bluuebunny/crossref_metadata_2025_split huggingface dataset:
The stability of lactic acid production in resting suspensions of Lactobacillus delbrueckii
Authors: Rees John F. , Pirt S. John 
Published: July 2010

AbstractThe stability of resting glycolytic activity (RGA) i.e. lactic acid production from glucose, in non‐growing suspensions of Lactobacillus delbrueckii was examined. Non‐growing conditions were imposed by removal of essential nutrients or by the addition of antibiotics. The stability of RGA was reduced in fast‐grown chemostat cells. Mg2+, reducing agents, the rigorous exclusion of oxygen and a constant supply of energy source gave a five‐fold increase in RGA and a 25‐fold increase in stability in cells deprived of a nitrogen source. Glyceraldehyde‐3‐phosphate dehydrogenase (GAPDH) activity severely limited RGA after about 8 h of incubation. No evidence of excessive ATP accumulation or ADP depletion was found. Addition of chloramphenicol, actinomycin D or mitomycin C decreased RGA stability over a 24‐h period. Addition of yeast extract and tryptone to a mixture containing phosphate, Mg2+, thioglycollate and chloramphenicol gave a three‐fold increase in RGA which lasted for about 1 h. Mg2+ is believed to stimulate the glycolytic sequence directly and oxygen probably inhibits GAPDH by interaction with the ‐SH groups of the enzyme. Tryptone and yeast extract probably stimulate pyruvate kinase activity, and this enzyme is also absolutely dependent on fructose‐1, 6‐diphosphate for activity.
Corrosion inhibition by sodium molybdate
Authors: Armour Alan W. , Robitaille Dennis R. 
Published: July 2010

AbstractThe ability of sodium molybdate to inhibit corrosion of mild steel is demonstrated using laboratory and field test data. Initial evidence is also presented indicating that molybdate inhibits the corrosion of copper and aluminium. Environmental aspects including fish toxicity data are discussed as is the likely mechanism of molybdate inhibition.
Hardened alite pastes of various porosities II. Morphology and microstructure
Authors: Abo‐El‐Enein Salah A. , Mikhail Raouf Sh. 
Published: July 2010

AbstractThe hardened alite pastes were prepared by using initial water:alite ratios of 0.20, 0.30, 0.45 and 0.60. The microstructures of the low and high porosity pastes were investigated by scanning electron microscopy. The results obtained indicated that the cementing system is really a composite material having a structure controlled by the total pore system of the hardened paste. In low porosity pastes, the hydration products are semi‐crystalline; whereas in high porosity pastes, the hydration products possess a massive tabular structure.
Thermal and related studies of some zirconia gels
Authors: Gimblett Gareth , Rahman A. Atiqur , Sing Kenneth S. W. 
Published: July 2010

AbstractThe thermal properties of a number of zirconia gels, prepared with various precipitants, have been studied by thermogravimetry, differential thermal analysis and evolved gas analysis. The results obtained show that ligands derived from the various precipitants are incorporated in these gels and strongly influence their high temperature behaviour. The observed properties are interpreted on the basis of a defect structure involving O2‐ vacancies generated through the removal of these ligands at higher temperatures.
Some engineering aspects of high pressure water electrolysers
Authors: Stickland Richard J. R. 
Published: July 2010

AbstractThe high pressure electrolyser was developed specifically for the UK Ministry of Defence for use on Royal Navy nuclear submarines to produce oxygen for life support. Consequently more attention was paid to safety and reliability than to the cost of production. The development of the electrolytic cell, the subsequent development and engineering required to incorporate the cell into a system which enabled the cell to operate satisfactorily and which controlled the process, rendering it safe in the event of any anticipated failure, is described here. Aspects covered include material selection, the interaction between electrolyte flow and gas purities, prevention of gas mixing, features associated with working at high pressures and automation.
Mechanism of retention of hydrocarbons in reservoir rocks. Role of polar compounds and effect of additives
Authors: De Savignac Alain , Dupin Patrice , Matondo Hubert , Bories Serge , Lattes Armand 
Published: July 2010

AbstractEvidence is given for the involvement of hydrophobic interactions in the retention of hydrocarbons in oil fields. A prerequisite is that the surface of the reservoir rock has to be hydrophobic. This was obtained through adsorption of lipophilic polar compounds. The isotherms for the adsorption of dodecylamine hydrochloride and N‐hexadecylpyridine hydrochloride were plotted. The treated quartz could take up large amounts of toluene. The relationships between some features of the isotherms and the retention phenomenon have been analysed. The effect of water‐structuring additives (e.g. LiF, CaCl2, NaF and guanidine hydrochloride) on the recovery of hydrocarbons was investigated by means of static and dynamic methods.
Microbial degradation of synthetic polymers
Authors: Pirt S. John 
Published: July 2010

AbstractSuccessful processes for the microbial degradation of synthetic polymers began to emerge in 1978. Organisms capable of biodegradation of polyurethane polyester, polyethylene, polyethyleneglycol, polystyrene, polyvinylalcohol, polyacrylonitrile, nylon 3 and nylon 6 were identified. There was a maximum molecular weight for attack and in some cases only oligomers were susceptible. The polymers were converted to biomass or smaller molecules or polymers without certain side groups. The degradation processes should be capable of much improvement by accelerated evolution of the microbial agents in continuous cultures. Co‐oxidation of the polymers with another substrate, for example methane, with methane‐oxidising bacteria as agents is suggested as a possible degradative means. The insolubility of polymers is a serious barrier to microbial attack and constitutes a major problem for investigation. Ultimately bio‐degradation should provide a mild means for the recycling of synthetic polymers with the advantage of greater control over the degree of degradation.
The effect of mixing on the paired dimerisations of methyl acrylate and diethyl malonate
Authors: Johnson David K. , Jansson Robert E. W. 
Published: July 2010

AbstractThe paired dimerisations of methyl acrylate and diethyl malonate have been carried out in a pump cell, a capillary gap cell, a parallel plate cell and a trickle tower cell, and the distributions of products related to the environments in the cells. It is clear that good dispersion of malonate anions is essential for high selectivity, but that too high a dispersion rate leads to loss of current efficiency through the parasitic iodine cycle.
Investigation of factors in the optimisation of penicillin production
Authors: Calam Christopher T. , Ismail Basil A.‐K. 
Published: July 2010

AbstractPenicillin production trials were carried out in stirred 5‐dm3 fermenters to collect data and investigate aspects of the process likely to be important in on‐line optimisation. These included the calculation of growth from the production of carbon dioxide, the relation between age and productivity and the effect of dilution and culture replacement. Three types of media were used, a synthetic medium and complex commercial‐type nutrient media based on corn‐steep liquor or peanut meal together with a nutrient feed and pH control. All gave good results although the synthetic medium tended to show only transient production on some occasions. An equation was devised enabling the correct calculation of the growth curve from carbon dioxide output. It was found that the maintenance energy requirements (as indicated by CO2 production) were much higher with synthetic medium than with complex media. Decay curves (of Qpen vs time) were readily calculated using Shu's17 equation. The highest outputs of penicillin were obtained by dilution or replacement systems, but it was essential to start the process early when the penicillin‐producing enzymes were active and stable. It was also necessary to supply glucose at an adequate rate, to hold dissolved oxygen concentration above 25% and avoid too high cell concentrations. It was concluded that theories of penicillin production based on feed‐rate or dilution, or on the effect of age, are essentially complementary, both aspects being important in determining the optimal course of the fermentation.
Conversion of abienol into tetrahydroepimanool by anaerobic processes in woodroom debarking effluent
Authors: McKague A. B. , Lee E. G‐H. 
Published: July 2010

AbstractThe conversion of abienol into tetrahydroepimanool by anaerobic processes in woodroom debarking effluent is demonstrated. This conversion is used as a preparative method for tetrahydroepimanool.
Metal support interactions in the palladium‐catalysed decomposition of furfural to furan
Authors: Singh Harendra , Prasad Murari , Srivastava Rameshwar D. 
Published: July 2010

AbstractThe catalysed decarbonylation of furfural to furan by palladium‐carbon and pallidium‐alumina has been examined. The results reveal a combination of support effects which are possibly related to a direct electronic support function whereby furfural and hydrogen can be adsorbed on support surfaces with subsequent surface migration to metal sites for reaction.
Experimental problems in the application of the marker‐pulse technique
Authors: Overstall John , Jansson Robert E. W. 
Published: July 2010

AbstractIn principle the marker‐pulse technique provides a simple way of characterising the hydrodynamic regime in electrochemical reactors. However, in practice, a number of experimental difficulties are encountered. These arise from the nature and placement of the electrodes, and from undesired electrical coupling of the marker and detector instrumentation. Methods for minimising these problems and improving experimental data are described.
A mechanistic model for penicillin production
Authors: Bajpai R. K. , Reuß M. 
Published: July 2010

AbstractA mechanistic model for the production of penicillin has been investigated. Contois kinetics of growth coupled with a substrate‐inhibition model for product formation has been used to predict data for batch‐fed fermentation on synthetic and corn steep liquor medium. With the incorporation of oxygen limitation on growth and product formation it has been possible to investigate the effects of feeding rate, initial sugar concentration and the volumetric mass transfer coefficient for oxygen (KLa). Various experimentally observed trends for penicillin fermentation have been predicted qualitatively. Different product formation models have been critically reviewed with respect to the production of secondary metabolites.
Synthesis of some new azopyrazole dyes
Authors: Fahmy Sherif Mahmoud , Badran Abdel Hakim , Elnagdi Mohamed Hilmy 
Published: July 2010

AbstractA variety of new azopyrazolo [1,5‐c]‐as‐triazine dyes have been synthesised via diazotisation of 3‐amino‐4‐arylazo‐1‐pyrazolin‐5‐one and coupling with active hydrogen reagents. These dyed nylon 6, nylon 66, acrylic, polyester, silk and wool with colours ranging from scarlet red to dark brown and may find useful applications.
Studies of the trimethylsilyl derivatives of unhydrated cement and hydrated cement pastes by fourier transform infrared spectroscopy
Authors: Sarkar Asok K. , Roy Della M. 
Published: July 2010

AbstractTrimethylsilyl derivatives (T‐derivatives) of unhydrated cement and hydrated cement pastes were studied by Fourier transform infrared spectroscopy. The infrared spectra of all these derivatives are very similar. However, when the spectrum of the T‐derivatives of the unhydrated cement is subtracted from those of the hydrated pastes, a difference in the characteristics of the siloxane bands is observed in the subtracted spectra. The implications of these observed changes to cement hydration process is discussed.
Effect of addition of poly‐N‐vinylpyrrolidone on the surface characteristics of zirconia gel
Authors: El‐Akkad Taghreed M. 
Published: July 2010

AbstractThe surface characteristics of pure and poly‐N‐vinylpyrrolidone‐containing zirconia gel were investigated by nitrogen adsorption at — 196°C. Structural and phase changes were studied by X‐ray diffractometry and differential thermal analysis. The inclusion of poly‐N‐vinlypyrrolidone did not retard the appearance of the X‐ray diffraction patterns of zirconia gel but only led to a decrease in their relative intensities. Surface characteristics were greatly affected by inclusion of the polymer in the gel, as evidenced by a remarkable increase in surface area, total pore volume and pore radii. The optimum increase was observed for the sample containing 5% of poly‐N‐vinylpyrrolidone. On thermal treatment at 300°C the pure sample exhibited an increase in the micropore volume which can be attributed to perforation of the gel during the evolution of a considerable amount of hydrated water. On the other hand, the inclusion of poly‐N‐vinylpyrrolidone led to a strengthening of the skeletal wall of the gel to withstand perforation. However, thermal treatment at 550°C led to a marked decrease in the surface area, especially for samples containing high percentage of poly‐N‐vinylpyrrolidone, e.g. 10%. This decrease may be attributed to shrinkage of the polymer at higher tempature which led to the disappearance of a great fraction of the area.
Effect of hydrogen sulphide on the deactivation of alumina‐supported ruthenium methanation catalysts
Authors: El‐Sawi Mahmoud , Forzatti Pio , Pasquon Italo , Villa Pier L. 
Published: July 2010

AbstractThe deactivation of a 0.5% ruthenium‐alumina catalyst for the methanation reaction has been studied at 250 and 400 °C in the absence and presence of small concentrations of hydrogen sulphide (H2S). The adequacy of a suggested mechanistic model for the methanation reaction has been confirmed and the model has been applied to the deactivation in the absence of H2S, which is significantly improved with respect to an empirical methanation rate equation. The effect of the presence of 10 mg dm−3 H2S in the reactant stream on the catalyst deactivation rate has also been investigated.
Dimensional stability of glass‐ionomer cements
Authors: Hornsby Peter R. 
Published: July 2010

AbstractFactors influencing the shrinkage behaviour of glass‐ionomer cements are described, with particular reference to the effects of cement age and the binding of water contained in the matrix. Dimensional changes occurring in cements exposed to alternating dry and saturated conditions are shown to be irreversible and a linear relationship is depicted between shrinkage and volume fraction of matrix. A failure mechanism involving matrix shrinkage is proposed to explain mechanical property changes which are evident when cements are maintained in environments of low relative humidity.
The thermal degradation of zinc O,O‐dialkyl phosphorodithioates and related compounds in petroleum media. Part 1. Zinc O,O‐diisobutyl phosphorodithioate
Authors: Ellis Raymond J. , Lake Peter J. , Marshall Roger A. G. 
Published: July 2010

AbstractThe thermal decomposition of zinc O,O‐dialkyl phosphorodithioates is acknowledged to play a significant part in their activity as multipurpose lubricating oil additives. Therefore, the isobutyl derivative in pentadecane solution has been degraded in a novel apparatus under a nitrogen atmosphere. The principal volatile products were found by gas‐liquid chromatography and mass spectrometry to be O,O,S‐triisobutyl phosphorodithioate, isobutanethiol and isobutene. In addition to these volatile products a solid (insoluble in organic solvents) was formed. This contained virtually all the zinc in the original reactant and had a zinc: phosphorus ratio of 2:3. It also contained carbon, hydrogen, sulphur and oxygen but the proportions of the latter two elements were unreliable. Variation of the period of heating, the temperature from 176 to 240°C and the concentration of the reactant from 1.4 to 7.0 × 10−2M affected the relative proportion but not the nature of the products formed. An equation involving the reaction of two molecules of the reactant has been written but kinetic data is required in order to establish a mechanism.
Hydrolysis of friedel—crafts reaction products at different temperatures
Authors: Barnes D. Ian , Robinson J. Gordon , Marr George 
Published: July 2010

AbstractToluene was reacted with propionaldehyde in the presence of aluminium chloride and the yields of the different products obtained were found to be dependent on the end temperature at which the hydrolysis was carried out. Most of the compounds identified in the reaction product were obtained in lowest yield when the hydrolysis was carried out at 87°C.
A problem in the production of defluorinated phosphate
Authors: Deutsch Yoetz , Sarig Sara 
Published: July 2010

AbstractIn Israel the phosphate industry produces amongst other products, defluorinated phosphate. The rock is heated to more than 1400°C with additions of phosphoric acid, soda ash, silica and steam. Occasionally not all the fluorine volatilises from the phosphate rock. It was proved statistically that the volatilisation of fluorine was incomplete whenever the concentration of zinc in the product (and presumably therefore the raw material) was relatively high. Experiments in the laboratory simulating the industrial process confirmed this.
Properties of hydroxyapatite prepared by the hydrolysis of tricalcium phosphate
Authors: Monma Hideki , Ueno Seiichi , Kanazawa Takafumi 
Published: July 2010

AbstractNon‐stoichiometric hydroxyapatite was prepared by the hydrolysis of α‐tricalcium phosphate. The apatite was obtained as a powder and hardened with and without stirring during the hydrolysis. The apatite had a general formula, characteristic dehydration and pyrolysis behaviour similar to that of precipitated non‐stoichiometric hydroxyapatite. In addition, it exhibited some new phenomena (i.e. thermal reaction between lattice H2O and PO43− above 473 K, formation of ESR centres above 473 K and disappearance at 873–973 K, and a slight weight loss at 873–973 K). Apatite particles were composed of aggregates of cylindrical rods or thin blades grown along the c‐axis or {100} faces of apatite structure. Hardened apatite materials with various porosities above 55% and bulk densities below 1.4 g cm−3 were obtained by using different water‐soluble additives. The strength of the hardened materials was 20–500 kg cm−2 in compression and 10–120 kg cm−2 in bending. The strengths were improved at least two to three times by impregnating the hardened materials with methyl methacrylate polymer.
Preparation of gelatinous aluminium hydroxide from aqueous solutions of organic aluminium salts by reaction with alkali
Authors: Sato Taicho , Suzuki Misao , Ikoma Shuji 
Published: July 2010

AbstractThe preparation of gelatinous aluminium hydroxide from aqueous solutions of the formate, citrate or tartrate of aluminium on addition of aqueous sodium hydroxide has been investigated under different conditions. The precipitates from aqueous solutions of aluminium formate consist of amorphous aluminium hydroxide, pseudoboehmite, bayerite, hydrargillite or their mixtures, depending on the condition of preparation. A mixed solution of aluminium citrate and sodium hydroxide yields no solid‐phase product without aging on heating to enhance the hydrolysis of aluminium citrate. The resulting precipitate exists as pseudoboehmite, independent of the preparation conditions. In contrast, aluminium tartrate is not hydrolysed to precipitate aluminium hydroxide even by aging on heating.
Sorption in porous crystals: Equilibria and their interpretation
Authors: Barrer Richard M. 
Published: July 2010

AbstractIn porous rigid zeolite crystals intracrystalline pore volumes are sub‐divided into regular channels and cavities of molecular dimensions only, and the total pore volumes can be determined. A consequence is that both absolute and Gibbs excess sorptions can be measured, examples of which have been considered. The Clapeyron‐Clausius equation is derived using solution thermodynamics so that isosteric heats should strictly be derived from absolute sorption isotherms. Consequences of using the equation to give corresponding heats for Gibbs excess sorption isotherms are considered, and the two heats compared for several systems. With the minimum assumption that mean hydrostatic stress intensity and mean concentration of intracrystalline sorbate can be related by a virial equation, the corresponding virial sorption isotherm correlates sorption measurements and gives equilibrium constants and thermodynamic data, which have been exemplified for particular systems. Model isotherms can also have limited applicability and can give information at a molecular level. Model isotherms in the presence of interaction between adjacent pairs of guest molecules have been considered with particular reference to the behaviour of binary mixtures.
Interactions between an alga and three bacterial species in a consortium selected for photosynthetic biomass and starch production
Authors: Lee Yuan‐Kun , Pirt S. John 
Published: July 2010

AbstractA four‐membered consortium (MA003) of an algal species and bacteria was selected from a natural source for its ability to grow at 37°C and produce starch photosynthetically from carbon dioxide. The photosynthetic culture consisted of a Chlorella‐like green alga (A003) and three heterotrophic bacteria, Alcaligenes sp. (B001), Flavobacter sp. (B002) and Serratia sp. (B003). The substrates for the bacterial growth were probably organic nitrogen and carbon compounds excreted by the alga at specific rates which were independent of the algal specific growth rate. The maximum specific growth rate of the alga was decreased by an inhibitor produced by bacterium B002. Bacterium B001 removed the inhibitor of algal growth released by bacterium B002, and bacterium B003 decreased the growth of bacterium B002 and consequently the production of algal growth inhibitor. The growth of bacterium B003 was greatly suppressed in the four‐member consortium MA003. The coexisting bacteria in toto, did not affect the growth rate, yield and starch production of the algal member, but did help to establish a stable ecosystem and increase the biomass available. A culture density up to 36 g dry weight dm−3 was achieved without significant variation in the ratio of the species in the culture.
Antibiotics from the newly isolated Streptomyces elizabethii. II. Isolation and characterisation of the antibiotics
Authors: Bird Clive W. , Latif Muhammad 
Published: July 2010

AbstractThe principal antibiotics formed by Streptomyces elizabethii have been isolated and identified as actinomycins IV and V, together with a methylpentaene macrolide, elizabethin, stereoisomeric with previously reported compounds.