Calculation of the standard heat capacities of crystalline oxides in the Fe-O-Ti system

Our earlier experimental studies of the solid-phase reduction of disseminated lump ores demonstrate that an oxide lattice transforms into a metal lattice via the saturation of the oxide crystal lattice by charged oxygen vacancies. Low-charge metal cations appear in the oxide crystal lattice, and they are related to oxygen vacancies by the condition of local electrical neutrality. As oxygen vacancies are accumulated (i.e., during reduction), the number of oxygen vacancy-low charge cation complexes in the initial oxide increases. The total composition of the oxide phase in the range of a crystal lattice of a certain type changes continuously from the initial oxide to the end product of reduction, i.e., to the lower oxide or a metal. Therefore, it is necessary to determine the thermal characteristics of not only all possible stoichiometric compounds in the M-O system but also MO_x oxides of variable compositions. Equations for calculating the standard heat capacities of complex stoichiometric oxides and oxides of variable compositions in the Fe-O-Ti system are derived using a mathematical model developed earlier, and these characteristics are calculated.     

Synthesis of minerals using alternative energy sources

A technology for the synthesis of synthetic minerals (using the example of spinels) using a low-temperature plasma flame is developed. The diagnostic properties of spinels are identified.     

Computers and translation: integrating IT into undergraduate foreign language learning

Abstract There are still many institutions of higher education in the UK, both universities and polytechnics, that have not taken on board the application of information technology to foreign language learning. Apart from considerations of cost, there is also the problem of time—deciding how best to use the limited time at one's disposal for exploring computer applications to foreign language learning. Both problems may be compounded by the mistaken belief that effective use of this 'new' technology necessarily involves learning one or more programming languages. This paper endeavours to show that recent advances in both software and hardware have produced computing tools of particular interest to translation and the translator, and that, since translation is a reality for large numbers of undergraduates in the UK, such tools represent an obvious starting point for the introduction of IT into the undergraduate curriculum.     

Low temperature and strain rate dependence of fracture stress and fracture toughness on thin Fe40Ni40B20 amorphous ribbon

The fracture stress and the critical stress intensity factor of the Fe₄₀Ni₄₀B₂₀ amorphous metallic ribbons 20 μm thick were measured in the temperature range 4.2–300 K and at deformation rates from 3.3×10⁻⁶ to 1.25×10⁻³ m⁻¹ with the aim to obtain more information on the condition for the onset and development of the inhomogeneous plastic deformation and fracture.     

Simple approach to analysis of switched-capacitor circuits with nonideal op-amps

A possible method for the simulation of nonideal op-amps with a finite gain and bandwidth by means of an equivalent SC circuit, containing ideal components, is presented. The approach is extended by the case of an op-amp with non-switched input SC building blocks.     

Effect of the magnetic-flux variations on SQUID stability

The oscillation dynamics of a nonhysteretic, one-contact superconducting quantum interferometer under low-frequency modulation of an external magnetic flux has been studied. It is shown that even in the case of adiabatic, equilibrium, and nonhysteretic operation modes of a superconducting ring enclosed by a weak link, there can appear chaotic oscillations. The conditions of chaos arising have been considered analytically and numerically; mechanisms and destruction scenarios of periodic oscillations have been studied. The stochastic instability could impose limitations on the increase in sensitivity of nonhysteretic SQUIDs, which was earlier predicted to be high enough.