Hitachi Zosen (Japan)

Efforts are made in this article to investigate the thermal and mechanical phenomena by presenting a coupled thermal and structural analysis of SA516 Grade-70 steel. This material has wide applicability in the fabrication of pressure vessels, boilers, etc., due to its excellent weldability and formability. An actual ongoing problem from a reputed industry, related to distortion during the shielded metal arc welding process, is considered and experiments are carried out on the chosen steel. Results are evaluated employing a two- step methodology, involving simulation. The first step encompasses thermal analysis, providing insights into transient temperature distribution, while the subsequent mechanical analysis offers data on residual stresses and distortion. In the case of heat input, a volumetric heat source with double ellipsoidal heat distribution is used whereas a plasticity material model with rate-independent bilinear kinematic hardening is adopted for the structural analysis. Additionally, temperature-dependent material properties are factored into both scenarios. The data derived from numerical analysis align closely with experimental findings, presenting valuable insights for fabricating industries.

Vortex rings are a promising method for mass transport. Experiments have confirmed that vortex rings derive energy from the downstream of the outlet of a device that combines a shock tube with an elliptical cell. This study aims to investigate the behavior of vortex rings and their circulation in detail. In the present study, the interference behavior of a supersonic jet and a vortex ring ejected from an elliptical cell installed downstream of a small-volume shock tube was numerically analyzed. As a result, the peak velocity of the jet flowing out of the cell exit increased with the circulation of the vortex ring. Furthermore, the center velocity of the vortex ring, which is the main factor contributing to the increased jet velocity, increases with the circulation. The center velocity of the vortex ring can be approximately predicted using a formula developed in this study. This result is essential for obtaining design principles for transport systems using vortex rings.

A male in his 80s was diagnosed with reflux esophagitis and Barrett's esophagus, and underwent endoscopy annually. After treatment for chronic pharyngeal mycosis, he developed scar stenosis at the esophageal orifice and regular follow-up was performed with a small-caliber endoscope. A depressed lesion was found in the esophagogastric junction (EGJ), and biopsy examination revealed adenocarcinoma (tub1). The preoperative diagnosis was Barrett's esophageal adenocarcinoma (depth, DMM-SM1). After endoscopic balloon dilatation, a therapeutic endoscope could be inserted and endoscopic submucosal dissection (ESD) was performed. Pathological examination revealed poorly differentiated adenocarcinoma, pT1b-SM2, ly1, v1, pHM0, pVM0. He desired no additional surgery. Five months later, lymph node and distant metastases developed.

This study reports the first experimental demonstration of surface contamination cleaning from a high-repetition supply of thin-tape targets for laser-driven carbon-ion acceleration. The adsorption of contaminants containing protons, mainly water vapor and hydrocarbons, on the surface of materials exposed to low vacuum (>10−3 Pa) suppresses carbon-ion acceleration. The newly developed contamination cleaner heats a 5-μm-thick nickel tape to over 400 °C in 100 ms by induction heating. In the future, this heating method could be scaled to laser-driven carbon-ion acceleration at rates beyond 10 Hz. The contaminant hydrogen is eliminated from the heated nickel surface, and a carbon source layer—derived from the contaminant carbon—is spontaneously formed by the catalytic effect of nickel. The species of ions accelerated from the nickel film heated to various temperatures have been observed experimentally. When the nickel film is heated beyond ∼150 °C, the proton signal considerably decreases, with a remarkable increase in the number and energy of carbon ions. The Langmuir adsorption model adequately explains the temperature dependence of desorption and re-adsorption of the adsorbed molecules on a heated target surface, and the temperature required for proton-free carbon-ion acceleration can be estimated.

We have developed a system that inspects the entire circumference of tube-totube sheet welds using phased array ultrasonic testing for manufacturing of heat exchangers. Therefore, a huge number of images were generated during the inspection. In the past, inspectors made visual judgments based on these images, but due to the long inspection period, it was difficult to inspect all of them. As a solution to this problem, we have developed a system that automatically detects flaws in weld. In constructing the flaw detection system, image processing, AE (Autoencoder), and CNN (Convolutional Neural Network) were examined, but individual judgment accuracy was not sufficient. Therefore, an ensemble method was applied. In the proposed method, the reliability of each discriminator was calculated for each image to be evaluated, and the presence or absence of flaws was finally determined according to the reliability. It was confirmed that the accuracy was improved by applying this flaw detection system.

In an incineration plant, remote operation from a centralized control room is now possible, but inspection and cleaning of equipment still require a worker to visit the site. When the plant owner reduces the number of workers due to operation costs, it will be standard for a single worker to visit the site. Therefore, it is necessary to monitor the location of workers in real-time to detect unexpected human accidents quickly. Conventional methods use radio waves, such as Wi-Fi and Bluetooth, but there is little demand for communication equipment in the incineration plant. However, there is not enough demand for communication facilities in the incineration plant. It is too large to bear the cost of installing wireless access points, and Bluetooth Low Energy (BLE) beacons just for positioning. Therefore, we are focusing on magnetism using for indoor positioning method. In addition, the incineration plant has a lot of types of equipment that contains a wide range of magnetized metals, large motors, and generators. We could observe the magnetic peculiarity at each point. Based on these assumptions, we have developed a new indoor positioning method at the incineration plant. This paper describes the development of an indoor positioning system for an incineration plant. And we propose three methods for fingerprinting matching: Point matching, Path matching, and DTW matching. The average positioning errors of these methods are 6.89 m, 0.05 m, and 0.06 m, respectively.