bluuebunny/crossref_metadata_2025_split huggingface dataset:
Water soluble imide—amide copolymers: Iv. Flocculation and surface active properties of poly(acrylamide‐co‐sodium N‐(4‐sulfophenyl)maleimide)
Authors: Hocking Martin B. , Syme David T. , Axelson David E. 
Published: July 2010

AbstractSix new poly(acrylamide‐co‐sodium N‐(4‐sulfophenyl)maleimide) (PAMSM) water‐soluble copolymers have been prepared with several levels of imide ring incorporation into the backbone of the polymer chain to test the effectiveness of increased chain stiffness on the efficiency of fiocculation. Sufficient material was obtained from the synthetic experiments to enable the surface active properties of three of these copolymers to be tested.PAMSM copolymers containing 7, 15, and 25 mol % imide performed poorly compared to commercial partially hydrolyzed polyacrylamides (HPAM) when used to flocculate an aqueous 3% calcium‐montmorillonite suspension at pH 4·0 and pH 7·5. This was probably because of a major difference between the dissociation constants of the anionic functionalities of the new vs existing commercial polymer flocculants, complicated by the possibility that the molecular weights of the new copolymers were too low.The three PAMSM copolymers behaved as dispersants instead of flocculants when tested on a 3% kaolinite suspension in water at pH 4·5. Their effectiveness as dispersants increased with increasing imide content.PAMSM‐1a (7% imide), PAMSM‐3 (25% imide) and polystyrene sulfonate (500 000 mol. wt) all acted as weak dispersants when tested on a 3% hematite suspension in water at pH 4·5, 6–0, and 8·7.
Surface properties of aluminium hydroxide gels prepared from pure and mixed aqueous, ethanolic and acetonic media
Authors: Stalidis George A. , Bakoyannakis Demetris N. , Zamboulis Demetris X. 
Published: July 2010

AbstractThis work deals with the preparation of aluminium hydroxide gels by precipitation from pure and mixed solvents in the presence of propylamine acting as proton acceptor in the hydrolysis reaction. As solvents were used water, ethanol and 50% v/v water‐ethanol and water‐acetone mixtures. Pure acetone could not be used because the aluminium salt used (AlCl3.6H2O) was not sufficiently soluble in it. The samples were freeze‐dried and activated to temperatures up to 773 K. The samples prepared from aqueous solutions showed the structure of poorly crystallized pseudoboehmite, while the sample prepared from pure ethanol was nearly amorphous and presented the highest specific surface area of all the samples (570 m2 g−1 for thermal activation at 473 K). The sample prepared from aqueous acetone exhibited the highest porosity (about 4 cm3 g−1) consisting of pores of nearly uniform size. This porosity remained almost constant throughout the range of thermal activation temperatures.
Effective diffusion coefficient of chloride in porous concrete
Authors: Lin Sheng H. 
Published: July 2010

AbstractA simplified diffusion model is given in the present paper to represent the chloride diffusion in porous concrete. The model with appropriate effective diffusion coefficient is shown to represent equally well as the more complex diffusion/reaction model proposed by Pereira and Hegedus.4 However the present model has the main advantages of being amenable to an analytic solution and ease of model parameter estimation.
Cyclic voltammetric behaviour and some surface characteristics of the lead electrode in aqueous NaBr solutions
Authors: El‐Halim A. M. Abd , Fawzy M. H. , Saty A. 
Published: July 2010

AbstractThe anodic behaviour of the lead electrode in aqueous 0.05–3.00 M NaBr solutions was investigated by means of linear sweep voltammetry. The voltammograms showed one anodic peak current density (jap) corresponding to the formation of a thin passivating layer of PbBr2. The obtained data depicted a gradual increase of jap and shifting of the corresponding potential (Eap) to more negative values with increase of CNaBr.A detailed study of the formation/reduction of PbBr2 on the surface of lead electrodes in aqueous 0.10–1.00 M NaBr solution was carried out by cyclic voltammetry. The results indicated that the formation of PbBr2 is controlled by diffusion of Br− ions to the anode surface. Irrespective the voltammetric conditions, the study proved that the formation/reduction of the PbBr2 surface layer is a reversible process. The role played by the operating voltammetric conditions in the building up of a relatively thick PbBr2 surface layer that could resist rupture and/or breakdown is discussed.The as‐formed PbBr2 layers were examined by scanning electron microscopy and X‐ray diffractometry. The microstructure showed some morphological modifications which could be correlated to the operating conditions. On the other hand, X‐ray diffiaction analysis proved that, under all conditions, the anodic surface products consist solely of PbBr2 in the orthorhombic crystalline structure.
Bubble column fermentation of olive mill wastewaters by Aspergillus niger
Authors: Hamdi Moktar , Ellouz Radhouane 
Published: July 2010

AbstractA bubble column (tower) fermenter was used to study the growth of Aspergillus niger on olive mill wastewaters (OMW). The gas hold‐up, mixing time and oxygen transfer coefficient values were studied in terms of superficial air velocity. These characteristics were clearly affected by OMW. The growth of A. niger resulted in a filamentous suspension with no pellet formation and the specific growth rate was 0–2 h−1. The growth rate was limited by the oxygen transfer rate at 90 mmol dm−3 h−1 when pO2 was lower than 2%.
Studies on the synthesis of SAPO‐5
Authors: Bhattacharya Anjana , Das Jagannath , Mitra Swapan , Roy Sisir K. 
Published: July 2010

AbstractSilicoaluminophosphate (SAPO‐5) molecular sieves have been synthesised from reaction mixtures having a molar composition of: 0.7–1.0 Al2O3:0.7–1.0 P2O5:0.01–2.0 SiO2:xR:40 H2O (where R = (C2H3)3N or (C2H3)4NOH and x = 1.5–2.5 for (C2H5)5N and 0.5 for (C2H5)4NOH, at 473 K using various sources of alumina and silica. The effects of (i) varying the crystallinity of the alumina source (boehmite) and (ii) the use of different silica sources such as freshly prepared silica either from sodium silicate or paddy husk extract, silica gel from commercial water‐glass, and tetraethyl orthosilicate have been studied. The crystallinity of boehmite has been found to have a strong effect on its reactivity towards the formation of SAPO‐5. The activity of boehmite for SAPO‐5 formation increased with a decrease in its crystallinity (or with increase in its moisture content). Any silica source devoid of sodium ions could be employed for the synthesis of SAPO‐5. The process of crystallisation started as early as within 1.5 h of reaction and incorporation of silicon into the AlPO4 framework has been noted at this stage. Formation of some tridymite phase as impurity has been observed under conditions such as (i) SiO2 concentration > 1.7 mole and (ii) x > 2.0 when R = (C2H5)3N.
Kinetics of wine spoilage by acetic acid bacteria
Authors: Kösebalaban F. , Özilgen M. 
Published: July 2010

AbstractAcid production in wines inoculated with acetic acid bacteria from vinegar was studied at 15°C, 20°C, 25°C and 30°C and simulated with kinetic models. Results indicated that major wine spoilage did not occur during the growth of the microorganisms, but during their extended presence at high concentrations during the stationary and death phases. Acetophilic species were observed to resist death, which is in agreement with the mechanism suggested by Kittelmann et al.9 for the development of gradual acid tolerance by acetic acid bacteria.
Local mass transfer measurements from a submerged jet parallel to a flat surface
Authors: Krishna P. Gopala , Das S. C. , Subbaiah T. , Das R. P. 
Published: July 2010

AbstractThe local mass transfer rates from a submerged vertical jet parallel to the vertical electrode surface were measured by a limiting current density technique. For these studies, the parameters considered are a plate Reynolds number in the range of 1965 to 136500, electrode height over the orifice of the jet (Y) which varied from 0 to 12 times the jet orifice diameter (d), and the vertical distance of the microelectrode on the electrode plate in the range of 0.7 to 12.5 cm. The system used for measuring the limiting current was the reduction of copper ions. The relationship between the local Sherwood number (Sh) and Reynolds number (Re) was found to be Sh = 0.0004(Re)1.5 (Sc)0.33This relationship is valid for Y/d ≤ 6.0.
Kinetics and mechanism of homogeneous catalytic hydroxylation of maleic acid by hydrogen peroxide. Part II: Analysis of material balance conformities and the mathematical model
Authors: Oludipe John O. , Koiki Kolawole K. , Litvintsev Igor Yu. , Sapunov Valentin N. 
Published: July 2010

AbstractThe general kinetic laws relating the changes in reactants and products ratios with changes in the operating conditions of the catalytic epoxidation and hydroxylation reaction of maleic acid by hydrogen peroxide have been analyzed. In the course of the hydroxylation reaction, the formation of epoxysuccinic and tartaric acids, and the decomposition of hydrogen peroxide to molecular oxygen have been observed to take place in parallel. The catalytic complex (Cat.2H2T) formed between sodium tungstate (catalyst) and tartaric acid in the course of the reaction is found to be inactive in the epoxidation reaction but active in the catalysis of the decomposition of hydrogen peroxide. This fact explains the non‐formation of tartaric acid at high maleic acid conversion. The mathematical model for the overall process has been developed.
Electrolytic removal of cupric ions from dilute liquors using reticulated vitreous carbon cathodes
Authors: Walsh Frank C. , Pletcher Derek , Whyte Ian , Millington J. Peter 
Published: July 2010

AbstractThe performance of a divided laboratory reactor, which utilises a 5.0 cm × 5.0 cm × 1.2 cm RVC cathode, is examined for copper removal from 0.5 m Na2SO4 solutions at pH 2 under potentiostatic, mass transport controlled conditions. The practical values of kLAe (the product of averaged mass transfer coefficient and cathode area per unit electrode volume) are shown to depend upon the grade of RVC and the electrolyte velocity. The presence of dissolved oxygen decreases the current efficiency but the effect may be minimised by careful choice of the cathode potential. For the 100 ppi material, kLAe values of up to 0.23 s−1 were realised. Even in air saturated solutions, the overall current efficiency was as high as 69% during the reduction of a 10 ppm cupric ion level to less than 0.1 ppm. Normalised space velocity values were in the range 50‐450 m3 m−3 h−1 while the normalised volumetric power consumption was 1.3‐6.4 kW m−3.
Distribution of an enzyme in porous polymer beads
Authors: Ampon Kamaruzaman 
Published: July 2010

AbstractTrypsin has been immobilized by adsorption onto Amberlite XAD‐7 beads. The Michaelis constant (Km) of the enzyme was increased about sevenfold following the immobilization. Its rate of penetration into the porous beads was determined by staining the beads, which had been split, with naphthol blue black. The extent of diffusional rate limitation of immobilized trypsin was related to the penetration depth of the enzyme into the beads. This can be controlled by manipulating the conditions during the preparation of the immobilized enzyme.
A study on the removal of urea from aqueous solution with immobilized urease and electrodialysis
Authors: Huang Ting‐Chia , Chen Dong‐Hwang 
Published: July 2010

AbstractA five‐compartment electrodialyzer with immobilized urease was developed for the removal of urea from aqueous solution. The immobilized urease, supported on polyurethane foam, was placed in the central (dilute) compartment, where urea was hydrolyzed and the products NH4+ and CO32‐/HCO3− were removed simultaneously by electrodialysis. The system was studied both under constant current and under constant voltage. The effects of urea concentration and applied current or voltage on the removal of urea and ammonium ions from the dilute solution were investigated. The variations of the pH of dilute solution, the current or voltage of system, and current efficiency were also examined during reaction‐electrodialysis. The removal of urea by enzymic reaction was not affected significantly by the applied electric field. The current effieiencies for removing ammonium ions from dilute solution were mostly within 40‐80%, and the removal percentage of ammonium ions was dependent on current density and current efficiency.
Oxygen utilisation by isopenicillin n synthase from penicillium chrysogenum
Authors: Bainbridge Zoë A. , Scott Robert I. , Perry David 
Published: July 2010

AbstractThe enzyme isopenicillin N synthase (IPNS) converts δ‐(L‐α‐aminoadipyl)‐L‐cysteinyl‐D‐valine (ACV) to isopenicillin N; an equimolar amount of oxygen is used in this oxidative ring closure reaction. Oxygen uptake rates of the reaction catalysed by partially purified IPNS from Penicillium chrysogenum SC 6140 and P2 were measured using an oxygen electrode. In contrast to published properties of Cephalosporium acremonium IPNS, the enzyme from P. chrysogenum was not stimulated by the addition of glutathione and showed reduced stimulation by Fe2+. The analysis of oxygen uptake rates showed the reaction to be first order with respect to oxygen concentration and the Km for ACV to be 0·4 mmol dm−3. The implications of these results for cell‐free reactions using this enzyme and penicillin fermentations are discussed.
Pore diffusion: Dependence of the effective diffusivity on the initial sorbate concentration in single and multisolute batch adsorption systems
Authors: Al‐Duri Bushra , McKay Gordon 
Published: July 2010

AbstractThe present work studies the intraparticle diffusivity in batch adsorption systems as a function of the initial sorbate concentration. The systems under investigation are basic dyes, namely Basic Blue 69, Basic Red 22 and Basic Yellow 21 and their binary and ternary combinations, all adsorbing onto activated carbon Filtrasorb 400. They study is based on the film‐pore diffusion model and the output is a combination of the external mass transfer coefficient, kf and the effective diffusivity, Deff that yields congruent experimental and theoretical kinetic data.It has been found the Deff varies with Co in an exponential decay function. Furthermore. Deff values undergo a general reduction in the multisolute systems compared to the single component systems. Also, the relative diffusion rates in the multisolute systems are found to change such that Deff of the slower diffuser is enhanced and that Deff of the faster diffuser is inhibited.
Treatment of carpet and metallic effluents by China clay
Authors: Gupta Ghan S. , Singh Arun K. , Tyagi Balbir S. , Prasad Gur , Singh Vishwa N. 
Published: July 2010

AbstractThis paper addresses the treatment of carpet and metallic effluents containing some popular chrome dyes, i.e. Omega Chrome Red ME (CI 18735), Metomega Chrome Orange GL and Omega Chrome Fast Blue B (C.I. 16680) and heavy metals, i.e. iron, zinc and manganese by adsorption on china clay. China clay exhibits a good affinity for Metomega Chrome Orange GL and zinc, significant uptake of Omega Chrome Red ME, manganese and iron but a poor scavenger for Omega Chrome Fast Blue B. High removal of the above pollutants has been noted at low initial concentration. The process of uptake follows a first order adsorption rate expression and obeys Langmuir's model of adsorption. The removal process has also been found to be partially diffusion controlled and mass transfer coefficients have been determined to explain the results. The effect of temperature on the removal of adsorbates has also been studied. Acidic pH has been found to be more effective in the case of dyes and iron while in the case of zinc and manganese a basic pH around 8·0 has showed appreciable results. The effect of pH has been discussed incorporating various surface site reactions.
Continuous ethanol fermentation using immobilized yeast in a fluidized bed reactor
Authors: Nguyen Van T. , Shieh Wen K. 
Published: July 2010

AbstractContinuous ethanol fermentation of glucose using fluidized bed technology was studied. Saccharomyces cerevisiae were immobilized and retained on porous microcarriers. Over two‐thirds of the total reactor yeast cell mass was immobilized. Ethanol productivity was examined as dilution rate was varied, keeping all other experimental parameters constant.Ethanol yield remained high at an average of 0.36 g ethanol g−1 glucose (71% of theoretical yield) as the dilution rate was increased stepwise from 0.04 h−1 to 0.14 h−1. At a dilution rate of 0.15 h−1, the ethanol yield steeply declined to 0.22 g ethanol g−1 glucose (44% of theoretical yield). The low maximum percentage of theoretical yield is primarily due to an extended mean cell residence time, and possibly due to the inhibitory effect of a high dissolved carbon dioxide concentration, enhanced by the probable intermittent levels of low pH in the reactor.Constant ethanol production was possible at a high glucose loading rate of 840 g dm−3 day−1 (attained at a dilution rate of 0.14 h−1). Although the highest average ethanol concentration (97.14 g dm−3) occurred at the initial dilution rate of 0.04 h−1, the peak average ethanol production rate (2.87 g (g yeast)−1 day−1) was reached at a greater dilution rate of 0.11 h‐1. Thus, the optimal dilution rate was determined to be between 0.11 h−1 and 0.14 h−1.Ethanol inhibition on yeast cells was absent in the reactor at average bulk‐liquid ethanol concentrations as high as 97.14 g dm−3. In addition, zero‐order kinetics on ethanol production and glucose utilization was evident.
s‐Triazole systems. Part IV: Novel substituted thio‐s‐triazole derivatives
Authors: Awad Ibrahim M. A. , Bakhite Etify A. , Abdel‐Rahman Abdu E. 
Published: July 2010

AbstractInteraction of (3‐aryloxymethyl‐4‐phenyl‐striazol‐5‐yl)thioacethydraz‐ide (la‐c) with phenyl isocyanate and/or with methyl/phenyl isothiocyanate gave semicarbazides (2a‐c) and thiosemicarbazides (3a‐f) respectively. Cyclization of (3a‐f) yielded s‐triazoles (4a‐f). Compounds 4b,d,f were easily alkylated giving S‐substituted thio‐s‐triazoles (5a‐e). Furthermore, compounds 4b,d,f underwent a Mannich reaction to give the expected Mannich bases (6a‐f). All compounds were fully confirmed by elemental and spectral analyses and have been screened in vitro, for antimicrobial activity.
Designer enzyme and cell applications in industry and in environmental monitoring
Authors: Wiseman Alan 
Published: July 2010

AbstractRenewed world interest in enzyme biotechnological industries now derives from the expectation that many new biocatalysts will be created by genetic engineering associated with protein engineering designer techniques, or by chemical modification of existing enzymes by use of protein tailoring methods. The biocatalysts produced are mainly enzymes, abzymes (catalytic antibodies) and synthesis (synthetic analogues or mimics), and these will be used in industry, synthesis, therapy: and in bioanalysis of components of foodstuffs, and the environment including water, air and soil. The biocatalysts, including whole cells, are firstly incorporated into a particular bioreactor form by use of enzyme engineering techniques such as immobilization, and are then used, as appropriate, to modify their substrates. Improved processing or enhanced products are thereby achieved in the case of manufacturing industry: or monitoring signals are generated, often in the form of a measurable change in current flow, in the case of environmental biosensors. Designer enzymes and cells can be made now for identified applications where the presently available biocatalysts are inadequate, incompatible or uncompetitive.
Temperature effects on polyphenol oxidase activity in organic solvents with low water content
Authors: Estrada P. , Baroto W. , Castillon M. P. , Acebal C. , Arche Late R. 
Published: July 2010

AbstractThe effect of temperature studies on polyphenol oxidase immobilized on glass beads were carried out in organic solvents. The optimum temperature for catalysis depended on the solvent and varied in a range from 26°C for dichloromethane to 50°C for toluene, benzene and 1,1,1‐trichloroethane. Optimum temperature and activation energy were independent of the water content of the system whereas the inactivation energies decreased as the water content of the system was decreased. The enzyme was stable in toluene up to 50°C although residual activity depended on the water content of the system. Thermoinactivation of polyphenol oxidase in toluene gave an activation energy for enzyme decay of 111.5 kcal mol−1 which is consistent with a conformational process. Among the agents employed to protect the enzyme against thermal denaturation 1 % (w/v) short‐chain polyols added to the buffer and 0.5 mmol dm−3 p‐nitrophenol added to toluene more than doubled the half‐life of the enzyme.
Biodegradation of phenol: A comparative study with and without applying magnetic fields
Authors: Jung J. , Sanji B. , Godbole S. , Sofer S. 
Published: July 2010

AbstractThe objective of this work was to study the effect of magnetic fields on the rate of phenol biodegradation using immobilized activated sludge. A recirculation flow bioreactor employing immobilized bacterial beads was used with phenol as the substrate to study the biodegradation process. This study was conducted by applying separately the north pole and the south pole magnetic fields to the bioreactor. Rate of dissolved oxygen consumption, phenol concentration and extracellular protein concentration were the parameters monitored during the process.It was observed that by applying a magnetic south pole to the process, biodegradation in the form of biological oxidation was enhanced. A 30% increase in biodegradation rate was obtained by applying a magnetic south pole of strength of 0.45 Tesla to the bioreactor with immobilized microbial beads as compared to the control. Magnetic north pole irradiation inhibited this type of biooxidation. This process has potential for biological treatment of organic wastes.
A comparison of adsorption characteristics of various activated carbons
Authors: Gergova K. , Petrov N. , Minkova V. 
Published: July 2010

AbstractThe physico‐chemical characteristics of activated carbons obtained from different agricultural by‐products by pyrolysis in a stream of water vapor have been investigated. It was established that under the same conditions of treatment the physico‐chemical and adsorption characteristics of activated carbons depend on the composition of the initial raw materials. Activated carbon obtained from apricot stones has the best properties. It is characterized by a large specific surface area and micropores volume and high iodine and methylene blue adsorption activity. The activated carbons produced from cherry stones and grape seeds are characterized by predominating meso‐ and macropores structure. It can be supposed this is related to the larger content of lignin in those materials.
Maximizing the production of acetone—butanol in an alginate bead fluidized bed reactor using clostridium acetobutylicum
Authors: Mollah Abdul H. , Stuckey David C. 
Published: July 2010

AbstractLow volumetric solvent productivities are one of the characteristics of an acetone‐butanol fermentation by C. acetobutylicum. A calcium alginate immobilized continuous culture was used in a novel gas‐sparged reactor to strip the solvents from the aqueous phase and reduce their toxicity. A dilution rate of 0.07 h−1 was found to give maximum solvent productivity at 0.58 g dm−3 h−1, although at 0.12 h−1 the productivity was slightly lower. In order to increase glucose uptake by the culture, feed glucose concentrations were increased over time to attempt to acclimatize the culture. This resulted in a productivity as high as 0.72 g dm−3 h−1 although this production rate was found to be unstable.