bluuebunny/crossref_metadata_2025_split huggingface dataset:
Production of astaxanthin by Phaffia rhodozyma using peat hydrolysates as substrate
Authors: Martin Antonio M. , Acheampong Edward , Patel Thakor R. 
Published: July 2010

AbstractPeat hydrolysates prepared with and without acid and under various temperatures were tested in the growth of the yeast Phaffia rhodozyma ATCC 24202, which synthesizes carotenoids, including astaxanthin. The hydrolysate that resulted in the best growth of P. rhodozyma biomass was subsequently used as substrate for the submerged culture of the yeast, and the growth conditions were optimized. Those studied included initial substrate concentration, initial pH, incubation temperature, fermentation time and agitation rate. The optimum growth conditions produced approximately 4.6 g dm−3 of dry biomass with a crude protein content of 47% (dry weight basis). The mean astaxanthin content of the yeast cultivated under these conditions, 1567 μg g−1 dry yeast, was also the highest produced in this work, and compares favourably with other results reported in the literature.
Equilibrium studies of the extraction of zirconium(IV) from sulfuric acid solutions with Di(2‐ethylhexyl)phosphoric acid
Authors: Juang Ruey‐Shin , Lo Ru‐Huey 
Published: July 2010

AbstractEquilibrium studies were made at 25°C in the extraction of zirconium(IV) from sulfuric acid solutions with di(2‐ethylhexyl)phosphoric acid (D2EHPA, HR) dissolved in kerosene. The reaction stoichiometry was numerically determined and the compositions of the extracted species were found to be ZrR4 and ZrR4(HR) at low loading ratios of D2EHPA (α < 0.09), but became ZrR4 and ZrR4(HR)3 at relatively higher loading ratios (0.10 < α < 0.32). The equilibrium constants for the formation of these species were also obtained. Furthermore, numerical treatment of the experimental data excluded the existence of polynuclear complexes under the conditions studied (α < 0.32).
Synthesis and surface activity of amine‐type surfactants containing fluorocarbon hydrophobes
Authors: Meissner Egbert , Myszkowski Jerzy , Szymanowski Jan , Blaszczak Jan 
Published: July 2010

AbstractAmine‐type surfactants containing fluorocarbon hydrophobes were synthesized and used to study their adsorption at water/air interfaces. They exhibit a high surface activity and decrease both effectively and efficiently the surface tension of their aqueous solutions. They are able to decrease the surface tension to about 20 mN m−1.
Covalent immobilization of Aspergillus niger on pHEMA membrane: Application to continuous flow reactors
Authors: Arica M. Yakup , Sharif Fadel A. , Alaeddinoǧlu Ngürdal , Hasirci Nesrin , Hasirci Vasif 
Published: July 2010

AbstractPoly(2‐hydroxyethyl methacrylate) (pHEMA) membrane was prepared via photopolymerization and activated with epichlorohydrin. The conidia of Aspergillus niger strains (wild type ‘NRRL‐3’ and genetically improved strain ‘NRRL‐3/2‐2A’) were covalently‐immobilized on the membranes. Uniform growth of A. niger cells on membrane surfaces was verified by SEM. The glucose oxidase (GOD) activity of the immobilized cells was determined in a continuous flow membrane reactor (CFMR) by assaying for hydrogen peroxide produced. The activity was also determined in the culture fluids of A. niger strains, freely grown in batch cultures. The CFMR was run with 0.1 mol dm−3 glucose with a fixed flow rate of 20 cm3 h−1 for 60 h during which a 10% loss of the original activity was detected. The loss of the activity with the freely cultivated mycelia was about 50% after 30 h. The GOD activity of the improved strain NRRL‐3/2‐2A was about 20 times higher whether in immobilized or in free form. The GOD activity of the immobilized A. niger strains in the continuous flow membrane reactor was found to be 2.5 times better than their counterparts freely grown in batch cultures indicating that immobilization increases the activity and the stability of the microorganisms.
Immobilization of glucose oxidase: A comparison of entrapment and covalent bonding
Authors: Arica M. Yakup , Hasirci Vasif 
Published: July 2010

AbstractGlucose oxidase was immobilized onto poly(2‐hydroxyethyl methacrylate) (pHEMA) membranes by two methods: by covalent bonding through epichlorohydrin and by entrapment between pHEMA membranes. The highest immobilization efficiency was found to be 17.4% and 93.7% for the covalent bonding and entrapment, respectively. The Km values were 5.9 mmol dm−3, 8.8 mmol dm−3 and 12.4 mmol dm−3 for free, bound and entrapped enzyme, respectively. The Vmax values were 0.071 mmol dm−3 min−1, 0.067 mmol dm−3 min−1 and 0.056 mmol dm−3 min−1 for free, bound and entrapped enzyme. When the medium was saturated with oxygen, Km was not significantly altered but Vmax was. The optimum pH values for the free, covalently‐bound and entrapped enzyme were determined to be 5, 6, and 7, respectively. The optimum temperature was 30°C for free or covalently‐bound enzyme but 35°C for entrapped enzyme. The deactivation constant for bound enzyme was determined as 1.7 × 10−4 min−1 and 6.9 × 10−4 min−1 for the entrapped enzyme.
Adsorbents for the recovery of aroma compounds in fermentation processes
Authors: Krings Ulrich , Kelch Markus , Berger Ralf G. 
Published: July 2010

AbstractUsing a model solution of 12 aroma compounds, representative of microbial volatiles, 31 different adsorptive materials were investigated with regard to their solid phase extraction and desorption properties. Well known styrene—divinylbenzene‐based resins and alternative adsorbents including zeolites, β‐cyclodextrin and modified activated carbon were compared. Adsorption/desorption rates in aqueous solution were determined for each adsorbent. Isotherms and adsorption kinetics were determined for the most effective adsorbents.
Photocatalytic properties of CdS and CdS—ZnS mixtures incorporated into the interlayer of layered compounds
Authors: Sato Tsugio , Masaki Katsuhiko , Yoshioka Toshiaki , Okuwaki Akitsugu 
Published: July 2010

AbstractSemiconductor particles composed of CdS and mixed CdS—ZnS were incorporated into the interlayers of layered compounds such as H4Nb6O17, H2Ti4O9, montmorillonite and layered double hydroxides, [M(II)1‐xM(III)x(OH)2](CO3)x/2.nH2O(M(II) = Mg2+, Zn2+, M(III) = Al3+, x = 0.33), by the chemical reactions between S2‐ and Cd2+—Zn2+ and/or Cd(edta)2‐—Zn(edta)2‐ in the interlayers. The incorporated particles seemed to be very small, less than 1 nm thick. The band gap energies of CdS and CdS‐ZnS mixtures in the interlayer were significantly larger than those of normal‐crystalline ones. The CdS‐ZnS mixtures incorporated into the interlayers were capable of efficient hydrogen evolution following irradiation with visible light in the presence of Na2S, Na2SO3 and/or 2‐aminoethanol as a sacrificial donor. The hydrogen production activities of the CdS—ZnS mixtures incorporated into the interlayers were superior to those of unsupported CdS—ZnS. The incorporation of the CdS—ZnS mixtures in the interlayer of a semiconductor such as H2Ti4O9 and H4Nb6O17 was much more efficient in enhancing the hydrogen production activity than when an insulator such as montmorillonite and layered double hydroxide was used.
Aeration and mixing in vortex fermenters
Authors: Chisti Yusuf , Moo‐Young Murray 
Published: July 2010

AbstractThe overall apparent volumetric gas—liquid mass transfer coefficient (k95a) and the mixing time (t95) were determined in a 240 dm3 vortex aerated fermenter over stirrer speed and air flow ranges of 300–800 rpm and 10–45 normal dm3 min−1, respectively. The mass transfer data obtained in an aqueous salt solution (2.5 kg m−3 NaCl in water) compared well with the measurements in a fermentation medium used in culture of certain microaerophilic bacteria. Over the ranges examined, the gas‐liquid mass transfer coefficient depended only on air flow rate; the dependence was linear with flow. Mixing time declined with increasing agitation according to a power‐law relationship. The mixing and mass transfer characteristics of the vortex aerated system were compared with that of a ‘standard’ stirred tank fermenter (27 dm3). The mixing time variations with respect to agitation rate were remarkably similar for the two types of fermenters examined.
A novel approach to the photostabilisation of spironaphthoxazines
Authors: Oda Hironori 
Published: July 2010

AbstractPhotochromic spironaphthoxazines are given considerable attention as functional dyes for reversible image‐recording media. Numerous potential metal complexes were synthesised to prolong the life of coloured species. The protecting effect of these compounds towards the decolorisation reaction in the dark or photofading of photocoloured species was examined on cellulose. It was found that the zinc or nickel salt of 2‐hydroxycarbazole‐1‐carboxylic acid is very effective for stabilising the coloured form of spironaphthoxazine.
Characteristic volumes and properties of surfactants
Authors: McGowan John C. , Sowada Rudolf 
Published: July 2010

AbstractAn equation which has been used for the estimation of solubilities of organic liquids in water has been adapted for the study of critical micelle concentrations (CM) of surfactants. The quantities used for the estimation of CM are the characteristic volume, number and degree of hydration and the concentration in the micelles of the surfactant.
Potentiometric determination of ephedrine hydrochloride using plastic membrane ion‐selective electrode
Authors: Zareh M. M. , Issa Y. M. , Shoukry A. F. , Shohaib R. E. 
Published: July 2010

AbstractA plastic membrane electrode based on phenylephrine‐tetraphenylborate ion association shows a Nernstian response to both ephedrinium (Ep+) and silver (Ag+) cations over the concentration ranges 2x10−5—10−1M and 10−5—10−1M for Ep+ and Ag+, respectively. The performance characteristics of the electrode were investigated. The electrode proved to be an excellent potentiometric sensor for the determination of Ep‐hydrochloride in its pure solutions and pharmaceutical preparations using the extrapolation method and potentiometric titration using a standard solution of AgNO3.
Synthesis of some novel 2(1H)‐quinazolinones and 2‐thioxo analogues from newly synthesised 1‐acyl‐3‐alkoxyphenylureas and thioureas
Authors: Jaeda Mousa I. , Abdel‐Samii Zakaria K. , Britten A. Z. 
Published: July 2010

AbstractA convenient route for the synthesis of new 2(1H)‐quinazolinones (IIc—h) and 2(1H)‐quinazolinethiones (IIi—j) is discussed. It involves the cyclodehydration of 1‐acyl‐3‐(alkoxyphenyl)ureas (Ic—h) and the corresponding thioureas (Ii—j) in polyphosphoric acid. Elucidation of structures of the isolated products have been proved in the light of their elemental analysis and spectroscopic data.
The osmometry of high polymers. II. Some consequences of comparing osmotic with other measurements
Authors: Cleverdon D. , Laker D. 
Published: July 2010

AbstractExperiments with polystyrene are described (a) to illustrate the difference between viscosity‐average and number‐average differential distribution curves and (b) to test the nature and the efficiency of the fractionation process. The viscosity‐molecular weight relationship for dilute solutions of high polymers is critically reviewed. Evidence is presented which suggests that during fractionation successive fractions have differing distributions. This indicates a lack of precision in the evaluation of the andKof the Houwink equation, and the absence of objectivity in the method of plotting differential distribution curvesviatheir stepwise and integral curves.
Time for passage of material through rotary kilns
Authors: Pickering R. W. , Feakes F. , Fitzgerald M. L. 
Published: July 2010

AbstractAn expression is developed for the passage of material through rotating cylindrical kilns or driers, relating the time of passage to the other important variables—slope, length, diameter, and rate of rotation of the kiln, feed rate and rill angle of the material. The expression is derived from fundamentals, and is in accord with previously published empirical relations. It is thought that the derivation will promote a better understanding of the mechanism of the movement of materials in rotary kilns and driers.
Heat‐transfer coefficient of condensing vapours
Authors: Chu Ju Chin , Dmytryszyn M. , Tichy W. , Kubik K. C. , Smith O. L. 
Published: July 2010

AbstractThe original method employed by Wilson to eliminate the use of thermocouples embedded in the tube wall in evaluating the heat‐transfer coefficient of the condensing vapours is not fundamentally sound. A modified method on a more rigorous basis is presented.It has been demonstrated theoretically that the heat‐transfer coefficient of a condensing vapour is a function of rate of heat only. The proposed method consists in varying the rate of flow of cooling water inside the condensing tube and the over‐all temperature difference to obtain the heat‐transfer coefficients at a constant rate of heat‐transfer. The over‐all temperature drop is varied by changing the pressure in the vapour space. The film coefficient is then calculated from the intercept of a plot of δ T/q against 1/(1 + 0.011t) V0.8.The heat‐transfer coefficients of trichloroethylene, bromobenzene, nitromethane and n‐hexyl alcohol have been experimentally determined by the proposed method. The theory of the method was confirmed by plotting h0 against q; the slope was equal to‐1/3.The heat‐transfer coefficients predicted from Nusselt's equation agreed with those determined experimentally for trichloroethylene and bromobenzene, but not with those for nitromethane and n‐hexyl alcohol.
Preparation of the polyaminoguanidines
Authors: O'Connor T. E. , Horgan K. , Reilly J. 
Published: July 2010

AbstractGuanylazide nitrate (I) interacts with hydrazine, the reaction products varying with molar ratio of hydrazine to azide. With equimolecular quantities of reactants, cyanamide, hydrazoic acid, 5‐amino‐tetrazole (III) and some aminoguanidine are formed, but with higher proportions of hydrazine, diaminoguanidine and triaminoguanidine are the chief products.Simple and rapid preparative methods for diaminoguanidine nitrate and triaminoguanidine nitrate are described.Benzylideneaminoguanidine, unlike aminoguanidine, does not undergo hydrazinolysis, but in a replacement reaction gives benzylideneazine and aminoguanidine.
The quantitative removal of corrosion products from zinc
Authors: Stroud E. G. 
Published: July 2010

AbstractIn order to estimate quantitatively the corrosion of zinc by the loss in weight of metal, corrosion products are removed by immersion of the corroded metal in a cold solution of 10% chromic anhydride to which is added 2% silver chromate and excess (more than 19%) strontium chromate, the whole being kept well stirred. The method, while permitting the removal of heavy deposits of corrosion product, prevents attack on the basis metal such as would be produced by chlorides and sulphates in the deposit in the presence of chromic acid.
Formation of metallic hydrides and nitrides and their significance in the synthesis of ammonia
Authors: Soliman A. 
Published: July 2010

AbstractAdsorption of nitrogen and hydrogen on lithium was investigated and the activation energy for nitrogen found to be 47 kg.‐cal./g.‐mol. The addition of other metals promoted adsorption, cerium being found the most effective. The rates of formation of calcium hydride and calcium nitride from the gases and the metal were found at first to increase with temperature up to a maximum and thereafter to decrease. The effect of high pressure on the rates of formation of hydrides and nitrides was also investigated. The possibility of synthesizing ammonia by passing nitrogen and hydrogen, alternately or in admixture, over these metals is discussed.
Routine measurement of surface of paint pigments and other fine powders. II
Authors: Carman P. C. , Malherbe P. Le R. 
Published: July 2010

AbstractThe present paper is intended to extend the data in Part I with respect (i) to comparison of the slip‐corrected air‐permeability method with other methods in the normal pigment range, i.e. above o.1 μ., and (ii) to the study of particles below o.1 μ. An absolute comparison is made by using glass microspheres of about 3 μ. diameter. In the case of particles below 0.1 μ., the permeability method remains valid, though formation of plugs in the normal porosity range becomes much more difficult, and, for the very finest particles, it is advisable to replace air by helium, owing to possibilities of adsorption and surface flow of adsorbed molecules.
Determination of lead as basic lead chromate and its application to the separation of lead from silver
Authors: Guthrie F. C. , Nance J. T. 
Published: July 2010

AbstractLead is quantitatively precipitated as basic lead chromate, PbO.PbCrO4, by addition of sufficient potassium chromate, followed by ammonia, to the boiling solution of the lead salt. If a silver salt is also present the silver chromate first formed dissolves in the excess of ammonia. After filtration the silver may be determined as bromide or titrated by a modified Volhard method.
Moisture permeability, diffusion and sorption in organic film‐forming materials
Authors: Thomas A. Morris 
Published: July 2010

AbstractExperimental results which have been obtained in the course of comprehensive investigations of the water‐vapour permeability, diffusion and sorption of organic film‐forming materials are summarized. These data are used for elucidating the mechanisms and inter‐relationships of the processes. The analysis is based on thermodynamic principles and the multimolecular theory of adsorption. It is shown that the moisture sorption/relative humidity curves agree with the B.E.T. (Brunauer, Emmett and Teller) adsorption equation up to about 90% R.H. The heat of sorption is found to be the same as the heat of liquefaction of free water. It is concluded that the moisture sorption is a result of hydrogen‐bond formation with hydrophilic radicals in the molecules of the solid plus van der Waals' forces. The number of adsorption sites per g. of solid is calculated. The entropies of sorption for the various materials are estimated to show the degree of order of the sorbed moisture as compared with ice.Diffusion constants are derived from sorption‐ and desorption‐rate curves; an anomaly in some of the sorption‐rate curves is discussed. The activation energies of diffusion indicate that, with one exception, diffusion is a process of repeated vaporization and sorption; the energy required for ‘hole’ formation is relatively low except with polyvinyl chloride (PVC). Fick's law of diffusion is not applicable at medium and high R.H.s; it is probable that the rate of permeation depends directly on the vapour‐pressure difference and not on the concentration gradient, but it appears that quantitative calculation of sorption and desorption rates by the classical diffusion equation is not very sensitive to appreciable deviations from Fick's law. The derivations of the B.E.T. equations for multimolecular adsorption and for the free energy of sorption are given as Appendices.
Studies in the corrosion of metals occasioned by aqueous solutions of some surface‐active agents. I. Copper
Authors: Holness H. , Ross T. K. 
Published: July 2010

AbstractThe action of dilute aqueous solutions of representative anionic, cationic and non‐ionic wetting agents on sheet copper has been studied. Three types of water have been used—London tap‐water, distilled water and tap‐water softened by the zeolite base‐exchange process. The effects of varying the pH of the solutions from 2 to 12 and of temperature changes have been investigated.Most of the anion‐active agents examined first coated the copper with a water‐repellent film which afforded protection to the metal with primary and secondary sodium alkyl sulphates and sodium alkyl aryl sulphonate, but not with sulphonated castor oil or triethanolamine lauryl sulphate. With the cationic agents no water‐repellent film was formed and only triethanolamine attacked the copper to any great extent. There was no obvious action with the non‐ionic agent.In general, rise of temperature caused increased attack, but changes in pH of the solutions were without marked effect on the course of the corrosion.All results have been expressed graphically and a mechanism is suggested.
The colorimetric determination of aluminium in water using ammonium aurin tricarboxylate
Authors: Rolfe A. C. , Russell F. R. , Wilkinson N. T. 
Published: July 2010

AbstractA method is described for the colorimetric determination of aluminium in water using ammonium aurin tricarboxylate at a controlled pH. Reaction of iron is inhibited by the addition of thioglycollic acid to form ferrous thioglycollate which is colourless at the pH of the test solution (4.4). The test is sensitive to 0.3 μg. aluminium and satisfactory results have been obtained over a range of 0–20 μg. Anions and cations in amounts normally present in water do not interfere, but some interference is obtained with excessive quantities. Hexametaphosphate and pyrophosphate interfere but these can be removed by hydrolysis to orthophosphate.The test can be applied to the analysis of various alkali products after conversion to sodium chloride if a calibration curve is prepared in the presence of the appropriate amount of sodium chloride.
The preparation of highly reactive chars from coal and their interaction with sulphur
Authors: Kramers W. J. 
Published: July 2010

AbstractThis paper describes the preparation from coal of carbonized briquettes which are highly reactive to sulphur and are promising as a substitute for wood charcoal in the manufacture of carbon disulphide. A description is given of the variables influencing the briquette carbonization process and the way in which they can be controlled to give products of very high reactivity. A comparison has been made of the rate of interaction of various carbons, including the chars, with sulphur and the results are discussed in relation to the factors influencing their reactivity.
Preparation of metals in a finely divided state for use as catalysts
Authors: De Kok W. J. C. , Waterman H. I. 
Published: July 2010

AbstractMetals and alloys, commonly used as catalysts, are prepared in a finely divided state by atomizing under pressure. The sprayed particles are activated by oxidation, e.g. with sodium hypochlorite solution, washed, dried and reduced with hydrogen.
Studies in acetylene flames. IV. Dangers associated with carbon monoxide produced from acetylene lamps in coal mines
Authors: Cumming A. P. C. , Horn J. A. 
Published: July 2010

AbstractThe present paper is an endeavour to interpret the experimental results (previously obtained by the present authors) from the point of view of safety in mines in which open acetylene lamps are used as the source of illumination. The danger caused by the formation of CO from acetylene lamps in isolated workings becomes distinctly serious when the oxygen content of the atmosphere falls to 17% or below. At this concentration of 17% oxygen, and operating with two acetylene lamps (2‐in. flames) in an isolated working of 1000‐cu. ft. capacity, the concentration of CO in the working could reach the value of 0.09% after a period of 8 hr. It is estimated that under these conditions the time of exposure required to cause death would be under 2 hr.Tables are provided which enable the concentration of CO in an atmosphere to be estimated under any particular conditions.
Observations on the inefficacy of a desiccator in determining the moisture in coal
Authors: Belcher R. , Mott R. A. 
Published: July 2010

AbstractDuring research on the indirect determination of moisture in coal, the authors examine the errors possible when using a desiccator, and study the relative values of various desiccants. They conclude that an ordinary desiccator, regardless of the efficiency of the desiccant it contains, is of little use in preventing absorption of moisture by the dried coal, and that it can be abandoned provided that the moisture dishes bear well‐fitting covers, and that the time between drying and weighing is reduced to a minimum.