Materials Literature
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The diatom genus Cyclostephanos Round is invalidly published because a legal type was not designated at the time of description. Round apparently intended for Stephanodiscus novaezeelandiae Cleve to be the type of the genus. That species is proposed here as the lectotype of the name Cyclostephanos and a lectotype is p…
Dielectric measurements in the frequency range (104 to 10-3 Hz) are presented for opaque PMN [Pb(Mg1/3Nb2/3)O3] hot-pressed ceramic samples. Equivalent results for transparent lanthanum-doped PMN and PMN (90%): PbTiO3 (10%) are also presented. Observation of “Anomalous Low-Frequency Dispersion” has new implications fo…
An analysis of the use of fines destruction during batch crystallization based on the population (number) balance is presented. The effects of operating policy and fines crystal cut size and destruction rate are examined in detail for two cases viz. natural and controlled cooling respectively. It is predicted that use…
Abstract Magnetic particles of iron oxide were blended into portions of a high molecular weight sample of poly(dimethylsiloxane) which were then peroxide cured in a magnetic field. Strips cut from the resulting elastomers parallel and perpendicular to the magnetic lines of force were studied with respect to their equi…
Titanite CaTiOSiOa from calc-silicate rocks of Gebel Umm Shagir, Egypt, associated with garnet, p,'roxene, scapolite, calcite and quartz, contains up to 11 wt.9o Nb2O5, 6 wt.9o Al2O3 and2 *t.Vo V2Oj. Other elements present in minor amounts are Fe, Ta, Sn, and F. The main substiturions are2Ti : Nb + AI, Ti + O = Al + (…
Fifteen reference patterns of boride, silicide, selenide, telluride and oxide ceramics are reported. Included in the 15 reference patterns are data for three oxide phases which are related to high critical temperature (T c ) superconducting materials: BaCuO 2 , BaCuSm 2 O 5 and BaCuYb 2 O 5 . Four other patterns are i…
A nonsteady-state cooling method has been used to measure the thermal diffusivity (α) of nonwovens. The method is relatively simple and requires a minimum of spe cialized equipment. The calculations required to obtain α from cooling curves are somewhat involved but can be easily performed on a small computer. The appa…
Abstract ESCA and contact‐angle measurements were used to characterize the surfaces of polystyrene films exposed to SF 6 , CF 4 , and C 2 F 6 plasmas. SF 6 plasmas cause loss of aromaticity in the polystyrene surface region via saturation of the phenyl ring and/or carbon‐bond breakage and subsequent fluorination. C 2…
Sinterability of undoped, MgO‐doped, and TiO 2 ‐doped Al 2 O 3 has been examined by applying reported sintering equations. The order of sinterability was MgO‐doped ∼ undoped≪ TiO 2 ‐doped Al 2 O 3 in the initial and intermediate stages of sintering, but a relative sintered density at 1600°C for 1 h occurred in the ord…
Neutron inelastic scattering experiments have been performed to investigate the long-wavelength spin dynamics of the amorphous isotropic ferromagnet ${\mathrm{Fe}}_{100\mathrm{\ensuremath{-}}\mathrm{x}}$${\mathrm{B}}_{\mathrm{x}}$ (for x=14 and 18). At both iron concentrations this system exhibits Invar behavior. The…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPreparation and characterization of (alkylperoxo)cobalt(III) porphyrins: first direct evidence for metal-carbon bond homolysis in dioxygen insertion reactionsMaureen J. Kendrick and Walid Al-AkhdarCite this: Inorg. Chem. 1987, 26, 24, 3971–3972Publication Date (Print):Decemb…
Abstract The split-Hopkinson pressure bar (SHPB) technique has been adapted to measure the dynamic response of soil to impulse loads. The experimental technique is relatively simple and can investigate soil response in regimes beyond the capabilities of current equipment used for dynamic soil laboratory investigations…
Principal component analysis (PCA) was performed on the correlation matrix of 16 characters measured on each of 129 specimens of the freshwater centric diatom Stephanodiscus niagarae from 14 lentic North American habitats. There were two major independent components to overall silicification. Firstly, larger valves we…
The measured electrical conductivity of ${(\mathrm{AgI})}_{x}{(\mathrm{Ag}\mathrm{P}{\mathrm{O}}_{3})}_{1\ensuremath{-}x}$ glasses for $0<x<0.6$ follows a power-law characteristic of site percolation. The percolation threshold is 0.3, the critical exponent 3.3, the vulnerability 4.8, and the number of contact si…
Abstract External standard and internal standard calibrations are important procedures for achieving high accuracy in X-ray powder diffraction studies. The theoretical basis as well as procedures for obtaining calibration curves are given. Methods and examples of selecting Standard Reference Materials (SRMs) which are…
Sepia cartilage collagen (pepsin-extracted) in acetate buffer (pH = 2.98) forms micelles at a particular concentration below which they do not normally form. The critical micelle concentration (cmc) of the collagen was determined in buffer as well as in SDS, cetyltrimethylammonium bromide (CTAB) and Tween-80 micellar…
A comparison of several fracture toughness determination methods based upon the use of cracks emanating from a Vickers hardness indent to the bulk techniques of double cantilever beam and single edge notch beam is made in a tough zirconia material which shows little evidence of transformation toughening based on the a…
Three molecular combinations, each consisting of two disk-shaped (tripheny-lene units) and one rod-shaped mesogen (azobenzene- and azobophenyl-units) were synthesized with the aim of generating new liquid crystal phases. Two molecular geometries were realized thereby. The trimesogen 1 with laterally fixed rod-like mes…
Nanotechnology is concerned with manufacturing to dimensions or tolerances in the range 0.1-100 nm. It plays a key role in many areas including materials processing, mechanical engineering, optics and electronics. Technologies for manipulating materials at or near the molecular level are coming increasingly into use.
It is difficult to delineate Cyclotella, Cyclostephanos and Stephanodiscus—the three most taxonomically diverse, predominantly freshwater genera of the Thalassiosiraceae. Cyclostephanos was originally distinguished by a Stephanodiscus-like exterior of fasciculate striae and raised radiating costae, and a Cyclotella-li…