Soundness evaluation of slopes along national roads using Self-organizing Maps

In the conventional way of soundness evaluation by Ministry of Land, Infrastructure and Transport (MLIT), Japan, the soundness of road slopes has been evaluated using regular inspection table. However, it has been reported that slope failures occurred in many road slopes which had been judged as “sound”. In this study, therefore, Kohonen’ s Self-Organizing Maps (SOM) was applied to evaluate the soundness of slopes along national roads. The SOM is eff ective tool for clustering and visualizing complex high-dimensional data on a single low-dimensional map, saving information among original data without any external criteria. The objective of this study is to extract unstable road slopes whose features are similar to the ones collapsed in the past using SOM

Study on the plain concrete piers for railway and their damage caused by earthquakes

Plain concrete piers mainly constructed from the Taisho to early Showa era instead of masonry piers and have been used. Since the resistance of plain concrete piers to earthquakes is weaker than the reinforced concrete piers constructed after 1955, serious damage caused by earthquakes is observed in some plain concrete piers. Therefore, in this study, we investigated the current conditions of plain concrete piers for railway bridge and their damage caused by earthquake to obtain the fundamental data for further development of the effective countermeasure of plain concrete piers without increasing the cross section.　According to the investigation of current situation and damage caused by earthquakes, the plain concrete piers were seriously damaged by even earthquakes with small seismic intensity. This may be caused by the fact that the criteria for seismic design of railway piers was not established before 1930. In addition, some slides occurs along the construction joint of concrete in the direction perpendicular to the railway track and serious damage was observed in the lower part of the construction joints. In the future, a series of shaking table tests using large scale replica of plain concrete pier and their numerical simulations are planed in order to clarify the damage mechanism of the plain concrete piers during earthquakes

Damage Situation of Stone Walls in Kumamoto Castle Caused by the 2016 Kumamoto Earthquake

The authors investigated the damage situation of masonry structures caused by the 2016 Kumamoto earthquake. In this paper, the damage situation of stone walls in Kumamoto castle is reported and the mechanisms of failure and collapse of stones are discussed. The 3-D laser scanner was also applied to obtain the 3D geometry and the displacement/deformation of the stone walls was analyzed by comparing with the previous measurement results before the earthquake. The 3D laser scanning results clearly show the unnatural shape of the stone walls caused by the movement of the backfill. This unnatural shape of the stone walls can be observed even in the stone walls which avoid the collapse. In the future, the evaluation of the safety/stability of the masonry walls is important for the restoration and 3D digital data obtained by 3D laser scanning technique will be useful.研究ノー

Hyperoxemia and excess oxygen use in early acute respiratory distress syndrome : Insights from the LUNG SAFE study

Publisher Copyright: © 2020 The Author(s). Copyright: Copyright 2020 Elsevier B.V., All rights reserved.Background: Concerns exist regarding the prevalence and impact of unnecessary oxygen use in patients with acute respiratory distress syndrome (ARDS). We examined this issue in patients with ARDS enrolled in the Large observational study to UNderstand the Global impact of Severe Acute respiratory FailurE (LUNG SAFE) study. Methods: In this secondary analysis of the LUNG SAFE study, we wished to determine the prevalence and the outcomes associated with hyperoxemia on day 1, sustained hyperoxemia, and excessive oxygen use in patients with early ARDS. Patients who fulfilled criteria of ARDS on day 1 and day 2 of acute hypoxemic respiratory failure were categorized based on the presence of hyperoxemia (PaO2 > 100 mmHg) on day 1, sustained (i.e., present on day 1 and day 2) hyperoxemia, or excessive oxygen use (FIO2 ≥ 0.60 during hyperoxemia). Results: Of 2005 patients that met the inclusion criteria, 131 (6.5%) were hypoxemic (PaO2 < 55 mmHg), 607 (30%) had hyperoxemia on day 1, and 250 (12%) had sustained hyperoxemia. Excess FIO2 use occurred in 400 (66%) out of 607 patients with hyperoxemia. Excess FIO2 use decreased from day 1 to day 2 of ARDS, with most hyperoxemic patients on day 2 receiving relatively low FIO2. Multivariate analyses found no independent relationship between day 1 hyperoxemia, sustained hyperoxemia, or excess FIO2 use and adverse clinical outcomes. Mortality was 42% in patients with excess FIO2 use, compared to 39% in a propensity-matched sample of normoxemic (PaO2 55-100 mmHg) patients (P = 0.47). Conclusions: Hyperoxemia and excess oxygen use are both prevalent in early ARDS but are most often non-sustained. No relationship was found between hyperoxemia or excessive oxygen use and patient outcome in this cohort. Trial registration: LUNG-SAFE is registered with ClinicalTrials.gov, NCT02010073publishersversionPeer reviewe

Distinct element analysis for Class II behavior of rocks under uniaxial compression

In this study, the radial strain control method for uniaxial compression tests was introduced in the distinct element method (DEM) codes and the Class II behavior of rocks was simulated. The microscopic parameters used in the DEM models were determined based on laboratory uniaxial compression tests and Brazilian tests carried at Äspö Hard Rock Laboratory, Sweden. The numerical simulation results show good agreement with the complete stress–strain curves for Class II obtained from the laboratory experiments. These results suggest that the DEM can reproduce the Class II behavior of the rock successfully. The mechanism of the Class II behavior was also discussed in detail from the microscopic point of view. The loading condition and microscopic structure of rocks will play an important role for the Class II behavior