Analysis of oil obtained from mild hydrogenation of coal. 1. structural analysis of fractionated oil

Shin Yubari coal (86.7% C) was mildly hydrogenated repeatedly at 340–385°C under an initial hydrogen pressure of 10 MPa for 1 h, using Adkins catalyst. The product was extracted with benzene at 200°C and the residue was again reacted. Finally, benzene solubles were extracted with n-hexane, and n-hexane insolubles were hydrogenated under similar conditions at 380°C; the product was then extracted with n-hexane. The yield of total n-hexane solubles was 52.5%. Acid and base were extracted with sulfuric acid and NaOH, and the neutral part (50.2%) was chromatographed using an alumina column with 2.5% water and separated into 12 fractions. UV and IR spectra, ultimate analysis and ¹H-NMR spectra were obtained for each fraction and a structural analysis was carried out to obtain an image of each average structure. The aromatic ring numbers estimated from UV spectra and from structural analysis for each fractions agree well with each other; the average value was 3.2.     

On Markov Maintenance Problems

The applicability of Markov maintenance models is crucial. We need to fill the gap between theoretical and practical maintenance problems. A model is proposed for that purpose.     

Theoretical concentration of solar radiation by central receiver systems

Solar concentrations by central receiver systems have been calculated theoretically for various values of obliquity of the incident radiation, assuming that plane heliostat-mirrors, sufficiently small in dimension, cover a circular field without clearance. Through this calculation, the performance characteristics of this system such as the availability of the radiant energy incident on the heliostat-field, the distribution of interruption by an adjacent mirror, the optimum rim-angle for the mean area- and the mean volume-concentration and the attainable temperature were revealed. The study was extended towards the practical problem of decreasing the number of heliostats by increasing the dimensions of heliostat-mirrors, and the effect of increasing mirror-dimensions was argued for both plane and curved mirrors.     

Activity tests of various catalysts for hydrocracking of coal by means of high pressure differential thermal analysis

The activities of fourteen kinds of catalysts for the hydrocracking of Taiheiyo coal were examined by a high pressure differential thermal analytical method. Exothermic peaks appeared at low temperatures (420–430°C) when MoO₃TiO₂, NiY zeolite and CoY zeolite were used as catalysts, indicating that these catalysts are highly active compared with other catalysts including MoO₃CoOAl₂O₃. The qualitative analysis of gas and liquid products revealed that MoO₃TiO₂ and CoY are good catalysts for the liquefaction reaction. The hydrogenation ability of the catalyst is concluded to be more important than its acidic property.     

Sampling Rate Evaluation Of NO2 Badge: (I) In Indoor Environments

The sampling rate of a nitrogen dioxide (NO²) passive sampling badge was evaluated in indoor environments including an unoccupied research house, residential houses, and an office. Measurements from the NO² badges were compared with those of a chemiluminescent analyzer the EPA reference method, by placing them near to the sample inlet of the chemiluminescent analyzer In this study, we used a new sampling rate for the NO² badge placed in indoor environments (an overall mass transfer coefficient of 0.10 cm/s) smaller than the rate previously reported for the badge when used outdoors. The new rate provides more accurate measurements of NO, concentrations in indoor environments. Indoor NO² concentrations were also measured with the NO² badges exposed to a constant wind velocity provided by a wind tunnel. Since the measurements of the badge with a constant wind velocity agreed well with the reference method, the badges could be assumed to be a secondary reference measurement. With the badges used as the secondary reference measurement, we developed a portable wind tunnel to evaluate a personal exposure measurement by the badge. The results are presented in Environment International (Lee et al., 1993). Precision of the badge measurements was as good as an intraclass correlation coefficient of 0.9779. It was determined that placement of the badge should be at least 10 cm out from an indoor wall surface to avoid undersampling due to NO² gradients near the surface.     

High-speed InGaP/GaAs transistors with a sidewall base contactstructure

We have fabricated InGaP/GaAs double heterojunction bipolar transistors with a sidewall base contact structure. These transistors operate in both emitter-up and emitter-down modes. Symmetric characteristics of the cutoff frequency f_T=68 GHz and the maximum oscillation frequency f_max=31 GHz were obtained at a base-collector bias V_BC of 0 V. For emitter-down operation, f _T was found to reach a maximum of 78 GHz when the base-collector junction was forward biased at 0.9 V. The product of f _T for emitter-down operation and f_T for emitter-up operation was 5.3×10³ GHz², which is about six times that of previously reported SiGe heterojunction bipolar transistors     

Power swing analysis in a future metropolitan electric power system on a contingent trip of cryogenic high-power cables

A cryogenic power cable is expected to be capable of carrying bulk power as a main transmission line in a future metropolitan electric power system. It is important to establish a strategy of how to sustain power supply when such a highly densified power supply route trips from the network due to contingency. It is proposed here that the bulk power transmitted by the cryogenic cable could be distributed into the parallel conventional transmission lines by suitable circuit breaker operations in the system. In this process, power-flow routes are forced to be changed with a remarkable modification in the system configuration. In this paper, the power swings associated with the large power-flow change following contingent faults are analyzed by means of a transient network analyzer. It is found that the proposed system modification could be realized without any harmful power swing if the parameters in generators as well as in control devices have conventional magnitudes. It is shown also by simulations that the margin to occurrence in an unstable power swing is left sufficient even if the parameters deviate somewhat from the present magnitudes.     

Modulation of waveheight spectrum and radar cross section byvarying surface currents

This paper investigates the validity of the relaxation model which is generally used to describe the modulation of wind-generated ocean waves by slowly varying surface currents, and the applicability of the model to illustrating features observed in the radar images of internal wave wakes. The amplitude and phase modulations in the waveheight spectrum are examined for sinusoidal current variations; these changes are then translated into the radar cross section (RCS) modulation using the Kirchoff scattering theory. The present study concludes that: 1) the relaxation model is valid under intermediate to strong wind conditions and/or weak current signatures, and the conditions for the validity are given; 2) the relaxation model combined with the Kirchoff model could, under certain conditions, explain the differences in amplitude and phase between the P-band and L (C- and X-) band SAR images of ship-generated internal wave wakes observed during the 1989 Loch Linnhe experiment; and 3) the directional dependence of the relaxation rate enhances these differences     

Brominated and organophosphate flame retardants in selected consumer products on the Japanese market in 2008

The concentrations of traditional brominated flame retardants (BFRs) and organophosphate flame retardants (OPFRs) in new consumer products, including electronic equipment, curtains, wallpaper, and building materials, on the Japanese market in 2008 were investigated. Although some components of the electronic equipment contained bromine at concentrations on the order of percent by weight, as indicated by X-ray fluorescence analysis, the bromine content could not be fully accounted for by the BFRs analyzed in this study, which included polybrominated diphenylethers, decabromodiphenyl ethane, tetrabromobisphenol A, polybromophenols, and hexabromocyclododecanes. These results suggest the use of alternative BFRs such as newly developed formulations derived from tribromophenol, tetrabromobisphenol A, or both. Among the 11 OPFRs analyzed, triphenylphosphate was present at the highest concentrations in all the products investigated, which suggests the use of condensed-type OPFRs as alternative flame retardants, because they contain triphenylphosphate as an impurity. Tripropylphosphate was not detected in any samples; and trimethylphosphate, tributyl tris(2-butoxyethyl)phosphate, and tris(1,3-dichloro-2-propyl)phosphate were detected in only some components and at low concentrations. Note that all the consumer products evaluated in this study also contained traditional BFRs in amounts that were inadequate to impart flame retardancy, which implies the incorporation of recycled plastic materials containing BFRs that are of global concern.