Conceptual design of a web-based LNG plant management system through adoption of the integrated environment for design and maintenance

The present paper aims to suggest a web-based LNG (Liquefied natural gas) plant management system that is applicable from the design stage through the operational lifetime of the plant. The usefulness of this program is maximized by combining a virtual plant and RAMS (Reliability, availability, maintainability and safety). To achieve this goal, principles related to a virtual plant and RAMS are reviewed and several modules were designed. In particular, the RBI (Risk based inspection) module based on the API (American Petroleum Institute) code was developed for implementing RAMS. To review the design and deliver geometrical information regarding the system and processes, several commercial softwares are chosen to develop the navigator module and virtual module of LPMS-RAMS (LNG Plant Management System based on RAMS). Also, several modules related to maintenance and safety, are developed. It means that the LPMS-RAMS has many applicable modules based on the concept of virtual plant and RAMS. Especially, The VR (Virtual reality) module in this system will be useful during the design stage for diverse types of LNG plants. Also, the RAMS module is expected to improve the efficiency and safety of the LNG plant during its operation.     

Effect of a high-temperature pre-bake treatment on whisker formation under various thermal and humidity conditions for electrodeposited tin films on copper substrates

The effect of high-temperature pre-bake treatment on whisker formation was studied under various thermal and/or humidity and plating conditions for thin tin films on thick copper substrates. The pre-bake treatment was performed at 180 °C for 1 h. In tests conducted at 85 °C/85% relative humidity and ambient atmosphere, whisker formation was suppressed considerably when a pre-bake treatment was applied. After the pre-bake treatment, Cu₃Sn intermetallic compounds were formed at the tin-copper interface. Cu₃Sn IMCs play an important role in the formation of regular-shaped Cu₆Sn₅. Cu₃Sn IMCs were also formed after temperature cycling and under conditions of 85 °C/85% RH. Irregular-shaped Cu₆Sn₅ IMCs were formed under all test conditions except for pre-baked samples in ambient atmosphere. A pre-bake treatment at 180 °C is advantageous for the inhibition of whisker formation and allows for planar and regular-shaped Cu₃Sn to be produced.     

Methods for in-cylinder EGR stratification and its effects on combustion and emission characteristics in a diesel engine

The effects of in-cylinder EGR stratification on combustion and emission characteristics are investigated in a single cylinder direct injection diesel engine. To achieve in-cylinder EGR stratification, external EGR rates of two intake ports are varied by supplying EGR asymmetrically using a separated intake runner. The EGR stratification pattern is improved using a 2-step bowl piston and an offset chamfer at the tangential intake port. When high EGR gas is supplied to the left (tangential) port, a high EGR region is formed at the central upper region of the combustion chamber. Consequently, combustion is initiated in the low EGR region, and PM is reduced significantly. When high EGR gas is supplied to the right (helical) port, a high EGR region is formed at the lower periphery of the combustion chamber. Therefore, combustion is initiated in the high EGR region, and NO_x is reduced without PM penalty. Stratified EGR potentially reduces NO_x by maximum 45%, without penalties of performance and other emissions. A proper in-cylinder swirl with stratified EGR maximizes the effects and achieves simultaneous reduction of NO_x by 7% and PM by 23%. Moreover, the robustness of stratified EGR is evaluated under various operating conditions and injection strategies.     

Mining-based lifecare recommendation using peer-to-peer dataset and adaptive decision feedback

Due to the enhancing of life quality, increasing of chronic diseases, changing lifestyles, and an expanding life expectancy, rapid population aging requires a new business model that promotes happiness and emphasizes a healthy body and mind through the “anytime, anywhere well-being” lifestyle. Recently, lifecare systems using IoT devices are being released as products that are influential on the overall society, and their effectiveness is continuously proven. In addition, based on peer-to-peer (P2P) networking, diverse companies are conducting investments and research to develop devices as well as solutions that connect to these devices. Accordingly, in this study, a mining-based lifecare-recommendation method using a peer-to-peer dataset and adaptive decision feedback is proposed. In addition to collecting PHRs, the proposed method measures life-logs such as dietary life, life pattern, sleep pattern, life behavior, and job career; the P2P-dataset preprocessed index information; and biometric information using a wearable device. It uses the Open API to collect the health-weather and life-weather index data from public data, and it uses a smart-band-type wearable device known as a biosensor to measure the heart rate, daily activity, and body temperature. It monitors the current status and conditions through the classification of life data, and it mines big data and uses a decision tree to analyze the association rules and correlations, as well as to discover new knowledge patterns. In the peer-to-peer networking, a lifecare recommendation model that uses adaptive decision feedback has been developed for the peer-to-peer platform. This adaptive decision feedback reflects an individual’s importance or sensory level. Accordingly, it proposes more individualized and flexible results and can be configured to support intellectual lifecare. A mining-based lifecare-recommendation mobile service can also be developed to enhance the quality of life, as it provides user-based health management and reduces the medical expenses; accordingly, it enhances the service satisfaction and quality in the lifecare field.     

Corrosion properties of plasma-polymerized methylcyclohexane films using electrochemical methods

Three types of methylcyclohexane (MCH) coating were deposited as interlayer dielectrics on copper using plasma-enhanced chemical vapor deposition (PECVD) at three different RF plasma power levels. The coating performance was then evaluated by an electrochemical im pedance spectroscopy (EIS) and a potentiodynamic polarization test in 3.5 wt.% NaCl solution. An atomic force microscopy (AFM) and Fourier transform infrared reflection (FT-IR) spectroscopy were also conducted to analyze the coatings. The MCH coatings showed a lower corrosion rate than the copper substrate in the potentiodynamic tests. The EIS results showed that the corrosion resistance of the coatings increased with an increasing plasma power. Thus, the MCH films with an increasing plasma power improved the corrosion resistance due to the formation of a low-porosity coating, the enhanced formation of C−H, C−C, and C≡C stretching configurations, and the improved smooth surfaces.     

Mass balance research for high electrochemical performance direct methanol fuel cells with reduced methanol crossover at various operating conditions

Mass balance research in direct methanol fuel cells (DMFCs) provides a more practical method in characterizing the mass transport phenomena in a membrane electrode assembly (MEA). This method can be used to measure methanol utilization efficiency, water transport coefficient (WTC), and methanol to electricity conversion rate of a MEA in DMFCs. First, the vital design parameters of a MEA are recognized for achieving high methanol utilization efficiency with increased power density. In particular, the structural adjustment of anode diffusion layer by adding microporous layer (MPL) is a very effective way to decrease WTC with reduced methanol crossover due to the mass transfer limitation in the anode. On the other hand, the cathode MPL in the MEA design can contribute in decreasing methanol crossover. The change of structure of cathode diffusion layer is also found to be a very effective way in improving power density. In contrast, the WTC of DMFC MEAs remains virtually constant in the range of 3.4 and 3.6 irrespective of the change of the cathode GDL. The influence of operating condition on the methanol utilization efficiency, WTC, and methanol to electricity conversion rate is also presented and it is found that these mass balance properties are strongly affected by temperature, current density, methanol concentration, and the stoichiometry of fuel and air.     

Artificial intelligence enabled smart machining and machine tools

Journal of Mechanical Science and Technology - Artificial intelligence (AI) in machine tools offers diverse advantages, including learning and optimizing machining processes, compensating errors,...     

Smart card-based secure authentication protocol in multi-server IoT environment

Multimedia Tools and Applications - In recent years, the internet of things has been widely utilized in various fields, such as in smart factories or connected cars. As its domain of application...