Structural effects in electrocatalysis: oxidation of formaldehyde on gold and platinum single crystal electrodes in alkaline solution

The oxidation of formaldehyde in sodium hydroxide solution has been studied on platinum and gold single crystal electrodes with the (111), (110) and (100) orientations. There is apparently no structural sensitivity of this reaction, since minor differences have been found between the three low index faces. This is valid for both platinum and gold electrodes. The hydrogen adsorption on platinum and the AuOH formation on gold electrodes exhibit structural sensitivity in the same solution. Similar activity of platinum and gold electrodes is noteworthy. A weak adsorption of gem-diol, formed in the interaction of formaldehyde with H₂O or OH^? appears as the origin of the structural insensitivity of this reaction.     

Materials balance in primary batteries. II. Lithium inorganic batteries at high discharge rates

A study was continued of the design characteristics and optimization procedures leading to an improvement of the maximum cell capacity obtainable with the high power type lithium inorganic batteries. The general relations derived for the low power type cells have been modified for use in the design of the high power type cells. A materials balance was established for the interior components of cylindrical cells made for high discharge rates.Design parameters were calculated using a computer program for several sizes of cylindrical cells. A satisfactory agreement was reached between the predicted and the realized performance of the cells built with the calculated design parameters.     

Plastic bonded electrodes for nickel-cadmium accumulators II. Basic electrochemical parameters of the nickel oxide electrode

Plastic bonded nickel oxide electrodes, prepared at normal temperature by one-stage rolling onto a current collector of steel net or perforated sheet of a mixture of active mass used in pocket-type electrodes, a conducting component and a PTFE binder, were tested in alkaline electrolyte. At current loads of 3–100 mA/cm₂ the type of conducting admixture, the current collector and its surface treatment were found to have a pronounced influence on the current carrying capability of the electrode. The electrode performance, especially at 100 mA/cm² is dependent not only on the composition of the active layer but also on the quality (or nature) - but not degree of contact between it and the current collector.     

Alternating copolymerization of phenylvinyl sec-butyl ether and maleic anhydride

Summary The reactivity ratios k_1c/k_1c and k_2c/k₂₁ in the copolymerization of phenylvinyl sec-butyl ether (M₂) and maleic anhydride (M₁) were calculated by applying the generalized model described by Shirota and coworkers. It was found that under the experimental conditions applied in our work, the copolymerization proceeds predominantly through the participation of charge-transfer complex monomers.Dedicated to Prof. C.I. Simionescu in honor of this 60th birthday     

Some comments on models for evaluation of catalyst effectiveness factors in trickle-bed reactors

The result presented here illustrate that modified modulus, Λ, brings together the values for effectiveness factor for various particle shapes even f     

Effect of size and shape of catalyst microparticles on pellet pore structure and effectiveness

Catalyst pellets with bidisperse pore structure were simulated by packed bed of microporous ion exchange resin (sulfonated styrene-divinylbenzene copolymer) and inert glass particles. Inert particles of different size and shape were used to modify the shape and volume of transport macropores (voids between the particles).Tortuosities of pellets were obtained from the experimentally measured effect of internal diffusion on the rate of catalytic methanol dehydration.Analysis of results shows that in the region of strong internal diffusion influence the highest pellet effectiveness is achieved for equal-size spherical microparticles. To ensure optimum macropore structure even in the transition region between the kinetic region and the region of strong diffusion influence, volume of transport macropores has to be reduced by combination of appropriately-sized spherical catalyst microparticles.     

A model for mechanisms in plastic-encapsulated microelectronic devices during temperature-humidity tests—II

The model is considered in more detail than in Part I of the series, and is verified by results of laboratory tests on humidity absorption and plastication with respect to material analysis and degradation of bipolar transistors with respect to several electric characteristics of temperature-humidity bias. The results confirm the model very well. They allow derivation of methods to increase the reliability of microelectronic devices, and selection of tests and test conditions.