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This paper seeks to investigate work on silver sulphide formed on the surface of silver metal which was exposed to an environment containing sulphur contamination.

Laboratory tests were performed to determine the effect of the surface state, relative humidity, temperature and illumination.

It was indicated that sulphuration of silver was accelerated by mechanical polishing and illumination. The exposure was performed at 0, 54, 75 per cent relative humidity (rH) and at 16, 25, 37, 47 and 57°C. The tarnish rate at 54 per cent rH was more than two times than that at 0 per cent rH or 75 per cent rH, and the rate increased as a function of temperature.

A tarnish model was proposed. The tarnish reaction of silver is chemical reaction controlled, which is in accordance with the result deduced from the model.

The interaction between the silver powder and organic vehicle largely determines the rheological behavior of silver conductive paste. This study aims to prepare silver conductive paste with an organic vehicle system consisting of ethyl cellulose (EC) and terpineol/butyl carbitol acetate solvent mixtures. The study also aims to measure the rheological behaviors of the silver conductive pastes with different solvent mixtures, EC molecular weights and silver content, to investigate the interaction among the polymer, solvent and silver powder and determine the main factors affecting the thixotropic index and maximum silver content.

The rheological behaviors of silver conductive pastes with different solvent mixtures, EC molecular weights and silver content were investigated using viscometer.

The shear thinning became significant with increasing EC molecular weight. The EC solvation with higher molecular weight in solvent is better than that of EC with lower molecular weight. This leads to a stronger interaction between the silver powder and EC with higher molecular weight and consequently good silver particle dispersion. The relative viscosity of silver conductive paste at 10 s⁻¹ increases significantly with increasing silver content, but the relative viscosity at 100 s⁻¹ is much less sensitive to the silver content. The viscosities at low and high shear rate can be increased by increasing the silver content and EC molecular weight, respectively.

The interaction among the polymer, solvent and silver powder was investigated for the silver paste with high solid content. The main factors affecting the viscosities at high and low shear rates, thixotropic index and maximum silver content were determined.

It is a challenge to print a model with the size that is larger than the working volume of a three-dimensional (3D) printer. The purpose of this paper is to present a feasible approach to divide a large model into small printing parts to fit the volume of a printer and then assemble these parts into the final model.

The proposed approach is based on the skeletonization and the minima rule. The skeleton of a printing model is first extracted using the mesh contraction and the principal component analysis. The 3D model is then partitioned preliminarily into many smaller parts using the space sweep method and the minima rule. The preliminary partition is finally optimized using the greedy algorithm.

The skeleton of a 3D model can effectively represent a simplified version of the geometry of the 3D model. Using a model’s skeleton to partition the model is an efficient way. As it is generally desirable to have segmentations at concave creases and seams, the cutting position should be located in the concave region. The proposed approach can partition large models effectively to well retain the integrity of meaningful parts.

The proposed approach is new in the rapid prototyping field using the model skeletonization and the minima rule. Based on the authors’ knowledge, there is no method that concerns the integrity of meaningful parts for partitioning. The proposed method can achieve satisfactory results by the integrity of meaningful parts and assemblability for most 3D models.

The purpose of this paper is to investigate the relationship between union practices and two types of employees’ extra-role behaviors, namely, union citizenship behavior (UCB) and employee voice (EV), and the mechanisms that mediate this relationship.

Using matched data from 46 union leaders and 279 union members of 33 workplaces in China, this study utilized multilevel structural equation modeling to test the cross-level influences of union practices on employees’ extra-role behaviors and the mediation effects.

The results show that (1) union practices have a positive impact on employees’ UCB and EV, and (2) union practices increase UCB and EV through the improvement of industrial relations (IR) climate at the workplace level, as well as union commitment (UC) and union instrumentality (UI) at the individual level.

Although the authors collected data from multi-sources (i.e. union leaders and members), the cross-sectional data of this study limited the ability to make casual inferences.

This study contributes to the literature by providing theoretical explanation and empirical evidence to illustrate the role of union practices in increasing the extra-role behaviors of employees (i.e. UCB and EV). This is of particular importance in elaborating the effectiveness of enterprise unions under the recent reforms in China. In addition, the authors also unpacked the antecedents of extra-role behaviors in the union context by investigating how IR climate, UC and UI mediate the relationship between union practices and extra-role behaviors of employees.

Traditional simulation research of geological and similar engineering models, such as landslides or other natural disaster scenarios, usually focuses on the change of stress and the state of the model before and after destruction. However, the transition of the inner change is usually invisible. To optimize and make models more intelligent, this paper aims to propose a perceptible design to detect the internal temperature change transformed by other energy versions like stress or torsion.

In this paper, micron diamond particles were embedded in 3D printed geopolymers as a potential thermal sensor material to detect the inner heat change. The authors use synthetic micron diamond powder to reinforced the anti-corrosion properties and thermal conductivity of geopolymer and apply this novel geopolymer slurry in the direct ink writing (DIW) technique.

As a result, the addition of micron diamond powder can greatly influence the rheology of geopolymer slurry and make the geopolymer slurry extrudable and suitable for DIW by reducing the slope of the viscosity of this inorganic colloid. The heat transfer coefficient of the micron diamond (15 Wt.%)/geopolymer was 50% higher than the pure geopolymer, which could be detected by the infrared thermal imager. Besides, the addition of diamond particles also increased the porous rates of geopolymer.

In conclusion, DIW slurry deposition of micron diamond-embedded geopolymer (MDG) composites could be used to manufacture the multi-functional geological model for thermal imaging and defect detection, which need the characteristic of lightweight, isolation, heat transfer and wave absorption.

The purpose of this study is to examine the mechanism of benevolent leadership on employee cheating behavior through two paths – employee uncertainty and perceived acceptability of norm violation – and also reveal the possible dark side of benevolent leadership. Meanwhile, the moderating effects of leader behavioral integrity in the cognition dual path process are also discussed.

This study invites 383 employees and their superiors in seven Chinese enterprises as the research objects and conducts a paired survey at three time points, and then Mplus 7.4 software is used to analyze the empirical data.

The results are shown as follows. Benevolent leadership plays a positive role on uncertainty and perceived acceptability of norm violation. Uncertainty and perceived acceptability of norm violation mediate the relationship between benevolent leadership and cheating behavior, respectively. Leader behavioral integrity moderates the positive role of benevolent leadership on uncertainty and perceived acceptability of norm violation. Leader behavioral integrity moderates the indirect effect of benevolent leadership on employees' cheating behavior through uncertainty and perceived acceptability of norm violation.

This study reveals the mechanism behind the negative role of benevolent leadership through the cognition reaction of employees to benevolent leadership and broadens the research scope of benevolent leadership. Meanwhile, it provides some practical inspiration for leaders to effectively use the benevolent leadership style and restrain employees' cheating behavior.

An electrochemical method based on the open circuit potential (OCP) fluctuations was put forward. It can be used to optimize the alloy compositions for improving the corrosion resistance of rust layer.

The potential trends and potential fluctuations of carbon steels in seawater were separated by Hodrick–Prescott filter. The Spearman correlation coefficient and max information coefficient were used to explore the correlation of alloy compositions and potential fluctuations.

After long-term immersion, potential fluctuation resistance (PFR) can be used to characterize the corrosion resistance of metals and its rust layers. In the 1,500 to 2,500 h exposure period, Fe, C and S compositions have strong negative correlations, whereas PFR and P composition have weak negative correlations. Mn, Cu and Ti alloy compositions help the rust layer of carbon steels have higher PFRs. These elements that exhibit higher PFRs in this period have been confirmed to have the effect on improving the corrosion resistance of rust layer.

A new computing method for alloy composition optimization of carbon steels based on the OCP fluctuations was put forward. This method combines electrochemical monitoring with the long-term actual seawater environmental tests of various carbon steels.

As fertile soil for product promotion, online interest communities have gradually come into brands' view. However, existing research does not clarify whether brand engagement in consumer interaction is beneficial to the development of online interest communities. This study attempts to investigate the effects of brand engagement on the online interest community operation.

The authors propose a model that delineated the influence of brand engagement on consumers' citizenship behavior in the online interest community from the commitment-trust perspective. Scenario-based experiments were conducted and 536 data were collected by simple random sampling.

Results shows that a stronger perception of brand engagement has a positive influence on the relationship (trust and commitment) between the community and its users, which further influences online community citizenship behavior (feedback, advocacy and tolerance) of both posters and lurkers, especially for the posters. Although relationships are more complex, brand engagement activates the development of online interest communities to some extent.

This original study contributes to the commitment-trust theory by examining the impact of brand engagement on citizenship behavior via community commitment and trust in the online interest community context. In addition, this study compares the moderating effect of posters vs lurkers on the relationship between brand engagement and citizenship behavior in the online interest community.

The study aims to explore the composition and microstructure of clay functionally graded materials under the process of double-gradient direct ink writing (DIW).

The investigation focused specifically on the pore characteristics of barite-kaolin clay composite after three-dimensional (3D) printing and sintering as well as its bionic application in geophysical model.

The model with pore and material variations brought about spatial and nonlinear mechanical properties. Moreover, the vertical gradient and connected pores in the upper kaolin part simulated the natural phenomenon of the landslide model (take Chinese Majiagou landslides as an example). Both the thermal debinding behavior and the kaolin powder particles characteristics [large pore volume (0.019 cm³g^–1) and pore size (29.20 nm)] were attributed to the interconnection channels.

Hence, the macroscopic and microscopic pores achieved by dual-gradient DIW process make it possible to control the permeability and details of properties, precisely in the geological model.

Drawing upon institution-based trust theory, the purpose of this paper is twofold: firstly, to examine the joint influences of legally binding and market-driven institutional mechanisms in promoting customers’ trust and continuance intention in the ridesharing platform; and secondly, to examine if there exists a trust transfer mechanism between institution-based trust and interpersonal trust.

An online survey was conducted in China and data were collected from 307 customers in DiDi, which is one of the largest ridesharing platforms in China. Structural equation modeling statistical method was used to test the theoretical model and research hypotheses.

The empirical results suggest that market-driven institutional mechanisms, regarding feedback and surge pricing, have strong influences on customers’ trust in the ridesharing platform. In addition, legally binding institutional mechanisms, regarding payment security and driver certification, are also beneficial to promote customers’ trust. Furthermore, there is a trust transfer between customers’ trust in the platform and trust in the driver.

This study provides guidelines to the administrators of the ridesharing platform to establish effective institutional mechanisms. In particular, the platform can appropriately adopt and implement the legally binding mechanisms combined with market-driven mechanisms on the platform, in order to enhance customers’ trust and promote their subsequent transaction behaviors.

This study enriches and extends the extant literature of institution-based trust from e-commerce to the sharing economy by identifying four significant institutional mechanisms. Furthermore, this study presents a new perspective of customer trust (one-to-many) in the context of ridesharing and uncovers the transfer mechanism between institution-based trust and interpersonal trust.