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

Comparison of the Plasma Metabolome Profiles Between the Internal Thoracic Artery and Ascending Aorta in Patients Undergoing Coronary Artery Bypass Graft Surgery Using Gas Chromatography Time-of-Flight Mass Spectrometry.

BackgroundThe left internal thoracic artery (LITA) has been used as the first conduit of choice in coronary artery bypass grafting (CABG) because of excellent long-term patency and outcomes. However, no studies have examined substances other than nitric oxide that could be beneficial for the bypass conduit, native coronary artery or ischemic myocardium. This study was conducted to evaluate differences in metabolic profiles between the LITA and ascending aorta using gas chromatography-time of flight-mass spectrometry (GC-TOF-MS).MethodsTwenty patients who underwent CABG using the LITA were prospectively enrolled. Plasma samples were collected simultaneously from the LITA and ascending aorta. GC-TOF-MS based untargeted metabolomic analyses were performed and a 2-step volcano plot analysis was used to identify distinguishable markers from two plasma metabolome profiles. Semi-quantitative and quantitative analyses were performed using GC-TOF-MS and enzyme-linked immunosorbent assay, respectively, after selecting target metabolites based on the metabolite set enrichment analysis.ResultsInitial volcano plot analysis demonstrated 5 possible markers among 851 peaks detected. The final analysis demonstrated that the L-cysteine peak was significantly higher in the LITA than in the ascending aorta (fold change = 1.86). The concentrations of intermediate metabolites such as L-cysteine, L-methionine and L-cystine in the 'cysteine and methionine metabolism pathway' were significantly higher in the LITA than in the ascending aorta (2.0-, 1.4- and 1.2-fold, respectively). Quantitative analysis showed that the concentration of hydrogen sulfide (H₂S) was significantly higher in the LITA.ConclusionThe plasma metabolome profiles of the LITA and ascending aorta were different, particularly higher plasma concentrations of L-cysteine and H₂S in the LITA

Acceptance of VR Shopping: Examining the Role of Technological Characteristics and Consumer Fashion Involvement

The present study examined the effect of vividness and interactivity, the two technological characteristics of VR, and fashion involvement, a consumer characteristic, on consumer’s intent to use VR stores under the framework of the Technology Acceptance Model (TAM). The subjects of the present study were asked to experience a commercially available fashion-brand VR store through a computer monitor and their responses were measured. The results revealed the effects of the technological characteristics of the VR store on consumer beliefs. The higher the perceived vividness of the VR store, the greater the perception that it is easy to use and playful. A higher level of perceived interactivity meant a higher degree of perceived usefulness, ease of use, and playfulness. The results also showed that consumer fashion involvement had a significant impact on perceived playfulness but not on perceived usefulness and ease of use. In addition, a higher degree of perceived ease of use translated into a higher level of perceived usefulness. Regarding the effect of consumer beliefs on usage intention, the more the VR store was perceived as being useful and the greater the playfulness derived from the experience, the higher the consumer intention to adopt the shopping platform. However, the perceived ease of use had a significantly negative impact on consumer usage intention. This shows that, even if VR stores are perceived as easy to use, a lack of perceived benefits, such as usefulness or playfulness, will negate their positive impact on consumer usage intention