bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ion‐exchange properties of some brown seaweeds from the indian coast
Authors: Mehta B. R. , Baxi D. R. 
Published: July 2010

AbstractIon‐exchange properties of five marine algal species, viz. Sargassum tenerrimum J. Ag., S. swartzii (Turner) C. Ag., Cystoseira indica (Thivy et Doshi) Mairh, Tur‐binaria conoides (Kuetz) and Padina pavonica (L) (Thivy et Taylor) have been studied and compared with those of alginic acid. The ion‐exchange property of these samples is found to be due mainly to their alginic acid and fucoidin content. Uptake of calcium ions from different solutions and pH titration studies have revealed that the ionogenic groups present in the samples are dissociated to the extent of 35–50% even in neutral media. When subjected to continuous use, the ion‐exchange capacity of the weeds at first decreases but attains a constant value after a few cycles. The rate of exchange (H+→Na+ and H+→Ca2+) on these samples has also been investigated. Distribution coefficients (Kd) of some of the metal ions for the said species have also been determined and the affinity sequence of the metal ions for each of the samples has been given. Na+→Ca2+ and Na+→Mg2+ exchange equilibria gave abnornal exchange isotherms. However the separation factor 7alpha;Ca2+ is found to be an exponential function of the concentration ratio of the Na+/Ca2+ in the solution.
Improved power supply unit and current regulator for glow discharge electrolysis
Authors: Denaro Alfred R. , Davies Norman J. , Wood Alexander , Almubarak Mehdi A. 
Published: July 2010

AbstractAn improved combined rectifier and current regulator circuit for use in glow discharge electrolysis is described. Initiation of electrolysis will be obtained normally by switching on the primary high voltage supply and restricting the initial discharge current to less than 750 μA. As soon as this current is indicated, the required preset stabilised current can be switched on and accurately timed. Precise stabilisation of the current enabled the quantity of electricity passed in very short electrolyses to be measured with accuracy.
Thermal decomposition of iron sulphates. II. Mechanism of isothermal decomposition of FeSo4·H2O in carbon monoxide
Authors: Huuska Matti , Koskenlinna Markus , Niinistö Lauri 
Published: July 2010

AbstractThermal decomposition of FeSO4·H2O in carbon monoxide has been studied at 400–550°C by isothermal experiments. The reaction intermediates and products were identified by X‐ray diffraction and Mössbauer spectrometry and determined quantitatively by chemical analyses. In addition to the primary reduction of iron(II) sulphate to sulphide, a competing solid‐state reaction between FeS and FeSO4 takes place, leading to a loss of sulphur which amounts to about 25% at 420–460°C and to over 60% at 550°C. The final reaction products consist mainly of iron(II) sulphide and elemental iron. Enthalpies of the decomposition reactions are also briefly discussed.
The low gas flow rate foam separation of cerium (III) from dilute aqueous solutions
Authors: Shakir Kamal , Aziz Mourad 
Published: July 2010

AbstractTwo low gas flow rate foam separation techniques, ion and precipitate flotation, have been investigated for the separation of trivalent cerium from solutions with initial cerium concentrations ranging from 1 × 10−8 to 1 × 10−4M in the pH range of 1.8–12 using the anionic collector sodium lauryl sulphate and the cationic surfactant cetyl trimethyl ammonium bromide. In addition to the type of collector, the pH and the cerium ion concentration, and other factors which can affect flotation results, viz. the time period of bubbling, the rate of gas flow, the ageing of both the cerium and the collector ions, the ionic strength, and the concentration of the collector ions have been investigated and optimum conditions have been established. Under optimum conditions removals as high as 98.5% can be achieved.
Thermal treatment of Aerosil OX50: Pore structure and heats of immersion
Authors: Mikhail R. Sh. , Khalil A. M. , Nashed S. 
Published: July 2010

AbstractDegussa Aerosil OX50 was thermally treated in vacuo, in the temperature range 20–1000°C. Effects of thermal treatment on the water contents, specific surface areas, pore structure and heats of immersion in water were investigated and discussed. Thermogravimetric analysis was used to select the temperatures of thermal treatment which reflect the various textural changes resulting from the heat effects. It could be shown that the heats of immersion in water depend on both the water content of the sample (molecular water and/or surface hydroxyls) and on the surface texture of the silica gel, that is, the pore structure. The interesting result obtained is that the heat of immersion in water is partly proportional to the mesopore fraction of the surface. Micropores lead to a decrease in the heat of immersion in water.
Grindability of some additions and its significance in the production of mixed cements
Authors: Hanna Kaissar M. , Afify Aly 
Published: July 2010

AbstractGrinding tests were conducted in a laboratory steel ball mill, to investigate the grind‐ability of some natural and artificial materials as “additions” for incorporation in Portland cement. Strength tests were performed on mixed cements composed of 71% Portland cement clinker, 25% addition and 4% gypsum. In one series of experiments, the components of the mixed cement were separately ground and in another one they were simultaneously ground. It was found from surface production curves and from compressive strength data that when materials which are harder to grind than clinker such as sand are interground with clinker, the resulting cement develops higher early strength than a corresponding cement in which the pozzolanic addition is softer than clinker. For materials which are softer to grind than clinker, separate grinding of the cement components is better than combined grinding, particularly for the development of early strength.
Effect of moisture content of raw materials on the viscosity of limestone–marl slurry
Authors: Hanna Kaissar M. , Gamal Ahmed El 
Published: July 2010

AbstractViscosity measurements were performed to investigate the effect of moisture contained in Portland cement raw materials on the flow characteristics of limestonemarl slurry. Under conditions of constant total water content, the fluidity of the slurry increased as the moisture content of the raw materials decreased. The effect of moisture content of the raw materials becomes significant on reducing the water content of the slurry. In the presence of slurry thinners, the extent of deflocculation is greater with the raw materials of lower moisture content.
Studies on sodium silicate solutions by the method of trimethylsilylation
Authors: Glasser Lesley S. Dent , Lachowski Eric E. , Cameron G. Gordon 
Published: July 2010

AbstractThe method of trimethylsilylation was used to study anion distributions in sodium silicate solutions with Na2O: SiO2 ratios of 1:1 and 1:3.41 at various concentrations. The polysiloxanes produced were characterised, mainly by g.l.c., g.p.c. and C and H analyses, to give a picture of the anion distribution in the original solution. The results were compared with those from previous studies. The observations of earlier workers—that the degree of polymerisation increases with increasing concentration and decreasing soda:silica ratio—were confirmed.
Production of food yeast from whey ultrafiltrate by dialysis culture
Authors: Lane Alan G. 
Published: July 2010

AbstractYeast (Kluyveromyces fragilis) concentrations up to 90 g dry weight/litre were obtained by dialysis culture in an 8 litre fermenter and the concentrations of lactose in the whey ultrafiltrate reservoirs were reduced to 5–8 g/litre during the cultivation period. A marked and progressive fall in cell yield was observed as the concentration of yeast increased. Modelling experiments indicated that this fall was consistent with the effects of maintenance energy requirements and that the effect could be minimised by a four‐fold increase in the rate of dialysis. The feasibility of achieving the required increase with improved membranes was confirmed in experiments in which the rate of dialysis using existing membranes was shown to be doubled by either prior enzymic hydrolysis of the lactose or by doubling the membrane area.
Electrogenerative chloro‐ and bromo‐fluorination of olefins from aqueous media; the electrogenerative cell as a chemical reactor
Authors: Langer Stanley H. , Miller Alan D. , Pietsch Stephen 
Published: July 2010

AbstractFluoride ion can be discharged in conjunction with chloride and bromide ions under electrogenerative conditions at catalytic porous platinum electrodes to give dihaloalkanes. The cell C2H4(g), Pt black|KF, KCl (aq, barrier electrolyte)|Pt black, Cl2(g) gave 2‐chloroethanol, 1,2‐dichloroethane and 1‐chloro‐2‐fluoroethane (I); a similar cell gave 1‐bromo‐2‐fluoroethane (II) and analogous products with a platinum or carbon black anode and fluoride‐bromide electrolyte. While the yield of fluorinated compounds is low, they are prepared under very mild conditions. The electrogenerative cell can be operated to yield a variety of halogenated products in addition to (I) and (II).
Estimation of productivities in repeated fed batch cephalosporn fermentation
Authors: Trilli Antonio , Michelini Verardo , Mantovani Vera , Pirt S. John 
Published: July 2010

AbstractThe theory of fed batch culture was tested on the cephalosporin C fermentation. In repeated fed batch culture a constant fraction of the culture volume is removed at fixed intervals. Since the productivity (output rate/unit volume) and specific rate of product formation may vary throughout the fed batch cycle, an “average productivity” and “average specific rate of product formation” which describe the overall behaviour of the system over several cycles are introduced. The test shows that the quasi‐steady state of cephalosporin production predicted by fed batch theory can be maintained during at least 3.6 culture volume changes. The fed batch method of culture increased the productivity of the culture about 1.3 times with respect to that of simple batch culture whilst the cephalosporin C concentration was about the same in each type of culture.
Study of thermochromic behaviour of some indolinobenzospiropyrans by infrared spectroscopy
Authors: Bertoluzza Alessandro , Concilio Carlo , Finelli Paola 
Published: July 2010

AbstractThe thermochromic behaviour of some indolinobenzospiropyrans was studied by heating solid compounds in K Br. Changes in i.r. spectra are interpreted as being due to the formation of a pseudoquinonic structure, (V).
Thermal conductivity and viscosity of normal C2–C6 aliphatic carboxylic Acids
Authors: Kynaston Walter , Martin John F. 
Published: July 2010

AbstractEquipment for measurements of thermal conductivity and viscosity of liquids in the temperature range 273–350 K and at atmospheric pressure is described. The thermal conductivity and viscosity of acetic, propionic, butyric, valeric and hexanoic acids in the liquid state have been measured. The values obtained are compared with published data and the ratio of thermal conductivity, λ, to viscosity, η, is examined in the form of the dimensionless quantities, Mλ/Rη and cpη/λ (Prandtl number).
A phase model for the gas–liquid equilibria in the ammonia–carbon dioxide–water–urea system in chemical equilibrium at urea synthesis conditions. II. Experimental verification
Authors: Lemkowitz Saul M. , Vet Eric , van den Berg Pieter J. 
Published: July 2010

AbstractBubble‐ and critical‐points in the ammonia–carbon dioxide plane and ammonia–urea system are presented as well as bubble‐points in the carbon dioxide–urea system. In order to confirm the form of a previously presented phase model a large number of bubble‐ and dew‐points were measured at various ammonia–carbon dioxide–water–urea compositions (including those most important to the urea industry) in the range of 140 ⩽T⩽ 200°C and 15 <P< 400 atm. All of the measurements were carried out under conditions of complete chemical equilibrium. The results are in agreement with the ternary phase model presented in a previous article.
A phase model for the gas‐liquid equilibria in the ammonia‐carbon dioxide‐water‐urea system in chemical equilibrium at urea synthesis conditions. III. Comparison of the phase model with an empirical thermodynamic model
Authors: Lemkowitz Saul M. , Verbrugge Peter , van den Berg Pieter J. 
Published: July 2010

AbstractCalculations using an empirical thermodynamic model for the ammonia‐carbon dioxide‐water‐urea system in chemical equilibrium lead to phase equilibria results consistent and in good agreement with those following from a previously published ternary phase model for this system.
Coating of finished flax particle boards with insoluble gelatin
Authors: Fadl Naim A. , Sefain Magdi Z. 
Published: July 2010

AbstractCoating of finished flax particle boards with gelatin only, did not improve the resistance of boards to hot water. Coating with gelatin rendered insoluble, however, using hexamine and high temperature produced an insoluble gelatin film on the flax particles, which improved water resistance of the coated boards. Particle boards coated with 5% gelatin and a high concentration of hexamine (10%), improved water resistance to about 50% higher than that of uncoated samples. Higher amounts of gelatin (7.5 and 10%) gave a smaller improvement. The changes in thickness and density of the coated samples were also investigated.
Preparation of tricalcium phosphate by hydrolysis of dicalcium phosphate with calcium hydroxide
Authors: Bhavnagary Haiderali M. , Venugopal Jagadapur S. , Majumder Suvendu K. 
Published: July 2010

AbstractA hydrolysis reaction between dicalcium phosphate and calcium hydroxide has been investigated for the formation of tricalcium phosphate. It decreased steadily with the increase in aqueous dicalcium phosphate slurry concentration in the range of 0.5 to 1.25% under steam pressures of 5–25 lb/in2 and attained equilibrium at the concentration of 1.25% aqueous dicalcium phosphate. During the initial period of 2 h, the hydrolysis proceeded gradually to the respective maximums at the steam pressures of 15 and 25 lb/in2 and thereupon it was constant. It was also shown that 28.33% excess above the stoichiometric quantity of the hydrolysing agent, calcium hydroxide, was necessary for the complete hydrolysis to occur at the steam pressure of 25 lb/in2 for the aqueous suspensions of 5 and 25% dicalcium phosphate. The effect of increasing steam pressure showed that a complete conversion of dicalcium phosphate to tricalcium phosphate could be obtained at a steam pressure of 51.5 lb/in2 for any concentration of aqueous phosphate slurry.
Determination and correlation of diffusion coefficients of some dyes in organic solvents of high viscosity
Authors: Warren Brian C. H. , Pattle Richard E. 
Published: July 2010

AbstractDiffusion coefficients of three dyes at low concentrations in a range of liquids of different viscosities have been measured by a capillary method, and the validity of various empirical equations for predicting diffusion coefficients has been assessed. The inverse relationship between diffusion coefficient and viscosity was found to apply only in mobile liquids, the product Dη being greater in viscous liquids. For a given viscosity, the difference between predicted and experimental values was greatest for hydrogen‐bonded liquids. Comparison with other results suggests that the diffusivity varies inversely as some power of the molar volume of the solute, the exponent varying from about 0.7 for mobile liquids, through 1.1 to 1.4 for viscous liquids, to a literature value of 1.7 for solid rubber.
Ce(III), Th(IV) and U(VI) chelates of alizarin viridine, alizarin heliotrope and alizarin maroon
Authors: Idriss Kamal A. , Issa Issa M. , Seleim Mohamed M. 
Published: July 2010

AbstractThe complexes of 7,8‐dihydroxy‐1,4‐di(2′‐sulpho‐4′‐methylanilano)anthraquinone (alizarin viridine); 1,4‐dihydroxy‐2(2′‐sulpho‐4′‐methylanilino)anthraquinone (alizarin heliotrope) and 3‐amino‐1,2‐dihydroxyanthraquinone (alizarin maroon) with Ce(III), Th(IV) and U(VI) have been investigated using spectrophotometric and conductometric methods. The study revealed the formation of complexes having the metal: ligand ratios 1:1 and 1:2. The values of log β* for the different complexes are determined. The structure of the ligands in the solid chelates were studied by i.r. spectrophotometry which showed that chelate formation takes place through the CO and neighbouring OH group and leads to proton displacement.
Effect of various steps of purification on ash content and ash constitution of cellulose. II. Cellulose prepared from sugar‐cane bagasse
Authors: Shahine Salah , El‐Shorbani Salah , El‐Sadani Mohamed 
Published: July 2010

AbstractThe effect of the various steps of purification on the ash content and ash constitution of cellulose prepared from bagasse has been examined. After each step of purification, samples were analysed for total ash, SiO2, Ca, Fe and Mn. Two schemes of purification have been investigated. The first involves acid prehydrolysis, alkaline pulping and bleaching, and the second water prehydrolysis, acid pulping and bleaching. The first scheme has a better effect in diminishing the ash content, and gives a pulp containing 95.8% alpha cellulose with a 90% degree of whiteness.
Controlled pyrolysis of maleic hydrazide
Authors: Smith Walter T. , Mayer Charles F. , Kook Chyung S. , Patterson John M. 
Published: July 2010

AbstractMaleic hydrazide (MH) has been pyrolysed at 600°C in our controlled pyrolysis apparatus. During pyrolysis volatile compounds distil out ahead of the moving heated zone and are not extensively repyrolysed, while those substances which are absorbed by pyrolysand or are relatively nonvolatile are repyrolysed. Also, reactive intermediates can react with one another or with unpyrolysed material. Pyrolysis products determined include CO2 (24 wt%), CO (2 wt%), HCN (3 wt%), NH3 (9 wt%) and N2 (3 wt%). The gases identified account for 41 % of the maleic hydrazide pyrolysed. An additional 50% of the material pyrolysed remains as a black solid having the approximate composition C15H15N5O2. Approximately 1 % of the maleic hydrazide is unchanged. Thus, the fate of 92% of the maleic hydrazide can be accounted for. A trace amount of hydrazine could be detected. The results obtained using controlled pyrolysis are compared with results obtained by us and others using different pyrolytic conditions.
Determination of the O2 and CO2KLa values in fermenters with the dynamic method measuring the step responses in the gas phase
Authors: Schneider Kurt , Frischknecht Kurt 
Published: July 2010

AbstractSimulation studies using the mass balance equations demonstrate that it is possible to determine the KLa values for O2 and CO2 from measurements taken in the gas phase. In order to do this, the step change must be applied to the concentrations in the liquid phase. An injection device was developed to generate these step functions. The KLa values for O2 and CO2 measured in the presented system are of the same size. These values allow the theoretical step responses to be calculated, which are compared to the experimental ones. It is shown that the gas phase dynamic must be taken into account to avoid calculating KLa values with intolerable errors.
Saccharification of bagasse pith
Authors: Nee Charles I. , Yee Wen F. 
Published: July 2010

AbstractWork is reported here on a process for the saccharification of bagasse pith, as the second part of a study of bagasse processing aimed at establishing an integrated industry. A method for pentose preparation from bagasse pith is designed on the basis of the conclusions reached in the first part of the study. It is preferable to Scholler's process in recovery of sugar and in concentration of the sugar solution. A process for glucose production from pentose‐exhausted cellulosic residue is also developed to avoid the difficulties encountered in the Udic‐Rheinau process. It seems to be a promising continuous process capable of giving a higher yield of glucose with less acid at a higher speed and affording favourable conditions for crystallising the dissolved glucose.
Aspects of microbial physiology in relation to process control
Authors: Leegwater M. P. M. , Neijssel O. M. , Tempest D. W. 
Published: July 2010

AbstractThe innate ability of microorganisms to respond rapidly to changes in the growth environment has been termed ‘reactivity’ and is a property of most microbial species. This feature of microbial physiology is of importance in the culturing of microbial cells on a large scale where environmental heterogeneity is unavoidable and gradients of temperature, pH, oxygen and nutrient concentration can occur. To assess the consequences of such gradients, a study was made of the influence of a discontinuous addition of glucose to a glucose‐limited chemostat culture of Klebsiella aerogenes. Results revealed a marked and unexpected shift in metabolism with an increased capacity for glucose uptake and respiration. This increased reactivity enhanced the ability of K. aerogenes to compete with other species (e.g. Escherichia coli) in chemostat culture.
Development of downstream processing
Authors: Atkinson Bernard , Sainter Philip 
Published: July 2010

AbstractForeseen developments in biotechnology are likely to lead to a proliferation of processes for small‐tonnage products and a number of large‐scale operations providing alternatives to natural and petrochemical‐based products. Product recovery will become increasingly important and, possibly, a dominant factor in the overall cost. The primary stages of the recovery processes must handle dilute slurries from the fermenter at a low cost per unit slurry volume if the overall processes are to be economical. Available unit processes are identified and the type of developments likely to prove economical are discussed. Subsequent recovery stages are much more closely related to established process‐engineering technology and in this area the key decision is likely to be the choice of the most appropriate route from the alternatives which are available. Equipment development to bring some laboratory separation techniques to a production scale will probably be required.