bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of hydrous titania from titanous chloride. III: Thermal studies (B) and surface texture
Authors: Ragai Jehane
Published: July 2010

The present investigation deals with the surface properties of titania gels prepared from titanous chloride and ammonium carbonate under acidic and alkaline conditions of pH. The dehydration characteristics of such hydrous oxides are also investigated by means of simultaneous differential thermal analysis, thermogravimetric analysis and differential thermogravimetric analysis. Contrary to hydroxide‐precipitated gels, even at a low pH of precipitation, very little ‘coordinated’ water remains in these gels.

It is suggested that it is the concomitant presence of ammonium and carbonate ions in the precipitating agent, acting together, that provide the conditions favorable for the development of microporosity and high surface area in the gels.
Application of powder coatings: Viscosity and density measurements in a conventional fluidized bed
Authors: Damia Augusto J. , Caprari Juan J.
Published: July 2010

The values of dynamic viscosity characteristic of the different stages in a fluidized bed were determined using a torsional viscometer (Dragge Eppretch Rheometer type STVK) with a specially designed cup. Experiments were made with three kinds of rotor: a full paddle, a cylinder and a split paddle.

Apparent densities have been determined by measuring differential pressures across known heights in an experimental fluidized bed. A modified Matheson equation has been developed to determine the values of maximum bed density and minimum bed porosity, associated with the inset of fluidization.

The experimental determinations were made with a white powder coating in which the granulometric distribution and composition were previously established.
A kinetic model for pretreated wheat straw saccharification by cellulase
Authors: Gonzàlez Gloria , Caminal Gloria , De Mas Carles , Lopez‐Santín Josep
Published: July 2010

A kinetic model for enzymatic hydrolysis of pretreated wheat straw able to describe the reaction process considering only macroscopic properties of enzyme and substrate would be useful in reactor design and scale‐up. In this study Michaelis‐Menten equations were used for different reaction schemes to fit experimental results obtained, working with enzyme loads between 5 and 44 i.u. g−1 pretreated straw. Kinetic parameters were obtained by means of an optimization computer program.
Anaerobic digestion of seaweed for biogas: A kinetic evaluation
Authors: Anjaneyulu K. , Tarwadi S. J. , Mehta D. J.
Published: July 2010

A kinetic study of biogas production in batch digesters by anaerobic digestion of seaweed, Sargassum tenerrimum, with a mixed bacterial culture consisting of methanogenic bacteria and an algin‐degrading bacterial strain was carried out at different concentrations of dry total solids. Specific rate constants of biogas production during the lag, exponential and monomolecular (stationary) phases of bacterial growth were determined. About half the total volume of biogas was generated during the exponential phase irrespective of the concentration of seaweed in the digesters. The specific rates of substrate destruction and biogas generation in the stationary phase decreased with increasing substrate concentration. The yield of biogas per gram dry total solids of seaweed was about the same at all concentrations, but with a marked decline at 12% (w/v) total solids. The maximum destruction of volatile solids effected was about 63% over a period of 72 days.
Overview of the pulp and paper industry from a chemical industry perspective
Authors: Smook Gary A.
Published: July 2010

The major processes of the pulp and paper industry are overviewed with particular emphasis given to existing chemical requirements; processing trends are identified which may affect future chemical requirements. The pulp and paper industry represents a vast market for chemicals. On the papermaking side, overall chemical usage will probably increase due to ever greater product sophistication and emphasis on value‐added grades. On the pulping side, the pressing needs for fibre conservation and more effective utilization of fibre sources can only be achieved through continuing exploitation of chemical developments.
Effect of plasticizer on the physicochemical properties of vinyl coatings submerged in artificial seawater
Authors: Di Sarli A. R. , Schwiderke E. E. , Podestá J. J.
Published: July 2010

The effect that type and content of plasticizer has on several physicochemical properties of vinyl varnishes was studied.

A vinyl resin (VAGD) plasticized with di‐isodecyl phthalate (DIDP) or tricresyl phosphate (TP) in 2:1, 4:1, 6:1 and 10:1 resin:plasticizer ratios was employed. Naval steel plates were coated with the different formulations and submerged in artificial seawater.

The coefficients of diffusion, solubility and permeability to water were calculated, measuring the impedance vector evolution during the first 15 min of immersion. Corrosion potential measurements as well as the ionic resistance (Rm) and dielectric capacitance (Cm) were carried out for 40 days.

The results obtained make it possible to infer that, independently of the type of plasticizer employed in the formulation, the increase of the resin:plasticizer ratio produces a decrease of water permeability. This effect is associated with more positive corrosion potentials, higher ionic resistances and lower dielectric capacitances. Besides, for equal resin:plasticizer ratios, the samples plasticized with DIDP showed, in general, lower permeability than those plasticized with TP.

Finally, the high barrier effect corresponding to samples with 6:1 and 10:1 resin:plasticizer ratios is very important since decreasing solvent content also decreases solvent retention in the film and consequently its adverse effects on the protective properties of the coating.
Dynamic measurement of KLa with oxygen‐enriched air during fermentation
Authors: Kim Dong‐Jin , Chang Ho‐Nam
Published: July 2010

A method of KLa estimation, utilising gassing with oxygen‐enriched air, was applied to fermentations of Escherichia coli and Saccharomycopsis lipolytica. The method consists of sudden inlet oxygen concentration increase while total inlet gas flow rate is held constant. Dissolved oxygen concentrations are measured by an oxygen electrode, the response of which is assumed to be first order. KLa can be estimated from the slope of the semilogarithmic plot of the electrode response versus time. The method seems to be valid as long as the dissolved oxygen concentration is higher than the critical oxygen concentration below which oxygen uptake rate is dependent on dissolved oxygen concentration.
Resins for high‐purity water production
Authors: Ball M. , Harries R. R.
Published: July 2010

In plants for the production of feedwater for high‐pressure boilers, it is important to specify appropriate parameters for the ion exchange resins used. The parameters proposed for all make‐up plant resins are total exchange capacity, bead integrity and physical strength (resistance to osmotic shock and attrition), supplemented by maximum, minimum and harmonic mean bead sizes appropriate for use in cation exchange, anion exchange and mixed bed units.

For condensate purification plant resins, total exchange capacity, bead integrity, physical strength and bead size are again specified, with tighter limits for resistance to osmotic shock and attrition, to reduce the risk of physical breakdown in service. Bead densities should be included and closer bead size distributions to ensure good overall kinetics for cation and anion exchange, whilst maintaining good separation on backwashing. A minimum mass transfer coefficient is also required to ensure adequate anion exchange kinetics for sulphate at the typical condensate purification plant linear flow rate of 100m/h. Consideration should be given to specifying the maximum organic matter that may be released by new resins in contact with water in an endeavour to limit the amount of deleterious chemical compounds produced in manufacture that can be released into the treated water.
Vernolic and cyclopropenoid fatty acids in Plectranthus mollis, syn. Plectranthus incanus, link seed oil: A rich source of oil
Authors: Mahmood Chirag , Daulatabad Jehan D. , Mirajkar Abdurrazzaque M.
Published: July 2010

Plectranthus mollis, syn. Plectranthus incanus Link seed oil contains the following acids: palmitic (7.2%), stearic (13.6%), oleic (21.7%), linoleic (46.5%), malvalic (2.3%), sterculic (3.2), and vernolic (6.1%).
Landfill co‐disposal: Hydraulic loading rate considerations
Authors: Watson‐Craik Irene A. , Senior Eric
Published: July 2010

Single‐stage laboratory models, with liquid recycle, were used to examine the attenuation of phenol (2 mmol dm−3) in domestic refuse. High hydraulic loading rates (≥37.3 cm3 h−1) maximised phenol attenuation rates although, with lower loading rates (20.9 cm3 h−1), residual substrate concentrations remained low. With successive reservoir supplementations, these patterns were repeated although for each loading rate the maximum phenol concentration attenuated by each column passage increased. A semilogarithmic plot of hydraulic load against filter efficiency approximated to a straight line and thus indicated that further increases in hydraulic loading rates would not facilitate significantly improved total phenol removals.
Factors affecting biosurfactant production using Pseudomonas aeruginosa CFTR‐6 under submerged conditions
Authors: Ramana K. Venkata , Karanth N. G.
Published: July 2010

Studies on the biosurfactants produced by Pseudomonas aeruginosa CFTR‐6 revealed that they consisted of glycolipids R‐1 and R‐2. A time course study of fermentation indicated that the appearance of glycolipids in the fermentation broth coincided with the exhaustion of nitrogen and the commencement of the stationary phase with respect to biomass. The effect of variation of the media components such as carbon, nitrogen, phosphate and metal ions has been investigated. The following values were found to be optimum for biosurfactant production: glucose, 20 g dm−3; carbon to nitrogen ratio, 38; phosphate, 30 mmol dm−3; MgSO4.7H2O, 100 mg dm−3. Addition of iron to the medium significantly diminished the glycolipid yield.
Effects of oxygen diffusion on recombinant E. coli B (pTG201) plasmid stability, growth rate, biomass production, and enzyme activity in immobilized and free bacteria during continuous culture
Authors: Huang Jun , Dhulster Pascal , Barbotin Jean‐Noël , Thomas Daniel
Published: July 2010

The influence of oxygen diffusion on kinetic properties, plasmid instability, biomass production and enzyme production of recombinant Escherichia coli B containing plasmid pTG201 was investigated. The experiments were carried out using continuous cultures and two types of medium, with immobilized bacteria in carrageenan gel and free bacteria. The specific growth rate of immobilized bacteria was a monotonic function of dissolved oxygen (DO) level from 0% DO to 100% DO, and it increased 63% in L‐Broth medium and 70% in minimal medium with respect to 0% DO, but the growth rate was quickly reduced above 75% DO (L‐Broth medium) or 50% DO (minimal medium) in free bacteria. The specific growth rate was generally higher for free bacteria than for immobilized bacteria. The plasmid was substantially more stable at 0% than at 50% or 100% DO in both immobilized and free bacteria. Biomass production was proportional to the growth rate, and this in turn was greatly influenced by the DO concentration. Measurements of enzyme production showed that the enzyme activity was diminished in both immobilized and free bacteria when oxygen was eliminated. The observed increase in plasmid stability may have resulted from the disturbance of low growth rate and decreased expression of the enzyme.
Influence of the contact model and support characteristics on the partition constant for kinetically controlled synthesis of peptides
Authors: Clapés Pere , Mata‐Alvarez Joan , Valencia Gregorio , Reig Francesca , Haro Isabel , García‐Antón José‐María
Published: July 2010

The influence of the physical characteristics of the support and the contact model on the partition constant (p) in kinetically controlled peptide synthesis was studied. Large values for p were obtained using a small pore size carrier and a recirculation reactor. However, with a larger pore size carrier and the same contact model, p values were lower, the latter conditions were more favorable for product synthesis.
Equilibrium adsorption isotherms for basic dyes onto lignite
Authors: Allen Stephen J. , McKay Gordon , Khader K. Y. H.
Published: July 2010

The adsorption of two basic dyes in aqueous solutions onto lignite is reported. The adsorption equilibrium isotherms are recorded for the dyes in single component solution. The isotherms are plotted to obtain the Freundlich constants, the Langmuir constants, and the Redlich‐Peterson constants.
Formation of submillimeter liquid‐encapsulated gas bubbles in an immiscible liquid
Authors: Mori Yasuhiko H. , Kogo Yasuyuki , Kaminaga Keiji
Published: July 2010

A simple device is described which enables a steady formation of small ‘two‐phase bubbles’ each consisting of a core of a gas and a shell of a liquid which is immiscible with the surrounding liquid. The device is essentially a fine double‐tube nozzle which permits parallel feedings of the gas and the liquid to its tip having a particular configuration. It has been found that the device successfully releases into a pool of pure water, liquid‐fluorocarbonencapsulated bubbles of uniform diameter of less than 1 mm. The function of the device is lost, however, when the water is contaminated with surfactants. The device may be applicable to some extraction processes whose efficiency should be increased by producing small liquid‐encapsulated bubbles.
Removal and recovery of uranium by modified Pinus radiata D. Don bark
Authors: Freer Juanita , Baeza Jaime , Maturana Hernán , Palma Graciela , Durán Nelson
Published: July 2010

Bark from Pinus radiata D. Don was treated with both sulfuric acid/formaldehyde and nitric acid/formaldehyde. The ability to adsorb uranium by the bark was improved by these treatments, with essentially zero bleed colour into solution. The resin produced by nitric acid/formaldehyde treatment showed, in general, a better retention capacity than that of sulfuric acid/formaldehyde treatment. The nitric acid/formaldehyde modified bark showed 96 % of adsorption of uranium after 1 h and 63 % of desorption from the loaded resin after 3 h in 0.5 M sulfuric acid solution. Unmodified bark and some bark components were also analyzed. Bark was shown to be an excellent adsorber, comparable in efficiency, but costing less than the commercial adsorbing agents.
Purification and characterization of cellulases from Clostridium papyrosolvens
Authors: Garcia Vicenta , Madarro Alejo , Peña Jose L. , Piñaga Francisco , Vallès Salvador , Flors Agusti
Published: July 2010

The extracellular cellulolytic enzyme complex from Clostridium papyrosolvens was isolated from a culture of this organism grown on filter paper. The complex showed xylanase, carboxymethyl cellulase (CMCase) and Avicelase (but not β‐glucosidase) activities. Non‐denaturing polyacrylamide gel electrophoresis (PAGE) revealed two dominant bands, sited at the origin (corresponding to a fraction of high molecular weight) and at 280 kDa, and eight other very weak bands in the 20–180 kDa MW range. Gel overlay techniques showed strong CMCase activity in the region comprised between the origin and 320 kDa and in three distinct sites in the 40–230 kDa region. Xylanase activities were detected as a continuous band almost covering all the track. SDS—PAGE gave a multiplicity of different intensity bands in the 20–130 kDa range. Cellulolytic activities (CMCase in the 85–90 kDa range) and hemicellulolytic activities (xylanase at approximately 95, 60, 42 and 32 kDa) were detected through application of the corresponding CMC and xylan overlay techniques. Though anion‐exchange chromatography (DEAE‐Sephadex A‐50) and gel filtration (Biogel P‐100) techniques did not permit a good separation of the different cellulolytic activities, an 11.3‐fold increase of the Avicelase specific activity was achieved in a fraction containing 38.5% of the original total activity. Maximum enzymatic activities in crude preparations were observed at pH 5.4 and 50°C for xylanase and at pH 4.8 and 45°C for CMCase. The Michaelis constants for CMCase and xylanase were respectively: Vmax = 9.1 μg glucose equivalents min− ml−, Km=3.3 g CMcellulose liter− and Vmax=44.5 μg xylose equiuulents min− ml− and Km=2.7 g xylun liter−. Both enzymes were inhibited by a competitive mechanism.
Anaerobic filters for municipal wastewater treatment
Authors: Viraraghavan T. , Landine R. C. , Pyke S. R.
Published: July 2010

Four laboratory reactors (two downflow rock, one downflow wood, and one horizontal flow rock) were operated at 35–38°C for an initial period of six months and later at 23‐27°C, with primary clarifier effluent (PCE) from a municipal wastewater treatment plant as the feed to the reactors. A pilot‐scale rock medium reactor located at a municipal wastewater treatment plant was operated at 24–28°C initially in the downflow mode and later at 18‐20°C in the upflow mode with PCE as feed. The laboratory study showed that PCE can be successfully treated using both downflow and horizontal flow anaerobic filters, with similar performance under both flow modes.

Bench‐scale filters obtained better BOD and SS removals compared to the pilot‐scale filter.
Substrate sequestration and product inhibition in enzymic reactors: Analytical model and experimental studies
Authors: Raul Avrom Z. , Ilan Ehud , Lotan Noah
Published: July 2010

The adverse influence that substrate sequestration exerts on the performance of a continuously operated, plug‐flow enzymic reactor was studied both experimentally and theoretically. Thus, glutathione‐S‐transferase was immobilized on activated agarose, and its performance in a packed‐bed reactor, both in the presence and in the absence of bovine serum albumin as sequestrator, was investigated. In parallel, an analytical model was developed, accounting for the behavior of systems which obey Michaelis—Menten kinetics, and which involve substrate sequestration and product inhibition. Substrate conversion in the reactor was found to decrease as sequestrator concentration and/or substrate—sequestrator association constant increased.
The use of vegetable oils to recover compounds from aqueous solutions
Authors: Welsh Frank W. , Williams Ross E.
Published: July 2010

Corn oil, canola oil, olive oil, sunflower oil, peanut oil and soyabean oil were tested as extractants for the recovery of organic compounds from aqueous solution. Short chain aliphatic alcohols and acids were poorly recovered (Kd < 1.0) while most esters, aldehydes and aromatic compounds tested were satisfactorily recovered (Kd > 2.0) from aqueous solution by vegetable oils. Kd is defined as the ratio of the concentration of the dissolved substance in the extractant to that in the aqueous phase. The exception was caffeine which was poorly extracted from water. The type of oil used appeared to have limited effect on Kd. Increasing the reaction temperature resulted in increased Kd for most readily extractable compounds. Acidulated fatty acid was also tested as an extractant. Although it generally resulted in a greater Kd than the oils or hexane control, acidulated fatty acid was less desirable as an extractant because it tended to create an emulsion with the aqueous phase under the test conditions.
The effect of lauric acid shock loads on the biological and physical performance of granular sludge in UASB reactors digesting acetate
Authors: Rinzema Arjen , Alphenaar Arne , Lettinga Gatze
Published: July 2010

The specific activity of acetotrophic methanogens and the physical behaviour of granular sludge in laboratory‐scale upflow anaerobic sludge bed (UASB) reactors subjected to shock loads of lauric acid in the absence and presence of calcium were studied. In the absence of calcium, lauric acid completely inhibited acetotrophic methanogens above a threshold level of 100 mg C12:0dm−3, whereas no inhibition occurred below this threshold concentration. Addition of an equivalent amount of calcium to wastewater containing lauric acid prevented inhibition of acetotrophic methanogens at least up to 1500 mg C12:0dm−3. Addition of less than an equivalent amount of calcium apparently removed more than a stoichiometric amount of lauric acid: 50 % inhibition occurred at approximately 700 mg ‘free’ or excess C12:0dm−3. The results indicate that complete sludge wash‐out from conventional UASB reactors is likely to occur within 2‐8 h if the system is overloaded with an influent containing more than 100 mg C12:0dm−3. Calcium did not prevent wash‐out.
Inequivalent quadrupolar couplings of the deuterium‐exchanged nitrogen in micellar liquid crystals
Authors: Huque Entazul M.
Published: July 2010

In deuterium NMR, two inequivalent quadrupolar couplings of the deuterium‐exchanged nitrogen in a hydrocarbon chain near a chiral carbon atom have been observed in the nematic and cholesteric mesophases. The two quadrupolar doublets arise from the ND segments of the amphiphile and are interpreted as being due to the intramolecular motion in the amphiphile chain about the C—N bond. Different peak intensity of the two doublets suggests that one conformation is more stable than the other.
Study of cyclodextrin production using cyclodextrin glycosyltransferase immobilized on chitosan
Authors: Yang Chin‐Ping , Su Chein‐Shyong
Published: July 2010

Cyclodextrin glycosyltransferase (CGTase EC.3.2.1.19) was immobilized on chitosan through covalent bonding using glutaratdehyde. Various characteristics of immobilized CGTase (ICGTase) such as the pH—activity curve, the temperature—activity curve, pH and thermal stability, batch re‐usability and continuous operation stability were evaluated. Among them, the pH optimum and temperature optimum of CGTase were shifted from pH 7.5 and 55°C to pH 8.5 and 60°C after immobilization. No increase of pH stability was observed, whereas the thermal stability of ICGTase was superior to that of free CGTase. ICGTase retained 83 % of relative activity in converting liquefied starch (5% (w/v)) to cyclodextrins (CDs) under the conditions of four times of repeated use of 23 h conversion by the batch system at 55°C and pH 8.5. The half‐life of ICGTase under the same conditions by the continuous operation system was about 6 days. About 46 % of the liquefied potato starch solution (5 % (w/v)) was converted to CDs by ICGTase. Addition of ethanol in starch solution was found to increase the formation of β‐CD, and 58‐3 % yield of CDs was obtained by the addition of 16 % (v/v) ethanol in starch. The kinetic constants Km and Vmax of ICGTase and free CGTase were also examined.
Kinetics of hydrogenation of D‐glucose to sorbitol
Authors: Verma Rohit , Gehlawat Jagdish K.
Published: July 2010

The kinetics of the heterogeneous reaction between hydrogen and aqueous solutions of D‐glucose to produce sorbitol were studied in a high pressure Parr reactor. Raney‐Ni was used as catalyst. The reaction between hydrogen and D‐glucose was found to be very slow. In the agitated slurry reactor the diffusional aspects were completely eliminated and the reaction followed homogeneous kinetics. It was found to be first order with respect to both hydrogen and D‐glucose. The values of the pseudo‐first‐order rate constants were found to be 1.5 × 10−4 and 6.4 × 10−4s−1 at 398 and 435 K, respectively. The activation energy was found to be 64.8 kJ mol−1.
Continuous simultaneous saccharification and fermentation of raw starch in a membrane reactor
Authors: Matsumura Masatoshi , Hirata June
Published: July 2010

A kinetic model for simultaneous saccharification and fermentation (SSF) of raw starch is proposed. The model includes the effect of ethanol on an active site for saccharification and the decay of a raw starch affinity site. The kinetic parameters were determined by using the experimental results of a batch saccharification and a long‐term repeated‐batch SSF of raw sweet potato starch. From analysis of the experimental results it is concluded that two subsites took part in ethanol inhibition, and that the inactivation of the raw starch affinity site was induced by adsorption of glucoamylase onto raw starch. The proposed kinetic model successfully predicted the progress of continuous SSF in a membrane reactor.
Determination of starch and maltose using immobilized amyloglucosidase and a glucose electrode in a flow injection system
Authors: Gorton Lo , Appelqvist Roger , Johansson Gillis , Scheller Frieder , Kirstein Dieter
Published: July 2010

Maltose and starch were hydrolysed to glucose by immobilized amyloglucosidase in a packed‐bed reactor and then measured by a glucose oxidase electrode in a flow injection analysis manifold. The steady‐state signals for both maltose and starch were constant for reactor residence times between 24 and 73 s. They were reduced on addition of mutarotase by c. 10 % with maltose and by c. 20 % with starch. The steady‐state value for glucose in the presence of mutarotase coincided with that for equivalent amounts of both maltose and starch according to Zulkowski, indicating a 100 % conversion im the amyloglucosidase reactor. For 40‐μm3 samples, linear response curves were obtained over 100‐fold range of concentration. The maximum injection rate corresponded to 30 samples h−1.
Recovery of biosurfactants by ultrafiltration
Authors: Mulligan Catherine N. , Gibbs Bernard F.
Published: July 2010

Ultrafiltration was used in a one‐step method to purify and concentrate biosurfactants—surfactin and rhamnolipids—from culture supernatant fluids. The ability of surfactant molecules to form micelles at concentrations above the critical micelle concentration allows these aggregates to be retained by relatively high molecular weight cut‐off membranes. Lower molecular weight impurities such as salts, free amino acids, peptides and small proteins are easily removed. Various molecular weight cut‐off membranes were examined for the retention of surfactin and rhamnolipids (mol. wts 1036 and 802 respectively). Amicon XM 50 was the superior membrane for retention of surfactin and a 160‐fold purification was rapidly achieved. The YM 10 membrane was the most appropriate for rhamnolipid recovery. Ultrafiltration can play an important role in biosurfactant purification as large volumes of media can be processed rapidly at extremely low cost.
Recovery of uranium by tannin immobilized on matrices which have amino group
Authors: Nakajima Akira , Sakaguchi Takashi
Published: July 2010

Tannin, which contains polyhydroxy groups, has a high affinity for uranium. Various tannin–protein complexes were prepared to develop new adsorbents for uranium recovery from seawater. Albumin tannate has a high ability to adsorb uranium from seawater. Tannin was immobilized on matrices which have multiple active amino groups, such as aminopolystyrene and poly(vinyl‐4,6‐diamino‐s‐triazine)—poly VT. Of these complexes, tannin immobilized on poly VT adsorbed uranium most efficiently from seawater and highly selectively from a solution containing various heavy metals; the uranium adsorption was very rapid and was pH dependent. This adsorbent therefore appears to have potential for use in a commercial process for uranium recovery from seawater or from uranium‐containing waste water.
Synthesis of 9,10‐Bis‐hetaryl anthracenes and their application on polyester fibres as disperse dyes
Authors: Rangnekar D. W. , Rajadhyaksha D. D.
Published: July 2010

9,10‐Dibromoanthracene (2) obtained from anthracene by bromination was reacted with cuprous cyanide in refluxing DMF to obtain 9,10‐dicyanoanthracene (3). The key intermediate (3) was condensed with orthophenylenediamine (4a), ortho‐aminophenol (4b) and dicyanodiamine (6) to give 9,10‐bis(benzimidazol‐2‐yl)anthracene (5a), 9,10‐bis(benzoxazol‐2‐yl)anthracene (5b) and 9,10‐bis(4,6‐diamino‐S‐triazin‐2‐yl)anthracene (5c), respectively. The spectral properties of 5a‐5c were studied. These compounds, when applied as disperse dyes on polyester fibres, gave excellent results.
Kinetics and mechanism of homogeneous catalytic hydroxylation of maleic acid by hydrogen peroxide. Part I: Formal kinetics
Authors: Oludipe John O. , Koiki Kolawole K. , Litvintsev Igor Yu. , Sapunov Valentin N.
Published: July 2010

The kinetics of maleic acid hydroxylation by H2O2 in the presence of a homogeneous catalyst have been studied. A rate equation for the consumption of H2O2 has been obtained. The retardation of the reaction resulting from catalyst deactivation was observed. The fall in the activity of catalyst during the course of the reaction has been associated with the formation of a complex between the former and the reaction product.
Landfill co‐disposal of phenol‐bearing wastewaters: Organic load considerations
Authors: Watson‐craik Irene A. , Senior Eric
Published: July 2010

A multi‐stage model, operated with single elution, was used to investigate the effects of organic loadings on the attenuation of a model phenolic wastewater in domestic refuse. Although 100% dissimilation of influent phenol (2–5 mmol dm−3) was recorded at a dilution rate of 0.007 h−1, partial inhibition of both phenol degradation and species competing with methanogens for a common electron donor(s) was apparent at concentrations ±4 mmol dm−3. On extended perfusion with 8 mmol phenol dm−3, the progressive inhibition of phenol dissimilation was not obviated by nutrient supplementation. Simultaneous degradation of the catabolic intermediate, hexanoic acid, and elevated methane release rates suggested that the transformation of phenol to hexanoate was rate limiting.
Comparison of oxygen supply methods for cultures of shear‐stress sensitive organisms including animal cell culture
Authors: Mano Takashi , Kimura Tatsuro , Lijima Shinji , Takahashi Katsuroku , Takeuchi Hiroshi , Kobayashi Takeshi
Published: July 2010

In animal cell culture, oxygen supply sometimes limits cell growth. Therefore, four oxygen supply methods (free surface aeration, porous Teflon tubing, perfluorocarbon addition and external aerator) were compared in terms of oxygen transfer rate for suspension culture of animal cells. Oxygen transfer rate with the free surface aeration was dependent on the vertical position of the impeller and the stirred Reynolds number for h/HL >0.35, but no effect of the impeller position was observed for h/HL < 0.35. The relationship between the Reynolds and Sherwood numbers could be expressed by simple correlations. These correlations could also be applied to oxygen transfer using porous Teflon tubing. When oxygen was supplied with perfluorocarbon saturated with air, the overall mass transfer coefficient KL was estimated to be about 9.0 × 10−3 cm s−1, which was five‐fold greater than that of the surface aeration. Maximum cell densities which would be supported by four methods were calculated from values of KLa for different sizes of fermentor assuming that oxygen supply would be the rate‐limiting factor in animal cell culture.
Performance analysis of an immobilized yeast packed‐bed reactor for ethanol fermentation
Authors: Ching Chi‐Bun , Teo Wah‐Koon , Chu Khim‐Hoong
Published: July 2010

The performance of an immobilized packed‐bed bioreactor for continuous ethanol fermentation was evaluated. Immobilized yeasts were prepared by entrapment in calcium alginate gel. An axial dispersed plug flow model incorporating the effects of substrate and product inhibition on fermentation kinetics was developed. The model equations were solved by the method of orthogonal collocation and the suitability of the reactor model to predict the conversions obtained in this biocatalytic reaction system was assessed.
The surface activity of triisooctylamine and the mechanism of palladium (II) extraction by dihexyl sulphide in the presence of triisooctylamine
Authors: Szymanowski J. , Bauer D. , Cote G. , Prochaska K.
Published: July 2010

The interfacial activities of triisooctylamine, dihexyl sulphide and dodecylmethyl sulphide were studied and used to discuss the mechanism of palladium (II) extraction from acidic chloride solutions by a mixture of dialkyl sulphide with triisooctylamine. The surface excess isotherms were computed and amine association was considered. The extraction occurs probably according to a complex interfacial‐bulk mechanism in which the reaction between palladium and protonated amine occurs mainly in the bulk of the aqueous phase but the intermediate complex R3NHPdCl3 adsorbs at the interface and reacts with dialkylsulphide in the limiting step.
An investigation of engineering parameters for the use of immobilized biomass particles in biosorption
Authors: Tsezos Marios , Deutschmann Ake A.
Published: July 2010

Immobilized, inactive mycelia of Rhizopus arrhizus are preferential to native biomass for use in the biosorption of metal ions. Refinement of a proprietary immobilization technique previously developed at McMaster University enabled production of particles of immobilized Rhizopus arrhizus biomass having a 12–23% wt of polymer additive. The effects of production stage parameters on the intrinsic uptake capacity of the immobilized biomass were examined. Kinetic experiments showed the following trends: a decrease in the weight percent of the added polymer leads to an increase in the apparent uranium uptake capacity of the immobilized biomass particles far a given contact time. A decrease in the particle size improved the kinetics of metal uptake and led to an increase in the apparent uranium uptake capacity for the same contact time. An increase in the initial concentration of the uranium solution caused equilibrium conditions to be attained faster.
1,5‐Dihydroxy‐4,8‐diamino‐ and 1,8‐dihydroxy‐4,5‐diaminoanthraquinone‐β‐ethers and thioethers. Blue dyes for synthetic polymer fibres
Authors: Peters Arnold T.
Published: July 2010

Condensation of mono‐ and di‐bromo‐derivatives of 1,5‐dihydroxy‐4,8‐diaminoanthraquinone and of 1,8‐dihydroxy‐4,5‐diaminoanthraquinone with phenols and thiols afforded the corresponding β‐ethers and thioethers. These compounds coloured polyester in bright reddish‐blue to greenish‐blue hues of generally good fastness to light and sublimation. The colour of the dyes is discussed with respect to the nature and orientation of the β‐substituent.
High selective production of tetrahydrofurfuryl alcohol: Catalytic hydrogenation of furfural and furfuryl alcohol
Authors: Merat Nadine , Godawa Christine , Gaset Antoine
Published: July 2010

Tetrahydrofurfuryl alcohol could be obtained by catalytic hydrogenation of either furfural or furfuryl alcohol using Pd‐, Ru‐, Rh‐ and Ni‐supported catalysts as well as their mixtures with a Cu‐supported catalyst. In the case of furfural hydrogenation, the best results (97 % yield, 100 % conversion, 98 % selectivity) were obtained in the presence of Ni and Cu. However, this catalytic mixture could not be recycled. In the case of furfuryl alcohol hydrogenation, Ni‐supported catalysts were the most active. Nickel‐onsilica‐alumina catalyst containing 59 % of metal lead to the best results (98–99 % yield, selectivity and conversion >99 %). Moreover, it could be recycled. Hydrogenation of furfuryl alcohol in the presence of this catalyst was the best procedure for the production of tetrahydrofurfuryl alcohol.
Dispersed‐phase holdup and mass transfer in a rotating disc contactor with perforated skirts
Authors: Kawase Yoshinori
Published: July 2010

Dispersed‐phase holdup and extraction efficiency were measured in a pilot‐plant scale rotating disc contactor (RDC) with perforated skirts (RDCS) with kerosene‐o‐cresol‐water system. The data for the RDCS were examined using the data in this work and the available correlations proposed for the plain RDC. A comparison between the data measured in the RDCS and those in the RDC indicated that the RDCS has rather better extraction efficiency compared with the RDC.
The influence of physicochemical properties of ZSM‐5 on catalytic dewaxing
Authors: Sivasanker S. , Waghmare K. J. , Reddy K. M. , Kothasthane A. N. , Ratnasamy P.
Published: July 2010

A decrease in the crystallite size increases the activity as well as the selectivity and reduces the deactivation of ZSM‐5 zeolites in the dewaxing of petroleum fractions. Isomorphous replacement of Al3+ by Fe3+ reduces the dewaxing activity but enhances the yield of dewaxed oil and gasoline at the expense of C1‐C4 gases. Within limits, the Si/Al ratio does not affect the performance of ZSM‐5 zeolite in the hydrodewaxing process.
Study of the mechanism of pore diffusion in batch adsorption systems
Authors: McKay Gordon , Al‐Duri Bushra
Published: July 2010

In this study the film‐pore diffusion model was applied to describe system transport kinetics of three basic dye‐carbon systems, namely Basic Blue 69, Basic Red 22 and Basic Yellow 21. The mass transfer parameters evaluated were the external mass transfer coefficient kf (cm s−1) and the effective diffusivity Deff (cm2 s−1).

A single kf value was sufficient to describe each dye system: these were 0.15 × 10−2, 0.20 × 10−2 and 0.50 × 10−2 cm s−1 for BB69, BR22 and BY21, respectively. The effective diffusivity was found to have values much larger than those of pore diffusivities calculated from liquid diffusivities and its value decreased with increasing initial dye concentration. This was attributed to the effect of surface diffusion, hence pore diffusivity was exchanged by the effective pore diffusivity in the model.

The present model was solved by the exponential curve fit technique; results were expressed in the form of experimental and theoretical Sherwood Numbers compared in terms of the residual.
Lightfastness modelling of azo dyes bearing heteroaromatic substituents
Authors: Carpignano Rosarina , Savarino Piero , Viscardi Guido , Barni Ermanno , Baroni Massimo , Clementi Sergio , Cruciani Gabriele
Published: July 2010

Lightfastness for a number of azo dyes bearing heteroaromatic substituents was modelled by the partial least squares method (PLS) in terms of structural descriptors, involving the principal properties of usual substituents, and the chemical shifts of the heteroaromatic moieties. The model permits the prediction of possible structures, with higher values of the technological property, worthy of synthesis.
Hydrocarbon conversions with some intermetallic catalysts
Authors: Bahia A. , Brown J. M. , Caga I. T. , Harris I. R. , King C. E. , Winterbottom J. M.
Published: July 2010

The intermetallic pseudo‐binary alloys of the general type ZrRh3‐xPdx and ZrRh3‐xRux (0 < × < 3) have been prepared by argon arc melting and melt quenching of the constituent elements.

The alloys were powdered and employed as catalysts for (i) hydrogenation of oct‐1‐yne in the liquid phase at 101.32 kPa total pressure and 70°C, (ii) hydrogenation of buta‐1,3‐diene in the gas phase at 101.32 kPa total pressure in the temperature range 45–225°C, and (iii) hydrogenolysis of n‐pentane in the gas phase at 101.32 kPa total pressure and in the temperature range 200–400°C.

Activity and selectivity measurements were made with respect to (i) alkene formation for the hydrogenation reactions, and (ii) C2 + C3‐alkane formation for the hydrogenolysis reaction. The activity of the alloy series appears to correlate to some degree with the electronic properties and hydrogen sorption capacity of the intermetallic alloys. Auger electron spectroscopy measurements revealed that for ZrRh3‐xPdx alloys both the surface and bulk compositions were in good agreement; this behaviour is contrasted briefly with that of CeRh3‐xPdx alloys which, unlike ZrRh3‐x alloys, suffered significant oxygen interaction in the surface and sub‐surface layers, although this did not affect Rh:Pd ratios.

Catalysts that were active for hydrogenation were inactive for hydrogenolysis and vice versa. However, selectivity values for the hydrogenation reactions generally reflected the behaviour of the predominant noble transition metal. Again, the behaviour of ZrRh3‐xPdx and CeRh3‐x alloys is contrasted, since the latter were more selective for butene formation from buta‐1,3‐diene, and attributed to the oxygen Contamination of the surface. Further more, the selectivity of both ZrPd and CePd, for 1‐octyne and butu‐l j‐dene hydrogenation was significantly greater than that of palladium by virtue of the fact that the intermetallics were found to be largely inactive for alkene hydrogenation.
Selective hydrogenation of styrene. II. Poisoning of Pd/Al2O3 by thiophene and pyridine
Authors: L'Argentiere Pablo C. , Fígoli Nora S.
Published: July 2010

The poisoning of a commercial Pd/Al2O3 catalyst by pyridine and thiophene during the selective hydrogenation of styrene to ethylbenzene was studied. It was found that the Pd electronic state is the main factor controlling the interaction between the metal and the poisons. Pyridine added to the non‐poisoned feed in a pulse produces a modification in the Pd electronic state and a decrease in conversion, but, within certain limits, inhibits the adsorption of more pyridine or thiophene molecules.
A mathematical model of a fluidized bed reactor for the continuous production of solvents by immobilized Clostridium acetobutylicum
Authors: Qureshi Nasibuddin , Maddox Ian S.
Published: July 2010

A fluidized bed reactor has been employed for the continuous production of solvents from whey permeate using cells of Clostridium acetobutylicum immobilized by adsorption onto bonechar. Substrate diffusion equations have been developed for the bioparticles, and a mathematical model has been advanced to describe the operation of the reactor. The model was fitted to the experimental data using the concept that not all of the biomass within the reactor was active in solvent production. On this basis, less than 5% was ‘active’ biomass.
A pH‐controlled fed‐batch process for dextransucrase production
Authors: Brown Donald E. , McAvoy Alexander
Published: July 2010

A fed‐batch culture of Leuconostoc mesenteroides has been operated from an initial volume of 4 dm3 using a sucrose/NaOH solution feed on demand with pH control. An enzyme concentration of greater than 300 DSU cm−3 was achieved in 15 h. A yield of 0.107 kg cells kg−1 sucrose feed was determined. The enzyme production was growth associated at 2.67 × 107 DSU kg−1 cells produced. Growth was shown to be linear and attributed to an unknown conservative trace nutrient limitation associated with the yeast extract.
Transient response of a solid‐liquid model biological fluidised bed to a step change in fluid superficial velocity
Authors: Poncelet Denis , Naveau Henry , Nyns Edmond‐Jacques , Dochain Denis
Published: July 2010

The evolution of a solid‐liquid model biological fluidised bed under a step change in fluid superficial velocity is described. During a transient step change, the fluidised bed divides into a top zone which remains at the initial porosity and a bottom zone which settles at the final porosity. The interface of discontinuity in porosity moves progressively upwards through the fluidised bed. The velocity at which the top of the fluidised bed expands or contracts and the upward velocity of the porosity transition interface depend only upon the initial and final states of the bed porosity and the fluid superficial velocity. This results in a linear evolution with time of the total bed height and the height of porosity transition interface. The proposed model is well suited to describe the transient response of low‐density particles in a fluidised bed, such as encountered in biological systems, to a sudden change of liquid superficial velocity. The model was validated experimentally.
Optimisation of production conditions for 4‐hydroxy‐2,6‐dioxabicyclo(3,3,0)octan‐8‐one[1S,4S,5R] by catalytic oxidation
Authors: Jacquet Fabienne , Rigal Luc , Gaset Antoine
Published: July 2010

The 4‐Hydroxy‐2,6‐dioxabicyclo(3,3,0)Octan‐8‐one[1S,4S,5R], monoketone, is obtained by catalytic oxidation of isosorbide—or 2,6‐dioxabicyclo(3,3,0)4,8‐octandiol[1R,4S,5R,8R]—in an aqueous solution with a stream of oxygen and in the presence of a platinum on carbon catalyst. Setting up sequentially two experimental designs made it possible to study the three main factors which influence the monoketone formation in the case of two reactors of different size and profile. Optimisation of selective and/or quantitative conditions is carried out by comparing response surfaces. Several functional configurations for a discontinuous reactor under agitation are proposed as a function of the constraints chosen.
Assessment of acid hydrolysates of peat as substrate for Scytalidium acidophilum ATCC 26774 fungus
Authors: Martin Antonio M. , Chintalapati Sharada P. , Hoover Ratnajothi
Published: July 2010

The acid‐resistant fungus Scytalidium acidophilum ATCC 26774 was cultivated in submerged fermentation in hydrolysates of Sphagnum peat moss produced with H2SO4, HCl, HNO3 and H3PO4 acids. Hydrolysis with H2SO4 produced the highest concentration of total carbohydrates and reducing sugars in the hydrolysates. However, when Scytalidium acidophilum ATCC 26774 was grown in undiluted hydrolysates, the H3PO4 medium produced the best mycelial growth. The H2SO4 medium produced the highest dry biomass concentration (3.5 g dm−3) obtained with water‐diluted, non‐supplemented peat hydrolysates. Supplementation of diluted H2SO4 hydrolysates with 3 g dm−3 yeast extract and 0.4 g dm−3 MgSO4 considerably enhanced the growth, up to 5.9 g dm−3 dry fungal biomass.

The biomass composition of Scytalidium acidophilum ATCC 26774 grown in the medium which produced the best growth was determined, revealing a relatively high protein content of 37.5% of the dry mycelial weight.
Oxidative detoxification of aqueous bark extracts. Part I: Autoxidation
Authors: Field Jim A. , Lettinga Gatze , Habets Leo H. A.
Published: July 2010

The aqueous extracts of bark were studied as a model for wet debarking wastewater. These extracts are known to contain a high concentration of methanogenic toxic tannins. The objective of this study was to modify the native bark tannins (oligomers) with oxidative methods in order to decrease their methanogenic toxicity. The tannins were polymerized by autoxidation, forming colored high‐molecular‐weight tannins that were non‐toxic to methanogenic bacteria. The autoxidation of pine bark extracts provided complete detoxification. In the case of spruce bark, which was responsible for extracts of higher toxicity, the detoxification was either partial or complete depending on the specific sample of spruce bark from which the extract was prepared. The autoxidation of birch bark did not result in significant detoxification. Although the oligomeric tannins were effectively polymerized, birch bark extracts contain non‐tannin toxins which were not affected by the autoxidation and evidence that highly toxic intermediates were formed during the high pH autoxidation of birch bark extracts is presented.

Autoxidative detoxification offers an interesting approach for pretreating coniferous bark wastewaters. The oxidation reactions of the pretreatment serve to detoxify the largely non‐BOD tannin fraction. Thus the methanogenic bacteria are not inhibited during the anaerobic wastewater treatment for removing BOD.