An X-ray photo-electron spectroscopic study of surface treatments of stainless steels

The effects of surface treatments on the surface composition and structure of Type 304 and 316 stainless steels were studied by X-ray photo-electron spectroscopy. The content of chromium and iron in the surface film depends considerably on the surface treatment method, while the nickel content in the film is significantly lowered compared to bulk composition regardless of the method. Some surface treatments which result in a significant enrichment of chromium in the surface film on the steels give the highest pitting potential. When the specimens were left for at least a day in contact with air, a certain amount of a magnetite-like compound was formed in the surface film. This fact is responsible for the ennoblement of the pitting potential by ageing after treatment.     

Possibility of an embedded system for ultrasound-based measurement of the distances to two target objects

We developed an embedded system by which to simultaneously measure the distances to two target objects, such as an obstacle and a wall. The embedded system incorporates a set of ultrasound sensors, analog circuits, and a microcomputer to automatically measure the distances to the two targets, and displays the information on a liquid crystal display. For a single target, a large iron-plate wall, at a distance of from 0.5 to 2.75 m, the percentage error in the detected distance was less than 5%. For two targets, such as an acrylic resin cylinder (object 1) in front of a wall (object 2), the percentage error in the detected distances was less than 5% in most cases. In some cases, however, there were significant measurement errors. Nevertheless, since the proposed measurement system revealed the exact distance in the majority of cases, this system could be applied to industrial and autonomous moving robots.     

Nondestructive measurement of machining-induced amorphous layers in single-crystal silicon by laser micro-Raman spectroscopy

Laser micro-Raman spectroscopy was used to examine silicon wafers precision machined by diamond tools, and the results were compared with transmission electronic microscopic results. It was found that near-surface amorphous layers were generated by machining and there was a strong correlation between the thickness of the amorphous layer and the Raman intensity ratio of the amorphous phase to the crystalline phase. This finding provides the feasibility of a fast, inexpensive, nondestructive and quantitative measurement approach for subsurface damages of semiconductor materials by using laser micro-Raman spectroscopy. The effective measurement range was experimentally investigated and the sensing limits were theoretically discussed from the aspect of light scattering and light absorption with a double-layer material model.     

Total Syntheses and Chemical Biology Studies of Hymeglusin and Fusarilactone A,Novel Circumventors of β-Lactam Drug Resistance in Methicillin-Resistant Staphylococcus aureus

Hymeglusin, a previously known eukaryotic hydroxymethylglutaryl-CoA (HMG−CoA) synthase inhibitor, was identified as circumventing the β-lactam drug resistance in methicillin-resistant Staphylococcus aureus (MRSA). We describe the concise total syntheses of a series of natural products, which enabled determination of the absolute configuration of fusarilactone A and provided structure-activity relationship information. Based on previous reports, we speculated that the target protein of this circumventing effect may be MRSA bacterial HMG−CoA synthase (mvaS). We found that this enzyme was dose-dependently inhibited by hymeglusin. Furthermore, overexpression of the MRSA mvaS gene and site-directed mutagenesis studies suggested its binding site and the mechanism of action.     

Purification and characterization of an l-amino acid oxidase from Pseudomonas sp. AIU 813

An l-amino acid oxidase was found from a newly isolated strain, Pseudomonas sp. AIU 813. This enzyme was remarkably induced by incubation with l-lysine as a nitrogen source, and efficiently purified using an affinity chromatography with l-lysine as ligand. The enzyme oxidized l-lysine, l-ornithine and l-arginine, but not other l-amino acids and d-amino acids. The oxidase activity for l-lysine was detected in a wide pH range, and its optimal was pH 7.0. In contrast, the oxidase activity for l-ornithine and l-arginine was not shown in acidic region from pH 6.5, and optimal pH for both substrates was 9.0. The enzyme was a flavoprotein and composed of two identical subunits with molecular mass of 54.5?kDa. The N-terminal amino acid sequence was similar to that of putative flavin-containing amine oxidase and putative tryptophan 2-monooxygenase, but not to that of l-amino acid oxidases.     

A simplified measurement of adhesion between p-aramid fiber and polypropylene

It is well known that p-aramid fiber is difficult to reinforce the polypropylene (PP) matrix with high adhesion. In addition, the conventional adhesion measurements were always extremely inconvenient. Therefore, it is necessary to simplify the adhesion measurement and also produce a p-aramid/PP composite with high adhesion. In this work, “Bundled filaments pull out (BFPO)” method as a simplified measurement was applied to measure the adhesion properties of p-aramid fiber/PP composite. The suitable processing parameters of the p-aramid fiber/PP composite preparation were also discussed from BFPO test results. Feasibility of this BFPO method was examined through comparing the tendency of adhesion between p-aramid fiber and PP by BFPO method and micro-droplet method. The resultant p-aramid fiber/PP composite prepared at 180°C with a 3?mm embedded length showed a high degree of PP impregnation. The adhesion tendency of p-aramid fiber/PP composites was mainly the same when comparing the results using BFPO method and micro-droplet method.     

Development of externally pressurized small-size conical-shaped gas bearings for micro rotary machines

We have developed externally pressurized small-size conical shaped gas bearings for micro rotary machines such as gas blowers, compressors, and medical devices. The bearings are lightweight and enable machines and devices to be downsized by reducing the number of parts, since the journal and thrust loads can be supported by a pair of bearings. The conical bearings (diameters 8 mm and 10 mm) were designed and the manufacturing techniques were considered. The bearing type is a double-row inherent orifice bearing with four feed holes per row. The shape accuracy of the manufactured bearings is within the design limits, being less than 0.005 mm in both roundness and cylindricity. The surface roughness (arithmetic average roughness) of the parts is 0.0002 mm. The static characteristics were calculated and validated by testing on manufactured bearings. Comparative agreement was obtained between the measured and designed values. The proposed calculation method presents as a relatively simple approach for predicting the bearing characteristics. The test rotor exceeded 350 Hz (21,000 rpm) in the rotational test, and whirl vibration was absent. During testing, the maximum rotor vibration amplitude was 0.0125 mm (corresponding to an eccentricity ratio of 0.89).     

Preparation of Fatty Acid Methyl Esters by Selective Methanolysis of Polar Glycerolipids

KOH in aqueous methanol catalyzes selective methanolysis of polar glycerolipids with O-ester-linked acyl residues, while triacylglycerols and sterol esters are inert in the solution. Based on these findings, a convenient and reliable method was developed for the preparation of fatty acid methyl esters (FAMEs) from polar glycerolipids in lipid mixtures without prior isolation. Methanolysis of polar glycerolipids was completed within 2.5 min by vortexing or 20 min by shaking with 0.7 M KOH/70% (v/v) methanol in the presence of hexane at 30 °C. The yields of FAMEs obtained by the present method were greater than 95%. The method was applied successfully to gas chromatographic analysis of the fatty acid compositions of polar glycerolipids in seed oil and blood. No obvious differences were found between the fatty acid compositions determined by the present method and those determined by conventional methods, including lipid extraction with chloroform/methanol followed by isolation of polar lipids by chromatography. The fatty acid composition of polar glycerolipids, including phospholipids, can be determined readily in many crude samples.     

Equity implications of two burden-sharing rules for stabilizing greenhouse-gas concentrations

This paper focuses on the equity aspects of international burden sharing for global CO₂ emission stabilization. It first summarizes and classifies equity principles proposed in the published literature of the field. Of these, the authors selected three major equity principles, i.e., egalitarian equity, horizontal equity, and proportional equality (often referred to also as sovereign equity) to carry out a detailed examination of two sets of quantitative emission entitlements, which are based on two burden-sharing rules, i.e., the equal emissions per capita approach and the carbon intensity approach. The two burden-sharing rules were chosen as not only particularly popular, but also because their application results in distinctly different burden sharing among countries.     

Evaluation of lifecycle CO2 emissions from the Japanese electric power sector in the 21st century under various nuclear scenarios

The status and prospects of the development of Japanese nuclear power are controversial and uncertain. Many deem that nuclear power can play key roles in both supplying energy and abating CO₂ emissions; however, due to severe nuclear accidents, public acceptance of nuclear power in Japan has not been fully obtained. Moreover, deregulation and liberalization of the electricity market impose pressure on large Japanese electric power companies with regard to both the operation of nuclear power plants and the development of the nuclear fuel cycle. Long-term Japanese CO₂ reduction strategies up to 2100 are of environmental concern and are socially demanded under the circumstances described above. Taking these factors into account, we set the following two objectives for this study. One is to estimate lifecycle CO₂ (LCCO₂) emissions from Japanese nuclear power, and the other is to evaluate CO₂ emissions from the Japanese electric power sector in the 21st century by quantifying the relationship between LCCO₂ emissions and scenarios for the adoption of nuclear power. In the pursuit of the above objectives, we first create four scenarios of Japanese adoption of nuclear power, that range from nuclear power promotion to phase-out. Next, we formulate four scenarios describing the mix of the total electricity supply in Japan till the year 2100 corresponding to each of these nuclear power scenarios. CO₂ emissions from the electric power sector in Japan till the year 2100 are estimated by summing those generated by each respective electric power technology and LCCO₂ emission intensity. The LCCO₂ emission intensity of nuclear power for both light water reactors (LWR) and fast breeder reactors (FBR) includes the uranium fuel production chain, facility construction/operation/decommission, and spent fuel processing/disposal. From our investigations, we conclude that the promotion of nuclear power is clearly a strong option for reducing CO₂ emissions by the electric power sector. The introduction of FBR has the effect of further reducing CO₂ emissions in the nuclear power sector. Meeting energy demand and reducing CO₂ emissions while phasing out nuclear power appears challenging given its importance in the Japanese energy supply.