Internal Stress in Electrodeposited Metals

This paper is concerned with the mechanism responsible for the internal stress in the electrodeposited metals. Metals such as nickel, chromium, copper, etc., exhibit tensile stress during their electrodeposition, whereas zinc and cadmium show compressive stress. When the electrodeposited metals are kept in air by removal from their electrolytes after electrodeposition, they release a certain amount of hydrogen and the stress in them becomes more tensile. When hydrogen is electrodeposited on the surface of electrodeposited metals and hydrogen occlusion takes place in the electrodeposits, stress in metals is changed to compressive. From the results obtained, the authors have arrived at a conclusion that one of the factors responsible for creating internal stress in the electrodeposited metals is the release or introduction of hydrogen in the electrodeposited metals

A New Criterion for the Strength of Metals under Combined Alternating Stresses

Matsumura's theory of malleable materials, stating that “the elastic failure occurs in malleable materials when the maximum shear stress reaches a definite value depending on shear strain energy” is fairly well applicable to results of experiments, so far as the material is ductile; but the theory is not applicable to brittle materials. Extending Matsumura's theory to all materials, ductile and brittle, the authors propose now a new criterion and applying it to the case of fatigue, they think that “the fatigue failure occurs in ductile materials when the greatest maximum shear stress induced by combined repeated stresses reaches a definite value depending on shear strain energy at the instant, and that the fatigue occurs in brittle materials when the greatest maximum principal stress induced by the combined repeated stresses reaches a definite value depending also on shear strain energy at the instant.”From this new criterion on fatigue, they derive the conditions of fatigue failure under the combination of various stresses. Comparing the results of calculation with those of experiments, it is established that the new criterion is fairly well applicable to results of experiments in every case

The Strength of Metals under Combined Alternating Bending and Torsion

Fatigue tests under combined bending and torsion were carried out for several ferreous and nonferreous metals with a testing machine specially designed. As the results of tests, strength of metals under combined alternating bending and torsion were expressed by a simple relation, using fatigue strength of each metals under simple bending and torsion. And some considerations about fatigue fracture were made

The Strength of Metals under Combined Alternating Bending and Torsion with Phase Difference

A new fatigue testing machine capable of making experiments under combined alternating bending and torsion with any phase difference has been devised and proved to be satisfactory in operation by the authors. From the test results obtained by experiments carried out on some metals with the machine, the effect of phase difference on the strength of the metals under combined bending and torsion has been made clear

Studies on Fatigue of Mild Steel by a Corrosion Method

The fatigued zone in mild steel can be detected by a corrosion method as well as when yielded parts are shown as a strain figure. By the corrosion method, the authors have studied the appearances of the fatigued zone and fatigue crack in each specimen at progressive stages of fatigue. Consideration has also been made of the mechanism of fatigue failure with specimens having a smooth surface and having various notches

Internal Stress in Electrodeposited PbO₂

The change of internal stress in the electrodeposited PbC₂ from a lead nitrate bath was observed by measuring the deflection of a thin platinum anode during electrodeposition of PbC₂ on one side of it. The crystal structure of the deposits was determined by X-ray diffraction. After the electrodeposition, the change of deflection of the deposited Pb₂ was observed under the following conditions : a) Keep the deposited PbO₂ in air or in a lead nitrate bath at constant temperatures. b) Discharge the cell, Pt/PbNO₃ electrolyte/PbO₂ deposit, by connecting it to an external circuit with some resistance. The results obtained are summarized as follows : 1) The crystal structure of α-PbO₂ was observed in the deposits which had deflected in the direction of contraction during electrodeposition, and β-PbO₂ was observed in the deposits which had deflected in the direction of expansion during electrodeposition. 2) After the electrodeposition, the deposits deflected gradually in the direction of expansion when they were kept in air or left in the bath. The amount of deflection of the deposits of α-PbO₂ was larger than that of the deposits of β-PbO₂ within the same time duration. 3) The electrodeposited PbO₂ deflected in the direction of expansion by discharging the cell, and the amount of deflection of the deposits of α-PbO₂ was larger than that of the deposits of β-PbO₂

Potential oxygen consumption and community composition of sediment bacteria in a seasonally hypoxic enclosed bay

The dynamics of potential oxygen consumption at the sediment surface in a seasonally hypoxic bay were monitored monthly by applying a tetrazolium dye (2-(4-iodophenyl)-3-(4-nitrophenyl)-5-phenyl-2H-tetrazolium chloride [INT]) reduction assay to intact sediment core samples for two consecutive years (2012–2013). Based on the empirically determined correlation between INT reduction (INT-formazan formation) and actual oxygen consumption of sediment samples, we inferred the relative contribution of biological and non-biological (chemical) processes to the potential whole oxygen consumption in the collected sediment samples. It was demonstrated that both potentials consistently increased and reached a maximum during summer hypoxia in each year. For samples collected in 2012, amplicon sequence variants (ASVs) of the bacterial 16S rRNA genes derived from the sediment surface revealed a sharp increase in the relative abundance of sulfate reducing bacteria toward hypoxia. In addition, a notable shift in other bacterial compositions was observed before and after the INT assay incubation. It was Arcobacter (Arcobacteraceae, Campylobacteria), a putative sulfur-oxidizing bacterial genus, that increased markedly during the assay period in the summer samples. These findings have implications not only for members of Delta- and Gammaproteobacteria that are consistently responsible for the consumption of dissolved oxygen (DO) year-round in the sediment, but also for those that might grow rapidly in response to episodic DO supply on the sediment surface during midst of seasonal hypoxia

A Case of Ductal Dysplasia of the Pancreas A Possible Prerequisite for Pancreatic Cancer

The precise pathobiology of precursor lesions, which develop into pancreatic adenocarcinoma, remains controversial. Recently, we encountered a patient with dysplastic lesion of the pancreas; a case in which a precursor lesion of the pancreatic carcinoma may have been documented. The patient was a 73-year-old female with epigastric discomfort. As part of a general check-up, she underwent abdominal ultrasound, which revealed the pancreatic duct in the pancreatic body to be slightly indented. Computed tomography (CT) scan revealed mild dilatation of the main pancreatic duct and a small low-density area (less than 1 cm in diameter). Endoscopic retrograde cholangiopancreatography (ERCP) showed the irregularity in the body of the main pancreatic duct. Under general anesthesia, resection of the distal portion of the pancreas was performed with splenic conservation. Pathological examination revealed focal hyperplastic epithelium of the pancreatic duct with moderate dysplasia. Expression of the proliferating cell nuclear antigen (PCNA) in the lesion was observed, indicating a slightly proliferative nature. Mutant p53 protein was slightly expressed in the lesion. As is seen in this case, ductal hyperplasia of the pancreas might represent precursor lesions, and constitute part of a continuous development spectrum evolving into ductal adenocarcinoma of the pancreas with accumulation of genetic alterations

A machine learning model for predicting the lymph node metastasis of early gastric cancer not meeting the endoscopic curability criteria

The version of record of this article, first published in Gastric Cancer, is available online at Publisher’s website: https://doi.org/10.1007/s10120-024-01511-8.Background: We developed a machine learning (ML) model to predict the risk of lymph node metastasis (LNM) in patients with early gastric cancer (EGC) who did not meet the existing Japanese endoscopic curability criteria and compared its performance with that of the most common clinical risk scoring system, the eCura system. Methods: We used data from 4,042 consecutive patients with EGC from 21 institutions who underwent endoscopic submucosal dissection (ESD) and/or surgery between 2010 and 2021. All resected EGCs were histologically confirmed not to satisfy the current Japanese endoscopic curability criteria. Of all patients, 3,506 constituted the training cohort to develop the neural network-based ML model, and 536 constituted the validation cohort. The performance of our ML model, as measured by the area under the receiver operating characteristic curve (AUC), was compared with that of the eCura system in the validation cohort. Results: LNM rates were 14% (503/3,506) and 7% (39/536) in the training and validation cohorts, respectively. The ML model identified patients with LNM with an AUC of 0.83 (95% confidence interval, 0.76–0.89) in the validation cohort, while the eCura system identified patients with LNM with an AUC of 0.77 (95% confidence interval, 0.70–0.85) (P = 0.006, DeLong’s test). Conclusions: Our ML model performed better than the eCura system for predicting LNM risk in patients with EGC who did not meet the existing Japanese endoscopic curability criteria. Mini-abstract: We developed a neural network-based machine learning model that predicts the risk of lymph node metastasis in patients with early gastric cancer who did not meet the endoscopic curability criteria