Guocheng Lv, Dawei Jia, Changyou Li, Chunyu Zhao, Xiulu Zhang, Feng Yan, Hongzhuang Zhang and Bing Li
This study aims to investigate the effect of countersunk rivet head dimensions on the fatigue performance of the riveted specimens of 2024-T3 alloy.
Abstract
Purpose
This study aims to investigate the effect of countersunk rivet head dimensions on the fatigue performance of the riveted specimens of 2024-T3 alloy.
Design/methodology/approach
The relationship between rivet head dimensions and fatigue behavior was investigated by finite element method and fatigue test. The fatigue fracture of the specimens was analyzed by scanning electron microscopy.
Findings
A change of the rivet head dimensions will cause a change in the stress concentration and residual normal stress, the stress concentration near the rivet hole causes the fatigue crack source to be located on the straight section of the countersunk rivet hole and the residual normal stress can effectively restrain the initiation and expansion of fatigue cracks. The fatigue cycle will cause the rivet holes to produce different degrees of surface wear.
Originality/value
The fatigue life of the specimens with the height of the rivet head of 2.28 mm and 2.00 mm are similar, but the specimens with the height of the rivet head of 1.72 mm were far higher than the other specimens.
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Keywords
Wang Li, Xiuhua Gao, Xincheng Chen, Hongyan Wang, Changyou Zhu, Tong Li, Jun Wang, Hongyan Wu, Linxiu Du and Cairu Gao
This study aims to investigate the effect of different microstructures and its grain boundary character distribution (GBCD) on the corrosion behavior of weathering bridge steel.
Abstract
Purpose
This study aims to investigate the effect of different microstructures and its grain boundary character distribution (GBCD) on the corrosion behavior of weathering bridge steel.
Design/methodology/approach
The rust layer characteristics and corrosion resistance of specimens with different microstructures in the simulated industrial environment were studied by Electron Probe X-ray Micro-Analyzer, wavelength-dispersive spectrometer and electrochemical techniques. Electron backscatter diffraction technique was used to characterize the GBCD in steels with different microstructures.
Findings
Results revealed a significant difference in the corrosion susceptibility among the four microstructures, with corrosion rates decreasing in the following order: ferrite + pearlite > ferrite + bainite > bainite > martensite. The variation in corrosion resistance is primarily influenced by the microstructure type and the proportion of special grain boundaries, rather than the alloying elements. The proportion of Σ3 boundaries within the coincidence site lattice boundaries is positively correlated with improved corrosion resistance. A higher Σ3 boundary fraction resulted in a lower effective grain boundary energy, elevated self-corrosion potential, increased polarization resistance and reduced areas of localized galvanic corrosion; this led to enhanced inhibition of the electrochemical corrosion reaction, consequently reducing the corrosion rate.
Originality/value
This study elucidates and quantifies the intrinsic relationship between microstructure, GBCD and corrosion rate. This understanding is crucial for enhancing the corrosion resistance of weathering bridge steels in industrial atmospheric corrosion environments.
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Bin Mei, Micah Ezekiel, Changyou Sun and Yanshu Li
Using a 62,742-ha working forest in New Brunswick, Canada, we examine the benefit and cost of carbon additionality at the landscape level.
Abstract
Purpose
Using a 62,742-ha working forest in New Brunswick, Canada, we examine the benefit and cost of carbon additionality at the landscape level.
Design/methodology/approach
The baseline scenario is set to maximize timber profit over a 100-year planning period, whereas the carbon scenario is set to have a 5- or 10-year rotation extension.
Findings
At a carbon price of $8/tCO2e, the benefit of additional carbon sequestration from the working forest cannot offset its cost. For the benefit-cost ratio to be one, the respective break-even price needs to be $21/tCO2e for the 5-year rotation extension and $25/tCO2e for the 10-year rotation extension.
Originality/value
This study analyzes the carbon additionality and economics of working forests at the 50–100 thousand hectare scale. Specifically, we examine the change in benefit and cost between a baseline scenario of timber management only and a scenario of rotation extension for both timber and carbon sequestration.
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Shifu Chen, Hong Lei, Meng Wang, Changyou Ding, Weixue Dou and Lishan Chang
The reported mathematical models of gas–liquid flow in single snorkel Rheinstahl–Heraeus (SSRH) are based on the assumption of steady Ar-molten steel flow. The purpose of this…
Abstract
Purpose
The reported mathematical models of gas–liquid flow in single snorkel Rheinstahl–Heraeus (SSRH) are based on the assumption of steady Ar-molten steel flow. The purpose of this paper is to develop a mathematical model to describe the unsteady turbulent flow (CO-Ar-molten steel) with nonequilibrium decarburization reaction.
Design/methodology/approach
On the base of the finite volume method, the computational fluid dynamics software CFX is used to predict the unsteady fluid flow, the spatial distributions of CO/argon gas and carbon element. The water model experiment and the industrial experiment are carried out to verify the mathematical models.
Findings
A two-way coupling model (T-WCM) based on algebraic slip model is developed to investigate the coupling phenomena. The related results show that T-WCM is more rigorous and accurate than one-way coupling model in predicting carbon content of molten steel. The amount of CO gas, which can enhance turbulent flow and mass transfer, is about three times the argon gas blown into SSRH.
Originality/value
CO gas is the key factor in investigating the transport phenomena. This study fully reveals the truth about the unsteady gas-liquid flow in SSRH. It is necessary to adopt T-WCM based on algebraic slip model to describe the CO-Ar-molten steel flow phenomenon.
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Jasvinder Singh, Pulak Mohan Pandey, Tejinder Kaur and Neetu Singh
The purpose of this paper is to fabricate pre-existing geometries of the stents using solvent cast 3D printing (SC3P) and encapsulation of each stent with heparin drug by using…
Abstract
Purpose
The purpose of this paper is to fabricate pre-existing geometries of the stents using solvent cast 3D printing (SC3P) and encapsulation of each stent with heparin drug by using aminolysis reaction.
Design/methodology/approach
The iron pentacarbonyl powder and poly-ɛ-caprolactone blend (PCIP) were used to print stent designs of Art18z, Palmaz-Schatz and Abbott Bvs1.1. The properties of antithrombosis, anticoagulation and blood compatibility were introduced in the stents by conjugation of heparin drug via the aminolysis process. The aminolysis process was confirmed by energy dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy due to presence of amide group and nitrogen peak in the respective analysis. Biological studies were performed to depict the cell viability, hemocompatibility and antithrombotic properties. Besides, mechanical behaviors were analyzed to study the behavior of the stents under radial compression load and bending load.
Findings
The amount of heparin immobilized on the Art18z, Palmaz-Schatz and Abbott Bvs1.1 stents were 255 ± 27, 222 ± 30 and 212 ± 13 µg, respectively. The cell viability studies using L929 fibroblast cells confirmed the cytocompatibility of the stents. The heparinized SC3P printed stents displayed excellent thrombo-resistance, anticoagulation properties and hemocompatibility as confirmed by blood coagulation analysis, platelet adhesion test and hemolysis analysis. Besides, mechanical behavior was found in context of the real-life stents. All these assessments confirmed that the developed stents have the potential to be used in the real environment of coronary arteries.
Originality/value
Various customized shaped biodegradable stents were fabricated using 3D printing technique and encapsulated with heparin drug using aminolysis process.