Improvement of fatigue properties of fillet lap joints by local TIG arc heating

Summary

The temper embrittlement affecting the HAZ of 2 1/4Cr-1Mo steel subjected to SR treatment and subsequent reheating is investigated with synthetic HAZ specimens and compared with the embrittlement observed in specimens tempered in the same temperature range without SR treatment (direct tempering). The synthetic HAZ specimens are de-embrittled on application of suitable SR treatment (975 K × 5 hours). Subsequent reheating at 775 to 925 K, however, produces four different types of embrittlement in the specimens. These are the second, third, fourth, and fifth types of embrittlement already identified in the direct-tempered specimens. The first type of embrittlement which occurs during direct tempering in the shortest time range does not appear after SR treatment. The second type (the short-term type), which occurs over a wide time-temperature range during direct tempering, only appears in a narrow range after SR treatment. The third and fourth types (the long-term types) occur just as intensively as during direct tempering. The fifth type (the high-temperature type) also appears after SR treatment. This suggests that embrittlement in the short-term range is to some extent suppressed by SR treatment, but the types of embrittlement arising in the long-term range and high-temperature range occur after SR treatment as well. The ‘step cooling process’ can be applied for short-term detection of temper embrittlement in this steel. However, there is considered to be little or no embrittlement promotion effect due to step cooling per se.     

Effect of the genistein metabolite on leptin secretion in murine adipocytes in vitro

Soy isoflavonoids have many useful properties. However, they are metabolized in vivo, including in humans. The effect of the metabolism of soy isoflavonoids on their properties is not fully understood. We have isolated the bacterial strain SY8519, which has been shown to metabolize daidzein to O-desmethylangolensin and to produce 2-(4-hydroxyphenyl)propionic acid from genistein. According to chiral HPLC analysis, the 2-(4-hydroxyphenyl)propionic acid obtained from the bacterium was optically active. To determine the absolute stereochemistry of the microbial product, we prepared (S)-2-(4-hydroxyphenyl)propionic acid from (S)-2-phenylpropionic and concluded that the microbial product had an R-configuration by chiral HPLC analysis. We also applied the metabolite to mouse adipocytes and found that 2-HPPA was less effective at reducing leptin secretion than the parent compound genistein. Our results suggested that ‘O-desmethylangolensin-production’ attenuates the effect of soy isoflavonoids by reducing not only the activity of daidzein but also that of genistein.     

Development of optimization model for power system operation,outline of model design and verification of output

Osaka Gas Co., Ltd., jointly with NTT DATA Mathematical Systems Inc., has developed unit‐commitment model for optimizing dispatch of power generation units. Main purpose of this development is to simulate the future world of electric power system in accordance with national energy policy aiming to introduce large amount of renewable energy as well as vitalized cross‐border power exchange via PX market to enhance economically‐efficient power system operation. The model incorporates not only constraints of supply‐demand balance but also constraints of operating reserves, regulation reserves, maximum CO2‐emissions, etc.     

Plasticity initiation and subsequent deformation behavior in the vicinity of single grain boundary investigated through nanoindentation technique

The initiation of plasticity and the subsequent state in the vicinity of a single grain boundary during indentation-induced deformation were investigated to understand an elementary step of a stress-strain behavior of polycrystalline materials. Nanoindentation measurements on several points on a single grain boundary and the grain interior of an interstitial-free steel and an analysis on the pop-in behavior and the plastic nanohardness were carried out. The pop-in load P ^c that was obtained on the loading curve is different for each measurement. However, the loading curves overlap one another and the unloading curves coincide as well after the pop-in event. The nanohardness Hn has no dependence on the P ^c in the range of 150–550 μN. The relation between P ^c and Δh can be expressed as a simple cubic polynomial function based on a geometrically necessary dislocation loop model. The fitted function differed for various grains with different crystallographic orientations.     

Anhydrous proton-conducting electrolyte membranes based on hyperbranched polymer with phosphonic acid groups for high-temperature fuel cells

The two different molecular weight hyperbranched polymers (HBP(L)-PA-Ac and HBP(H)-PA-Ac) with both phosphonic acid group as a functional group and acryloyl group as a cross-linker at the chain ends were successfully synthesized as a new thermally stable proton-conducting electrolyte. The cross-linked electrolyte membranes (CL-HBP-PA) were prepared by their thermal polymerizations using benzoyl peroxide and their ionic conductivities under dry condition and thermal properties were investigated. The ionic conductivities of the low molecular weight CL-HBP(L)-PA membrane and the high molecular weight CL-HBP(H)-PA membrane were found to be 1.2 × 10⁻⁵ and 2.6 × 10⁻⁶ S cm⁻¹, respectively, at 150 °C under dry condition, and showed the Vogel–Tamman–Fulcher (VTF) type temperature dependence. Both membranes were thermally stable up to 300 °C, and they had suitable thermal stability as electrolyte membranes for the high-temperature fuel cells under dry condition. Fuel cell measurements using a single membrane electrode assembly cell with both cross-linked membranes were successfully performed.     

Chemical-Labeling-Assisted Detection of Nucleobase Modifications by Quantum-Tunneling-Based Single-Molecule Sensing

Quantum-tunneling-based DNA sensing is a single-molecule technique that promises direct mapping of nucleobase modifications. However, its applicability is seriously limited because of the small difference in conductivity between modified and unmodified nucleobases. Herein, a chemical labeling strategy is presented that facilitates the detection of modified nucleotides by quantum tunneling. We used 5-Formyl-2′-deoxyuridine as a model compound and demonstrated that chemical labeling dramatically alters its molecular conductance compared with that of canonical nucleotides; thus, facilitating statistical discrimination, which is impeded in the unlabeled state. This work introduces a chemical strategy that overcomes the intrinsic difficulty in quantum-tunneling-based modification analysis—the similarity of the molecular conductance of the nucleobases of interest.     

A salient‐pole synchronous generator with permanent magnets between the field poles

In this paper, a new salient‐pole synchronous generator (SG) termed the PMa‐SG is presented. In the PMa‐SG, permanent magnets (PMs) are placed between the pole shoes to reduce the magnetic saturation in the field poles. By using finite element analysis (FEA), the internal magnetic fields and basic characteristics of a 2.8‐MVA PMa‐SG are compared with those of a conventional SG of the same size, and the reduction effect of the magnetic saturation of the PMs is examined. The FEA simulations are also validated by experiments on a 2.0‐kVA prototype machine. The PMs placed between the pole shoes reduce the magnetic saturation in the pole bodies and pole tips and effectively increase the terminal voltage and output power. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 174(4): 58–67, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21132     

The effect of increasing interfacial strength in micro fluidic system for heat detection with micro-sandglass shaped interlocks

Microsystem Technologies - We present a useful method to increase interfacial strength for micro fluidic system of calorimetry biosensor. The micro-sandglass shaped posts were fabricated by deep...