bluuebunny/crossref_metadata_2025 huggingface dataset:
The growth of Aspergillus terreus and the production of itaconic acid in batch and continuous cultures. The influence of pH
Authors: Rychtera Mojmir , Wase D. A. John
Published: July 2010

Aspergillus terreus (NRRL 1960) was cultivated in batch and in continuous singlestage culture. The influence of pH on the growth of the organism, on the formation of itaconic acid and on the kinetics of fermentation was studied under phosphate limitation, both at controlled pH values and also when the pH was allowed to decrease in a natural way. In the pH range 1.7–3.5, the ratio of undissociated :half‐dissociated acid varied from 190:1 to 1.5:1. The amount of completely dissociated acid may be regarded as negligible. In batch systems operated without pH control, an initial pH of 3.1 proved to be the most effective. Product formation under such conditions started at a point where the exponential growth phase commenced and was described by a zero‐order equation. The maximum itaconic acid production rate was shifted behind maximum growth rate. The continuous single‐stage system was first order with respect to product formation. At pH > 3.1, a number of aberrant and pellet forms of the mould occurred, resulting in decreased acid production.
Cohesion energy densities and solubility parameters for the n‐alkanes expressed as a new homomorph equation
Authors: Wingefors Stig , Liljenzin Jan‐Olov
Published: July 2010

A new correlation formula for the calculation of the cohesive energy density for n‐alkanes and the corresponding homomorphs for polar solvents has been developed. Constants of the Antoine equation and literature values of heat of vaporisation at the boiling point and at 25°C were used. For the C2‐C16 n‐alkanes the new correlation equation describes the cohesion energy density as a function of molal volume and reduced temperature within the accuracy of experimental data. In the range of reduced temperatures 0.4 < Tr < 0.7 and molal volumes 50 < V <300 cm3 the maximum deviation for this fit is less than ± 0.05 J1/2 cm−3/2. In the region of Tr and V for polar homomorphs to the n‐alkanes at 25°C the deviations are typically less than half this value.
Mesophase from electrode‐binder coal‐tar pitch: An appraisal of structural techniques
Authors: Drake John A. G. , Jones Derry W. , Mason Clifford R.
Published: July 2010

An electrode‐binder coal‐tar pitch containing mesophase and resulting from combined mild thermal treatment under nitrogen and hot filtration (to remove ash, etc.) has been examined by solvent analysis and magnetic resonance (high‐resolution 1H‐nuclear‐magnetic and electron‐spin resonance) spectroscopy, X‐ray diffraction and polarised light microscopy. At ambient temperature, residues and filtrates with higher mesophase contents tend to exhibit higher concentrations of unpaired electrons and higher stacks in crystalline regions. Room‐temperature 100 MHz 1H‐n.m.r. spectra of solvent extracts of the treated pitch fractions confirm the predominance of aromatic over aliphatic hydrogen in all samples; heat‐treated samples have lower content of hydrogen α to the rings but greater amounts of methylene and methyl hydrogen more remote from the rings than before the heat treatment.
Adsorption of surfactants on rocks: Microcalorimetric approach applied to tertiary oil recovery
Authors: Rouquerol Jean , Partyka Stanislaw
Published: July 2010

Results obtained for the adsorption of surfactants (non‐ionic and ionic) on a ground sand (4.2 m2 g−1) and on a kaolin (19.4 m2 g−1) are described. The very small enthalpy of displacement of water by the surfactant molecules (5–17 mJ m−2 of adsorbing surface) and the slow structuring or rearrangement of adsorbed molecules (over several hours) would be extremely difficult to detect by techniques other than microcalorimetry.
Catalysis over bimetallic zeolites: Influence of copper on the catalytic behaviour of nickel in sodium and hydrogen Y zeolites
Authors: Coughlan Brendan , Carroll William M. , Abohalguma Ahmed
Published: July 2010

The catalytic activity of a range of bimetallic nickel/copper zeolite catalysts prepared from NaY and NH4Y as starting materials has been investigated; the reactions chosen were alkylation of toluene with methanol and the hydrogenation of benzene. The samples prepared from NH4Y did not reduce benzene although they contained metallic nickel; this is attributed to nickel migration and agglomeration. All the catalysts were active in alkylation and there is evidence that a Cu:Ni ratio of 3:2 favours the formation of intrazeolitic clusters and confers increased acidity on the catalysts.
Adsorption of metal cations on wool carbonising waste. Part 1. Adsorption isotherms
Authors: Farag Karim , Perineau Francis , Gaset Antoine , Molinier Jacques
Published: July 2010

The adsorption of various metal ions (Hg2+, Ag+, Ni2+, Cr3+, Al3+, Zn2+ and Pb2+) on wool carbonising waste has been investigated to assess its possible use as an adsorbent in water pollution control. Isotherms show that few metal ions (Hg2+, Ag+ and Ni2+) are adsorbed satisfactorily by this material. Moreover, the adsorption capacity of the plant material within the carbonising waste is higher than that of the keratin fraction. Equations fitting the experimental data can be used for the design of processing units.
Adsorption of ionic solutes on acidic lignin wastes
Authors: Perineau Francis , Gaset Antoine
Published: July 2010

The adsorption of surfactants and dyes on two kinds of agricultural wastes made up of acidic lignins has been investigated. One of the wastes displayed a strong affinity towards anionic solutes, whereas the other one was more efficient towards cationic solutes. These materials adsorb the organic solutes extensively. They may find use as adsorbents for the purification of industrial effluents.
Design models for adsorption systems in wastewater treatment
Authors: McKay Gordon
Published: July 2010

The application of mathematical models to the design of adsorption systems as a method of purifying wastewaters is considered. The design of batch, fixed‐bed, pulsed‐bed, moving‐bed and fluidised‐bed systems for effluent treatment is discussed. A brief review of the wide range of industrial effluents and adsorbents that may be utilised in such systems is considered. Reactivation procedures are presented and the principles of minimising design costs by optimising design are given.
Treatment of ammonium fluoride solutions in a semicontinuous fixed bed process
Authors: Ekdunge Per , Simonsson Daniel
Published: July 2010

A new process for the removal of fluoride from effluents containing ammonium fluoride is described. The defluoridation is based upon the reaction of the NH4F solution with coarse calcite particles. The special technical importance of this reaction is that the limestone grains are almost completely converted to calcium fluoride without losing their shape and size. A sludge‐free process is thus possible, and the CaF2 produced can be sold as a substitute for fluorspar. A semicontinuous fixed bed of limestone particles can reduce the fluoride content by about 95–98% in a single pass. After the recovery of CO2 and NH3 by distillation, the fluoride concentration can be reduced further to 10–20 parts/106 by acidification of the solution and repeated treatments in two secondary limestone columns.
Surface interactions of carbon dioxide and pyridine with LaCrO3 perovskite‐type oxide
Authors: Fierro José Luis G. , Tejuca Luis G.
Published: July 2010

The adsorption of CO2 on LaCrO3 in the temperature range 273–675 K was studied. The equilibrium data were analysed according to Freundlich's model. Firstly CO2 chemisorbs, producing irreversible species which were identified as bidentate carbonates (infrared bands at 1660, 1650, 1631, 1306, 1220 and 1106 cm−1). Then CO2 is reversibly chemisorbed as a free carbonate ion (infrared band at 1423 cm−1); the high coverages observed at lower temperatures suggest some participation of physical adsorption in the reversibly adsorbed CO2. Entropy calculations showed that these adsorbed species are best described by a mobile model which assumes two translational and two rotational degrees of freedom. Carbonates produced after CO2 adsorption on LaCrO3 are more difficult to remove than carbonates formed on LaCoO3. This provides a possible explanation for the low catalytic activity for CO oxidation of the former oxide as compared with the activity of the latter. After pyridine adsorption, Lewis bands in the infrared region at 1606, 1595, 1490, 1440 and 1220 cm−1 were observed. After adding water no Brönsted bands were found.
The synthesis of pyrazolo‐ and isoxazolo‐[3,4‐c]‐pyrazole hemiazadicarbocyanine dyes
Authors: Koraiem Ahmed I. M.
Published: July 2010

New substituted pyrazolo and/or isoxazolo‐[3,4‐c]‐pyrazole hemiazadicarbocyanine dyes (IVa‐d, Va‐d, VIa‐d) were prepared via the synthesis of 4‐arylidino‐1‐phenyl‐3‐benzoxazolium‐2‐yl‐pyrazol‐5‐one (IIa‐d) followed by their interaction with hydrazine hydrate, phenylhydrazine and hydroxylamine. Structures of the synthesised compounds were determined from analytical data and from spectra. The biological activity of IV, V and VI were tested against bacteria and fungi.
Production of xylose, furfural, fermentable sugars and ethanol from agricultural residues
Authors: Singh Amar , Das Kumudeswar , Sharma Durlubh K.
Published: July 2010

With the developing shortage of petroleum, reliance on biomass as a source of chemicals and fuels will increase. In the present work, bagasse and rice husk were subjected to dilute acid (H2SO4) hydrolysis using pressurised water to obtain furfural and fermentable sugars. Various process conditions such as particle size, solid‐liquid ratio, acid concentration, reaction time and temperature have been studied to optimise yields of furfural, xylose and other fermentable sugars. The use of particle sizes smaller than 495 μm did not further increase the yield of reducing sugars. A solid‐liquid ratio of 1:15 was found to be the most suitable for production of reducing sugars. Hydrolysis using 0.4% H2SO4 at 453 K resulted in selective yields (g per 100 g of dried agricultural residues) of xylose from bagasse (22.5%) and rice husk (21.5%). A maximum yield of furfural was obtained using 0.4% H2SO4 at 473 K from bagasse (11.5%) and rice husk (10.9%). It was also found that hydrolysis using 1% H2SO4 at 493 K resulted in maximum yields of total reducing sugar from bagasse (53.5%) and rice husk (50%). The reducing sugars obtained were fermented to ethanol after removal of furfural. The effect of furfural on the fermentation of sugars to ethanol was also studied. Based on these studies, an integrated two‐step process for the production of furfural and fermentable sugars could be envisaged. In the first step, using 0.4% H2SO4 at 473 K, furfural could be obtained, while in the second step, the use of 1% H2SO4 at 493 K should result in the production of fermentable sugars.
Synthesis and antibacterial activity of some new diarylsulphides and diarylsulphones containing azetidin‐2‐one and/or diazetidin‐2‐onyl moities
Authors: Abbady Mahmoud A. , El‐Kahef Hussein S. , Abd‐Alla Mohamed A. , Kandeel Maymouna M.
Published: July 2010

Cyclonucleophilic addition of N‐phthaloylaminoacid chlorides (II on 4‐(N‐ary‐lideneamino)‐4′‐nitrodiphenyl sulphides (I) in dioxane and triethylamine afforded 4‐(4″‐aryl‐3″‐phthalylamino‐2″‐oxo‐azetidin‐1″‐yl)‐4′‐nitro‐diphenyl sulphides (III). Hydrazinolysis of III yielded 4‐(4″‐aryl‐3″‐amino‐2″‐oxo‐azetidin‐1″‐yl)‐4′‐nitro‐diphenyl sulphide hydrochlorides (IV). Condensation of IV with anisaldehyde using ethanol and piperidine as a basic catalyst gave 4‐(4″‐aryl‐3″‐anisylidine amino‐2″‐oxoazetidin‐1″‐yl)‐4′‐nitrodiphenylsulphides (V) in good yields. Interaction of V with chloroacetyl chloride in dioxane and triethylamine produced 4‐(4″‐aryl‐3″‐substituted β‐lactamyl‐2″‐oxo‐azetidin‐1″‐yi)‐4′‐nitrodiphenyl sulphides VI. Oxidation of IV, V and VI using hydrogen peroxide/glacial acetic acid mixtures gave the corresponding sulphones (VII), (VIII) and (IX). Sulphones of the type IX were obtained by unequivocal synthesis through interaction of sulphone‐anils VIII with chloroacetyl chloride. The antibacterial activities of some of these compounds were determined.
The effect of inverted micelles adsorbed on different metals on the hydrolysis of methyl salicylate and ethyl acetoacetate
Authors: Iwunze M. O. , Nnodimele R.
Published: July 2010

Hydrolysis of methyl salicylate was carried out on inverted micelles adsorbed on copper. The initial rate of hydrolysis was found to be a linear function of the surfactant concentration and copper surface area. However, the initial rate was found to be linear only at low surfactant concentrations for a fixed surface area of copper, and reached a maximum at higher concentrations. Cetyltrimethylammonium bromide (CTAB) was found to be a better catalyst both in the ordinary micelle and in its inverted form than the corresponding Hyamine surfactant. The effect of different metals on the initial rate of ethyl acetoacetate hydrolysis was investigated. An enhanced rate of hydrolysis was observed on the selected metals used (Al, Cu. Pb and Sn) and the magnitude of the rate enhancement was observed to be dependent on the potential of zero charge (pzc) of these metals.
Correction factors for the dynamic measurement of the volumetric mass‐transfer coefficient
Authors: Spriet J. A. , Botterman J. H.
Published: July 2010

The experimental determination of the volumetric mass‐transfer coefficient based on the use of an oxygen electrode requires a mathematical model of the experimental system and a parameter estimation method to obtain a number for the kta value. Previous work has resulted in a number of different model structures corresponding to different hypotheses concerning the relevant physical phenomena. Little is known about the impact of a specific choice for the model structure or that of the estimation procedure on the numerical value of the mass‐transfer estimate. This impact is investigated here and guidelines are given for the choice of a parameter estimation scheme. In addition, correction factors that measure the impact of a structural choice are given for both the moment and least squares parameter estimation methods. The diagrams may be used in a preliminary phase to make an overall appraisal of the specific experimental conditions and in the estimation phase to reduce computational loads.
Permeation of benzene through liquid surfactant membranes
Authors: Goswami Amar N. , Rawat Bachan S.
Published: July 2010

The effect of time on the permeation of benzene through aqueous surfactant membranes formed with two non‐ionic surfactants has been studied on a batch scale under two different conditions of surfactant concentration and hydrocarbon: water ratio in the emulsions. The data have been correlated by an equation based on Casamatta's model of hydrocarbon permeation from an emulsion drop. The results indicate that the correlation can be used to treat the data until the onset of membrane rupture. The membrane thickness depends on the hydrocarbon: water ratio in the emulsion, and varies from about 1.57 to 5.10 μm.
Desiccant efficiency in solvent and reagent drying 8. molecular sieve column drying of 95% ethanol: An application of hygrometry to the assay of solvent water content
Authors: Burfield David R. , Hefter Glenn T. , Koh Donald S. P.
Published: July 2010

The use of hygrometry for the measurement of ethanol water content and the application of molecular sieves for column drying of 95% ethanol are described. The commercial hygrometer used in this study permitted measurement of water content in the range 0.005–5% (by vol) but was subject to a number of limitations which made measurements more time‐consuming than anticipated. Grossly wet ethanol containing 5% (by vol) water was readily dried to a water content of about 0.3% (by vol), by treatment with a column of 3A molecular sieves. Slow flow rates enhanced the drying action, which was largely independent of the column dimensions and scale of the drying process. Water breakthrough occurred when water adsorption by the sieves exceeds about 10% (by wt).
Kinetics of catalytic esterification of propan‐1‐ol with propanoic acid using cation‐exchange resin
Authors: Dakshinamurty P. , Ramarao M. V. S. , Ramachandramurty Ch. V.
Published: July 2010

The kinetics of liquid phase esterification of propan‐1‐ol with propanoic acid catalysed by Dowex‐50W cation‐exchange resin in the H+ form have been studied in a batch reactor. The effects of catalyst concentrations, mol ratios and temperatures on the conversion were studied. An empirical correlation relating the specific reaction rate constant in terms of these variables has been developed, and a mechanism proposed on the lines of the Langmuir‐Hinshelwood model. The effect of different catalysts on the conversion is compared.
Hydration of magnesium oxides in the presence of water vapour
Authors: Bhatti Asif S. , Dollimore David , Dyer Alan
Published: July 2010

The uptake of water vapour on to magnesium oxide has been studied using a silica spring technique. In the experiment reported here, porous magnesium oxides were investigated, and the amount adsorbed at equilibrium at various vapour pressures of water was determined. The magnesium oxides used were characterised using low temperature nitrogen adsorption to give a pore size distribution and a specific surface area, and chemical analysis from X‐ray fluorescence data. The nitrogen adsorption isotherms obtained were a mixture of type II and type IV using the BET classification. The oxides sorbed water vapour to give an equilibrium isotherm which was sigmoid in character. Rehydration of the samples after desorption and degassing at 298 K produced samples with an enhanced capacity for water vapour sorption. This is associated with a change in the surface of the oxide from a hydrophobic to a hydrophilic character upon the second adsorption cycle. This is of importance in assessing the water sorption capacity of industrial produced porous magnesium oxides and their subsequent use as desiccants.
Studies on an araldite‐based membrane of copper hexacyanoferrate (III) as a caesium ion‐sensitive electrode
Authors: Jain Ajay K. , Singh Raj P. , Bala Chand
Published: July 2010

Solid membranes of copper hexacyanoferrate (III) in araldite are evaluated as a caesium ion‐sensitive electrode. The electrode can be used for caesium determination in the concentration range of 10−1 to 10‐4M. The potentials generated across the membrane are reproducible and steady potentials are attained in about 1 to 2min. The same electrode can be used over a period of 6 months without significant change in potential. The electrode can be used in the pH ranges 2.5–6.0 at 10−2 M Cs+ and 3.0–6.0 at 10−3 M CS+, and in presence of a number of interfering ions. Potentiometric titration of caesium nitrate with 12‐moIybdophosphoric acid was also carried out using the membrane as an end point indicator.
Comparative study of the activity of cobalt and nickel as promoters of HDS catalysts
Authors: Laine J. , Severino F. , Golding R.
Published: July 2010

A series of trimetallic (NiCoMo) hydrodesulphurisation supported catalysts were prepared using a successive impregnation method, varying the ratio of promoters Ni/(Ni + Co) and maintaining the ratio (Ni + Co)/Mo constant. Optima for higher thiophene hydrodesulphurisation activity were found for ratios Ni/(Ni + Co) of 0.7 and 0.8. It is suggested that the optima may be strongly dependent on method of catalyst preparation, and/or type of support employed. Presulphidation was found to increase the activity in NiMo more than in CoMo. Testing of commercial catalysts confirmed various differences between CoMo and NiMo catalysts.
The kinetics of hydrodesulphurisation of thiophene over a nickel‐molybdenum catalyst
Authors: Sharma Nagesh , Chakraborty Purnanand , Kar Anil K.
Published: July 2010

The kinetics of vapour phase hydrogenolysis of thiophene over a series of unsupported and γ‐alumina supported nickel‐molybdenum catalysts were studied at atmospheric pressure using a fixed bed integral microreactor. A kinetic expression describing the effects of temperature and space velocity was experimentally verified. The hydrogenolysis of thiophene was found to be 0.8th order with respect to thiophene and 0.8Sth order with respect to hydrogen. The activation energy of the reaction over nickel‐molybdenum (NiO:MoO3 weight ratio 30:70) catalyst was found to be 19.23 kJ mol−1 in the temperature range 250–350°C, while above this temperature the reaction was affected by adsorbed thiophenic sulphur. X‐ray and infrared analyses of the catalysts indicated that MoO3 (Mo6+, a main component), which after pretreatment forms MoS2 or MoS2+MoO2, requires the incorporation of a specific concentration of nickel (Ni:Mo ca 0.5) in the form of α‐NiMoO4 for maximum hydrodesulphurisation activity.
The recovery of the lanthanides from phosphate rock
Authors: Habashi Fathi
Published: July 2010

Phosphate rock contains up to 1% lanthanide (rare earths) oxides present in isomorphous substitution for Ca2+. Lanthanum, cerium and neodymium form about 80% of the total. When the rock is leached with H2SO4 the lanthanides are mostly (about 70%) lost in the gypsum residue. When the rock is leached with HNO3 or HC1, more than 80% can be recovered without interference with fertiliser production. At an annual production of 130 million tons, phosphate rock represents an important source of lanthanides. The different methods of recovery are reviewed.
The extraction of platinum from Pt(II) chloride solution by a quaternary ammonium compound
Authors: Hoh Ying‐Chu , Chuang Wen‐Shou , Yueh Peng‐Shiung
Published: July 2010

The fundamental aspects of the extraction and stripping of platinum (II) from its chloride solution by Aliquat 336 diluted with toluene have been studied. The extraction and stripping was at 99.5 and 97.6% equilibrium within 30 s and 20 min respectively. The percentage extraction increased slightly with decreasing hydrochloric acid concentration. In 0.1 mol dm−3 hydrochloric acid, 1.0 volume percent Aliquat 336 in toluene could load 9.8 mmol dm−3 of platinum (II). The percentage stripping of platinum (II) from Pt(II)‐load organic solvent increased with increasing sodium bisulphite concentration. The enthalpy changes of extraction and of stripping were 12.8 and 114.9 kJ mol−1 respectively. Both of the reactions were endothermic.
A convenient preparative method for mintlactone and isomintlactone
Authors: Fujita Tsutomu , Watanabe Shoji , Miharu Kenji , Itoh Kazunori , Sugahara Kotoji
Published: July 2010

Various 2‐(2′‐hydroxy‐4′‐methyl‐1′‐cyclohexylidene) carboxylic acid lactones were synthesised in good yield from carboxylic acids and 4‐methylcyclohexanone. For example, mintlactone (VI) and isomintlactone (VII) were prepared from 2‐(1′‐ hydroxy‐4′‐methylcyclohexan‐1′‐yl) propanoic acid (III) which was obtained by reaction of propanoic acid (I) with 4‐methylcyclohexanone (II) using lithium naphthalenide in the presence of diethylamine. Compound (VI) could be separated from compound (VII) by silica gel column chromatography. Several new 2‐(2′‐ hydroxy‐4′‐methyl‐1′‐cyclohexylidene) carboxylic acid lactones which may be used as perfumery materials, were obtained in good yield by this method.
Fluorocarbon microemulsions
Authors: Ceschin C. , Roques J. , Malet‐Martino M. C. , Lattes A.
Published: July 2010

The microemulsification of various perfluorinated (or almost completely fluorinated) oils with different perfluorinated (or almost completely fluorinated) surfactants with or without cosurfactant is described. Ternary or pseudoternary phase diagrams are discussed. The sizes of the monophasic areas are related to surfactant and cosurfactant nature, weight ratio surfactant/cosurfactant and oil.
A microcomputer‐controlled facility for the analysis of phases from the AKUFVE mixer‐centrifuge unit
Authors: Waterman M. J.
Published: July 2010

An AKUFVE mixer‐centrifuge unit is used to collect distribution data for plutonium and uranium in a nitric acid/tributyl phosphate system under various conditions. The equipment necessary to make on‐line measurements in both phases and to perform off‐line titrations of the nitric acid is described. An explanation is given or the design of the Control Program. Written in BASIC with a few machine code subroutines, the program executes blocks of code of ‘sequences’ corresponding to particular functions. There are a dozen sequences which may be called in any order or individually to perform these functions.
The catalytic oxidation of organic air pollutants. Part 3. Catalysts from manganese and copper sulphates
Authors: Heyes Christopher J. , Irwin James G. , Moss Ronald L.
Published: July 2010

Manganese sulphate and copper sulphate were evaluated as the basis of catalysts for the control of organic air pollutants responsible for malodorous process emissions. Tests were made with low concentrations, 100 volumes × 10−6 in air, (i.e. 100 parts × 10−6 by volume), of methyl mercaptan or mercaptan + n‐butanal as a function of temperature and time to determine efficiencies for destructive oxidation. The complex pattern of odorant removal and product formation observed using manganese sulphate is discussed in terms of active sites which convert mercaptan to SO2 but are inhibited by the onset of dimethyl disulphide formation at higher temperatures; reactions between the odorants may also occur. Copper sulphate formed dimethyl disulphide at the lower temperatures but only SO2, SO3, CO and CO2 were detected above 300°C; after a 100 h durability test at 400°C, the odour removal efficiency determined by dynamic dilution olfactometry was 99.9%. Hence copper sulphate is preferable to manganese sulphate and is equal in performance to the copper oxide tested previously (Part 1) but with the advantage of a stable performance from the outset under sulphating conditions.
Adsorption and 13C N.m.r. studies of ethene, ethane and carbon monoxide on zn‐ and cd‐exchanged A‐zeolites
Authors: Emesh Ismail T. A. , Gay Ian D.
Published: July 2010

The adsorption of C2H4, C2H6 and CO has been studied on Zn2+‐exchanged A‐zeolites. Partial exchange with Zn2+ or Cd2+ increases the adsorption capacity for C2H4 and CO. Complete Zn2+ exchange leads to a decrease, indicating a complicated variation of cation positions with exchange level. N.m.r. measurements are consistent with adsorption of C2H4 as weak π‐complexes on the divalent cations. Weak specific adsorption complexes are also demonstrated for CO.
Spontaneous emulsification aspect of enhanced oil recovery
Authors: Egbogah Emmanuel O. , Dawe Richard A.
Published: July 2010

Recent studies have suggested the possibility of spontaneous emulsification as a mechanism for enhanced oil recovery (EOR). The discussions have, however, remained essentially qualitative. A study was therefore undertaken to estimate quantitatively the contribution of spontaneous emulsification as an EOR mechanism. The tests were conducted on several bulk liquid/liquid systems as well as by displacement experiments in unconsolidated synthetic sand packs. Spontaneous emulsification was found to be a mechanism for EOR: the estimated extra contribution to EOR due to this mechanism was found to be significant in laboratory scale displacement experiments. Tertiary recovery was always greater when spontaneous emulsification was evident than otherwise. Results of tests on bulk liquid/liquid systems indicate that the occurrence or absence of spontaneous emulsification can be correlated with the values of ‘partition parameter’. It may be concluded that higher oil recoveries may be achieved in chemical EOR processes where interface mass transfer (and the accompanying spontaneous emulsification) occurs. The evaluation of efficiency of residual oil mobilisation through the capillary number theory (with and without spontaneous emulsification) is also discussed. Displacement tests with spontaneously emulsifying systems showed that residual oil left behind a conventional waterflood was mobilised in a range of capillary numbers much less than that which applies to low‐tension waterfloods.
The concentration of rubidium chloride in carnallite and its preparative separation by ion‐exchange
Authors: Ratner Rachel , Mittelman Judith , Kohn David H.
Published: July 2010

A two‐stage process for the preparative separation of rubidium chloride from carnallite from the Dead‐Sea Works, Israel, is described. In the first stage rubidium chloride is enriched by successive decompositions and recrystallisations of carnallite from an Rb+ content of 0.02% up to about 4%. In the second stage pure rubidium chloride is obtained by means of displacement development chromatography using a polystyrene‐sulphonic acid resin followed by a rubidium‐selective cation exchange resin.
Polymeric additives for pour point depression of residual fuel oils
Authors: Naga Hamdi H. Abou El , Azim Wedad M. Abou El , Ahmed Mohamed M.
Published: July 2010

Esters of styrene‐maleic anhydride copolymers were synthesised by reacting styrene with maleic anhydride and esterifying the product with fatty alcohols. The resulting copolymers were purified and tested as pour point depressants for residual fuel oils. Comparative evaluation of these esters of styrene‐maleic anhydride copolymers with some commercial additives showed their good activity.
A computer study of liquid‐liquid stage‐wise calculations in typical and new countercurrent contacting
Authors: Hughes Michael A. , Parker Nicholas
Published: July 2010

A new scheme for contacting aqueous metal solutions with organic extractants in liquid‐liquid systems is described. The method is shown to give advantages in organic chemical usage under certain conditions. The application to the CuSO4/ H2SO4/LIX64N system is described.
Phase transfer catalysed esterification of phenols with aliphatic acid chlorides
Authors: Direktor D. , Effenberger R.
Published: July 2010

The phase transfer catalysed esterification of phenols with aliphatic acid chlorides was carried out in a basic bi‐phasic aqueous‐organic medium. Unhindered phenols, i.e. having at least one free ortho position, gave good to quantitative yields of ester while ortho disubstituted phenols gave low to moderate yields of ester only with the higher, less water soluble acyl homologues (≧C5). Phenol‐free ester was easily obtained by simple phase separation and evaporation of the organic phase.
Thermal and textural characteristics of modified silica
Authors: Selim Suzy A. , Hanafi Said , Abd‐El‐Khalik Mohamed , Ismail Mohamed
Published: July 2010

A silica gel characterised as predominently microporous, with the remaining pores of limited dimensions which do not permit capillary condensation, is modified with aqueous solutions of acetic acid, glycine and β‐alanine. The modified samples are investigated and compared with a water soaked sample by means of differential thermal analysis, thermogravimetry and i.r. spectroscopy. Textural measurements are also carried out on the parent samples and those produced in the temperature range 110–600°C. Acetic acid is both physically and chemically adsorbed; a surface ester is formed. Both amino acids are physically adsorbed but no chemical interaction has been detected. Glycine and β‐alanine decompose differently when adsorbed on to the silica surface than when in the pure state. The specific surface area decreases upon modification, reaching half the value of the pure silica for the β‐alanine modified sample. Pore structure analysis, shows that the microporous nature of the modified samples decreases in the modifier order acetic acid < glycine < β‐alanine. The adsorbed β‐alanine molecules block most of the micropores present.
The influence of apex diameter on the pattern of solid/liquid ratio distribution within a hydrocyclone
Authors: Ahmed A. A. , Ibraheim G. A. , Doheim M. A.
Published: July 2010

Knowledge of the pattern of solid/liquid ratio distribution within a hydrocyclone is very important for reliable design and efficient operation. This pattern was examined using a 100mm hydrocyclone for a wide range of apex diameters at high solid contents of the feed pulp. The measurements were taken along orbit radii at several horizontal level positions along the cyclone length. The results give a complete pattern of pulp‐solid content distribution for the studied parameters. An empirical equation relating the pulp solid/liquid ratio with all the studied variables was established. The predicted data show good agreement with the experimental results.
The influence of physico‐chemical and operating parameters on the filtration of the precipitate of hydrated Zr(IV) oxide
Authors: Kawalec‐Pietrenko Boz̊enna , Ruszel‐Lichodzijewska Barbara
Published: July 2010

An experimental investigation of the filtration of the colloidal precipitate of hydrated Zr(IV) oxide is presented. The influence of pH over the range from 3 to 12, of the ageing time of the suspension and of the procedure for the precipitation of hydrated Zr(IV) oxide on the course of its filtration under the constant pressure was studied.
A continuous process for dye removal from liquid effluents using carbonised wool waste
Authors: Malmary Guy , Périneau Francis , Molinier Jaques , Gaset Antoine
Published: July 2010

Industrial dyeworks are often conspicuous due to discoloration of rivers and streams into which they discharge waste materials. The adsorption process put forward for the treatment of such effluent makes use of wool‐carbonising waste made up of carbonised keratinic fibres and a hydrolysed vegetable material rich in ionic groups. This agro‐industrial by‐product showed a remarkable capacity for fixing surfactants, metallic cations and dyes. The current pilot project studied the removal of Maxilon Red from aqueous solutions by adsorption of the dye into the vegetable part of waste from the carbonising process. The operation was carried out continuously in a series of mixers. An examination of the hydrodynamic behaviour of a particular type of extractor established operating conditions favouring efficient removal of dyes from the effluent. A maximum dye removal rate of around 98% was possible.
Alkylation of phenol with isobutene catalysed by cation exchange resin: A kinetic study
Authors: Unni P. N. , Bhatia S.
Published: July 2010

Alkylation of phenol with isobutene catalysed by Amberlyst 15 (cation exchange resin) was carried out in a batch reactor in the liquid phase. The reaction rate increased with increase in catalyst concentration and reaction temperature. Resin particle size and stirrer speed had virtually no effect on the rate under the experimental conditions. The rate data were correlated with a kinetic model based on homogeneous reaction. The apparent activation energies were found to be 57.7, 51.5 and 46.4 kJ mol‐1 for the formations of o‐alkylate, p‐alkylate and dialkylate respectively. The resin was found to have higher selectivity than the sulphuric acid catalyst.
Synthesis of some new thiophene derivatives with antimicrobial activity. part I
Authors: El‐Maghraby Ahmed A. , Mohamed Nour A.
Published: July 2010

For possible antimicrobial activity, thiophene‐2‐sulphonyl chloride was condensed with primary or secondary amines, phenols and hydrazine hydrate. Thiopene‐2‐sulphonhydrazones and thiophene‐2‐sulphoniminoazo derivatives were obtained. The constitution of some of the prepared products is discussed in the light of their infrared spectra. The biological activities of all prepared compounds were tested.
A convenient preparative method for carboxylic acids containing the dichlorocyclopropane ring system
Authors: Sugahara Kotoji , Fujita Tsutomu , Watanabe Shoji , Suga Kyoichi
Published: July 2010

Various carboxylic acids containing the dichlorocyclopropane ring system were prepared from the direct reaction of unsaturated carboxylic acids with dichlorocarbene. For example, 2‐(2,2.dichloro‐1‐methylcyclopropyl)‐ethanoic acid (II) was prepared from 3‐methyl‐3‐butenoic acid (I), 50% aqueous sodium hydroxide solution and benzyltriethylammonium chloride (BTEAC) in 80% yield. Similarly, 3‐(2,2‐dichloro‐3,3‐dimethyIcyclopropyl)‐2,2‐diethyl propanoic acid (IV) was obtained in 80% yield from 2,2‐diethyl‐5‐methyl‐4‐hexenoic acid (III). The dichlorocyclopropane compounds, (II) and (IV), are potent insecticides against houseflies (Takatsuki strain in Japan).
Modifications to a commercial flow microcalorimeter system
Authors: Tasker Ian R. , Wood Robert H. , Albert Henry J.
Published: July 2010

Commercially available calorimetry systems now account for the major portion of thermochemical research. A number of simple modifications to one such calorimeter have been found to maintain the accuracy and precision of the data obtained while achieving increased efficiency and reduced cost.
Recovery of chromium from waste electroplating liquors by ion‐exchange on casein. part 1. pilot plant studies
Authors: Davey Peter T. , Houchin Martin R. , Winter George
Published: July 2010

The ion‐exchange properties of cross‐linked caesin were used to selectively recover Cr(VI) from waste electroplating solutions. Acidic solutions containing Cr(VI), Cr3+, Zn2+ and Cd2+ were passed through an ion exchange column containing 35 kg of + 60 mesh casein. The casein had been previously cross‐linked using a 2% w/w formaldehyde solution. The anionic Cr(VI) was adsorbed by the casein while the cationic Cr(III), Zn(II) and Cd(II) passed through the column. Cr(VI) was eluted with ammonia. The casein was then washed, regenerated with sulphuric acid and the cycle repeated. The eluant for each cycle consisted of the (NH4)2 CrO4 eluate from the preceeding cycle with added ammonia.
The adsorption of dyestuffs from aqueous solutions using activated carbon. iii. intraparticle diffusion processes
Authors: Mckay Gordon
Published: July 2010

The rate of dye removal from aqueous solution has been found to vary linearly with the square root of time for much of the adsorption period. A rate parameter, k, has been defined to explain intraparticle diffusion on a quantitative basis. This rate parameter has been correlated against the process variables thus providing useful design data.
Discrimination of rival kinetic models in heterogeneous catalysis by the dynamic behaviour of products
Authors: Kobayashi Masayoshi , Maeda Yasuo , Takahashi Nobuo
Published: July 2010

The transient response method has been applied to discriminate between rival kinetic models derived from the conventional Hougen‐Watson procedure in heterogeneous catalysis, by using some old data for the NO‐CO reaction, dehydrogenation of sec‐butanol, hydrogenation of phenol, and dehydrogenation of tert‐butanol. A computer technique is commonly used for the simulation of the transient response curves of products caused by the concentration jump of reactants in a flow type reactor. The shapes of the calculated response curves are of various characteristic types (depending on the given model) which allow for easy discrimination between rival kinetic models. The difficulty of the discrimination in some particular models is also discussed.
Medium effect on the reaction of gibb's reagent with sodium thiosulphate
Authors: Harfoush A. A.
Published: July 2010

Rates of the reaction between Gibb's reagent and sodium thiosulphate have been measured in water‐glycerol mixtures over the temperature range 25–40°C. Log(k) varies linearly with the reciprocal of the dielectric constant. The energy of activation and the thermodynamic parameters of activation are calculated and discussed in terms of solvent properties.
Electrochemical reduction of some 5‐substituted‐4‐thiohydantoins at the dme
Authors: Aboutabl M. A. , Fahmy H. M. , Abdel Aziz M. A. , Abdel Rahman H.
Published: July 2010

The polarographic behaviour of a series of 5‐arylidene‐4‐thiohydantoin derivatives is reported and discussed. The reduction proceeds via a CECE mechanism in acid media with the formation of a 5‐benzyl‐4‐thiohydantoin and other products. The mechanism is confirmed through pKa determinations and Hammett's σ‐E1/2 relations.
High‐purity mercuric iodide
Authors: Nicolau Y. F.
Published: July 2010

Two methods of obtaining high purity HgI2 by wet‐synthesis are described: one by direct synthesis from the elements and the other by a double exchange reaction. Further purification of the synthesised HgI2 by recrystallisation, electrolysis and sublimation is described. The efficiency of the purification methods is tested by emission spectroscopy and by mass spectrometry analyses.
A procedure for quantitative 13c‐n.m.r. application to the characterisation of the naphtha fraction of petroleum crude
Authors: Srivastava Shanti P. , Bhatnagar Ajay K. , Joshi Girish C.
Published: July 2010

A method for optimising the conditions for the quantitative 13C‐n.m.r. measurement is suggested and has been applied to the compositional studies of naphtha fractions (50–100°C and 100–150°C) of Darius crude oil. The novelty of the method is that we can pre‐estimate the pulse repetition time for unknown samples. It has been shown that the various compositional parameters thus obtained are in satisfactory agreement with those obtained from the elemental analysis, fluorescent indicator adsorption (FIA) and 1H‐n.m.r. spectrometry.
Retention of some non‐mercurial fungicides in paint films
Authors: Hughes Clifford A. , Taylor Colin G. , Thamaung Anek
Published: July 2010

The fungicides, 3,5‐dimethyltetrahydro‐1,3,5‐thiadiazine‐2‐thione (DTTT) and 4‐tolyldiiodomethylsulphone (TDMS) have been prepared labelled with 14C and incorporated into polyvinylacetate emulsion (PVA), styrene/acrylic emulsion (acrylic) or alkyd gloss (alkyd) paints. Test plates prepared from these paints have been exposed in both tropical and temperate conditions and losses of fungicides have been followed radiometrically. In outdoor conditions, DTTT is rapidly lost from all the paints. Indoors, DTTT is retained well (50% after 150 days) only by alkyd paint. TDMS is well retained in indoor conditions by all the paints. Outdoors however, retention in PVA and acrylic films is less than 50% after 150 days and is poorer in tropical conditions. About 90% of the TDMS is retained in alkyd films for an indefinite period in temperate conditions: in tropical conditions, 80% is retained after 150 days. Comparisons of losses from paint films of mercurial and non‐mercurial fungicides show that TDMS is a satisfactory substitute for the more commonly used mercurials.
Reduction of nitric oxide with ammonia on silica‐supported vanadium oxide catalysts
Authors: Shikada Tsutomu , Fujimoto Kaoru , Kunugi Taiseki , Tominaga Hiro‐O
Published: July 2010

Highly active catalysts for the reduction of nitric oxide with ammonia can be obtained by supporting vanadium oxide, more than 15% by weight, on a silica gel with micropores of a mean diameter larger than 10 nm, followed by calcining it in the temperature range from 250 to 350°C. Both pre‐impregnation with a small amount of titania and addition of ammonium bromide increased the activity markedly. The catalyst gave an NO conversion level of 100% at 150°C. A series of life tests of the catalysts, which was performed at 230°C using a simulated flue gas containing 700 parts/106 of sulphur dioxide, demonstrated that their activities were stable for more than 300 h. Little irreversible change in the catalyst properties was observed after the test.
Denaturing of single electrospun fibrinogen fibers studied by deep ultraviolet fluorescence microscopy
Authors: Kim Jeongyong , Song Hugeun , Park Inho , Carlisle Christine R. , Bonin Keith , Guthold Martin
Published: July 2010

Deep ultraviolet (DUV) microscopy is a fluorescence microscopy technique to image unlabeled proteins via the native fluorescence of some of their amino acids. We constructed a DUV fluorescence microscope, capable of 280 nm wavelength excitation by modifying an inverted optical microscope. Moreover, we integrated a nanomanipulator‐controlled micropipette into this instrument for precise delivery of picoliter amounts of fluid to selected regions of the sample. In proof‐of‐principle experiments, we used this instrument to study, in situ, the effect of a denaturing agent on the autofluorescence intensity of single, unlabeled, electrospun fibrinogen nanofibers. Autofluorescence emission from the nanofibers was excited at 280 nm and detected at ∼350 nm. A denaturant solution was discretely applied to small, select sections of the nanofibers and a clear local reduction in autofluorescence intensity was observed. This reduction is attributed to the dissolution of the fibers and the unfolding of proteins in the fibers. Microsc. Res. Tech., 2010. © 2010 Wiley‐Liss, Inc.
Homology of prostomial and pharyngeal structures in eunicida (Annelida) based on innervation and morphological similarities
Authors: Zanol Joana
Published: July 2010

Eunicidan bristle worm families are commonly identified by the shape of their prostomia and pharyngeal structures. However, current hypotheses of homology among these structures are conflicting, making it difficult to assess morphological evolution, reconstruct phylogeny, and produce a stable classification. To generate more consistent hypotheses of homology among eunicidan anterior structures, the author examined the anterior morphology and the nervous system stained with anti‐α‐tubulin and serotonin antibodies in representative species of Eunicidae, Onuphidae, Oenonidae, Dorvilleidae and Lumbrineridae. The shape of the brain varied conspicuously among families; however, it has mostly the same commissures (usually two of the dorsal and five of the ventral roots of the circumoesophageal connective). The stomatogastric system is also conservative in composition, having two main pairs of stomatogastric nerves which vary in their relative position among the different families. Innervation similarities combined with correspondence and topological morphological similarities made it possible to present explicit hypotheses of primary homology of features, such as buccal lips, pharyngeal fold, and dorsolateral fold anterior extension. Buccal lips are present in all families; however, ventral pads on the prostomium of the Dorvillea line of Dorvilleidae are anterior prolongations of the pharyngeal fold and not buccal lips. All examined taxa, except dorvilleid species, have conspicuous dorsolateral fold anterior extension. In Eunicidae, this anterior extension is a transverse band, while in other families it is a pair of folds. Observed similarities also gave insights on the homology of maxillary elements of Dorvilleidae, providing background knowledge for future studies. J. Morphol., 2010. © 2010 Wiley‐Liss, Inc.
Simulation of quantum transport in double‐gate MOSFETs using the non‐equilibrium Green's function formalism in real‐space: A comparison of four methods
Authors: Sabry Yasser M. , Abdolkader Tarek M. , Farouk Wael F.
Published: July 2010

Quantum effects play an important role in determining the double‐gate (DG) MOSFETs characteristics. The non‐equilibrium Green's function formalism (NEGF) in real‐space (RS) representation provides a rigorous description of quantum transport in nanoscale devices. Unfortunately, the traditional NEGF framework has the disadvantage of being heavy in computations. Methods that reduce the computations exist in the literature like the recursive Green's Function (RGF) algorithm, the contact block reduction (CBR) method, and Gauss elimination (GE) method. Comparison of the simulation time of the traditional NEGF, the RGF algorithm, the CBR method, and the GE method was always theoretical and based on approximate estimates. In this work, we carry out a real comparison between the four methods by implementing them inside the same simulator, using them to simulate the same device dimensions and parameters on the same machine. It is demonstrated that the RGF algorithm or the GE method introduce about one order of magnitude reduction in simulation time below that traditional NEGF, whereas the CBR method yields the smallest simulation time with about two orders of magnitude reduction. Copyright © 2010 John Wiley & Sons, Ltd.