalyst prepared in an organic medium has been studied by in situ laser Raman spectroscopy for n‐butane oxidation to maleic anhydride. Data could be obtained at low laser power and brief collection times. Raman characterization during continuous flow (steady‐state) studies revealed that (VO)2P2O7 was present. Sequential oxidizing (10% O2 in N2) and reducing (2% n‐butane in N2) conditions were explored at 350°C and 400°C. These cycling (unsteady‐state) operations revealed that formation of V(5+) phases was enhanced during oxidizing conditions. The intensity of Raman bands due to (VO)2P2O7 increased during reducing conditions.
The non‐linear behaviour of the NO‐H2 reaction over Rh surfaces
Authors: Janssen N.M.H. , Neill J. A. , Cobden P. D. , Nieuwenhuys B. E. , Ikai M. , Tanaka K.
Published: March 2009

In this paper we describe the non‐linearity of the NO‐H2 reaction over Rh surfaces. Rate oscillations have been observed over a stepped (111) surface with (100) steps, (Rh(533) at low pressures (10−4 Pa) below 500 K, while no oscillations could be observed under these conditions over a Rh(100) surface and a stepped (100) surface with (111) steps, Rh(711). The thermal stability of the N atoms formed during the reaction explains the observed structure sensitivity. Moreover, the results suggest that diffusion of N atoms is needed to synchronise the rate oscillations, a process that is absent on Rh(100) and Rh(711).
Effect of tap spacing on observed differential pressure fluctuations in a pneumatic transport line
Authors: Beeckmans J. M. , Usta B. , Zhu J.‐X.
Published: March 2009

The standard deviation of differential pressure fluctuations between pressure taps in a 31.7 mm i.d. vertical downer was found to be proportional to the square root of the distance between the taps when measured under otherwise constant conditions. This finding confirms the prediction of a theoretical model based on the Central Limit Theorem of sampling statistics. Although the paper only presents experimental confirmation for downward flow, the theoretical model should be valid for flows in all orientations. Except at very low solids flows, the pressure gradient was found to be positive in the flow direction, indicating that rise in pressure due to static pressure more than compensated for frictional pressure losses.
Development of flow from multiple‐jet burners
Authors: Yimer J. , Becker H. A. , Grandmaison E. W.
Published: March 2009

Multiple‐jet cold‐model burners aerodynamically simulating a class of industrial burners were studied. The fields of mean velocity and velocity fluctuation intensity were measured with Pitot probes. The validity of an effective source diameter as a characteristic length scale is demonstrated. Beyond the nearfield, the flows are virtually the same, and similar to a round jet from a single source. In the nearfield, individual structures peculiar to each burner are observed. The results support the mathematical modelling, for some types of simulations, of flows from complex burners as point‐source jets, affording a substantial simplification of the treatment.
Dynamics of active sites transformation in HDS‐HDA catalyst
Authors: Ostrovskii N. M. , Gulyaev K. S. , Reutova O. A. , Startsev A. N.
Published: March 2009

Benzene hydrogenation in steady‐state and unsteady‐state regimes over sulfide Ni‐W/γ‐Al2O3 catalyst is studied. The mechanism and dynamic model of hydrogenation and hydrogenolysis active sites transformation are proposed. The reactions were shown to be quasi steady‐state ones with slow poisoning of both hydrogenation and hydrogenolysis active sites by the formation of intermediate surface compounds of sulfur. The dynamic behavior was described by the proposed model with sufficient accuracy.
Dépôt chimique CVD de silicium dopé in situ au phosphore. Partie 1: Etude expérimentale
Authors: Tounsi Adnen , Duverneuil Patrick , Couderc Jean‐Pierre , Scheid Emmanuel
Published: March 2009

La réalisation de couches de silicium dopé in situ au phosphore par la technique de dépǒt chimique à partir de la phase vapeur (CVD) est encore mal maǐtrisée par les industries de la microélectronique. Des hétérogénéïtés importantes d'épaisseur sont constatées sur plaquette et sur charge, limitant grandement l'utilisation d'un tel procédé. Une étude expérimentale de ce dépǒt est réalisée. Les influences de nombreux paramètres (température, pression, composition de l'alimentation) sont étudiées en terme d'épaisseur et d'uniformité de dépǒt ainsi qu'en terme de structure cristalline et de résistivité. Les potentialités et les mécanismes mis en jeu sont mis en évidence.
On line estimation of matte grade in a copper smelter
Authors: Cain Shelley L. , Budman Hector M. , Pritzker Mark
Published: March 2009

This study deals with the design of an inferential estimator to predict matte grade in a copper smelter. A novel mathematical model for the dynamics of the smelter is presented and used as the basis of the on‐line estimators. Two different types of estimators are proposed: an estimator with fixed parameters and an estimator with parameters which adapt in time based on infrequent process measurements. Several configurations of the adaptive and fixed estimators, based on different combinations of parameters and measurements, have been designed and compared to plant data. Conclusions are drawn regarding the most accurate configuration.
The effect of flow reversal on solids suspension in agitated vessels
Authors: Myers Kevin J. , Bakker André , Corpstein Robert R.
Published: March 2009

Flow patterns in agitated vessels are influenced by geometry, particularly impeller diameter and impeller off‐bottom clearance. Large impellers and/or high off‐bottom clearances lead to reversed flow in which the flow at the base of the vessel is radially‐inward as opposed to radially‐outward as expected with axial‐flow impellers. Reversed flow is detrimental in solids suspension agitation because inordinately high torque and power are required to achieve suspension. This work experimentally characterizes the effect of flow reversal on solids suspension performance, including guidelines for avoiding flow reversal with straight‐blade turbines, pitched‐blade turbines, and high‐efficiency impellers.
Kinetics of organochlorine removal from bleached kraft pulp mill effluent during biological treatment
Authors: Tripathi Chandra S. , Allen D. Grant
Published: March 2009

Batch biodegradation kinetic studies were conducted with various bleached kraft pulp mill effluents containing organically bound chlorine measured as adsorbable organic halogen (AOX) (6.0 ‐ 35 mg Cl/L). Biomass, generated in both a continuous bench scale reactor and a mill scale activated sludge system, at various concentrations (0.4 ‐ 3.1 g VSS/L) was added to various effluents (about 70% ClO2 substitution).

AOX removal kinetics were best described by a simple recalcitrant first order model: ‐ dS/dt = ks,1X(S‐S∞), where S and S∞ are AOX concentrations (mg Cl/L) at time t and t∞, respectively, ks,1 is the AOX removal rate constant (L/g VSS.h) and X is the biomass concentration (g VSS/L). The model indicated a constant non‐biodegradable fraction of AOX (0.4 mg of AOX per mg of influent AOX) and was able to predict the effect of dilution on AOX removal with a single value of ks,1 (0.13 L /g VSS.h). The degradation constants (0.16 L /g VSS.h) in the absence of effluent from the neutral sewer (i.e. for a mixture of acidic and alkaline effluent only) were significantly higher than those for whole mill effluent.
MD‐CD interaction modeling and control of paper machines
Authors: Kwok K. Ezra , Li Ping
Published: March 2009

For better quality control of paper machines, variations in the machine direction (MD), cross‐machine direction (CD) and their inherent interactions should be minimized. In this paper, a dynamic MD‐CD interaction model is developed by relating the effect of MD dry basis weight to the CD profile. Based on this model, a combined MD‐CD generalized predictive control strategy is proposed to handle the strong MD‐CD interaction. A set of industrial data was used to identify the interaction model. Results from closed‐loop simulation of the interaction model under the proposed control strategy show that a significant improvement in CD control during a grade change can be achieved.
Multimodel‐based minimum bias control of a benchmark paper machine process
Authors: Liu D. Y. , Fisher D. G. , Shah S. L. , Liu X.
Published: March 2009

This paper presents a multimodel‐based minimum bias (MB), long‐range predictive control algorithm that minimizes the bias in the output using a multiobjective optimization method.

To enhance the robustness of the control system, the MB control scheme is extended to the multimodel‐ or multicontroller‐ based MB control scheme, which establishes several models simultaneously. Models with relatively small prediction errors are selected to form a group of acceptable models. The final control is chosen to be the weighted average of the MB controls. Models with significant or large errors are reinitialized.

The proposed MB control scheme is evaluated by application to a paper machine benchmark problem and its performance is compared with that of other controllers.
Fundamental characteristics of combined impingement and through air drying of paper
Authors: Chen G. , Crotogino R. H. , Douglas W. J. M.
Published: March 2009

An experimental facility was developed to determine fundamental characteristics of combined impingement and through air drying of paper. Removal of impingement boundary layer humidity by through flow makes both components of the combined process nonadiabatic, complicating the analysis. Water removal rate curves for both the impingement exhaust and the through flow exhaust are strikingly different from pure impingement and pure through drying rate curves, with the through flow water removal rate curve having at times a unique, secondary increasing rate period. Total drying rate is enhanced substantially by removal of a small fraction of the drying air as through flow exhaust.
Sequential design including initial experimental runs for a kinetic study of propylene oxidation
Authors: Akiti T. T. , Bircumshaw Jr. L. D. , Eckert R. E.
Published: March 2009

A sequential design strategy for selecting experimental runs to obtain model discrimination and precise parameter estimation is tested via a simulation study of propylene oxidation kinetics. The strategy is used to design all runs including the preliminary ones which were arbitrarily chosen by earlier researchers. To design initial runs, crude initial parameter guesses may be used in the rival models until least squares estimates can be calculated. Even under conditions of very bad initial guesses and high error variances, this procedure selects whichever model is the correct one and estimates with precision its parameters, in fewer runs than previously reported.
Optimum Multiple CFSTRs for a two stage fermentation of recombinant bacteria with a sensitive switching gene
Authors: Baheri H. R. , Hill G. A. , Roesler W. J.
Published: March 2009

The effect of increasing the number of CFSTRs either in a growth stage or production stage of a two step fermentation of a recombinant bacterium with an environmentally regulated gene has been investigated. The performance of the multiple CFSTR fermentation at its optimum design is compared to an optimum two stage fermentation. The results show that increasing the number of CFSTRs in the growth stage does not have any effect on the performance of the system, while increasing the number of CFSTRs in the production stage increases the productivity. The increase in the productivity, however, is small compared to the increase in the productivity that occurs with primary products, as reported in the literature. It is also shown that the results can be extended to other recombinant bacteria fermentations.
Modeling cat cracker catalyst demetallization
Authors: Kesavan Padmanaban , Law Victor J.
Published: March 2009

Vanadium and nickel have been identified as the major poisons that lead to the deactivation of cracking catalysts. These metals can be demetallized by a multistage process involving gas solid non‐catalytic reactions in porous particles. Mathematical models for predicting the removal rate of vanadium when diffusion, reaction, and reaction and diffusion are controlling have been developed. It is generally accepted that vanadium is deposited on specific sites in the interior of the catalyst. This is verified since a diffusion controlled model for the removal of vanadium is in close agreement with experimental results. The parameters of the diffusion controlled model were estimated by constrained nonlinear regression. A total of five lumped mass transfer parameters for vanadium removal were determined using data from a laboratory demetallization unit. These parameters were then used to predict vanadium removal and compared with experiment.
Removal of cadmium from wastewater by enhanced ultrafiltration using surfactants
Authors: Azoug C. , Sadaoui Z. , Charbit F. , Charbit G.
Published: March 2009

In order to recover cadmium ion from wastewater, a process based on enhanced ultrafiltration was finalised. The originality of the solution here proposed lies on the coupled use of ceramic membranes and of a surfactant added to the water to be treated. This paper deals with the study of the influence of experimental conditions upon permeation flux and selectivity of the separation. The process is efficient and flexible since a single stage treatment allows to reduce the concentration of cadmium in the effluent by a factor of about 750; this high performance in selectivity is on a par with high fluxes of permeate (roughly 170 L.h.−1.m−2 at 25°C and 3 × 105 Pa).
Hydrodynamic and mass transfer performance of multiple upcomer extraction trays
Authors: Zhu S. L. , Luo G. S.
Published: March 2009

The multiple upcomer (MU) extraction tray was specifically developed for aromatics extraction processes. Hydro‐dynamic and mass transfer experiments have been carried out with n‐butanol/succinic acid/water as an experimental system in a MU tray extraction column of 0.1 m diameter. The dispersed phase hold‐up, drop size and overall efficiency were measured and the hydrodynamic and mass transfer parameters were correlated. The flooding velocities and the overall efficiency predicted from the correlation for this column agreed well with the experimental data.
Balancing disinfection efficiency and THM formation during chlorination: Theoretical considerations
Authors: Chiang Pen‐Chi , Ko Ya‐Wen , Chang E. E. , Lou Jie‐Chung
Published: March 2009

A mathematical model has been developed to predict disinfection efficiency and trihalomethane (THM) formation during water chlorination. The model incorporates chlorine dose, total organic carbon (TOC) concentration, contact time, and geometric configuration of the chlorination chamber. Results indicate that the disinfection efficiency can be better controlled by modifying the geometric configuration of the chlorine contactor. In contrast, geometric configuration plays an insignificant role in controlling THM formation. The application of chlorine at about 1.0 mg/L appears to be the most economic and logical dose for the control of THM formation and the disinfection efficiency of the Liu‐Du water treatment plant under the operational conditions of conventional chlorination practices.
Reformulation of solid propellants and high explosives: An environmentally benign means of demilitarizing explosive ordnance
Authors: Wulfman David S. , Sitton Oliver , Nixon F. Terry , Podzimek Myroslava , Worsey Gillian , Beistel Donald , Worsey Paul , Burch Dan , Johnson Mike
Published: March 2009

Polymer Bound Explosives (PBXs) and Class 1.1 Military Propellants have been reformulated for use in the mining industry. There is a minimal waste stream. The explosives are sensitive to initiation by a #8 cap. Impact sensitivities have routinely passed 5 kg meter stimuli, initiation by 50,000 V AC and the BAM friction protocols at 1000 rpm under a 11 kg load for 10 seconds. The explosives were packed into sticks, slurried or used as pourable mixes. VoDs of 2.4 to 6.2 km/s were realized with τ = 0.9 — 1.35 t/m3. The explosives have powers comparable to a range of dynamites. The Beaver Code based upon Lotus 1.2.3 —gTM was developed to predict explosive properties.
Design of a continuous process for the alkaline treatment of xylose into lactic acid
Authors: Raharja S , Rigal L. , Barre L. , Vidal P. F.
Published: March 2009

A compact process based on a gas/liquid contactor was designed for the continuous alkaline oxidation of xylose into lactic acid. An experimental design using Doehlert's method was used to study the effect of: i) the NaOH concentration, ii) the xylose concentration, iii) the reaction temperature, and iv) the residence time, on the yield of lactic acid. Results indicate that the conversion of xylose at concentrations between 5‐15% (w/w) is complete and nearly instantaneous at both high temperatures (over 200°C) and high sodium hydroxide concentrations ((> 10% w/w). Yields of lactic acid reaching 50% (with a theoretical yield of 60% (w/w)) were obtained under the most favorable experimental condition suggested by the model developed.
Economic criteria in the design of cascades of CSTR's for the performance of enzyme‐catalyzed reactions
Authors: Malcata F. Xavier
Published: March 2009

The mass balances on substrate in each unit of a series of CSTRs performing an enzyme‐catalyzed reaction described by Michaelis‐Menten kinetics (with parameter Km) are written and the necessary and sufficient condition that must besatisfied by the intermediate concentrations in order to obtain a minimum overall capital investment is found on the assumption that the cost of each reactor unit scales up on its capacity according to a fractional factor exponential rule (with parameter n). The asymptotic situations of pseudo‐zero order and pseudo‐first order behavior are explored. The ratio between consecutive concentrations leading to a minimum overall capital investment decreases as Km decreases at a rate that is slower for higher n, and tends to unity as the pseudo‐first order situation is approached. If fractional values of n are considered, local minima of the capital investment associated with the overall reactor cascade exist only in certain ranges of substrate conversion; below the lower limits of such ranges, the number of reactor units should actually be decreased. A graphical procedure aimed at obtaining the intermediate optimal concentrations is presented.
Evaluation and characterization of vector fluids and peroxides in a process of in situ compatibilization of polyethylene and polystyrene
Authors: Sun Yi‐Jun , Flars Vicki , Baker Warren E.
Published: March 2009

An organic functional silane was found to be the most efficient among several vector fluids in reactive blend compatibilization of the polyethylene (PE) / polystyrene (PS) / peroxide / vector fluid system. This paper involves further analysis of this reactive blending system. Surface tension data was used to calculate spreading coefficients which were compared to the amount of PE‐PS copolymer formed during blending. A good correlation between a computed spreading coefficient and the degree of grafting of PS onto PE was found. The results suggest that the pattern of distribution of the vector fluid in PE / PS blends is the key factor leading to effective results. Furthermore, different peroxides were evaluated in PE / PS blends, in order to determine the dependence of PE / PS interfacial grafting reaction on the structure of the peroxide.
A new correlation for characteristic velocity in rotating disc contactors
Authors: Kalaichelvi Ponnusamy , Murugesan Thanapalan
Published: March 2009

On the basis of present experimental results along with those of available literature (1539 experimental results for 12 systems from 13 different sources) with a wide range of variables, a general correlation for the prediction of characteristic velocity, involving phase flow rates, rotor speed (in terms of Froude number), column geometry and also the physical properties, is presented. The present proposed correlations are more accurate than those previously reported.
Minimum spouting velocity for binary mixture of particles in rectangular spouted beds
Authors: Anabtawi M. Z.
Published: March 2009

Minimum spouting velocity data are reported for seven mixtures of polystyrene, spouted with air in three rectangular spouted beds of square cross sectional areas, using nozzles of five sizes. Correlations for minimum spouting velocity in cylindrical columns were investigated for this geometry. A new dimensionless correlation for predicting the minimum spouting velocity is developed.
Nonlinear instabilities of falling films on a heated vertical plane with gas absorption
Authors: Peramanu Subodhsen , Sharma Ashutosh
Published: March 2009

The nonlinear instability and dynamics of nonisothermal falling films with simultaneous absorption from a gas phase are studied theoretically. The study is based on a long wave analysis of equations of motion, energy and mass. The resulting long wave evolution equation describing the film thickness is solved by a Fourier collocation technique. The effects and interactions of flows resulting from gravity, surface tension, thermocapillarity and solutal Marangoni effect are elucidated by considering the following cases: (1) isothermal film; (2) nonisothermal film with purely conductive heat transfer, as well as combined conductive and convective heat transfer; and (3) nonisothermal film with solute absorption. Conditions are identified for equilibration of the wave, wave breaking and for the formation of dry spots. Also, phase diagrams representing the stable and unstable regions are presented for the above cases.
Solid—liquid mass transfer in a shaking vessel for a bioreactor with “current pole”
Authors: Kato Yoshihito , Hiraoka Setsuro , Tada Yutaka , Nomura Toshio
Published: March 2009

A shaking vessel with “current pole”, which is a center pole installed at the bottom, had shorter mixing time than a shaking vessel with a cone at the bottom. The mass transfer rate on the suspended particles was also measured in the shaking vessel where ion‐exchange resin beads were used as the suspended particles. The dependence of the solid‐liquid mass transfer coefficient on the circulating frequency changed at the critical circulating frequency for complete suspension NJS. For a circulating frequency higher than NJS, the mass transfer coefficient was correlated with the power consumption per unit volume, regardless of presence or not of the current pole.
Mixing study in an inductive plasma reactor: Comparison between model calculations and experimental results
Authors: Désilets Martin , Davies Benoît , Soucy Gervais , Proulx Pierre
Published: March 2009

This study compares the predictions of a multicomponent reactive model of inductive plasma reactor mixing and experimental data obtained with the enthalpy probe technique. Central injection of two different gases, helium and nitrogen, into the core of an inductive (h.f.) plasma discharge permits us to analyze the influence of the nature of the central gas on the reactor's mixing patterns. This work highlights diffusion in a multicomponent situation. The model considers the dissociation of H2, present in the sheath gas.
Modelling the boiling delay upon venting vapour from a saturated liquid—vapour system
Authors: Lubbe D. S. , Kornelius Gerrit
Published: March 2009

A mechanistic model was developed to describe the pressure history when vessels, containing initially saturated liquid, are subjected to sudden depressurisation. A governing equation based on a volume balance was set up. The terms in this equation governing the number of bubbles and the growth rate both before and after departure from the boiling surface are derived. Constants describing the boiling surface are required and derived from experimental work. The model results are compared to experiments at low (< 400 kPa) initial pressures, and reasonable agreement is obtained. The model results obtained for other parameters of practical importance (i.e. swell of the liquid phase and voidage) are shown.
Greffage de molécules à la surface du silicium par voie électrochimique
Authors: Ozanam François , Vieillard Charlotte , Warntjes Marcel , Dubois Thomas , Pauly Maxime , Chazalviel Jean‐Noël
Published: March 2009

La surface hydrogénée du silicium possède des propriétés remarquables, mais une stabilité à l'oxydation insuffisante. Pour y remédier, plusieurs groupes organiques ont été substitués à l'hydrogène de surface. Ces greffages peuvent se faire chimiquement en plusieurs étapes, mais la voie électrochimique permet des réactions directes à partir de la surface hydrogénée. On peut ainsi méthoxyler partiellement la surface du silicium poreux par dissolution anodique contrôlée, mais surtout méthyler sa surface de manière non destructive, avec un rendement de 80% limité seulement par l'encombrement stérique. La surface méthylée du silicium poreux possède une stabilité accrue d'un ordre de grandeur.
Mass transfer parameter estimation using optimization technique: Case study in CO2 absorption with chemical reaction
Authors: Ji Xinsheng , Kritpiphat Weerapong , Aboudheir Ahmed , Tontiwachwuthikul Paitoon
Published: March 2009

This paper proposes a new approach of applying an optimization technique to simultaneously determine a physical liquid—film mass transfer coefficient (KoL) and effective interfacial area (av) from a pilot plant data. The mass transfer mechanism of the CO2‐NaOH system was modeled using the two‐film theory to represent the behaviors of packed absorbers. The model presents an overall absorption rate (Rv) as a function of KoL and av. The optimization algorithm used in this study follows a modified Levenberg‐Marquardt method with a trust region approach. The Rv predictions from the model are in good agreement with the experimental data, with an average error of 6.5%.
Pressure drop prediction in hydraulic transport of bi‐dispersed particles of coal and copper ore in pipeline
Authors: Ghanta Kartik Chandra , Purohit N. K.
Published: March 2009

Hydraulic transport studies with coal and copper ore have been carried out in a 0.0254 m and a 0.019 m diameter pipeline to observe the effect of solids concentration, surface characteristics and particle size distribution on pressure drop. The coarse coal showed a lower pressure drop than the fines at any velocity of suspension, whereas copper ore, exhibited the opposite trend. It has been observed, that the pressure drop for hydraulic transportation of bi‐dispersed particles is a minimum at certain weight proportions of coarse to fines, as compared to that for the transportation of either of the single size.

Based on the experimental results, an empirical expression was developed for the prediction of pressure gradient.
Bubble formation in cocurrently upward flowing liquid
Authors: Terasaka Koichi , Tsuge Hideki , Matsue Hirokazu
Published: March 2009

The effects of liquid velocity, nozzle diameter, gas chamber volume and gas flow rate on volumes, shapes and growth curves of bubbles formed at a nozzle submerged in a cocurrently upward flowing liquid in a bubble column were experimentally investigated. The bubble volume decreases with increasing liquid flow velocity. The effect of liquid flow velocity on the volume of bubble increases with an increase in the gas flow rate. To simulate bubble formation at a nozzle submerged in cocurrently upward flowing liquid, a revised non‐spherical bubble formation model was proposed. Bubble volumes, bubble growth curves and shapes experimentally obtained in this study, as well as in previous experimental studies, are well predicted by the present model.
Hydrodynamic behavior of single particles in a draft‐tube bubble column
Authors: Kikuchi Ken‐Ichi , Takahashi Hiroshi , Sugawara Fumiya
Published: March 2009

Velocities of single particles (magnetic tracer particles) were measured in the draft tube region and annular region of a draft‐tube bubble columns by use of the magnet‐detector coil technique. The relative particle to liquid velocity was also obtained. The observed distribution of particle velocity was broader than that of liquid velocity. The relative particle to liquid velocity depended significantly on superficial gas velocity. Those for the draft tube region had minimums with increasing gas velocity, while those for the annular region decreased monotonously. The effective drag coefficients for the particles were correlated with particle Reynolds number and gas holdup.
Influence of particle‐specific gravity and particle shape on the averaged axial velocity of nearly neutrally buoyant particles in horizontal pipes
Authors: Liu S. , Fryer P. J. , Pain J. P.
Published: March 2009

This paper presents an experimental study on the velocities of single, nearly neutrally buoyant particles in water in horizontal flows. Particle specific gravity was found to have a strong effect on the particle velocity. The modified particle Froude number was found to be an effective parameter to reflect the effect of density. A force‐balance model has been developed that includes the effects of particle specific gravity and particle shape.
On a eulerian and lagrangian combined model in dense particle‐laden riser flow
Authors: Fan Jianren , Sun Ping , Ma Yinliang , Cen Kefa
Published: March 2009

A new numerical model using both Eulerian and Lagrangian coordinates, and taking account of interparticle interactions, has been developed for the study of hydrodynamic aspects of dense particle‐laden rise flows. A stochastic particle dispersion model has been incorporated in the original model to describe the gas particle turbulent flows. In addition, the collisional interaction between the particles has been modeled using the kinetic theory of granular flows based on the Chapman‐Enskog theory of dense gases. A comparison with the experimental results of Miller and Gidspow (1992) shows reasonably good agreement. The present model may provide a useful approach for predicting the complex hydrodynamic behaviour of fluidized bed systems.
Enlèvement du phosphore des eaux usées par traitement à base de tourbe dopée aux boues rouges
Authors: Roberge Guy , Blaies Jean‐François , Mercier Guy
Published: March 2009

L'ajout d'un agent dopant à base d'aluminium et de fer, soit les boues rouges issues de l'extraction de l'alumine de la bauxite, a été testé avec une tourbe horticole commerciale et ce, pour l'épuration d'eaux usées municipales provenant d'un traitement secondaire. Suite à des essais en colonnes, l'efficacité de déphosphatation est passée de 17 et 21% sur la tourbe uniquement à plus de 95% en présence de l'agent dopant. De même, l'utilisation de boues rouges a permis de réduire la concentration de Pt de l'effluent à moins de 0.15 mg/L. L'effet dopant diminuait avec le temps et surtout pro‐portionnellement à la charge hydraulique appliquée. Pour une charge de 30 cm/j j la déphosphatation respectait les recommandations gouvemementales (Pt, dans l'effluent <1 mg/L) et ce, pour une période de 50 jours. Les performances sur les autres paramètres indicateurs classiques tels la DBO5, le DCO et l'enlèvement des coliformes ne furent pas altérés par l'emploi de l'agent dopant.
The achievability of sustainable reporting practices in agriculture
Authors: Williams Belinda R. , Wilmshurst Trevor
Published: March 2009

This research investigates the process of change in moving from a domestic accounting standard, AASB 1037, relating to self‐generating and regenerating assets (SGARAs) to an international standard, AASB 141. It focuses on the achievement (or nonachievement as it may be) of sustainable reporting practices for these agricultural assets. This paper finds that the transition to AASB 141 has allowed firms the discretion to change how they value their agricultural assets in comparison to the domestic standard. Consistency may have been achieved to a limited extent with the introduction of this financial accounting standard but comparability appears not to have been. Further, there is very limited understanding of the reporting of these assets from a user's perspective. It is concluded that this lack of consistency, comparability and understandability will not help achieve sustainability in the reporting practices of agricultural assets. Copyright © 2009 John Wiley & Sons, Ltd and ERP Environment.
Quantitative changes in hippocampal microvasculature of chronically stressed rats: No effect of fluoxetine treatment
Authors: Czéh Boldizsár , Abumaria Nashat , Rygula Rafal , Fuchs Eberhard
Published: March 2009

Exposure to chronic stress alters the number and morphology of neurons and glia in the hippocampal formation; however, little is known about possible changes in vasculature. Here, we examined the effect of chronic social defeat stress on hippocampal vascular supply in rats. Recent reports document that antidepressant treatment can influence angiogenesis in the hippocampus; therefore, we also studied the effect of antidepressant drug treatment on hippocampal capillarization. Animals were subjected to 5 weeks of daily social defeat by an aggressive conspecific and received concomitant, daily, oral fluoxetine (10 mg/kg) treatment during the last 4 weeks. Rat endothelial cell antigen‐1 (RECA‐1)‐labeling of capillaries and quantitative stereological techniques were used to evaluate the treatment effects on capillary number. Special attention was paid to analysis of the vascular supply of the subgranular zone, which is regarded as an important component of the neurogenic niche for adult hippocampal neurogenesis. Chronic stress significantly decreased the number of microvessels by 30% in all hippocampal subregions, whereas fluoxetine treatment had no influence on capillary number. Furthermore, chronic stress decreased the capillarization of the subgranular zone to a similar extent, indicating that chronic stress affects the vascular niche for adult hippocampal neurogenesis. However, fluoxetine treatment had no impact on capillarization in the subgranular zone. We also detected a decrease in hippocampal volume in the animals as a result of stress, which was mildly altered by fluoxetine treatment. These pronounced changes in vascular supply may explain why the hippocampus is more vulnerable to insults when chronic stress precedes or coincides with other harmful conditions. Reduced microvasculature may also contribute to hippocampal volume decrease in stress‐related disorders. © 2009 Wiley‐Liss, Inc.
Automated explanation of financial data
Authors: Daniels H. A. M. , Caron E. A. M.
Published: March 2009

We describe a methodology for explanation generation in financial knowledge‐based systems. This offers the possibility to generate explanations and diagnostics automatically to support business decision tasks. The central goal is the identification of specific knowledge structures and reasoning methods required to construct computerized explanations from financial data and models. A multistep look‐ahead algorithm is proposed that deals with so‐called cancelling‐out effects, which are a common phenomenon in financial data sets. Our method is an extension of the traditional variance decomposition in accounting. The method was tested on a case‐study conducted for Statistics Netherlands involving the comparison of financial figures of firms in the Dutch retail branch. Copyright © 2009 John Wiley & Sons, Inc.
Die thermische wolff‐umlagerung der 1,2,3‐thiadiazole
Authors: Meier Herbert , Bühl Hanspeter
Published: April 2009

Thermal nitrogen elimination of 1,2,3‐thiadiazoles leads to primary fragments, which rearrange to thioketenes. In the presence of high boiling alcohols like diglycol, the corresponding esters can be isolated in good yields. Benzo‐1,2,3‐thiadiazole, which does not rearrange, is an exception, because of the integrity of the aromatic nucleus.