Attraction of nematodes to metabolites of yeasts and fungi

The free-living nematodesPanagrellus redivivus andRhabditis oxycerca are strongly attracted to methyl, ethyl, propyl, butyl, and amyl acetate, to ethyl, propyl, and amyl formate and to ethyl propionate, but all the respective alcohols and acids are without effect. No loss of attraction is observed when the attractants are combined with lethal concentrations of the commercial nematicide sodium methyl dithiocarbamate.     

Radiothermoluminescence curves of polymeric materials in the region of releasing frozen molecular motions

Summary The glass transition peak of radiothermoluminescence (RTL) curves in a statistical butadiene — styrene copolymer shows a distinct dependence on the cooling rate prior to irradiation. The higher the cooling rate, the lower the intensity and the temperature of the RTL glow curve maximum. These experimental findings are in accordance with a recently proposed theory of RTL in terms of glass transition phenomenology.     

Studies of the deposition of cadmium on foreign substrates

Cadmium deposition on nickel, lead, silver, gold and copper has been studied by the potential sweep and potentiostatic method with a simultaneous observation of the surface by optical microscopy. It was found that the substrates could be divided into two groups—those at which there is no significant underpotential deposition of cadmium and those at which the latter does take place. In the former case non-epitaxial growth predominates, once some nucleation overpotential (of about 16 mV) is overcome; the potential sweep diagrams are characterized by a loop exhibiting an inductive nature. Two maxima on the anodic branch of the voltammogram could be ascribed to the dissolution of non-epitaxial and epitaxial deposits. Microscopic observations confirmed those conclusions. Well developed granular deposits have been obtained with grains increasing size while remaining constant in number.     

Kinetics and mechanism of deposition of zinc from zincate in concentrated alkali hydroxide solutions

Galvanostatic investigation has been carried out of the kinetics of the reaction on zinc amalgam hanging mercury drop immersed in alkaline zincate solutions at KOH concentrations ranging from 1 to 14 normal. Three kinds of data have been extracted: (i) the pseudo-capacitance as a function of overpotential from the portion of the charging curves prior to plateaux, (ii) the Tafel plots from quasi-steady state values at the plateaux and (iii) the Sand's products as function of current density from transition times. In (i), the pseudo-capacitance was found to increase with overpotential, in (ii), two slopes (60 mV dec^?1 and 120 mV dec^?1) have been found in the cathodic direction and a limiting current in the anodic one; in (iii), the Sand's product was found to decrease with increasing (i). On the basis of the above findings the reaction mechanism has been suggested to be of the cece type, with the chemical dissociation of the intermediate univalent zinc complex in between the two elctrochemical steps as rate-determining. A modification of the method of evaluating the reaction orders was introduced to account for a simultaneous change of more than one activity of reactants in concentrated solutions. Using this, reaction order was found to be 2 with respect to both OH^? ions and water, suggesting that the electroactive species is not only reduced in the number of ligands but also dehydrated with respect to the prevailing species. The anodic limiting current appears to be due to the accumulation of Zn(OH) species to cover all the surface free of adsorbed Zn(OH)₂. Exchange cd and rate constants of all the four steps of the reaction have been estimated.     

Potential of proton-enhanced 13C n.m.r. for the classification of kerogens

High resolution n.m.r. spectroscopy, involving the technique of cross-polarization, along with magicangle spinning, was used in the structural characterization of eight kerogens of different origins, selected to represent the three types of kerogens (types I–III evolution paths). The influence of cross-polarization dynamics on the sensitivity of the method and the ratio of individual fractions in the spectrum was studied in more detail. It is suggested that an analysis of the influence of the mixing time is necessary prior to definitive characterization of any sample. Good separation of signals in aliphatic, aromatic, and carboxylic regions was achieved. The general correlation between the ¹³C n.m.r. structural characteristics and the classification based on ultimate analysis of the kerogens (types I–III, van Krevelen atomic H/C vs. O/C diagrams) was found to be satisfactory. The structural features of kerogens derived from ¹³C n.m.r. analysis agreed quite well with characteristics constituting the above mentioned classification. The ¹³C n.m.r. method used in this paper may be considered promising in the classification of kerogens.     

The effect of Cl(I)− ions on kinetics and mechanism of anodic dissolution and cathodic deposition of copper

The influence of Cl(I)^? ions on kinetics and mechanism of anodic dissolution and cathodic deposition of copper in acidic sulfate was investigated. For this investigation the galvanostatic single-pulse method has been used. The results indicate that Cl(I)^? ions change the exchange current density and transfer coefficients as determined from tafel analyses of the anodic and cathodic reactions.     

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.