Showing papers on "Nickel published in 1974"

Studies on the gorwth of Thiobacillus ferrooxidans. 3. Influence of uranium, other metal ions and 2:4-dinitrophenol on ferrous iron oxidation and carbon dioxide fixation by cell suspensions.

Abstract: Suspensions ofThiobacillus ferrooxidans in Warburg flasks oxidized ferrous iron and coupled14CO2 fixation to the oxidation. The sulphates of zinc, cobalt, copper, nickel or uranium (0.1–1.0 M) depressed the rate of Fe2+ oxidation: nickel and uranyl ions were the most inhibitory. Uranyl, copper and nickel ions inhibited iron-dependent CO2-fixation, the two former producing a marked uncoupling effect on CO2-fixation, similar to that produced by 2:4-dinitrophenol. Molybdate also inhibited iron oxidation. Incorporation of14C-labelled amino acids and glucose was largely dependent on energy from ferrous-iron oxidation and was also strongly inhibited by uranyl sulphate. Kinetic analysis of the inhibition of iron-oxidation by uranium indicated mixed competitive and non-competitive inhibition. Little binding of238U,63Ni or59Fe toT. ferrooxidans was observed and the effects of uranium were concluded to result mainly from loose binding at sites on the cell membrane concerned with iron-oxidation and possibly the transport of other metals. Molybdate probably interfered with sulphate-dependent steps of iron oxidation. Uncoupling of CO2-fixation probably resulted in part from interference with energy metabolism and could depend on transport of uranyl ions through the cell membrane. CO2-fixation by an uraniumtolerant culture (U+) was less sensitive to uranyl-inhibition than that by the wild-type strain (U−), but iron oxidation and CO2-fixation were much more sensitive to uranium when the U− organisms were previously cultured on thiosulphate rather than ferrous iron.

Nickel in plant growth and metabolism

Abstract: The relationship of nickel to plants in regard to absorption, translocation and accumulation and its estimation in plant material has been presented. Nickel is usually absorbed in the ionic form, but is presumably chelated by organic carriers before translocation takes place. Nickel content of various plants has been tabulated. Nickel stimulates, and is as well toxic to, the germination of some seeds. It regulates the mineral metabolism, enzyme activity and several other metabolic processes in plants. It causes mitotic disturbances in root tips of some plants. Nickel salts are the best systemic fungicides. It is used as a fungicide mainly for the control of cereal rusts both because of its protective and eradicative properties. At the nonphytotoxic levels, nickel increases the yield of some crops. High concentrations of nickel cause severe chlorosis and necrosis in plants and a host of other growth abnormalities and anatomical changes. Nickel is not absolutely required for the normal growth and development of plants and, therefore, can not be ranked under the “essential elements”. Nevertheless, it is necessary for the healthy development of some plants (e.g.,Alyssum sp.) where it is considered as an “essential element”.

Catalyst for electroless deposition of metals

Abstract: A solvent method for the metallization of a non-conductive surface with gold, nickel or copper is shown whereby on a substrate a thermosensitive coordination complex of palladium is deposited; the complex has the formula LmPdXn wherein L is a ligand or unsaturated organic radical, X is a halide, alkyl group or a bidentate ligand and m is an integer from 1 to 4 and n is from 0 to 3; trimethyl phosphite palladium dichloride complex is an appropriate illustration of the complex; the palladium complex is applied on the substrate in a suitable non-aqueous solution such as tetrahydrofuran solution; the complex is then baked in air at elevated temperature; the exposure to high temperature decomposes the complex leaving a residue which is catalytic to the deposition of gold, nickel, cobalt or copper from an electroless bath thereof; the non-conductive material is then immersed in an electroless bath to metallize the areas which have been rendered catalytic; the preferred thermosensitive coordination complex of palladium is trimethyl phosphite palladium dichloride; a requirement for a proper thermal exposure of the complex is that the substrate is capable of withstanding the elevated temperatures such as above 210°C; illustrative organic substrates are polyimides, polysulfones, silicones, vulcanizates, fluoroplastics, polyphenylene sulfides, polyparabanic acids, and polyhydantoin, etc.

Crystallographic Dependence of Chemisorption Bonding for Sulfur on (001), (110), and (111) Nickel

Abstract: The degree to which the surface atomic arrangement influences the bonding geometry of sulfur atoms on (001), (110), and (111) Ni surfaces is investigated by an analysis of experimental low-energy electron diffraction data. For all surfaces, the sulfur atoms reside in high-coordination sites---the atomic hollows of the surface; all nearest-neighbor Ni-S bond lengths are less than those of stable bulk compounds.

Electrocatalysis by metal phthalocyanines in the reduction of carbon dioxide

Abstract: It is shown that cobalt and nickel phthalocyanines are active catalysts for the electrode reduction of carbon dioxide.

The intergranular embrittlement of nickel by hydrogen: The effect of grain boundary segregation

Abstract: The mechanical behavior of polycrystalline nickel specimens that were deformed in tension and cathodically charged with hydrogen simultaneously was investigated with particular emphasis on the fracture of such electrodes. This procedure leads to definite, if, however, weak serrated yielding and also markedly reduces the elongation at fracture compared to polycrystals unexposed to hydrogen. Moreover, in contrast to hydrogenated nickel monocrystals which neck down to give a chisel-edge fracture typical of ductile metals, hydrogenated polycrystal fractures are brittle and intergranular. The embrittlement of nickel by hydrogen is shown by means of Auger electron spectroscopy to be associated with the segregation of hydrogen recombination poisons to the grain boundaries. In essence, it is suggested that the entry of hydrogen into the nickel specimens occurs preferentially in the proximity of grain boundary intersections with the free surface, due to the presence therein of Sb and Sn which act as hydrogen recombination poisons and stimulate the absorption of hydrogen by the metal. The presence of such impurities in the grain boundaries suggests that a pressure mechanism is not involved in the intergranular cracking.

Catalytic process for reducing nitrogen oxides to nitrogen

Abstract: A catalyst compositions for reducing nitrogen oxide comprising, as its chief ingredient, an intimate mixture of A. titanium (Ti) as component A, with B. at least one metal selected from the group consisting of molybdenum (Mo), tungsten (W), iron (Fe), vanadium (V), nickel (Ni), cobalt (Co), copper (Cu), chromium (Cr), and uranium (U), as component B, in the form of their oxides, and a process for reducing nitrogen oxides to nitrogen, which comprises contacting a gaseous mixture containing nitrogen oxides and molecular oxygen and a reducing gas with aforesaid catalyst compositions at an elevated temperature.

High temperature nicocraly coatings

Abstract: A highly ductile coating for the nickel- and cobalt-base superalloys having long term elevated temperature oxidationerosion and sulfidation resistance and diffusional stability consists essentially of, by weight, 11-48% Co, 10-40% Cr, 9-15% Al, 0.1-1.0% reactive metal selected from the group consisting of yttrium, scandium, thorium, lanthanum and the other rare earth elements, balance essentially Ni, the nickel content being at least about 15%.