Deoxidation of Fe-C and Fe-Si Alloys under Reduced Pressures

The effect of the porosity of alumina crucible on the deoxidation in the vacuum melting of Fe-C alloys and that of the argon pressures on the deoxidation of the Fe-C alloys were investigated. These effects were considered from the relation between concentrations of carbon and oxygen in the Fe-C alloys. The rate of deoxidation and the oxygen concentration attainable in the vacuum melting of Fe-Si alloys were examined and results were considered from kinetic and equilibrium points of view

Notes on Gracilaria (Gracilariales, Rhodophyta) from Tosa Bay and adjacent waters I : Gracilaria chorda, Gracilaria gigas and Gracilaria incurvata.

Three species of Gracilaria (Gracilariales, Rhodophyta): Gracilaria chorda Holmes, Gracilaria gigas Harvey, and Gracilaria incurvata Okamura growing at Tosa Bay and adjacent waters (Kochi Prefecture, Japan) were reported and their characteristic features described. G. chorda as well as G. gigas was founded at Uranouchi Inlet, Tosa City (central Tosa Bay). The morphology of G. chorda varied greatly among the different habitats and seasons. Some young plants collected from April to May had long chord-like appearances without branchlets, while the older plants collected from June to July showed numerous filiform branchlets. However, reproductive organs of these plants agree well with the descriptions by Ohmi (1958) and Yamamoto (1978). Although the old fronds of G. gigas were similar to in shape to the aged plant of G. chorda in terms of vegetative appearance, it differed from the latter in regard to its spermatangial features and the presence of traversing filaments in the cystocarp. G. incurvata was found at Uranouchi Inlet and was also found at Kashiwajima, Ohtsuki town, and at Oh-hama, Tosashimizu City (western Tosa Bay). This species closely resembled G. textorii in regard to its flattened appearance, while the reproductive characteristics of this species also resembled those of the latter. However, a curved or twisted shape was shown only in G. incurvata

Energy Harvesting of Deionized Water Droplet Flow over an Epitaxial Graphene Film on a SiC Substrate

Abstract: This study investigates energy harvesting by a deionized (DI) water droplet flow on an epitaxial graphene film on a SiC substrate. We obtain an epitaxial single-crystal graphene film by annealing a 4H-SiC substrate. Energy harvesting of the solution droplet flow on the graphene surface has been investigated by using NaCl or HCl solutions. This study validates the voltage generated from the DI water flow on the epitaxial graphene film. The maximum generated voltage was as high as 100 mV, which was a quite large value compared with the previous reports. Furthermore, we measure the dependence of flow direction on electrode configuration. The generated voltages are independent of the electrode configuration, indicating that the DI water flow direction is not influenced by the voltage generation for the single-crystal epitaxial graphene film. Based on these results, the origin of the voltage generation on the epitaxial graphene film is not only an outcome of the fluctuation of the electrical-double layer, resulting in the breaking of the uniform balance of the surface charges, but also other factors such as the charges in the DI water or frictional electrification. In addition, the buffer layer has no effect on the epitaxial graphene film on the SiC substrate

Study of Magnesium Treated Nodular Cast Iron by Reducing in the Electric-Arc Furnace

Magnesium treated nodular cast iron (D. C. I.) was investigated by the reducing refining in the acid and the basic electric-arc furnace. By the reducing refining in arc furnace the oxygen and sulfur contents in molten metal were decreased, and so magnesium amounts necessary for the ductilization of graphite decreased. This reducing degree of magnesium amounts were examined. Further, the shrinkage cavities in the basic and the acid furnace were compared

Colonization of fouling invertebrate community on suspended man-made structures of varying slope angles

The effect of substratum slope on fouling invertebrates was examined on suspended man-made structures over a period of one year at the Uranouchi inlet of Tosa Bay, southern Japan. The experimental structures, made of concrete material, have three different slope angles, namely: 0°(horizontal), 45°(incline) and 90°(vertical). A total of 9 independent observations was performed from August 1996 - October 1997. At different periods of submersion, there was an observed succession of fouling invertebrates on the panels showing variations of dominant taxa among the three substratum slope angles. The common barnacles, tubedwelling amphipods and serpulid polychaetes appeared seasonally on the structures. As for the influence of substratum slope, the presence of fouling organisms on sloped substratum (45° and 90°) varied in the dominant taxa as well. Barnacles were markedly abundant on substratum with vertical slope, while the other organisms did not show any preference among the different slopes. A greater number of free-living worms were observed on substratum with small slope gradient

Research on the Structural Changes of Cast Iron by Contact Meltlng with Various Oxides

This investigation has been made to confirm how the structure of cast irons is influenced by oxides which constitute refractory and slag. Synthetic Fe-C and Fe-C-Si cast irons have been melted in contact with the various oxides under oxidizing atmosphere, argon and carbon monoxide at 1 atm. pressure at 1, 300 and 1, 350℃. The experimental results and the considerations are as follows : (1) In the case of the oxidizing atmosphere, the structure of synthetic Fe-C-Si cast irons becomes eutectic graphite or white cast iron structure. The structural changes are strongly controlled by the oxidation of the oxidizing atmosphere. (2) In the cases of argon and carbon monoxide, the original flake graphite structure becomes fine in the order SiO_2, MgO, BaO or CaO. In the case of Al_2O_3, the original structure is retained, and in the cases of BaO and CaO, the structure is most fine. The original sulphur content of the cast irons is also reduced in the similar order. (3) In the case of argon atmosphere, it may be deduced from the thermodynamic consideration that the Fe-C-Si alloys are deoxidized in the following processes. Si+2O+2MO (S)=M_2SiO_4, and Si+2O+MO (S)=MSiO_3. (4) In the case of CO atmosphere, it may be considered that the structural changes between flake graphite and fine eutectic graphite structure of Fe-C and Fe-C-Si alloys are due to the changes of sulphur contents of the alloys. In the case of argon atmosphere, it may be considered that the structural changes of Fe-C-Si alloys are due to the deoxidation and desulphurization of the alloys

Rate of Desulfurization of Ferroalloys in Vacuum Melting

The rate-limiting process in the desulfurization of ferroalloys in vacuum melting was confirmed by a kinetic study. The increasing order of rate of desulfurization is as follows : Fe-S<Fe-C-S<Fe-C-Si-S. In Fe-Si-S alloy, the rate of desulfurization is well explained from the evaporation of SiS from the surface of the melt. It is suggested that the rate-limiting process is the evaporation of desulfurization products from the surface of molten iron

Electron transfer characteristics of amino acid adsorption on epitaxial graphene FETs on SiC substrates

Clarifying the adsorption characteristics of biomolecules on graphene surfaces is critical for the development of field-effect transistor (FET)-based biosensors for detecting pH, DNA, proteins, and other biomarkers. Although there are many reports on biomolecule detection using graphene FETs, the detection mechanism has not yet been clarified. In this study, the adsorption behavior and electron transfer characteristics of 20 proteinogenic amino acids on graphene field-effect transistors are investigated. Large single-crystal graphene films were epitaxially grown on SiC substrates by a resist-free metal stencil mask lithography process then patterned by air plasma etching to form FET devices. Amino acids with different charge conditions (positive or negative charge) were introduced onto the epitaxial graphene surface in solution. The charge neutral points of the drain current vs gate voltage curves shifted in the negative gate voltage direction after the introduction of all amino acids, regardless of the type of amino acid and its charge condition. These amino acid adsorption characteristics agree well with previously reported protein adsorption characteristics on epitaxial graphene surfaces, indicating that the adsorption of proteins in the liquid phase occurs by electron doping to the graphene surface. These results indicate that non-specific protein binding always leads to electron doping of epitaxial graphene FETs

Design and synthesis of biotin- or alkyne-conjugated photoaffinity probes for studying the target molecules of PD 404182.

To investigate the mechanism of action of the potent antiviral compound PD 404182, three novel photoaffinity probes equipped with a biotin or alkyne indicator were designed and synthesized based on previous structure-activity relationship studies. These probes retained the potent anti-HIV activity of the original pyrimidobenzothiazine derivatives. In photoaffinity labeling studies using HIV-1-infected H9 cells (H9IIIB), eight potential proteins were observed to bind PD 404182