Characterization of Grain-Boundary Segregation in MgO

Using Auger electron spectroscopy, segregation of Ca and Si corresponding to the adsorption of a partial monolayer adjacent the boundary in polycrystalline MgO was observed. Segregation of Sc is different in nature; the distribution consists of a 3.0-nm wide region corresponding to a positive space charge layer balancing a negative boundary charge. Various segregation models are applied to the observed behavior.     

A Viscosity-Temperature Relation for Glass

A theory for the viscosity and structure of glass as a function of temperature and composition had been advanced, proposing that at a few critical temperatures silicate glasses undergo structural transformations. Between these transformation temperatures, the activation energy and lattice coefficient are constant. A series of special glasses were melted and viscosity was measured to test this theory. The results indicate that the viscosity-temperature behavior of glass does not conform to the previously proposed model. The activation energy appears to vary continuously over the entire temperature range studied. However, a critical temperature does exist at which the temperature coefficient of the activation energy changes. This discovery represents a more subtle change than that previously envisaged.     

Cold water detergency studies using radiolabeled soils

The effects of single and multiple washing and of resoiling-rewashing of cotton and synthetic fabrics have been studied in Tergotometer tests at various levels of temperature, detergent concentration and water hardness. The soiling mixture consisted of a seven component sebum tagged with tritium and carbon-14; in some tests gammaray emitting Kaolinite clay was also used. Linear primary alcohol ethoxylate (LAEO) and linear alkylbenzene sulfonate (LAS) were used for surfactant type comparisons. In single wash tests in both hot and cold water, LAEO was generally more effective than LAS in removing sebum. This was particularly noticeable at low product concentration where insufficient sodium tripolyphosphate was present to sequester the water hardness. A 1/1 blend of the two surfactants approached LAEO in performance. The nonpolar sebum fraction was more readily removed from Dacron or nylon in cold water; otherwise, detergency was generally better at high temperatures. In rewash tests, using labeled lube oil, cholesterol and clay, a progressive increase in soil removal was found during five wash cycles. The nonpolar lube oil component was the most difficult to remove from permanent press Dacron-cotton (PP), but was more readily removed from cotton. The more polar cholesterol and especially the clay were more easily removed from PP. LAEO gave better detergency both hot and cold than LAS, especially in hard water. On cotton swatches resoiled with sebum after each wash the residual sebum content was still increasing after five cycles. With PP in soft water, a steady state was reached after three to five cycles. Soil buildup was greater as hardness increased and as wash temperature and active matter concentration decreased, and was generally greater on cotton than on PP. LAEO allowed appreciably less soil buildup than did LAS especially at low concentration in hard water, indicating a reduced requirement for sodium tripolyphosphate. Presented before the AOCS Meeting, New Orleans, April 1970.     

Azo disperse dyes with polyfluoroalkyl groups attached to the nitrogen atom of the coupling component

A number of new azo disperse dyes with polyfluoroalkyl groups attached to the nitrogen atom of the coupling component have been prepared. The influence of polyfluoroalkyl groups on the colour and properties of azo dyes has been studied. The replacement of hydrogen atoms of the methyl group of the coupling component by polyfluoroalkyl radicals causes a hypsochromic shift of absorption maximum in a neutral solution and deepening of the dye colour in an acid solution. All tested dyes showed a high lightfastness on acetate and polyamide fibres.     

Preparation and properties of high molecular weight poly(1-germa-) or poly(1-sila-cis-pent-3-enes)

High molecular weight poly(1,1-dimethyl-1-germa-cis-pent-3-ene), poly(1,1-diphenyl-1-germa-cis-pent-3-ene), poly(1,1-dimethyl-1-sila-cis-pent-3-ene), and poly(1-methyl-1-phenyl-1-sila-cis-pent-3-ene) have been prepared. The thermal stability of these polymers is found to increase with their molecular weight.     

Trends in industrial markets for fats and oils and derivatives

During the past decade, research by industry and government has developed numerous new chemical markets for fats and oils derivatives. Lower prices for competitive raw materials have forced some of these new products into specialty markets. Economic factors, such as the continual growth of the chemical industry, population increases, and high consumer demand, have allowed for steady growth in the fat-derivative market. New fat-type plasticizers are currently consuming about 60 million pounds of fats annually. Synthetic lubricants will probably be consuming 20 million pounds of fatty diesters annually by 1965. Animal feeds consume approximately 600 million pounds of fats and fat derivatives annually and may eventually become the leading domestic nonfood market for fats. The protective coating market as an outlet for fats continues to decline, and the continuing shift to nonfat materials and changes in pain formulas indicate that, while the demand for protective coatings may increase, the use of fats in their manufacture may not share in the increase. Nonfat chemical raw materials provide intense price competition for fatty raw materials. Fat prices are influenced by the demand for use in food, soap, paints, and possibly animal feeds rather than by the demand for use as chemical raw materials. Presented before the American Oil Chemists' Society, New York, October, 17, 1960.     

Thermal Decomposition of Europium Hydroxide

The thermal decomposition of europium hydroxide in an air atmosphere was investigated by means of weight-loss measurements, infrared spectroscopy, X-ray diffraction analysis, and electron microscopy. These studies showed that EU(OH)° decomposed at temperatures between 225° and 300°C into EuOOH, which was stable up to about 425°C. Between 435° and 465°C this compound decomposed into cubic Eu₂O₃, which was stable until its inversion to the high-temperature monoclinic form. X-ray diffraction data were collected for Eu(OH)₃ and EuOOH and showed that the trihydroxide has a hexagonal crystal structure and the oxyhydroxide is possibly orthorhombic. The Eu(OH)₂, EuOOH, and cubic EunOa powders contained particles up to several microns in size consisting of agglomerates of crystallites in the size range 200 to 400 A. The single monoclinic Eu₂O₃ sample studied contained crystallites whose average size was greater than 2000 A.     

The cycling behaviour of zinc electrodes in a nickel oxide-zinc accumulator

The behaviour of porous zinc electrodes was investigated by monitoring the potential distribution along the surface of the electrode during charging and discharging in a nickel oxide-zinc battery. Impedance measurements of the zinc electrode were taken as a function of state-of-charge and of the cycle number. The composition of the electrode was varied with HgO and PbO additives. Shape change was observed for all electrodes. The observed potential distribution has led to the tentative explanation that the shape change phenomenon is caused by diffusion of zincate along the surface.     

A single phase model of mechanisms effecting miscible surfactant oil recovery

The concept of volume averaging is used to theoretically study the mechanisms of mass dispersion, adsorption, and dead-space volume. These mechanisms are important to the understanding of miscible surfactant flooding. After simpiffication based on order-of-magnitude scaling, a linear core model is solved using state variable finite-difference techniques. Mass dispersion and adsorption are shown to be important model parameters while dead-space volume is a rather insensitive model parameter.     

Electrochemical properties of anodic gold oxide layers—I: Potentiostatic oxide growth and double layer capacity

The potentiostatic growth of gold oxide layers was investigated at pH = 0, 2, and 6.2 in the potential range 1.4 V ? ? ? 2.3 V (vs hess) and for polarization times between 10^?4 and 10³ s. At ? < 2.0 V the growth of monomolecular oxide layers (oxide 1) with a thickness up to 10 Å was observed. This process takes place according to a high field mechanism. In this range, the double layer capacity decreases with increasing thickness d. With increasing ? there is a continuous change of oxide growth.At ? > 2.0 V a potential dependent linear growth law is observed with the formation of thick layers (oxide 2) up to 600 Å or more. In this range, further peaks arise in the cathodic charging curves, and the double layer capacity becomes independent of d.It follows that on the monomolecular boundary layer (oxide 1) the bulk oxide 2 is formed, which has a good ionic and electronic conductivity. Hence, the potential drop is small in oxide 2, but large in oxide 1. Even at high potentials the rate-determining step is the field dependent ionic migration in oxide 1.