Experimental study on bearing capacity of PFCC column-RC beam joint reinforced with CST

Ping Wu,Dongang Li,Feng Yu,Yuan Fang,Guosheng Xiang,Zilong Li 국제구조공학회 2023 Steel and Composite Structures, An International J Vol.47 No.1

An experimental study of eleven PVC-FRP Confined Concrete (PFCC) column-Reinforced Concrete (RC) beam joints reinforced with Core Steel Tube (CST) under axial compression is carried out. All specimens are designed in accordance with the principle of “weak column and strong joint”. The influences of FRP strips spacing, length and steel ratio of CST, height and stirrup ratio of joint on mechanical behavior are investigated. As the design anticipated, all specimens are destroyed by column failure. The failure mode of PFCC column-RC beam joint reinforced with CST is the yielding of longitudinal steel bars, CST and stirrups of column as well as the fracture of FRP strips and PVC tube. The ultimate bearing capacity decreases as FRP strips spacing or joint height increases. The effects of other three studied parameters on ultimate bearing capacity are not obvious. The strain development rules of longitudinal steel bars, PVC tube, FRP strips, column stirrups and CST are revealed. The effects of various studied parameters on stiffness are also examined. Additionally, an influence coefficient of joint height is introduced based on the regression analysis of test data, a theoretical formula for predicting bearing capacity is proposed and it agrees well with test data.

Association between Plasma Osmolality and Case Fatality within 1 Year after Severe Acute Ischemic Stroke

Meng Liu,Yilun Deng,Yajun Cheng,Zilong Hao,Simiao Wu,Ming Liu 연세대학교의과대학 2021 Yonsei medical journal Vol.62 No.7

Purpose: Plasma osmolality, a marker of dehydration, is associated with cardiovascular mortality. We aimed to investigatewhether elevated plasma osmolality is associated with case fatality within 1 year after severe acute ischemic stroke. Materials and Methods: We included severe ischemic stroke patients (defined as National Institutes of Health Stroke Scale ≥15score) within 24 hours from symptom onset admitted to the Department of Neurology, West China Hospital between January 2017and June 2019. Admission plasma osmolality was calculated using the equation 1.86*(sodium+potassium)+1.15*glucose+urea+14. Elevated plasma osmolality was defined as plasma osmolality >296 mOsm/kg, indicating a state of dehydration. Study outcomesincluded 3-month and 1-year case fatalities. Multivariable logistic regression was performed to determine independent associationsbetween plasma osmolality and case fatalities at different time points. Results: A total of 265 patients with severe acute ischemic stroke were included. The mean age was 71.2±13.1 years, with 51.3%being males. Among the included patients, case fatalities were recorded for 31.7% (84/265) at 3 months and 39.6% (105/265) at1 year. Elevated plasma osmolality (dehydration) was associated with 3-month case fatality [odds ratio (OR) 1.98, 95% confidenceinterval (CI) 1.07–3.66, p=0.029], but not 1-year case fatality (OR 1.51, 95% CI 0.84–2.72, p=0.165), after full adjustment for confoundingfactors. Conclusion: Elevated plasma osmolality was independently associated with 3-month case fatality, but not 1-year case fatality, forsevere acute ischemic stroke.

Genetic and phylogenetic analysis of the honey bee sacbrood virus from jiangxi isolates

Meng Yaping,Yu Xinyue,Huang Qiang,Zhang Li Zhen,Wu Xiaobo,Wang Zilong,Yan Wei Yu 한국응용곤충학회 2022 Journal of Asia-Pacific Entomology Vol.25 No.1

The high prevalence of honeybee viral diseases poses a severe threat to the health of honeybees and causes substantial economic losses worldwide. Sacbrood virus (SBV) is a single-strand RNA virus that infects honeybees at all life stages. The infection can shorten the lifespan of adult bees and is lethal to larvae. SBV is the major cause of honeybee losses in Asia. Genetic and phylogenetic analyses of SBV isolates from different areas have been previously conducted. However, the impact of Apis mellifera Linnaeus and Apis cerana Fabricius coexistence on the infection and phylogeny of SBV remains unknown. In this study, we collected A. cerana and A. mellifera samples from commercial apiaries, only A. cerana in mountainous region. SBV prevalence was evaluated in three commercial apiaries of Jinxi, Tonggu and Nanchang and two mountainous regions of Zixi and Yifeng. In our sampling location, we found a higher SBV prevalence in the mountainous regions than in commercial apiaries. Partial structural polyprotein coding sequences were sequenced and compared with other GenBank SBV isolates. Phylogenetic tree topologies showed that SBV isolates form two major groups based on their host specificity, and isolates from same country tend to cluster together in subclades, indicating that the host and geographic region has significant effects on SBV strain specificity.

Application Research on Mechanical Strength and Durability of Porous Basalt Concrete

Zhu, Yuelei,Li, Jingchun,Zhu, He,Jin, Long,Ren, Qifang,Ding, Yi,Li, Jinpeng,Sun, Qiqi,Wu, Zilong,Ma, Rui,Oh, Won-Chun Materials Research Society of Korea 2022 한국재료학회지 Vol.32 No.3

Porous basalt aggregate is commonly used in roadbed engineering, but its application in concrete has rarely been studied. This paper studies the application of porous basalt in concrete. Porous basalt aggregate is assessed for its effects on mechanical strength and durability of prepared C50 concrete; because it has a hole structure, porous basalt aggregate is known for its porosity, and porous basalt aggregates can be made full of water through changing the content of saturated basalt; after full-water condition is achieved in porous basalt aggregate mixture of C50 concrete, we discuss its mechanical properties and durability. The effects of C50 concrete prepared with basalt aggregate on the compressive strength, water absorption, and electric flux of concrete specimens of different ages were studied through experiments, and the effects of different replacement rates of saturated porous basalt aggregate on the properties of concrete were also studied. The results show that porous basalt aggregate can be prepared as C50 concrete. For early saturated porous basalt aggregate concrete, its compressive strength decreases with the increase of the replacement rate of saturated aggregate; this occurs up to concrete curing at 28 d, when the replacement rate of saturated basalt aggregate is greater than or equal to 40 %. The compressive strength of concrete increases with the increase of the replacement rate of saturated aggregate. The 28 d electric flux decreases with the increase of the replacement rate of saturated aggregate, indicating that saturated porous basalt aggregate can improve the chloride ion permeability resistance of concrete in later stages.

Study on preparation of inorganic binder stabilized material with large dosage of phosphogypsum

Sun Qiqi,Tao Liangjing,Li Xin,Xu Wei,Yao Shuo,Li Jinpeng,Ren Qi-Fang,Chen Yue’e,Xu Chunshan,Wu Zilong,Zhu Yuelei,Ding Yi,오원춘 한국세라믹학회 2023 한국세라믹학회지 Vol.60 No.6

With the rapid development of the phosphorus chemical industry, a large amount of phosphogypsum (PG) is discharged. The impurities in PG pollute the surrounding soil, the groundwater and the air in the long-term storage. In this paper, PG as the main raw material is used to study the stable material of inorganic binder in the condition of large dosage of PG. With PG and graded gravel as stabilized materials, and cement and fly ash as binder, materials are mixed to determine the influence of PG ratio and the amount of activator on the mixture. The results show that the mechanical strength of the mixture increased first and then decreased with the increase in the proportion of PG replacing graded gravel in the mixture. The activator significantly improves the properties of the material system and makes a significant contribution to the curing of PG. The best ratio of pretreated PG: cement: fly ash: aggregate is 50:6:5:39. The amount of activator added by the external mixing method is 0.3%, which can make the unconfined compressive strength reach 4.1 MPa after 7d. Finally, water-soluble phosphorus leaching experiment is conducted for all the samples. The results show that phosphorus leaching is so little that no secondary pollution of the environment is caused.