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
Dongjun Lv, Xiaolei Zhang, Guocheng Gao, Jing Tang, Zilong Zhang, Yihui Liu, Ran Wang and LeiFang Liu
The purpose of this study was the preparation of a poly(styrene-co-maleic anhydride)-g-polyetheramine (SMA-g-PEA) hyperdispersant that reduces the viscosity of the system and…
Abstract
Purpose
The purpose of this study was the preparation of a poly(styrene-co-maleic anhydride)-g-polyetheramine (SMA-g-PEA) hyperdispersant that reduces the viscosity of the system and improves the colouring intensities of pigments.
Design/methodology/approach
PEA of specific quality was dissolved in propylene glycol methyl ether. SMA was then added according to the required mass ratio. The solution was refluxed for 10 h under a stream of protective N2. The prepared hyperdispersant was then characterised by Fourier-transform infrared, UV–visible and 1H NMR spectroscopies, gel-permeation chromatography and thermogravimetry.
Findings
PEA was successfully grafted onto the SMA polymer and the synthesised product was found to be thermally stable. The copolymer with a 6:1 mass ratio is the best dispersant and was used to disperse carbon black, phthalocyanine blue and permanent violet in water-based systems, which helps to improve the application performance of each pigment by reducing the viscosity of the system and improving the colouring intensity of the pigment. The water dispersion is stable and does not exhibit an increase in viscosity after seven days of oven aging at 50°C.
Originality/value
SMA-g-PEA water-based hyperdispersants were successfully synthesised. The prepared hyperdispersants help to improve the application performance of each studied pigment by reducing the viscosity of the system and improving the colouring intensity of the pigment.
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Mingzhi Hu, Lina Wu, Guocheng Xiang and Shihu Zhong
Using data from the China Health and Nutrition Survey, this work examines the relationship between housing price and the probability of marriage among the young.
Abstract
Purpose
Using data from the China Health and Nutrition Survey, this work examines the relationship between housing price and the probability of marriage among the young.
Design/methodology/approach
By exploiting land reform as an exogenous change in housing price and employing a differences-in-differences framework, this study investigates the effects of housing price on the marriage probability of young people.
Findings
This work confirms that land reform decreased young people's likelihood of marriage. This finding is robust to a series of model specifications. The effects of land reform increased over time because of rising housing unaffordability from progressively inflating housing prices. Moreover, land reform had larger effects on renters and young adults aged below 30 than homeowners and young adults aged above 30.
Social implications
Overall, this study highlights the negative consequences of an overheated housing market on marriage in developing countries.
Originality/value
Housing prices have increased dramatically in urban China after 2002 upon the implementation of the assignment system of the use right of all kinds of profit-oriented lands by means of public bidding, auction and quotation. High housing prices indicate serious housing unaffordability, especially for young people who typically have low income and wealth. Homeownership that comes with various benefits can theoretically increase the likelihood of marriage, particularly in China where a house is often regarded as a prerequisite for marriage.
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Keywords
Qiuping Yang, Huizhi Li, Yubo Zhai, Xiaofeng Li and Peizhi Zhang
To prepare a new type of composite for selective laser sintering 3D printing, the surface of Al2O3 nanoparticles was modified by the coupling agent…
Abstract
Purpose
To prepare a new type of composite for selective laser sintering 3D printing, the surface of Al2O3 nanoparticles was modified by the coupling agent (3-methacryloxypropyl)-trimethoxy silane (KH570) before coated with thermoplastic epoxy resin (TER).
Design/methodology/approach
Laser diffraction confirmed that the size distribution of prepared powder materials in this study ranged between 20 to 80 µm. Thermogravimetric analysis (TGA) showed that the loading of organic matter was below 5 per cent. Fourier transform infrared spectroscopy indicated that the silane coupling agent molecule bound strongly with the alumina. X-ray diffraction confirmed the prepared powder materials to be α-alumina. Through the angle of repose (AOR) test, the AOR = 18.435º was obtained, suggesting the high flowability of prepared powder materials. Scanning electron microscopy (SEM) observation demonstrated that the shape of the prepared powder materials was sphere-like grains.
Findings
Molding properties of prepared powder materials were studied on the basis of particle size distribution, particle size, sphericity, crystal structure and the reaction mode of the TER. This prepared powder materials can be well applied to the production of epoxy resin-coated Al2O3 composite parts with high precision and good mechanical performance.
Originality/value
This composite can be well applied to the production of epoxy resin-coated Al2O3 composite parts with high precision and good mechanical performance.