bluuebunny/crossref_metadata_2025 huggingface dataset:
Macro‐scale modelling of substrate removal kinetics in multicomponent fixed‐film systems
Authors: Tanik A. , Orhon D. , San H. A.
Published: July 2010

Design of aerobic fixed‐film systems is generally performed using a traditional chemical reactor theory which accounts for changes in both substrate and biomass concentration. As most of these systems do not behave as ideal reactors, the theoretical evidence clearly shows that the variation and impact of biomass cannot be accounted for by a single reactor concept. Refinements reported in the literature concerning the fate of soluble substrate are modified in this study to also include the variation of biomass viability for different substrate concentration along the aerobic reactor. Evaluations show that a multi‐stage modelling biofilm performance is likely to be a much more reliable predictive tool for removal efficiencies.
Use of red mud for toxic metals removal: The case of nickel
Authors: Zouboulis Anastasios I. , Kydros Konstantinos A.
Published: July 2010

The presence of red mud was found to remove effectively nickel ions from dilute aqueous solutions (50 mg dm−3). Red mud, being an industrial solid by‐product/waste from alumina production during bauxite processing, was found to act simultaneously as an alkalinity regulator, causing precipitation of nickel as the insoluble hydroxide, as an adsorbent of the formed nickel hydroxide and as a flocculant of the resultant fine particulate matter. Sedimentation was subsequently considered as a possible solid/liquid separation technique. Various parameters, such as dispersion pH, red mud and nickel concentrations and ζ‐potential, were examined and promising results were obtained.
Application of ‘forward mixing’ model to the low interfacial tension system n‐butanol—succinic acid—water in rotating disc contactor liquid extraction columns
Authors: Korchinsky Walter J. , Bastani Daryoush
Published: July 2010

Previously published techniques for acquisition of experimental data, with dispersed phase hold‐up, drop size distributions and solute concentration profiles measured for all runs, and for generation of the relevant ‘forward mixing’ model parameters, have been applied to the low interfacial tension, high dispersed phase viscosity, system n‐butanol—succinic acid—water. The data, and generated parameter values, were consistent with previous data for toluene—acetone—water, with the main exception being the change in distribution of mass transfer resistances predicted by the Handlos—Baron model. Though overall mass transfer coefficients generated were of the same order as for the toluene—acetone—water system, the dominant resistance was predicted to be in the dispersed, rather than the continuous, phase. The influence of dispersed phase viscosity is incorrectly predicted by the Handlos—Baron model, which must be modified, or replaced, to correctly predict this influence. Data on other systems, with viscosity intermediate between the two systems used to date, are to be obtained. Continuous phase axial mixing influences are much higher than predicted by published correlations.
Application of five‐state structured models for growth and secondary metabolite production in cultures of Nicotiana tabacum
Authors: Shibasaki Naomi , Yonemoto Toshikuni , Tadaki Teiriki
Published: July 2010

A new structured model was constructed and applied to batch suspension cultures of Nicotiana tabacum in an airlift bioreactor with a draught tube. This model was developed by modifying the structured model proposed by Bailey and Nicholson1,2 for cultures of Catharanthus roseus cells. In this model, a plant cell was considered to consist of a vacuole and non‐vacuole. A secondary metabolite was also assumed to be synthesized by viable cells and stored at a constant concentration in the vacuole. Parameters for the model equations were estimated based upon experimental data using numerical optimization techniques. The simulated results using these parameters showed that the present model was superior to the earlier model for describing growth and product synthesis during all culture periods for the tobacco cell cultures.
Adsorption of disperse dye by various adsorbents
Authors: Lin Sheng H.
Published: July 2010

Laboratory investigations of C.I. Disperse Red 60 adsorption on molecular sieves, activated alumina, granular activated carbon (GAC), diatomite and sawdust were conducted in this study. The effectiveness of those adsorbents for pollutant removal and color reduction of disperse dye was examined and compared with that of powdered activated carbon (PAC). It was found that the activated alumina has only 61% COD removal efficiency in comparison with that of PAC while those of molecular sieves, GAC and diatomite are much lower. In terms of color removal, activated alumina and molecular sieves are as effective as PAC while GAC, diatomite and sawdust are much less effective. The monolayer Langmuir isotherm was found to represent well the measured adsorption data and the constant parameters of the adsorption isotherm were determined for all adsorbents. The simplified mass transfer model proposed previously was also used for estimating the mass transfer coefficients using the initial adsorption data for several adsorbents.
An automatic dehydrogenase‐based flow‐injection system: Application for the continuous determination of glucose and lactate in mammalian cell‐cultures
Authors: Becker T. , Schuhmann W. , Betken R. , Schmidt H.‐L. , Leible M. , Albrecht A.
Published: July 2010

A concept for the development of an automatic flow‐injection analyzer with integrated dehydrogenase columns and its application in the control of industrial processes is presented. The system is based upon a kernel consisting of a nested‐loop injection unit, pumps for the filling of the injection loops and the transport of buffer and valves for switching on the one hand between sample and standard solutions and on the other hand between different enzyme columns. A Microsoft Windows 3.x application ‘WIN‐FIA’ controls interactively the whole system and can be easily adapted to a specific solution of an analytical problem. As an example, the flow‐injection system was used for the continuous determination of glucose and lactate, using glucose dehydrogenase (GDH) and lactate dehydrogenase (LDH) as indicator enzymes, in a mammalian cell‐culture fermentation process. The resulting concentration values are in good agreement with those obtained by discontinuously taken standard spectrophotometric enzyme assays.
Vegetable composts for sea water uranium extraction
Authors: Marzotto Armando , Montoneri Enzo , Savarino Piero , Viscardi Guido , Croatto Ugo
Published: July 2010

Composting wood or crop residues by the addition of tanneries sludge as nitrogen supplement yields products having lower polysaccharides and protein content, but higher relative concentration of lignin material than the starting mixture. When used as sea water uranium adsorbents, the compost products exhibit higher uranium uptake (3.0–100 μg g−1) than parent ligno‐cellulosic materials (0.3–9 μg g−1), thus achieving over 104‐fold uranium concentration relative to sea water. An additional distinguishing feature is the strong pH effect observed on uptake by products. The results are consistent with the expected change of parent lignin to lignin‐humus in the compost product.
Production of astaxanthin by Phaffia rhodozyma using peat hydrolysates as substrate
Authors: Martin Antonio M. , Acheampong Edward , Patel Thakor R.
Published: July 2010

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

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

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

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

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

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

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

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

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

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

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

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

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

An expression is developed for the passage of material through rotating cylindrical kilns or driers, relating the time of passage to the other important variables—slope, length, diameter, and rate of rotation of the kiln, feed rate and rill angle of the material. The expression is derived from fundamentals, and is in accord with previously published empirical relations. It is thought that the derivation will promote a better understanding of the mechanism of the movement of materials in rotary kilns and driers.
Design of packed distillation columns. III. Rectification film resistances in a packed column
Authors: Hands C. H. G. , Whitt F. R.
Published: July 2010

Data are presented which lead to the conclusion that the liquid‐film resistance was the controlling resistance in rectification of a binary system carried out in a particular packed column. This confirms the conclusion reached by other workers on similar packed columns.
Heat‐transfer coefficient of condensing vapours
Authors: Chu Ju Chin , Dmytryszyn M. , Tichy W. , Kubik K. C. , Smith O. L.
Published: July 2010

The original method employed by Wilson to eliminate the use of thermocouples embedded in the tube wall in evaluating the heat‐transfer coefficient of the condensing vapours is not fundamentally sound. A modified method on a more rigorous basis is presented.

It has been demonstrated theoretically that the heat‐transfer coefficient of a condensing vapour is a function of rate of heat only. The proposed method consists in varying the rate of flow of cooling water inside the condensing tube and the over‐all temperature difference to obtain the heat‐transfer coefficients at a constant rate of heat‐transfer. The over‐all temperature drop is varied by changing the pressure in the vapour space. The film coefficient is then calculated from the intercept of a plot of δ T/q against 1/(1 + 0.011t) V0.8.

The heat‐transfer coefficients of trichloroethylene, bromobenzene, nitromethane and n‐hexyl alcohol have been experimentally determined by the proposed method. The theory of the method was confirmed by plotting h0 against q; the slope was equal to‐1/3.

The heat‐transfer coefficients predicted from Nusselt's equation agreed with those determined experimentally for trichloroethylene and bromobenzene, but not with those for nitromethane and n‐hexyl alcohol.
Preparation of the polyaminoguanidines
Authors: O'Connor T. E. , Horgan K. , Reilly J.
Published: July 2010

Guanylazide nitrate (I) interacts with hydrazine, the reaction products varying with molar ratio of hydrazine to azide. With equimolecular quantities of reactants, cyanamide, hydrazoic acid, 5‐amino‐tetrazole (III) and some aminoguanidine are formed, but with higher proportions of hydrazine, diaminoguanidine and triaminoguanidine are the chief products.

Simple and rapid preparative methods for diaminoguanidine nitrate and triaminoguanidine nitrate are described.

Benzylideneaminoguanidine, unlike aminoguanidine, does not undergo hydrazinolysis, but in a replacement reaction gives benzylideneazine and aminoguanidine.
The quantitative removal of corrosion products from zinc
Authors: Stroud E. G.
Published: July 2010

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

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

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

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

Experimental results which have been obtained in the course of comprehensive investigations of the water‐vapour permeability, diffusion and sorption of organic film‐forming materials are summarized. These data are used for elucidating the mechanisms and inter‐relationships of the processes. The analysis is based on thermodynamic principles and the multimolecular theory of adsorption. It is shown that the moisture sorption/relative humidity curves agree with the B.E.T. (Brunauer, Emmett and Teller) adsorption equation up to about 90% R.H. The heat of sorption is found to be the same as the heat of liquefaction of free water. It is concluded that the moisture sorption is a result of hydrogen‐bond formation with hydrophilic radicals in the molecules of the solid plus van der Waals' forces. The number of adsorption sites per g. of solid is calculated. The entropies of sorption for the various materials are estimated to show the degree of order of the sorbed moisture as compared with ice.

Diffusion constants are derived from sorption‐ and desorption‐rate curves; an anomaly in some of the sorption‐rate curves is discussed. The activation energies of diffusion indicate that, with one exception, diffusion is a process of repeated vaporization and sorption; the energy required for ‘hole’ formation is relatively low except with polyvinyl chloride (PVC). Fick's law of diffusion is not applicable at medium and high R.H.s; it is probable that the rate of permeation depends directly on the vapour‐pressure difference and not on the concentration gradient, but it appears that quantitative calculation of sorption and desorption rates by the classical diffusion equation is not very sensitive to appreciable deviations from Fick's law. The derivations of the B.E.T. equations for multimolecular adsorption and for the free energy of sorption are given as Appendices.
Studies in the corrosion of metals occasioned by aqueous solutions of some surface‐active agents. I. Copper
Authors: Holness H. , Ross T. K.
Published: July 2010

The action of dilute aqueous solutions of representative anionic, cationic and non‐ionic wetting agents on sheet copper has been studied. Three types of water have been used—London tap‐water, distilled water and tap‐water softened by the zeolite base‐exchange process. The effects of varying the pH of the solutions from 2 to 12 and of temperature changes have been investigated.

Most of the anion‐active agents examined first coated the copper with a water‐repellent film which afforded protection to the metal with primary and secondary sodium alkyl sulphates and sodium alkyl aryl sulphonate, but not with sulphonated castor oil or triethanolamine lauryl sulphate. With the cationic agents no water‐repellent film was formed and only triethanolamine attacked the copper to any great extent. There was no obvious action with the non‐ionic agent.

In general, rise of temperature caused increased attack, but changes in pH of the solutions were without marked effect on the course of the corrosion.

All results have been expressed graphically and a mechanism is suggested.
The colorimetric determination of aluminium in water using ammonium aurin tricarboxylate
Authors: Rolfe A. C. , Russell F. R. , Wilkinson N. T.
Published: July 2010

A method is described for the colorimetric determination of aluminium in water using ammonium aurin tricarboxylate at a controlled pH. Reaction of iron is inhibited by the addition of thioglycollic acid to form ferrous thioglycollate which is colourless at the pH of the test solution (4.4). The test is sensitive to 0.3 μg. aluminium and satisfactory results have been obtained over a range of 0–20 μg. Anions and cations in amounts normally present in water do not interfere, but some interference is obtained with excessive quantities. Hexametaphosphate and pyrophosphate interfere but these can be removed by hydrolysis to orthophosphate.

The test can be applied to the analysis of various alkali products after conversion to sodium chloride if a calibration curve is prepared in the presence of the appropriate amount of sodium chloride.
The preparation of highly reactive chars from coal and their interaction with sulphur
Authors: Kramers W. J.
Published: July 2010

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

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

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

Tables are provided which enable the concentration of CO in an atmosphere to be estimated under any particular conditions.
Steric hindrance in acetamidomesitylene
Authors: Sachs Georg
Published: July 2010

The acetyl group of acetamidomesitylene is not split off either by acids or by alkalis under analytical conditions. A laboratory preparation of acetamidomesitylene is described.
Observations on the inefficacy of a desiccator in determining the moisture in coal
Authors: Belcher R. , Mott R. A.
Published: July 2010

During research on the indirect determination of moisture in coal, the authors examine the errors possible when using a desiccator, and study the relative values of various desiccants. They conclude that an ordinary desiccator, regardless of the efficiency of the desiccant it contains, is of little use in preventing absorption of moisture by the dried coal, and that it can be abandoned provided that the moisture dishes bear well‐fitting covers, and that the time between drying and weighing is reduced to a minimum.
Studies in the production of penicillin, respiration and growth of penicillium chrysogenum in submerged culture, in relation to agitation and oxygen transfer
Authors: Calam C. T. , Driver N. , Bowers R. H.
Published: July 2010

The submerged‐culture process for the production of penicillin by Penicillium chrysogeman was investigated in the laboratory. An attempt was made to determine whether there was any rigid relationship between the growth and respiration of the mould and the yield of penicillin, and whether the rate of transfer of oxygen to the liquid phase always limited the yield of penicillin. With these objects in view fermentations were carried out with different types of fermenter, concentrations of medium and strains of the mould. The results indicated that there was no rigid relationship between the various processes. This view was supported by a study of the effect of temperature on the different reactions. With any particular set of conditions, however, changes in the speed of stirring produced effects on growth, respiration and yield of penicillin which appeared to be related. This was doubtless due to the effect of changes in agitation on parallel but relatively independent processes. Our results suggest that the yield of penicillin depends mainly on the suitability of the agitation for its particular enzyme system, and that at present improvements can best be sought by empirical means. Fermenters and fermentation‐systems will show different responses to changes in conditions depending on which part of the enzyme system producing penicillin is limiting its production.
An improved type of vapour‐liquid equilibrium still
Authors: Thornton John D.
Published: July 2010

A design is presented for a new type of vapour‐liquid equilibrium still. This incorporates separate liquid‐ and vapour‐sample traps, the latter being vacuum‐jacketed. The apparatus has proved satisfactory for investigating the type of system encountered in the extractive distillation process, where heterogeneous condensates occur a few degrees below the equilibrium temperature.
Commercial production of polystyrene
Authors: Samaras N. N. T. , Perry E.
Published: July 2010

The commercial production of polystyrene is limited by engineering considerations of heat transfer rather than by rate of chemical reaction. Mass polymerization has been developed for batchwise and continuous operation. Suspension polymerization was developed to overcome the limitations of the mass process by reducing the heat‐transfer distances to small values and by keeping the reacting mixture at a low viscosity. Emulsion polymerization can be considered an extreme case of suspension polymerization in which the droplet size is less than Im̈.

A consideration of relative capital and conversion costs shows that there are not large differences between the three processes, and the final choice as to which plant to install is a matter of specific circumstances.

Future developments on commercial polystyrene operation will be directed toward reducing capital costs required.
Copolymerization
Authors: Melville H. W. , Bonsall E. P. , Valentine L.
Published: July 2010

The mechanism of the copolymerization of two components in addition‐polymerization has been examined in detail for the systems styrene‐methyl methacrylate, styrene‐butyl acrylate, and styrene‐p‐methoxystyrene. In such reactions nine elementary‐radical processes are involved. By kinetic analysis of the problem combined with measurements of the rate, composition, and molecular weight of the copolymers and measurements of the rate‐coefficients for the polymerization of individual components, all the nine rate‐coefficients may be determined with reasonable accuracy.

One of the unusual factors which comes out of this study is that in the reaction of methyl methacrylate and butyl acrylate the velocity with which dissimilar radicals interact with each other is very much greater than the geometric mean reactivity of the separate radicals. On the other hand with the p‐methoxystyrene system completely normal behaviour is obtained and the rate of the interaction of dissimilar radicals is exactly equal to the geometric mean of the reactivity of the separate radicals.
Mineral oil as a wool lubricant; emulsification of blends of mineral oil and wool‐wax alcohols
Authors: Truter E. V.
Published: July 2010

Wool wax contains alcohols which, when mixed with a suitable mineral oil, give blends that are stable at 0° c. and are easily removable from wool. The flash points are well above the necessary minimum laid down by the fire insturance companies (340° F.), and there is no tendency for spontaneous oxidation to take place, nor do the blends become discoloured if exposed to very strong light for considerable periods of time. The isolation of these alcohols from several sources is described, and data on their performance are given.
Developments in the theory of cationic polymerization
Authors: Plesch P. H.
Published: July 2010

The polymerization of olefins by metal halides is discussed with special emphasis on the role of the co‐catalyst in these reactions. A new extension of the existing theory is proposed to account for some hitherto inexplicable observations, especially those relating to the effect of hydrogen halides on various polymerization systems. It is suggested that the carbonium ion which starts the polymerization may be formed by either of two essentially different reactions, depending on the nature of the catalyst, co‐catalyst and monomer. In one class of reactions the monomer reacts with a catalyst/co‐catalyst complex in the other the co‐catalyst reacts with a monomer/catalyst complex. In both cases a carbonium ion and a complex anion are formed.
Dynamic testing of road constructions
Authors: Van Poel C. Der
Published: July 2010

The deformations of various roads under alternating load were measured. The amplitude of the loading force ranged from 300‐2000 kg.‐force, and the frequencies from 5‐60 cycles/sec. The results give a good impression of the mechanical rigidity of the constructions and of the stresses and strains raised in the carpet.

In addition, the rates of propagation of the vibrations were measured at various frequencies. From these rates the dynamic Young's moduli of the various construction layers could be accurately calculated.
X‐ray investigation of 2 : 2′‐dihydroxy‐5 : 5′‐dimethyl‐diphenylmethane and its 3‐, 4‐, and 5‐ring polymers and p‐cresol novolak resins
Authors: Hunter R. F. , Vand V.
Published: July 2010

The X‐ray diffraction of 2 : 2′‐dihydroxy‐5 : 5′‐dimethyldiphenylmethane and its 3‐, 4‐, and 5‐ring polymers, two p‐cresol‐formaldehyde resins of known average molecular weight, and the 1 : 1‐addition complex of the 4‐ring polymer and ethylene dichloride have been examined using a Frevel focusing camera of high resolving‐power. Each pattern of a crystalline individual, however, proved different from the others and the number of repeating units in the polymer chain of the p‐cresol series is insufficient to lead to regularities of the type observed in other homologous series. There is a definite change from the crystalline to the amorphous state on passing from the 4‐ring to the 5‐ring polymer and the latter gives a photograph showing that the compound is approaching the condition of p‐cresol—formaldehyde resins. No polymorphism was observed in specimens of 2 : 2′‐dihydroxy‐5 : 5′‐dimethyldiphenylmethane prepared by crystallizing from different solvents and by drying under different conditions.
The formation of scale from hard waters at temperatures below the boiling point
Authors: Howland A. H. , Simmonds W. A.
Published: July 2010

In order to obtain information on the mechanism by which scale is formed from natural waters at temperatures below the boiling point, an investigation has been carried out into the formation of calcium carbonate by the thermal decomposition of calcium bicarbonate solutions. It has been shown that the rate of formation appears to be unaffected by the presence of glass surface but is greatly increased by the presence of various finely divided materials, particularly calcium carbonate powder. A quantitative estimate of the influence of calcium carbonate surface has been obtained and it has been shown that its effect increases with increasing temperature.

The experimental results indicate that the thermal decomposition of calcium bicarbonate solutions may be represented by the relation where C represents the calcium concentration at a time t and GE is the equilibrium concentration. The quantity m is a function of the initial supersaturation (CI ‐ CE) and for the temperature range 75°‐90° c. is given by m = 1.99 × 10−8 (CI ‐ CE)2.5.

The experimental results have also been applied to the formation of scale from natural waters and graphs are supplied from which it is possible to calculate amounts of scale deposition under various conditions.
A modified method for the determination of total penicillin in procaine penicillin
Authors: Wild A. M.
Published: July 2010

A method is described for the chemical assay of total penicillin (salt) in procaine penicillin [penicillin (procaine salt)]. The method depends on the conversion of procaine penicillin to sodium penicillin [penicillin (sodium salt)] by precipitation with sodium silicotungstate, the sodium penicillin being assayed iodimetrically.
An electron‐microscope study of plasticized nitrocellulose
Authors: Ames J. , Sampson Avis M. D.
Published: July 2010

The surfaces of films of (a) castor oil plasticized (b) dibutyl phthalate plasticized and (c) unplasticized nitrocellulose were examined in the electron microscope, using an atomic‐replica technique. The castor oil‐nitrocellulose plastic was relatively granular in texture, whereas the remainder were almost structureless. No evidence of the presence of plasticizer could be obtained, and it is concluded that the degree of dispersion of the plasticizer is finer than the resolving limit of the microscope. Some possible plasticization mechanisms are discussed on the basis of the observations made.
The recovery of organic material from cobalt 1‐nitroso‐2‐naphtholate
Authors: Dargaville A. D. , Ingles D. L. , Polya J. B.
Published: July 2010

The decomposition of cobalt i‐nitroso‐2‐naphtholate by sodium hydrosulphite (dithionite) gives cobalt sulphide and I‐amino‐2‐naphthol in good yields. Attempts at the electrolytic oxidation of I‐amino‐2‐naphthol to I‐nitroso‐2‐naphthol were unsuccessful.
Rapid electrolytic method for the determination of zinc in aluminium‐zinc alloys
Authors: Norwitz George
Published: July 2010

A rapid and accurate electrolytic method is described for determining zinc in aluminium‐zinc alloys. The sample is dissolved in sodium hydroxide, and then sulphuric acid and hydrogen peroxide are added to dissolve the copper. The peroxide is destroyed by boiling, and the solution buffered with tartaric acid. The zinc, copper and iron are quantitatively plated out together and the zinc found by difference. Nickel, lead and tin interfere with the determination.
Colorimetric determination of copper in aluminium alloys
Authors: Shrager S. A. , Norwitz George
Published: July 2010

A very rapid method for the colorimetric determination of copper in aluminium alloys is described. The sample is dissolved in hydrochloric and nitric acids, and an excess of ammonia is added to precipitate the aluminium, iron and silica. The solution is diluted to 500 ml. and a portion is filtered and read with a colorimeter at 580 m μ. A small correction is necessary for samples containing nickel.
Continuous polycondensation : The development of a practical method
Authors: Sunderland E.
Published: July 2010

The fundamental features of polycondensation reactions which have a bearing on methods of production are discussed. It is deduced that where reversible heterogeneous reactions are involved a film reactor will provide optimum production‐conditions.

Laboratory work has confirmed this deduction in several cases, notably where the reaction is a polyesterification, as in the production of oil‐modified alkyd resins.

In the light of the laboratory results a factory‐scale production unit has been designed and the salient features of this unit are described.
The influence of oxygen upon polymerization reactions
Authors: Abere J. , Mark H. , Hohenstein W. P.
Published: July 2010

Investigations were carried out to measure the influence of varying initial concentrations of oxygen upon the rate of polymerization during the early stages of polymerization of styrene in toluene solution. Likewise, the viscosity‐average molecular weights of the polymers produced were determined and correlated with the changes of the amounts of oxygen initially present.

In order to evaluate properly the differences in the length of the inhibition periods caused by the varying amounts of oxygen added, polymerizations of styrene were first carried out in the absence of oxygen. No inhibition period was observed then. The influence of varying amounts of oxygen is shown by an appearance of inhibition periods, the length of which is dependent upon the initial oxygen concentration. The viscosity‐average molecular weights of the resulting polymers also are related to the same quantity. It too can be observed that the velocity of the reactions immediately following the inhibition period is dependent on the amount of oxygen added at the beginning of the reaction.

In accordance with evidence produced by other investigators it is assumed that formation of polyperoxides takes place during the inhibition period. All the observed experimental facts can be explained by this assumption. It also is assumed that the decomposition of these polyperoxides causes a decrease in the length of the inhibition periods by producing radicals which can start new polyperoxide chains. The increase in the rate of the polymerizations after the end of the inhibition period above the rate of a thermal polymerization is of course also due to the decomposition of the polyperoxides at that period of the reaction.

Thus it is proposed to change the equation, suggested by Bolland and Gee for the relationship between initial oxygen concentration and inhibition period to P = Kt + a where a is a factor dependent on the rate of decomposition of the polyperoxides during the inhibition period, as well as on possible side‐reactions consuming oxygen.
The influence of carbon smokes on the corrosion of metal surfaces exposed to flue gases containing sulphur trioxide
Authors: Kear R. W.
Published: July 2010

Further work has been carried out to assess the effect of the presence of carbon smokes on the corrosion of a mild‐steel surface by flue gases containing sulphur trioxide. The results obtained have confirmed the view that a peak rate in corrosion obtains at temperatures of 20‐45°c. below the dew‐point of the gas and that the presence of carbon smokes can profoundly affect the extent of corrosion. As the smoke concentration is increased from zero there is an initial increase in corrosion but eventually the dew‐point of the gases and their corrosive properties are substantially reduced.

Comparison of the behaviour of filtered and unfiltered smoke‐laden gases would indicate that carbon reduces the sulphur trioxide content of flue gases by a process of physical adsorption.
The spectrographic determination of hafnia in mixtures of hafnium and zirconium oxides
Authors: Kingsbury G. W. J. , Temple R. B.
Published: July 2010

A general method for the quantitative analysis of non‐conducting solids has been developed, and its application is described for the particular problem of the determination of hafnium oxide in mixtures of hafnia and zirconia over the concentration range 0.01‐55%. The advantage of the method is that not more than 10 mg. of the oxides is required for the preparation of the electrodes, the material being attached to the end of flat graphite electrodes by a drop of Bakelite varnish and excited by means of an impulse are of a new type.

A number of line pairs have been examined to discover the most suitable, and it has been found possible to obtain good results by the use of two, namely. A standard deviation of = 6% has been obtained by this method. Some estimations of the residual zirconia of very pure hafnium oxide have been made using the lines Zr II 2387. i8A., HfII 2385.78A.