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Carbonates are ubiquitous minerals carrying important information on aqueous environments where they precipitated on the Earth and space. While their ideal chemical formulae are denoted as simple as MCO3 or M1M2(CO3)2 (M: metal cations), natural carbonates generally form solid-solution series and their compositions deviate from the ideal formulae. Since their cation composition due to the substitution provides a sensitive indicator for chemical and thermodynamic environments of aqueous solutions where they precipitated, their composition analysis has been widely carried out from the environmental/geochemical/astrochemical aspects. However, in widely used back-scattered electron and energy dispersion X-Ray analyses, samples should be generally sliced and/or their surface be polished prior to the measurements. For analyzing rare samples with small sizes, such as ones sampled from deep-sea and/or meteorites and asteroids, a non-destructive method without any pretreatments has been strongly desired. Here, a novel analytical method for discriminating various carbonates with Raman micro-spectroscopy is demonstrated, showing that the biaxial plot of the peak frequencies of their lattice modes linearly moves upon partial substitution of the cations. The cation substitution leads to linear movement in the biaxial map, and the slopes of the movement were different for Mg2+-Fe2+ and Mn2+-Fe2+ substitutions. This finding suggests that the micro-Raman analysis would be a non-destructive analytical method for evaluating the relative amount of Mg2+, Fe2+, and Mn2+ in dolomite-ankerite-kutnohorite solid-solution series, as well as Mg2+/Fe2+ ratio for magnesite-breunnerite-siderite. It would be helpful for analyzing the present and past terrestrial and cosmochemical environments. Graphical abstract

For exploitation of a new class of aromatic micelles, we synthesized a bent pentacene-based amphiphilic molecule through Diels-Alder reaction. The amphiphiles bearing two trimethylammonium tethers assemble into a spherical aromatic micelle, with an average core diameter of 1.5 nm, in water at room temperature. The new aromatic micelle efficiently encapsulates perylene bisimide (PBI) dyes and graphene nanosheets (GNS) in water. The encapsulated PBI dyes form a parallel stacked dimer, exhibiting characteristic absorption and emission bands. In addition, the encapsulated GNS are composed of few-layer graphene sheets with an average lateral size of ∼7 nm, as confirmed by Raman spectroscopy. The resultant, aqueous host-guest complexes are stable even after three weeks in water under ambient conditions.

Radiation-induced graft polymerization was applied to prepare membranes for multilayer immobilization of laccase, which has biodegradation ability for bisphenol A (BPA). Glycidyl methacrylate (GMA) was grafted onto porous polyethylene membranes as the monomer of polymer brushes, and aminoethanol (AE) was introduced to the grafted GMA membrane, creating unfolded polymer brushes that serve as a good support for multilayer immobilization of laccase. The objectives of this study were as follows: adjustment of space velocity (SV) for optimum performance; enhancement of stability in organic media through moisture retention; biodegradation of BPA at continuous operation; and investigation of the effects of redox mediators. Laccase and membrane activities were increased at higher SVs as a result of stronger substrate transport. The 1.85% moisture retention as a result of high-density AE containing polymer brushes demonstrated the improved stability of immobilized laccase over free laccase in methanol-containing solutions. BPA was removed with an activity of 0.11 mol/h/kg-membrane. The effects of three major laccase mediators on BPA oxidation was studied, and only 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) was shown to increase the oxidation of BPA to 100% at low SVs. Improved stability of laccase and high removal rates in the continuous biodegradation of BPA were achieved by the presented method.

A gemini-type amphiphilic molecule, constituted of two V-shaped polyaromatic amphiphiles linked by a linear acetylene spacer, was synthesized. The gemini amphiphile assembles into a well-defined aromatic micelle (ca. 2 nm in core diameter), providing higher stability in water even at low concentration (0.09 mm) and high temperature (>130 °C). Unlike common gemini amphiphiles with aliphatic chains, the present amphiphile and its micellar assembly emit green and orange fluorescence (ΦF =33 and 9 %), respectively. Despite strong and multiple π-stacks of the polyaromatic panels of the amphiphiles, the water-soluble gemini aromatic micelle incorporates medium-size to large hydrophobic compounds into the frameworks. Interestingly, the guest binding capability toward large planar molecules was enhanced by more than two times through the pre-encapsulation of spherical molecules in the cavity.

Crystal orientations of creep damaged Type 316 stainless steel were measured by 10 organizations using the same specimens, passed in a round robin, in order to investigate the scatter in material damage assessment using the electron backscatter diffraction (EBSD) technique. The measurements were performed according to the EBSD measurement guideline issued by the Society of Material Science, Japan. Two misorientation parameters, the local and intra-grain misorientations, were calculated using mapping data of measured crystal orientations. It was shown that the area averaged local and intra-grain misorientations correlated well with the degree of the inelastic strain caused by the creep damage. Although the area averaged local misorientation showed eminent scatter, the scatter in the area averaged intra-grain misorientation was relatively small. The scatter in the area averaged local misorientation was deduced to be brought about by the error in the crystal orientation measurements. Since the accuracy of the crystal orientation measurement depends on various factors and is difficult to control, the correlation between the degree of the creep damage and the local misorientations obtained by one SEM/EBSD system is difficult to apply to other SEM/EBSD systems. On the other hand, the area averaged intra-grain misorientation is not affected much by the error in the crystal orientation measurements and the values obtained by various organizations using different SEM/EBSD systems were almost the same. It was concluded that the area averaged intra-grain misorientation can be used for measurement of the creep damage (inelastic strain). The empirical relationship between the area averaged intra-grain misorientation and the degree of the creep damage can be shared regardless of the SEM/EBSD system used.

Crystal orientation measurements using electron backscatter diffraction (EBSD) have been utilized to quantify plastic strain. However, detectability and accuracy of quantification of the plastic strain were not clear. In this study, a round robin measurement using deformed Type 316 stainless steel specimens was launched between 11 organizations using the same specimens. The magnitude of induced plastic strain was 0.25%–10.28%. Two kinds of misorientation parameters, the local misorientation and intra-grain misorientation, were quoted as the measure of the plastic strain. The intra-grain misorientation exhibited a clearer correlation with the degree of plastic strain than the local misorientation did. It was found that the EBSD measurement could detect the plastic strain of more than 1%. It was shown that the variation of the misorientation parameters between the organizations largely depended on the accuracy of crystal orientation identification, which was quantified by the background noise Bn. The error could be reduced by applying the smoothing filter. The EBSD measurements were concluded to be capable of quantifying the degree of plastic strain with accuracy of 0.5% for the strain less than 2%.

The effects of various factors such as the surface finish condition of specimens, lubricant and argon gas flow rate on both the creep deformation behavior and time to rupture for 2.25Cr-1Mo low alloy steel used for boilers by small punch testing were studied. There was little difference in both the small punch creep deformation behavior and time to rupture due to the difference in surface roughness between #1200 polished specimens and those in mirror polished condition. The application of BN lubricant to the specimen surface resulted in the decrease in time to rupture, due to the lowering of friction coefficient. Furthermore, the time to rupture increased according to the increase of argon gas flow rate. The depth analysis by μ-ESCA for surface oxide film formed in an argon gas atmosphere demonstrated that the formation of Fe-rich oxide film with a low friction coefficient produced a decrease in time to rupture under a low argon gas flow rate condition. The formation of Cr-rich oxide film with high friction coefficient produced the increase in time to rupture under high argon gas flow rate condition. This suggests that the reliable control of argon gas flow rate is very important in order to evaluate the life of material by small punch creep testing.

This paper proposes a circuit topology to draw additional dc power outputs from a dc transmission line by series-connected circuits. It is based on a conventional concept of HVDC tap but the HVDC tap is duplicated in this paper in order to reduce current fluctuations on the dc transmission line. Inversed switching pattern between the two HVDC tap results in small current fluctuation and realizes additional low dc power outputs. This circuit topology is expected to be applied to a dc transmission system for offshore wind power, etc. In this paper, the operating characteristics are discussed in detail based on simulation study. The condition to achieve the soft-switching is also revealed. In addition to this, operating characteristics of the total system are verified by numerical analysis to investigate the availability of the proposed circuit.