Effect of Some Organic Compounds on Composition of Products of Spark Dispersion of Aluminum

The influence exerted by the nature of organic components of the working solution on the composition of products formed in spark dispersion of aluminum was studied.     

Phonon Dispersion Curves of Some Liquid Metals Based on the Percus-Yevick Phonon Description

Abstract

Phonon dispersion curves are almost quantitatively predicted by a first-order theory based on a zeroth order model of independent density fluctuations. The temperature dependence of the liquid structure factor at constant volume is important for the present considerations.     

Magnetoelectrolytic Dispersion of Ferromagnetic Metals

Processes of electrolytic dispersion of ferromagnetic metals (nickel and cobalt) to give oxides or metal powders were studied. The influence of an external magnetic field and current reversal on the processes of anodic dissolution was analyzed.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 6, 2005, pp. 924–927.Original Russian Text Copyright © 2005 by Zaichenko.     

Spark Dispersion of Aluminum and Its Subsequent Hydration

The influence exerted by components introduced into the working solution and by the temperature of sludge treatment on hydration of dispersed aluminum particles formed in the course of spark erosion was studied.     

Formation of Metal Powder in Spark Dispersion of Aluminum

The effect of additives introduced into the working solution on the behavior of dispersed aluminum particles formed in spark erosion was studied. The conditions under which products of a given composition are formed were determined on the basis of thermodynamic and kinetic factors.     

Some Emulsion Features

Traditionally, emulsions have been defined as consisting of two liquids, of which one is dispersed in the other as macroscopic drops, stabilized by mono‐molecular layer of surfactant at the interface. However, a large majority of commercial emulsions are more complex than so and the added elements are essential for the properties of the emulsions including their stability.

With this in mind, this treatment of emulsions is divided into emulsions with mono‐layers and multilayers at the interface. In addition, additional elements in emulsions are described; such as lyotropic liquid crystals, vesicles, microemulsion droplets and solid particles, and their potential influence on the emulsion properties is indicated.     

世界化学与社会课程的几个特点

1985年,国际科学联合会的理科教学委员会在印度的班加罗尔召开了科学和技术教育以及未来人类需要的会议,主要目的是:鉴定和探索科学和技术教育中的一些领域,这些领域在为未来的工人和市民提供现实意义的教育上是特别重要的。经鉴定的八个领域是:健康;食物和农业;能源;陆地;水和矿物资源;工业和技术;环境;信息传递和技术、伦理学和社会责任。这八个单元几乎都跟化学有紧密的联系。     

Dispersion of Waxy Gas Oil by Some Nonionic Surfactants

Straight chain fatty alcohols having the following number of carbon atoms–C₁₂, C₁₄, C₁₈, and C₂₁–each alcohol were ethoxylated to the same of ethylene oxide content, characterized through average molecular weight and elemental analysis. The surface properties of these compounds were studied through surface tension measurements. The synthesized additives were tested as flow improvers for improving the cold flow properties of two waxy gas oils through pour point test. The results show the right efficiency of these compounds in improving the flowability. Comparative evaluation of the synthesized products with available commercial additive (com) showed their efficiency and suitability to use in gas oils. Wax modification was assisted through photoanalysis. Correlation between wax modification and flow improvement in term of pour point depression appeared to be merely qualitative in such heterogeneous gas oil systems.     

某些有机物在氧化物载体表面的自发单层分散

自发单层分散原理已在载负型催化剂制备、再生等方面得到越来越广泛的应用[1，2]．许多氧化物和盐类可以在载体表面形成单层分散或亚单层分散．有些分散物与载体混合后在低于其熔点的温度下处理，就可以自发分散到载体表面[1，3]．这一现象通过XRD、LRS、XPS、SIMS、ISS、EXAFS     

Thermal Stability of Bis-Piperidine Benzoylacetonates of Some Transition Metals

Bis-piperidine complexes of benzoylacetonates of Mn(II), Co(II), Cd(II) and Ni(II) were prepared. Thermogravimetric analysis (TG) demonstrated that Mn(II) bis-piperidine benzoylacetonate was stable up to 90°C, while Co(II) bis-piperidine benzoylacetonate was stable up to 100°C, whereas Cd(II) bis-piperidine benzoylacetonate was stable up to only 50°C. Its first decomposition step was completed at 110°C. Ni(II) bis-piperidine benzoylacetonate found to be stable up to 110°C. The stabilities of the complexes of these metals therefore follow the sequence Cd²⁺<Mn²⁺<Co²⁺<Ni²⁺. The complex of Cd(II) was the least stable of all the compounds studied.This revised version was published online in November 2005 with corrections to the Cover Date.     

Kinetics and Determination of Some Transition Metals with Peri-Dihydroxynaphthindenone

Abstract

A simple sensitive and selective spectrophotometric method has been developed for determination of some transition metal ions. It is based on the reaction of the metal ions with excess peri-dihydroxynaphthindenone in 80% v/v ethyl alcohol-water mixture at 30°C. The colored products obtained display maximum absorption band at 560–590 nm depending upon the type of transition metal ion used, and E_{1 cm} ^1% in the range 70–480. Under the optimum conditions results with an average recovery of 96%, (mean standard deviation ±3% are obtained for 6 different transition metal ions without any significant interference from Li⁺, Na⁺, K⁺, Cs⁺, Rb⁺, Ba²⁺, Sr²⁺, Ni²⁺, Bi³⁺, Co²⁺, Mn⁺², Cd⁺² and Al⁺³. Kinetic data reveal that the reaction proceeds via a second order route (first order with respect to either the metal cation or ligand). The activation parameters and a suggested mechanism have been presented, and the nature of bonding in the solid chelate products has been verified.     

High Voltage Spark Excitation of Some Organic Molecules in Nitrogen and Argon Atmospheres

Abstract

A simple high voltage ac spark produced between tungsten electrodes in both nitrogen and argon atmospheres is investigated as an emissive detector for certain organic molecules. Volatile vapours entering the electrode gap lower the resistance and an increased current flows in the spark. The energy available, particularly using nitrogen as a carrier gas, is sufficient to excite UV/visible spectra for various organic compounds; carbon species may be detected at 389 nm (CN), sulphur compounds at 257 nm (CS), halogenated compounds at various tungsten atomic lines and iodine at 206.2 nm (iodine atomic).     

Quinaldic Acid Complexes with Some Trivalent Rare Earth Metals

The Polarographic behaviour of quinaldic acid in the presence of lanthanide cations (Kd³⁺, Gd³⁺, Er³⁺) is studied at pH=4.5 and 0.1 M HClO₄ as supporting electrolyte. The polarographic reduction gives two waves at lower concentrations of quinaldic acid and three waves at higher concentrations. The nature of the waves was investigated. The dissociation constant of quinaldic acid as well as the stability constants of some lanthanide cation complexes with quinaldic acid were determined potentiometrically in 75% (v/v) dioxane-water at 25°C and 0.1 M KNO₃. The solid complexes of Nd, Gd and Er were isolated and studied by ir, differential thermal analysis (DTA) and thermogravimetric analysis (TGA) techniques.     

Methane Pyrolysis for Hydrogen Production: Specific Features of Using Molten Metals

Russian Journal of Applied Chemistry - Published data on noncatalytic pyrolysis of natural gas in molten metals are analyzed. The most illustrative results obtained in the past two decades are...     

Reversible Transition of Polyphosphate Glasses of Some Bivalent Metals to Tetrametaphosphates

Abstract

Conditions and reversibility have been determined of the transition of amorphous polyphosphate glasses Fe^II, Cu^II, Ba^II, Sr^II to crystalline tetrametaphosphates. This recrystallization process was followed by the methods of thermal analysis (DTA, TG, DSC, TMA) in an inert atmosphere and in air. The temperatures of penetration and recrystallization, and values of activation energies and heat of the phase transformation have been estimated. Yield of the process has been determined by methods of instrumental analysis and by the extraction methods developed in our laboratory. The process is markedly affected by the atmosphere. Lattice parameters of the tetrametaphosphates obtained by the recrystallization have been determined and compared with those of the products synthetized by the classical thermal procedure (ref. 1). On the basis of the recrystallization of polyphosphate glasses, we have suggested procedures of effective introduction of admixtures into the tetrametaphosphate structure (ref. 2). They are used, inter alia e.g. for preparation of a luminophore (ref. 3) which exhibits an intensive emission of blue and yellow radiation and can be applied in construction of fluorescent lamps.     

Effect of Colloidal Dispersion of Clay on Some Properties of Wool Fiber

This work was carried out to characterize the changes induced on wool fiber by clay treatment. Technical measurements were studied including Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermal degradation analysis (TGA), scanning electron microscopy (SEM), moisture regain measurement (MRM), and tensile strength test (TST). The intensity of major peaks in FTIR spectra of the clay treated sample is in favor of chemical changes of the polypeptide functional groups. DSC results indicated that clay treatment of wool enhances heat and thermal barrier properties of fiber. TGA results stated lower thermal degradation of clay treated wool compared with untreated one. One of the main advantages of clay application on wool could be its positive effect on the moisture absorption of wool.     

Estimation of Residual Nickel and Some Heavy Metals in Vanaspati Ghee

To convert vegetable edible oils into vanaspati ghee, nickel is used as a catalyst in the hydrogenation process. A simple and fast method for the trace level determination of nickel in ghee is reported. In this work different methods were applied for the extraction of residual nickel from ghee samples. Using toluene, benzene and carbon tetrachloride as organic solvents, an acid mixture was used for the extraction of nickel. Extracted nickel was quantified with atomic absorption and colorimetric methods. Among the organic solvents, toluene proved to be the best solvent mediating a 95% extraction of nickel from ghee samples. Nickel was extracted and determined in ten different brands of ghee and in all samples its amount was well above the permissible limit of WHO (0.2 μg/g). Other metals like lead, zinc, copper, and cadmium were also determined and their concentrations were found to be much below the WHO permissible limits.     

Behavior of Aluminum in Its Electric-Spark Dispersion in Aqueous Solutions of Some Acids

The influence exerted by the nature and concentration of a number of organic and mineral acids on the composition of products formed in electric-spark dispersion of aluminum was studied.