Materials Literature
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The corrosion rate and changes in the microstructure and fracture strength of alumina ceramics (93.0% Al 2 O 3 and 99.5% Al 2 O 3 ) were studied in 0.1 m to 25 m NaOH solutions at 150°C to 200°C, where m = mol/(kg of H 2 O). The attack of the caustic alkaline solution started at the grain boundaries. Consequently, the…
Data have been obtained for the rate of reaction of freshly generated iron surfaces at low potentials with aqueous solutions containing chloride ions. The presence of chloride ions accelerates the formation of the first monolayer of oxidized iron, but with no significant increase in the charge required to form it. The…
The fabric geometric models based on lamination analogy and stiffness averaging method are utilized to numerically characterize a 2-step braided composite. The model predictions were found to be in good agreement with results of mechanical tests performed in this study. The architecture of this material is investigate…
Individual bundles of ceramic fibers were infiltrated with SiC to study the reaction and diffusion kinetics during isothermal chemical vapor infiltration (CVI). More uniform infiltration was observed in samples where baffles were placed in the reactor and when HCl was added to the inlet gases. The evolution of the mic…
Abstract The crystal structure of fedotovite, K 2 Cu 3 O(SO 4 ) 3 has been determined, space group C 2/ c , a 19.037(6), b 9.479(2), c 14.231(5) Å, β 111.04(3)°, Z = 8, D x = 3.09 g/cm 3 . The main units of the fedotovite structure are formed around two additional oxygen atoms and consist of edge-sharing [OCu 4 ] tetr…
Using a viscometric assay and various electron microscopic procedures (negative staining, rotary shadowing, ultrathin sectioning) we have determined the influences of different kinds of ions and of ionic strength on the structures formed by assembly of soluble subunits of vimentin from bovine lens tissue or from Esche…
Two extreme textural types of cultivated surface soils are mainly considered here, non-shrinking red-brown earths and highly shrinking cracking clays. Total porosity is used to assess the structural status of the former. Values are compared with the highest and lowest values found in the field. For the latter, the cri…
The nematic-isotropic transition temperatures for aromatic calamitic compounds with terminal alkyl chains attached via a methylene group are usually found to be lower than those with an ether link. This difference is generally attributed to the higher anisotropy of the molecular polarizability expected for an ether li…
A disclination line or a shifting effect of the lens center had been observed in a homogeneously aligned or a hybrid-aligned liquid crystal microlens with an asymmetric electrode structure of a hole-patterned electrode and a plane electrode. These deteriorating factors of lens properties can be eliminated by a homogen…
Clay particle interaction as mediated by water is considered within the context of attractive and repulsive inter-particle forces-van der Waals forces, ion correlation forces responsible for the potential minimum between Ca-clay particles, cation hydration, ion induced structural forces and diffuse double layer forces…
The problem of obtaining asymptotic expressions describing the shape of small sessile and pendant drops is revisited. Both cases display boundary-layer behaviour and the method of matched asymptotic expansions is used to obtain solutions. These give good agreement when compared with numerical results. The sessile solu…
The intensity profile of the X-ray reflection from a crystalline material is related to the lattice disorder and the distribution of crystal sizes through its Fourier cosine coefficients. However, existing methods of obtaining these structural parameters from the coefficients require more than one order of reflection…
A process for surface modification of Al‐based materials is described which involves immersion in boiling Ce ( NO 3 ) 3 and CeCl 3 , followed by anodic polarization in a molybdate solution. Each of these three steps is carried out for 2 h. Al 6061 treated in this manner did not show any signs of uniform or localized c…
Copper phosphate glasses with 40, 50, and 60 mol% CuO in batch were melted in air at 1000°, 1100°, and 1200°C using quartz or alumina crucibles, and the [Cu 2+ ]/[Cu total ] ratio variations with melting time were measured. Glasses were oxidized during melting and reached equilibrium [Cu 2+ ]/[Cu total ] ratios which…
The isophlorins already discussed by Woodward in connection with chlorophyll synthesis are Janus-faced—on one hand porphyrins (N, N′-dihydroporphyrins) and on the other true annulenes ([20] annulenes not conforming to the Hückel rule)—and as such are structurally particularly interesting. Whereas isophlorins not subst…
Abstract Grain-size distribution, specific surface, thermal analysis, electron microscopy and X-ray diffraction were used to study the effect of dry grinding on the structure and properties of two kaolins of different degree of crystallinity. Grinding caused particles to fragment and resulted in the formation of stabl…
Glass‐ceramics containing barium–mica in the system Ba 0.5 Mg 3 (Si 3 AIO 10 )F 2 –2MgO · 2Al 2 O 3 · 5SiO 2 –Ca 3 (PO 4 ) 2 are two to three times stronger than conventional mica‐containing glass‐ceramics. Moreover, the barium‐mica glass‐ceramics are easier to machine, as confirmed by a drilling test using convention…
Abstract Surface‐enhanced Raman scattering of o ‐mercaptobenzoic acid (OMBA) in silver sol was investigated. At neutral and basic pH OMBA adsorbed dissociatively on the silver surface via both its sulphur and the carboxylate group and existed as sulphidobenzoate. As the sol solution was acidified, the carboxylate grou…
Following a major shortage of 99Mo in the 2009–2010 period, concern grew that the aging reactor production facilities needed to be replaced. Most producers were using highly enriched 235U (HEU) as the target material. The Organisation for Economic Co-...Read More
The use of decomposed methanol, i.e., hydrogen and carbon monoxide, in spark-ignition engines is reviewed. The emphasis is on onboard decomposition and the paper docs not deal with engines fueled by stored hydrogen. The paper concentrates mostly on the experimental work performed using catalytically decomposed methano…