Materials Literature
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Recent experimental studies by Hauver et al. reveal that the ballistic performance of ceramic targets depends entirely on how the ceramic is confined in a composite target. If the ceramic confinement is preserved, the penetrator is consumed by lateral flow at the ceramic-cover plate interface; this mechanism is known…
(1) Oxidation behavior of Si3N4 ceramics is affected by the composition of sintering aids and the weight gain due to oxidation tends to decrease with increasing SiO2/Yb2O3 ratio. In specimens with SiO2/Yb2O3 ratio from about 0.07 to 0.14, the weight gain is small. In specimens with SiO2/Yb2O3 ratio larger than about 0…
Three kinetic steps were observed for the complexations of Eu3+ and UO22+ by PAR [4-(2-pyridylazo)resorcinol] or PAN [1-(2-pyridylazo)-2-naphthol] in different buffered solutions. The first step can be assigned to the co-ordination of the nitrogen donor from the pyridine moiety of the ligand based on the dependencies…
100 keV O+ or N+ ion implantation was used to study the irradiation effect on the methane combustion activity of 1 mass%Pd, Pt, and Rh supported on γ-Al2O3 . The catalytic activity of both Pt/Al2O3 and Rh/Al2O3 was enhanced by the implantation, probably due to the improved dispersion of noble metals. On the other hand…
Phase formation has been studied in a nanosize composition of aluminum oxide and silicon dioxide. The temperature ranges for an intensive solid-phase reaction have been determined. A mechanism is proposed for phase formation in nanosize film compositions.
A novel method for the preparation of phase-pure K-β-alumina is reported by the gel-to-crystallite conversion method. Here, coarse gels of hydrated alumina Al2O3 ·yH2O (80<y<120) were reacted with ethanolic KOH, yielding crystalline K-inserted gibbsite or K-pseudoboehmite. Thermal decomposition of these precursors abo…
The ballistic behaviour of thick steel armour plate at different obliquities has been investigated. Ballistic experiments were conducted in the velocity range 300-800 mls at 0°, 15°, 30° and 45° obliquity .A steel, conical projectile or 6.1 mm diameter was impacted on a 10 mm thick steel armour plate. At 30° and 45° o…
The power of the Java programming language is briefly reviewed and the steps to create Java applets and applications are described. Examples taken from the literature were implemented to support chemical engineering education (http://www.labore.ufsc.br/java). Numerical methods such as LU decomposition, Newton-Raphson,…
A unique and theoretically sound method of deriving cross-sectional area along wool fibres is developed. Diameter values are derived from an equation based on an ellipse whose parameters are the semi-major and semi-minor axes and the angle of rotation of the ellipse. These parameters are used directly to calculate the…
The crystallisation of malachite has been studied in a system involving the counter diffusion of Cu2+ and CO=3 through a silica gel column at 25 °C. In such a system supersaturation is a function of time and position along gel column. Under these conditions kinetic variables are required in order to justify nucleation…
In this study, composition and seasonal variations of littoral algae in Lake Akşehir were investigated from June 1992- November 1993. In the littoral region, the algal flora were composed of 115 species belonging to Bacillariophyta, Charophyta, Chlorophyta, Cyanophyta, Euglenophyta. Bacillariophyta was predominant in…
Pitting corrosion behaviors for carbon steels in the working fluid for absorption heating and refrigerating systems were investigated. The fluid was an aqueous solution of 60% LiBr+0.2%LiOH+0.2%Li2CrO4. The testing temperature was 150°C which was 4°C below the boiling point. The critical depth concept which was develo…
Mg 3 MnH 7 was synthesised by reacting MgH 2 with manganese powder in a 3:1 molar ratio at 20 kbar and 1070 K for 120 min, and investigated by neutron powder diffraction on its deuteride. It crystallises with the hexagonal Mg 3 ReH 7 structure type (space group P6 3 /mmc, Z=2, a=4.7099(1), c=10.2861(3) A (hydride); a=…
Porous ceramics with a skeleton structure of aluminum borate (9Al2O3⋅2B2O3) whiskers were in-situ synthesized by firing a compact of mixed powder comprising aluminum hydroxide, boric acid and an additive of nickel oxide at 1150-1350°C. By adjusting the compacting pressure, a porous ceramic having a porosity of about 2…
Insulation degradation of high voltage equipment is one of the major concerns of electricity supply authorities. In particular current transformers have received a much attention since large numbers are installed in substations and their rate of failure has been relatively high. Conventional current transformers(CTs)…
To investigate the efficiency and long term stability of Ni-YSZ-cermet anodes as a function of current density and fuel utilization, various SOFC single cells were operated under realistic working conditions for approximately 700h. The gas composition present at different positions in a fuel cell stack, because of the…
Fracture in an aluminum conductor of an LSI(large-scale integrated circuit) is often caused by stress-induced diffusion of atoms along a grain boundary, which is called"stress migration". As the conductor is subjected to tensile hydrostatic stress at a high temperature due to thermal mismatch, it is important to under…
The Preisach and Jiles models for hysteresis are applied to reconstruct BH loops from measurement data for constructional steel St 37. The distribution function for the Preisach model is determined from all the available, 18, measured BH loops starting from the initial curve. The five unknown parameters in Jiles model…
A novel stilbazolium benzimidazolate derivative,i.e. 2-(4-{2-[4-(octylsulfonyl)phenyl]ethenyl}pyridinio)benzimidazolate 4a, was prepared by the quaternization reaction of 4-{2-[4-(octylsulfonyl)phenyl]ethenyl}pyridine with 2-chlorobenzimidazole, followed by deprotonation with aqueous ammonia. Poly(methyl methacrylate)…
Fe–N films containing less than about 30 at.% N were prepared on glass substrates and GaAs (100) single crystal wafers by the dual ion beam sputtering (DIBS) method. As nitrogen concentration and substrate temperature increased, α-phase, γ ′ -phase and ε -phase were formed on both substrates. The phase diagrams of the…