Response Characteristics of Pressure-Sensitive Conductive Elastomer Sensors Using OFC Electrode with Triangular Wave Concavo-Convex Surfaces.

The sensor response of pressure-sensitive conductive elastomers using polymeric materials can be adjusted by altering the type and quantity of fillers used during manufacturing. Another method involves modifying the surface shape of the elastomer. This study investigates the sensor response by altering the surface shape of an electrode using a readily available pressure-sensitive conductive elastomer. By employing an oxygen-free copper electrode with a flat surface (with surface roughness parameters Ra = 0.064 µm and Rz = 0.564 µm) as a baseline, we examined the sensor system's characteristics. Electrodes were fabricated with triangular wave concavo-convex surfaces, featuring tip angles of 60, 90, and 120°. Improved sensor responses were observed with electrodes having tip angles of 60 and 90°. Additionally, even with varying conductive properties of elastomers, the conductance of the elastomer sensor increased similarly when using an electrode with a 90° tip angle. This study demonstrates the potential for expanding the applications of conductive elastomer sensors, highlighting the noteworthy improvement in sensor response and performance achieved by altering the surface shape of electrodes used with commercially available conductive elastomers.

One-step formation of three-dimensional interconnected T-shaped microstructures inside composites by orthogonal bidirectional self-assembly method.

The fillers inside a polymer matrix should typically be self-assembled in both the horizontal and vertical directions to obtain 3-dimentional (3D) percolation pathways, whereby the fields of application can be expanded and the properties of organic-inorganic composite films improved. Conventional dielectrophoresis techniques can typically only drive fillers to self-assemble in only one direction. We have devised a one-step dielectrophoresis-driven approach that effectively induces fillers self-assembly along two orthogonal axes, which results in the formation of 3D interconnected T-shaped iron microstructures (3D-T CIP) inside a polymer matrix. This approach to carbonyl iron powder (CIP) embedded in a polymer matrix results in a linear structure along the thickness direction and a network structure on the top surface of the film. The fillers in the polymer were controlled to achieve orthogonal bidirectional self-assembly using an external alternating current (AC) electric field and a non-contact technique that did not lead to electrical breakdown. The process of 3D-T CIP formation was observed in real time using in situ observation methods with optical microscopy, and the quantity and quality of self-assembly were characterized using statistical and fractal analysis. The process of fillers self-assembly along the direction perpendicular to the electric field was explained by finite element analogue simulations, and the results indicated that the insulating polyethylene terephthalate (PET) film between the electrode and the CIP/prepolymer suspension was the key to the formation of the 3D-T CIP. In contrast to the traditional two-step method of fabricating sandwich-structured film, the fabricated 3D-T CIP film with 3D electrically conductive pathways can be applied as magnetic field sensor.

A one-step electric field-induced self-assembly method was developed to efficiently control the self-assembly of fillers along two orthogonal axes to form three-dimensional interconnected T-shaped microstructure assembles of carbonyl iron powder inside a polymer matrix.

ß-MoO3 Whiskers in 99Mo/99mTc Radioisotope Production and 99Mo/99mTc Extraction Using Hot Atoms.

ß-MoO3 whiskers prepared by a thermal evaporation method and α-MoO3 particles were irradiated in a nuclear reactor to produce 99Mo/99mTc radioisotopes via neutron capture. The irradiated targets were then dispersed in water to extract the 99Mo/99mTc isotopes. Of the 99Mo formed in the ß-MoO3 whiskers, 64.0 ± 7.4% was extracted with water; by contrast, only 8.8 ± 2.6% of the 99Mo formed in α-MoO3 was extracted. By comparing these data to the 98Mo concentration dissolved in water, we confirmed the hot-atom effect on both ß-MoO3 whisker and α-MoO3 particle targets to transfer 99Mo isotopes from irradiated samples to water. In addition, the ß-MoO3 whiskers exhibited a prominent hot-atom effect to transfer a higher ratio of 99Mo isotopes into water. To the best of our knowledge, this research is the first demonstration of ß-MoO3 being used as an irradiation target in the neutron capture method. On the basis of the results, ß-MoO3 is considered a promising irradiation target for producing 99Mo/99mTc by neutron capture and using water for the radioisotope extraction process in the future.

Enhancement of a pyroelectric body energy harvesting scheme employing pulsed electric fields.

This research utilizes waste heat energy as a sustainable energy source to enhance pyroelectric power output by combining pyroelectric nanogenerators with an external pulsed electric field. When the surface temperature of the pyroelectric body varies, applying different pulses of the external electric field results in maximum power accumulation. A novel power-generating experimental setup was developed to measure and compute pyroelectric power generation. A standard Fuji ceramic C-9 sample was used to generate pyroelectric energy in a 20 °C temperature range from 120 to 140 °C. The continuous temperature variation frequency was 0.05 Hz, and the pulsed electric field was applied when the temperature rose. Pulses of the electric field with widths of 10, 50, 100, and 200 ms were applied to the sample under different pulse amplitudes, and the amplitude of each pulse was 250, 500, 1000, or 1500 V/mm. The maximum power generated through the application of an external pulsed electric field under the above-mentioned conditions was evaluated. This system had the highest power density of 0.204 mJ cm-2 °C-1 kV-1. In addition, for the lowest input power, the maximum power generation condition was a 10 ms pulse width and an amplitude of 250 V mm-1 in the applied electric field. This state might power smart sensor modules, IoT devices, automobiles, and other waste heat energy applications. Nano-pulse electric field applications may reduce input power to its lowest level, dependent on net-producing power. Therefore, new researchers can use net-generation power efficiency to create a large-scale power source using multiple pyroelectric arrays.

Nanosecond pulse used to enhance the electrocoagulation of municipal wastewater treatment with low specific energy consumption.

This study compares the performance of nanosecond pulse (NSP) and direct current (DC) power supplies for use in a municipal wastewater treatment by electrocoagulation (EC). Four Al plates connected in monopolar-parallel configuration (MP-P) were used as electrodes during the EC process. The maximum chemical oxygen demand (COD) removal efficiency reached 68% and 80% using DC and NSP, respectively. Moreover, NSP treatment reduced approximately 15% of the specific energy consumption (SEC) compared with that by DC at a similar COD removal efficiency of ≈ 68%, which was used as a benchmark value. In addition, when using NSP, the SEC required to increase the COD removal efficiency from 60% to 68% was two to three times less than that when DC was applied. The results suggest that an NSP operating at 10 kHz frequency (f) and 1 µs pulse width (pw) are preferred for obtaining higher COD removal efficiencies at a low SEC. The use of an NSP for EC can enhance the COD removal efficiency and reduce the wastewater treatment SEC. The results presented herein promote the use of EC systems combined with renewable energy sources for reducing the net carbon footprint of wastewater processing.

Characterization of light absorption in thin-film silicon with periodic nanohole arrays.

Light absorption in thin-film nanostructured monocrystalline silicon (c-Si) in a glass/Ag(0.2 µm)/c-Si(1 µm) stack is characterized using simulations and measurements. Nanohole (NH) arrays designed for a practical thin-film solar cell configuration experimentally exhibit a significant improvement of the light absorption in the 1-µm ultrathin c-Si layer that exceeds the theoretical Yablonovitch limit in the long wavelength range. Fabricated square-lattice and hexagonal NH arrays give relative improvements of 65 and 70%, respectively, in the total absorption compared to a nonpatterned stack. The effect of an indium-tin-oxide (ITO) coating is also simulated, and an empty NH configuration gives the lowest ITO parasitic absorption.

Development of a simultaneous dual-ablation apparatus and preparation of compositionally gradient (Sr(1-x)Eu(x))Al2O4 thin films.

A simultaneous dual-ablation apparatus using a pulsed laser was developed for preparation of compositionally gradient thin films to explore novel compounds. Unlike other compositionally gradient thin film preparation apparatus, two targets rotated by motors were installed in and two beams splitted from a single laser were introduced to a vacuum chamber. With this apparatus, a (Sr(1-x)Eu(x))Al2O4 compositionally gradient thin film was prepared. The phase and the photoluminescence properties were investigated. The Eu optimal composition for the emission intensity in the (Sr(1-x)Eu(x))Al2O4 system was found to be x=0.06.