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The triboelectric nanogenerator (TENG) is a promising technology for self‐powered sensors and vibration‐driven energy harvesting, with its development especially influenced by the characteristics of tribomaterials. However, developing tribopositive materials with a strong cationic effect and high electron‐donating capability remains challenging. In this study, a novel polyethylene oxide@poly(diallyldimethylammonium chloride) (PEO@Poly‐DADMAC) composite nanofiber mat (NFM) is successfully fabricated using the electrospinning technique. It functions as a highly tribopositive material, particularly enhancing the performance of nanofiber‐based TENGs (NF‐TENGs). Through investigation of its physical and triboelectric properties, the study revealed that incorporating cationic Poly‐DADMAC with PEO effectively boosts NF‐TENG output by increasing the dielectric constant (twofold), electron‐donating affinities, and surface charge trapping capability. The fabricated NF‐TENG shows excellent output performance generating 980 V, a maximum power density of 5.6 Wm−2, and an ultrahigh sensitivity of 8.923 V kPa−1 which endows composite reliability for power supply and sensing capability. More importantly, the PEO@Poly‐DADMAC‐based self‐powered motion sensor with an NF‐TENG array is successfully demonstrated in multifunctional applications such as athlete activity tracking, and wireless gaming interface control. This study not only offers new insights into optimizing performance and selecting alternative tribomaterials but also provides valuable guidance for developing high‐output TENGs and highly sensitive self‐powered sensors. [ABSTRACT FROM AUTHOR]

The functionality and use of wearable triboelectric nanogenerators (TENGs) are significantly impacted by the development of their tribomaterial properties. Herein, a novel charge‐generating layer (CGL) composed of a V2CTx/Silicone nanocomposite and serpentine TENG (S‐TENG) is introduced. The V2CTx/Silicone nanocomposite exhibits a highly electronegative surface, which significantly enhances the surface potential and charge density. The fabricated nanocomposite‐based TENG exhibits a peak power density of 19.75 W m−2. It also exhibits a high mechanical stretchability (400%), which is significantly better than those of previously reported TENGs under small external pressure. The optimized S‐TENG is demonstrated as a self‐powered human motion sensor with high sensitivity (4.93 V kPa−1) and a quick rise time (21 ms). Furthermore, a real‐life demonstration of sign language interpretation using finger motion detection and text conversion via smartphones is successfully performed. Additionally, the real‐time sensing ability of the S‐TENG is demonstrated in virtual reality car games controlled by finger touch. The S‐TENG is demonstrated to capture different types of human motion energy for continuously powering a stopwatch and wristwatch. Therefore, it is expected that the V2CTx/Silicone nanocomposite will continue with the contributions of novel CGL materials for various TENG applications including wearable self‐powered sensors, robotics, and healthcare monitoring in IoT platforms. [ABSTRACT FROM AUTHOR]

The Schnakenberg model is thought to be the Caputo fractional derivative. A discretization process is first used to create caputo fractional differential equations for the Schnakenberg model. The fixed points in the model are categorized topologically. Then, we show analytically that a fractional order Schnakenberg model supports a Neimark-Sacker (NS) bifurcation and a Flip-bifurcation under certain parametric conditions. Using central manifold and bifurcation theory, we demonstrate the presence and direction of NS and Flip bifurcations. The parameter values and the initial conditions have been found to profoundly impact the dynamical behavior of the fractional order Schnakenberg model. Numerical simulations demonstrate chaotic behaviors like bifurcations, phase portraits, period 2; 4; 7; 8; 10; 16; 20 and 40 orbits, invariant closed cycles, and attractive chaotic sets in addition to validating analytical conclusions. To support the system's chaotic characteristics, we also quantitatively compute the maximal Lyapunov exponents and fractal dimensions. Finally, the chaotic trajectory of the system is stopped using the OGY approach, hybrid control method, and state feedback method. [ABSTRACT FROM AUTHOR]

Biomechanical energy harvesting shows great potential in the fields of smart electronics and biomedical Internet of Things. However, it is a significant challenge to develop a biomechanically driven energy harvester with high output power and fast charging as a sustainable power source for extended practical applications. Herein, an ultrahigh‐output triboelectric and electromagnetic hybrid generator (UHO‐TEHG) is developed to efficiently harvest biomechanical energy and provide self‐powered systems for numerous applications. The Halbach magnet array is used to concentrate additional magnetic flux in the coil and significantly enhance electromagnetic performance, while the novel poly(ethylene oxide) nanofibers enhance the triboelectric performance. Through the implementation of a mechanical spring‐mass model, and rational integration of electromagnetic and triboelectric generators, the UHO‐TEHG can provide an excellent output power of 1.02 W. Compared with existing mechanical energy harvesting devices, the fabricated device exhibits a much faster battery charging performance. Experimental results reveal remarkable performance related to biomechanical energy harvesting during walking, running, hiking, mountaineering, and self‐powered wireless human motion sensor. Real‐time charging of smartphones, smartwatches, Buds Live, and iTag via customized power management circuits is demonstrated. In addition, the fabricated UHO‐TEHG demonstrates the capability to power healthcare monitoring systems using a laser‐induced hierarchical carbon nanofiber‐based e‐tattoo sensor. [ABSTRACT FROM AUTHOR]

Self‐powered arbitrary wave monitoring is a hot research topic which aims to remove of the trouble associated with managing conventional power for continuous and real‐time acquisition of wave information from the marine environment. Herein, an effective approach is presented that simultaneously generates power from arbitrary motion waves and can sense and wirelessly transmit the wave information without requiring an external supply. The hybridized ellipsoidal device inspired from an elliptical trajectory of objects over shallow water waves, consists of six planar spiral coils arranged to cover the arbitrary direction of waves for power generation. Four magnetic force‐actuated triboelectric nanogenerators (TENGs) pairs along four sides as the arbitrary direction self‐powered wave motion sensors are integrated. Furthermore, all the required circuitry for signal processing and wireless transmission are integrally powered by the generated electricity to realize a self‐sustained wireless marine environment monitoring system. The generator can deliver peak power of 106 and 44.8 mW (at 3Hz) along with major and minor axis motion directions. The self‐powered sensors have excellent motion sensitivity thus the signals obtained from these sensors are utilized to acquire useful information related to the water waves which are very crucial parameters for real‐time monitoring of the marine environment. [ABSTRACT FROM AUTHOR]

Surface modification of triboelectric negative layers is an essential factor for boosting the output performance of triboelectric nanogenerators (TENGs). Herein, a novel scalable surface modification method is introduced using a fabric‐assisted micropatterning technique on a highly negative MXene/silicone nanocomposite surface (charge generating) with MXene layer (charge trapping) for self‐powered sensors and wearable electronics. The microstructured surface is fabricated directly from a fabric template requiring no surface‐active agent, high‐pressure equipment, or high vacuum. To boost the proposed double‐side‐contact TENG (DSC‐TENG) output performance, different parameters of the fabric textures are tested and optimized for the roughened microstructures, namely the MXene layer and relative humidity. Under optimal conditions, the fabricated DSC‐TENG improves the voltage and peak current density by factors of 9.8 and 20, respectively, regarding flat silicone. It exhibits a maximum peak power density of 55.47 W m−2 at load resistance of 0.18 MΩ, and a corresponding decrease in resistance by 75% using MXene content of 3 mg cm−2. Also, DSC‐TENG‐based smart home control of electrical appliances, theft protection, self‐powered electronic devices, password authentication, and human motion monitoring via smartphone for the IoT are demonstrated. The proposed method can be implemented for different types of polymers, thereby enabling the large‐scale fabrication of high‐performance TENGs in industrial applications. [ABSTRACT FROM AUTHOR]

Hierarchically interactive 3D‐porous soft carbon nanofibers (CNFs) have great potential for wearable bioelectronic interfaces, yet 90% of CNFs are derived from expensive polyacrylonitrile associated with complex production methods. Here, another cost‐effective fluoropolymer, poly(1,1‐difluoroethylene) (PDFE), is introduced to investigate its transition chemistry and structural evolution over laser‐induced carbonization (LIC). The impregnation of Ti3C2Tx‐MXene followed by dehydrofluorination is believed to be crucial to enhance the β‐phase and reinforce PDFE‐based nanofibers. It is explored that the β‐phase of the dehydrofluorinated MXene‐PDFE nanofibers is converted into an sp2‐hybridized hexagonal graphitic structure by cyclization/cross‐linking decomposition during LIC. Remarkably, this approach generates laser‐induced hierarchical CNFs (LIHCNFs) with a high carbon yield (54.77%), conductivity (sheet resistance = 4 Ω sq−1), and stability over 500 bending/releasing cycles (at 10% bending range). Using LIHCNFs, a skin‐compatible breathable and reusable electronic‐tattoo is engineered for monitoring long‐term biopotentials and human–machine interfaces for operating home electronics. The LIHCNFs‐tattoo with high breathability (≈14 mg cm−2 h−1) forms compliant contact with human skin, resulting in low electrode‐skin impedance (23.59 kΩ cm2) and low‐noise biopotential signals (signal‐to‐noise ratio, SNR = 41 dB). This finding offers a complementary polymer precursor and carbonization method to produce CNFs with proper structural features and designs for multifunctional biointerfaces. [ABSTRACT FROM AUTHOR]

Triboelectric nanogenerators (TENGs), which operate in contactless mode and avoid physical contact, are highly attractive for self‐powered sensor systems aiming to achieve long‐term reliable operation and reduce rubbing friction. Herein, an ultra‐flexible and high‐performance contactless double‐layer TENG (CDL‐TENG) is first designed and fabricated using a metal–organic framework‐based cobalt nanoporous carbon (Co‐NPC)/Ecoflex with MXene/Ecoflex nanocomposite layer for self‐powered sensor applications. The porous structure of the Co‐NPC provides a high‐surface‐area of the nanocomposite and the charge storage layer of the MXene/Ecoflex nanocomposite accumulates more negative charge to improve the functionality of the CDL‐TENG two and three times, respectively. Compared with Ecoflex film‐based TENGs, the fabricated CDL‐TENG exhibits an eight‐fold slower decay rate owing to charge trapping characteristics, which were confirmed by surface potential measurements. The CDL‐TENG shows excellent humidity and acceleration sensitivity of about 0.3 V/% and 2.06 Vs2 m−1. The CDL‐TENG also offers non‐contact position detection performance in the 20 cm range. Furthermore, the CDL‐TENG is successfully integrated with mobile‐vehicles and an intelligent robot to perform obstacle and human‐motion detection. Finally, a contactless door‐lock password authentication system was demonstrated. These multifunctional benefits make it useful for numerous applications, including artificial intelligence, human‐machine interfaces, and self‐powered sensors. [ABSTRACT FROM AUTHOR]

The triboelectric material properties and mechanical stability of the contact layer are vital to achieving durable triboelectric nanogenerators (TENGs) with high output performance. Herein, a novel MXene/Ecoflex nanocomposite is introduced as a promising triboelectric material because of its highly negative triboelectric properties and mechanical stability. The MXene/Ecoflex nanocomposite with a fabric‐based waterproof TENG (FW‐TENG) is fabricated and designed to universally harvest energy from various human motions as well as the natural environment (rain and wind). The fabricated FW‐TENG delivers a maximum output peak power of 3.69 mW and a power density of 9.24 W m−2, respectively, at a matching load resistance of 4.5 MΩ under a frequency of 4.5 Hz and a force of 8 N. Furthermore, the applicability of this device in various products is investigated. The FW‐TENG can protect against a crash caused by rainy and humid weather. An FW‐TENG‐based self‐powered smart active device that detects motion on a carpet is demonstrated and is equipped with sleep monitoring motion sensors. The FW‐TENG not only has self‐powered benefits and excellent mechanical amenability but is also exceptionally reliable and stable against water intrusion, which are important characteristics to realize next‐generation wearable/portable technologies. [ABSTRACT FROM AUTHOR]

Internet of Things (IoT) opens new horizons by enabling automated procedures without human interaction using IP connectivity. IoT deals with devices, called things, represented as any items from our daily life that are enhanced with computing or communication facilities. Among various mobile communications, Zigbee communication is broadly used in controlling or monitoring applications due to its low data rate and low power consumption. Securing IoT systems has been the main concern for the research community. In this paper, different security threats of Zigbee networks in the IoT platform have been addressed to predict the potential security threats of Zigbee protocol and a Security Improvement Framework (SIF) has been designed for intelligent monitoring in an office/corporate environment. Our proposed SIF can predict and protect against various potential malicious attacks in the Zigbee network and respond accordingly through a notification to the system administrator. This framework (SIF) is designed to make automated decisions immediately based on real-time data which are defined by the system administrator. Finally, the designed SIF has been implemented in an office security system as a case study for real-time monitoring. This office security system is evaluated based on the capacity of detecting potential security attacks. The evaluation results show that the proposed SIF is capable of detecting and protecting against several potential security attacks efficiently, enabling a more secure way of intelligent monitoring in the IoT platform. [ABSTRACT FROM AUTHOR]

The dynamic behavior of a discrete-time predator-prey system of Leslie type with simplified Holling type IV functional response is examined. We algebraically show that the system undergoes a bifurcation (flip or Neimark-Sacker) in the interior of R+2. Numerical simulations are presented not only to validate analytical results but also to show chaotic behaviors which include bifurcations, phase portraits, period 2, 4, 6, 8, 10, and 20 orbits, invariant closed cycle, and attracting chaotic sets. Furthermore, we compute numerically maximum Lyapunov exponents and fractal dimension to justify the chaotic behaviors of the system. Finally, a strategy of feedback control is applied to stabilize chaos existing in the system. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the dynamics of a discrete-time predator-prey system involving group defense. The existence and local stability of positive fixed point of the discrete dynamical system is analyzed algebraically. It is shown that the system undergoes a flip bifurcation and a Neimark-Sacker bifurcation in the interior of R2+ by using bifurcation theory. Numerical simulation results not only show the consistence with the theoretical analysis but also display the new and interesting dynamical behaviors, including phase portraits, period-7, 20-orbits, attracting invariant circle, cascade of period-doubling bifurcation from period-20 leading to chaos, quasi-periodic orbits, and sudden disappearance of the chaotic dynamics and attracting chaotic set. The Lyapunov exponents are numerically computed to characterize the complexity of the dynamical behaviors. [ABSTRACT FROM AUTHOR]

In this paper, we consider a classical discrete-time food chain model describing predators-prey interaction. The Holling type I functional response is used as the uptake for both predators. The existence and local stability of fixed points of the discrete dynamical system are analyzed algebraically. Using growth rate of prey as the bifurcation parameter, it is shown that the system undergoes a flip and Hopf bifurcations around planer or interior fixed point. It has been found that the dynamical behavior of the model is very sensitive to the parameter values and the initial conditions. Numerical simulations not only illustrate the key points of analytical findings but also exhibit complex dynamical behaviors of the model, such as the phase portraits, cascade of period-doubling bifurcation and determine the effects of operating parameters of the model on its dynamics. The Lyapunov exponents are numerically computed to characterize the asymptotic stability of the system dynamic response and estimate the amount of chaos in the system. [ABSTRACT FROM AUTHOR]