Residual oil cracking combined with hydrogen production by steam-iron reaction

A new residual oil upgrading process has been developed. Residual oils were cracked over an iron oxide catalyst with simultaneous generation of hydrogen. The newly-developed iron oxide catalyst containing CaO and Cr₂O₃ was found to be a good catalyst for this process because it exhibited stable activity in the steam-iron reaction in the laboratory experiment and also in a large scale pilot plant. Effects of these foreign oxides on redox cycles were investigated. The catalyst was designed so as to maintain the stoichiometric balance between the reduction of magnetite and the oxidation of wustite by adding CaO and Cr₂O₃.     

Studies on chains of bubbles rising through quiescent liquid

The liquid velocity profile induced by a chain of bubbles is studied theoretically and a comparison with measurements is made. The wake velocity and the bubble shape involved in the theoretical development are considered based on the wake theory and the previous empirical relation for single bubbles, respectively. The shape and wake volume of chain bubbles can be treated in the same manner as those of single bubbles by using relative velocity. As a result, using the previous results of the drag coefficient and shape of single bubbles enables the prediction of the rising velocity of chain bubbles.     

FREE RADICALS FORMED IN HYDROTREATED COAL LIQUID AND INFLUENCE OF OXYGEN

The behavior of radicals formed in hydrotreated coal liquid with heat treatment and the influence of oxygen have been investigated by electron spin resonance (e.s.r.) spectroscopy. A set of e.s.r. spectral lines identified as phenalenyl radical appears from 50^°C as the oil is heated in argon atmosphere. The radical concentration is enhanced with temperature, reaches a maximum between 130 and 150^°C and then decreases at higher temperatures. The radical is very stable even at 200^°C for the sample hydrotreated under mild condition, whereas the radical in the sample treated under severe conditions disappears drastically from 150^°C. When oxygen is introduced in the oil, the radical is converted into semiquinone and/or aryloxy radicals and stable molecules. The treatment in the presence of oxygen at higher temperatures is considered to accompany the formation of other aryloxy radicals by the reaction of aromatic hydrocarbons and oxygen.     

New oxygen donors formed at 700 °C in silicon

Donor formation at 700 °C was studied by infrared absorption, etching, transmission electron microscope, resistivity, and spreading resistance measurements in Czochralski grown silicon. The donor concentration is related to the oxygen-precipitate density, oxygen reduction, and carbon reduction by annealing at 700 °C. The donor distribution corresponds to the distribution of oxygen precipitates observed after annealing. The proposed donor is an oxygen precipitate nucleated at a carbon site. The oxygen-related donor formation not only occurs in the bulk of samples but also in the denuded zone. Donor-related microdefects do not seriously influence the threshold voltage in metal-oxide-silicon field-effects-transistors, but are expected to decrease carrier lifetime at the surface of the denuded zone.     

Molecular orientation behaviour of uniaxially stretched poly(vinyl chloride) film: 1. Birefringence: effect of plasticizers and draw ratio above and below Tg

In order to investigate the orientation behaviour of a non-crystalline chain polymer, plasticized and unplasticized poly(vinyl chloride) films (PVC) are chosen for investigation. The following two orientation distribution functions are postulated to calculate the second moment of the molecular orientation: (a) for the unplasticized film drawn below the glass transition temperature the distribution function derived from an affine deformation mechanism is applied; (b) for the all plasticized films or for the films drawn above the glass transition temperature a compound distribution function derived from the affine deformation mechanism and that of a rubber-like chain (Langevin model) proposed by Roe et al is applied. The parameters which are included in the distribution function, viz. the ratio of the affine part to the Langevin part, the ratio of polyene to carbonyl in a heat treated film and the segment number of the Langevin chain, can be evaluated experimentally. The intrinsic birefringences of normal and heat treated unplasticized and plasticized films are estimated theoretically on the basis of additivity of band polarizabilities. The calculated birefringences and orientation distribution functions show good agreement with measured values.     

Nonlinear magnetic levitation control by four-point attraction

Rubber components of production equipment are a significant source of contamination in the fabrication of VLSI devices and other semiconductor products. One approach to solving this problem is to use a magnetic levitation system for noncontact transfer. The force nonlinearity of magnetic circuits presents a problem, particularly when the gap between the magnets and the levitated vehicle is small. Linearization methods that allow effective control do exist, but in this paper an alternative method not based on linearization is proposed. The design involves magnetic levitation control by 4-point attraction. The experimental results indicate that the idea is an effective one.