Prediction of long-term creep deflection of seismic isolation bearings

Isolation structures use high damping rubber bearings (HDRBs), lead rubber bearings (LRBs), and natural rubber bearings (NRBs) in order to significantly reduce the seismic forces transmitted from a substructure to a superstructure. The laminated rubber bearing is the most important structural member of a seismic isolation system. We present an analysis of a 1000 hr ongoing creep test conducted at 7.5 and 8.37 MPa in our laboratory. The long term behavior of bridge bearings (e.g., laminated rubber bearings) is determined through compression creep tests subjected to actual environmental conditions. These tests indicate that the maximum creep deformation is about 0.3 to 1.92 % of the total rubber thickness

Exercise training-induced PPARβ increases PGC-1α protein stability and improves insulin-induced glucose uptake in rodent muscles

This study aimed to investigate the long-term effects of training intervention and resting on protein expression and stability of peroxisome proliferator-activated receptor β/δ (PPARβ), peroxisome proliferator-activated receptor gamma coactivator 1-α (PGC1α), glucose transporter type 4 (GLUT4), and mitochondrial proteins, and determine whether glucose homeostasis can be regulated through stable expression of these proteins after training. Rats swam daily for 3, 6, 9, 14, or 28 days, and then allowed to rest for 5 days post-training. Protein and mRNA levels were measured in the skeletal muscles of these rats. PPARβ was overexpressed and knocked down in myotubes in the skeletal muscle to investigate the effects of swimming training on various signaling cascades of PGC-1α transcription, insulin signaling, and glucose uptake. Exercise training (Ext) upregulated PPARβ, PGC-1α, GLUT4, and mitochondrial enzymes, including NADH-ubiquinone oxidoreductase (NUO), cytochrome c oxidase subunit I (COX1), citrate synthase (CS), and cytochrome c (Cyto C) in a time-dependent manner and promoted the protein stability of PPARβ, PGC-1α, GLUT4, NUO, CS, and Cyto C, such that they were significantly upregulated 5 days after training cessation. PPARβ overexpression increased the PGC-1α protein levels post-translation and improved insulin-induced signaling responsiveness and glucose uptake. The present results indicate that Ext promotes the protein stability of key mitochondria enzymes GLUT4, PGC-1α, and PPARβ even after Ext cessation

Sociodemographic factors associated with the use of mental health services in depressed adults: results from the Korea National Health and Nutrition Examination Survey (KNHANES)

Background: The aims of this study were to determine the utilization of mental health services (MHSs) by adults with a depressive mood and to identify the influencing sociodemographic factors, using a nationwide representative Korean sample. Methods: The study included 2735 subjects, aged 19 years or older, who had experienced a depressive mood continuously for over 2 weeks within the previous year, using the data from the KNHANES IV (Fourth Korea National Health and Nutrition Examination Survey), which was performed between 2007 and 2009, and involved a nationally representative sample of the Korean community population who were visited at home. A multivariate logistic regression analysis was used to estimate the adjusted odd ratios (ORs) and 95% confidence intervals (CIs) for the use of MHSs, which was defined as using healthcare institutions, consulting services, and inpatient or outpatient treatments due to mental health problems. Results: MHSs had been used by 9.6% of the subjects with a depressive mood. The use of the MHSs was significantly associated with age, education level, and employment status, after adjusting for sociodemographic and health-related factors. Specifically, the OR for the nonuse of MHSs by the elderly (≥65 years) relative to subjects aged 19–34 years was 2.55 (95% CI = 1.13–5.76), subjects with a lower education level were less likely to use MHSs compared to those with a higher education level (7–9 years, OR = 2.35, 95% CI = 1.19–4.64; 10–12 years, OR = 1.66, 95% CI = 1.07–2.56; ≥13 years, reference), and the OR of unemployed relative to employed was 0.47 (95% CI = 0.32–0.67). Conclusions: Among Korean adults with a depressive mood, the elderly, those with a lower education level, and the employed are less likely to use MHSs. These findings suggest that mental health policies should be made based on the characteristics of the population in order to reduce untreated patients with depression. Greater resources and attention to identifying and treating depression in older, less educated, and employed adults are warranted

USCID fourth international conference

Presented at the Role of irrigation and drainage in a sustainable future: USCID fourth international conference on irrigation and drainage on October 3-6, 2007 in Sacramento, California.Includes bibliographical references.Since 3000 BC, rice has been the main crop in the Korean Peninsula, and where currently most of the available irrigation water is used to grow paddy rice. Methods for calculating the quantity of irrigation water required developed in the 1990's were compared to quantities measured in the field. The largest difference between calculated and measured quantities occurred in April and May. Based on field data we obtained in the middle part of the Korean Peninsula, significant changes have occurred in rice management, which has changed the amount of irrigation water required. Rice is now transplanted earlier, and duration of the transplanting phase on the regional scale is shorter through mechanization and consolidation of land holdings. These changes need to be taken into account when calculating the quantity of water needed for irrigation

Mechanical behavior of seismic isolation bearings in earthquake-induced ultimate limit state

High-damping rubber bearings, lead rubber bearings, and natural rubber bearings are often used to improve the seismic capacity of seismic isolation bearings. We present the results of an extensive series of experimental tests to identify the mechanical characteristics of these three types of seismic isolation bearings. Cyclic horizontal displacement tests, varying the test parameters of shear displacement amplitude axial load, and loading frequency tests were performed on each type of bearing. Bearing shear stiffness and damping properties were investigated in terms of the different test parameters. The ultimate tests consisted of monotonic shear loading to failure under axial loads, and tension failure tests of the bearings with bolted connections. Comparisons are made between experimental results and available analytical relationships for material and bearing properties

A study on the characteristics of bridge bearings behavior by finite element analysis and model test

The increased vibration level of the railway bridge could make significant noise and, also, cause structural damages such as fatigue cracks. Related to these subjects, a spherical elastomeric bridge bearing, which is layered by hemispherical rubber and steel plates, was investigated in terms of its vibration performance. Several different shape factors could be considered by changing the curvature of hemispherical surface and size in rubber and steel plate thicknesses in the manufacturing stage. The performance of the spherical elastomeric bearing for the reduction in vibration was compared with that of the conventional bearing by performing vibration experiments on a scale-downed model. The rubber material characteristics and spherical shape are found to be important parameters in reducing the bridge vibration