Kind Of Alkali Research Articles

Nonstoichiometry of Sintered Oxide Ca0.9La0.1MnO3 ‐ δ and Its Cathodic Properties in Alkaline Solutions

The nonstoichiometry (3‐δ) of perovskite‐type oxide was detected by thermal gravimetric analysis (TGA) to be 2.97 at room temperature in air, which means that 84% of the manganese was tetravalent. The electrical conductivity of sintered porous oxide (porosity: ca. 60%) prepared as the active material was at room temperature, which was high enough to use it as a conductive cathode material. The sintered ceramic behaved as the cathode material with no conductive powder such as graphite in alkaline solutions. The discharge capacity depended on the concentration and the kind of alkali and was largest in 5% LiOH solution , indicating that manganese in the oxide was reduced partly from to . This discharge capacity was almost comparable to that of electrolytic if one includes the necessary conductive material (such as graphite) in the latter case.

Crosslinking of Cotton Fabrics Premercerized with Different Alkalis

We studied the properties of cotton fabric samples premercerized with three kinds of alkalis and crosslinked with varying DMDHEU concentrations in the finishing bath. At a given nitrogen content and number of crosslinks, the change in wet crease recovery angle of finished fabrics from various premercerizing solutions ranked in the order of LiOH mercerized fabric > NaOH mercerized fabric > KOH mercerized fabric > unmercerized fabric. However, changes in tensile strength and elongation of the finished fabrics for the various premercerized samples are ranked as KOH mer cerized fabric > NaOH mercerized fabric > LiOH mercerized fabric > unmercerized fabric for a given nitrogen content and number of crosslinks. The value of crosslink length for the various finished fabrics has the same order at a given number of crosslinks. Degrees of surface migration of the agent on the finished fabric surface with NaOH and KOH premercerizing are significant.

Kinetics of Electroless Copper Plating and Mechanical Properties of Deposits

Electroless copper films were prepared from an EDTA bath in which pH was adjusted with three kinds of alkalis (, , and ). Mechanical properties of the deposits and the kinetics of electroless copper plating were investigated to clarify their mutual relationship. The use of , among the alkalis tested, gave the best result for the mechanical properties. The electrochemical analysis of the electroless copper deposition based on the mixed potential theory indicates that there is an interaction between the partial anodic and cathodic reactions, which is induced by the adsorption of methylene glycol anion. The polarization technique using a quartz crystal microbalance electrode and the AC impedance method disclose that an improvement of the mechanical properties of copper films is achieved when such an interaction is eliminated by preventing the adsorption of methylene glycol anion through utilizing and surfactant such as polyethylene glycol as well as elevating the bath temperature.

Hydrogen absorption in palladium electrodes in alkaline solutions

The entry of hydrogen into a palladium electrode in alkaline solutions was investigated. It is shown, from analysis of the overpotential components observed in transient polarization measurements, that the hydrogen electrode reaction on palladium obeys the Volmer-Tafel mechanism, similar to that in acidic solutions studied earlier. Hydrogen pressures equivalent to hydrogen overpotentials are evaluated. They increase with the overpotential but the dependence is much less than that calculated by applying a Nernst type equation to the total overpotential; this is also similar to the behaviour observed in acidic solution. The equivalent hydrogen pressure is practically independent of the concentration of alkali but slightly dependent on the kind of alkali, being highest in KOH solution.

Fatigue limit and crack arrest in alkali-containing silicate glasses

Crack growth, including fatigue limit and crack arrest, have been investigated for glasses of the systemsxNa2O-11Al2O3-(89-x)SiO2,xNa2O-(100-x)SiO2 andxNa2O-7CaO-(93−x)SiO2 in water as well as in acid and alkaline solutions. From studies of the dependence of the crack arrest on the alkali content of the glass, the kind of alkali (K+, Na+, Li+), the pH of the corrosive medium, the ageing time and ageing loading in conjunction with measuring the alkali leaching behaviour, the basic mechanism of crack arrest and fatigue limit can be concluded. Owing to load- and medium-dependent diffusion processes, a crack-growth retarding leached layer at the crack is generated with modified strength and crack growth properties compared to the bulk properties. In high alkali-containing glasses the process is additionally stimulated by stresses produced in the leached layer at the crack tip and at the crack surfaces.

RHEOLOGICAL BEHAVIOUR OF AQUEOUS SYSTEMS CONTAINING POLYOXYETHYLENE FATTY ALCOHOLS WITH DIFFERENT HLB

ABSTRACT In this paper the influence of several factors on the rheological behaviour of aqueous systems containing 0.25 and 0.50 mol(L of a polyoxyethylene fatty alcohol has been analysed. Such factors are: temperature, pH, kind of alkali used to increase the pH and HLB of the surfactant. The influence on the rheological parameters when samples are introduced into the sensor systems either as liquids or as liquid crystals has also been studied. The experimental results have shown that the studied systems present Newtonian, pseudoplastic or plastic-pseudoplastic rheological behaviour at steady state shear. A photomicrographic study for systems having a plastic-pseudoplastic behaviour was carried out in order to find out if lyotropic mesophases were present. The results are discussed in relation to the effects that the above mentioned factors exert on the shape and size of the aggregates

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Quantitative Analysis for Ion-Exchanged Glass Containing Three Kinds of Alkalis by Elbctron Microprobe

Quantitative Analysis for Ion-Exchanged Glass Containing Three Kinds of Alkalis by Elbctron Microprobe

Influence of alkali on the carbonization process—III: Dependence on type of alkali and of alkali earth compounds

3,5-Dimethylphenol-formaldehyde resin was carbonized up to 1000°C with various kinds of alkali and alkali earth compounds added. The hydroxides of Li, Na, K, Sr and Ba reacted with the resin to produce large amounts of hydrogen and CO. The order of reactivity was, Li < K < Na and Ca, Mg ⪡ Sr < Ba. Carbonates evolve only a small amount of hydrogen, although evolution of CO was very large. Carbonates cannot react with reactive methylene groups or aromatic hydrogens, whereas hydroxides easily substitute these hydrogens with MO-, liberating hydrogen atoms. The reduction of carbonate with carbon takes place in a similar way as that with hydroxides. The lower the melting point of the alkali or alkali earth compounds is, the lower the temperature of evolution of hydrogen is. This may be due to the good wettability of lower melting alkali or alkali earth compounds.

Creation of reactive centers on cotton. II

Acrylamidomethylated cellulose (AMC) was prepared by reacting cellulose with N-methylolacrylamide or its ethers in acidic medium under a variety of conditions. The extent of the reaction, expressed as mmole double bonds per 1 g cellulose, increased by increasing the concentration of N-methylolacrylamide or its ethers. However, the paddry-cure technique produced AMC with greater amounts of double bonds than the pad-batch technique. Also, the reactivity of the etherifying agents follow the order N-methylolacrylamide>N-methoxymethylacrylamide>N-methoxymethylmethacrylamide. Furthermore, the behavior of AMC in neutral, alkaline, and acidic media was studied. No change in the amount of the pendent double bonds of AMC occurred in neutral medium regardless of the conditions employed. On the contrary, disappearance of the double bonds took place in alkaline medium. The extent of disappearance depends on the kind of alkali used as well as on the conditions implemented. It was disclosed that consumption of the pendent double bonds of AMC occurred mainly via addition of the cellulose hydroxyls to yield a crosslinked cellulose. Treatment with hydrochloric acid, on the other hand, resulted in partial splitting of the acrylamidomethyl groups as well as addition of the acid on the pendent double bonds of AMC.

Effect of Glass Composition on the Reaction of Mixed-Alkali Lead Silicate Glasses with Molten Lithium Nitrate

The ion-exchange reactions of mixed-alkali lead silicate glasses with molten lithium nitrate were carried out for 1 to 5 hours at 380°C.The results obtained are summarized as follows:(1) In the ion-exchange reaction of a mixed-alkali glass containing two different kinds of alkalis, the diffusion of one type of alkali ion occurs independently of the other.(2) For the mixed-alkali glasses containing Na2O and K2O, the amount exchanged becomes minimum at the molar concentration ratio (βK) of about 0.5.(3) For the simple alkali glasses containing Na2O or K2O, the amount exchanged decreases remarkably with increasing PbO content. But, for the mixed-alkali glasses, it varies very little with PbO content.

Viscosity of Molten Glass of Mixed-Alkali Lead Silicate

The viscosity of melts in the system R2O (R=Na, K, Li+Na, Na+K, K+Li, and Li+Na+K)-PbO-SiO2 was measured by the platinum ball pulling-up method at temperatures ranging from 1000° to 1400°C.The results obtained are summarized as follows:(1) In connection with the fact that the glass contains a small amount of alkali it is found that, on the molar basis. the potash glass is more viscous than the soda glass.(2) The effect on the material that is charged with alkali is observable in the Li-K glass containing two different kinds of alkalis i.e., Li2O and K2O.(3) In the Li-Na-K glass containing constant quantity of 2.5mol. %Li2O or K2O, the minimum of viscosity is observable at the molar concentration ratio (βk and βNa) of about 0.33. But, in the glass containing constant quantity of 2.5mol. %Na2O, it is observable at molar concentration ratio (βLi) of about 0.5.(4) The same tendency of composition and the correlation between the viscosity and the apparent activation energy of viscous flow is also observable.

Self‐detergence of raw wool. I. ‘Suint scouring’

AbstractThe degree of partial detergence accomplished by passing representative subsamples of several lots of greasy wools at controlled alkaline pH values (generally constant in each experiment) through the same bath of water at 50°c has been followed by estimations of loss of grease as well as loss of all soiling materials. The degree of detergence usually tends to rise to a maximum and then often falls off as is usual when detergent concentration is increased in other systems. As the pH of the detergence is raised, the maximum attained rises and the fall‐off generally occurs earlier, at least up to pH 10.0. The course of detergence varies with the kind of alkali and its purity. Inorganic salts and amyl alcohol raise the maximum and increase the rate of fall‐off of the self‐detergence. Other methods of raising the degree of detergence are explored. The maintenance of maximum detergence for all wools is a complex problem.

Absorption Characteristics of the Phosphate Glasses Containing Ferrous Iron Introduced as the Near Infra-red Absorbent

Preparation of alumino-phosphate glasses containing a few per cent of FeO, which are used as the infra-red shielding glass, are fairly difficult because their light absorption spectrum is liable to be affected delicately by their chemical compositions even when they are prepared under the same melting condition. The author has made a study on the effects of chemical composition on the light absorption characteristics of this type of glasses.Glasses of the two system, P2O5-Al2O3-ZnO-R2O and P2O5-Al2O3-B2O3-R2O, both containing FeO as the infra-red absorbent, were melted under the reducing condition given by the addition of metallic silicon. For the glasses prepared the absorption measurement was made in the range 0.4 to 2.2μ.For these glasses two strong absorption bands were almost always observed at about 1.1 and 2.2μ in their absorption spectrum. The glasses containing FeO more than 3.2 mole per cent and R2O less than 5 mole per cent were found to have a satisfactory infrared shielding power. With increasing the alkali (R2O) content the infra-red absorption of glass decreased, becomming liable to be affected by the kind of alkali. When the R2O content reached to 14 mole per cent, with the exception of lithia, the glasses were stained with brown color, showing the anomalous absorption at the shortwave region. The infrared absorption of the glass containing B2O3 was little stronger than that of the glass containing ZnO.The relation between the state of iron in the phosphate glasses and the absorption characteristics was explained by the screening theory proposed by W. A. Weyl.