This study is to observe the exact behavior of anisotropic conductive adhesion (ACF) package under humid environments by obtaining the moisture-induced properties such as diffusion coefficient (the rate of moisture movement into the materials), saturated moisture content (the maximum absorbed quantity), and swelling coefficient (length change due to the chemical interaction). So the experiments were performed to get the moisture-induced properties of ACF and FR4 using newly developed method at various temperature and relative humidity conditions. Experimental results showed that the diffusion coefficient of ACF and FR4 follows Arrhenius’ equation very well, and the saturated moisture content of them follows Henry’s law, which means linear relationship between saturated moisture content and relative humidity, but the saturated moisture content of ACF is influenced by temperature as well as relative humidity. And the swelling coefficient of ACF and FR4 increases with temperature. Especially in the case of ACF, it shows the dramatic degradation due to $Tg$ (glass transition temperature) at nearby $85°C$. Finally, as using these experimental results, the behavior of the ACF package under humid environment is predicted through finite element simulation. When wetness defined by moisture content over saturated moisture content changes from 0 to 0.9, the center of the ACF package is subject to compression and the edge of the ACF package is subject to tension in the case of transient state. After all, because the edge of the ACF package is very weak due to bending moment, the failure is easy to occur under humid environment.

In this study, we propose a module-type triboelectric nanogenerator (TENG) capable of harvesting electricity from a variety of mechanical energy sources and generating power from diverse forms that fit the modular structure of the generator. The potential energy and kinetic energy of water are used for the rotational motion of the generator module, and electricity is generated by the contact/separation generation mode between the two triboelectric surfaces inside the rotating TENG. Through the parametric design of the internal friction surface structure and mass ball, we optimized the output of the proposed structure. To magnify the power, experiments were conducted to optimize the electrical output of the series of the TENG units. Consequently, outputs of 250 V and 11 μA were obtained when the angle formed between the floor and the housing was set at 0° while nitrile was set as the positively charged material and the frequency was set at 7 Hz. The electrical signal generated by the module-type TENG can be used as a sensor to recognize the strength and direction of various physical quantities, such as wind and earthquake vibrations.

In this study, we propose a module-type triboelectric nanogenerator (TENG) capable of harvesting power from a variety of mechanical energy sources. The potential energy and kinetic energy of water are used for the rotational motion of the generator module, and electricity is generated by the contact/separation generation mode between the two triboelectric surfaces inside the rotating TENG. Through the parametric design of the internal friction surface structure and mass ball, we optimized the output of the proposed structure. To magnify the power, experiments were conducted to optimize the electrical output of the series of TENG units. The electrical signal generated by the module-type TENG can be used as a sensor to recognize the strength and direction of various physical quantities, such as wind or earthquake vibrations.

When designing a hand caliber with a high-temperature, high-pressure internal fluid transport pipe, reliability, safe use, and performance must be considered. Reliability refers to the stress caused by thermo-mechanical load; safe use refers to the low-temperature burns that might occur upon contact, and high-temperature burns caused by gas leakage occurring in the cylinder gap; and performance refers to projectile velocity. In this study, numerical simulation methods for heat transfer, structure analysis, and gas leakage are proposed so that solutions can be designed to account for the above three criteria. Furthermore, a hand-caliber design guide is presented. For heat transfer and structural analysis, mesh size, the transient convective heat transfer coefficient, and boundary conditions are described. Regarding gas leakage, methods reflecting projectile motion and determination of the molecular weight of the propellant are described. As a result, a designed hand caliber will have a high reliability, because the thermo-mechanical stress is lower than the yield stress. There will be little risk of low-temperature burns, but there will be a high temperature-burn risk, owing to gas leakage in the cylinder gap. The larger the cylinder-gap size, the greater the gas leakage and the smaller projectile velocity. The presented numerical simulation method can be applied to evaluate various aspects of other structures that require high-temperature, high-pressure fluid-transport pipes.

Hazardous gas detection requires portable, low-power sensors with high sensitivity, where micro-heater design is critical for semiconductor metal oxide (SMO) sensors. This study presents a standardized evaluation framework for quantitatively comparing patterned micro-heaters under equal-power conditions, ensuring objective comparison across geometries. Two key metrics—power efficiency and temperature uniformity—were defined, normalized, and integrated into a single optimal score through weighted summation. The framework was validated through coupled electro-thermal simulations and experiments on six geometries, including spiral and meander patterns. Results demonstrated that the framework enables accurate identification of designs combining low power consumption with high temperature uniformity. Notably, the meander-based design showed superior efficiency and uniformity, demonstrating its suitability for practical applications. This framework thus offers a rational tool for micro-heater design, supporting the development of reliable, energy-efficient devices for portable and Internet of Things (IoT) applications.