CRITICAL COMPRESSIVE STRAIN OF LINEPIPES RELATED TO WORKHARDENING PARAMETERS

ABSTRACT An approximate solution to predict a critical compressive strain at the peak load (the peak load strain hereinafter) of linepipes subjected to axial compression is proposed in this paper. The approximate solution is derived from the deformation theory applying the stress-strain relationship with nonlinear hardening properties, which have not been taken into account in a number of current equations applied for pipeline design. The approximate solution proposed in this paper is a closed form equation, which is useful and effective for the practical application. The parameters in the Ramberg-Osgood representation expressing workhardenability of the linepipes are successfully introduced for the approximate solution. The effec-tiveness and accuracy of the approximate solution are verified comparing the critical compressive strains of several API 5L grade linepipes obtained by finite element analyses

EFFECT OF GEOMETRIC AND WELDING CONDITIONS ON THROUGH-THICKNESS RESIDUAL STRESS

ABSTRACT Recently, stress corrosion cracking (SCC) of core internals and/or recirculation pipes of austenite stainless steel (SUS316L) has been observed. SCC is considered to occur and progress at near the inner surface of the welding zone in buttwelded pipes, because of the tensile residual stress introduced by welding. In present work, three-dimensional and axisymmetric thermo-elastic-plastic finite element analysis have been carried out, in order to clarify the effect of geometric and welding conditions in circumferential welding zone on the residual stress. In particular, butt-welding joints of SUS316L-pipes have been examined. The residual stress was simulated by three-dimensional and axially symmetric models and the results were compared and discussed in detail

The seasonal variations of atmospheric 134,137Cs activity and possible host particles for their resuspension in the contaminated areas of Tsushima and Yamakiya, Fukushima, Japan

A large quantity of radionuclides was released by the Fukushima Daiichi Nuclear Power Plant accident in March 2011, and those deposited on ground and vegetation could return to the atmosphere through resuspension processes. Although the resuspension has been proposed to occur with wind blow, biomass burning, ecosystem activities, etc., the dominant process in contaminated areas of Fukushima is not fully understood. We have examined the resuspension process of radiocesium (134,137Cs) based on long-term measurements of the atmospheric concentration of radiocesium activity (the radiocesium concentration) at four sites in the contaminated areas of Fukushima as well as the aerosol characteristic observations by scanning electron microscopy (SEM) and the measurement of the biomass burning tracer, levoglucosan.The radiocesium concentrations at all sites showed a similar seasonal variation: low from winter to early spring and high from late spring to early autumn. In late spring, they showed positive peaks that coincided with the wind speed peaks. However, in summer and autumn, they were correlated positively with atmospheric temperature but negatively with wind speed. These results differed from previous studies based on data at urban sites. The difference of radiocesium concentrations at two sites, which are located within a 1 km range but have different degrees of surface contamination, was large from winter to late spring and small in summer and autumn, indicating that resuspension occurs locally and/or that atmospheric radiocesium was not well mixed in winter/spring, and it was opposite in summer/autumn. These results suggest that the resuspension processes and the host particles of the radiocesium resuspension changed seasonally. The SEM analyses showed that the dominant coarse particles in summer and autumn were organic ones, such as pollen, spores, and microorganisms. Biological activities in forest ecosystems can contribute considerably to the radiocesium resuspension in these seasons. During winter and spring, soil, mineral, and vegetation debris were predominant coarse particles in the atmosphere, and the radiocesium resuspension in these seasons can be attributed to the wind blow of these particles. Any proofs that biomass burning had a significant impact on atmospheric radiocesium were not found in the present study

Protocol for a Randomized, Crossover Trial : ISCHIA study

Objective: Intermittent-scanning continuous glucose monitoring (isCGM) is widely used in type 1 diabetes (T1D) patients; however, the education required to prevent hypoglycemia by using isCGM is not established. This study examines the combined effect of isCGM device usage and the education to reduce the time in hypoglycemia in comparison to conventional self-monitoring of blood glucose (SMBG). Methods: The Effect of Intermittent-Scanning Continuous Glucose Monitoring to Glycemic Control Including Hypoglycemia and Quality of Life of Patients with Type 1 Diabetes Mellitus Study (ISCHIA Study), a randomized, crossover trial, enrolls 104 T1D patients (age, 20-74 years) with T1D. Participants are randomized to use isCGM combined with structured education (Intervention period) or SMBG (Control period) for 84 days, followed by the other for a further 84 days. During the Intervention period, participants have access to the sensor glucose levels and trend arrow of the device. During the Control period, participants conduct SMBG at least three times a day, and retrospective CGM is used to record the blinded sensor glucose levels. The primary endpoint is the decrease of time in hypoglycemia ( < 70 mg/dL) per day (hour/day) during the Intervention period compared with the Control period. The secondary endpoints include other indices of glycemic control, glycoalbumin, accuracy of isCGM, diabetes-related quality of life (QOL), adherence, and cost-effectiveness. The study protocol has received Certified Review Board (CRB) approval from National Hospital Organization Osaka National Hospital (N2018002, February 14, 2019). This study is carried out in accordance with the Declaration of Helsinki and the Clinical Trials Act. The findings will be published in peer-reviewed journals. Conclusion: The ISCHIA study will contribute to the standardization of patient education regarding the prevention of hypoglycemia by using isCGM

メタカラコウ属植物の成分研究(第4報) : メタカラコウの根より単離された5, 6-Dimethoxy-2-isopropenylbenzofuranの化学的安定性

5, 6-Dimethoxy-2-isopropenylbenzofuran (1), which was isolated from the roots of Ligularia stenocephala MATSUM. et KOIDZ., was dissolved in MeOH and stand in a refrigerator for 5 days. The resultant mixture was shown to be composed of several products along with unchanged 1. Preparative HPLC of the mixture afforded eight compounds (2-9). Among them, compounds 2 and 3 were unstable and were found to change to compounds 4 - 11 during a few days in storage in the eluting solution of preparative HPLC [MeOH-H_20 (4 : 1)] at room temperature. The structures of compounds 2-11 were determined on the basis of spectral data

メタカラコウ属植物の成分研究(第2報)メタカラコウの葉及び根のトリテルペノイド成分について

Triterpenoids from the leaves and roots of Ligularia slenocephala MATSUM. et KOIDZ. (Compositae) have been investigated. Nine triterpenoids, squalene (1), cycloartanol (2), 24-methylenecycloartanol (3), dammara-20, 24-dien-3β-ol (4), 24-methylenedammar-20-en-3β-ol (5), α-amyrin (6), β-amyrin (7), 19α H-lupeol (8) and isoarborinol (9), have been isolated from the leaves of L. stenocephala. Three triterpenoids, butyrospermol (10), isobauerenol (11) and lupeol (12), have been isolated from the roots of L. stenocephala. Their structures were determined on the basis of spectral data