The Shear Behavior of Double-superposed Panels Reinforced with Different Shear Connectors

Wenying Zhang,Lianping Yang,Shaole Yu,Junsheng Yan 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.10

The shear behavior of a new type of sandwich structure, double-superposed panels, is investigated by conducting push-out test and finite element analysis in this paper. Experiments have been carried out to characterize the effect on the shear behavior of two different shear connector configurations: truss connector and tic-tac-toe connector. Based on finite element analysis, a parameter study is conducted, with the major parameters considered being the diameter, height and pitch of shear connector. Test results indicate that the delamination between the precast layers and core layer is the main failure mode for all specimens, and the crack formation and crack development between the two interfaces is not in synch. It’s also revealed that the specimens with tic-tac-toe connections present higher ultimate shear strength, as well as better ductility during the process of failure, compared to those with truss connections. The results of the numerical simulations show that the ultimate shear strength and the ductility of both connector configurations increases as the diameter of the shear connector increases; increasement in height of shear connector has a negligible effect on the shear behavior; when the pitch length is increased, the ultimate shear strength of the truss connector specimen increases, which is the inverse behavior of the specimen with tic-tac-toe connector.

Utilization of Completely Recycled Fine Aggregate for Preparation of Lightweight Concrete Partition Panels

Yibo Yang,Baixi Chen,Weizhen Zeng,Yanjun Li,Qiaohui Chen,Wenying Guo,Hengchang Wang,Yingqin Chen 한국콘크리트학회 2021 International Journal of Concrete Structures and M Vol.15 No.5

To reduce the cost of lightweight concrete (LWC) partition panels and to address recycling concrete waste, this work utilized completely recycled fine aggregate (CRFA) to replace the natural fine aggregate and ceramsite in the preparation of LWC and LWC partition panels. To this end, an autoclave-free curing process and an air-entraining agent were used to prepare the CRFA-LWC. The workability, compressive strength, drying shrinkage, and pore structure of the CRFA-LWC and the performance of the CRFA-LWC partition panels were then investigated. The results show that the optimal ratio of the CRFA to the cement is 2.2 for the lightweight concrete, and the optimal panel cross section is a rounded rectangular one. All the pores in the CRFA-LWC have a diameter of smaller than 0.17 mm, and the diameter of 89% of them is less than 0.05 mm. In order to satisfy the drying shrinkage requirements stipulated by Chinese code JC/T 169-2016, the CRFA-LWC should be cured for at least 10 days. The economic analysis concludes that the material cost of CRFA-LWC is 40% lower than that of the autoclaved ceramsite concrete. In addition, utilizing CRFA in lightweight concrete can ease the shortage of natural aggregate.

Performances of Concrete Columns with Modular UHPC Permanent Formworks Under Axial Load

Yibo Yang,Baixi Chen,Yong Chen,Huanyang Zhou,Fucai Liu,Xiangming Xie,Junsheng Chen,Wenying Guo,Hengchang Wang 한국콘크리트학회 2023 International Journal of Concrete Structures and M Vol.17 No.5

This research proposed the modular prefabricated permanent formwork system made of ultra-high-performance concrete (UHPC). Two kinds of modular formwork shapes were designed: the flat formwork and the ribbed. The experimental investigation on the axial compression performance of the composite columns that consist of the normal strength concrete (NSC) core and the modular UHPC permanent formwork was demonstrated. Compared with the flat formwork, the ribbed formwork exhibited better bonding with the NSC core. As observed from the test results, the composite column with the ribbed formwork presented a similar axial behavior as the NSC column with a slight improvement in ultimate loads. Therefore, the modular UHPC ribbed permanent formwork could be regarded as the additional cover to the conventional NSC column. In addition, the finite element analysis (FEA) model was also developed to simulate the composite columns numerically. The predicted capacities agreed with the experimental results, which validated the numerical models. The crack pattern estimated by the FEA model revealed that the interaction between the permanent formwork and the inner concrete introduced many tiny cracks to the concrete core. However, as protected by the UHPC permanent formwork, the overall durability of the composite columns can still be enhanced.

Development and Evaluation of a Duplex Real-Time PCR Assay With a Novel Internal Standard for Precise Quantification of Plasma DNA

Dan Chen,Shi-yang Pan,Erfu Xie,Li Gao,Huaguo Xu,Wenying Xia,Ting Xu,Peijun Huang 대한진단검사의학회 2017 Annals of Laboratory Medicine Vol.37 No.1

Background: Circulating levels of cell-free DNA increase in many pathologic conditions. However, notable discrepancies in the quantitative analysis of cell-free DNA from a large number of laboratories have become a considerable pitfall, hampering its clinical application. Methods: We designed a novel recombinant DNA fragment that could be applied as an internal standard in a newly developed and validated duplex real-time PCR assay for the quantitative analysis of total cell-free plasma DNA, which was tested in 5,442 healthy adults and 200 trauma patients. Results: Compared with two traditional methods, this novel assay showed a lower detection limit of 0.1 ng/mL, lower intra- and inter-assay CVs, and higher accuracy in the recovery test. The median plasma DNA concentration of healthy males (20.3 ng/mL, n=3,092) was significantly higher than that of healthy females (16.1 ng/mL, n=2,350) (Mann-Whitney two-sample rank sum test, P<0.0001). The reference intervals of plasma DNA concentration were 0-45.8 ng/mL and 0-52.5 ng/mL for healthy females and males, respectively. The plasma DNA concentrations of the majority of trauma patients (96%) were higher than the upper normal cutoff values and were closely related to the corresponding injury severity scores (R2=0.916, P<0.0001). Conclusions: This duplex real-time PCR assay with a new internal standard could eliminate variation and allow for more sensitive, repeatable, accurate, and stable quantitative measurements of plasma DNA, showing promising application in clinical diagnosis.

A Type of Subsection Model for a Permanent Magnet Bar and its Leakage Permeance Calculation Method in an Open Magnetic Circuit

Huimin Liang,Jiaxin You,Wenying Yang,Guofu Zhai 한국자기학회 2014 Journal of Magnetics Vol.19 No.1

The equivalent model of a permanent magnet (PM) plays an important role in electromagnetic system calculation. A type of subsection model for a PM bar is established, to improve the accuracy of the traditional equivalent circuit method. The mathematical expression, and its end verification condition, are presented. Based on the analytical method and finite element method, the leakage permeance calculation of a PM bar in an open magnetic circuit is investigated. As an example, for a given certain type of PM bar, the magnetic flux of each section is validated by experiment, and by simulation. This model offers a foundation for building a high accuracy equivalent magnetic PM model in an electromagnetic system.

Nanosponge membrane with 3D-macrocycle b-cyclodextrin as molecular cage to simultaneously enhance antifouling properties and efficient separation of dye/oil mixtures

Sisi Ma,Ligang Lin,Xinyang Li,Wenying Shi,Xiaofei Zhai,Jing Yang 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.112 No.-

Developing multifunctional, efficient and durable membrane for treating complex oily wastewater ishighly desirable but still a challenge due to the severe membrane fouling. Herein, nanosponge membranewith 3D-macrocycle b-cyclodextrin (b-CDs) as molecular cage was manufactured by azide-alkyne clickreaction for oil/water treatment and antifouling properties simultaneously. The macrocyclic ‘molecularcage’ geometry of b-CDs can induce various guest molecules into their cavities. When clickable b-CDN3was fixed onto a clickable EVAL- membrane surface, the hydrophilicity of the membrane was greatlyimproved. Furthermore, the molecular cage–grafted membrane (EVAL-g-CD) showed better antifoulingperformance than a pure EVAL membrane, with lower water flux decline (15%) and higher water fluxrecovery (91%). The flux and separation efficiency values of the EVAL-g-CD membrane were higher than120 Lm2h1 and 99%, respectively. The EVAL-g-CD membrane also exhibited good adsorption performancefor organic pollutants owing to its cavity structure. Furthermore, the membrane showed desirablestability and its rejection remained at 99% after filtration. This proposed 3D membrane strategy based onmolecular cages sheds light on the formation of hydrophilic membrane surfaces and shows great promisefor potential applications such as the separation of oil-in-water emulsions.