Kobelco Eco-Solutions (Japan)

In this paper, a new bolt axial force reduction coefficient was calculated and evaluated to assess the reduction in bolt axial force due to both increased cable tension and aging, with the aim of rationalizing the design methodology for intermediate joints. First, the change in bolt axial force due to increased cable tension was determined experimentally. Second, the coefficient of reduction of bolt axial force due to aging was calculated from the experimental results. Finally, a new bolt axial force reduction factor was calculated considering the above two experimental results and compared with the current bolt axial force reduction coefficient.

Ga‐doped zinc oxide (GZO) films are deposited on quartz substrates at ambient temperature via magnetron sputtering using a Zn‐added GZO powder target. The addition of Zn results in a significant increase in carrier density compared with that of the films deposited without adding Zn and a decrease in film resistivity to 4 × 10 −4 W cm. Additionally, it eliminates the in‐plane spatial distribution of the GZO‐film electrical properties; this distribution is observed when using a conventional sputtering target. Furthermore, the addition of Zn reduces the variation in the GZO‐film electrical properties with the T–S distance, exhibiting only a small increase in film resistivity at long T–S distances. The effect of adding Zn to a sputtering target indicates that the degradation in the GZO‐film electrical properties is mainly caused by the deficiency of Zn in the GZO crystals. The variation in GZO‐film thickness with the T–S distance shows an abrupt decrease in carrier density for small thicknesses, indicating the presence of acceptor‐like defects in the vicinity of the substrate/GZO interface; these defects cannot be eliminated by adding Zn.

Spectral measurements provide valuable information on the electronic states and crystal structures of materials. In particular, X-ray photoelectron spectroscopy (XPS) can facilitate the analysis of the chemical-bond states of the surfaces of materials. In the analysis of XPS spectra, the spectrum to be measured is typically compared to a reference spectrum measured from a known single-phase sample. Therefore, establishing a reference spectral database is imperative. In this study, round-robin tests (RRT) of XPS spectra are performed to obtain recommended XPS reference spectra and develop appropriate measurement conditions, including preprocessing procedures. Determining the variations in peak structures between equipment- and sample-derived spectral shapes and quantitatively discussing them through RRT of XPS spectra are challenging. Therefore, an analysis method that automatically determines the above-mentioned variations and extracts the sample-derived common spectral structures is developed in this study. This paper presents a new approach to the quantitative analysis of round-robin XPS spectral tests. The required common peak structure, a new definition of the XPS reference spectrum, is obtained. Further, a correlation between the variability of deviations in the spectral data of the RRT and the measurement condition and XPS measurement equipment used is determined. Such a framework is essential for standardizing XPS spectra and expanding the XPS reference spectral database.

In the maintenance of cable structures, such as cable-stayed bridges, cable safety is assessed based on the cable tension. In Japan, the cable tension is generally estimated from the cable’s natural frequencies using the higher-order vibration method. In recent years, dampers have been installed onto cables to suppress aerodynamic vibrations. Because the damper changes the cable’s natural frequencies, the damper is removed to measure the natural frequencies and estimate the cable tension without a damper, and the damper is then reinstalled. To avoid damper removal and reinstallation, the authors previously proposed Method 2F for estimating the tension of a cable with a damper from the natural frequencies without removing the damper. Because the tension estimation error of the higher-order vibration method for a cable without a damper has been reported as 5%, the authors set the target tension estimation error within 5%. However, the tension estimation error of Method 2F exceeded 5% in the experimental verification. Furthermore, although Method 2F estimates the tension and bending stiffness of the cable and the damper parameters simultaneously from the natural frequencies, the accuracy of the bending stiffness and damper parameters is unsatisfactory. In this paper, the new Method 2FM is proposed to estimate the tension and bending stiffness of the cable and damper parameters using the natural frequencies and two-point mode shapes. With the addition of mode shapes, Method 2FM attempts to improve the accuracy of estimating the tension and other parameters. The validity of Method 2FM was confirmed by numerical simulations and experiments. The numerical verification confirmed that Method 2FM is superior to Method 2F in estimating the cable tension and damper parameters. The experimental verification confirmed that the tension estimation accuracy of Method 2FM is higher than that of Method 2F, and the estimation error is lower than 5%. However, the damper parameters estimated by Method 2FM are different to the design values. The reason for this is the modeling error of the damper, as found by conducting an element test on the damper.

It is well known that liquid metal embrittlement (LME) cracking can occur during the resistance spot welding (RSW) of zinc-coated high-strength steels. These cracks can be classified into two types, based on location, namely outer cracks inside or outside the electrode indentation region, and inner cracks around the weld area. Recent research has proposed that the latter cracks can be inhibited by controlling weld schedules, though there have been a few reports concerning especially the effects of these cracks on joint properties. In this study, an X-ray CT scan and a tensile-shear test were carried out consecutively with 10 mm-wide RSW joints in order to visualize the cracks in 3 dimensions, and to clarify their effects on tensile-shear strength (TSS). The cracks in the RSW joints of the zinc-coated ultra-high strength steel could be clearly observed by the scan. The results showed that the TSS decreased to 40% by the small interface cracks even with the maximum depth of 170 μm.

Euglena gracilis, a type of microalgae, contains several nutrients and accumulates paramylon, a β-1,3-glucan. In recent studies, paramylon has shown to exhibit various activities including immunomoduratory and hepatoprotective effects. In the present study, using an in vitro cell culture system, we aimed to determine whether paramylon derived from the E. gracilis EOD-1 strain, which produces large amounts of paramylon, can augment SIRT1 expression in epidermal cells via activating gut–skin interactions. Results showed that paramylon augmented the expression of SIRT1 in Caco-2 cells, a human intestinal cell line. Furthermore, microarray analysis of Caco-2 cells treated with paramylon showed that paramylon activates epidermal cells through inducing the secretion of factors from intestinal cells. Then, we focused on skin cells as target cells of paramylon-activated intestinal cells. Results showed that secretory factors from Caco-2 cells treated with paramylon augmented the expression of SIRT1 in HaCaT cells, a human keratinocyte cell line, and that expression level of genes related to the growth and maintenance of epidermal cells were significantly changed in Caco-2 cells treated with paramylon as evidenced by microarray analysis. All these results suggest that paramylon can activate epidermal cells by inducing the production of secretory factors from intestinal cells.