Materials Literature
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Abstract The thermal transformation of anhydrous alumina obtained by the decomposition of the lactate, citrate and tartrate of aluminium has been examined by thermal analysis(TGA and DTA), infrared spectrophotometry and X‐ray diffraction study. It is found that under an atmosphere of air the thermal decomposition of a…
Abstract [Tetrakis(4-methylpyridyl)porphyrinato]manganese(III) (MnIII(tmpp)) undergoes reversible one-electron transfer reactions in aqueous solutions. The half-wave potential of MnIII/II(tmpp) redox couple is −0.21V (vs. 3.33 M KCl, AgCl/Ag) between pH 4 and 12. On the other hand, the half-wave potential of MnIV/III(…
Abstract The vulcanization of butyl and natural rubbers by p -dinitrosobenzene (DNB), p -quinone dioxime (GMF) and p -quinone dioxime dibenzoate (dibenzo GMF) oxidized by various oxidants was investigated. Good curing efficiency ( E=1.2 ) was achieved for a butyl system containing GMF or dibenzo GMF oxidized by red le…
Abstract Experimental results evidenced the chemical structure of phosphonium salts to be essential in the process of corrosion inhibition for zinc and iron metals in the presence of Ph 4−y P + Ry, X − compounds (0 ≤ y ≤ 4) in an acid medium. Several steps are involved in a complex mechanism, each of which being enhan…
Fast fracture strength data on slip‐cast reaction‐bonded Si 3 N 4 determined by uniaxial MOR, biaxial ball‐on‐ring tests, and speed of rotational failure measurements were correlated using Weibull statistics and finite‐element techniques. The agreement between predicted and observed values demonstrated the applicabili…
Abstract A simple theoretical model which examines the effect of structural disorder on the mobility of diffusing particles in amorphous materials is suggested. So, following Anderson's ideas, it is assumed that structural disarray results in a probability distribution of energy barrier heights for diffusion around so…
Grain oriented glass-ceramics of fresnoite (Ba2TiSi2O8) and its modifications Sr2TiSi2O8 and Ba2TiGe2O8 have been prepared by recrystallizing glasses in a temperature gradient. Piezoelectric voltage coefficients g33 and hydrostatic voltage coefficient gh of these glass-ceramics are comparable to those of PVF2 and an o…
The $2{p}_{\frac{1}{2},\frac{3}{2}}$ levels in ${\mathrm{As}}_{4}$ and the $2{p}_{\frac{3}{2}}$ level in ${\mathrm{Se}}_{5,6}$ have been measured by x-ray photoelectron spectroscopy with the use of 1486.6-eV ($\mathrm{Al}K\ensuremath{\alpha}$) radiation. The $2{p}_{\frac{1}{2}}$ binding energies have been calculated f…
Twin‐roller quenching was attempted for 15 pseudobinary systems combining two chosen from the lithium ortho‐oxosalts, i.e. Li 3 BO 3 , Li 4 SiO 4 , Li 4 GeO 4 , Li 3 PO 4 , Li 2 SO 4 , and Li 2 WO 4 . Glassy flakes were obtained in almost all systems. Glass formation was easier in systems containing large amounts of L…
The c-axis oriented thin films of SbSI are prepared by the recrystallization of the amorphous SbSI films. The recrystallized films show the pyroelectric properties and have a dielectric capacitance between 0.2-0.5 μF/cm2 and the tan δ <1%.
The Submerged Demineralizer System (SDS) has been used at Three Mile Island-Unit 2 (TMI-2) to process more than 1.5 million gallons of water contaminated as a result of the March, 1979 accident. The SDS has processed approximately 315,000 gallons of water accumulated in tanks in the Auxiliary Building, approximately 6…
The thermodynamic relation between the discontinuity of the longitudinal elastic compliance at the glass transition and the long-wavelength density fluctuations in the glass is rederived using the formal framework of linear response theory. Analogous new relations are derived for the discontinuities of the specific he…
It is generally recognized that the particle size distribution (PSD) of powders plays a very significant role in powder compaction and sintering. However, particle size distribution data are generally presented in the form of one number (mean diameter). In the case of PSD data obtained by sedimentation, analysis of th…
An extensive study of the 51 V NMR in VO 2 has been made between 4.2 K and 600 K, particularly laying stress on the analysis of the temperature dependence of the nuclear relaxation rate 1/ T 1 . In the metallic (M) phase ( T > T t =340 K) an exchange-enhanced Korringa relaxation process for 1/ T 1 is observed and the…
The electrical conductivity of sintered pellets of nickel–nickel oxide mixtures of various compositions has been measured as a function of temperature in the range 700–1000 °C. The electrical conductivity of nickel oxide single crystals in air as well as in oxygen pressures corresponding to nickel–nickel oxide equilib…
Gold, platinum and tungsten films were deposited by low energy input (7 mA, 450 V), or high deposition rate (80 mA, 1500 V), diode sputter coating and by ion beam sputter coating. Film structures on Formvar coated grids and on the surface of coated erythrocytes, resin embedded, sectioned, and recorded at high magnific…
Abstract New silicon‐containing polyimides have been prepared by the reaction of pyromellitic dianhydride (PMDA) and 3,3′,4,4′‐benzophenonetetracarboxylic dianhydride (BTDA) with organosilicon diisocyanates having the following general structure: magnified image where R 1 = R 2 = CH 3 and C 6 H 5 . Thermal propertie…
A formulation of the three dimensional eddy current problem is presented. The magnetic vector potential is used in regions with source currents and conducting material and the total magnetic scalar potential is employed elsewhere. The continuity of the normal component of flux density and tangential component of field…
Abstract With the use of solid state carbon-13 NMR, changes in the structure of natural rubber and cis -polybutadiene were observed spectroscopically. Cis-trans conversion has been shown to occur in the naturaal rubber by the rearrangement of the allylic free radical. At least four structurally different methyl groups…
A theoretical approach is presented for predicting the strengthening of brittle materials subjected to a residual stress distribution represented by a polynomial series. In the approach, the stress intensity factor for a surface crack is derived incorporating the effect of crack closure. The crack‐closure distance is…