Materials Literature
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Sixty‐six years have passes since rhenium was discovered in June 1925 by husband‐and‐wife team Walter and Ida Noddack. The rapid development of rhenium is due to the unique properties of the metal and its alloys. Rhenium has a hexagonal close packed structure as opposed to the body centered cubic structure of other re…
The effects of different relative humidities on some physical properties of three types of calfskin parchment (vellum) were investigated. Standard samples were subjected to (1) tensile fracture, and (2) measurement of the force that developed when the restrained samples were subjected to step decreases in relative hum…
The absorption coefficient values of several silicate glasses in the IR radiation range were determined. Four methods were employed in this study: (1) direct transmission by CO 2 laser, (2) direct transmission through ultrathin sections using an IR spectrometer, (3) glass particle dispersions in KBr pressed pellets, a…
At low earth orbit (LEO) altitudes of 100–1000 km, pressures are relatively high (10−5 Pa) and the residual atmosphere consists primarily of atomic oxygen (AO). Spacecraft orbital velocities, approximately 8 km/sec, at LEO altitudes result in a reactive chemical environment with 5eV AO. Long-term (10–30 years) operati…
Transfer of a sulfur atom from S2Cl2 to cis-[TcN(Cl)(phen)2]PF6(phen = 1,10-phenanthroline) yields cis-[Tc(NS)Cl(phen)2]PF6, which crystallizes in the triclinic space group, P(no. 2), with cell parameters a= 9.850(3), b= 16.293(3), c= 8.349(2)Å, α= 100.06(2), β= 93.84(3) and γ= 106.96(3)°. The Tc–NS bond length is 1.7…
Abstract CaF 2 ‐crystals belong to the standard materials, used in optical precision instruments. As well as the traditional optics for microscopy new developments in the field of DUV‐lithography (projecting lenses made out of CaF 2 and quartz) need a homogeneity of the refractive index in the order of 10 −6 , but ove…
Titanium-polymethacrylate composite was prepared as an x-ray-opaque filler for composite core materials. The base monomers of the composite were 2,2-bis [4-(3-methacryloyloxy-2-hydroxypropoxy) phenyl] propane (Bis-GMA) and triethyleneglycol dimethacrylate (TEGDMA). Pure titanium powder was used as a radiopaque element…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTemperature- and axial-ligand-dependent EPR spectra of cobalt porphyrin cation radicals: effects of mixing of the A1u and A2u states and a locally excited triplet stateSatoh Minoru, Yasunori Ohba, Seigo Yamauchi, and Masamoto IwaizumiCite this: Inorg. Chem. 1992, 31, 2, 298–…
The major source of shutdown radiation in PWR plant is the 60 Co radio nuclide generated from Stellite alloys used for wear resistance in the circuit. Initial attempts to replace cobalt based alloys with materials based on the nickel-chromium-boron system were unsuccessful in prototype testing. A galling test applied…
A number of compounds of the chemical formula [(C2H5)4N]2MX4 exhibit structural phase transitions in the temperature range 200–300 K, which were found in calorimetric investigations. Dielectric measurements on pellet samples confirmed the existence of the phase transitions and ferroelectricity in [(C2H5)4N]2 MnCl4 has…
The morphology and mineralogy of corrosion products found on copper and silver artifacts recovered from shallow land or water burial are reviewed. Stability diagrams are used to interpret mechanisms for corrosion phenomena with an emphasis on identification of microbiological action.
The discovery of heavy metal fluoride glasses has opened new prospects for fiber optics operating beyond 2 µm with expected losses less than 10(-2) dB/Km. The main interest of fluoride glasses lies in their infrared transmission up to 8 µm in the bulk form and 4.5 µm for optical fibers. We have reported here the prepa…
Abstract Acid‐catalysed condensation polymerization of 1,6‐hexanediol, 1,8‐octanediol and 1,10‐decanediol was carried out in the 150–190°C temperature range in the presence of sulphuric acid or Nafion‐H resin, and the polymerizations were monitored by size‐exclusion chromatography. The products were identified as hydr…
Investigations of ω phases formed by isothermal aging in Ti–20 wt-%Mo alloy and by deforming in tension in Ti–14 wt-% Mo alloy were carried out using transmission electron microscopy (TEM). Four ω phase variants in the same region of Ti–20Mo alloy single crystal aged at 623 K for 28·8 ks were observed using dark field…
The use of surface coatings, which are applied to the hot-end components of the modern gas turbine to protect against oxidation and/or corrosion, is commonplace and the correct choice of coating process is a balance between cost effectiveness, operational environment and lifetime. This paper reviews a broad range of c…
In situ neutron reflectivity measurements on potentiodynamically deposited polybithiophene (PBT) films on Pd electrodes supported on quartz are described. The contrast-variation method allows determination of polymer film structure with high resolution perpendicular to the electrode surface. Both undoped and p-doped P…
The paper describes digital-processing techniques for determining the pore-size distribution in a fabric. A magnified image of a sample of fabric is captured by a video camera, and the image is processed to determine pore-size distributions according to three definitions. The sizes of the pores in a fabric to be used…
We report on measurements of the specific heat and thermal diffusivity of Pyrex 7740 glass for temperatures between 20 and 310 K. The thermal conductivity was determined from the measured quantities. Our results are compared with theoretical predictions for glasses.
Abstract A polycyclic Terra Rossa (Chromic Cambisol on Rhodic Nitisol) was studied with the aim of characterizing pedogenetic processes and relating the most evolved term of a previously defined catena with its parent material. Results obtained by field, chemical, micromorphological, sedimentological and mineralogical…
If a wool fabric is restrained during drying, as in tentering, there is a close relationship between the relaxation shrinkage that is induced and the hygral expansion. A high correlation also exists between the hygral expansion and extensibility of relaxed fabrics. For conventional woven fabrics, this relationship is…