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The increasing prevalence of the internet in our daily lives has made cybersecurity and banking security crucial concerns. Traditional methods such as passwords, fingerprints, and face recognition are becoming replicable and susceptible to hacking. To address this issue, we developed innovative biometric keystroke dynamics for personal authentication utilizing friction electric sensors. A single-electrode triboelectric nanogenerator utilizes the skin as a positive friction layer, allowing direct contact with the sensor. This arrangement enables the detection of subtle mechanical changes during pressing. To mitigate the impact of sweat and organic pollutants, a bionic rose petal friction layer is incorporated, ensuring consistent output and long-term effectiveness. The sensor efficiently converts mechanical keystroke actions into electrical signals for individuals and transmits them to an artificial neural network-based AI system. By utilizing a self-powered sweat- and dirt-proof biometric authentication system, along with the LSTM neural network algorithm, we have achieved an impressive accuracy rate of 97%. This system provides a promising security layer against password cracking and user privacy vulnerabilities. [Display omitted] • Biometric keystroke dynamic is proposed to enhance security and accuracy in verifying personal identity. • A single electrode tribo-sensor surpasses previous active sensing devices in sensitivity and flexibility. • The bionic rose petal friction layer mitigates sweat and organic contaminants, ensuring stable and long-term efficacy. [ABSTRACT FROM AUTHOR]

Wearable human-machine interfaces (HMI) have made remarkable advancements in communication, education, and healthcare, primarily driven by the rapid growth of the Internet of Things (IoT) and 5G technology. Among the various applications of wearable HMIs, there is a critical need for technologies that aid communication for blind individuals, enabling them to access information independently. However, progress in investigating blind communication has been impeded by challenges related to signal capture limitations and power supply issues. To address these challenges, this paper proposes a groundbreaking smart finger Braille typing system based on the emerging triboelectric nanogenerator (TENG). The objective of this system is to assist the blind in typing without external aid. To build an effective tactile sensing system, two essential components are required: a high-sensitivity tactile sensor and a weak current signal processing circuit. In this study, we employed electrostatic spinning to produce degradable friction nanofiber films, which significantly enhanced the sensitivity of the sensor and improved the overall device conversion efficiency. One notable advantage of utilizing TENG as a sensor is that it eliminates the need for an external power supply, ensuring self-sufficiency in the system's operation. Furthermore, we developed a specialized weak current signal processing circuit based on the unique properties of TENG, such as its high impedance and weak current characteristics. The Braille code's six dots will be represented by six self-power tactile (SPT) sensors strategically placed on both hands. By employing various tapping combinations, users can create words, which are then transmitted to mobile devices using Bluetooth technology. By introducing this innovative Braille typing system, we aim to contribute to the global mission of improving information accessibility for blind and partially sighted individuals. This system has the potential to significantly enhance their Braille literacy abilities, bridging the gap between them and the online world. [Display omitted] • A self-powered Braille typing glove is developed by TENG sensor, featuring rapid response speed and zero power consumption. • The microcontroller encodes the voltage signals generated by an array of six-channel TENG sensors to output the corresponding Braille characters. • An I/V conversion measurement significantly enhanced compatibility of the TENG sensor with the microprocessor. [ABSTRACT FROM AUTHOR]

Triboelectric nanogenerator (TENG) is a new high-efficiency electromechanical conversion mode proposed in recent years. When triboelectric nanogenerator is used as sensor, like other types of sensors, it can use current signal as sensing signal, but it outputs weak current signal with high impedance, which is not conducive to direct application. In this paper, a preprocessing method for weak current signal is proposed. The I/V conversion measurement method and the direct measurement method are theoretically analyzed, and the principle of parameter selection of circuit components is provided respectively. After that, the experiment of Contact Separated Triboelectric Nanogenerator (CS-TENG) is used to verify that the proposed I/V conversion measurement method has higher accuracy than the direct measurement method, and then the Rotary Triboelectric Nanogenerator (R-TENG) and the single electrode triboelectric nanogenerator (S-TENG) are used further verifies the design theory of the I/V conversion measurement method. Finally, it is concluded that the I/V conversion measurement method can convert the high impedance weak current signal output by TENG into a low impedance low voltage signal. Through reasonable component parameter selection, the measurement error can be controlled within 6 %, which can not only be used in current signal extraction of TENG, but also be expected to be used for current signal characterization in TENG when TENG is used as an energy harvester. An I/V conversion measurement method on the output current signal of the TENG sensor is proposed, which converts the high-impedance weak current signal output by the TENG sensor into a low-impedance and low-voltage signal, which can achieve more accurate current signal measurement. The current measurement scheme can completely restore the current change waveform output by the TENG sensor with small errors, which improves the portability and practicability of the TENG sensor. At the same time, this provides a new method for the extraction of the current signal of the TENG sensor, and can also be applied to the current signal characterization of the TENG when it used as an energy harvester. [Display omitted] • The proposed method can accurately sense the current signal of the TENG sensor with high accuracy and low cost. • The proposed method can be used as a universal approach for extracting the current signals for different kinds of TENG sensor. • The proposed method is expected to be applied to the characterization of current signal in TENG when it used as an energy harvester. [ABSTRACT FROM AUTHOR]

China has the largest number of electric bicycles (EBs) in the world; they use a considerable amount of batteries. Lead-acid batteries (LABs) are being gradually replaced with lithium-ion batteries (LIBs) in these EBs. It is necessary to explore the environmental impact of these batteries in China. This study quantified the full life cycle environmental performance of LABs (lead-antimony-cadmium, Pb–Sb–Cd, and lead-tin-calcium, Pb–Sn–Ca) and LIBs (lithium-nickel-cobalt-manganese, NCM, and lithium-iron-phosphate, LFP) through the life cycle assessment methodology. The results showed that the material extraction and processing and the battery use stages were the main processes that affected the overall environmental performance. The battery manufacturing and transportation stages had a negligible environmental impact, whereas the battery recycling could increase the environmental benefits of batteries. However, the environmental contribution of the end-of-life (EOL) stage of LIBs was not as good as LABs, especially for LFP batteries. Overall, LFP batteries had better environmental performance except for the highest carcinogenic human toxicity potentials caused by the Cr (VI) discharge from the copper production. Pb–Sn–Ca batteries had the lowest toxic potential to humans and water because of the use of cadmium-free technology. The advantages of NCM batteries over LABs were not obvious currently but had great potential for improvement. Scenarios for cycle life, recycling rate, echelon utilization, and repair and reuse of batteries were established to analyze opportunities to reduce the environmental impact of batteries. Then, several implications were proposed for the development of technology for batteries in EBs. • A comparative LCA study is conducted for electric bicycle batteries in China. • Cadmium-free is an effective green action for lead-acid batteries. • LFP batteries have environmental advantages over other batteries. • NCM batteries have no environmental advantage but big improvement potentials. • Environmental benefits of echelon utilization of LFP batteries are limited. [ABSTRACT FROM AUTHOR]

Lead is mostly found with zinc ores, but is also abundant in fossil fuels. However, the anthropogenic cycle of lead in fossil fuel system has rarely been reported. This study expounds on the evolution of lead metabolism in China's fossil fuel system from 1980 to 2018 through dynamic substance flow analysis. The quantities and structures of lead flows and stocks in the system changed significantly. After the prohibition of leaded gasoline, raw coal became the main source of lead in the system, reaching 101 kt Pb/yr in 2018. The lead outflow of the system underwent a transformation from gas phase to solid phase. The atmospheric lead emission dropped from the highest 20 kt/yr to 4 kt/yr. Most of the lead in the system accumulated in coal-based solid waste. In the past 40 years, 677 kt of lead accumulated in constructions due to the utilization of coal-based solid waste, and 657 kt of lead was left in the redundant coal-based solid waste. The main lead emission stage gradually shifted from the use stage to the waste management stage. Although the flow of lead in fossil fuels is small, there is no significant difference between unintentional (consider only fossil fuels) and intentional use of lead emissions to the atmosphere and landfills. China should improve the utilization of coal-based solid waste, and strengthen the management of landfills and dumps and the surrounding environmental monitoring. • Lead flows and stocks in China's fossil fuel system were analyzed for the first time. • Lead releases shifted from the use to the waste management of fossil fuels. • Waste utilization accumulated lead in constructions and slowed lead release. • Coal-based solid waste in landfills and dumps accumulated a large amount of lead. • Fossil fuel system and intentional use of lead release similar amounts of lead. [ABSTRACT FROM AUTHOR]

• A novel, simple and low-cost SERS substrate was synthesized for the detection of illegal food additives. • Using the novel SERS substrate, we can achieve simultaneous detection of rhodamine B and basic orange II in chili products. • This method is of great application potential for food safety detection. In food safety assessment, surface-enhanced Raman spectroscopy (SERS) is a novel detection method with the advantages of being fast, easy, and of high sensitivity. However, many SERS substrate synthesis methods are complex, and there are only a few studies on the simultaneous detection of multiple substances. In this study, a new, simple, low-cost SERS substrate was synthesised for the first time to simultaneously detect illegal food additives rhodamine B and basic orange II in chilli products. A lightweight, porous, and low-cost material of melamine foam (MF) was employed as the SERS synthesis template. The substrate's SERS effect on, and sensitivity to, rhodamine B and basic orange II were demonstrated. The molecular vibration and SERS enhancement mechanisms of the two target molecules were analysed by density functional theory (DFT) calculations. The results reveal that this fabricated substrate has great application potential for the supervision and testing industry. [ABSTRACT FROM AUTHOR]

• We conducted a LCA for five typical domestic hot water (DHW) systems in China. • Variations of climate, energy supply and energy efficiency grade are considered. • Evacuated tube solar systems are highly energy and cost-efficient for most regions. • Renewable energy systems save energy but use more materials and cause more toxicity. • China can save about 25% of energy and greenhouse gas emissions for DHW use. In this study, a cradle-to-grave life cycle assessment was conducted on several typical domestic hot water systems across five climatic regions of China. Variations of the climate and energy supply in these regions and the energy efficiency grade of domestic hot water systems were also taken into consideration. The results suggest that evacuated tube solar systems are highly energy-efficient and low-cost, except in the region with the weakest solar radiation. Electric systems are extremely energy-intensive and uneconomical for domestic hot water use, although they have the least human and ecological toxicity potentials. Solar and air-source energy systems save energy; however, they use more materials and cause more human and ecological toxicity. From the severe cold region to the hot summer and warm winter region, the heat load of domestic hot water increases by 59%, resulting in an increase of 58–230% in primary energy demand. Accordingly, the environmental impacts of domestic hot water systems increase in varying degrees; however, few impacts decrease due to the different emission factors of different power grids. The raw materials used in the manufacture of domestic hot water systems and the energy required for the use of the systems are the most important contributors to all environmental impacts. The scenario analysis indicates that 24.5% of the primary energy demand and 25.7% of greenhouse gas emissions owing to domestic hot water use in China can be reduced by improving the energy efficiency, prompting the use of renewable energy sources, and reducing the usage of materials for domestic hot water systems, as the human and ecological toxicity potentials will increase by 0.1% and 10%, respectively, due to the increasing use of certain materials. [ABSTRACT FROM AUTHOR]