The physical character of coal char formed during rapid pyrolysis at high pressure

Rapid pyrolysis was conducted in a drop tube reactor using seven coals under various operating conditions. In addition to dense char, porous chars (network char and cenospheric char) were formed by the rapid pyrolysis under certain conditions. Porous char was mainly composed of film-like carbon and skeleton carbon. The pyrolyzed coal char particles were characterized in detail. Morphology and bulk density of porous char were quite different from the dense char formed under the same conditions, but elemental composition and BET surface area were similar to each other. CO₂ gasification reactivity of porous char was lower than dense char in the later gasification stage, and this was ascribed to the low reactivity of skeleton carbon.     

Synthesis of CeO2-ZrO2 solid solution by glycothermal method and its oxygen release capacity

The glycothermal (GT) reaction of Ce acetate and Zr alkoxide directly yielded CeO₂-ZrO₂ solid solutions in a region of low Ce content ≤40 mol%. Of the CeO₂-ZrO₂ solid solutions obtained by the GT method and subsequent calcination at 500 or 800 °C, the sample with 20 mol% Ce content had the largest BET surface area. This sample exhibited the highest Ce-based oxygen release capacity in the whole Ce/Zr composition range. The oxygen release capacities of CeO₂-ZrO₂ solid solutions synthesized by the GT method were much larger than those of the samples prepared by a coprecipitation (CP) method. The Reitveld analysis and the repetitive reduction-oxidation experiment indicated that the CeO₂-ZrO₂ solid solution synthesized by the GT method has a homogeneous structure as compared with that prepared by the CP method.     

Consideration of Energy Dissipation for the Strength of Adhesive Joints

For some adhesive joints where the main difference is the degree of contact at the interface, failure occurs not at the interface, but some distance away in the polymer itself. This cohesive mode of failure in the polymer was always found to be the case in our studies of cupric oxide to branched polyethylene interfaces, even where the joint was so weak that the peeled surface seemed clean of the polymer to the naked eye. It was observed that the strength of the joint was associated with the coarseness of the texture of the peeled surface of the polymer. With a differential scanning calorimetry technique we have shown that the coarseness of the surface texture and therefore the strength of the joint, is a direct function of the amount of polymer involved in plastic deformation. The strength criteria for the adhesive joint of this kind is thus the energy of deformation and not the maximum tensile stress that the material can withstand.     

Deformation-induced martensitic transformation behavior in cold-rolled and cold-drawn type 316 stainless steels

We investigate deformation-induced martensitic transformation behavior in cold-rolled and cold-drawn specimens of type 316 stainless steel. Deformation-induced martensite preferentially nucleates at the twin boundary between the austenite matrix and a deformation twin. In the cold-rolled specimen, martensite formed at the twin boundary has a Kurdjumov–Sachs (K–S) relationship with both the austenite matrix and the deformation twin (“double K–S relationship”). In the cold-drawn specimen, two kinds of deformation twins with different twin planes are typically formed, and therefore deformation-induced martensites are formed where the deformation twin boundaries intersect: martensite thus has an imperfect “triple K–S relationship” with the austenite matrix and the two deformation twins. The complicated crystallographic orientation relationship between austenite and martensite grains strongly restricts the formation of some variants of deformation-induced martensites. Because of the difference in number of nucleation sites in the cold-drawn and cold-rolled specimens, martensitic transformation is more enhanced in the former than in the latter.     

Relation Between Foaming and Surface Properties of Detergent-Containing Lubricating Oil

The effect of water concentration on the foaming tendency of lubricating oil containing the detergent additives Ca-phenate and amide was investigated from a surface chemical standpoint. Foam volume, dynamic surface tension and surface viscosity were measured at various water concentrations. It was proved that the increase of surface viscosity with water content was the main factor affecting foaming in the case of Ca-phenate but, in contrast, the Marangoni effect played an essential role in the case of amide.     

First paralytic shellfish poison (PSP) infestation of bivalves due to toxic dinoflagellate Alexandrium tamiyavanichii, in the southeast coasts of the Seto Inland Sea, Japan

The mussel Mytilus edulis and the cultured ark shell Anadara broughtonii in the southeast coasts of the Seto Inland Sea were contaminated with paralytic shellfish poison (PSP) following the appearance of the dinoflagellate Alexandrium tamiyavanichii in early December 1999. A. tamiyavanichii plankton collected around the Straits of Naruto on December 3, 1999 showed PSP toxicity, of which 83 mol% was accounted for by GTX2, GTX3 and GTX4. Its specific toxicity was 112.5 fmol/cell, and one MU was equivalent to 7,200 cells. Toxicity values at the beginning of toxification were 4.7 MU/g for the ark shell and 7.3 MU/g for the mussel. In the former, the value remained at almost 4 MU/g, resulting in prohibition of marketing for about two months. In the latter, it sharply decreased to less than 4 MU/g. These bivalves collected during the toxification period were dissected into five tissues, mantle, adductor muscle, hepatopancreas, gills and "others", and submitted to high-performance liquid chromatography (HPLC). The cultured ark shell accumulated GTX2, GTX3 and STX as major components and GTX1, GTX4, GTX5, neoSTX, dcSTX and PX1-3 (C1-C3) as minor ones. The amount of GTX3 decreased with time, while STX tended to increase. At the early stage of PSP toxification, toxins were accumulated in the gills and "others", most of which were quickly detoxified. On the other hand, PSP of the toxified mussel consisted of GTX4 as a main component, and GTX1, GTX2, GTX3, GTX5, STX and PX1-2 (C1-C2) as minor ones. Its toxin composition pattern was similar to that of the ingested causative plankton. Its total toxin decreased soon after disappearance of the dinoflagellate. During the decrease of toxicity, PSP tended to be retained in the hepatopancreas, resulting in accumulation of 50 mol% of total toxin.     

Glare Generation Based on Wave Optics

This paper proposes a novel and general method of glare generation based on wave optics. A glare image is regarded as a result of Fraunhofer diffraction, which is equivalent to a 2D Fourier transform of the image of given apertures or obstacles. In conventional methods, the shapes of glare images are categorized according to their source apertures, such as pupils and eyelashes and their basic shapes (e.g. halos, coronas, or radial streaks) are manually generated as templates, mainly based on statistical observation. Realistic variations of these basic shapes often depend on the use of random numbers. Our proposed method computes glare images fully automatically from aperture images and can be applied universally to all kinds of apertures, including camera diaphragms. It can handle dynamic changes in the position of the aperture relative to the light source, which enables subtle movement or rotation of glare streaks. Spectra can also be simulated in the glare, since the intensity of diffraction depends on the wavelength of light. The resulting glare image is superimposed onto a given computer‐generated image containing high‐intensity light sources or reflections, aligning the center of the glare image to the high‐intensity areas. Our method is implemented as a multipass rendering software. By precomputing the dynamic glare image set and putting it into texture memory, the software runs at an interactive rate.     

Electrical characterization of crystal defects and oxygen in czochralski silicon using a gate-controlled diode

Defect generation in Czochralski (CZ) silicon crystal during heat treatment and effect of the defects on generation currents, measured by gate controlled diodes, were investigated. Sample wafers were obtained from an as-grown CZ silicon ingot which has a wide range of oxygen concentration but keeps other characteristics nearly constant. In the diode fabrication process, a two-step heat treatment method was utilized to control defect generation. It was found that stacking faults and dislocation loops, whose densities depend on oxygen concentration, increase the reverse current of the diode and the reverse current increases caused by defects vary with heat treatment condition. The most noticeable result was that the reverse current is enhanced by increasing oxygen concentration, even if no defect is observed in the device active region because of low defect density induced by heat treatment or of denuded zone formation. This result suggests the existence of some kind of electrically active defect caused by oxygen atoms in the crystal. Surface generation current is independent of crystal quality and two-step heat treatment conditions.