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The major concern technologies during the processing through three-dimensional printing (3DP) are the mechanical and boundary properties of sand models. The parameters such as activator content, resolution X, layer thickness and re-coater speed play a vital role in 3DP sand components. The purpose of this paper is to recommend the optimal process parameters for the best sand mold properties.

In this paper, taking the parameters of the activator content, resolution X, layer thickness and re-coater speed as the influence factors, an orthogonal test of L16(44) was designed to discuss the influences of those parameters on the mechanical and boundary properties. Three-point bending (3PB) test was used to characterize the actual bending strength, and the boundary accuracy was assessed by the deviation of the three-point bending samples compared with its design scale.

The experimental results showed that the resolution X and layer thickness are the main parameters affecting sand mold properties. The strength will attain its maximum when the resolution X and layer thickness are the minimum. The optimal parameters were screened and verified by the confirmation test. The optimal process parameters for best strength and less gas evolution are the activator of 0.19%, resolution X of 0.1 mm, layer thickness of 0.28 mm and re-coater speed of 210 mm/s.

The novelty of this paper is the select of significant parameters on 3D-printed sand model properties. A mathematical model was built to analyze the effect of these parameters. The optimal process parameters for the best properties were got.

The purpose of this paper is to demonstrate by experiments that non‐linear Lamb wave modulation spectrum (NLWMS) will be a good indicator of fatigue cracks in a metallic plate.

A system composed of piezoelectric transducers, arbitrary waveform generator, power amplifier, laser vibrometer, digital oscilloscope and computer has been constructed, and using this system, three samples made of 7075‐T6 aluminium alloy plates are studied, respectively. One is with a fatigue crack, one is with a through hole and the other is intact.

The experimental results show that there are no significant harmonics and sidebands in the intact sample, and there are no modulation frequencies in the drilled‐hole sample. On the contrary, in the cracked sample, there is an abundance of the harmonics and sidebands. Therefore, these new modulation frequency components can be used to indicate the presence of the fatigue crack.

This paper will provide a method for detecting fatigue crack in metallic plates, especially aluminium alloy plates for aerospace applications.

Under the excitation of two different frequency Lamb waves, experiments on 7075‐T6 alloy plates show that new rising modulation frequency components can be used to indicate the presence of the crack. So, the fatigue crack in metallic plates can be detected by NLWMS.

This study investigates how different parental mediation strategies (active versus restrictive) and teen Douyin users' privacy risk perceptions are associated with their privacy management behaviors.

An online survey with teen Douyin users (N = 500) was administered in mainland China.

Perceived privacy risk leads teenagers to implement stricter privacy management strategies. However, different types of parental mediation have different impacts on teens' privacy management behaviors. Discussion-based active mediation is positively correlated with privacy disclosure and privacy boundary linkage, while rule-based restrictive mediation is positively associated with privacy boundary control. In addition, active mediation encourages teens to use their own judgment about privacy risks when deciding how much personal information to disclose and with whom they want to share their information. Conversely, restrictive mediation results in teens making decisions about disclosing private information without taking their own risk assessments into account.

Video-sharing social media platforms like TikTok and Douyin have become a cultural trend among teen social media users. However, loss of privacy is a potentially serious downside of using such platforms. Despite the platforms' popularity among this age group, little is known about the ways teens manage their privacy on such social media platforms. By examining how teens' privacy risk perception and parental intervention shape three different aspects of privacy boundary management (i.e. privacy disclosure, privacy boundary linkage, and privacy boundary control), this study provides a comprehensive understanding of teen Douyin users' privacy management.

The purpose of this study is to explore the effects of recommendation algorithm, product reputation, new product novelty, privacy concern and privacy protection behavior on users’ satisfaction and continuance intention to use short-form video application (APP).

Based on the existing theories, the research model of this study was developed and 445 valid data were collected through a questionnaire survey. The partial least squares structural equation modeling (PLS-SEM) was employed for data analysis to test the research model and hypotheses.

The results reveal that the recommendation algorithm has a significant positive effect on user satisfaction, new product novelty and privacy concern. The influence of recommendation algorithm on privacy concern is negatively moderated by product reputation. Privacy concern has a significant and positive impact on privacy protection behavior, and privacy protection behavior has a significant and positive impact on user satisfaction. New product novelty also has significant impact on user satisfaction.

This study is one of the earliest studies to incorporate recommendation algorithm as a construct into the college students’ continuance intention to use short-form video APP. The influence of reputation as a moderator variable on the relationship between algorithm and privacy concerns is also investigated.