Toms Effect in Model and Real Systems

Selected data on use of macromolecular compounds (polymers) as additives that diminish the hydraulic resistance of turbulent fluid flows (Toms effect) are presented. Theoretical and applied (concerning mainly oil production) aspects of the phenomenon are considered.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 4, 2005, pp. 529–544.Original Russian Text Copyright © 2005 by Myagchenkov, Chichkanov.     

Kinetic Regularities of Reactions of O,O-Diaryl Phosphorohydrazidothioates with Phenyl Isothiocyanate in Benzene

The effect of the temperature on the rate of reactions of O,O-diaryl phosphorohydrazidothioates with phenyl isothiocyanate in benzene is studied, and the activation parameters of the reactions are calculated. It is established that the reaction series under study obeys the isokinetic relationship with an enthalpy control and an isokinetic temperature of 690±24 K. The effect of electronically diverse substituents on phosphorus on the reactivity of O,O-diaryl phosphorohydrazidothioates is additive. It is described by the Hammett equation with σ^P constants.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 6, 2005, pp. 893–896.Original Russian Text Copyright © 2005 by Yanchuk, Ivanets.     

Effects of Congo red on the drag reduction properties of poly(ethylene oxide) in aqueous solution based on drop impact images

The presence of very small amounts (ppm) of high-MW polymers in solution produces high levels of drag reduction in a turbulent flow. This phenomenon, often termed as the Toms effect, is highly dependent not only on MW, but also on the flexibility of the macromolecular chain. The Toms effect can be studied through the images of the structures produced after the drop impact against shallow solution surfaces. The splash structures composed of crown, cavity, and Rayleigh jet are highly dependent on the elongational properties of the solution. This work presents the effects of Congo red on the drag reduction properties of poly(ethylene oxide) in aqueous solutions through the analysis of splash structures. Results obtained in this analysis indicate that Congo red molecules act as physical cross-linking agents, decreasing the polymer elasticity and its drag reduction capacity. It was observed that the maximum height of the Rayleigh jet can be used as a sensitive parameter to the complexation between the dye and the polymer molecules.     

Kinetic salt effects in the reaction of permanganate ions with iodide ions in concentrated electrolyte solutions

The oxidation of iodide ion by permanganate ion has been studied in several electrolyte solutions over the concentration range (0–6M). The observed kinetic salt effect may be interpreted as arising as a result of ionsolvent interactions. This salt effect is additive for different salts. Support for these conclusions comes from an examination of the activity coefficients of species estimated from the treatment given by Pitzer. It has also been shown that the species relevant in terms of kinetic control are unassociated.     

Processes in a Nickel-Zinc Battery with a Negative Electrode Containing a Calcium Hydroxide Additive

The influence exerted by a calcium hydroxide additive introduced into the negative electrode on the serviceability of a sealed nickel-zinc battery with a nickel oxide electrode fabricated from spherical nickel hydroxide on a foamed-nickel support was studied.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 3, 2005, pp. 428–432.Original Russian Text Copyright © 2005 by Arkhangel’skaya, Krasnobryzhii, Kas’yan, Loginova, Vinogradova.     

Electrodeposition and characterization of chromium–tungsten carbide composite coatings from a trivalent chromium bath

The electrodeposition of chromium from a trivalent chromium bath has been described in this work. The electrocomposite coatings of chromium with hard abrasive particles were investigated. The chromium–tungsten carbide (Cr? WC) composite coatings were obtained by suspending different concentrations of WC particles in a trivalent chromium plating solution to improve the various properties of the chromium deposit layers. The effect of operating conditions on the deposit layers has been studied. On the other hand, the effect of non‐ionic polymeric surfactant [nonyl phenol ethoxylate with 12 units of ethylene oxide (NPE)] as an additive in enhancing the incorporation of the WC ceramic particles in the chromium metal matrix was investigated. It was found that the co‐deposition of the WC ceramic particles depends on the concentration of the additive and its efficiency in reducing the surface tension of the electroplating solution. The mechanism of incorporation of WC particles into a growing deposit was suggested and discussed in view of the zeta potential and degree of wetability of WC particles in the plating solution. Furthermore, the adsorption behaviour of the additive on WC particles was analysed according to the Frumkin isotherm. The surface morphology and the distribution of WC in the chromium metal matrix were investigated. The properties of the deposit layers, hardness, corrosion resistance and wear resistance were determined and compared with free chromium deposits. The test results reveal that the Cr? WC deposit layer shows better performance compared with the chromium‐free deposit. Copyright © 2005 John Wiley & Sons, Ltd.     

A Voltammetric Study of the Kolbe Synthesis with Perfluorinated Oxa Acids: Influence of the Structure of the Fluorocarbon Residue

The Kolbe synthesis with two perfluorinated oxa acids, perfluoro-3,7-dioxa-2-methyloctanoic and perfluorotetrahydro-α-furylacetic, was studied voltammetrically on platinum and glassy carbon anodes in water-acetonitrile and methanol-acetonitrile solutions. The influence exerted on the process by the acid concentration, degree of its neutralization, and solvent was studied. The solvent-anode system exerts a differentiating effect on the reactivity of perfluorinated acids under the conditions of the Kolbe synthesis.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 5, 2005, pp. 762–767.Original Russian Text Copyright © 2005 by Chechina, Tomilov, Sokolov.     

Effect of sucrose on BSA denatured aggregation at high concentration studied by the iso-conversional method and the master plots method

The kinetics of protein thermal transition is of a significant interest from the standpoint of medical treatment. The effect of sucrose (0–15 mass%) on bovine serum albumin denatured aggregation kinetics at high concentration was studied by the iso-conversional method and the master plots method using differential scanning calorimetry. The observed aggregation was irreversible and conformed to the simple order reaction. The denaturation temperature (T _m), the kinetic triplets all increased as the sucrose concentration increased, which indicated the remarkable stabilization effect of sucrose. The study purpose is to provide new opportunities in exploring aggregation kinetics mechanisms in the presence of additive.     

Rheological Properties of Blends of Ternary Copolyamide 6/66/610 with Chitosan

The viscosity of melts of a blend of a ternary copolyamide 6/66/610 and polysaccharide (chitosan) used as biodegradable additive was determined by capillary viscometry at 150–170°C.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 6, 2005, pp. 989–992.Original Russian Text Copyright © 2005 by Suvorova, Tyukova, Smirnova, Tymchishina.     

Using hydrophobic additive as pore‐forming agent to prepare macroporous PNIPAAm hydrogels

Hydrophobic poly(lactic acid) nanospheres were fabricated and used as an additive during the polymerization and gelation process of temperature‐sensitive poly(N‐isopropylacrylamide) (PNIPAAm) hydrogels. The influence of hydrophobic additive on properties of PNIPAAm hydrogels was examined. The interior morphology studied by scanning electron microscopy revealed that the hydrophobic additive induced a macroporous structure in the resulting PNIPAAm hydrogels. Results demonstrate that the hydrophobic additive acts as a pore‐forming agent like conventionally used hydrophilic additive does during the gelation process. Because of the macroporous network and incorporated additives, the temperature‐sensitive characteristics, particularly the equilibrium swelling ratio at room temperature and shrinking rate upon temperature increase of modified PNIPAAm hydrogels, are significantly improved. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5490–5497, 2005     

Effect of concentration of ammonia and citrate ions on the kinetics of cathodic reactions during electrodeposition of a nickel-molybdenum alloy

The effect of the concentration of ammonia and citrate ions on the kinetics of cathodic processes in electrolytes intended for depositing electrolytic coatings of a nickel-molybdenum alloy is studied. Conditions conducive to obtaining coatings of satisfactory quality are formulated. The effect of ammonia and citrate ions on the Mo content in the alloy is analyzed. The experimental data are explained by assuming that the intermediate products of reduction of nickel and molybdate ions are adsorbed on the electrode surface.To the Centennial of B.N. Kabanov.Translated from Elektrokhimiya, Vol. 41, No. 1, 2005, pp. 83–90.Original Russian Text Copyright © 2005 by Kuznetsov, Pavlov, Chepeleva, Kudryavtsev.     

Synthesis of Monodisperse Polystyrene Particles in the Presence of Sodium Dodecyl Sulfate and Carboxyl-containing Initiator

Emulsion polymerization of styrene in the presence of an anionic surfactant, sodium dodecyl sulfate, in a concentration close to the critical micellization concentration, was studied, as influenced by the pH of the initial reaction mixture and the content of the carboxyl-containing azoinitiator.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 6, 2005, pp. 1029–1033.Original Russian Text Copyright © 2005 by Men’shikova, Evseeva, Shabsel’s, Balanina, Sirotkin, Ivanchev.     

Toms Effect as Influenced by the Glass Capillary Length and Diameter

The degree of reduction of the hydraulic resistance was studied as influenced by the concentration of the anionic copolymer of acrylamide, geometric parameters of the contour, and turbulent flow velocity.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 4, 2005, pp. 669–672.Original Russian Text Copyright © 2005 by Chichkanov, Myagchenkov.     

Synthesis and Pore Structure of Monolithic Polymeric Sorbents

The pore structure of monolithic sorbents prepared by photoinduced copolymerization of 2,3-epoxypropyl methacrylate with ethylene glycol dimethacrylate was studied. The parameters of the pore structure of these copolymers were examined as influenced by the quantitative ratio of pore-forming agents and the type and concentration of the initiators.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 4, 2005, pp. 623–628.Original Russian Text Copyright © 2005 by Khimich, Rakhmatullina, Slabospitskaya, Tennikova.     

Determination of the Working Exchange Capacity of Weakly Basic Polyacrylic Anionites

The nonequilibrium dynamics of sorption of hydrochloric acid by weakly basic polyacrylic anionites was studied. An equation for calculating the working capacity of ion-exchange filters as a function of variable parameters (filtration rate, concentration of the starting solution, and height of the ionite bed in a filter) was derived using the theory of nonequilibrium dynamics of sorption.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 6, 2005, pp. 905–911.Original Russian Text Copyright © 2005 by Mamchenko, Savchenko.     

LW-1型增效剂对聚丙烯酰胺水溶液增粘的实验研究

研究了LW 1型增效剂对聚丙烯酰胺水溶液的增粘效果 ,考察了增效剂含量、溶液中金属离子浓度、剪切强度、聚合物浓度、pH值对增粘效果的影响 .结果表明 ,增效剂能起到显著的增粘效果 ,对提高原油采收率具有重大意义 .此外 ,初步分析了LW 1型增效剂对聚丙烯酰胺水溶液增粘的可能机理     

Barium Sulfate Effects on the Electrochemical Behaviors of Nanostructured Lead Dioxide and Commercial Positive Plates of Lead-Acid Batteries

Positive electrode with uniform lead dioxide nanostructures directly synthesized by cyclic voltammetry (CV) method on the lead substrate in 1 M sulfuric acid solution including different concentration of barium sulfate. The effect of potential scan rate, sulfuric acid and barium sulfate concentration were studied on the morphology and particle size of lead dioxide using scanning electron microscopy (SEM) and X-ray diffraction techniques (XRD). The effect of barium sulfate was studied on the CV parameters including anodic peak current (I _p^a), cathodic peak current (I _p^c), anodic peak potential (E _p^a) and cathodic peak potential (E _p^c) during synthesis process. Finally, the effect of barium sulfate on the discharge capacity and cycle life of nanostructured positive electrodes and commercial positive plates was investigated. Both CV and battery test results showed that barium sulfate with concentration of 1 × 10⁻⁵ M can be used as suitable additive for positive paste of lead-acid batteries.     

Spectrophotometric Determination of Proline in Aqueous Solutions

The spectrophotometric determination of proline in aqueous solutions was studied. It was shown that pH, concentration, and time of storing the solution affect its spectral properties.__________Translated from Zhurnal Analiticheskoi Khimii, Vol. 60, No. 8, 2005, pp. 802–805.Original Russian Text Copyright © 2005 by Davydova, Kotova, Krysanova, Selemenev.     

Structure and Temperature Effects on the Reaction Rate of Aryloxiranes with 3,5-Dinitrobenzoic Acid in Acetonitrile

The effects of temperature and structure of aryloxiranes on the rate of their reaction with 3,5-dinitrobenzoic acid in acetonitrile are additive, and the process is entropy-controlled.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 7, 2005, pp. 1011–1014.Original Russian Text Copyright © 2005 by Shpan’ko, Sadovaya.     

The Effect of Composition of Water-Ethanol Solutions on Coagulation Kinetics of Amorphous Monodisperse Silica Suspensions

The effect of the composition of water-ethanol solutions on the coagulation kinetics of dilute amorphous monodisperse silica suspensions is studied using flow ultramicroscopy technique. It is found that the suspensions prepared by the addition of an aliquot of concentrated and stored for more than 20 days suspension of the aforementioned silica in 96% ethanol to water-ethanol mixtures containing 96–80 vol % of ethanol are stable with respect to aggregation. A decrease in the alcohol concentration in a system leads to an ultrafast coagulation, whose characteristic time (coagulation period) is much smaller than the value corresponding to the Smoluchowski theory of fast coagulation. It is established that the highest coagulation rate is observed for the suspensions containing 40 vol % of ethanol. Mechanisms of the aggregation stability and ultrafast coagulation of the studied suspensions are discussed.__________Translated from Kolloidnyi Zhurnal, Vol. 67, No. 4, 2005, pp. 475–478.Original Russian Text Copyright © 2005 by Zhukov, Zavarovskaya, Chernoberezhskii.