Materials Literature
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This paper presents a review of the state of the art developments in the pitting corrosion fatigue of aircraft structural materials. Mechanisms that govern the nucleation and growth of pitting and corrosion fatigue (CF) are briefly addressed. Some of the developments made in the author's laboratories in proposing the…
Abstract A transparent LiAl5O8 : Co2+ film was prepared by the sol–gel method using LiNO3, Al(i-OC3H7)3, and Co(NO3)2·6H2O. The microstructure and optical properties of the film were examined using X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), optical absorption,…
Grafted copolymers which consist of a polydimethylsiloxane backbone and poly(ethylene oxide-co-propylene oxide) pendant groups are used as surfactant to stablize the bubbles in flexible polyurethane foam. The final properties such as air flow through the foam are significantly affected by the structure of the silicone…
New approaches to produce injection moldable elastomeric foams with porosities in the micrometer range have been developed. In the first approach, water is dispersed within the siloxane network by first preparing a reverse emulsion in the presence of an appropriate surfactant. Porosity is then generated by evacuation…
Various extensions of Onsager theory based on the second virial approximation are constructed in order to describe nematic P-phases in ribbon polymer solutions. If the average coil shape is anisotropic and the concentration is not too high, the coils can be considered as anisotropic solid objects and an ordinary expan…
In this work, we investigated a kinetic study of the reaction between poly(acrylic acid) (PAA) and metal oxides (MO: ZnO, CaO, CuO, Al 2 O 3, Cr 2 O 3 ) by using infrared spectroscopic techniques. The experimental data were quantified by a base-line method. The amounts of reactant, reaction time, mixing speed, solvent…
We examine substrate/overlayer experiments and the equations commonly used to quantify overlayer thicknesses. Comparisons with accurate Monte-Carlo simulations show that using attenuation lengths (rather than inelastic mean free paths) eliminates most of the error due to elastic scattering without increasing the compl…
Dihydroneopterin triphosphate (H2NTP) 2'-epimerase from Escherichia coli catalyzes the epimerization of H2NTP to dihydromonapterin triphosphate (H2MTP). The enzyme was purified 954-fold to apparent homogeneity by a combination of ammonium sulfate fractionation and column chromatography of Cibacron blue 3GA dye ligand,…
Abstract The backscattered electron signal (BSE) in the scanning electron microscope (SEM) has been used for investigation of a specimen surface composition (COMPO mode). Creation of a material composition map is difficult because the dependence of backscattering coefficient η on the atomic number Z for Z > 40 is n…
Abstract Parameters of wetting dry fibers with non‐Newtonian liquids are studied experimentally. Rheological tests show that seven of the 13 test liquids adhere to Newtonian behavior with a wide range of viscosities 3 < μ < 30,000 mPa·s. The other six liquids show shear‐thinning behavior with different flow indi…
Abstract The incorporation reaction of zinc(II) and cadmium(II) into 21-(4-nitrobenzyl)-5,10,15,20-tetrakis(4-sulfonatophenyl)-23H-porphyrin (NO2Bz(Htpps)4−; HP4−) and the dissociation reaction of the metalloporphyrins ([MP]3−) have been studied spectrophotometrically at I = 0.1 mol dm−3 (NaNO3). The formation rate of…
The effects of ambient pressure ranging from 101 up to 3040 kPa and temperature from 233 up to 353 K on burning rate of both high and low fuel content Si-Pb3O4 mixtures have been investigated. Also tests have been made to further reduce pressure effects using additions of metal fluorides. Sodium and calcium fluorides…
Magnesium oxide-supported polytitazane copper complex is prepared and found to be a very effective catalyst for the Baeyer-Villiger oxidation of ketones and cyclohexanol in the presence of an aldehyde as a reductant under an atmospheric pressure of oxygen at room temperature. The δ-valerolactone and δ-caprolactone can…
The dynamics of guanidinium nitrate studied by inelastic neutron scattering, infrared and Raman spectroscopy is reported. The experimental frequencies were assigned to the fundamental modes of nitrate and guanidinium ions on the basis of qualitative considerations. The assignment of the out-of-plane bending mode γ(N–H…
X-ray diffraction based on the comparison between the experimental and the calculated (20,11) and (02,31) powder profiles enabled determination of the structural characteristics of a Tunisian nacrite. The nacrite has space group Cc and the stacking mode is 2M. The two-layer periodicity could be described by a rotation…
The inherent properties of diamond make it an ideal material for detectors in the high rate, high radiation environments near the collision point of future colliders such as the LHC. We have constructed charged particle position sensitive detectors using high quality chemical vapor deposited (CVD) diamond. Using detec…
The liquidus isotherms for the Ga–As–Bi system were determined at 973 and 923 K in the Ga–As–GaAs region. The liquid phase epitaxial growth of GaAs from Ga–As and Ga–As–Bi solutions were investigated. The addition of ten atomic percent of Bi to the Ga–As solution increase the growth rate of the grown epilayers nearly…
Challenges in the integration of ferroelectric nonvolatile memories with complementary metal-oxide-semiconductor (CMOS) technology for low-voltage and low-power applications are discussed. The main driving force for commercialization is to take advantage of the true high-speed (100 ns), low-voltage (0.9 V) write poten…
Abstract A novel method for the preparation of water‐soluble polypyrrole graft copolymers with polyamines or polyimines is described. The polyreaction is performed in acidic solution by using chemical oxidants, e.g. iron(III) chloride or ammonium peroxodisulfate. The graft copolymers showed electrical semiconductivity…
What can be done with radioactive waste? This extremely difficult question has not really been answered anywhere in the world; yet it must be answered. Like death and taxes, radioactive waste is with us—it cannot be wished away. This special, five-article issue of PHYSICS TODAY reviews the technical problems and risks…