Modeling of RC shear walls using shear spring and fiber elements for seismic performance assessment

Reinforced concrete shear wall is one of the most effective members during severe lateral loads especially in earthquakes and winds. Extensive researches, both analytical and experimental, have been carried out to study the behavior of reinforced concrete (RC) shear walls. Predicting inelastic response of RC walls and wall systems requires accurate, effective, and robust analytical model that incorporate important material characteristics and behavioral response features. In this study, a modeling method using fiber and spring elements is developed to capture inelastic responses of an RC shear wall. The fiber elements and the spring reflect flexural and shear behaviors of the shear wall, respectively. The fiber elements are built by inputting section data and material properties. The parameters of the shear spring that represent strength and stiffness degradation, pinching, and slip are determined based on analysis results from a detailed finite element method (FEM) model. The reliability of the FEM analysis program is verified. The applicability of the proposed modeling method is investigated by performing inelastic dynamic analyses for reference buildings with various aspect ratios of shear walls

Modeling of RC shear walls using shear spring and fiber elements for seismic performance assessment

Reinforced concrete shear wall is one of the most effective members during severe lateral loads especially in earthquakes and winds. Extensive researches, both analytical and experimental, have been carried out to study the behavior of reinforced concrete (RC) shear walls. Predicting inelastic response of RC walls and wall systems requires accurate, effective, and robust analytical model that incorporate important material characteristics and behavioral response features. In this study, a modeling method using fiber and spring elements is developed to capture inelastic responses of an RC shear wall. The fiber elements and the spring reflect flexural and shear behaviors of the shear wall, respectively. The fiber elements are built by inputting section data and material properties. The parameters of the shear spring that represent strength and stiffness degradation, pinching, and slip are determined based on analysis results from a detailed finite element method (FEM) model. The reliability of the FEM analysis program is verified. The applicability of the proposed modeling method is investigated by performing inelastic dynamic analyses for reference buildings with various aspect ratios of shear walls

FEASIBILITY OF BREWING MAKGEOLLI (TURBID RICE WINE) USING PARTIALLY GELATINIZED WHEAT FLOUR AND TAPIOCA FLOUR

Makgeolli is made from cooked rice or wheat, then brewed with nuruk (Korean fermentation starter) for several days. But, nowadays, attempts have been made to use various raw materials and process innovations to make makgeolli for particular purposes.  This study aimed to evaluate the quality of makgeolly made from partially gelatinized wheat flour and tapioca flour. Five different combination of wheat flour and tapioca flour were used to manufacture makgeolli. The results showed that different combination of partially gelatinized wheat flour and tapioca flour significantly affected the chemical and sensorial characteristics of makgeolli. Increasing proportion of wheat flour produced higher level of total acid, amino acidity, reducing sugar and total solid of makgeolli. Inversely, alcohol content was higher when higher level of tapioca flour was used. In general, sensorial characteristics of makgeolli made from partially gelatinized wheat flour and tapioca flour didn’t acceptable by panelists. Thus, brewing makgeolli by using partially gelatinized wheat flour and tapioca flour isn’t acceptable in term of sensorial characteristics

Evaluation of a Sodium–Water Reaction Event Caused by Steam Generator Tubes Break in the Prototype Generation IV Sodium-cooled Fast Reactor

AbstractThe prototype generation IV sodium-cooled fast reactor (PGSFR) has been developed by the Korea Atomic Energy Research Institute. This reactor uses sodium as a reactor coolant to transfer the core heat energy to the turbine. Sodium has chemical characteristics that allow it to violently react with materials such as a water or steam. When a sodium–water reaction (SWR) occurs due to leakage or breakage of steam generator tubes, high-pressure waves and corrosive reaction products are produced, which threaten the structural integrity of the components of the intermediate heat-transfer system (IHTS) and the safety of the primary heat-transfer system (PHTS). In the PGSFR, SWR events are included in the design-basis event. This event should be analyzed from the viewpoint of the integrities of the IHTS and fuel rods. To evaluate the integrity of the IHTS based on the consequences of the SWR, the behaviors of the generated high-pressure waves are analyzed at the major positions of a failed IHTS loop using a sodium–water advanced analysis method-II code. The integrity of the fuel rods must be consistently maintained below the safety acceptance criteria to avoid the consequences of the SWR. The integrity of the PHTS is evaluated using the multidimensional analysis of reactor safety-liquid metal reactor code to model the whole plant

The Association between Apolipoprotein A-II and Metabolic Syndrome in Korean Adults: A Comparison Study of Apolipoprotein A-I and Apolipoprotein B

BackgroundApolipoprotein A-II (apoA-II) is the second-most abundant apolipoprotein in human high-density lipoprotein and its role in cardio metabolic risk is not entirely clear. It has been suggested to have poor anti-atherogenic or even pro-atherogenic properties, but there are few studies on the possible role of apoA-II in Asian populations. The aim of this study is to evaluate the role of apoA-II in metabolic syndrome (MetS) compared with apolipoprotein A-I (apoA-I) and apolipoprotein B (apoB) in Korean adults.MethodsWe analyzed data from 244 adults who visited the Center for Health Promotion in Pusan National University Yangsan Hospital for routine health examinations.ResultsThe mean apoB level was significantly higher, and the mean apoA-I level was significantly lower, in MetS; however, there was no significant difference in apoA-II levels (30.5±4.6 mg/dL vs. 31.2±4.6 mg/dL, P=0.261). ApoA-II levels were more positively correlated with apoA-I levels than apoB levels. ApoA-II levels were less negatively correlated with homocysteine and high sensitivity C-reactive protein levels than apoA-I levels. The differences in MetS prevalence from the lowest to highest quartile of apoA-II were not significant (9.0%, 5.7%, 4.9%, and 6.6%, P=0.279). The relative risk of the highest quartile of apoA-II compared with the lowest quartile also was not significantly different (odds ratio, 0.96; 95% confidence interval, 0.95 to 1.04; P=0.956).ConclusionCompared with apoA-I (negative association with MetS) and apoB (positive association with MetS) levels, apoA-II levels did not show any association with MetS in this study involving Korean adults. However, apoA-II may have both anti-atherogenic and pro-atherogenic properties

Activation of spleen tyrosine kinase is required for TNF-α-induced endothelin-1 upregulation in human aortic endothelial cells

AbstractEndothelin-1 (ET-1) promotes atherosclerosis. We tested whether spleen tyrosine kinase (Syk) mediates tumor necrosis factor-α (TNF-α)-induced ET-1 upregulation in human aortic endothelial cells (HAECs) and sought to identify the signal pathways involved. TNF-α-induced reactive oxygen species (ROS) activated Syk and phosphatidylinositol 3-kinase (PI3K), which was required for the activation of AP-1 and subsequent ET-1 gene transcription. ROS mediated c-Jun NH2-terminal kinase (JNK) is also required for AP-1 activation, but Syk and PI3K regulated AP-1 activation independently of JNK. Through regulation of ET-1 production, Syk could be implicated in atherosclerosis