This study presents a parylene-based trench isolation (PBTI) method using standard silicon wafer to obtain a suspended MEMS structure. The silicon-based suspended structures were electrically isolated using supported parylene beams. The parylene beams provide electrical isolation between the suspended structure and substrate, and prevent anchor movement during actuation and wire-bonding. The proposed process is a simple low-temperature, dry- etching and reliable fabrication method for structure creation and electrical isolation and does not require wet-release, LPCVD, plasma-enhanced chemical vapor deposition (PECVD), ion implantation, sputtering process, or sandwiched oxide/polysilicon/metal isolation. The parylene beams were created by performing multiple steps of parylene deposition and removal inside a silicon mold. The trench etching, polymer deposition for sidewall protection, floor polymer removal, structure release, and polymer stripping steps were completed by modifying the etching or passivation steps of the Bosch process.

Abstract The petrochemical and chemical industries are widely regarded as process industries with significant hazards. Investigations of numerous accidents have shown that over half are caused by equipment failures. Proper management of Safety‐Critical Equipment (SCE) related to major hazards and ensuring their functional integrity can significantly reduce the occurrence of Process Safety Management (PSM) accidents. There are currently many risk assessment technologies available to provide a foundational basis for SCE identification, although each method has its limitations. In 2016, the Center for Chemical Process Safety (CCPS) published guidelines for asset integrity (CCPS, 2017), outlining the process for determining SCE, offering a practical identification approach to the industry. However, the principles of this method are broad, and its practical implementation remains unclear. Therefore, this paper discusses how to integrate various risk assessment methods and develop a feasible procedure for SCE identification in practice. It highlights the need to link identified SCEs to corresponding safety‐critical tasks to ensure the functional integrity of the equipment.

PurposeIn recent years, community-based tourism (CBT) in the global market has been combined with specific themes in order to establish various tourism activities. Relatively few studies have comprehensively investigated how this type of CBT should be developed. Therefore, this study takes CBT with festival themes combined with community characteristics as a case study, which explores what obstacles exist in CBT with a combination of community characteristics – the industrial history of sugar factories and external themes, such as, formal flower displays.Design/methodology/approachThe thematic analysis is employed for data analysis of interviews. All interview participants were stakeholders.FindingsThis study identifies five types of obstacles: policy-related, environmental-related, innovation-related, industry-related and communication-related. Based on these findings, it is vital to consider both community and other characteristics of CBT. At the same time, after evaluating the rational perceptions of different stakeholders within the same type of obstacle, this study proposes a more specific and comprehensive development strategies for CBT.Originality/valueTo the best of the authors' knowledge, this is the first study of community agricultural tourism which collected the viewpoints of different stakeholders – tourists, residents, community associations, local businesses and the government. This study employs in-depth analysis of external policies and environmental and agricultural factors to discover and develop relevant coping strategies and implications.

This study synthesized CaAl2O4:Eu2+ blue phosphors using the sol-gel method. The effects of incorporating citric acid, poly (oxyethylene) (PEG), and HCl in the precursor on the luminescent properties of phosphors were investigated. No significant changes were observed in the photoluminescence (PL) spectra of the phosphors when different precursor solutions were used. However, the use of PEG and citric acid led to a noticeable decrease in the PL intensity. Notably, the use of HCl resulted in an increase in PL. In addition, upon heating the phosphors from room temperature to 110 °C, the PL spectrum remained unchanged, whereas the PL intensity decreased linearly with increasing temperature. This indicated the suitability of CaAl2O4:Eu2+ for optical temperature-sensing applications.

Metal foundries still rely heavily on crucible furnaces. The current furnace design, which is currently being used by the partner industry, has been found to be not properly designed and will result in a reduction in efficiency. CFD simulation will be used to find the optimal melting furnace design. This research simulation consists of 3 stages: pre-processing, solving, and post-processing. There are two furnace geometries, cylindrical and hexagonal, while the burner location will be divided into 3 positions, namely P1, P2, and P3. The most optimal furnace design will be used as a basis for the verification testing process. The process of comparing the old and the new smelting furnace design is carried out to understand the performance and characteristics of each furnace. The simulation results for the average crucible temperature in the cylindrical furnace were obtained as follows: 288.5 ºC for the P1 burner, 306.2 ºC for the P2 burner, and 284.5 ºC for the P3 burner. Meanwhile, the simulation results show that the average crucible temperature value in the hexagonal furnace is 290.0 ºC for the P1 burner, 281.6 ºC for the P2 burner, and 237.8 ºC for the P3 burner. The verification testing process produced an average crucible temperature value of 237.5 ºC. Furthermore, the comparison test from the old and new furnace designs to melt 2.5 kg of aluminium at 680 ºC with the old furnace took approximately 30 minutes and 33 minutes with the new furnace. The new furnace produced much more uniform melting than the old furnace.

In the Laser Powder Bed Fusion (L-PBF) process, 3D components with complex geometries are fabricated in a layer-by-layer fashion by using a controlled laser beam to selectively melt particular regions of the metal powder bed. However, due to the stochastic nature of the L-PBF process, the top surface roughness of each solidified layer tends to be different even when the optimal processing conditions for the different positions on the build plate are employed. As a result, the mechanical properties of the built components frequently vary from one component to the next. Accordingly, this study proposes an Intelligent Additive Manufacturing Architecture (IAMA) for controlling the surface roughness of each build layer through an appropriate adjustment of the laser re-melting parameters. The IAMA architecture comprises five modules, namely In-Situ Metrology (ISM), Ex-Situ Metrology (ESM), Automatic Virtual Metrology (AVM), Additive Manufacturing Simulation (AMS) and Intelligent Compensator (IC). The feasibility of the proposed architecture is demonstrated by comparing the top surface roughness of cubic and mechanical strengths of tensile test samples built using the proposed method with those built using a traditional L-PBF approach without surface roughness control. It is found that the samples fabricated using the IAMA approach have an average top surface roughness of 1.6 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu$</tex-math> </inline-formula> m and a standard deviation is 0.7 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu$</tex-math> </inline-formula> m. By contrast, the samples produced using the traditional L-PBF approach have an average surface roughness of 13.45 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu$</tex-math> </inline-formula> m and a standard deviation of 2.5 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu$</tex-math> </inline-formula> m. In addition, the specimens produced with the assistance of IAMA architecture have an average tensile strength of 1013 MPa with a standard deviation of 69.5 MPa, while those printed without surface roughness control have an average tensile strength of 903 MPa with a standard deviation of 101.4 MPa <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Note to Practitioners</i> —As L-PBF produce part in a layer-by-layer manner, therefore, the roughness on the top surface of previous layer have a strong influence on the printing quality of current layer. The variations of surface roughness will lead to the fluctuation of mechanical properties of the fabricated components. Additionally, to the best of author’s knowledge, current commercial L-PBF machines can not actively control the surface roughness of samples during the process. The proposed IAMA in this work can predict and control the roughness on the top surface of each layer during L-PBF process. Therefore, the constructed architecture has strong potential for integrating into the commercial L-PBF machine for controlling the surface roughness on the top of the parts during the manufacturing process. As a result, the quality of the fabricated components is expected to be in consistent. Accordingly, L-PBF machine equipped with IAMA will have a strong potential in applying for mass production of the components in aerospace and automobile industries.