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The purpose of this paper is to study the thermal warpage of a plastic ball grid array (PBGA) mounted on a printed circuit board (PCB) during the reflow process.

A thermal-mechanical coupling method that used finite-element method software (ANSYS 13.1) was performed. Meanwhile, a shadow moiré apparatus (TherMoiré PS200) combined with a heating platform was used for the experimental measurement of the warpage of PBGA according to the JEDEC Standard.

The authors found that the temperature profiles taken from the simulated results and experimental measurement are consistent with each other, only with a little and acceptable difference in the maximum temperatures. Furthermore, the maximum warpage measurements during the reflow process are 0.157 mm and 0.149 mm for simulation and experimental measurements, respectively, with a small 5.37 per cent difference. The experimental measurement and simulated results are well correlated. Based on the validated finite element model, two factors, namely, the thickness and dimension of PCB, are explored about their effect on the thermal warpage of PBGA mounted on PCB during the reflow process.

The paper provides a thorough parametrical study of the thermal warpage of PBGA mounted on PCB during the reflow process.

The findings in this paper illustrate methods of warpage study by combination of thermal-mechanical finite element simulation and experimental measurement, which can provide good guidelines of the PCB design in the perspective of thermal warpage during the reflow process.

To obtain a vascularized autologous bone graft by in-vivo tissue transformation, a biocompatible tissue transformation mold (TTM) is needed. An ideal TTM is of high geometric accuracy and X-ray radiolucent for monitoring the bone tissue formation. The purpose of this study is to present the TTM design and fabrication process, using 3D reconstruction, stereolithography (SLA) and silicone molding.

The rat mandible, the targeted bone graft, was scanned by micro-computed tomography (CT). From the micro-CT images, the 3D mandible model was identified and used as the cavity geometry to design the TTM. The TTM was fabricated by molding the biocompatible and radiolucent silicone in the SLA molds. This TTM was implanted in a rat for in vivo tests on its biocompatibility and X-ray radiolucency.

SLA can fabricate the TTM with a cavity shape that accurately replicates that of the rat mandible. The bone formation inside of the silicone TTM can be observed by X-ray. The TTM is feasible for in vivo tissue transformation for vascularized bone reconstruction.

Research of the dimensional and geometrical accuracy of the TTM cavity is required in the future study of this process.

The TTM fabricated in this presented approach has been used for in-vivo tissue transformation. This technique can be implemented for bone reconstruction.

The precision fabrication of the TTMs for in-vivo tissue transformation into autogenous vascularized bone grafts with complex structures was achieved by using SLA, micro-CT and silicone molding.

This paper aims to apply the heterogeneous autoregressive model of realized volatility (HAR-RV) model to minimum-variance hedge ratio estimation and compares the hedging performance of presenting a model with that of a conventional rolling ordinary-least-square (OLS) hedging model. Moreover, this paper empirically analyzes the relationship between hedging performance and the heterogeneity of investors with different trading frequency in forming the expectation for the spot volatility, futures volatility and the covariance in the market.

Use HAR-RV to form expectations of participants of spots and futures market for the next period volatility based on two parts. One is the current observable realized volatility at the same time scale. The other is the expectation for the next longer time scale horizon volatility. Compare hedging performance with rolling OLS model and HAR-RV model. Present a three-times-scale-length (daily, weekly and monthly) HAR-RV model for the spot and futures returns and volatility to analyze the relationship between the hedging performance and the heterogeneity among participants in each market.

The empirical results show that HAR-RV model outperforms the rolling OLS in terms of variance reduction and expected utility in the out-of-sample period. The results also indicate that the greater variance reduction occurs when investors with different trading frequency have a less heterogeneous expectation for spot volatility and more heterogeneous expectation for futures volatility and the covariance. In addition, the expected utility increases along with lower heterogeneity in spot volatility and higher in futures volatility and the covariance. Hedging performance improves along with decreasing heterogeneity of investors in spot volatility and increasing heterogeneity in futures volatility and the covariance.

This paper considers the heterogeneity of participants in spot and futures market, the authors apply HAR-RV model to MVHR estimation and compare the hedging performance of presenting a model with that of conventional rolling OLS hedging model, providing more evidence in hedging literature. This paper analyzes in depth the relationship between hedging performance and the heterogeneity in the market.

Express freight transportation is in rapid development currently. Owing to the higher speed of express freight train, the deformation of the bridge deck worsens the railway line condition under the action of wind and train moving load when the train runs over a long-span bridge. Besides, the blunt car body of vehicle has poor aerodynamic characteristics, bringing a greater challenge on the running stability in the crosswind.

In this study, the aerodynamic force coefficients of express freight vehicles on the bridge are measured by scale model wind tunnel test. The dynamic model of the train-long-span steel truss bridge coupling system is established, and the dynamic response as well as the running safety of vehicle are evaluated.

The results show that wind speed has a significant influence on running safety, which is mainly reflected in the over-limitation of wheel unloading rate. The wind speed limit decreases with train speed, and it reduces to 18.83 m/s when the train speed is 160 km/h.

This study deepens the theoretical understanding of the interaction between vehicles and bridges and proposes new methods for analyzing similar engineering problems. It also provides a new theoretical basis for the safety assessment of express freight trains.

Currently, rehabilitation medical care is expensive, requires a large number of rehabilitation therapist and which can only limit in the fixed location. In addition, there is a lack of research on the structure optimization and theoretical analysis of soft actuators for hand rehabilitation. In view of the problems above, this paper aims to propose a cheap, portable, wearable soft multiple joints rehabilitation glove.

First, this paper determined the hyperelastic constitutive model by material tensile test. Second, the soft actuator’s internal longitudinal section shape was optimized through the comparison of three diverse chamber structures. Meanwhile, the motion model of the soft actuator is established by the finite element model analysis method. Then, this paper established the constitutive model of the soft actuator according to the torque equilibrium equation and analyzed the relationship between the soft actuator’s bending angle and the input air pressure. This paper has verified that the theoretical model is correct through the soft actuator bending test. Finally, rehabilitation gloves were manufactured according to the model and the rehabilitation performance and grasping ability of gloves were verified through experiments.

The optimization results show that the internal semicircular cavity has better performance. Then, the actuator performance is better after adding the external arc structure and optimizing the physical dimension. The experimental results show that the trajectory of the actuator conforms to the mathematical model and rehabilitation gloves can meet the needs of rehabilitation treatment.

Rehabilitation gloves made of actuators can help patients with hand dysfunction in daily rehabilitation training. Then, it can also assist patients with some fine and complicated hand movements.

This paper proposes a new type of soft rehabilitation glove, which is composed of new soft actuators and adapting pieces. The new actuator is small enough to be fitted to the knuckle of the glove to move each joint of the finger.

This paper aims to confront the rising threat of deepfake videos, focusing on the limited research on deepfake detection strategies among seniors. The study thus investigates seniors’ video credibility conceptualizations and identifies their deepfake detection strategies.

This study employed semi-structured interviews with 20 seniors aged 55 to 70. Areas covered include their perceptions of video information credibility and identification strategies undertaken. Qualitative content analysis was conducted to interpret interview responses.

Seniors emphasized the importance of objectivity, trustworthiness, believability, reliability and truthfulness in terms of video credibility. Regarding strategies for assessing video credibility, seniors employed five categories: character appearance, non-human visuals, audio, personal knowledge and external sources.

This study contributes to the literature on human-oriented deepfake detection strategies by uncovering diverse methods employed by seniors. It enhances the understanding of how individuals assess video credibility in the context of deepfakes. Furthermore, this study offers practical and applicable strategies for real-world deepfake detection.

The handicraft sector is unorganized with huge potential for the economic upliftment of the bottom of the pyramid (BOP) craft producers. To ensure the sustainable livelihood of the artisans living in BOP, it is essential to identify the hurdles being faced by them so that they can be worked upon. This paper aims to look at the existing handicraft value chain in an integrated way to identify these hurdles and suggest probable solutions to mitigate them.

A two-stage study involving quantitative and qualitative approaches is used. Empirical observations from 218 artisans were analyzed using the relative to an identified distribution to rank the different variables affecting the functioning of the handicraft value chain. Next, 17 handicraft entrepreneurs were interviewed to identify solutions for the hurdles.

A two-stage study examining the perspectives of artisans and handicraft entrepreneurs identified five significant challenges affecting the handicraft sector and viable solutions to address them. While presenting an operational model, a comprehensive picture of the handicraft business ecosystem was studied, from the procurement of raw materials to the marketing and sale of finished products. This can assist handicraft producers in sustaining their livelihoods and expanding the industry.

Studies on the handicraft value chain at BOP are rare, and none have tried to look at the sector holistically to find solutions and propose an operational framework. The study has captured the voices of the artisans and handicraft entrepreneurs and, through a mixed-method approach, identified the main pain points of the BOP artisans to arrive at a workable solution for better business outcomes.

The purpose of this paper is to empirically test a research model that incorporated antecedents of praise feedback behaviour (fear of confrontation and incentive for reducing nuisance costs), praise feedback behaviour (deliberatively praise feedback, casual praise feedback, and true compliment feedback) and consequences (trust and repurchase intention).

A structural equation model was employed to test the relationships of the research model using survey data collected from 398 Taobao consumers.

The results showed that fear of confrontation and incentive for reducing nuisance costs had a significant positive influence on deliberatively praise feedback and true compliment feedback, respectively, and both antecedents had a significant positive influence on casual praise feedback of consumers. It also showed that trust was influenced negatively by deliberatively praise feedback, and positively by casual praise feedback and true compliment feedback. Meanwhile, deliberatively praise feedback and true compliment feedback were found to have negative and positive influences on repurchase intention, respectively.

This research was a pilot study to identify a three-dimension conceptualization of praise feedback behaviour from the perspective of customer satisfaction, and to understand positive review bias from the perspective of input processes.

The study of mindfulness is still shown to be of interest in different aspects of organisations and/or businesses. Therefore, this study aims to present an integrative, multi-level model of mindfulness based on a holistic approach that can contribute to better governance practices and lead to competitive advantages.

To fulfil this aim, an extensive integrative review of the literature, from the main articles about this topic, was made.

This study shows that the concept of mindfulness, a conscious presence or full attention and its relation with organisations or firms’ personal, behavioural and social characteristics, in the current context of great adversity, uncertainty and unpredictability, is of interest at the individual, organisational and social level.

This conceptual study has important implications for both practice and theory. It demonstrates that mindfulness significantly impacts the manager/business person’s ecosystem at the individual, organisational and social levels, particularly in relation to Sustainable Development Goals.

This study introduces a comprehensive theoretical model that explains this relationship and organises information from a multi-level perspective. This approach can contribute to the advancement of theory by clarifying and discussing the role of mindfulness at the individual, organisational and societal levels. It also identifies opportunities and outlines future research directions, aiming to promote more sustainable development.