Seismic performance analysis of steel beam to CFST column connection with ductility and energy dissipation components

Concrete-filled steel tubular (CFST) column to steel beam joint with the ductility and energy dissipation components is a type of connection which is used in prefabricated structures, to improve the capacity of connections and construction efficiency. In this paper, two different type of steel beam to CFST column connections with the penetrated high-strength bolts and end-plate are investigated, i.e., steel beam to CFST column connection with end plate (CJ-1), and T-stub bolted (CJ-2) connections. The finite element model (FEM) of steel beam to CFST column connection with the penetrated high-strength bolts under cyclic loading are conducted based on the whole process of the nonlinear explicit analysis method using ABAQUS. The feasibility of FEM is verified by a set of experimental results performed by our research group, as well as available test results from other researchers. The failure modes, bearing capacity, energy dissipation capacity and ductility and rigidity degeneration were studied. As a result, the load-displacement hysteretic loop curve of CJ-2 connection is plump. However, the hysteresis curve of CJ-1 shows pinching phenomenon. The value of buckling load and ultimate load of CJ-2 increased by 28 % and 30 % respectively, compared with CJ-1. With respect of stress analysis, the plastic strain accumulation position distribution is relatively uniform duo to the T-stub connection, avoiding the penetrated high-strength bolt early yield or fracture. The results show that the steel beam to CFST column connection with penetrated bolts and T-stub connection has good seismic capacity

Antipredator Behavior Produced by Heterosexual and Homosexual Tandem Running in the Termite Reticulitermes chinensis (Isoptera: Rhinotermitidae)

Heterosexual and homosexual tandem running can be observed together in the alate pairings in some species of termites. This study examined the effect of heterosexual and homosexual tandem running in the termite Reticulitermes chinensis on the predation risk by a predatory ant, Leptogenys kitteli. Results showed that both heterosexual and homosexual tandem running reduced the predation risk of participants. When a male-male tandem encountered a female, the back male had a significant advantage over the front male in winning a female. Moreover, the back males were significantly heavier than the front males. These results indicated that the predation risk of dealates could be decreased by tandem running through the dilution effect. Furthermore, these data suggest that male-male tandem running could induce selection pressure in favor of vigorous males and may play an essential role in indirect sexual selection

Seismic performance analysis of steel beam to CFST column connection with ductility and energy dissipation components

Concrete-filled steel tubular (CFST) column to steel beam joint with the ductility and energy dissipation components is a type of connection which is used in prefabricated structures, to improve the capacity of connections and construction efficiency. In this paper, two different type of steel beam to CFST column connections with the penetrated high-strength bolts and end-plate are investigated, i.e., steel beam to CFST column connection with end plate (CJ-1), and T-stub bolted (CJ-2) connections. The finite element model (FEM) of steel beam to CFST column connection with the penetrated high-strength bolts under cyclic loading are conducted based on the whole process of the nonlinear explicit analysis method using ABAQUS. The feasibility of FEM is verified by a set of experimental results performed by our research group, as well as available test results from other researchers. The failure modes, bearing capacity, energy dissipation capacity and ductility and rigidity degeneration were studied. As a result, the load-displacement hysteretic loop curve of CJ-2 connection is plump. However, the hysteresis curve of CJ-1 shows pinching phenomenon. The value of buckling load and ultimate load of CJ-2 increased by 28 % and 30 % respectively, compared with CJ-1. With respect of stress analysis, the plastic strain accumulation position distribution is relatively uniform duo to the T-stub connection, avoiding the penetrated high-strength bolt early yield or fracture. The results show that the steel beam to CFST column connection with penetrated bolts and T-stub connection has good seismic capacity

Optimization of extraction conditions and determination of purine content in marine fish during boiling

Background Gout is the second most common metabolic disease affecting human health. The disease of gout is closely related to the level of uric acid, which is the end-product of human purine metabolism. Moreover, food is the main way of external ingestion of purine. Method A simple and time-saving method was developed to extract purines like adenine, hypoxanthine, guanine, and xanthine from marine fish by single factor design combined with Box–Behnken. The contents of these purines in the edible parts and internal organs of marine fish, as well as Scophthalmus maximus, were determined by high-performance liquid chromatography to investigate the relationship between the boiling process and purine content. Result The mixed-acid method was chosen for the extraction of purine bases and the extraction conditions were as follows: mixture acid 90.00% TFA/80.00% FA (v/v, 1:1); hydrolysis temperature 90.00 °C; time 10.00 min; liquid-to-solid ratio 30:1. The total purine content of the edible parts (eyes, dorsal muscles, abdominal muscles, and skin) was the highest in Scophthalmus maximus, followed by sphyraena, Sardinella, Trichiurus lepturus, Scomberomorus niphonius, Pleuronectiformes, Sea catfish, Anguillidae, and Rajiformes. Moreover, boiling significantly reduced the purine content in the marine fish because of the transfer of the purines to the cooking liquid during boiling. Scophthalmus maximus, Sphyraena, and Sardinella were regard as high-purine marine fish, which we should eat less. We also confirmed that boiling significantly transferred purine bases from fish to cooking liquid. Thus, boiling could reduce the purine content of fish, thereby reducing the risk of hyperuricemia and gout

Adsorption Behaviors of 17 -Ethinylestradiol in Sediment-Water System in Northern Taihu Lake, China

Adsorption behavior of 17 -ethinylestradiol (EE2) in northern Taihu Lake sediment was analyzed by using batch equilibrium experiment. Freundlich isotherm could describe the adsorption thermodynamic behavior of EE2 in sediment. Sediment organic matter (SOM) contents had important impacts on the adsorption capacity for EE2. The pH values also influenced the adsorption capacity for EE2. Increase of pH value could decrease the EE2 adsorption, which might be due to the electrostatic repulsion between the anionic form of EE2 and sediments with negative charge under high pH values. Competitive effects of bisphenol A (BPA) on EE2 adsorption were further analyzed. The results showed that low concentration BPA did not have significant influences on EE2 adsorption. However, high concentration BPA could reduce EE2 adsorption, which might be due to the similar molecular diameter of BPA with adsorption sites and one more benzene ring with a hydroxyl group in BPA. These results provide primary information of EE2 adsorption in sediment-water system in Taihu Lake, which is useful for the environmental risk assessment and management of EE2 in studied area

Enterprise risk management and firm value within China's insurance industry

Orientation: The article discusses the relationship between enterprise risk management (ERM) and firm value.Research purpose: The purpose of the study is to empirically examine the relationship between ERM and firm value. The study is undertaken within the context of the Chinese insurance industry.Motivation for the study: Recent attempts to link ERM with firm value have been undertaken primarily in the USA and Europe and have produced ambiguous and inconclusive findings.Research design, approach and method: Data was obtained from the China Insurance Regulatory Commission, a government body responsible for regulating insurance products and services in China. The data sample consisted of 135 insurance companies operating in China (in 2010). Regression modelling is employed to analyse the data.Main findings: The results show the relationship between ERM and firm value at first appears statistically significant within a Pearson correlation matrix but then falls below statistical significance on closer scrutiny through regression analysis. Accordingly, it is recommended that insurers in China should not look to aggressive investment in ERM as a strategy for producing quick gains in firm value.Practical/managerial implications: Risk managers should plan ERM development from a risk management maturity perspective, which equates the highest level of ERM development with ERM’s capacity to improve firm resilience to the unknown and serve as a mechanism for strategic decision-making.Contribution/value-add: The study employed return on equity as a proxy for firm value, utilising ordinary least squares regression modelling to test propositions of the relationships between variables