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Friction stir processing (FSP) effectively improves the fatigue strength of arc-welded joints; however, wear of tools is inevitable in case of high-strength materials. Notably, a new benefit has been discovered: compressive residual stress is applied on the FSPed steel surface, alloyed with the WC tool constituent elements, contrasting with the tensile residual stress typically applied via conventional FSP. To elucidate the mechanism of compressive residual stress application, FSP was performed on a low-carbon steel plate at various rotational speeds. The alloyed topmost layers in the stir zone comprised martensite structures with a small amount of retained austenite grains, resulting in a hardness increase owing to the tool constituent elements. The residual stresses on the stir zone surface were influenced by the alloying contents and the corresponding martensite start temperature (Ms). Compressive residual stresses were maximized at an Ms of approximately 150 °C owing to martensitic transformation expansion near room temperature. Lowering the Ms below approximately 150 °C led to tensile residual stresses and an increased volume fraction of the retained austenite, suggesting that martensitic transformation expansion is insufficient to apply compressive residual stress. Conversely, the retained austenite can resist plastic deformation and crack propagation through deformation-induced martensitic transformation, thereby enhancing fatigue properties.

Due to the increasing burden on the traditional control systems, inverter-based resources (IBR) is required to take part in grid stability efforts. This is the key to increasing the share of IBRs in the power grid and ensuring that issues related to reduced inertia are handled properly. There have been some efforts towards developing frequency control for smart inverters such as frequency–watt​ mode. However, a fully functioning synthetic inertia mode combined with a smart inverter has not been developed yet. In this paper, a novel function is developed for implementing synthetic inertia in smart inverters as a combination of several control modes. Then, the operating curves of these control modes are varied to investigate their impact on the synthetic inertia’s performance and stability. These operations are tested both with lab equipment and controller hardware in the loop (CHIL) testing to study the accuracy of the latter. Once accuracy is established, further CHIL tests have been performed to investigate the interaction between the developed synthetic inertia function and other smart inverter functions such as Volt-Var Control. Results show that there is no negative impact on either of the functions and they can be safely activated simultaneously.

The increasing share of renewable energy-based resources in the power grid has a detrimental impact on the power system stability. As these resources are inverter-based, they decrease the overall inertia of the grid. To mitigate this problem, recent research focuses on developing novel techniques to provide synthetic inertia with inverters. In this fashion, inverter-based resources (IBR) can also contribute to power system inertia, hence, its stability. Some of the approaches for providing synthetic inertia are discussed in the standards. However, despite its potential, frequency-derivate-based (df/dt) solutions are not studied to adapt grid code in Japan. This paper addresses this need by developing a full df/dt control approach for IBRs. Several intricacies of this design is presented along with operation curves and system designs. Considering the special needs of the Japanese Electrical Grid, and the speed in which inertia support should be provided, a novel rate of change of frequency (RoCoF) measurement approach is also developed and presented. Lab tests are performed with hardware-in-the-loop tests and the results validate the operation and performance of both novel RoCoF measurement and df/dt control model.

Summary: Here, we provide a step-by-step protocol to measure the activities of multiple transcription factors (TFs) in the same mouse brain. This protocol includes a procedure to construct a virus-based TF activity reporter, in utero transfection, and PCR-based measurement of TF activity to obtain the transcription factor activity profile (TFAP). Our protocol facilitates a systematic analysis of TF activity of the brain in vivo and will aid trans-omics understanding of the molecular mechanism underlying the brain functions.For complete details on the use and execution of this protocol, please refer to Abe and Abe, (2022). : Publisher’s note: Undertaking any experimental protocol requires adherence to local institutional guidelines for laboratory safety and ethics.

Electronic states in solid-solution transition metal oxides may differ from those in their parent compounds, and this results in interesting electronic properties. In this study, the valence states and electronic properties of solid solutions of (1 − x)PbVO3− xBiCrO3 are reported. The solid solutions are successfully synthesized under high-pressure and high-temperature conditions of 5 GPa or 7 GPa and 1273 K, respectively. A change in the crystal structure from centrosymmetric monoclinic (C2/c), as in BiCrO3, to polar tetragonal (P4mm), as in PbVO3, is observed. A tetragonal-to-cubic phase transition, which results in a negative thermal expansion, was observed in 7/8PbVO3-1/8BiCrO3 at approximately 700 K. X-ray absorption spectroscopy and magnetic studies reveal that the Cr and V atoms are in the valence states 3+ and 4+, respectively, which are the same as those of the parent compounds. Thus, it was concluded that the valence state of V4+/Cr3+ and the electron localization in the (1 − x)PbVO3− xBiCrO3 solid solutions are considerably robust.

Fatigue strength of fusion-welded joints is lower than that of the base metal due to stress concentration, tensile residual stress, and microstructural degradation at the weld toe. To improve these issues, friction stir processing (FSP) using a spherical tip tool was directly applied to the weld toe of high-strength low-alloy steel joints. The toe geometry was successfully modified without defect formation, resulting in 25% reduction in fatigue notch factor in comparison to the as-welded joints. Significant grain refinement due to FSP increased hardness beneath the toe surface. In addition, compressive residual stress related to tool wear was produced on the FSP surface. Bending fatigue strength was improved by these benefits, with dependence on the tool travel speed. Fatigue crack initiation occurred at the toe surface for all the joints. Although high travel speed FSP produced serrated surface resulting in degradation of FSP improvement in fatigue strength, low travel speed FSP contributed to reduction of surface roughness leading to maximum FSP improvement of 50% in fatigue strength. The results obtained in this study suggest the encouraging prospect of direct application of FSP to weld toes as new post-weld treatment for steel joints. Keywords: Friction stir processing, Post-weld treatment, High-strength low-alloy steel, Fatigue strength, Weld geometry, Residual stress

This study aimed to obtain a W/Cu clad with high bending strength using explosive welding (EW), since its thermo-physical property combination is attractive for industrial applications. Cladding both metal plates using EW results cracks in W plates from the surface toward interface. Eliminating the cracks in W plate of clads was a major challenge in this study. The formation of cracks is fundamentally due to generation of high-intensity reflected tensile waves as a consequence of the undissipated imparted kinetic energy (KE) at the collision interface. A crack-free W plate as well as higher bending strength have been obtained in the W/Cu clads produced at the highest collision velocity with lower collision angles among three samples produced at different horizontal collision velocities. The EW clad interface exhibited an intermediate layer (IL), which was associated with higher consumption of KE at the interface, leading to reduction of the intensity of reflected tensile waves. The IL consisted of nanometer- and submicrometer-sized W fragments distributed in a Cu matrix, leading to higher hardness than a Cu plate. This could have contributed to the increase in the bending strength of the clads. (187 words).

A systematic, comparative study was carried out to quantitatively characterize the bending strength of wavy interfaces with and without an intermediate layer (IL) in Nb/Cu and Ta/Cu explosive clads. The clads having wavy interfaces with and without an IL were obtained at horizontal high and low collision velocities (HCV and LCV) in the explosive welding, respectively. The stress-strain curves of all the clads were similar in three-point bending tests, but the clads with an IL exhibited higher bending stress than those without an IL. Moreover, cracks were observed in the Nb plate of Nb/Cu clads without an IL, but no cracks in that with an IL. TEM observation confirmed coexistence of ultrafine refractory metal and Cu phases in the ILs. In addition, the Ta-Cu-based intermetallic compound or dodecagonal quasicrystal, which is a non-equilibrium phase, were also observed along with coexistence of Ta and Cu phases in the ILs of Ta/Cu interface. Cladding at HCV and a lower collision angle assisted in resultant less strain in refractory metal plates near the joint interfaces than those at LCV, due to IL formation. The ILs assisted in obtainment of interfaces of higher hardness, leading to higher bending-stress clads without losing large elongation. Keywords: Explosive welding, Wavy interface, Intermediate layer, Ultra-fine scale coexistence, Non-equilibrium intermetallic compound, Quasicrystal

Increased caloric intake and Westernized dietary choices may be contributing toward a recent rising trend of incidences of chronic lifestyle-related diseases. In this study, we evaluated the anticancer properties of Plant Enzyme Validux (PEV) using a mouse model. Five-week-old male C3H mice were randomly distributed into four experimental groups: Control, PEV only, 6Gy irradiation only, and PEV + 6Gy. PEV was orally administered daily at 500 mg/kg for 14 days prior to three rounds of 2Gy irradiation. We focused on the anticancer action and immunostimulatory effects of PEV with and without irradiation. Oncogene suppression was observed after PEV treatment as was an increase in TNF-α, suggesting an antitumor effect. PEV administration also appeared to reduce oxidative stress as evidenced by a decrease in lipid peroxidation. In addition, PEV confirmed radioprotective effect by radical blocking ability by radiation irradiation. Immunological responses to PEV administration were evidenced by an increase in number of total white blood cells and T lymphocytes. Immunotherapy is drawing more and more attention as a treatment for prostate cancer, suggesting that there will be a need for the identification of specific targets for prostate cancer and for more basic research on the genetic aspects of immunotherapy. Thus, PEV may be of use as a radioprotective supplement during radiotherapy for tumor treatment.

The shock wave damage during explosive welding has not been reported in a flyer Mo plate of the Mo/Cu clads. However, it would be an inevitable problem in group VI elements. This study was aimed to characterize the shock wave damage in the Mo plate, that is less brittle than a W plate, of explosive welded Mo/Cu clads. Cladding at low horizontal collision velocities leading to high collision angles was expected to enhance the shock wave damage, and the clads resulted in less elongation in bending tests. On the other hand, in the clads obtained at high horizontal collision velocities (HCVs) with low collision angles, their bending elongation increased significantly. The shock wave damage penetrated from the surface of a Mo plate to the Mo/Cu interface, and thus reducing thickness of a Mo plate of bending specimens increased bending plastic strain. The shock wave damage is associated with kinetic energy imparted to the flyer Mo plate, and thus loss of kinetic energy due to formation of an intermediate layer at the interface and reducing thickness of a flyer Mo plate would be very helpful for decrease of shock wave damage.

Tandem-pulsed gas metal arc welding (TP-GMAW) simultaneously uses two wire-electrodes to enhance the material deposition rate, leading to the generation of a finger-shaped penetration as one of the arcs penetrates deeper than the other. On the other hand, workpiece vibration is one of the techniques used to control the microstructure of weld metal and a heat-affected zone. It is incidentally found that a specific vibration condition changes the finger-shaped penetration into pan-bottom shaped penetration in the TP-GMAW even though the vibration energy is much lower than the arc energy. Microstructure observation and elemental analysis are carried out for the welds fabricated without vibration and with three kinds of vibration modes, namely sine, random, and shock. The specific sine-mode vibration exhibits pan-bottom. The other modes of vibration in the same welding conditions exhibited invariable finger-shaped penetration. The Si atoms as a tracer distribute uniformly in the sine-mode. However, Si atoms segregate at the bottom of the finger-shaped weld metal with the random-mode and shock-mode workpiece vibrations. The weld pool shape change is prominent at a specific frequency. A resonance phenomenon between the droplet flow pattern and the molten material flow in the weld pool is likely to play a vital role in the change.

We demonstrated the lattice structures and the superconducting phases of metallic double-chain based cuprate Pr2Ba4- Cu7O15-d exhibiting higher Tc. After the oxygen heat treatment on citrate pyrolysis precursors, their reduction treatment followed by a quench procedure caused higher Tc samples with 26.5-30 K. The crystal structural parameters for the superconducting sample (d = 0.81) were analyzed from the powder synchrotron X-ray diffraction data using RIETANFP program. The effect of magnetic field on the superconducting phase of these samples with different oxygen defects (d = 0.73, 0.81, and 0.87) was examined, for our understanding of the superconducting magnetic field-temperature phase diagram. For the d = 0.87 sample with Tc ~ 30 K, the resistive critical field H-c was estimated to be 13 T at 4.2 K. The oxygen deficiency dependence on Tc,on for our samples was compared with the data of several other groups. [ABSTRACT FROM AUTHOR]

Chemical substitution is an effective way to improve electrocatalytic properties in transition metal oxides. We investigate the synergistic effect between Fe4+ and Co4+ ions on the catalytic activity for oxygen evolution reaction (OER) in the Fe–Co-mixed perovskite oxide CaFe1−xCoxO3. The OER activity of CaFe1−xCoxO3 is substantially increased by small amounts of Co (Fe) doping into CaFeO3 (CaCoO3), leading to the superiority compared to the pure Fe and Co perovskite oxides. The x dependences of the OER overpotential and specific activity for CaFe1−xCoxO3 (0.05 ≦ x ≦ 0.95) are expressed by constant offset from the weighted average between CaFeO3 and CaCoO3, which can be interpreted to be the synergistic effect between Fe4+ and Co4+ ions on OER activity. The absence of the optimum x for the highest activity for CaFe1−xCoxO3 contrasts with the volcano-like plots reported in various mixed-metal oxides. First-principle calculations using the special quasirandom structure models on CaFe1−xCoxO3 (x = 0.03–0.5) demonstrate that about half the amount of Fe4+ is electronically activated to possess smaller charge-transfer energies, corroborating the enhancement of catalytic activity in CaFe1−xCoxO3. These findings provide new insight into the synergistic effects in complex transition metal oxide catalysts. [ABSTRACT FROM AUTHOR]