bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stabilisation in bacillus stearothermophilus of a recombinant plasmid carrying the homologous α‐amylase gene
Authors: Aiba Shuichi , Monden Yoshiaki , Ohnishi Masatoshi , Koizumi Jun‐Ichi , Ming Zhang 
Published: July 2010

AbstractThe phenotypic stability of the recombinant plasmid pAT9 (11.5 MD), which contained the cloned α‐amylase gene from B. stearothermophilus, was studied in batch and continuous culture. Irrespective of the type of culture (batch or continuous; or using glucose or maltose as carbon source), deletion plasmids of the phenotype KmrAmy− the same size (7.3 MD) emerged with time. DNA sequencing analysis and Southern hybridization of a region adjacent to both ends of the pAT9 HindIII fragment containing the α‐amylase gene showed that almost the entire part of the HindIII fragment was lost. Homology between fragments contiguous to the pAT9 HindIII terminals allowed exclusion of a fragment that did not encode the α‐amylase gene and a new recombinant plasmid, pATHP9 (KmrAmy+; 7.5 MD), was constructed which had enhanced phenotypic stability in B. stearothermophilus.
Kinetics of esterification of benzyl alcohol with acetic acid catalysed by cation‐exchange resin (Amberlyst‐15)
Authors: Roy Ratul , Bhatia Subhash 
Published: July 2010

AbstractEsterification of benzyl alcohol with acetic acid catalysed by Amberlyst‐15 (cation‐exchange resin) was carried out in a batch reactor in the liquid phase in the temperature range 328–359 K and at 1 atm. The reaction rate increased with increase in catalyst concentration and reaction temperature. Resin particle size and stirrer speed had virtually no effect on the rate under the experimental conditions. The rate data were correlated with a kinetic model based on homogeneous reaction. The apparent activation energy was found to be 73.3 kJ mol−1 for the formation of benzyl acetate.
The growth of FeOOH microcrystals and chemisorption rate of NO
Authors: Kaneko Katsumi , Inouye Katsuya 
Published: July 2010

AbstractThe adsorption of NO over a period of 1 ms–1 min on α‐ and γ‐FeOOH with different degrees of crystallization has been examined in order to clarify the fast chemisorption phenomenon. The FeOOH crystals were prepared under the conditions of various reaction temperatures and ageing times. The changes in X‐ray diffraction patterns, particle size, specific surface area and electrical conductivity were examined. The fast chemisorption rate constant, kf, for NO was obtained at 30°C from the conductivity change in the initial stage of NO adsorption. The α‐FeOOH aged for 2 days and 6 days, the crystallite size of which approximately 100 Å gave the highest kf and the greatest amount of chemisorption; the high activity is assumed to be caused by a special surface structure accepting NO molecules. The maximum kf for α‐FeOOH was also for a crystallite size of approximately 100 Å. As the change of kf with crystal growth for γ‐FeOOH is similar to that of electrical conductivity, an electronic factor seems to be most important in the fast chemisorption process of NO on γ‐FeOOH.
Facilitated mass transfer in a packed‐bed immobilized‐cell reactor by using an organic solvent as substrate reservoir
Authors: Brink Lowie E. S. , Tramper Johannes 
Published: July 2010

AbstractThe production of propene oxide from propene and oxygen by non‐growing cells entrapped in calcium alginate was used to study the behaviour of a packed‐bed immobilized‐cell reactor operated with an organic solvent as the substrate reservoir. As a result of the high solubility of propene in the solvent used, n‐hexadecane, oxygen was considered to be the limiting substrate. Dilution of the biocatalyst bed with small glass particles appeared necessary to attain a high liquid/solid contacting efficiency between the hydrophilic gel particles and the hydrophobic solvent. The bed dilution had the advantage of avoiding bed compaction and reducing pressure drops. The use of an organic solvent as the transport medium prevented oxygen depletion along the length of the packed‐bed reactor. This eliminated the need for a separate gas phase in the bioreactor. A mathematical reactor model was developed to describe the combined effects of contacting pattern and external and internal diffusion limitations on the instrinsic kinetics of the immobilized cells. Experiments with the packed‐bed immobilized‐cell reactor were performed using an aqueous solution or n‐hexadecane as the reaction medium. Predicted oxygen conversions compared favourably to the observed values without the need for fitting factors.
Adsorption of petroleum sulfonate TRS 10‐80 on a mineral sand
Authors: Singh Vimal Sheel , Pandey Birendra Prasad 
Published: July 2010

AbstractAdsorption of petroleum sulfonate TRS 10‐80 on a mineral sand, characterized by chemical analysis and infrared spectra to be silica, has been studied under conditions relevant to the practical field. The adsorption is significantly affected by the age of the sulfonate solutions. A new mechanism of adsorption involving sulfonate monomers and multimers has been proposed. The adsorption behavior is best characterized by Langmuir and Freundlich models. At higher temperatures, the mineral surface seems to be capable of forming chemical bonds with the sulfonate anions. Micelles are not considered to be the species favored for adsorption. The adsorption, depending upon the concentration of added electrolyte, either reaches a saturation value or decreases abruptly after a fixed surfactant concentration has been reached. The apparent surfactant loss at higher salt concentrations seems to be due to salting‐out of the sulfonate rather than its adsorption.
Adsorption of pollutants on to activated carbon in fixed beds
Authors: McKay Gordon , Bino Murad J. 
Published: July 2010

AbstractThe adsorption of certain pollutants, namely phenol, p‐chlorophenol, sodium dodecyl sulphate and mercuric ions, on to activated carbon has been studied using fixed bed systems.There are three main methods of contacting in solid/liquid adsorption systems, namely batch, fixed bed and fluidized bed systems. In fixed bed adsorption the adsorption rate is determined on the basis of adsorption equilibrium (unfavourable, linear, favourable or completely irreversible) and the controlling mechanism (external film mass transport, internal pore diffusion, internal solid phase diffusion or longitudinal diffusion). One or more of the previous transport mechanisms may be rate controlling depending on the solute‐adsorbent system. For an adsorbent like activated carbon which is highly porous both external transport and pore diffusion will be very important. An adsorption model, based on external mass transport and internal pore diffusion, has been applied to the systems to predict theoretical breakthrough curves. These curves have then been compared with experimental data and using a ‘best fit’ technique, an effective pore diffusion coefficient can be determined for each sorbate–carbon system.
Reaction of amines with conjugated olefins using lithium naphthalenide in non‐ethereal solvents
Authors: Sugahara Kotoji , Fujita Tsutomu , Watanabe Shoji , Hashimoto Hiroyuki 
Published: July 2010

AbstractIt was found that lithium naphthalenide can be prepared from metallic lithium cuttings and naphthalene in non‐ethereal solvents, such as benzene–N,N,N′,N′‐tetramethylethylenediamine (TMEDA) or benzene‐N,N,N′,N′‐tetramethyldiaminopropane (TMDAP), under ultrasonic irradiation. Secondary amines reacted with conjugated olefins, such as isoprene or myrcene, using lithium naphthalenide in such non‐ethereal solvents to give allylic amines. The yields of products were higher than in the reaction using lithium naphthalenide in tetrahydrofuran. From diethylamine (I) and isoprene (II), a mixture of N,N‐diethyl‐3‐methyl‐2‐butenylamine (IV) and N,N‐diethyl‐2‐methyl‐2‐butenylamine (V) (IV:V = 79:21) was obtained in 77% yield, and from diethylamine (I) and myrcene (III), N,N‐diethylgeranylamine (VI) and N,N‐diethylnerylamine (VII) (VI:VII = 88:12) were produced in 72% yield. These terpenic amines, VI and VII, are used as starting compounds for the preparation of perfumery materials.
Selective toluene disproportionation over ZSM‐5 zeolites
Authors: Meshram Namdeo R. 
Published: July 2010

AbstractSelective toluene disproportionation to benzene and xylenes is investigated over HZSM‐5 and modified HZSM‐5 zeolites. The zeolites are modified with nickel, magnesium, phosphorus and boron, characterised by sorption, acidity measurement and X‐ray photoelectron spectroscopy, and their activity towards toluene disproportionation is discussed in the light of their physico‐chemical properties. The two types of active sites have been identified; one promoting disproportionation and the other cracking and dealkylation of toluene. It is found that the latter sites are suppressed due to incorporation of the modifiers. The modified zeolites are found to be para‐selective which appears to be consistent with the commonly accepted view that modifiers like magnesium, phosphorus and boron reside in the channels and react with Brønsted acid sites, leading to partial blockages and thus favouring the formation of p‐xylene. The effect of poisoning the zeolite with 1‐methylisoquinoline is also investigated. In the case of poisoned catalyst, p‐xylene is produced at levels up to 99%. The total elimination of other isomers from the products is suggested due to the selective poisoning of the non‐selective sites (on the external crystal surface) and to partial blocking of the pore openings.
Influence of roasting temperature on reactions between ferruginous blende and copper(II) oxide
Authors: Ghodsi Mehdi , Detournay Jacquy , Schrobiltgen Jean‐Marie , Naessens Georges 
Published: July 2010

AbstractThermal treatment in an oxidizing atmosphere of a mixture of raw blende (ZnS) and copper(II) oxide enhanced the formation of a mixed ferrite phase at temperature about 600°C. The composition established at 900°C was approximately (0.8 ZnO · 0.2 CuO)Fe2O3.For the mixture ZnS–CuO, with 5 to 15% CuO by weight, less than 15% copper was involved in the formation of the spinel phase.The increasing copper content in the mixture, roasted above 1000°C, favoured solubilization of iron, even in a weakly acid medium.
The effects of whey cations on the kinetic parameters of a model for the enzymic hydrolysis of lactose
Authors: Agbebavi J. Tonyi , Rouleau Denis , Mayer Raymond C. 
Published: July 2010

AbstractThe effects of whey cations (Ca2+, Mg2+) on the enzymic hydrolysis of lactose have been studied, at temperatures in the range 30–50°C, in a continuous stirred tank reactor (CSTR), using an immobilized β‐galactosidase (Novozym 231). A model for the variation of Vmax (the maximum rate in the Michaelis—Menten expression) in the presence of the ionic environment has been developed based on the Gouy electrical double layer concept and the liquid phase bimolecular process. In the presence of one cation (Mg2+), the mean value of the model parameter av, an approach distance including the hydration radius of the protein, was 27 × 10−10 m, almost identical to the value obtained by the crystal density method. When two cations (Mg2+ and Ca2+) were present simultaneously the value of Vmax as a function of the ionic strength showed a maximum which may be explained by the Stern adsorption modification of the Gouy theory.
The manufacture of microporous membranes and their structure and properties
Authors: Meares Patrick 
Published: July 2010

AbstractMicroporous membranes suitable for use in ultra‐ and microfiltration can now be made from a wide range of inorganic and organic materials. Inorganic membranes are made by methods derived from practices that are standard in the ceramics industry. Organic membranes are made from synthetic and modified natural polymers either in the dry state by exploiting anisotropic mechanical properties or from solutions of the polymer by one of the several versions of the phase inversion process. Thanks to the good understanding of the thermodynamic and kinetic properties of polymer‐liquid systems resulting from 50 years of careful research, the morphology of asymmetric membranes made by phase inversion can be controlled in fair detail. This short article surveys the methods of manufacturing membranes in relation to their structures.
Optimal separation of n‐paraffins from Kuwait kerosene using a molecular sieve adsorbent
Authors: Al‐Damkhi A. M. , Al‐Ameeri R. S. , Jeffreys G. V. , Mumford C. J. 
Published: July 2010

AbstractA study has been made of the vapour‐phase adsorptive separation of n‐alkanes from Kuwait kerosene using zeolite molecular sieves (LMS‐5A). The object was to identify the optimum operating conditions, in terms of flow rate, adsorption temperature and zeolite particle size for the separation of n‐alkanes from kerosene, so that the remaining stock would also be of marketable quality. The effect of these conditions on the height of the mass transfer zone (HMTZ) and the dynamic capacity (Ad) of zeolite was also investigated.The adsorptive separation process comprised one cycle of adsorption using a fixed bed of zeolite type‐5A. The bed was fed with kerosene vapour until equilibrium had been achieved, whereby the n‐paraffins were adsorbed and the denormalized material excluded. The processes were carried out isobarically at one atmosphere.The optimum operating conditions were found to be a feed flow rate of 33.33 × 10−9 m3 s−1, an adsorption temperature of 643 K and a zeolite pellet fraction size of 1.0–2.0 × 10−3m. This yielded an HMTZ value of 0.206 m and an Ad of 9.653 × 10−2 kg n‐paraffins kg−1 zeolite. The data will serve as a basis for the design of commercial plant.
Removal of phenols by adsorption on fly ash
Authors: Kumar Satendra , Upadhyay S. N. , Upadhya Y. D. 
Published: July 2010

AbstractAdsorption of phenol and cresol and their mixtures from aqueous solutions on activated carbon and fly ash has been investigated. The effects of contact time and initial solute concentration have been studied and isotherm parameters are evaluated. The Freundlich isotherm has been found to be more suitable for all the systems investigated.
Catalyst preparation and support effects for triglyceride hydrogenation over supported nickel
Authors: Chung Chun‐Shun , Winterbottom John M. 
Published: July 2010

AbstractNickel catalysts have been prepared by impregnation and precipitation methods on silica and charcoal. Metal loadings were in the range 1–40% w/w Ni on the support.The catalysts were investigated by temperature programmed reduction (TPR) and subsequently reduced in the temperature range 200–500°C. Metal surface areas were measured via H2 and CO chemisorption and limited studies of the catalysts were carried out using X‐ray photon spectroscopy (XPS), X‐ray diffraction (XRD) and transmission electron microscopy (TEM) to determine the chemical and physical state of the nickel after reduction. Reduced catalysts were employed for triglyceride (soya bean oil) hydrogenation (1 atmos H2, 160°C) in a stirred reactor (1000 rpm) and reaction rates (catalyst activity) and product distributions were determined.Charcoal supported catalysts were active and zero valent nickel was detected after reduction. However, surface areas were variable, the performance of such catalysts being affected by pore effects, agglomeration and possibly nickel–charcoal interaction.Silica supported precipitated catalysts were of relatively high activity and metal surface if methanol washed before activation and inactive (irreducible) if only water washed.Although silica supported precipitated catalysts were more active per unit weight of metal than charcoal supported counterparts, they were less active per unit metal area and gave rise to greater trans‐acid production. This may be due to triglyceride molecules excluding hydrogen from small nickel crystallites.
On‐line measurement and control of penicillin V production in a tower loop reactor
Authors: Lorenz Th. , Diekmann J. , Frueh K. , Hiddessen R. , Moeller J. , Niehoff J. , Schügerl K. 
Published: July 2010

AbstractPenicillin V was produced in a 98‐dm3 tower loop reactor using a production strain of Penicillium chrysogenum in pellet form. By using control devices, the aeration, the only energy input in a tower loop reactor, decreased by an average of 75%. The amounts of precursor substance (phenoxyacetic acid), acid, base, ammonium sulfate and urea, added during the penicillin fermentation process, were reduced by applying an automatic analysing system to the process.
Extractive distillation of propanol–water mixtures employing less‐soluble and sparingly soluble salts as separating agents
Authors: Zaidi Syed A. H. 
Published: July 2010

AbstractExtractive distillation of 1‐propanol and 2‐propanol from the respective organo‐aqueous mixtures employing less soluble (Na IO3, K2SO4, PbCl2) and sparingly soluble salts (Ca(OH)2, CaSO4, BaSO4, PbSO4, PbCO3) dissolved to saturation in the boiling liquid phase at atmospheric pressure has been examined. The 98% purification of 2‐propanol obtained with Ca++−, Pb++ and Ba++ salts suggests large perturbation of phase equilibria with relatively small salt concentrations (9 × 10−6 M for Pb++) on the 2‐propanol‐water system.
Role of pretreatments on enzymatic hydrolysis of agricultural residues for reducing sugar production
Authors: Tewari Harmesh K. , Singh Lokendra , Marwaha Satwinder S. , Kennedy John F. 
Published: July 2010

AbstractThe ability of agricultural residues, namely wheat straw, sugarcane bagasse, groundnut shell and corn‐cob, for supporting cellulase production in Trichoderma reesei QM 9414 and the effect of pretreatments by chemical and physical agents on enzymatic hydrolysis of the residues have been investigated. Crystalline cellulose was used for comparison. Wheat straw supported maximum cellulase activities (FPA 111.11 IU g−1 substrate; CMCase 277.77 IUg−1 substrate; cellobiase 12.04 IU g−1 substrate) under submerged fermentation conditions at the end of six, six and ten days of incubation, respectively. The pretreatment of lignocellulosic wastes using both chemical and physical agents improved the enzymatic hydrolysis of the substrates. However, the nature and duration of delignification process of the cellulosics varied with the substrate. The treatment of sugarcane bagasse, corn‐cob and wheat straw using sodium hydroxide at a rate of 0.5% w/v with autoclaving for 1.5 h, 1.5 h and 0.5 h, respectively, was found to be optimum and resulted in the formation of reducing sugars of the order of 896 mg 10 g−1 of sugarcane bagasse, 760 mg 10 g−1 of corncob and 632 mg 10 g−1 of wheat straw. Among the physical agents, grinding of the groundnut shell to a particle size of 60 mesh was observed to be the most effective for producing maximum reducing sugars.
Microbial mineral processing: The opportunities for genetic manipulation
Authors: Nicolaidis Anthony A. 
Published: July 2010

AbstractApplications of microbiology to mining operations have been surveyed and evaluated. This has been carrried out with a view to seeking directions whereby genetical and molecular biological approaches could be applied to optimise ‘bio‐mining’ processes. Copper and uranium are currently recovered from their ores on a commercial scale (to a value of about US$1800 million annually worldwide) using bioleaching systems carried out in the open in biologically uncontrolled conditions. Possibilities also exist for applying bioleaching methods on an industrial scale for the extraction of a number of other metals from sulphide‐bearing concentrates. Molybdenum, cobalt and nickel are likely to be most suitable, principally because of their value. Biological ore beneficiation can be used to enhance the recovery of noble metals. Bioleaching systems offer a variety of desirable advantages compared to conventional methods but suffer principally in their relatively low leaching rates. Opportunities exist for the enhancement of bioleaching rates by genetic technologies. These approaches are outlined and discussed. Bioconcentration systems offer possibilities for metal recovery from dilute industrial waste streams and metal refinery effluents and for the heavy metal detoxification of polluted waters. Possible applications of genetic technologies to bioconcentration systems are proposed. Other uses for the mineral leaching thiobacilli, e.g. fossil fuel desulphurisation, are outlined and discussed.
Cross‐flow separation of yeast cell suspensions using a sintered stainless steel filter tube
Authors: Kavanagh Paul R. , Brown Donald E. 
Published: July 2010

AbstractA new design of cross‐flow filtration unit, the Transep filter, has been investigated for the separation of slurries of Saccharomyces cerevisiae. Porous cylindrical sintered stainless steel tubes of 2 μm and 3 μm nominal pore size ratings were used as filter media. Filtration rates were measured for cell suspensions ranging from 3 to 25 kg m−3. The 3 μm filter produced particle‐free filtrates at average rates from 1.25 m3 m−2 h−1 which declined to half this value over the range of cell concentrations studied.
Preparation of diphenyl acetonitrile by phase transfer catalysis
Authors: Kasarekar Ravindra B. , Sawant Sudhirprakash B. 
Published: July 2010

AbstractPreparation of diphenyl acetonitrile has been investigated by the reaction of diphenyl methyl bromide with aqueous sodium cyanide, using quaternary ammonium salts as phase transfer catalysts. The effect of catalyst, temperature, catalyst loading, and reactant concentration on the conversion of diphenyl methyl bromide to diphenyl acetonitrile has been studied. Suitable process conditions have been established for the production of diphenyl acetonitrile.
Adsorption of thiram from aqueous solution on activated carbon and sepiolite
Authors: Gonzáiez‐Pradas E. , Villafranca‐Sánchez M. , Socias‐Viciana M. , Del Rey‐Bueno F. , García‐Rodriguez A. 
Published: July 2010

AbstractAdsorption of thiram on activated carbon and acid‐heat treated sepiolite from aqueous solution at 10° C, 20° C, 30° C and 40° C has been studied. The adsorption isotherms may be classified as L type of the Giles classification which suggests that there is no strong competition from the solvent for adsorption sites.The experimental data points have been fitted to the Langmuir equation in order to calculate the adsorption capacities of the solids as well as their surface areas available to the thiram molecules. The removal efficiency (P) has been calculated for both adsorbents resulting that activated carbon is more effective (P = 98–100%) in removing thiram from aqueous solution than acid‐heat treated sepiolite (P = 14–52%).
The application of solar energy in water reuse
Authors: Prasad Gur 
Published: July 2010

AbstractThe application of photocatalysed oxidation in water reuse technology is described. Results with a sequencing batch reactor showed that 4 hours contact of the raw sewage with 0·5 mg dye sorbed g−1 fly ash in sunlight, under experimental conditions, significantly reduced the organic and bacteriological load and rendered it fit for use in irrigation or for discharge. The effect of variables such as contact time or amount of dye sorbed on COD, MBAS and MPN counts were investigated and the results interpreted in terms of enhanced photoactivity and biodegradation in the sorbed state. The process appears to be well suited to commercial exploitation as it is safe, quick and economical.
Suitability of spent hydrodesulphurisation (HDS) catalyst in low pressure distillate hydrocracking—a case study
Authors: Mittal Krishan G. , Gupta Sri C. , Agarwal Ravindra K. , Rai Jai R. 
Published: July 2010

AbstractLow pressure hydrocracking (40–80 atm., 425°C and 0·5 liquid hourly space velocity is achieved economically on a low cost spent hydrodesulphurisation catalyst (cobalt—moly/alumina) using vacuum distillate of Indian crudes. Once through, conversion to products boiling below 371°C was in the range 40°69—43·04 wt % with the middle distillate amounting to 32·03–38·24 wt %.