Abstract High-pulsed electric field pretreatment on fruits and vegetables could enable the cell to break down and increase drying rate. It is hoped that it will help in solving practical problems in vacuum freeze-drying, such as large energy consumption, high production cost, and long drying time, etc. In order to study the influence of high-pulsed electric field pretreatment on vacuum freeze-drying of apples, the drying experiments for apples pretreated by a high-pulsed electric field were carried out. The effects of high-pulsed electric field pretreatment on drying rate, drying time, productivity per unit area, and specific energy consumption were studied separately. Based on the range analysis, the optimum parameters were obtained as follows: electric field strength 1000 V · cm−1, pulse width 120 µs, and pulse number 30 pulses. These were, in order of importance, pulse width, electric field strength, and pulse number. The comparison results showed that specific energy consumption was reduced by 20.46%, drying time was shortened by 22.50%, productivity per unit area was increased by 28.50%, and drying rate was improved by 27.02% over the results of the untreated group. Therefore, the result of complete drying of apples could be achieved by HPEF pretreatment. Keywords: AppleHigh-pulsed electric fieldPretreatmentProcess parameters optimizationVacuum freeze-drying ACKNOWLEDGMENT Funding for this research was supported by the National Natural Science Foundation of China (No. 30771242).
Liquid metal (LM) soft piezoresistive sensors, that is, devices that change resistance in response to mechanical forces, have low hysteresis and high stability, which exhibit great promise for human health monitoring. Applying stress reduces the cross-sectional area of the LM conductive path in the sensor, increasing the resistance and enabling the measurement of stress. However, increasing the sensitivity of the sensor results in a reduced measurement range and an increase in the cost. To solve this problem, this article presents a convex microarrays (CMs)-based LM soft piezoresistive stress sensor with high sensitivity and large measurement range. The CMs are located inside the microchannel, which improves the sensitivity of the sensor without reducing the measurement range. The CMs also enable the sensor to monitor bending. The mechanism of the CMs is verified by theoretical analysis, finite element simulation, and experiments. The relationship between the height of the CMs and the sensitivity is investigated. The sensor can be used in the field of human health monitoring.
In article number 2100411, Ying-Chih Lai, Michael D. Dickey and co-workers develop a naturally stretchable and elastic multifunctional liquid-metal fiber that can scavenge biomechanical energy and electromagnetic energy from surrounding electrical appliances. The multifunctional liquid-metal fiber can serve as a wearable power provider and various self-powered sensors. These findings optimally unify mechanical freedom and the capability of collecting multiple forms of ambient energy and self-powered sensing in a single fiber, opening new doors for wearable/stretchable/personal energy and sensing technologies.
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