bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dehydrochlorination of propylene chlorohydrin with sodium hydroxide and with catholyte
Authors: Milchert Eugeniusz , Goc Waldemar , Meissner Egbert , Myszkowski Jerzy 
Published: May 2005

AbstractDehydrochlorination of an aqueous solution of propylene chlorohydrin with sodium hydroxide (12·5 and 30% by weight), with catholyte (5 or 10% by weight NaOH + 14% by weight NaCl) and with milk of lime (15% by weight) were compared. The use of catholyte (10% by weight NaOH + 14% by weight NaCl) enables propylene oxide to be obtained in a yield of 94·3%, with 100% conversion of chlorohydrin. The concentration of 1,2‐propylene glycol in the waste is 0·07% by weight.
Estimation of true biomass energetic yield and maintenance coefficient with errors in the variables
Authors: Solomon Bamidele O. , Erickson Larry E. , Yang Shie‐Shien , Posten Clemens , Deckwer Wolf‐Dieter 
Published: May 2005

AbstractSimple regression analysis is based on the least square of residual errors. To use this method, an independent variable which is observable without error is assumed to exist. For most analyses, the assumption is normally made without realising the implications. The present study demonstrates how parameters may be estimated with the assumption of error in all measurements. Data sets involving batch/fed‐batch cultivation ofCandida utiliswere analysed using a statistical approach with error in variables for the estimation of true biomass energetic yield and maintenance coefficient. This approach requires replicated measurements. For linear systems, such as in chemical/biochemical processes, replicated measurements are sometimes possible or there are physical/physiological reasons to group the observations into clusters. When clusters of replicated measurements are not available, the cluster analysis technique may be used to identify groups of near‐replicated data points. The procedure yielded similar results to those obtained by the ordinary least squares procedure for consistent data. However, for data of poor quality (especially data with large errors in the independent variable), the disparity between the two procedures was more significant.
Characterization of the intermediate product of coal solubilization by Penicillium simplicissimum
Authors: Achi Ome K. 
Published: May 2005

AbstractPenicillium simplicissimum has previously been shown to solubilize pre‐oxidized alkali‐extracted sub‐bituminous coal. The product of solubilization, a soluble acid‐precipitable coal polymer, was isolated and characterized. The effects of oxidation pretreatments on the ability to solubilize coal were also examined. The intermediate product, which comprised 30% of the original coal, was readily recovered from the growth medium by acid precipitation and possibly consisted of a heterogeneous mixture of high‐molecular‐weight compounds of approximately 2·7 × 104 molecular weight. Further characterization by elemental analyses revealed that the bioproduct was enriched in inorganic materials, oxygen, nitrogen but lower in carbon, hydrogen and sulphur when compared with the original coal. A 14% loss of carbon atoms occurred during the biodegradation. The product had a featureless visible light spectrum and a shoulder in the ultraviolet range at 290 nm. Infrared analyses showed a decrease in aromatic carbons, methylenic bonds and etheric oxygen. Experimental results suggested that solubilization changes appear to be largely oxidative and may involve cleavage of intermonomeric linkages in coal.
Micromixing and the steady‐state performance of bioreactors using recombinant bacteria—analysis through a reversed two‐environment model
Authors: Patnaik Pratap R. 
Published: May 2005

AbstractA reversed two‐environment model has been to study micromixing in continuous fermentation for growth and product formation by recombinant bacteria. As an example, an Escherichia coli M72 strain harbouring the plasmid pPLc23trpA1 and producing tryptophan synthetase is considered. With excess substrate, 10% plasmid‐free bacteria in the initial broth do not affect the steady‐state concentrations of plasmid‐containing bacteria but their mass fractions decrease significantly. With a smaller substrate concentration, the mass fractions decrease sharply as the dilution rate increases if micromixing is good; but concentrations still remain high. There is also a clear demarcation between regions of good and poor micromixing. These results are explained and an optimal combination of micromixing and dilution rate is suggested to maximise productivity.
Azo disperse dyes for synthetic fibres. I: 2‐Methyl‐ and 2‐phenylquinazolone derivatives
Authors: Fadda A. A. , Etman H. A. , Amer F. A. , Barghout M. , Mohamed Kh. S. 
Published: May 2005

AbstractTen variously substituted derivatives (IVa–j) of 4′(quinazol‐4‐on‐3‐yl) azobenzene were prepared. The effects of the nature and orientation of the substituents on the colour and dyeing properties of these dyes on polyester and acrylic fibres were evaluated.
Recovery of chromium from tannery effluents using a redox–adsorption approach
Authors: O'Dwyer Thomas F. , Hodnett Benjamin K. 
Published: May 2005

AbstractAdsorption isotherms for sodium and trivalent chromium uptake from aqueous solutions onto Amberlite resin were prepared at 18°C. Adsorption of each cation followed the Langmuir model. The rate of uptake of each cation was found to be film diffusion controlled with sodium showing the most rapid uptake. In aqueous solutions containing both chromium and sodium as the only cationic species, it was found that with increasing initial concentration of sodium, the trivalent chromium uptake on the resin decreased substantially. To overcome this difficulty a four step redox–adsorption system has been developed for the removal of Cr3+ from tannery effluents. The first step comprises the oxidation of trivalent chromium to the hexavalent form using selected common oxidising agents. The liquid effluent is then passed through an Amberlite cation‐exchange resin in step 2 where the sodium in the waste stream is completely removed. The anionic hexavalent form of chromium (Cr2O) passes unaltered through the resin along with the waste stream. In the third stage the dichromate is reduced back to the trivalent cationic form which is subsequently removed from the waste stream by a second Amberlite ion‐exchange bed in stage 4. Each step in this process is assessed in batch and flow mode using simulated and real tannery effluents.
Ethanol production by alginate immobilised yeast in a fluidised bed bioreactor
Authors: Gilson Christopher D. , Thomas Adrian 
Published: May 2005

AbstractYeast, immobilised in alginate beads of known standard size and mechanical strength, has been utilised in a novel design of fluidised bed bioreactor which avoids problems of particle flotation and gas logging. Circulating substrate simultaneously entered the top and bottom of the bed. The bioreactor operated reliably for periods of up to 20 days. Increasing alginate concentration in the range 1–5% (w/w) had little effect on the performance of the immobilised yeast in converting ethanol to glucose but reduced the tendency of beads to split. Increasing bead diameter in the range 1–5 mm increased the tendency to split and reduced overall conversion of glucose. A model was developed to describe the consumption of glucose within beads based on Michaelis–Menten kinetics and the diffusion of glucose into beads. Application of the model to experimental results showed maximum reaction velocity to be independent of bead diameter and alginate concentration. The model confirmed that the observed reduction in ethanol yield compared with free yeast cells was caused by the lower substrate concentration towards the centre of the bead as opposed to any change in the metabolic rate of the immobilised cells.
Separation of di‐ and tripeptides with solvent extraction and an emulsion liquid membrane
Authors: Hano Tadashi , Matsumoto Michiaki , Kawazu Takahisa , Ohtake Takaaki 
Published: May 2005

AbstractThe extraction equilibria of various di‐ and tripeptides with di‐2‐ethylhexylphosphoric acid (D2EHPA) were studied at low pH values. The complex extracted to organic phase consisted of one molecule of peptide and two molecules of D2EHPA dimer. The extraction constants of the peptides correlated well with the distribution coefficients of peptides between 1‐octanol and water, which is a measure of hydrophobicity. The permeation rates of peptides through an emulsion liquid membrane were examined by using D2EHPA as a carrier, Span 80 as an emulsifier and kerosene as a diluent. The rates varied considerably with peptide type, depending upon the hydrophobicity.
Synthesis and evaluation of alkyl fumarate–vinyl acetate copolymers in combination with alkyl acrylates as flow improvers for Borholla crude oil
Authors: Borthakur Arun , Laskar Narayan C. , Mazumdar Ranjit K. , Rao Kosuru V. , Subrahmanyam Bulusu 
Published: May 2005

AbstractA number of alkyl fumarate–vinyl acetate copolymers were prepared and evaluated as flow improvers for high waxy Borholla crude oil. Alkyl fumarate–vinyl acetate copolymers having 19·2 as the average carbon number of the alkyl group in combination with polybehenyl acrylate were found to show optimum activity. Alkyl fumarate–vinyl acetate copolymers reduce the pour point, plastic viscosity and yield stress considerably and polybehenyl acrylate prevents the crude oil from attaining the gel structure on prolonged storage.
Synthesis of linear alkylbenzene in a liquid–solid circulating fluidized bed reactor
Authors: Liang Wugeng , Yu Zhiqing , Jin Yong , Wang Zhanwen , Wang Yao , He Mingyuan , Min Enze 
Published: May 2005

AbstractThe alkylation reaction of benzene with 1‐dodecene was investigated in a liquid–solid circulating fluidized bed reactor (LSCFBR) using HY zeolite as catalyst. The conversion of 1‐dodecene, the apparent reaction rate constant, the activity of catalyst and the product distribution in the LSCFBR were analysed and compared with the values obtained using a stirred tank batch reactor (STBR).
Influence of power input and aeration method on mass transfer in a laboratory animal cell culture vessel
Authors: Moreira José L. , Cruz Pedro E. , Santana Paula C. , Feliciano Ana S. , Lehmann Jurgen , Carrondo Manuel J. T. 
Published: May 2005

AbstractLarge‐scale animal cell operation is costly both in terms of facilities and consumables. Hence developmental studies with animal cells normally start at laboratory scale, often using small stirred tanks. In order to better optimise cell performance, it is necessary to know the physical conditions under which the cells are grown. In this study a laboratory‐scale vessel (2 dm3 working volume) with two large‐bladed paddle impellers was characterised hydrodynamically. Three different aeration methods (surface, sparging and membrane aeration) were investigated and compared. Power input and oxygen transfer rates to culture medium were determined as a function of agitation and gas flow rates. Non‐dimensional correlations were established for each case, which can be useful for scale‐up purposes. The results obtained indicate that power input is quite dependent on the vessel accessories: for the same agitation rate, the maximum power is required for the membrane structure and the minimum for surface aeration, with the addition of the sparger leading to an intermediate situation. Predictions found in the literature can be used for simple vessels, but may not be applicable when accessories are added to the vessel structure; in such cases, the use of experimental relationships are required. Oxygen transfer rate was dependent on the aeration method and working conditions (agitation and gas flow rates), particularly for sparger aeration. Membrane aeration gave larger oxygen transfer but higher gas pressure and flow rates were required. Surface aeration was the least effective method, nevertheless requiring gas flow rates similar to those used for membrane aeration. The aeration method of choice depends upon the culture and work specificities: surface aeration is limited to small cell concentrations and low oxygen consumption rates. For higher cell concentrations and oxygen consumption rates, both membrane and sparger aeration methods can be applied: the use of the sparger is limited to cells that are not affected by the presence of bubbles or the addition of surfactants, whereas the membrane aeration basket should not be used when a hydrodynamically controlled stirred tank is required.
Metal sorption with extractant‐impregnated macroporous resins. 1. Particle diffusion kinetics
Authors: Juang Ruey‐Shin , Lin Horng‐Chyuan 
Published: May 2005

AbstractKinetic measurements were made for the sorption of copper ions from aqueous sulfate solutions with di(2‐ethylhexyl)phosphoric acid‐impregnated Amberlite XAD macroporous resins in finite bath by a batch‐contact time method. The sorption process of copper was first determined to be controlled by particle diffusion using a modified shrinking‐core mechanism, which considered reversibility of the sorption. A more rigorous model based on Fick's law was then applied to justify the applicability of the modified shrinking‐core model to the present sorption systems. The effective particle diffusivity had an order of 10−12 (in m2 s−1), which was in agreement with those obtained for chelating ion‐exchange processes.
Composition and interfacial activity of hydrophobic sulphide‐type extractants
Authors: Dziwiński Euzebiusz , Cote Gerard , Bauer Denise , Szymanowski Jan 
Published: May 2005

AbstractThe composition and interfacial activity of dihexyl sulphide (Elf), dodecyl methyl sulphide (two samples from Elf and Penwalt) and n‐dodecyl hydroxyethyl sulphide (Elf) which are commercially available sulphide‐type extractants have been investigated. Recrystallized n‐dodecyl hydroxyethyl sulphide was found to be of high purity (i.e. impurities, if any, are below the detection level of a gas chromatograph equipped with an efficient capillary column), whereas it was shown that all the other sulphides contained many components which were separated and, for most of them, indentified by a GC/MS technique. Recrystallized n‐dodecyl hydroxyethyl sulphide starts to adsorb at the 2 M HCI/dodecane interface at concentrations (typically 10−3 M) of about one order of magnitude lower than dodecyl methyl sulphide (Elf or Penwalt). Dihexyl sulphide exhibits a very weak interfacial activity and the observed decrease in the interfacial tension in the system containing about 0·4 M dihexyl sulphide cannot be attributed with certainty to its own interfacial activity.
Complexation behavior of proteins with polyelectrolytes and random acrylic polyampholytes using turbidimetric titration
Authors: Nath Sunil 
Published: May 2005

AbstractThe complexation behavior of proteins with dilute solutions of a polyelectrolyte (polyacrylic acid) and a random acrylic polyampholyte composed of acrylic acid, dimethylaminoethyl methacrylate and methyl methacrylate was experimentally investigated using turbidimetric titration. The random polyampholyte had a number‐average molecular weight of 70,000 and a polydispersity index of only 1·3. Polyampholyte–polyampholyte interaction (self‐aggregation) and polyampholyte–protein complexation behavior was studied as a function of pH (3–9) and polymer dosage (50–400, 5000 mg polymer per g protein). Large increases in turbidity (>500%) were observed for protein–polyampholyte mixtures (compared with polyampholyte alone). However, protein analysis of the supernatant and precipitate after centrifugation revealed that only about 10% of the protein precipitated with the random polyampholyte while 90% of the protein remained in the equilibrium liquid. This implies that a very small degree of protein–polymer interaction can lead to unusually large increases in turbidity. Experiments with a single polyelectrolyte (polyacrylic acid) and oppositely‐charged protein showed the opposite trend with 90% precipitation of protein. Hence, great care needs to be taken in interpretation of turbidimetric titration data.
Friction on a solid sphere exposed to gas–liquid and gas–liquid–solid flow in bubble column and fluidized bed reactors
Authors: Essadki H. , Delmas H. , Svendsen H. F. 
Published: May 2005

AbstractLocal velocity gradients on a solid spherical surface have been studied in a bubble column and in two‐ and three‐phase fluidized beds, in order to clarify the influence of gas flow. The electrochemical method, measuring apparent local mass transfer coefficients, was verified and used to obtain the local velocity gradients, shear stresses and total frictional forces. The observed mass transfer rate was independent of liquid velocity, owing to a non‐changing flow structure around the particles and not to averaging opposing effects. The identity in flow structure also held for three‐phase fluidized beds up to a superficial gas velocity of 5 cm s−1. The dramatic increase in velocity gradient on gas introduction was not a result of decreased homogenous density, but was caused by a change in the turbulent structure around a particle, leaving a larger portion of the total drag as frictional drag, thus improving the mass transfer characteristics of the bed. Use of velocity gradient measurements, including span of fluctuations and exposure time, to predict biomass growth and mechanical degradation in a reactor is also discussed.
Clean technology—an introduction
Authors: Clift Roland 
Published: May 2005

AbstractA Clean Technology is a means of providing a human benefit which, overall, uses less resources and causes less environmental damage than alternative means with which it is economically competitive. Life Cycle Assessment is central to Clean Technology, as the way to identify overall resource usage and environmental damage. Pollution Prevention and Waste Minimisation are important parts of Clean Technology, but more fundamental is the shift from selling products to providing services. Some specific technological challenges for the chemical and biotechnology industries are identified.
Homogeneous and heterogeneous catalytic reactions in a cobalt oxide/graphite air electrode. Part IV. Mechanistic studies on a ring‐disk carbon electrode in alkaline solution
Authors: Yang Y. , Tseung A. C. C. , Lin Z. G. 
Published: May 2005

AbstractThe redox properties of HCoO on a glassy carbon electrode in the absence and presence of hydrogen peroxide have been investigated by using cyclic voltammetry and UV‐Vis spectroscopy in alkaline solution. Corresponding rotating ring‐disk experiments showed that the disk current increased by about 60% in the presence of HCoO, confirming the important role played by HCoO in the homogeneous decomposition of hydrogen peroxide.
Recovery of vanadium and nickel in fly ash from heavy oil
Authors: Akita Shigendo , Maeda Tsuyoshi , Takeuchi Hiroshi 
Published: May 2005

AbstractRecovery of vanadium and nickel from an oil fly ash is studied in a two‐step leaching process, carried out under ambient pressure without calcination. In the leaching, nickel is dissolved with NH4Cl in the first step, followed by vanadium leaching with Na2CO3 in the second step. Both leachants depress the dissolution of iron and aluminium from the ash and hence the selective leachings are feasible. Nickel was recovered in 87% yield from the leach liquor by precipitation with Na2S, the purity of NiS being over 99% on the basis of the target metals (V, Ni, Fe, Al and Mg). For the recovery of vanadium, which has a relatively low concentration in the leach liquor, solvent extraction with TOA is preferable to concentration, prior to crystallization with NH4Cl. The experimental data showed that the vanadium concentration of the stripping solution is increased by about 15 times that of the leach liquor, which results in 78% yield as NH4VO3 crystals.
Gas‐Sparged bioreactors for CO2 fixation by Dunaliella tertiolecta
Authors: Suzuki Takahiro , Matsuo Takeshi , Ohtaguchi Kazuhisa , Koide Kozo 
Published: May 2005

AbstractTwo kinds of bioreactors, a bubble‐column and an air‐lift bioreactor, have been designed. The influence of operating conditions such as medium composition, light intensity, carbon dioxide concentration in the flushing gas, culture temperature, and gas flow rate, on photosynthesis of Dunaliella tertiolecta were studied using a chemometrics approach. The bubble‐column bioreactor system was shown to be advantageous over the air‐life because of a weaker intensity of hydrodynamic stress derived from gas bubble dispersion and culture broth mixing. Optimal conditions for carbon dioxide fixation or maximal growth rate were determined. The effect of hydrodynamic shear forces on the algal wall produced by gas bubbling was identified as one of the most significant factors for algal growth.
Measurement of bound water content in sludge: The use of differential scanning calorimetry (DSC)
Authors: Lee Duu‐Jong , Lee Sun F. 
Published: May 2005

AbstractThe bound water content of original and frozen activated sludge and an inorganic sludge were measured via differential scanning calorimetry (DSC) and drying tests. Original sludge contained a significant level of bound water which was reduced by about 50% after freeze/thaw treatment. A simple thermodynamic interpretation showed that liquid–solid binding strength played an important role in depression of the freezing point of bound water in a sludge. The choice of a threshold temperature in a DSC test was equivalent to definition of a threshold binding strength dividing bound/non‐bound water content. The possible close relationship between the bound water content measured via DSC and the drying test is discussed. The importance for sample uniformity was also examined.
Transferrin metalloprotein affinity metal chromatography
Authors: Spires Kevin , Vincent John B. 
Published: May 2005

AbstractThe metal transport protein transferrin, when immobilized to Sepharose, can serve as an affinity media for the selective removal and subsequent release of heavy metal ions from aqueous solution. The material is stable over the pH range of 2–10, is self‐indicating for the binding of certain metal ions, and maintains its integrity towards metal‐binding capacity for long periods of time. In one step heavy metal ion concentrations can be reduced by at least five orders of magnitude to, at most, part per billion levels. The findings here presented suggest a novel practical method for the decontamination and/or recovery of metals ions from very dilute solutions and represent the first efforts to extend the concept of affinity chromatography to metal ions.
Claisen–Schmidt reaction in a hydrotropic medium
Authors: Sadvilkar Vikas G. , Samant Srinivas D. , Gaikar Vilas G. 
Published: May 2005

AbstractThe Claisen–Schmidt condensation of benzaldehydes with acetophenones was carried out in an aqueous medium using sodium butylmonoglycolsulfate (NaBMGS) and sodium salts of aromatic sulfonic acids as hydrotropes. Substantial enhancement in the rate of the reaction was obtained, along with the easy recovery of the product. Recycling of the hydrotrope solutions has been tested without any loss in the rate of the reaction.