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This paper aims to provide a new drilling entry board for printed circuit board (PCB) process, superior in heat dissipation, lubrication, water solubility and hole location accuracy, achieving an excellent drilling process.

Using a mixture of polyethylene glycol (PEG) and water-soluble adhesives as hydrosoluble, endothermic and lubricant resins and aluminum foils as baseplates, a series of coated and aluminous entry boards (CABs) for PCB drilling was successfully prepared. The surface appearance of the entry boards was observed clearly by scanning electron microscopy (SEM). The endothermic and lubricant effects of the resins applied on the CABs was characterized by differential scanning calorimetry (DSC) and their water solubility was tested in the normal-temperature water (25°C). Moreover, the CABs’ good drilling properties were tested when they were used for PCB drilling.

The SEM analysis showed that the surfaces of the resin layers coated on the CABs whose coating thicknesses were less than 80 μm were smoother and flatter, which could improve hole location accuracy and reduce drill breakage ratio. By virtue of DSC, the endothermic and lubricant effects of the CABs were proven. The fusion of PEG in the resin layers could absorb the heat produced by drilling, restrain the temperature of the drill bit and hole rising and lubricate the drill bit efficiently when a hole was being drilled, which could achieve high-quality holes with good production efficiency. The water-soluble test showed that the prepared CABs had excellent water solubility at normal temperature, enabling the resin left on the hole walls and in the flute of the drill bit to be washed away easily and thereby improving the drilling efficiency and quality. The drilling tests showed that the increase in the thickness of the CABs’ coating could improve the hole location accuracy and alleviate the bit wear. In addition, the suitable coating thickness could ensure the firm adhering of the resin coating the aluminum foil, effectively avoid drill intertwist and prevent the resin debris from blocking the drilled holes on the surface of the entry board, which could hinder chip removal, resulting in poor hole wall quality and drill breakage.

This paper has a remarkably high industrial practicality in the PCB manufacture process.

Pesticide residue is a stubborn problem affecting the quality and safety of agricultural products in China, and has not yet been fundamentally resolved. The purpose of this paper is to study farmers' perception of pesticide residues, as well as the main factors affecting their perception from the viewpoint of farmers. Additionally, this research attempts to explore the basic characteristics of pesticide residues arising in the process of producing agricultural products under the prevailing policy background, so as to provide decision‐making references for the Chinese government to deepen the security management system of agricultural products.

The structural equation model (SEM) is an analytical tool for the observation and treatment of latent variables that are difficult to observe directly, and for the consideration of inevitable errors. This paper investigates the main factors affecting farmers' perception of pesticide residues in the investigated regions based on the SEM and samples of 241 farmers in six counties (cities and regions) of three districts in the Jiangsu Province of China.

According to the research, regional difference, farmers' gender, age, years of education, pesticide training and their own demand for safe agricultural products had different influences on their perception of pesticide residues. Additionally, it was difficult to measure the influence of family characteristics on farmers' perception of pesticide residues. Although the present paper only shows a preliminary study, its conclusion provides a reference value for the Chinese government to deepen the reform of the quality and safety regulatory system of agricultural products.

There are many similar studies in overseas countries, but the application of SEM in the study of the main factors affecting farmers' perception of pesticide residues has not been completely reported previously in domestic literatures. The research assumption of this paper has practically verified that corresponding research conclusions of foreign scholars in this field have universality in China.

This paper seeks to present an inertial motion tracking system for monitoring movements of human upper limbs in order to support a home‐based rehabilitation scheme in which the recovery of stroke patients' motor function through repetitive exercises needs to be continuously monitored and appropriately evaluated.

Two inertial sensors are placed on the upper and lower arms in order to obtain acceleration and turning rates. Then the position of the upper limbs can be deduced by using the kinematical model of the upper limbs that was designed in the previous paper. The tracking system starts from inertial data acquisition and pre‐filtering, followed by a number of processes such as transformation of coordinate systems of sensor data, and kinematical modelling and optimization of position estimation.

The motion detector using the proposed kinematic model only has drifts in the measurements. Fusion of acceleration and orientation data can effectively solve the drift problem without the involvement of a Kalman filter.

The image rendering is not undertaken when the data sampling is performed. This non‐synchronization is applied in order to avoid the breaks in the continuous sampling.

This new motion detector can work in different environments without significant drifts. Also, this system only deploys two inertial sensors but is able to estimate the position of the wrist, elbow and shoulder joints.

In order to improve the robustness to noise in point cloud plane fitting, a combined model of improved Cook’s distance (ICOOK) and WTLS is proposed by setting a modified Cook’s increment, which could help adaptively remove the noise points that exceeds the threshold.

This paper proposes a robust point cloud plane fitting method based on ICOOK and WTLS to improve the robustness to noise in point cloud fitting. The ICOOK to denoise the initial point cloud was set and verified with experiments. In the meanwhile, weighted total least squares method (WTLS) was adopted to perform plane fitting on the denoised point cloud set to obtain the plane equation.

(a) A threshold-adaptive Cook’s distance method is designed, which can automatically match a suitable threshold. (b) The ICOOK is fused with the WTLS method, and the simulation experiments and the actual fitting of the surface of the DD motor are carried out to verify the actual application. (c) The results shows that the plane fitting accuracy and unit weight variance of the algorithm in this paper are substantially enhanced.

The existing point cloud plane fitting methods are not robust to noise, so a robust point cloud plane fitting method based on a combined model of ICOOK and WTLS is proposed. The existing point cloud plane fitting methods are not robust to noise, so a robust point cloud plane fitting method based on a combined model of ICOOK and WTLS is proposed.

Purpose: The study aims to analyse and discuss the effect of COVID-19 on businesses. The chapter discusses the various machine learning (ML) tools and techniques, which can help in better decision making by businesses in the present world.

Need for the Study: COVID-19 has increased the role of VUCA elements in the business environment, and there is a need to address the challenges faced by businesses in such environment. ML and artificial learning can help businesses in facing such challenges.

Methodology: The focus and approach of the chapter are in the context of using artificial intelligence (AI) and ML techniques for decision making during the COVID-19 pandemic in a VUCA business environment.

Findings: The key findings and their implications emphasise the importance of understanding and implementing AI and ML techniques in business strategies during times of crisis.

Practical Implications: The chapter’s content is in the context of using AI and ML techniques during the COVID-19 pandemic and in a VUCA business environment.

This chapter focusses on the links between economic ideas, sustainability and the circular economy. Economics begins with the view that all resources are scarce and careful and informed choices must be made to ensure resources are used efficiently and not wasted. Given the fundamental importance of markets to human resource allocation decisions, unless economic concepts, especially markets and prices, are used to help transition towards the circular economy, a sustainable economic growth process is unlikely to be achieved. Economists have long grappled with the problems of resource depletion, unsustainable growth and intergenerational equity. Their ideas and views about the interconnection between markets, the environment and resource use have been in existence for several centuries. While frequently overlooked, some of these ideas have important insights for sustainable development and the implementation of a circular economy. The chapter will consider how economic concepts could be used to help society transition to a circular economy. It will also argue that difficulties with the implementation of a circular economy lie less with the application of economic instruments, and more with the political and institutional constraints that reduce our ability to think creatively and innovatively about ‘cradle-to-cradle’ processes.

This study investigates the convergence-of-interest and entrenchment effects on the relationship between managerial ownership and financial distress using evidence from the Chinese stock market. It also analyzes whether the relationship is mediated by research and development (R&D) investment.

Using a dataset consisting of 19,059 firm-year observations of Chinese listed companies in the Shanghai and Shenzhen Stock Exchanges between 2010 and 2020, this study employs both piecewise and curvilinear models.

The results indicate that managerial ownership has a negative association with firm financial distress in both the low (below 12%) and high (above 18%) convergence-of-interest regions of managerial ownership, suggesting that managerial ownership in this region may contribute to improve firm financial status. Meanwhile, managerial ownership has a positive association with firm financial distress in the entrenchment region (12–18%), implying that managerial ownership in the entrenchment region may contribute to impair firm financial status. Furthermore, the results show that R&D investment mediates the association between managerial ownership and financial distress.

This study is the first to provide evidence of a nonlinear relationship between managerial ownership and financial distress, and identify the entrenchment region in the Chinese setting.

A large, uneven settlement that is unfavourable to dam safety can occur between a concrete cut-off wall and the high-plasticity clay of earth core dam built on alluviums. This issue has been often studied using the small-strain finite element (FE) method in previous research. This paper aims to research the interaction behaviour between a concrete cut-off wall and high-plasticity clay using large-deformation FE analyses.

The re-meshing and interpolation technique with a small-strain (RITSS) method was performed using an independently developed program and adopted for large-deformation FE analyses, and a suitable element size for the high-plasticity clay region was suggested. The layered construction process of an earth core dam built on thick alluviums was simulated using the RITSS method incorporating a hyperbolic model for soil.

The RITSS method is an effective technique for simulating the soil–structure interaction during dam construction. The RITSS analysis predicted a higher maximum principle stress of the concrete cut-off wall and higher stress levels in the high-plasticity clay region than small-strain FE analysis.

A practical method for large-deformation FE analysis was advised and was used for the first time to study the interaction between a concrete cut-off wall and high-plasticity clay in dam engineering. Large deformation in the high-plasticity clay was handled using the RITSS method. Moreover, the penetration process of the concrete cut-off wall into the high-plasticity clay was captured using a favourable element shape and mesh density.