ISSN:0268-2575    

DOI:10.1002/jctb.280520102

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractFluid transport behaviour is of great importance within the chemical process industry and in biotechnology. The complexity of this behaviour, reflected in the nature of the fundamental partial differential equations which describe it analytically, means that it has to be treated by numerical methods.In this paper the basic equations are given, and the approaches necessary to treat laminar and turbulent flows are carefully explained. As digital computers have increased in size, so has the comprehensiveness of the problems which can be treated, and the development of typical computer programs is described.Problems of accuracy and experimental validation are also surveyed, and it is shown that recent developments in whole‐field optical measurement methods, and image and data processing are all involved here. Then, a review of work at City University is shown to comprise typical examples of applications to engineering situations and biotechnology problems. Chosen instances of the former are flow and heat transfer behaviour for convective enhancement caused by roughness elements, and the design balancing of a thermosyphon. The latter include such diverse studies as blood flows in arterial bifurcations, and heat and mass transport in grain storage. They involve the three‐dimensional and transient capabilities of current codes, and their applicability to non‐standard geome

ISSN:0268-2575    

DOI:10.1002/jctb.280520103

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractThe SGI Ultrafermenter is an external loop bioreactor with circulation through an ultrafiltration module allowing removal of medium and soluble products during fermentation. The contents are continually circulated during operation and the vessel is also equipped with a stirring turbine. The interaction of these two mixing agents on gas transfer was investigated. Both mechanisms produced similar increments in KLa over their working ranges, with values from approximately 0–700 h−1at 200 dm3h−1airflow. The effects of these two mechanisms on KLa were approximately additive at low values but the combined mixing produced a maximum KLa value also in the region of 700 h−1. The power‐draw of mixing using the two agents was calculated and stirring was found to be 10–20 times more efficient than

ISSN:0268-2575    

DOI:10.1002/jctb.280520104

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractAlcohol dehydrogenase (ADH) from horse liver (EC 1.1.1.1), cross‐linked through the bifunctional reactive glutaraldehyde, onto nylon tubing was immobilized (35 μg cm−2internal surface of nylon tubing). ADH inactivation kinetics of the immobilized enzyme are of first order (t1/2= 84.3 h, k = 5.2 × 10−3h−1at 5°C; t1/2= 2.6h, k = 0.26 h−1at 50°C). The activity versus pH profile points to a smaller effect of pH on the activity of the enzyme, which is the case of ADH in solution, explicable on the basis of limitations to proton diffusion towards/from the support. A limiting effect to free external diffusion of the substrate (products) towards/from the support was observed; this effect seems to determine the effective kinetic behaviour of im

ISSN:0268-2575    

DOI:10.1002/jctb.280520105

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractThe polarographic behaviour of some α‐arylhydrazono‐3‐ketimino‐nitriles (Ia—h) in 50% ethanolic aqueous buffer is reported and discussed. The mechanism of electrode processes corresponding to the observed cathodic waves is proposed and confirmed by the aid of model compounds as well as through identification of controlled potential electrolysis products. The E1/2and pKa values of the title compounds were evaluated and correlated to Hammett constants. The physical characteristics of the studied compounds in DMF regarding their redox potential (Δ1/2); electron affinity (EA); ionization potential (IP); electronic transition energy (ECT) and coulomb repulsion integral (J12) were computed. A linear correlation was shown to exist between

ISSN:0268-2575    

DOI:10.1002/jctb.280520106

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractThe continuous chromatographic separation of inverted beet molasses resulting in a fructose rich product and a product containing glucose and other non‐sugars was carried out using a semi‐continuous countercurrent chromatographic refiner (SCCR6), consisting of ten 10.8 cm diameter by 75 cm long stainless steel columns packed with a calcium charged 8% cross‐linked polystyrene resin, zerolit SRC14.It was found that cations present in beet molasses displaced calcium ions from the resin resulting in poor separation of the glucose and fructose. Three methods of maintaining the calcium form of the resin during the continuous operation of the equipment were established. Passing a solution of calcium nitrate through the purge column for half a switch period was found to be most effective as there was no contamination of the main fructose rich product and the product concentrations were increased b

ISSN:0268-2575    

DOI:10.1002/jctb.280520107

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractBiosorption of heavy metals by microbial cells has been recognized as a potential alternative to existing technologies for removing heavy metals from industrial waste waters. Many aquatic microorganisms, such as algae, can take up dissolved metals from their surroundings to their cells. In this study, the adsorption of lead(II) ions was investigated in a single‐staged batch reactor. Chlorella vulgaris, a green alga, was used as the sorbent. The sorption phenomenon was expressed by the Freundlich adsorption isotherm and this expression was used for the calculation of residual or adsorbed metal ion concentration at equilibrium (Ceqor Cx,eq) at a given ‘volume of waste water containing heavy metal ion/quantity of alga (V0/X0)’ ratio in a single‐staged batch reactor. Experimental Ceqand Cx,eqvalues were compared to calculated ones. Applications in waste water treatment for lead(II) removal have been su

ISSN:0268-2575    

DOI:10.1002/jctb.280520108

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractProcess of rhenium removal from acidic industrial effluents by pressure reduction with gaseous hydrogen and sulphur dioxide was examined. Solutions from two sources were investigated, namely: circulating wash liquors originated from a wet dedusting of converter gases, and from dedusting of Dörschel furnace gases at a copper smelter. The effects of temperature, sulphuric acid concentration, and addition of an activated charcoal carrier were determined on rhenium recovery. Complete removal of rhenium from the solution has been achieved with both hydrogen and sulphur dioxide and the concentration of rhenium in the resultant concentrate reached 3%. The technological process for recovering rhenium from acidic industrial effluents was suggested

ISSN:0268-2575    

DOI:10.1002/jctb.280520109

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractContinuous alcoholic fermentation of untreated crude sugar beet molasses has been studied. The process was carried out in a vertical fluidized‐bed reactor with beads of calcium‐alginate containing immobilizedSaccharomyces cerevisiae. The influence of hydraulic residence time, concentration of substrate and other variables have been stud

ISSN:0268-2575    

DOI:10.1002/jctb.280520110

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY

摘要:

AbstractAmmonia inhibition of unacclimated anaerobic mesophilic mixed cultures was studied in batch mode. Bacterial growth rate and specific acetate‐uptake rate were affected by the concentration of un‐ionised ammonia (UAN) in a three‐stage pattern: initial inhibition, plateau and final inhibition stage. The un‐competitive inhibition model provided the most reasonable data fit. The stage pattern of inhibition suggested that more than one mechanism of UAN inhibition are acting on the mixed culture. The effects of UAN on the length of initial lag‐time also followed a three‐staged curve. High concentration of UAN resulted in acetate release. The biological basis and origin of the acetate release were not

ISSN:0268-2575    

DOI:10.1002/jctb.280520111

出版商:John Wiley&Sons, Ltd.    

年代:1991

数据来源: WILEY