bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of sulphonated by‐products of dodecyl benzene production
Authors: Abou el Naga Hamdi Hassan , Wedad Abdel Azim M. , Naguib Sidaros K.
Published: July 2010

Light and heavy alkylated benzene accumulated as by‐products during dodecyl benzene production were studied. The chemical structures of these by‐products were established via various spectroscopy and chromatography techniques. Results showed their suitability for sulphonation and formulation of liquid surfactants.

The light by‐product, with its high eicosyl benzene content and likely orthosulphonation, was used satisfactorily to formulate wetting agents and emulsifiers. On the other hand, the heavy alkylated benzene was found to contain a high percentage of C12‐C18 branched side chains. Surfactants formulated from it gave high detergency power and can be recommended for heavy duty applications.
Characterization of hydrous titania from titanous chloride—I. Thermal studies
Authors: Ragai Jehane
Published: July 2010

The thermal properties of a number of titania gels prepared from titanous chloride under various conditions of pH and oxidizing agents, have been studied by simultaneous thermogravimetry, differential thermal analysis and differential thermogravimetry. The results obtained suggest that ligands incorporated in the precipitated gels play a crucial role as far as establishing the dehydration characteristics of these gels. Ageing in water leads, in most cases, to the elimination of coordinatively bound water and to a marked decrease in the final weight loss. In the case of hydrogen peroxide oxidized samples, free radicals incorporated in the inner coordination sphere of titanium control, in most cases, the low temperature behavior.
Kinetic study of sensitized norbornadiene photoisomerization
Authors: Vicente Manuel , Esplugas Santiago
Published: July 2010

One of the best systems for photochemical storage of solar energy is the interconversion between norbornadiene and quadricyclane. This paper presents a kinetic study of norbornadiene photoisomerization sensitized with acetophenone, using ethanol as solvent. This photoreaction was carried out at 25°C and at high reaction conversion yield, quadricyclane being detected as the only reaction product. As a result of that, the global isomerization quantum yield is a norbornadiene and quadricyclane concentration function. In the same way, the influences of temperature and solvent on the photoisomerization kinetics have been studied.
Factors affecting the enzymic susceptibility of alkali and acid pretreated sugar‐cane bagasse
Authors: Fox David J. , Gray Peter P. , Dunn Noel W. , Marsden Warwick L.
Published: July 2010

Acid and alkali pretreatments were studied to identify those factors which are critical in determining the susceptibility of a lignocellulosic substrate (bagasse) to enzymic hydrolysis. The different effects of each treatment on the structure of the bagasse affected the subsequent susceptibility to enzymic attack in different ways. The acid treatments appeared to act by disrupting the lignin structure, probably by hydrolysing the carbohydrate chains attached to the lignin, as well as the lignin itself. The attack on the carbohydrate content removed outlying material in the cell wall (i.e. hemicellulose and amorphous cellulose) to expose a ‘core’ of more resistant regions. The alkali treatments appeared to produce a more open structure by penetrating the inner layers and selectively removing hemicellulose molecules as well as breaking some lignin—carbohydrate bonds. The different treatments resulted in structural changes which were found to affect the hydrolysis mechanism.
Accumulation of uranium by biopigments
Authors: Sakaguchi Takashi , Nakajima Akira
Published: July 2010

The uranium adsorbing abilities of various biopigments were investigated. Extremely high adsorption capacities for uranium were found in melanin and bioflavonols (quercetin and morin) having chelating positions with uranium. As a step towards improving the adsorption characteristics of the bioflavonols, quercetin and morin were immobilized on both Bemberg rayon fiber and polyaminostyrene, and the basic features of uranium adsorption by the immobilized bioflavonols were studied. The bioflavonols immobilized on Bemberg rayon fiber have a highly selective capacity adsorb uranium. Uranium recovery from seawater by the immobilized bioflavonols was markedly affected by the pH value of the seawater, and the uptake at pH 8, which is the pH value of natural seawater, was difficult. However, this adsorbent can accumulate large amounts of uranium from non‐saline water. Thus it can be used to remove and recover uranium from uranium refining waste water and other waste sources.
Characterization of hydrous titania from titanous chloride—II. Infrared studies
Authors: Ragai Jehane
Published: July 2010

Infrared studies were carried out on a number of titania gels prepared from titanous chloride under various conditions of pH and oxidizing agents. Oxygen oxidized gels display, below 1200 cm−1, two bands at 1080 cm−1 and 970 cm−1 which are related to the formation of hydroxo complexes of titanium. Heat treatment at 110°C and ageing in water led to successive small shifts of these bands towards higher energies. In the case of hydrogen peroxide oxidized samples, prepared at a low pH, two significant bands appear at 1045 cm−1 and 1389 cm−1 and are attributed to O−2 and HO2 free radicals, respectively. The same kind of gels prepared under neutral or alkaline conditions are shown to incorporate hydroxo complexes of titanium; however, ageing in water leads to the reappearance in these gels of the 1045 cm−1 band attributable to O−2 free radicals. All gels exhibit two sharp bands at around 1400 cm−1 and 1630 cm−1, characteristic of NH+4 ions and molecular water, respectively.
The surface excess and the rate of copper extraction by hydroxyoximes
Authors: Szymanowski Jan , Prochaska Krystyna
Published: July 2010

The interfacial tension is determined for some model 2‐hydroxy‐5‐alkylbenzophenone E‐oximes, and the surface excess is calculated according to the different adsorption isotherms. The relationship between the rate of copper extraction and the surface excess is discussed. It is shown that, depending upon the adsorption isotherm used to calculate the surface excess, different relations both between the extraction rate and the surface excess and between the surface excess and the oxime concentration are obtained. The interfacial activity of hydroxyoximes is only a qualitative parameter suggesting the interfacial mechanism for copper extraction, and it cannot give strong evidence quantitatively supporting this mechanism. The predicted reaction orders against oxime demonstrate that the reaction between the oxime molecules from the sublayer and the absorbed intermediate complex is probably the limiting step.
Use of a novel turbidimeter to monitor microbial growth and control glucose concentration
Authors: Yamashita Sunao , Matsunaga Kazuhiko , Miura Hiroshi , Morikawa Makoto , Shimizu Kazuyuki , Matsubara Masakazu , Kobayashi Takeshi
Published: July 2010

A turbidimeter (suspended solid concentration analyser: SSCA) which can measure directly the turbidity of culture broth has been developed. The SSCA was used to monitor baker's yeast and Escherichia coli fermentations. Although the medium conditions changed during the fermentations, the optical densities evaluated from the measurement of SSCA and predetermined calibration curves coincided well with those determined spectrophotometrically. Since SSCA can monitor microbial growth, it was applied to the control of glucose concentration in fed‐batch baker's yeast cultures by assuming a constant growth yield. Glucose concentration in the medium could be maintained between 0.2 and 0.3 g dm−3, and ethanol concentration was less than 4 g dm−3.
Kinetics of untreated orange peel utilisation by fusarium avenaceum
Authors: Moresi Mauro , Clementi Francesca , Rossi Jone
Published: July 2010

The growth behaviour of Fusarium avenaceum in slurry fermentation systems using untreated orange peel as substrate was studied in order to assess the eventual effect of impeller speed on mechanical disruption of mycelial hyphae. By applying the elementary balance method in combination with a Monod‐type kinetic equation, it was possible to formulate not only an unstructured model, but also the stoichiometry for such a mycelial fermentation process. In particular, the main yield coefficients, as well as the kinetic parameters, appeared to be independent of the impeller speed, at least within the experimental range of 450–900 min−1 (equivalent to peripheral impeller speeds of 3.8–7.5 m s−1). Moreover, as far as the kinetic parameters are concerned, it was impossible to discriminate the contribution of μM and Ks on the overall mycelial kinetics at the orange peel concentration studied. The rate of fungal formation was found to be first order in the concentration of the limiting substrate, probably because the concentrations of the organic carbon compounds utilisable by F. avenaceum were smaller than Ks.
Kinetics of homogeneous catalytic chlorination of acetic acid
Authors: Martikainen Päivi , Salmi Tapio , Paatero Erkki , Hummelstedt Leif , Klein Paul , Damén Henrik , Lindroos Torsten
Published: July 2010

The kinetics of the chlorination of acetic acid (HAc) to monochloroacetic acid (MCA) and the physical solubility of chlorine in HAc and its mixtures with MCA were investigated in a laboratory scale semibatch reactor. The temperature dependence of the Henry's constant was determined from solubility data obtained at temperatures between 70°C and 110°C. The kinetic experiments were performed at 75–100°C with 3–13 mol % acetyl chloride (AcCl) and 0–5 weight % H2SO4added as catalysts. Gas chromatography was used to determine the concentrations of HAc, MCA, dichloroacetic acid and AcCl during the experiments. The results indicate that the reaction rate is independent of the concentrations of HAc and Cl2whereas the reaction is significantly enhanced by MCA and H2SO4. The effects are explained by a reaction mechanism involving the acid catalyzed enolization of AcCl as the rate‐determining step. A rate equation based on this mechanism was derived. Kinetic constants included in the equation were determined by regression analysis.
Textural study of a coal from villanueva de rio y minas (sevilla, spain) and of samples prepared from it by acid and heat treatments
Authors: Calahorro Cristobal Valenzuela , Gonzalez Carmen Fernandez , Garcia Alvaro Bernalte , Serrano Vicente Gomez
Published: July 2010

A coal with high inorganic matter content from the mine of Villanueva de Rio y Minas (Sevilla, Spain) (VRMO) was classified by following the ASTM norms as a high volatile matter A bituminous coal. The starting coal was treated either with HCl (VRMH) or thermally at 1000°C for 2 h (VRMOC), the resultant yield values (referred to as VRMO, dry) being, respectively, 97 and 79%; also VRMH was either treated with HNO3 (VRMN) or HF (VRMF), and the yield values (referred to as VRMH, dry) of the process were then 95 and 59%. The textural characterization of samples was effected by adsorption of CO2 at 273 K and of N2 at 77 K, as well as by mercury porosimetry. VRMN presents the highest value of the apparent surface area (SD‐R=219 m2 g−1) (CO2, 273 K) and of the specific surface area of mesopores and macropores (Sme+ma=5.2 m2 g−1) (N2, 77 K), while the greatest value of the cumulative specific surface area of macropores (Sma=1.2 m2 g−1) (mercury porosimetry) corresponds to VRMOC; S values are expressed on a per gram of original sample basis. The micropore volume accessible to CO2 at 273 K increases in both the HCl and the HNO3 treatment and decreases in the HF and heat treatments. The HCl and HNO3 treatments produce an increase of the mesoporosity; the HF treatment seems to affect in a special way the mesoporous texture. Furthermore, the heat treatment gives rise to a notable development of the macroporosity.
Some remarks about the estimation of the solubility parameter of low volatile compounds from gc data
Authors: Bermejo Jenaro , Guillén Maria D.
Published: July 2010

Approximate solubility parameters of monomeric stationary phases can be calculated from gas chromatographic retention volumes of aliphatic saturated hydrocarbons; and some other properties, such as the molar volume and the latent heat of vaporization, by applying the regular solution model to the chromatographic process. By including data of aromatic hydrocarbons, solubility parameters of aromatic stationary phases, nearer to the experimental ones, can be obtained. The inclusion of data of olefines, however, is irrelevant. The method can be applied to low volatile compounds usable as the stationary phase in gas chromatography (GC) of hydrocarbons.
Phase transfer catalysed esterification of phenols with aliphatic acid chlorides. Part II: Phenyl acrylates from 3‐chloropropionyl chloride
Authors: Direktor David , Effenberger Reinhard
Published: July 2010

The phase transfer catalysed reaction of phenols with 3‐chloropropionyl chloride was carried out in a basic bi‐phasic aqueous—organic medium. Phenyl acrylates were isolated in good yields with high (>99%) purity.
Synthesis by enzymatic catalysis. IV. Transesterification of n‐acetyl‐L‐tyrosine ethyl ester with α‐chymotrypsin in water—hexanol—aot micelles
Authors: Testet Eric , Baboulene Michel , Speziale Vincent , Lattes Armand
Published: July 2010

A new type of microemulsion system (Aerosol‐OT, water, hexanol) was used to entrap an enzyme (α‐chymotrypsin) in a reverse micelle. N‐acetyl L‐tyrosine ethyl ester can be solubilised in this medium to give N‐acetyl L‐tyrosine hexyl ester in a good yield (80%). This is the first report of a successful enzymatic transesterification in a micellar medium.
The treatment of anaerobically digested palm oil mill effluent by pressurised activated sludge
Authors: Ho C. C. , Tan Y. K.
Published: July 2010

The application of the pressurised activated sludge process in the secondary treatment of anaerobically digested liquor of palm oil mill effluent (POME) as influent under various physical conditions was studied. Separation of the particulates was by way of a dissolved air flotation unit. Results showed that a high efficiency in pollutant removals could be achieved and the final treated water was of good effluent quality. The high efficiency of the process was linked to the high rate of oxygen transfer at elevated pressure in the reactor. With a dissolved oxygen level of 10–14 mg dm−3 in the reactor, filamentous growth and sludge bulking were prevented. The kinetic coefficients for the process were also evaluated. It is envisaged the process could complement the anaerobic digestion in a two‐stage complete treatment system for POME.
Study of subbituminous coal chars: Effect of heat treatment temperature on their structural characteristics
Authors: Gutierrez Maria Del Carmen , Cukierman Ana Lea , Lemcoff Norberto O.
Published: July 2010

Changes in the apparent surface area that are produced by carbonisation of a subbituminous coal at different temperatures are followed by adsorption of CO2 at 273 K and 298 K, the Dubinin—Radushkevich equation being used. Activated diffusion effects are found for the char samples prepared at 973 and 1173 K. A maximum in the apparent surface area is found at 1073 K.
The conversion of polysaccharides to hydrogen gas. Part II: The catalytic decomposition of formaldehyde in the aqueous phase
Authors: Hill S. P. , Winterbottom J. M.
Published: July 2010

The aqueous phase decomposition of formaldehyde, to hydrogen gas, catalysed by platinum—copper chromite, has been carried out in the temperature range 20–60°C, at a solution pH of 12.

The production of hydrogen was favoured by intermediate temperatures (40–50°C) and an activation energy of 22.2 kJ mol−1 (5.3 kcal mol−1) was recorded. The rate of reaction was first order with respect to OH− ion concentration at low alkali concentrations and was first order with respect to HCHO concentration at all concentrations. At high alkali concentrations the reaction should become zero order with respect to OH− ion concentration, but initial rates actually decrease under these conditions having passed through a maximum. The rate of reaction was directly proportional to catalyst weight at low catalyst loading, but the relationship became non‐linear at high catalyst loadings. Conversions of formaldehyde to hydrogen gas were substantially less than theoretical.

The decomposition reaction has to compete with a number of side reactions such as polymerization of formaldehyde at low temperatures (<40°C) and at higher temperatures with the Cannizzano reaction, aldol condensation, and possibly formaldehyde hydrogenation to methanol. In addition hydrogen loss may occur due to copper chromite reduction. A reaction mechanism is proposed involving a surface formate intermediate.
Drop formation in non‐newtonian liquids under pulsed conditions
Authors: Yaparpalvi Ravindra , Das Tarun R. , Mukherjee Ashok K.
Published: July 2010

Drop formation from single nozzles under pulsed flow conditions in non‐Newtonian fluids following the power law model has been studied. An existing model has been modified to explain the experimental data. The flow conditions employed correspond to the mixer—settler type of operation in pulsed sieve‐plate extraction columns. The modified model predicts the drop sizes satisfactorily. It has been found that consideration of non‐Newtonian behaviour is important at low pulse intensities and its significance decreases with increasing intensity of pulsation. Further, the proposed model for single orifices has been tested to predict the sizes of drops formed from a sieve‐plate distributor having four holes, and has been found to predict the sizes fairly well in the absence of coalescence.
The effect of temperature on the flow field in a continuous rotating annular electrophoresis column
Authors: Carmichael Gregory R. , Zingher Harry L. , Datta Ravindra , Yoshisato Randall A.
Published: July 2010

The effect of a non‐uniform temperature profile on the flow field in a continuous rotating annular electrophoresis column is investigated. The momentum balance equation is solved for packed as well as unpacked columns using a centered‐difference finite difference technique with a known temperature profile. The packed column analysis utilizes a parallel annular channel model similar to the capillary channel model used in packed bed columns. Results indicate that the changes in density and viscosity as result of the temperature variation have a significant effect on the flow field. Effects of voltage gradient and column geometry are also discussed.
Colloid stabilization by polyelectrolytes. Application to decontamination processes of nuclear reactors
Authors: Baumgartner Erwin , Torok John
Published: July 2010

The redeposition of colloidal magnetite particles can reduce the effectiveness of the chemical decontamination of nuclear reactors. Sodium salts of the following anionic polyelectrolytes were evaluated as particle stabilizers: polyacrylic acid, polymethacrylic acid, poly (methyl vinyl ether/maleic anhydride), sulfonated polymers. A cationic polyelectrolyte, a polyamine, was also evaluated. An active and an inactive oxidized carbon steel sample were treated in the same experimental set‐up with the decontaminating reagent and with or without the polyelectrolyte. Activity pick‐up by the inactive sample was measured. When no polyelectrolyte was added, 15% of the Co‐60 activity was redeposited. With polyelectrolyte addition in the 5–450 mg kg−1 range, the Co‐60 activity redeposition ranged from 8.5 down to 0.8%. Polyacrylic acid was the most effective reagent. The transfer of the magnetite outer oxide crystals from the active to the inactive surfaces was identified on SEM micrographs.
Removal of copper and cadmium from hydrometallurgical leach solutions by fluidised bed electrolysis
Authors: Boyanov Boian S. , Donaldson John D. , Grimes Susan M.
Published: July 2010

A fluidised bed cell which consists of a bed of inert glass beads, in which are immersed expanded mesh electrodes, is used to provide high ion transfer conditions making it possible to recover metals efficiently from dilute solutions. The use of the cell in the removal of Cu and Cd from dilute solutions is described, and the effects of cathode density, pH, time, type of electrode, distance between the electrodes and presence of other ions in solutions studied. These investigations are then extended to examine the electrolysis of solutions obtained by leaching a copper—zinc calcine.
Rate and mechanism of divalent metal transport through supported liquid membrane containing di(2‐ethylhexyl) phosphoric acid as a mobile carrier
Authors: Huang Ting‐Chia , Juang Ruey‐Shin
Published: July 2010

The rate and mechanism of copper, cobalt, nickel and zinc transport through a supported liquid membrane containing di(2‐ethylhexyl) phosphoric acid as a mobile carrier were studied, respectively. The permeation rate equations have been derived taking into account aqueous film diffusion, interfacial chemical reaction and membrane diffusion as simultaneous controlling steps. The possible rate‐controlling steps were estimated by comparing the relative values of the three successive resistances. The measured permeation rates of zinc agreed well with the proposed mechanism in this study.
Mycelial and extracellular inulinases from Fusarium oxysporum grown on aqueous extract of Cichorium intybus roots
Authors: Gupta Anil K. , Nagpal Bela , Kaur Narinder , Singh Rangil
Published: July 2010

Mycelial as well as extracellular inulinase (2,1‐β‐D‐fructan fructanohydrolase, ED 3.2.1.7) were produced by Fusarium oxysporum grown on the aqueous extract of Cichorium intybus roots. At 12 days growth of fungus, 86% of this enzyme activity was observed in the medium. The enzymes were partly purified by Sephadex G‐100 column chromatography. The optimum pH and temperature for mycelial and extracellular inulinases were 5.8 and 6.2; and 30°C and 37°C, respectively. The energy of activation for extracellular inulinase was 40.1 kJ mol−1. The molecular weight of both inulinases was about 300 000. High concentrations of inulin did not protect the activity of inulinase against rising temperature. The enzymes did not release oligomers or sucrose from inulin, indicating that they are primarily exo‐acting. The inulinases hydrolysed sucrose and raffinose, but had no effect on melezitose and maltose. Compared with inulinases from other sources, the extracellular and mycelial inulinases have very low Km (Michaelis–Menten constant) values (16.7 and 20 μmol dm−3, respectively) for inulin.
Microscopic observation of Sudan Black B staining to monitor lipid production by microbes
Authors: Thakur M. S. , Prapulla S. G. , Karanth N. G.
Published: July 2010

In experimental investigations on the improvement of yields and productivities of lipids from oleaginous micro‐organisms in fermenters, a bottleneck is the speedy determination of the extent of accumulation of the intracellular lipids. The use of Sudan Black B for staining and direct observation under the microscope enables the rapid observation of the qualitative status of lipid production in the cells. A change in the colour of the stain from dark to light blue observed during the course of the fermentation has been found to be related to a change in the extent of unsaturation of the lipids.
Leaching of MnO2 with mixed non‐aqueous solvent dimethyl sulfoxide–sulfur dioxide
Authors: Raisoni Prafulla R. , Dixit Sharad G.
Published: July 2010

Electrolytic manganese dioxide is dissolved in the mixed non‐aqueous solvent dimethyl sulfoxide–sulfur dioxide (DMSO–SO2) to form manganese disulfate as a final product. Sulfur dioxide does not change the oxidation state of the metal cations in DMSO–SO2 solvent. However, oxidation of sulfur(IV) to sulfur(VI) is possible. The complete MnO2 dissolution occurs in 50 min at a stirring speed of 650 rpm, pH 1, 0.2% solids concentration, 35 × 44 mesh particle size, and 36°C. IR and FTIR evidence has been presented in favor of the formation of SO, S2O, (CH3)2S+ as intermediate species for the proposed mechanism. In the mixed non‐aqueous solvent system the kinetics of leaching is controlled by a mass transport process. The equation 1–⅔α–(1–α)2/3 = kt fits the experimental data very well. This is further supported by scanning electron micrographs, which show a product layer formation on the surface of the MnO2 particle, and by the dependence of k on 1/r.
High activity copper catalyst for one‐step conversion of methanol to methyl formate at low temperature
Authors: Rao V. Madhusudhan , Shankar V.
Published: July 2010

Dehydrogenation of methanol on copper catalysts supported on SiO2 and modified by Cr2O3 was studied in the temperature range of 200 to 270°C. The chief product of reaction was methyl formate together with carbon monoxide and traces of formaldehyde.

It was found that very high and sustained activity could be achieved by the method adopted for preparation of the catalysts. The unused catalyst was completely amorphous, but in catalyst samples used for long periods of time the presence of crystallites in the size range 50 to 65 Å was observed.

Nearly 80% of theoretically obtainable conversion of methanol to methyl formate was achieved in laboratory scale tubular reactor. A catalyst containing Cu:Cr2O3:SiO2 = 5.0:5.90:7.0 prepared by the method described proved to be very active at low temperatures, giving 41% conversion to methyl formate at 230°C for long periods of use. No interaction between the active component and the support was noticeable.

Addition of chromia improved the catalyst texture and stability. When nickel was present in quantities less than 1.25%, it acted as a promoter and gave improved performance.
Prediction of kLa in conventional stirred fermenters
Authors: Moresi Mauro , Patete Michele
Published: July 2010

In this work values of the volumetric oxygen transfer coefficients (kLa) were determined (by means of the sulphite oxidation technique) in a series of 8‐ to 1000‐dm3 stirred fermenters over a wide range of superficial air velocities and impeller rotational speeds. In spite of the great scale‐up ratios, very different operating conditions and geometric dissimilarity, it was possible to develop an acceptable correlation of data (the average error being 17.5%) utilising the gassed power consumption and aeration rate per unit volume as key parameters. Since such a correlation succeeded in reconstructing mass transfer rates even in 2.25‐m3 stirred fermenters, it would seem possible to rely on it to allow approximate, but acceptable prediction of kLa values in large size multiple‐impeller fermenters even when geometric similarity in scaling‐up is not maintained.
Prediction of liquid circulation velocity in airlift reactors with biological media
Authors: Chisti Yusuf , Moo‐Young Murray
Published: July 2010

A method is developed and demonstrated for the prediction of liquid circulation velocity in airlift bioreactors operating with pseudoplastic fluids, including mould suspensions. The method is based on a combination of a recently developed energy balance over airlift loops with analytical expressions for shear stress in turbulent or laminar flow of non‐Newtonian fluids. The procedure enables, an a priori calculation of pseudoplastic fluid circulation in airlift devices for design purposes.
Effects of light on the electrical output of bioelectrochemical fuel‐cells containing Anabaena variabilis M‐2: Mechanism of the post‐illumination burst
Authors: Tanaka Kazuko , Kashiwagi Noriko , Ogawa Teruo
Published: July 2010

Bioelectrochemical fuel‐cells containing Anabaena variabilis M‐2 and 2‐hydroxy‐1,4‐naphthoquinone (HNQ) produced electricity in the dark. The current output was increased substantially in the light and a burst of the output current occurred upon darkening. There is a linear relationship between the coulombic output in the burst and the preceding light period. Photosynthetic O2 evolution with HNQ as an electron acceptor and the light‐induced generation of the output current were completely inhibited by 1 × 10−4 mol dm−3 carbonyl cyanide m‐chlorophenylhydrazone (CCCP) but 4 × 10−5 mol dm−3 3‐(3,4‐dichlorophenyl)‐1,1‐dimethylurea (DCMU) inhibited these activities only by 30–40%. Thus, HNQ accepts electrons mainly at the site between photosystem 2 reaction center and QB protein. In the presence of CCCP, the current output was decreased upon illumination and the burst occurred upon darkening. These results suggested that the source of electrons in the burst is a substance(s) accumulated within the Anabaena cells during the light period as a result of inactivation of an enzyme involved in the metabolism of producing output current in the dark.
Interfacial effects in a multistage mixer–settler operation
Authors: Horng Jiin‐Shiung , Lu Daluh , Hoh Ying‐Chu
Published: July 2010

A pilot‐scale mixer–settler with twenty‐one stages was used to investigate the interfacial tension change during extraction cycle for the complicated system: NdCl3–SmCl3–EuCl3–GdCl3–TbCl3–DyCl3–HCl– 1MD2EHPA–kerosene. Interfacial tension, total rate earth (TRE) concentrations in both phases, aqueous acidities, and organic entrainment in the raffinate, etc., were measured for each stage. Murphree stage efficiencies based on organic phase were calculated and related to the interfacial tension profiles. In general, the lower the interfacial tension, the higher the stage efficiency observed. For the extraction section, the stage efficiency ranged from 80%–100%, but for stripping (including scrubbing) section, it varied from 100%–15%. For high acidic stripping agent, 5MHCl, the relatively lower stage efficiency might be due to the protonation of the acidic extractant, therefore the interfacial resistance increased significantly. From the information of stage efficiency, mass transfer direction, and interfacial tension versus solute concentration etc., the Marangoni effect could be used to explain the interfacial phenomena of this complicated extraction system. The results of real stream tests in this investigation will be useful in future plant design.
Cyclohexane dehydrogenation on a nickel catalyst: Kinetics and catalyst fouling
Authors: Al‐Ayed Omar S. , Kunzru Deepak
Published: July 2010

The main reaction and deactivation kinetics of cyclohexane dehydrogenation in the presence of hydrogen has been investigated at atmospheric pressure over a nickel kieselguhr catalyst in the temperature range 583–623 K. The rate of reaction for the fresh catalyst increased with increasing temperature, cyclohexane and hydrogen partial pressures whereas it decreased with an increase in the benzene partial pressure. The experimental data could be adequately modelled by a power law rate expression. The catalyst activity decreased with run time due to catalyst fouling by coke deposition. The rate of deactivation was independent of cyclohexane partial pressure, increased with increasing benzene concentration and decreased with increasing hydrogen partial pressure. It is postulated that coke is most likely formed by the successive dehydrogenation of benzene.
Efficiency of natural oils as antifoaming agents in bioprocesses
Authors: Vardar‐Sukan F.
Published: July 2010

The effectiveness and efficiency of nine different natural oils were investigated using simulated fermentation media and several dimensionless coefficients were derived to provide a means for quantitative comparison. Furthermore, correlations between the physical and chemical properties of natural oils and of media and foam‐suppression efficiencies of natural oils were sought. It was concluded that the effectiveness of a natural oil in foam suppression greatly varies with the type of medium.
A process development for the bundling crystallization of aspartame
Authors: Kishimoto Shin'ichi , Naruse Masayoshi
Published: July 2010

It is known that rod‐like crystals of aspartame, in which several needle crystals appear to be bundled together (bundle‐like crystals), have remarkably improved physical properties compared to the crystals obtained from a conventional stirred crystallizer.

A crystallization process for obtaining bundle‐like crystals has been developed for manufacturing practice. The conditions to obtain the bundle‐like crystals are that crystallization must be carried out without stirring, with a high initial concentration of aspartame so that the amount of precipitated solid after cooling is about 10 g litre−1 or more, and with rapid cooling to produce high supersaturation. A new type of crystallizer was developed for large‐scale crystallization under these conditions. The pilot plant work was carried out in a 400‐litre crystallizer, and it has been demonstrated that the crystallization process is technically possible and economically successful in the large‐scale manufacturing of aspartame.
Methanogenic fermentation of scots pine (Pinus sylvestris) sawdust: Enhancement by physicochemical pretreatment
Authors: Abdul‐Halim Kanaan K. , Balba M. Talaat M. , Senior Eric
Published: July 2010

The three major polymeric components of Scots Pine sawdust–lignin, hemicellulose and cellulose–represent potential substrates for methanogenic fermentation although, in the absence of physicochemical pretreatment, low digestibility was demonstrated even after protracted incubation (18 months). Acid (H2SO4) and alkali (NaOH) pretreatments mediated different effects although, in general, the rates and percent solubilisations increased with concentration, temperature, pressure and time, either singly or in combination. Individual methanogenic fermentations with the hydrolysates and residual solids showed that although 3.3% more methane resulted from the H2SO4 hydrolysate than the corresponding NaOH hydrolysate, in total, 7% more methane was generated from the two alkali fractions than from the corresponding acid fractions.

The results thus exemplified that choice of a specific physicochemical strategy must be made in conjunction with the expected yield from the selected fraction(s).
A study of sintering of magnesium oxide obtained from sea‐water
Authors: Petric Nedjeljka , Petric Bartul , Bogdanić Neven , Mirošević‐Anzulović Meri , Tkalčeć Emilija , Martinac Vanja
Published: July 2010

The process of sintering of magnesium oxide obtained from sea‐water is studied.

The sample thickening stage in the isothermal sintering is determined to establish the manner of pore elimination in the process.

The process of isothermal sintering of magnesium oxide is described mathematically to obtain a better insight into the process, in terms of a function giving the best possible correspondence between theoretical and experimental data.
Mass‐transfer parameters in rotating‐disc contactors: Influence of column diameter
Authors: Korchinsky Walter J. , Ismail Ayham M.
Published: July 2010

Experimental data from rotating‐disc contactors of two diameters (7.6 and 21.9 cm) have been processed using the forward‐mixing model to generate continuous‐phase mass‐transfer and axial‐dispersion coefficients. The mass‐transfer coefficients were found to be correlated through power input. Axial‐disperion effects in the smaller column were too small to allow accurate prediction and comparison with larger‐column values. Only disc speed was proved to have a significant influence on the small‐column results, whereas the larger‐column coefficients also depended on flow rate and the distributor used to control drop size.
Influence of thermal treatment on the porosity and surface characteristics of basic zirconium sulphate
Authors: Gimblett F. Gareth R. , Hussain Asiah
Published: July 2010

Nitrogen adsorption and mercury intrusion methods have been employed to study the influence of thermal treatment over the temperature range 25–800°C on the development of porosity in basic zirconium sulphate. Such treatment leads to the progressive development of mesoporosity in the solid associated with the elimination of bidentate ligands.

All the basic sulphates outgassed at temperatures within the above range exhibit low‐pressure hysteresis in their nitrogen adsorption isotherms as well as a diminution in crystallinity. It is suggested that this indicates a reorganisation at the molecular level brought about by thermal treatment. Not only does this cause the breakdown of the sheet‐like structure of the original solid with the consequent loss of its long‐range crystalline order, but it also leads to the development of mesoporosity in the interstices between the small crystallites generated by such molecular disintegration.
Production of mannitol by Penicillium strains
Authors: Hendriksen H. V. , Mathiasen T. E. , Adler‐Nissen J. , Frisvad J. C. , Emborg C.
Published: July 2010

Eleven different strains of Penicillium were screened for production of mannitol. All strains produced both mannitol and glycerol. Some of the strains also produced arabitol and/or erythritol in lower amounts. The highest amount of mannitol (43 g dm−3) was produced by Pencillium scabrosum IBT JTER 4, and the highest combined yield of mannitol and glycerol (65 g dm−3) was obtained with Pencillium aethiopicumIBT MILA 4 when grown on 150 g dm−3 sucrose and 20 g dm−3 yeast extract. These yields are comparable to yields obtained with Aspergillus strains after a considerable optimization effort. It is thus likely that biotechnological production of mannitol may benefit from the development of suitable Penicillium strains.
Genetic manipulation of laboratory and farm animals
Authors: Bulfield Grahame
Published: July 2010

The development of genetic manipulation in laboratory and farm animals is reviewed. The particular problems of the use of these techniques for modulating commercially important characteristics in farm animals is discussed in detail. The potential hazards of genetic manipulation techniques are evaluated from the view of the welfare of the animals involved and the hazards to other animals and man from the release of transgenic animals into animal breeding practice.
The release of genetically engineered plants and microorganisms
Authors: Beringer John E. , Bale Mark J.
Published: July 2010

Genetically manipulated plants, animals and microorganisms are being released into the environment for research purposes and will soon be released commercially in large numbers. Mankind has considerable experience of the release of unmanipulated organisms and will need to base regulatory procedures for manipulated species on this experience and knowledge of gene transfer and stability. In this article some problems that might be posed by genetically manipulated organisms are discussed.
Prenatal diagnosis
Authors: Bobrow Martin
Published: July 2010

Congenital or genetic disorder may be diagnosed early in fetal life, allowing parental choice as to the continuation of the pregnancy. There are general low cost/low risk screening procedures, and more precisely targetted diagnostic procedures. The techniques used include ultrasound, chromosome and biochemical analysis. The range of diagnosable disorders has been greatly extended by the advent of DNA‐based gene analysis techniques. Ethical and emotional issues are of considerable and continuing importance. The hazards of prenatal diagnosis are misdiagnosis, misinterpretation, and misapplication, and no qualitatively different issues have been introduced by the advent of new biotechnologies.
Bioengineering of hepatitis B vaccines
Authors: Zuckerman Arie J.
Published: July 2010

It has been said that ‘never in the history of human progress has a better and cheaper method of preventing illness been developed than immunisation’. This is well illustrated by the WHO Expanded Programme on Immunisation (EPI), which in developing countries is now preventing nearly a million deaths annually from measles, pertussis, and neonatal tetanus, and for which there is a commitment by the WHO and UNICEF to protect all children by immunisation by the end of the decade. This enormous undertaking will be facilitated by the rapid advances in molecular biology and recombinant DNA technology, in the understanding of immunological mechanisms and by the production and application of monoclonal antibodies so that the structure and location of important antigenic determinants or epitopes can be determined. Chemical synthesis of oligopeptides has been simplified, and computer programmes and X‐ray crystallography provide the tools for the determination of three‐dimensional structure of proteins, so that the structure and location of important antigenic determinants or epitopes can be predicted.

These techniques have opened the way to the improvement of existing vaccines and to the development and production of new vaccines against infections for which vaccines are not available.

New vaccines under development include vaccines against hepatitis B, hepatitis A, malaria, vaccines for typhoid, cholera, rotavirus infection and other diarrhoeal diseases, leprosy, rabies, fertility regulating vaccines and the acquired immune deficiency syndrome (AIDS).
Securing safety
Authors: Vere D. W.
Published: July 2010

To secure safety it is essential to know risks and to understand them. There are many problems in understanding risks related to drug effects. These include problems at the scientific level and among the community. The latter includes the singular problem that the general understanding of risk is of one kind, whereas the legal understanding of it is different. Examples are given and discussed of difficulties at each of these levels and some analysis made of ethical duty on the part of research workers, manufacturers and society at large in relation to each of them.
Sorption of caesium by hexacyanocobaltate(III)
Authors: Mekhail Fikry M. , Ibrahim George S. , Aly Hisham F.
Published: July 2010

Sorption properties of the commercially available hexacyanocobaltate(III) complex with respect to the retention of caesium have been studied. The saturation capacities are determined from the adsorption isotherms in solutions of pH 6.5, in M HNO3 and in simulated medium‐active waste. The solubility of Co(II) hexacyanocobaltate(III) in acid and in alkaline solutions indicates its stability in acid medium. The sorption of caesium on hexacyanocobaltate(III) complex seems to proceed via an ion‐exhcnage mechanism.
Cell manipulation in ultrasonic standing wave fields
Authors: Coakley W. Terence , Bardsley David W. , Grundy Martin A. , Zamani Freidoun , Clarke David J.
Published: July 2010

Particles suspended in either travelling or standing wave fields experience non‐zero time averaged radiation forces. In a standing wave field such forces can result in migration of the particles to preferred positions separated by distances of half an acoustic wavelength. Radiation forces also give rise to either interparticle attraction or repulsion and can exert a torque on suspended particles. The forces depend on some or all of the following properties (i.e. particle size and shape, sound frequency, the square of the sound pressure amplitude) and on the differences between the density and compressibility of the particles and those of the suspending phase. The forces acting on suspended particles are analysed and threshold pressures for the migration of particles to half‐wavelength separations are derived. It is shown that appropriate choice of sound pressure amplitude should lead either to separation of particles of different densities and compressibilities in the sound field or to concentration of mixed samples essentially at the same location. Experimental observations of ultrasonic radiation force effects on cells are reviewed as are applications of radiation forces to effect cell concentration in electrofusion procedures and the use of ultrasound to support cells away from solid surfaces. Examples of cell concentration, cell alignment and cell‐cell interaction are presented.
Extraction and characterisation of extracellular polymers in digested sewage sludge
Authors: Karapanagiotis Nicolas K. , Rudd Thomasine , Sterritt Robert M. , Lester John N.
Published: July 2010

Five different bacterial extracellular polymer extraction methods were compared on digested sewage sludge. A washing step was necessary to remove and eliminate the slime from the sludge sample, in order to distinguish it from the material more tightly bound to the sludge solids. An ion‐exchange resin method was the most effective and least disruptive of all treatments tested, based on the relatively high extracellular polymer yield and the small amount of cell disruption demonstrated by the fractionation and characterisation of the extracted material.

The extracellular polymer extracted contained protein and polysaccharide in a ratio of approximately 3:1, and contributed a relatively small proportion of the total solids in digested sludge. This was comparatively less than is extracted in activated sludge. The ion‐exchange resin method yielded 1% by weight of polysaccharide and 3% of protein, whereas ethanol‐insoluble material accounted for 3.5% of the solids in digested sludge.
Comparison of alkali and steam (acid) pretreatments of lignocellulosic materials to increase enzymic susceptibility: Evaluation under optimised pretreatment conditions
Authors: Fox David J. , Gray Peter P. , Dunn Noel W. , Marsden Warwick L.
Published: July 2010

The alkali pretreatment of sugar cane bagasse was optimised and compared with an optimised steam (acid) pretreatment. The optimised alkali pretreatment gave an overall sugar yield of 37.4 g sugars per 100 g bagasse accounting for 43.8% of the initial xylan and 64.5% of the glucan. Potential effluent problems were identified with the alkali treatment and several strategies were suggested to minimise them, with liquor recycling showing some promise. The optimised steam (acid) pretreatment gave an overall sugar yield of 55.7 g sugars per 100 g bagasse accounting for 76.5% of the xylan and 89.5% of the glucan. The superiority of the steam (acid) pretreatment over the alkali pretreatment depends on the ability to utilise the xylose produced.
Spectrophotometric determination of nickel in steels
Authors: Zaki M. Tarek M. , Sedra M. N. R. , Attiya S. M.
Published: July 2010

New, simple and sensitive spectrophotometric methods for the determination of nickel with hematoxylin in the presence and absence of a cationic surfactant are described. The sensitivity of the color reaction of nickel and hematoxylin is greatly increased by the sensitizing action of cetyltrimethylammonium bromide (CTAB). The optimum pH range for the formation of nickel‐hematoxylin and nickel‐hematoxylin‐CTAB systems is 7.8–8.3 and 7.4–8.1, respectively. The molar absorptivities are 4.1 × 104 and 8.3 × 104 mol−1 cm−1 at 595 and 608 nm, respectively. The corresponding values of Sandell's sensitivity index are 0.0014 and 0.0007 μg cm−2 of nickel. The methods adhere to Beer's law up to 0.52 and 0.60 ppm nickel, respectively. The mole ratio of nickel‐hematoxylin in both complexes is 1:2. Preliminary separation of nickel by extraction as dimethylglyoxime chelate into chloroform makes it possible to determine nickel in steel samples.
A new spectrophotometric method for the determination of ferrous iron in the presence of ferric iron
Authors: Herrera Leandro , Ruiz Pauline , Aguillon Juan C. , Fehrmann Alexis
Published: July 2010

A new spectrophotometric method for the determination of ferrous iron concentration in samples containing ferric iron is presented. This new method is a modification of the Muir o‐phenanthroline ferrous iron determination method.

The new method consists of the quantitative spectrophotometric determination of Fe(II) by o‐phenanthroline, but in which the ferric iron is complexed with sodium fluoride to eliminate interferences.

A critical experimental comparison between the Muir spectrophotometric method, the Kolthoff titrametric method and the new proposed method is presented. Whenever Fe(III) accounts for more than 50% of the total iron in a sample, the method of Muir overestimates Fe(II).

The proposed method has a range of 1–10 μg ferrous iron. It is as insensitive to other metal ions as the original method of Muir and is insensitive to Fe(III) up to a point where Fe(III) might be as high as 95% total iron.

The proposed method is suitable for Fe(II) determination in bacterial leaching systems, where Fe(II) might be as low as 1% of total iron.