Materials Literature
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Crystal growth was carried out by the Bridgman method for six substances of the Cs2 BX 4-type with β-K2SO4 structure, where B=Zn, Co and X=Cl, Br, I. The dielectric constants were measured to investigate their phase transitions. It has been shown that Cs2ZnI4 and Cs2CoI4 exhibit clear first order transitions at 93K an…
X - ray diffraction studies of polycrystalline Pb[(Fe 1/3 Sb 2/3) xTiy Zrz ]O 3 with x + y + z = 1, x = 0.1 and y = 0.43 – 0.47 have been performed in the temperature range between 23°C to 380°C. The results indicate that below 220°C rhombohedral and tetragonal phases coexist; above 220°C the cubic symmetry phase only…
In this letter the line tension associated with screw dislocations is considered. First, it is shown that screw dislocations can be identified with negative line tensions on various cross-slip planes in cubic crystals; analytical or numerical conditions for negative line tension are given. Secondly, the relative magni…
The ac conductivity of cuprate glasses based on the unconventional network former PbO is reported in the frequency range 102–105 Hz and in the temperature range 80–450 K. Analysis of the conductivity data has been made in the light of different existing theoretical models. It is observed that, among them, the correlat…
The polarization and dielectric properties of model ferroelectric crystals of the triglycine sulphate group (TGS) and the A2BX4 group (Rb2ZnCl4) were studied. General laws of dielectric relaxation near the Curie point were determined.
We report a detailed evaluation of Ge‐substituted LaNi 5 for electrochemical application as a negative electrode in alkaline rechargeable cells. Alloys with small substitutions of Ge for Ni show operating pressures, chargeability, cyclic lifetime, and kinetics for hydrogen absorption and desorption all superior to tho…
The analysis of elastic instabilities in metal cylinders when subjected to electromagnetic fields (Littlefield, 1996a) is extended in this work to include elastic-plastic flow. The cylinder is assumed to be infinitely long and perfectly conducting. The Prandtl-Reuss elastic-plastic material model is the assumed consti…
Abstract Polyphthalamide(PPA)/polyamide(PA) blends were analyzed to determine the effect of PA addition to PPA on melting point, glass transition temperature, dynamic modulus, and heat distortion temperature. Results indicate that the choice of PPA and the choice of PA for the blend systems affects not only the above…
Addition of lime to paving asphalts is known to inhibit oxidative aging of pavements. The mechanism of the action of lime in retarding oxidation is not known. In this work, an asphalt was mixed with a vanadium chelate that is known to strongly promote oxidation in asphalts. This enhancement of oxidation was largely ne…
Several telechelic compounds were prepared by terminal functionalization of poly(oxyethylene) diacid via the reaction of the carboxylic groups with different aromatic amines. Starting from the telechelic diacid, the corresponding diacid chloride was prepared with thionyl chloride after which the compound was allowed t…
Abstract The fracture toughness of semicrystalline nylon 6, amorphous nylon 6IcoT, and their blends can be represented as the inherent toughness plus the toughness due to the formation of the crack tip plastic zone. The inherent toughness originates mostly from the molecular alignment near the crack tip plus a small c…
Abstract The interaction of simulated nuclear waste borosilicate glass with acid solutions (pH = 2, pH = 4) was studied under static conditions (i.e. without refreshment of corroding solution) at 30, 60 and 90°C. Tests with stirred and unstirred solution were compared. The rate of glass dissolution (given by the rate…
Abstract Silicate and germanate glasses studied by X‐Ray diffraction methods (WAXS) show characteristic features concerning the first peak of their scattering functions (FSDP: first sharp diffraction peak). Shapes and positions of the FSDPs develop systematically with composition. The shape of the FSDPs can only be de…
Geothermal energy is an alternative renewable energy resource that has proven itself technically and economically feasible as a nonpollulanl electric power source. The Denizli-Kizildere geothermal energy region is the first major geothermal energy resource project in Turkey, with an estimated potential of 200 MW. The…
Abstract The effect of a magnetic field on the hydrogenic shallow donor impurity is investigated with the use of a variational method. Two different expressions describing the photoionization cross‐section for donor‐conduction band transitions are obtained both in absence and presence of an applied strong magnetic fie…
Cast duplex stainless steels are known to be susceptible to embrittlement after long term ageing at intermediate temperatures (300-400°C). This embrittlement is related to the spinodal decomposition that occurs in the ferrite phase. Steels of equivalent composition after undergoing the seemingly same heat treatment ex…
High temperature X-ray diffraction and quenching experiments of mullite single crystals with Al2O3:SiO2 ratio 2:1 have been performed to investigate the stability of the oxygen vacancy ordering close to the melting point of mullite. The experiments show that the structure of mullite exhibits an extremely stable, tempe…
Abstract Smectites are a major mineral group often found in the clay fraction of soils. Our objective was to evaluate the effect of pedologic environments on smectites in the arid Carrizo Plain, California. Six pedons (one Argixeroll, three Haploxeralfs, one Natrargid, and one Salorthid) were described and sampled alo…
Abstract Fe 2 O(SeO 3 ) 2 , frequently obtained in various chemical systems by low-hydrothermal treatment of SeO 2 and FeC 2 O 4 · 2 H 2 O, has been investigated using single-crystal X-ray diffraction. Crystal data (at room temperature): space group Pccn , a = 6.639(2) Å, b = 12.839(4) Å, c = 13.266(4) Å, V = 1130.8(6…
The reforming of a paraffinic naphtha was studied in order to determine the influence of chlorination during the run. Experiments were performed at 505°C, 15 kg cm−2, WHSV = 4, H2: HC= 4, and with or without an 8 h initial period of deactivation at 1 kg cm−2. A commercial Pt–Re/Al2O3 (0·3% Pt, 0·3% Re, 0·04% S, 0·15%…