Materials Literature
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Abstract A mechanism for the degradation of polymer molecules in ultrasonic cavitation has been proposed which takes into account the energy released by imploding cavitation bubbles in the form of hydrodynamic waves. Relationships for degradation rate constant and limiting chain length linking with the cavitation ener…
The levitation forces on metal spheres in magnetic fields of axial symmetry are derived theoretically. Criteria for stability of the center of mass are obtained. It is shown for nonmagnetic samples that the desirable coil configurations are those which provide a constant field gradient along the symmetry axis. The for…
Abstract Depending on the method of preparation ,,NiO”-single crystals of different colours can be synthesized. It is shown by ligand field spectroscopy that the ligand field and interelectronic repulsion parameters are the same for the green, yellow and brown crystals. There is definite spectroscopic evidence, that t…
Abstract The influence of sodium chloride on the atmospheric corrosion of mild steel has been studied. Samples covered with sodium chloride crystals (8 m̈g NaCl · cm −2 ) have been exposed to an SO 2 ‐free atmosphere at different relative humidities. The combined effect of sodium chloride crystals on a steel surface a…
The magnetisation and Mossbauer effect have been measured for the Invar type FCC Fe-Pt alloys. The atomic moment of the alloys varies linearly with concentration, following the Slater-Pauling curve, which indicates that the iron atom possesses a full moment of 2.7 mu B even in the Invar region. The hyperfine field act…
The method and results of high speed streak photography of surface flashover in vacuum are presented. It is shown that the bright phase of the flashover arc bridges a 12.5 mm gap in 0.15 ns. The streak records indicate that the flashover arc is preceded by an intense electron burst from the cathode-insulator junction.
General formulas are derived for the estimation of fiber orientation and distribution in fiber assemblies whose constituent fibers are arbitrarily crimped. It is found that the density function of orientation can be estimated by solving an integral equation which relates it to the average numbers of fiber cross sectio…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTExperimental evidence for trapped valences in the mixed-valence complex .mu.-pyrazine-bis(pentaammineruthenium) tosylate. Electron paramagnetic resonance, magnetic susceptibility, and nuclear magnetic resonance resultsBruce C. Bunker, Russell S. Drago, David N. Hendrickson,…
Cross-linked polyethylene, now commonly used for insulation of underground electric distribution cables, is susceptible to electrochemical treeing, in common with other polymeric dielectrics. This treeing phenomenon sometimes originates at holes or cavities present in the cable. A polishing and etching technique has b…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTIntramolecular antiferromagnetic exchange in tris(o-semiquinone) complexes of vanadium(III), chromium(III), and iron(III)Robert M. Buchanan, Hartley H. Downs, William B. Shorthill, Cortlandt G. Pierpont, Stephen L. Kessel, and David N. HendricksonCite this: J. Am. Chem. Soc.…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTJahn-Teller effect in the 4T2g state of chromium(III) in dicesium sodium indium(III) hexachlorideHans U. Guedel and Timothy R. SnellgroveCite this: Inorg. Chem. 1978, 17, 6, 1617–1620Publication Date (Print):June 1, 1978Publication History Published online1 May 2002Published…
The oxidation of NO toNO2 and CO to CO2 in quartz gas-sampling microprobes drawing gases from fuel-lean flames of CH4/air and CO/air has been modeled and measured. The kinetic model includes surface recombination of O- and H-atoms. Confirming measurements were obtained by gas-sampling a jet-stirred reactor. It was pre…
The index of refraction of oxides grown on silicon in dry oxygen has been found to be a function of the growth temperature. There is an orientation effect for oxides grown at low temperatures. The index decreases with temperature, saturating above 1190°C at 1.4620, a value consistent with the index of fused quartz whe…
Chicken gizzard filamin has been digested with purified Ca2+-activated protease. The subunits of (Mr = 250,000) of the protein are cleaved asymmetrically into two fragments, heavy merofilamin, Mr = 240,000, and light merofilamin, Mr = 9,500. Digestion is complete at substrate to enzyme ratios of 100:1 and requires Ca2…
The physical and nuclear properties of EU2O3 were reviewed, evaluated, and compared with those of the other potential control materials for breeder reactors. Europia with a 90% theoretical density has approximately the same amount of europium atoms per unit volume as the pure metal. Consequently, the reactivity worth…
A new Sn II O compound , the first oxostannate( II ) of defined structure, has been obtained as brownish‐yellow single crystals. X‐Ray structure analysis reveals a complicated perovskite variant (Sn 1 O 3 Sn 2 double layers) in which half of the anions are missing in a regular manner.
Polybenzimidazole (PBI) is the only textile fiber, either commercial or developmental, which under normal conditions is nonflammable in air, emits little or no smoke, and produces virtually no toxic offgases up to a temperature of 560°C. PBI also has the textile processing properties of polyester, and garments made fr…
Abstract A new EPR spectrum of V 2 O 5 is reported which is related to the non‐stoichiometry of the crystals. Its intensity increases on reduction and decreases on reoxidation. The spectrum is labelled El. El can be described by an S = 1 spin Hamiltonian with parameters g x = 1.33, g y = 2.51, g z = 1.01 ( y ‖ b , x a…
Summary The high-temperature transformation of andalusite (Al 2 SiO 5 ) into 3/2-mullite ( 3 A 2 O 3 2SiO 2 ) plus vitreous silica (SiO 2 ) has been studied within the temperature interval from 1300 to 1600 °C by means of X-ray powder and single-crystal techniques and by infrared spectroscopy. Results are interpreted…
The well known breakdown theories, Townsend's generation mechanism and the streamer mechanism, are reviewed and applied to the results of breakdown in the strongly electronegative gas, sulphur-hexafluoride. Experimental results reported in the literature on the breakdown behavior of sulphur-hexafluoride are examined i…