Fabrication and Characteristics of Electret using Fine Silica Powder and Its Application of Ultrasonic Sensor

Kageyama, Kensuke; Kobayashi, Kakeru; Kawada, Yoshiaki; Sakai, Takenobu

doi:10.1541/ieejsmas.142.110

Cited by 5 publications

(21 citation statements)

References 6 publications

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“…The AE sensor was fabricated in the same way as a previously reported electret sensor used to measure AE in plants 4,7 . Configuration of ECS element and close‐up view of micro‐gap are shown in Figure 2.…”

Section: Experimental Methodsmentioning

confidence: 99%

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Detection of acoustic emission during fermentation using an electret sensor

Kageyama,

Kawarai

2023

Elect Comm in Japan

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In this study, we focused on acoustic emission (AE) as a method for quantitative evaluation of fermentation. Since bubbling in the culture medium and detachment of the medium during fermentation are considered to be phenomena similar to corrosion, AE could be expected to be detected. Therefore, we conducted AE measurements using ECS during fermentation of yeast in sucrose solution, fermentation of yeast during sake brewing, and fermentation of sawdust in a hot bath facility, and investigated the possibility of evaluation of fermentation process using electret sensor (ECS). AE was detected during the fermentation of yeast. The peak frequency of AE detected during yeast fermentation was widely distributed. Cumulative number of AE, however, showed a strong correlation with the decrease in sugar content during fermentation, indicating the possibility of quantitative evaluation of the fermentation state by AE measurement if a time lag is considered. In the measurement of AE from the fermentation of sake malt, a large amount of AE was detected from the lower part of the tank immediately after brewing, and the number of AE gradually increased in the upper part of the tank. These AE measurements suggested that even in top fermentation, the initial fermentation may occur in the lower part of the tank. In the fermentation and warm bath facility, AE during fermentation could be detected even in powdered media. Although the durability of the ECS needs to be improved under high temperature and high humidity conditions, it is expected to be able to monitor the fermentation process better than temperature measurements.

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Section: Experimental Methodsmentioning

confidence: 99%

“…The authors developed an electret‐based ultrasonic sensor (ECS: Electret Condenser Sensor) 4 . The concept of ECS is illustrated in Figure 1.…”

Section: Forewordmentioning

confidence: 99%

Detection of acoustic emission during fermentation using an electret sensor

Kageyama,

Kawarai

2023

Elect Comm in Japan

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“…The electret electrode was fabricated by the same method that was used for insulation electrode in the previous research 10 . Specifically, PTFE layer was spin‐coated on an 11‐μm thick aluminum film.…”

Section: Experimental Methodsmentioning

confidence: 99%

“…There are studies on electret applications such as non‐woven fabrics used as aerosol filters to remove fine particles from the air and energy harvesting using porous polymer electrets to convert small vibrations into electric power 6,7 . We have done research on performance improvement of an electromechanical transducer made of an electret sandwich between two electrodes and called electret capacitor sensor (ECS) 8–10 . We also developed on an ECS with electret of colloidal silica formed by spraying or silica aggregate formed by spin‐coating of fine powder; in that ECS, electret is also used as a spacer to form micro‐gaps 9,10 .…”

Section: Introductionmentioning

confidence: 99%

“…Here E g is electric field strength in gap; K v and M v are equivalent spring stiffness and equivalent mass of gap vibrating part including vibrating electrode. We explored ultrasonic characteristics in air of the ECS shown in Figure 1A to show that airborne ultrasonic waves can be transmitted and received at almost same S/N ratio in a wide frequency band over 100 kHz 10 . Normally, piezo elements made of ceramics and polymers are used in airborne ultrasonic sensors.…”

Section: Introductionmentioning

confidence: 99%

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Fabrication and characteristics of electret ultrasonic‐sensor using laser patterning

Kobayashi,

Kawada,

Kageyama

2023

Elect Comm in Japan

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In this study, in an electret capacitor sensor (ECS), which is an electromechanical exchange device consisting of an electret sandwiched between two electrodes, ridges as spacers and grooves as gaps were formed in the PTFE (polytetrafluoroethylene) layer of the insulating electrode by laser ablation. The ECSs were then fabricated using PTFE electrets, and the charge retention and airborne ultrasonic wave transmitting and receiving characteristics were investigated. The charge retention characteristics of the ECS with laser‐patterned insulating electrodes were slightly lower than those of the silica‐aggregate electret. As the thickness of the insulating layer increased or the groove width decreased, the transmitting and receiving sensitivity increased significantly and then peaked and degraded at the measurements of transmitting and receiving. The ECS with the highest peak sensitivity obtained by laser patterning had a bandwidth comparable to that of the conventional ECS with silica aggregate electret, but the peak sensitivity was improved by up to 8 dB. Therefore, laser patterning could contribute to the improvement of ECS performance.

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Study on the AE Measurement and Activity Monitoring of Living Plants in Outdoor Environment using Electret Sensors

Kageyama

2022

IEEJ Trans. SM

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Fabrication and Characteristics of Electret using Fine Silica Powder and Its Application of Ultrasonic Sensor

Cited by 5 publications

References 6 publications

Detection of acoustic emission during fermentation using an electret sensor

Detection of acoustic emission during fermentation using an electret sensor

Fabrication and characteristics of electret ultrasonic‐sensor using laser patterning

Study on the AE Measurement and Activity Monitoring of Living Plants in Outdoor Environment using Electret Sensors

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