Gas engine lubricating oil degrades when it undergoes thermal decomposition by its exposure to high temperature. It is oxidized by air, and it changes the nitrate ester formed by the combustion products of fuel gas mixes. The degradation of the use oil causes about decrease in engine efficiency, the corrosion and the increase of wear for engine troubles. So, it is necessary to change the use oil beforehand at an appropriate period. Generally, gas engine lubricating oil consists of base oil and about ten kinds of additives in proper ratio. But now, degradation of gas engine lubrication can simply be evaluated by such broad guideline, as general analytic index. Therefore, it is difficult to specify the degradation conditions under which to decade the interval of effective oil.
In this study, the authors established a method of analysis which can evaluate degradation of base oil and specific additives qualitatively or quantitatively (a method to accurately evaluate the life of lubrication). The authors have revolved the results of their study because it has become now possible to show by an index results and effects of extreme pressure on additives and neutralization additions regardless of the old type used.

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The concept for contact time used as a scale-up factor of the isothermal system was expanded as apparent contact time to the temperature gradient system where the reaction field within the thermal diffusion column (TDC) reactor is limited to a higher temperature zone. The apparent contact time in the temperature gradient system was defined as LS/F using three operational factors of pyrogen length L[m], cross-sectional area of reactor tube S[m²], and methane feed rate F[mol/min]. The pyrogen temperature was set at 1400K. The dehydrogenative coupling of methane was carried out by varying single operational factors, and the following results were obtained. (1) When S is nearly 0.7×10^-3m², the methane conversion shows a maximal value. (2) When F is above 0.45mmol/min, the methane conversion shows a negative correlation with F. The methane conversion is kept constant when F is under 0.45mmol/min. (3) When L is lengthened from 0.195 to 0.360m, the methane conversion is increased remarkably. (4) Both product yields (gas and oil) and physical properties of products are related to the methane conversion. (5) When the LS/F value is less than 0.1m³min/mol, the methane conversion is increased with an increase in LS/F. Within the limited LS/F range, the apparent contact time could be applied as a scale-up factor of the TDC reactor. (6) It is considered that both recycling effects of ratio and zone within the TDC reactor lead to change in methane conversion.

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The controlled calcination of newly-synthesized group 13 element-containing silsesquioxanes, PhB[(Me₃SiO) (c-C₅H₉)₇Si₇O₁₁] 1 and [PPN]⁺{Ga[(Me₃SiO)(c-C₅H₉)₇Si₇O₁₁]₂}^-3b, as well as [HNEt₃]⁺{Al[(Me₃SiO)(c-C₅H₉)₇Si₇O₁₁]₂}^-2, [HNEt₃]⁺{Ga[(Me₃SiO)(c-C₅H₉)₇Si₇O₁₁]₂}^-3a, and [C₁₄H₁₈N₂H]⁺[(c-C₅H₉)₇Si₇O₁₂GaCl]^-4 at around 823K produces acidic oxides with high BET surface areas of 330-520m²g^-1 and uniformly-controlled micropores of 5.1Å diameter. Detailed investigation of these oxides revealed that the pore structures are not greatly influenced by the presence of the group 13 elements and counter cations. However, the acidic properties are greatly affected by the structure of the silsesquioxane precursors, and partly controlled by the group 13 elements and counter cations. In particular, oxides from 2, 3a and 3b were found to have high BET surface areas and large numbers of acidic sites. The oxides from 3a have relatively strong acidic sites, whereas oxides from 2 and 3b have weak and moderate strength acidic sites. The oxides from 4 do not show significant surface acidity. Differences in the dispersion of the oxides of group 13 elements in the silica matrixes, which are closely related to the structure of precursors, are considered partly account for the differences in acidic character.

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The effects of cetane number and fuel properties on diesel emissions, especially particulate matter (PM) emission and poly-nuclear aromatic hydrocarbon (PAH) emission, were investigated in a single-cylinder DI diesel engine. Normal paraffin fuel and isoparaffin fuel were used to prepare the base fuel. Various test fuels were prepared, by adding cetane number improver, aromatic compounds and heavy fraction to base fuel, to investigate the effects of cetane number, aromatic compounds, and heavy fractions on emissions. PAHs in the soluble organic fraction (SOF) were measured using the HPLC/UV method. Increased cetane number or aromatic compound content of the fuel caused greater soot emissions. Addition of heavy fraction to the fuel caused a higher soluble organic fraction (SOF) in the PM emissions. The PAHs were probably produced mainly from PAHs from unburned fuel. Experimental results using commercialized gas oil support this idea. Aromatic compounds have little effect on the in-cylinder formation of PAHs. This result suggests that PAHs and soot are produced by different pathways. Measurements of unburned hydrocarbon (THC) emissions, carbon mono-oxide (CO) emissions and oxides of nitrogen (NO_x) emissions corresponded to previous studies.

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The electronic hole-oxide ionic mixed conducting property in LaGaO₃ based oxide doped with Sr and Fe was investigated. It was found that Fe doped LaGaO₃ based oxide exhibited a superior mixed conduction, and an extremely large oxygen permeation rate from air to Ar was obtained on La_0.7Sr_0.3Ga_0.6Fe_0.4O₃. Patial oxidation of CH₄ into CO and H₂ was further investigated in the membrane reactor using LaGaO₃ based oxide as an oxygen separation membrane. In agreement with the simple oxygen permeation measurement, the highest CH₄ conversion was achieved at La_0.7Sr_0.3Ga_0.6Fe_0.4O₃. Therefore, La_0.7Sr_0.3Ga_0.6Fe_0.4O₃ can permeate oxygen over a wide range of oxygen partial pressure, and the amount of oxygen permeation, such as 8cm³/min cm² was attained at 1278K through a membrane 0.5mm thickness. The XRD measurement following the CH₄ partial oxidation showed that chemical stability of La_0.7Sr_0.3Ga_0.6Fe_0.4O₃ was satisfactorily high because there was no change in crystal phase was observed.

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A series of CoMo catalysts supported on TiO₂ with various Co/Mo molar ratios were prepared to investigate the relationship between the support and the promoting effect of cobalt. The catalytic activities of these catalysts were measured for the hydrodesulfurization (HDS) of dibenzothiophene (DBT). The HDS activity of Mo/TiO₂ catalysts increased remarkably with increased addition of cobalt up to Co/Mo ratio of 0.2 and then increased slightly above this value. The HYD activity of these catalysts remained almost constant with increasing Co/Mo ratio. Sulfur mobility on the sulfided CoMo/TiO₂ catalysts under the reaction conditions was investigated by a ³⁵S radioisotope tracer method using ³⁵S-labeled DBT. The rate constants of H₂S release (k_RE) for Co-promoted catalysts were approximately the same as those for non-promoted Mo catalysts at a given temperature, indicating that the addition of cobalt did not affect the mobility of sulfur over Mo/TiO₂ catalysts. In contrast, the amount of labile sulfur (S₀) increased remarkably with the addition of cobalt up to Co/Mo ratio of 0.2 and then increased slightly above this value. The increase in the catalytic activity with the addition of cobalt is probably due to an increase in the number of active sites.

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The effects of exchangeable sodium ion and H₂O in atmosphere on dealumination of USY zeolite by thermal treatment were studied by XRD and solid-state NMR. As a result of the thermal treatment of USY zeolite removed physical-adsorbed H₂O in atmosphere not containing H₂O, when the exchangeable sodium ion increased, the dealumination got more obstructive. In case of the samples containing few sodium, the silanol groups increased by the thermal treatment. On the other hand, as a result of thermal treatment of USY zeolite in 100% steam, with an increase in sodium contents, not only the crystallinity from XRD but also the short range order from NMR was remarkably decreased. The result indicates that the dealuminaton is promoted by the synergistic effect of both exchangeable sodium ion and H₂O in atmosphere. However, in the crystal region remained after the thermal treatment, the dealumination got more obstructive when the sodium contents were increased. It is suggested that this is caused by the diffusion of H₂O in the smallest crystal particles. In addition, in the several samples after the thermal treatment, appearance of the peak assigned to Si(2Al) at about -92ppm, which is normally observed at about -95ppm, can be considered to be due to the distortion of zeolite framework with the dealumination.

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