Materials Literature
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In the course of examining new electrode systems for anodic oxidations, the carbon paste electrode was developed. This electrode has proven far more valuable than originally expected and it is the purpose of this paper to critically review its properties, applications, and shortcomings. It is fitting that emphasis be…
Abstract The influence of crystal surface orientation on the graphitization of diamonds heated in vacuum to temperatures about 1700 °C has been studied. It was found that the rate of graphitization is highest in the 〈110〉 directions and lowest in the 〈001〉 directions.
The oxidation of graphite is an interesting reaction due to its technological importance. Volatile reaction products of carbon monoxide and carbon dioxide are formed at all temperatures above 25°C. Below 800°C a small amount of surface oxide is also formed. The rate of oxidation below 800°C is limited by a chemical pr…
The oxidation behavior of tantalum has been studied at 700°–1000°C at oxygen pressures ranging from 1 atm to 0.01 Torr O 2 . The oxidation involves oxide formation and oxygen dissolution in the metal. The rate of oxygen dissolution is governed by diffusion of oxygen in the tantalum metal. Except for the very initial s…
In aqueous solutions of the corrosion of Al can be accelerated by chemical promoters such as S = (or SH − ) ions and/or by a thermal runaway mechanism, and inhibited by surface amalgamation, especially with ‐saturated solutions, and/or by alkyldimethylbenzylammonium salts. Corrosion is also markedly reduced at high an…
Abstract The dissolution process for sintered uranium dioxide into nitric acid falls into two regimes of behaviour which depend on the overall transfer rate. The critical dissolution rate is approximately 8 mg. cm. −2 min −1 , its precise value depending upon the solvent composition. Below this critical value there is…
The thermal conductivities of relatively large homogeneous samples of and have been measured in a dynamic calorimeter from 0°C to 300°C. In both samples, phonon scattering predominates, and the relationship, was observed. For , and for
A theoretica study is made of damage effects by particle radiations in mater, and their dependence on energy, mass,, and charge number of an incoming particle, as well as on the composition of the medium. Typical examples of damage effects are the number of ion pairs formed in a gas, or the number of vacancies created…
A study of the oxidation of boron carbide powder has shown measurable reaction at temperatures as low as 250 °C with water vapor and 450 °C in dry air. Removal of the B 2 O 3 oxidation product by water vapor occurs at a rate in excess of the oxidation rate below 550°–600°C. The presence of B 2 O 3 on the B 4 C surface…
Furan resins were prepared by the polymerization of furfuryl alcohol with either acid or thermal catalysis. The effect of catalysts, solvents, polymerization time, and atmosphere were studied for their effects upon the chemical structure of the polymer produced. It has been found that, regardless of the technique empl…
The concept of a thermo-photo-voltaic (TPV) energy converter is introduced and the device compared with thermoelectric and thermionic converters. Features of the TPV converter are that the entire device is kept at room temperature; potential power densities on the order of 10 w/cm2, and potential conversion efficienci…
A large number of polycrystalline and amorphous materials ranging from pure metals to glassy polymers have been found to obey the relations α2E=150 [dyn cm−2°K−2]s at normal temperatures. The linear coefficient of expansion is denoted by α, Young's modulus by E, and s is a dimensionless spread factor (0.5<s&…
The effects of method of equilibration, soil-water ratio, pH, and temperature on the form and concentration of dissolved silica in soil-water mixtures were studied and some hypotheses concerning the role of soluble silica in soil development were evaluated in the light of the information obtained.Studies of methods of…
The effect of lithium addition on the flow stresses for basal and nonbasal slip in magnesium crystals has been investigated by tensile tests at various elevated temperatures, using Mg-Li alloy single crystals of h.c.p. structure. The critical resolved shear stress for basal slip is found to increase almost linearly wi…
The planar stress-strain relationships of a simple trellis in which the elements are pivoted together where they cross over one another, but which do not pass under and over one another, are presented. It is shown that these relationships are identical with those tor an anisotropic elastic lamina which does not displa…
Abstract Durch eine Reihe von neuen Strukturbestimmungen ist es möglich geworden, eine Systematik für die Rauminkremente und die Radien von negativ geladenen Ionen aufzustellen. 1. Die Rauminkremente sind in Reihen wie Ge − , As − , Se − , Br − praktisch konstant. Ein Vergleich mit den Atomvolumina ergibt, daß das Hin…
The inhibiting effect of pyridine and seven of its methyl derivatives on the corrosion of iron in O 2 ‐free, 6.08 N HCl at 35°C was determined. Corrosion rates were measured by colorimetric analysis for iron with mercaptoacetic acid. The relative inhibitor efficiency and cathodic potential shift increased with increas…
Thin organic polymer film specimens were prepared for electrical conductivity measurements by the glow discharge polymerization process. The experimental procedure for film preparation is described in detail. Data on film properties and deposition efficiencies (g/kwhr) are presented for their possible bearing on the p…
Abstract Melting temperature, enthalpy and entropy of a sample of highly isotactic polybutene‐1 in each of the three polymorphic modifications as yet recognized, are determined by the method of the depression of the melting point in the presence of diluents. Two diluents are chosen: α‐chloronaphthalene and decalin, as…
The voltage required to maintain local discharges on polluted insulation may increase with increase in discharge length, and if this voltage exceeds the supply voltage, the discharges extinguish without causing a flashover. An analysis based on this mechanism has been made for the simplified case of an insulator havin…