SIMULATION OF DELAYED BUSES IN A DUMPLING STATE AND ANALYSIS OF MAXIMUM WAITING TIME USING LOGISTIC REGRESSION

As cities become larger and societies become more complicated, the corresponding transportation systems also become more complicated. Thus far, many important transportation models have been investigated and applied to societies. In this work, we analyze a bus transportation model that includes high randomness. By strengthening the viewpoint of the users, the bunching of buses is further explored and considered as “the dumpling bus state,” referring to cases when the next scheduled buses closely run behind a delayed bus for a while. It is described that waiting people are split into winners (people with shorter waiting times) and losers (people with longer waiting times). Waiting time is also analyzed using logistic regression to obtain the probability of people who continue to wait

Magnetic thickness measurement for various iron steels using magnetic sensor and effect of electromagnetic characteristics

The diagnosis and prevention of the deterioration of iron-steel infrastructure has become an important social issue in recent years. The thickness measurement technique (extremely low-frequency eddy current testing (ELECT)) using a magnetic sensor for detecting steel corrosion at extreme frequency ranges has been previously reported. Using the calibration curves based on the correlation between the phase of the detected magnetic signal and the plate thickness, the plate thickness reduction caused by corrosion can be estimated from the detected phase signal. Iron-steel materials have large changes in electromagnetic characteristics; therefore, the reference calibration data for each type of iron-steel are required for plate thickness estimation. In this study, the effect of electromagnetic characteristics on the magnetic thickness measurement was investigated to improve the thickness estimation. Four types of iron-steel plates (SS400, SM400A, SM490A, and SMA400AW) with thicknesses ranging from 1 mm to 18 mm were measured by ELECT, and the phase change at multiple frequencies of each plate were analyzed. The shift in the phase and linearity regions of the calibration curves for each type of steel plate was observed. To analyze this shift phenomenon, the electromagnetic characteristics (permeability μ and conductivity σ) of each type of steel were measured. Compared with the permeability μ and conductivity σ of each steel plate in the applied magnetic field strength range, the product (σμ) for various steel plates decreased in the following order: SM400 > SS400 >SMA400AW > SM490A. The product of μ and σ is related to the skin depth, indicating the electromagnetic wave attenuation and eddy current phase shift in the material. Therefore, each shift in the calibration curve of each type of iron steel is explained by the changes in the parameters σ and μ

Thickness Measurement at High Lift-Off for Underwater Corroded Iron-Steel Structures Using a Magnetic Sensor Probe

Infrastructure facilities that were built approximately half a century ago have rapidly aged. Steel sheet piles, the inspection object in this study, are severely corroded, resulting in cave-in damages at wharfs. To solve such a problem, non-destructive inspection techniques are required. We previously demonstrated plate thickness measurement using extremely low-frequency eddy current testing. However, when the steel sheet piles are located in water, shellfish adhere to their surface, causing a lift-off of several tens of millimeters. Therefore, this large lift-off hinders the thickness measurement owing to fluctuations of magnetic signals. In this study, sensor probes with different coil diameters were prototyped and the optimum size for measuring steel sheet piles at high lift-off was investigated. Using the probes, the magnetic field was applied with a lift-off range from 0 to 80 mm, and the intensity and phase of the detected magnetic field were analyzed. Subsequently, by increasing the probe diameter, a good sensitivity was obtained for the thickness estimation with a lift-off of up to 60 mm. Moreover, these probes were used to measure the thickness of actual steel sheet piles, and measurements were successfully obtained at a high lift-off

Higher Blood Uric Acid in Female Humans and Mice as a Protective Factor against Pathophysiological Decline of Lung Function

The oxidant/antioxidant imbalance plays a pivotal role in the lung. Uric acid (UA), an endogenous antioxidant, is highly present in lung tissue, however, its impact on lung function under pathophysiological conditions remains unknown. In this work, pharmacological and genetic inhibition of UA metabolism in experimental mouse models of acute and chronic obstructive pulmonary disease (COPD) revealed that increased plasma UA levels improved emphysematous phenotype and lung dysfunction in accordance with reduced oxidative stress specifically in female but not in male mice, despite no impact of plasma UA induction on the pulmonary phenotypes in nondiseased mice. In vitro experiments determined that UA significantly suppressed hydrogen peroxide (H2O2)-induced oxidative stress in female donor-derived primary human bronchial epithelial (NHBE) cells in the absence of estrogen, implying that the benefit of UA is limited to the female airway in postmenopausal conditions. Consistently, our clinical observational analyses confirmed that higher blood UA levels, as well as the SLC2A9/GLUT9 rs11722228 T/T genotype, were associated with higher lung function in elderly human females. Together, our findings provide the first unique evidence that higher blood UA is a protective factor against the pathological decline of lung function in female mice, and possibly against aging-associated physiological decline in human females