bluuebunny/crossref_metadata_2025 huggingface dataset:
Fischer‐Tropsch waxes VII. The thermal conductivity of hard wax
Authors: Le Roux Johannes H. , Smith Roy D. F. , Turner Richard , Weidema Onno
Published: July 2010

The method used to measure conductivity consisted of embedding resistance wire, around which thermocouple wire had been wound, in the wax. An electric current was passed through the wire and temperature rise was recorded as a function of time. The determination was repeated at various temperatures from 20 to 120 °C, i.e. in the solid and liquid states.

The resulting conductivity‐temperature curve has an S shape, like the curves for specific volume and most other physical properties of substances that are crystalline in the solid state. Equations for reduced thermal conductivity were applied. For the solid state external degrees of freedom could be calculated and the partially crystalline nature was confirmed. Experimental and predicted values for reduced conductivity of molten wax differed somewhat, probably because of persisting order in the liquid state. There is a retrograde tendency in conductivity above the melting point. According to the literature measurements on alkanes are likely to be subject to errors due to convection unless extreme precautions are taken. This effect could cause the retrogression.
Simultaneous production of α‐amylase, β‐glucanase and proteolytic enzymes by Bacillus subtilis
Authors: Markkanen Pertti H. , Bailey Michael J.
Published: July 2010

The simultaneous production of α‐amylase, β‐glucanase and proteolytic enzymes by Bacillus subtilis has been studied. The effect of culturing conditions on the simultaneous production of these enzymes has also been investigated. Two known strains were used as standards, the other strains having been isolated and selected in this laboratory for their high enzyme production properties. Of the newly isolated strains three had better enzyme production properties than the standard strains. Selective inhibition was employed to separate total proteolytic activity into two fractions. The strain K160, which was the best strain for enzyme production, produced very few heat stable (100 °C) spores in the culturing conditions used. Enzyme production was correlated with sporulation, which reached its maximum value after about 30 h cultivation. α‐Amylase reached its maximum activity at the same time as sporulation, as did alkaline protease. The maximum for neutral protease activity, however, occurred at an earlier stage, whilst β‐glucanase activity usually continued to increase till the end of the cultivation (48 h). The optimum temperature, agitation and aeration values were determined for the production of enzymes in fermentor cultivation. β‐Glucanase showed remarkably little susceptibility to altered culturing conditions, as did alkaline protease. Sporulation level was always low (5 to 10%) in those cultivations in which enzyme activities reached their maximum values.
Production of phenylacetic acid by the liquid phase oxidation of acetophenone with sulphur in the presence of aqueous ammonia
Authors: Jain Jitendra K. , Chandalia Sampatraj B.
Published: July 2010

The liquid phase oxidation of acetophenone by aqueous ammonia and sulphur to phenylacetamide and/or phenylacetic acid was investigated in a stainless steel autoclave maintained under autogenous pressure. The effects of type and amount of solvent, amount of sulphur, concentration of acetophenone and ammonia, temperature and period of reaction, and the presence of impurities in commercial grade acetophenone, on the conversion and yield of phenylacetamide and/or phenylacetic acid were studied with a view to obtain the most suitable conditions for the production of phenylacetic acid. Since the product was a mixture of phenylacetamide and phenylacetic acid, hydrolysis of phenylacetamide was studied with a view to obtaining phenylacetic acid. Also, the solubility of phenylacetamide in water was determined.
Characterisation of manganese dioxides II. Kinetics of Interaction with Manganese (II) Ions in Aqueous Solution
Authors: Rophael Magdy W. , Malati Mounir A. , Barnes Keith F. , Pulford Richard J.
Published: July 2010

The interaction between MnO2 (I.C.S. No. 5), in the Na+ form and 54Mn2+‐labelled solution at pH 6 involves: a rapid process assumed to be Na+/Mn2+ ion‐exchange and a slower process assumed to involve the exchange between Mn2+ ions in solution and Mn ions in a surface phase. The activation parameters ΔH# and ΔS# were found to be 52 and 83 kJ mol−1 and −130 and −63 J mol−1 for the two processes respectively. Exposing the solid to a flux of moderated neutrons had no effect on the rate of the second process. The exchange of Mn ions from the solid to the solution was demonstrated using 56Mn‐labelled solid and inactive Mn2+ solution. There was evidence of a still slower process.
The microstructural and hardening behaviour of tricalcium silicate pastes in the presence of calcium chloride
Authors: Traetteberg Aud , Ramachandran V. S.
Published: July 2010

A sequential examination of strength development in terms of microhardness was studied during paste hydration of C3S in the presence of 2 and 5% CaCl2 and at w/s ratios of 0.3 or 0.5. An attempt has been made to relate strength with microstructural features studied by means of Scanning Electron Microscopy. Generally, at earlier periods it was found that the 2% addition of CaCl2 gave the strongest material; the effect was most pronounced in the 6‐month sample of the series with 0.3 w/s. The high strength for the sample prepared at a w/s ratio of 0.3 may be related to a high CaO/SiO2 C‐S‐H‐phase, low porosity, and possibly a hydrated calcium hydroxy chloride complex. The pore size distribution was also measured. In general, the higher the porosity the lower the strengths but the relationship was not perfectly linear even on the semi‐logarithmic plot.
Crystallisation of pentaerythritol
Authors: Rogers John F. , Creasy Dennis E.
Published: July 2010

Growth measurements were made of pentaerythritol crystals in both fluidised beds and stirred suspensions. The measurements were made in both the presence and absence of the two by‐product impurities known to be normally present in the commercial material. Maximum growth rates of the order of 10−9m/s were observed with activation energies of between 100 and 200 kJ/mol depending on the sample tested. The growth rate was second‐order with respect to super‐saturation. The two main impurities were found not to greatly influence the growth rate. There was evidence that a so far undetected third impurity, which was present in only trace amounts, was responsible for the very low growth rates observed.
Preparation and application of some new sulphur dyes
Authors: Osman A. M. , Metwally S. A. M.
Published: July 2010

A new series of sulphur dyes was prepared by fusion of aminoquinones and aryl‐azo compounds with sodium polysulphide. These dyes possessed all round good fastness properties and their tendering effects on cellulosic materials were estimated. The complex chemical nature of the prepared dyes was investigated and representative structural formulae were suggested.
The reactivity of calcium oxide towards carbon dioxide and its use for energy storage
Authors: Barker Ronald
Published: July 2010

By using calcium carbonate powder of particle size ∼ 10 nm (and therefore of high surface area) it has been shown that the reaction CaCO3 ⇄ CaO + CO2 can be made almost wholly reversible. A reactivity of 93% was achieved, (i.e. 93% of the calcium oxide reacted with carbon dioxide) and this was maintained for 30 24‐h decomposition‐back reaction cycles at 629 °C with no detectable decrease. This material has an energy storage capacity of 200 Wh/lb, but only about 1 kWh/ft.3 When this calcium carbonate was pressed, however, to increase its bulk density (from 0.1 to ∼ 1 g/ml) there was a large decrease in its surface area and a smaller decrease in its reactivity on undergoing a few decomposition and back reaction cycles. Scaling up of the sample size from 20 mg to 10 g only had a small (× 3) effect on the rates of decomposition and back reaction.
Correlation of salt effect on vapour‐liquid equilibria for benzene‐ethanol system
Authors: Sada Eizo , Kito Shigeharu , Yamaji Hiroshi , Kimura Masato
Published: July 2010

A correlation of salt effect on vapour‐liquid equilibria for nonaqueous binary system is presented. The correlation is applicable to systems in which the salt is dissolved in only one of the volatile components. Assumptions are made to obtain a correlation on the basis of a simplified mechanism of salt effect. The main feature of this correlation is that it does not require an experimental parameter for the salt effect. The applicability of this method is examined by using new experimental salt effect data on benzene‐ethanol azeotropic mixture for the addition of lithium chloride, calcium chloride and zinc chloride. It was found from the examinations that the prediction of the vapour phase composition was successful.
Studies on the system sodium oxide‐calcium oxide‐silica‐water
Authors: Blakeman Elizabeth A. , Gard J. Alan , Ramsay Cameron G. , Taylor Harry F. W.
Published: July 2010

In hydrothermal reactions of lime and quartz with water or aqueous NaOH at 150 °C or 180 °C and Ca: Si = 0.83, the rate of reaction of the quartz increases with NaOH concentration. At 180 °C and Ca: Si = 0.83, the conversion into tobermorite of the semi‐crystalline calcium hydrosilicate initially formed occurs more slowly at NaOH concentrations of 0.15–2.00 M (NaOH: SiO2 = 0.05 to 0.63) than in water or 5 M‐NaOH. With long reaction times at 180 °C and Ca: Si = 0.83, increasing NaOH concentration causes pectolite to replace xonotlite as the main product. At very low water contents, NaCaHSiO4 is formed; this compound is conveniently made by grinding together solid NaOH, Ca(OH)2 and quartz in normally humid air and heating the mixture in a closed vessel at 180 °C.
Thermal alkylation of aromatic nucleus with aryl benzyl ethers
Authors: Osman A. M. , Badr M. Z. A. , Aly M. M. , El‐Sherief H. A. H.
Published: July 2010

The introduction of the benzyl group into the aromatic nucleus is brought about by heating benzyl‐α‐ and β‐naphthyl ethers with the aromatic compounds, such as, naphthalene, 2‐methylnaphthalene and isoquinoline. It has been concluded that the reaction depends initially on homolytic fission of the alkyl aryl ether into aryloxy and alkyl free radicals which are able to react with the aromatic nucleus. The homolytic mechanism of the alkylation studied and the isomer distribution in the alkylation products separated are discussed on bases of theories of free valency and atom localisation energy of aromatic compounds.
On the mechanism of the acid‐catalysed arylation of anthraquinones
Authors: Clark M. C. , Marley T. J. , Lowe P. A.
Published: July 2010

Schmidt discovered in 1925 that an unusual arylation occurred when 1,5‐diamino‐4,8‐dihydroxyanthraquinone‐3,7‐disulphonic acid dissolved in conc, sulphuric acid containing boric acid was treated with phenols or anisole. Schmidt incorrectly assumed that the p‐hydroxyphenyl or anisyl group replaced a sulphonic acid group. It has now been shown that this reaction is a stereospecific Friedel‐Crafts type arylation, the aryl moiety entering ortho to the amino group and trans to the sulphonic acid group. The corresponding 3‐monosulphonic acid undergoes the same reaction.
The effect of heat on metal incorporated silica gels
Authors: Girgis B. S. , Mourad W. E.
Published: July 2010

Silica gel prepared under varying conditions indicated that, in addition to the pH and kind of acid, the mode of adding the solutions govern the evolution of surface area of the produced xerogel. Co‐precipitation with the oxides of iron, copper, or nickel showed a marked effect in decreasing the surface area of the dry gel. Xerogels incorporated with iron oxide suffered from a sharp sintering that appeared upon heating to 900 °C. Copper oxide‐incorporated silicas showed a small decrease in surface area at the same temperature. However, silica incorporated with nickel oxide seems to be resistant to heat treatment at 900 °C, and exhibits only a small change in surface area. Acid treatment of the incorporated silicas resulted in negligible variations in surface area, probably due to the low content of oxides.
The use of ferricyanide for the production of 3‐keto sugars by non‐growing suspensions of Agrobacterium tumefaciens
Authors: Fensom Anthony H. , Kurowski W. Martin , Pirt S. John
Published: July 2010

Ferricyanide serves as an electron acceptor for the conversion of sucrose and other sugars to 3‐keto derivatives by non‐growing suspensions of Agrobacterium tumefaciens. The rate of conversion of sucrose to 3‐ketosucrose is 4‐ to 5‐fold greater in the presence of ferricyanide than the aerobic rate. A continuous flow apparatus in which the cells are retained by a membrane filter while fresh sucrose and ferricyanide are passed through the suspension is described and has been used for study of the kinetics of ferricyanide reduction and 3‐ketosucrose production. The use of ferricyanide obviates the need for aeration for effecting this sugar transformation and has additional advantages in view of the increased rate of reaction. It is proposed that the principle may be extended to other microbial oxidations. The continuous flow apparatus may also have general applicability to study of the kinetics of product formation by non‐growing cell suspensions.
High‐slag cement mortars for brickwork and renderings
Authors: Kamel Abdel Aziz H. , Hassanein Ahmed , Abdel‐Azim Nazek
Published: July 2010

The suitability of clinker‐activated high‐slag cement mortars for use in brickwork construction and in rendered finishes, has been investigated. The study was carried out on a slag cement composed of 80% granulated slag, 15% clinker and 5% raw gypsum; its specific surface area was 4000 cm2/g. It was found that the slag cement mortars and cement‐lime mortars of the proportions commonly used in practice, have higher water‐retentivity than the corresponding mortars of ordinary Portland cement, and that their strengths are comparable to those of the latter mortars.
Carboxylation of o‐dichlorobenzene under pressure
Authors: Goswami A. K. , Palit S. K.
Published: July 2010

When o‐dichlorobenzene was carboxylated with carbon monoxide in presence of water at high pressure the conversions to phthalic acid and benzoic acid at the optimum reaction conditions were 6.20% and 35.80% respectively without any catalyst, while with a catalyst (nickel iodide on silica gel; Ni : SiO2 = 50 : 50) these conversions were 8.90% and 39.85% respectively. Use of catalyst reduced the optimum temperature and pressure for the conversion to phthalic acid, while it reduced the optimum pressure and residence period for the conversion to benzoic acid.
Antifouling paints II. A more detailed examination of the effect of pigment volume concentration
Authors: Marson Frank
Published: July 2010

The effect of pigment volume concentration upon the leaching of soluble pigments from insoluble binders has been studied and the results used to extend a previously described1 theoretical treatment. The number of interconnecting holes between the cavities left after solution of the pigment from the insoluble binder is assumed to be related to the pigment volume concentration in a similar way to the number of contacts made by smooth spheres regularly packed at the same solids content. An empirical equation is used to relate the number of contacts made between spheres to their density of packing, and consequently to relate the number of interconnecting holes between cavities to the pigment volume concentration.

Predictions based on the resulting relationship are compared with the leaching characteristics measured for three different coating compositions, each made with a range of pigment volume concentrations using two different vinyl resins and two grades of copper (I) oxide pigment. The predicted variations with pigment volume concentration of initial leaching rate, and of initial rates of decrease in leaching rates, hold reasonably well for pigment volume fractions between 0.30 and 0.80, the full range studied. Longer term leaching behaviour appears predictable only for paints of pigment fractions above about 0.45; anomalies below this figure are attributed to lack of pigment solution.

Statistical analysis of experimental leaching rate data indicate that the initial leaching rates are unaffected within limits by the type of binder and pigment. The two copper oxide pigments used behaved similarly. However, the kind of binder used does affect the rate of decrease in leaching rate. The experimental data is consistent with the theoretical model employed and with the concept that the thickness of binder separating pigment particles and hence the interconnecting hole size remains approximately constant irrespective of pigment volume concentration.
Interaction of gas bubbles with liquid lead
Authors: Ali Anwar , Ray Hem Shanker
Published: July 2010

The interaction of bubbles of hydrogen and argon‐oxygen mixtures with liquid lead has been investigated using an oxide solid electrolyte cell of the type magnified image where O denotes oxygen, of variable concentrations dissolved in molten lead.

Oxygen concentration in molten lead has been varied through bubbling oxidising or reducing gases. The variation in concentration has been obtained by measuring continuously the cell e.m.f. by a recorder. The effects of bubble size and temperature on mass transfer coefficient of oxygen during oxygen dissolution and oxygen removal operations have been studied.

The liquid phase mass transfer coefficient increases with decreasing bubble size and increasing temperature. The observed variations agree well with equations available in the literature for low temperature liquids.
Thermal decomposition of zinc oxalate dihydrate: Kinetics of dehydration and pyrolysis in various atmospheres
Authors: Mikhail R. Sh. , Guindy N. M. , Ali I. T.
Published: July 2010

Thermogravimetric analysis has indicated that a convenient range for the study of Zn(COO)2.2H2O dehydration is 120–300 °C, while for pyrolysis it is 320–400 °C. Kinetics of isothermal dehydration and pyrolysis were studied as two consecutive steps in various atmospheres, namely in constant water vapour pressure of 4.8 and 8 mm Hg, in air saturated with water vapour at 25 °C and in vacuo. The kinetic data indicated that dehydration is a pseudo‐first order reaction, which is highly dependent on the surrounding atmosphere. The mechanism of dehydration is either activated diffusion (alternatively surface diffusion) for dehydration in vacuo or in low water vapour pressures, or activated desorption for dehydration in presence of high water vapour pressure. On the other hand pyrolysis is independent of the prevailing atmosphere, and the energy of activation is of the order of the enthalpy change of the reaction.

Earlier studies have involved contact of the dehydrated oxalate with air, or have obscured the influence of the prevailing atmosphere, by dehydrating the sample material at the pyrolysis temperature. These conditions are considered in the present investigation.
Synthesis of isohydrazones by the reaction of chlorine and ammonia in the presence of a ketone (a new hydrazine process) II. A colorimetric method of analysis of organic intermediates used in the synthesis of hydrazine
Authors: Jermyn T. J. , Jeffreys G. V.
Published: July 2010

A colorimetric method of analysis of azines and isohydrazones which is based on their reaction withp‐dimethylaminobenzaldehyde is discussed. A second method of analysis involving their conversion to hydrazine sulphate has also been developed and excellent agreement between the two methods has been obtained. The colorimetric technique is extremely sensitive, and it was found that at low concentrations the effects of water and ammonia on the calibrations was negligible.
Synthesis of terpene alcohols from isoprene oligomers
Authors: Watanabe Shoji , Suga Kyoichi , Fujita Tsutomu , Takasaka Nobuo
Published: July 2010

Various terpene alcohols were prepared from isoprene oligomers via two steps: epoxidation with peracetic acid and isomerisation with aluminium triisopropoxide. For example, 2‐methylene‐6‐methyl‐7‐octene‐1‐o1 was prepared from 2,6‐dimethyl‐1,7‐octadiene. From 2,6‐dimethyl‐2,7‐octadiene, 3,3,6‐trimethyl‐1,5‐heptadiene, 2,7‐dimethyl‐2,6‐octadiene, 2,6‐dimethyl‐1,3,6‐octatriene, 1‐methyl‐4‐isopropenyl‐1‐cyclohexene, and 1,5‐dimethyl‐1,5‐cyclooctadiene, the corresponding alcohols were obtained, respectively.
Exocellular β‐1,3 glucanase synthesis by continuous‐flow cultures of a thermophilic streptomycete
Authors: Lilley G. , Rowley B. I. , Bull A. T.
Published: July 2010

Production of a β‐1,3‐glucanase by a thermophilic streptomyces species in chemostat cultures was studied. In growth medium containing glycerol, synthesis of β‐1,3‐glucanase synthesis occurred at dilution rates less than 0.20 h−1. Chemostat cultures operating under non‐steady state conditions were optimal for glucanase production. Under the latter conditions of growth the extent of enzyme synthesis was dependent on the magnitude of the step down in dilution rate from an existing steady state value. Furthermore, induction of β‐1,3‐glucanase by gentiobiose only occurred during non‐steady state growth.
The use of continuous ion exchange (CIX) in copper recovery problems
Authors: Naden D. , Evans J. P.
Published: July 2010

Solid ion exchange using commercially available resins is suggested as a method for recovering copper directly from the slimes streams in copper recovery operations. The presence of slimes often reduces the efficiency of vat leach operations and the slimes are therefore separated and treated in a separate sulphuric acid leach stream. A similar pre‐leach separation of sands and slimes is suggested in flowsheets where a fine ore grind results in the necessity to wash the leached ore in large counter‐current washing and thickening units with a resulting dilution of the leach stream. Separation of the slimes, with CIX recovery of copper directly from the slimes stream, greatly reduces the size of the leached ore washing units and results in lower flows of more concentrated solution. Copper specific resins are not required in these flowsheets as the high sulphuric acid CIX eluate is passed to the sands leach unit as make up acid and all the copper may then be recovered by a copper specific solvent extraction step in the sands leach stream. Conventional equipment may be used for all the unit operations suggested.

A laboratory investigation has shown that commercially available resins with suitable properties are available. Techniques of estimating a CIX process design from laboratory scale tests, for any process situation, have been developed by Davy Powergas Research and Development Division for the resins examined.
The production of NPK fertilisers by ion exchange
Authors: Knudsen K. C.
Published: July 2010

Ion‐exchange technique is used for the production of chloride‐free NPK‐fertilisers. Phosphate Rock (calcium phosphate) is solubilised in nitric acid, and calcium ions in the solution are exchanged with potassium ions from a cation exchanger, which is regenerated with a potassium chloride solution. The process permits low cost production of high grade fertilisers because it is based on the cheapest available raw materials. Special ion exchange method and apparatus have been developed in order to avoid excessive dilution of the product solution, to obtain low chemicals consumption for regeneration and to cope with the demand for a simple and reliable system.
Bound water in sewage sludges and its relationship to sludge surfaces and sludge viscosities
Authors: Forster C. F.
Published: July 2010

An examination of activated and digested sludges has shown that surface components are significant in determining the rheological characteristics of these sludges. On the basis of a series of enzymic treatments, it would appear that in activated sludge the most important constituents are polysaccharide and protein; whilst in digested sludge, lipopolysaccharide and, at times, proteins are the most significant surface polymers. Subsidiary studies showed that the bound water content of the sludges was associated with the rheology and that this association could be modified by the action of metal ions.
Effect of the polymer matrices on the immobilisation of microbial cells by radiation polymerisation
Authors: Kumakura Minoru , Kaetsu Isao
Published: July 2010

Streptomyces phaeochromogenes cells were immobilised by radiation polymerisation, at low temperature, using various acrylate and diacrylate monomers. The form and enzymatic activity of the immobilised cell composites were affected by the molecular structure of the monomers. The activities of the composites from acylate and diacrylate monomers increased with increased numbers of methylene or ethylene glycol units in the monomers. The water content of the immobilised cell composites was also affected by the molecular structure of the monomers. The pH and heat stabilities of the immobilised cell composites were increased when the polymer matrix had a porous sponge structure.
Cellulolytic properties of Chaetomium crispatum
Authors: Geeraerts Herman A. M. , Vandamme Erick J.
Published: July 2010

The cellulolytic properties of a Chaetomium crispatum strain were investigated. The cellulolytic enzyme complex i.e.: exo‐1,4‐β‐glucosidase (EC 3.2.1.74); endo‐1,4‐β‐glucanase (EC 3.2.1.4.) and β‐glucosidase or cellobiase (EC 3.2.1.21) displayed optimal activity at pH 5.0 and 25°C. Although carboxymethyl‐celluloses are the usual pseudo‐substrates for this enzyme complex, those with a high degree of substitution gave rise to poor growth and low cellulase activity. Insoluble crude cellulosics such as newsprint, recycled paper, rice and flax straw were substantially solubilised at 28°C within 3–5 days of fermentation. A study of the cellulase‐complex formation during the growth cycle revealed that β‐glucosidase was produced mainly intracellularly in the early exponential phase, while the overall exo‐1,4‐β‐glucosidase and endo‐1,4‐β‐glucanase formation gradually increased during the total fermentation cycle. The mycelial protein of Chaetomium crispatum grown on crude cellulosics displayed a favourable amino acid pattern, indicating its potential value as a source of single cell protein (SCP).
The significance of ATP in the settlement of activated sludge
Authors: Clarke Alan R. , Forster Christopher F.
Published: July 2010

A laboratory‐scale activated sludge plant treating simulated coke oven liquors was used to examine the settleability of the sludge in relation to its ATP concentration. On the basis of the data obtained a model was developed which described sludge settlement and was based on Monod kinetics and sludge activity (measured as ATP). The model was tested against data obtained previously from a sewage‐fed plant.
An extended bottleneck model: Accounting for the metabolic turnover effect in microorganisms
Authors: Agrawal Pramod , Lim H. C. , Ramkrishna D.
Published: July 2010

The bottleneck model proposed by Powell1 can describe the growth rate hysteresis effect, but fails to account for the stationary state of microbial cultures. It is modified to obtain an extended bottleneck model (EBM), which adequately represents the stationary state of microbial cultures. The basis for modification is the metabolic turnover of proteins in microorganisms. Under special conditions the EBM can be reduced to the Powell bottleneck model or the Monod model. The EBM yields improved predictions of the transient growth of E. coli in nitrogen limited cultures.
Mechanisms of biofilm formation on aluminium tubes
Authors: Bott T. R. , Miller P. C.
Published: July 2010

The development of biofilms in contact with flowing liquids was monitored in a biofouling culture apparatus which contained aluminium tubes and which was inoculated with Pseudomonas fluorescens. Tests were carried out in which, alternately, the nutrient feed or the bacterial supply was stopped. Results showed that once the surface is colonised, the predominant mechanism for biofilm development was growth within the film. Maximum biofilm development occurred at liquid flow velocities around 1 m s−1. Rapid development occurred even in the presence of very small amounts of nutrient.
A study of biogas generation from coconut pith
Authors: Radhika L. G. , Seshadri S. K. , Mohandas P. N.
Published: July 2010

Biogas production from cowdung is well studied. Coconut pith is an agricultural waste available in large quantities in Kerala: the possibility of using coconut pith for biogas production was studied. It was found that coconut pith in combination with cowdung gives considerable amount of biogas, while alone it did not produce any gas. The optimum combination was found to be 60% pith and 40% cowdung. Study of dilution effect on the slurry showed that the optimum solid‐liquid ratio is 1:20. Partial removal of lignin from pith increased the rate of biogas production. Gas produced from a mixture of cowdung and pith was found to have a higher methane content than that produced from cowdung only.
The influence of COD, hydraulic, temperature and pH shocks on the stability of an unheated fluidised bed reactor
Authors: Bull Michael A. , Sterritt Robert M. , Lester John N.
Published: July 2010

An anaerobic fluidised bed reactor, operating at room temperature, was used to treat a synthetic meat extract wastewater with an influent COD of 1250 mg 1–1. It was subjected to large increases in influent COD and flow rate for 4‐and 8‐h periods. The reactor tolerated these transient changes satisfactorily and with no long term detrimental effects. Normal operation was regained within 9h. Variations in operating temperature and influent pH were also examined. Four hour duration, 10°C temperature increases and decreases had little effect on effluent quality, but long term operation at a low influent pH was considered inadvisable. A simulated working week experiment was carried out with a 48‐h 90% influent flowrate reduction, followed by a return to normal operation. The reactor tolerated these conditions well, with full recovery made within a few hours. The resistance of the reactor to unfavourable process conditions is discussed. The extrapolation of laboratory data to practical operating conditions is also considered.
Optimisation of cellulose conversion into fungal cell mass
Authors: Hecht Volker , Schügerl Karl , Scheiding Wolfgang
Published: July 2010

Chaetomium cellulolyticum was cultivated on Avicel and/or stream‐and NH3‐pre‐treated straw in a 20 litre stirred tank reactor with batch and/or fed‐batch operation. The influence of the substrate concentration, the impeller speed and the fed‐batch operation on cell productivity was investigated. Steam‐pretreated straw can be better utilised by the fungus than NH3‐pretreated straw. The optimal conditions at which maximum cell productivity and/or maximum cell mass concentration can be attained were evaluated for stream‐pretreated straw. At the beginning of the growth phase the oxygen consumption rate reaches a significant maximum. At this point the enzyme activity begins to increase. The investigations with Avicel indicate that the cell productivity could be significantly increased by fed‐batch operation. A microprocessor‐controlled fed batch process controlled by alkaline consumption is recommended.
Electron‐transfer coupling in microbial fuel cells: 1. comparison of redox‐mediator reduction rates and respiratory rates of bacteria
Authors: Roller Sibel D. , Bennetto H. Peter , Delaney Gerard M. , Mason Jeremy R. , Stirling John L. , Thurston Christopher F.
Published: July 2010

Redox mediators promote electron transfer in microbial fuel cells. The reduction of a range of redox mediators by bacteria was studied in some detail in order to identify effective mediator—organism combinations. Rates of reduction of mediator dyes by bacteria were measured spectrophotometrically at 30°C under anaerobic conditions for standardised concentrations of organism, substrate and dye. The kinetics of dye reduction showed two general patterns: a simple, exponential curve or a complex curve with an initial linear rate followed by a faster exponential rate of reduction. Dye‐reduction rates were greater than rates of oxygen consumption (QO2) for several combinations of organism and redox dye. Thionine, brilliant cresyl blue, methylene blue and benzyl viologen were tested in combination withAlcaligenes eutrophus, Azotobacter chroococcum, Bacillus subtilis, Escherichia coli, Proteus vulgaris, Pseudomonas aeruginosaandPseudomonas putida, using glucose and succinate as substrates. Rates of reduction of alizarin brilliant blue, 2,6‐dichlorophenolindophenol, gallocyanine, new methylene blue,N,N‐dimethyl‐disulphonated thionine, phenazine ethosulphate, resorufin, safranine‐O, phenothiazinone and toluidine blue‐O were also measured withPr. vulgarisonly. ForE. coli, both QO2and the rate of thionine reduction increased with increasing temperature in the range 25 to 37°C, but forPr. vulgaristhionine reduction rates did not correlate with temperature in this way. Dye‐reduction rates and QO2forAz. chroococcumwere dependent on the components of the washing solution and/or the temperature at which cell suspensions were prepared. The results are discussed in relation to the use of these dyes as electron‐transfer mediators in microbial fuel cells.
CO2 absorption rate in an algal culture: Effect of pH
Authors: Lee Yuan‐Kun , Pirt S. John
Published: July 2010

In a CO2‐limited algal culture, grown in a tubular loop photobioreactor, the maximum rate of CO2 absorption increased about 1.5‐fold when the culture pH value was increased from 6.5 to 7.5 with a fixed initial PCO2. The mean volumetric CO2 transfer coefficient (KLa) increased about 1.8‐fold. The bicarbonate ion concentration would be increased 10‐fold by the pH increase. The effect of pH on the absorption rate is attributed to changes in either the CO2 diffusivity, the gas bubble size, or the CO2 reaction kinetics at the gas/liquid boundary.
Production and properties of Aspergillus niger inulinase
Authors: Derycke Dirk G. , Vandamme Erick J.
Published: July 2010

An inulinase producing Aspergillus niger strain was isolated from Compositae rhizosphere soil samples. High inulinase levels were produced on a corn steep liquor (CSL)‐maltose medium in the absence of inulin at 28°C within 110 h of fermentation. Media based on CSL‐sucrose yielded high cell‐bound inulinase activity; on inulin‐based media the enzyme was mainly extracellularly produced. Both crude extra‐and intracellular inulinase preparations displayed identical pH and temperature optima with maximal activity at pH 4.3–4.4 and at 55–56°C. These properties are favourable in view of large scale inulinase application for pure fructose production. High operation temperatures would avoid microbial contamination of reactors and would allow the use of high inulin‐substrate concentrations, a limiting factor in obtaining high conversion ratios. The remarkably low pH optimum prevents colour formation and undesirable chemical side reactions. An advantageous low ratio of invertase to inulinase activity (S/I value) of 0.85 was found for the crude extracellular enzyme preparation. Crude inulin (chicory) extracts are hydrolysed faster than pure inulin. Apart from inulin (100% hydrolysis), sucrose (45%) and raffinose (20%) are also hydrolysed, and no liberation of oligomers or of sucrose from inulin was observed. These facts indicate that the A. niger enzyme is an exo‐acting inulinase. The above characteristics make this A. niger inulinase an industrially attractive enzyme for the preparation of pure fructose from inulin‐containing agricultural crops.
Preparation of rigid, low‐density, flame‐retardant polyurethane foams from whey permeate
Authors: Viswanathan Tito , Burrington D. , Richardson T.
Published: July 2010

The disposal of whey and whey permeate derived from the cheese industry is a serious economic and environmental problem. Lactose in whey permeate was used to synthesise polyether polyols from which rigid, low‐density polyurethane foams were prepared. Resultant foams were comparable to those made from commercially available sucrose‐based polyether polyols. Brown‐coloured lactose polyether polyols are characterised by low viscosity and high carbonyl content. Urea incorporated into these polyether polyols yields flame retardant (self‐extinguishing) foams. Urea also reduced the amount of phosphorus and/or halogen based fire retardants needed to make the foams non‐burning. A preliminary economic analysis indicates that whey‐based polyether polyols can be prepared at a cost savings of up to 36% compared to the sucrose counterparts.
Effect of external mass transfer in a packed bed reactor system for a reversible enzyme reaction
Authors: Park Young H. , Han Moon H. , Rhee Hyun‐Ku
Published: July 2010

A mathematical model was developed to describe the effect of external mass transfer for a packed‐bed enzyme reactor in which a reversible, one‐substrate, two‐intermediate enzyme reaction took place. The model equation was applied to the analysis of an immobilized glucose isomerase reactor system. A Colburn‐type mass transfer correlation was obtained from the Colburn j‐factor versus Reynolds number plot: i.e., jD = 0.045NRe−0.48. The values of mass transfer coefficient for the system under study ranged from 0.01 to 0.1 cm h−1 depending on the substrate flow rate. Very good agreements were observed between the computer simulation using a plug flow reactor model with the derived mass transfer correlation and the experimental results obtained from the packed‐bed reactor operation.
Fermentation inhibitors in wood hydrolysates derived from the softwood Pinus radiata
Authors: Clark Thomas A. , Mackie Keith L.
Published: July 2010

Sugar solutions obtained by dilute acid hydrolysis of the softwood Pinus radiata contain various wood‐derived components which are inhibitory to the ethanolic fermentation by the yeast Saccharomyces cerevisiae. A detailed examination of these compounds indicated that a range of low molecular weight phenolics, related in structure to ‘Hibberts ketones’, may be identified as the most inhibitory materials. These lignin‐based compounds, although present at low levels compared with the carbohydrate‐degradation compounds, are approximately 10 times more inhibitory.
Studies on the contamination of feed molasses for continuous ethanol production in an immobilised yeast cell reactor
Authors: Varma R. , Baliga B. A. , Chatterjee S. K. , Ghosh B. K. , Dalai P. M. , Srivastava A. K. , Karanth N. G.
Published: July 2010

With the present world problem of fossil fuel limitations, alcohol production from renewable resources such as sugar cane molasses, particularly by continuous processes, has become important. In continuous processing, feed contamination problems could become critical. A useful inexpensive technique, which can minimise these problems when molasses is used as the substrate, is to ensure that the time period elapsing after dilution of molasses and before feeding to the reactor is minimal. Experiments were conducted to determine how long the clarified molasses feed solution could be kept under non‐sterile conditions without affecting the performance of an immobilised whole cell reactor for alcohol production. For this purpose, the fastest growing contaminant (under the prevailing conditions) present in molasses feed solution was isolated by plating technique. From the initial total number of contaminant microorganisms in the feed solution, and from the experimentally determined generation time of the fastest growing contaminant cells, the safe period of storage of diluted molasses was calculated. This value was in reasonable agreement with the experimental observations.
Measurement of oxygen transfer coefficient under growth conditions by dynamic model moment analysis
Authors: Mignone Carlos F. , Ertola Rodolfo J.
Published: July 2010

A rapid and reliable method of Kla estimation under growth condition, based on the first moment analysis, is proposed. The method consists of a sudden change of agitation speed while the aeration rate is held constant: the first moment method of response curve analysis is used for estimating Kla. With the proposed method, it is not necessary to consider the gas kinetics because the composition of the gas phase remains constant.
Immobilised biocatalysts—a critical review
Authors: Rosevear Alan
Published: July 2010

This review examines the strengths and weaknesses of immobilisation when used as a technique for deploying enzymes and cells in systems .Suitable methods for preparing immobilised conjugatcs are described ; the potcntial benefits of immobilisation for industrial products. analysis and academic studies are discussed..
Food proteins: Sources and properties
Authors: West Stuart I.
Published: July 2010

The three major functional proteins are casein, egg white and soya, and these have been used by the food industry of over 20 years. Many novel proteins have been suggested as alternatives, but only the proteins produced from cheese whey have gained widespread use. The others have failed to gain wide acceptance because of lack of functionality, off‐flavours and the presence of toxic compounds. It is suggested that there may be a switch away from trying to produce new low‐priced broad‐range functional proteins to high‐priced specialist proteins intended for specific tasks.
Precipitation of food proteins and their recovery by centrifuging and ultrafiltration
Authors: Hoare Michael , Dunnill Peter
Published: July 2010

Food proteins in solution and as precipitates are subjected to intense forces during industrial processing. Given proper equipment design, the individual protein molecules in solution are remarkably robust; this extends the potential range of conditions under which they can be processed. Protein precipitates are sensitive to shear fields, and this influences the design of precipitation reactors and recovery equipment. Ultrafilters represent an alternative to centrifuges for recovery and, with precipitated protein, can yield solids of comparable concentration. The properties of food protein precipitates can be improved, with respect to recovery, by acoustic conditioning. Detailed physical measurements of proteins in solution or when precipitated, and laboratory‐derived kinetic studies of precipitation, can yield information which may be applied directly to industrial operations.
Recovery and utilisation of by‐product proteins of the meat industry
Authors: Ledward David A. , Lawrie Ralston A.
Published: July 2010

The methods available for the recovery and utilisation of proteins from blood and offals are reviewed: special reference is made to the use of controlled enzymic hydrolysis. The texturisation of these proteins into meat‐like analogues, by fibre spinning or thermoplastic extrusion, is discussed.
Microbial processes in mushroom cultivation; a large scale solid substrate fermentation
Authors: Wood David A.
Published: July 2010

The microbial processes occurring during mushroom cultivation are amenable to analysis by a number of experimental approaches. The microbial flora of the composting stage can be examined by microbiological and microscopical methods. The quantity of microbial biomass accumulating in the substrate can be measured by biochemical or microscopical techniques. Biodegradation of the substrate during composting or colonisation by mushroom mycelium can be assessed by chemical methods, assay of degradative enzymes and by following the degradation rate of radiolabelled plant polymers. Analysis of these processes indicates that substrate preparation (composting) is amenable to further control by manipulation of substrate environment and ingredients. Improvement in substrate utilisation might be achieved by strain selection, and further analysis of substrate composition.
The preparative refinement of steroid specific antibodies by affinity chromatography combined with electrophoretic desorption. Apparatus and method
Authors: Müller Robert F. , Palluk Rainer , Kempfle Manfred A.
Published: July 2010

The preparative refinement of antibodies to testosterone and 5α‐dihydrotestosterone was achieved by prepurification (filtration, fractionation with ammoniumsulphate), followed by affinity chromatography of the antiserum. The affinity sorbent was synthesised by coupling 5α‐dihydrotestosterone with Sepharose CL 6B. After elution of the interfering admixture, there was desorption by the use of an electric field, using a specially developed apparatus. This apparatus and the method employed provided preparative amounts of antibodies, without significant impairment of affinity. The interfering self fluorescence of the serum was greatly diminished by this refinement procedure. The refined antibodies obtained were suitable for use with sensitive fluorometric testings (i.e. homogeneous fluoroimmunoassay).
The recovery of uranium and lanthanides during the production of nitrophosphate fertilisers using tertiary amyl alcohol
Authors: Habashi Fathi , Awadalla Farouk T.
Published: July 2010

When phosphate rock is dissolved in nitric acid, phosphoric acid and uranium can be selectively extracted by tertiary amyl alcohol; other impurities including the lanthanides remain in the aqueous phase. Uranium can be recovered from the alcohol phase by selective stripping and the lanthanides from the raffinate by extraction with tributyl phosphate.
The effect of a surfactant on mixer—settler operation
Authors: Horng Jiin‐Shiung , Maa Jer‐Ru
Published: July 2010

A single stage mixer—settler was used to investigate the effect of surfactant on the mass transfer rate in the system water—HNO3—30 vol.% TBP/dodecane. The interfacial tension of this system first falls then rises with increasing sodium lauryl sulphate (SLS) concentration. The addition of SLS makes the stage efficiency, which is closely related to kha, the product of the individual mass transfer coefficient of HNO3 in the aqueous phase, and average interfacial area per unit volume of mixing chamber, to increase significantly due to an increase in the value of a. A maximum kha value of 0.53 litres−1, a minimum value of interfacial tension, and phase inversion which converted the aqueous phase from continuous to dispersed were observed at around the critical micellar concentration (100 parts 10−6) of SLS in the system of an aqueous to organic phase ratio of 0.2.
Adsorption of reaction species for hydrogenation of o‐nitrotoluene on copper chromite under catalytic conditions
Authors: Choudhary Vasant R. , Sansare Subhash D. , Thite Gandhali A.
Published: July 2010

Adsorption of reaction species involved in vapour phase hydrogenation of o‐nitrotoluene (viz. o‐nitrotoluene, o‐toluidine and water) on copper chromite in presence of an inert gas (He) or hydrogen (which is one of the reactants) at temperature (473‐560 K) and partial pressures at which the catalytic reaction is carried out has been investigated using the gas chromatographic pulse technique. The presence of hydrogen was found to cause a very significant decrease in the adsorption of toluidine but a little effect on the adsorption of water. The adsorption data for all the reaction species could be fitted to the Freundlich adsorption equation. The isoteric heats of adsorption obtained from the adsorption isotherm indicated that o‐toluidine and water are physically absorbed, whereas o‐nitrotoluene is chemisorbed on the catalyst. The heat of adsorption of water and o‐nitrotoluene was found to decrease with the increase in the surface coverage, indicating repulsive interactions between the adsorbed species. On the other hand the heat of adsorption of o‐toluidine (in presence or absence of H2) was found to increase with the increase in the surface coverage, suggesting attractive interactions between the absorbed species.