Thermodynamic assessment of the Cu−Pt system

A CALPHAD assessment of the Cu−Pt system has been carried out. Two and four sublattice models were applied to describe the Gibbs free energies of ordered phases where the contribution of SRO is taken explicity into account through the reciprocal parameters. The disordered fcc A1 and liquid phases were treated as substitutional solutions. A consistent set of parameters for the phases in the Cu−Pt system as obtained, and those parameters can satisfactorily reproduce the experimental phase equilibria and thermodynamic properties, such as enthalpies, activity of Cu, and long-range order parameters. This paper was presented at the International Symposium on User Aspects of Phase Diagrams. Materials Solutions Conference and Exposition, Columbus, Ohio, 18–20 October, 2004.     

Synthesis of ternary intercalation compounds of carbon fiber

Ternary intercalation compounds of carbon fiber (ICCF) were successfully synthesized by soaking pitch-based carbon fibers in solvents such as 1,2-dimethoxyethane (DME) or tetrahydrofuran (THF) containing dissolved alkali metals (lithium, sodium, or potassium). ICCF with stage-1 and random stage was synthesized in alkali metal–DME and potassium–THF systems using different types of carbon fibers. However, ICCF with stage-1 could not be synthesized in lithium– or sodium–THF systems using carbon fibers with a low graphitization degree. Furthermore, the influence of the graphitization degree in the synthesis of ICCF was discussed. The graphitization degree of the host carbon fiber, in addition to the dimensions and steric structure of the intercalated complex affected the formation of TICCF.     

Syngas to iso-paraffins over Co/SiO2 combined with metal/zeolite catalysts

Selective production of gasoline ranged iso-paraffins from synthesis gas was performed in a consecutive dual reactor system, in which Fischer–Tropsch reaction was carried out over Co/SiO₂ catalyst in the upper reactor and hydroconversion of the Fischer–Tropsch hydrocarbons occurred over precious metal/zeolite catalyst in the lower reactor. Results indicate that the product distribution of traditional Fischer–Tropsch synthesis was significantly modified and high selectivity to iso-paraffins was achieved with the presence of metal/zeolite catalyst in the lower reactor. A significant effect of metals (Pt and Pd), zeolites (zeolites of β and USY), and the preparation methods (impregnation and ion exchange) of the metal/zeolite catalyst on the iso-paraffins selectivity and product distribution was clearly observed. This was explained based on the property of the metal for hydrogen spillover and the acidic and structural properties of the zeolite in the bifunctional metal/zeolite catalyst.     

An x-ray photo-electron spectroscopy study of the passivity of amorphous Fe-Mo alloys

The increase in molybdenum content in amorphous FeMoPC alloys facilitates the passivation in 1 N HCl in contrast to crystalline iron base alloys without chromium. An attempt was made to clarify the effect of molybdenum through the composition of surface film analyzed by XPS. The passive film consists mainly of ferric oxy-hydroxide, while a large amount of hexavalent molybdenum species is found in the surface film formed in the active region. The effect of molybdenum is interpreted as follows: the active dissolution necessary for proceeding the passive film formation leads to the precipitation of hexavalent molybdenum species on the alloy surface and as a result, the active dissolution is stifled. This fact leads to the passivation with the aid of iron ions which are already accumulated in the alloy/solution interface during the active dissolution.     

Mechanical properties and micro-fracture behaviors of flat braided composites with a circular hole

In this study, attention is paid to braided fabrics as the form of reinforcing fiber in composite materials and the influence of a circular hole on the mechanical properties of a flat braided composite is investigated. Two types of specimens were prepared: a flat braided bar with a braided hole which fiber bundle continuously oriented around the hole and with a machined hole. From the results of static tensile test, the strength of the flat bar with a braided hole was higher than that of the one with the machined hole. Furthermore, difference of damage propagation in the two types of flat braided composites with a circular hole was confirmed by micro-damage observation and factors that caused initial micro-fracture obtained by experiments were identified by numerical approaches.     

The art of massive storage: a Web image archive

Museums can make their entire collections available to the world via the Internet. The Thinker ImageBase, the San Francisco Fine Arts Museums' online art image database, demonstrates issues involved in managing large storage systems and delivering their contents to users.     

An XPS study of the passivity of a series of iron—chromium alloys in sulphuric acid

The composition and structure of passive films formed on a series of iron—chromium alloys in de-aerated 1M H₂SO₄ were quantitatively studied by XPS. The chromium content of passive film increased drastically at ca. 13 %Cr of the bulk alloy composition, whereas no composition change was found in the surface of the substrate alloy immediately under the passive film. The high corrosion resistance of iron—chromium alloys with high chromium content is attributed to the protective nature of hydrated chromium oxy-hydroxide, which is the main constituent of passive films on the alloys containing chromium of 12.5 at. % or more.     

Neutralization of Lipopolysaccharide by Heat Shock Protein in Pediococcus pentosaceus AK‐23

About 1000 species of bacteria are present in the human intestine. Some Gram‐negative bacteria such as Escherichia coli or Salmonella spp. among intestinal bacteria have lipopolysaccharide (LPS), which might induce inflammation of human intestines. Actually, LPS, especially its lipid A constituent, is toxic. Small amounts of LPS in bacteria cause inflammation of mucosa and other tissues in humans. Such bacteria may be regulated by beneficial lactic acid bacteria to maintain human health. Many lactic acid bacteria show cancer prevention activity and anti‐inflammatory activity in intestines. Recently, Pediococcus pentosaceus AK‐23 was isolated from fermentative vegetable pickles for neutralization of LPS. For this study, a protein for LPS neutralization was purified partly from P. pentosaceus AK‐23. For this study, a protein for LPS neutralization was purified partly from P. pentosaceus AK‐23, by ultrafiltration using a 300 kDa membrane and a 100 kDa membrane after cell wall digestion by lysozyme. Gel running blue native electrophoresis revealed the existence of a 217 kDa protein. The band of the protein having the ability to bind LPS on the gel was analyzed for amino acid homology. As the result, it is revealed as part of a subunit of heat shock protein (HSP). Furthermore, it displayed LPS binding or hydrophobic motifs. The protein neutralized LPS to release fatty acid as myristic acid and glucose from polysaccharide. These findings suggest that HSP in P. pentosaceus AK‐23 neutralizes LPS to decompose it compising fatty acid and polysaccharide.     

Behavior and mechanisms of Ni/ScSZ cermet anode deterioration by trace tar in wood gas in a solid oxide fuel cell

In order to determine both the criterion for diagnosing the deterioration of Ni/ScSZ cermet anodes in solid oxide fuel cells (SOFCs) by tar contaminants in wood gas and the tolerance limit of tar in wood gas for such anodes, the influence of tar concentration in wood gas on anode deterioration behavior was examined by means of scanning electron microscopy. We found that the anode degradation mechanism consisted of three phenomena: the disappearance of Ni particles, the destruction of sintered ScSZ, and carbon deposition. Furthermore, the Ni particle disappearance occurred at lower tar concentrations than did sintered ScSZ destruction and apparent carbon deposition. Therefore, we propose that the disappearance of Ni particles be set as the criterion for confirming deterioration of Ni/ScSZ cermet anodes in SOFCs by tar. On the basis of this criterion, the tolerance limit of toluene in fuel gas was determined to be 3 g/Nm³ when the operating temperature, steam to carbon molar ratio, and current density were 1073 K, 1, and 0.5 A/cm², respectively. The tolerance limit for tar for the fuel cell constructed herein was one to two orders of magnitude higher than that for internal combustion engines.