A Smarter Pavlovian Dog with Optically Modulated Associative Learning in an Organic Ferroelectric Neuromem

Associative learning is a critical learning principle uniting discrete ideas and percepts to improve individuals’ adaptability. However, enabling high tunability of the association processes as in biological counterparts and thus integration of multiple signals from the environment, ideally in a single device, is challenging. Here, we fabricate an organic ferroelectric neuromem capable of monadically implementing optically modulated associative learning. This approach couples the photogating effect at the interface with ferroelectric polarization switching, enabling highly tunable optical modulation of charge carriers. Our device acts as a smarter Pavlovian dog exhibiting adjustable associative learning with the training cycles tuned from thirteen to two. In particular, we obtain a large output difference (>103), which is very similar to the all-or-nothing biological sensory/motor neuron spiking with decrementless conduction. As proof-of-concept demonstrations, photoferroelectric coupling-based applications in cryptography and logic gates are achieved in a single device, indicating compatibility with biological and digital data processing.

Control of a Rehabilitation Robotic Device Driven by Antagonistic Soft Actuators

Stroke is becoming a widely concerned social problem, and robot-assisted devices have made considerable contributions in the training and treatment of rehabilitation. Due to the compliance and continuous deformation capacity, rehabilitation devices driven by soft actuators are attached to widespread attention. Considering the large output force of pneumatic artificial muscle (PAM) and the biological musculoskeletal structure, an antagonistic PAM-driven rehabilitation robotic device is developed. To fulfill the need for control of the proposed device, a knowledge-guided data-driven modeling approach is used and an adaptive feedforward–feedback control approach is presented to ensure the motion accuracy under large deformation motion with high frequency. Finally, several simulations and experiments are carried out to evaluate the performance of the developed system, and the results show that the developed system with the proposed controller can achieve expected control performance under various operations.

Hybrid vibration energy harvesting based on piezoelectric polyline beams with electret coupling

Aiming at harvesting vibration energy more efficiently, a hybrid energy harvester is proposed, which integrates the piezoelectric and electrostatic effects. It is composed of two piezoelectric polyline beams and an electret film. The two piezoelectric polyline beams stand closely, of which one is covered by an electret film, while the other is covered by a counter-electrode. Under base excitations, the electret film interacts with the electrode, by which the two polyline beams can excite each other and form a broad frequency band of large vibration, thereby generating a large output. The dynamical equations are derived and the simulations are carried out. For validation, the experiments are conducted. The experimental results prove that the hybrid harvester is more efficient in harvesting stochastic vibration energy. For PSD = 0.0041 g2/Hz, the two piezoelectric polyline beams can generate the power outputs of 47.9 and 23.6 µW, respectively.

Design and Verification of a Charge Pump in Local Oscillator for 5G Applications

A charge pump (CP) that has low current mismatch to reduce the locking time of the Phase-Locked Loop (PLL) is proposed. The design is promising in 5G applications with the capabilities of fast settling and low power consumption. In this design, a charge pump architecture consists of an operational power amplifier (OPA), switches, three D flip-flops (DFFs) and passive devices. A phase error compensation technique is introduced in the charge pump to reduce the locking time. The current mismatch, which is mainly due to the leakage current, is below 1% for a large output voltage headroom of 84% of the supply voltage. An 18.4% reduction in the settling time is realized by the proposed design.

Anti-Corrosion Performance of Polyaniline Coated Basalt Rockwool Wastes/Epoxy Resin Coatings

Basalt rockwool wastes with large output, which are toxic and require expensive environmental treatment, are produced during the production of rock wool. Hence, it is urgent to find an effective method to reuse these materials. In this study, polyaniline (PANI)-coated basalt rockwool wastes (BRWs) were prepared as fillers to serve in coatings for the anticorrosion study. Results show that the PANI-coated BRW (PANI@BRW) had enhanced dispersion stability in several conventional solvents and improved the anticorrosion performance of the epoxy resin coating. A high protection efficiency of 97.7% could be obtained from the coating with 5% fillers after immersion for 30 days. This study not only provides a promising method of solving the issues caused by BRW, but also turns these wastes into valuable substances.

Triangulated Cylinder Origami-Based Piezoelectric/Triboelectric Hybrid Generator to Harvest Coupled Axial and Rotational Motion

Piezoelectric nanogenerators (PENGs) and triboelectric nanogenerators (TENGs) are representative technologies that can harvest mechanical energy. In general, piezoelectric/triboelectric hybrid generators can harvest considerable energy with a limited input; however, PENGs and TENGs entail different requirements for harvesting energy. Specifically, PENGs produce a large output when a large mechanical strain is applied, and TENGs require a large surface area to produce a high power. Therefore, it is necessary to develop an innovative strategy in terms of the structural design to satisfy the requirements of both PENGs and TENGs. In this study, we developed a triangulated cylinder origami-based piezoelectric/triboelectric hybrid generator (TCO-HG) with an origami structure to enable effective energy harvesting. The proposed structure consists of a vertical contact-separation TENG on the surface of the triangulated cylinder, PENG on the inner hinge, and rotational TENG on the top substrate to harvest mechanical energy from each motion. Each generator could produce a separate electrical output with a single input. The TCO-HG could charge a 22 μF commercial capacitor and power 60 LEDs when operated.

Prospects for the Improvement of Bioethanol and Biohydrogen Production from Mixed Starch-Based Agricultural Wastes

The need for fossil fuel alternatives keeps increasing. Bioethanol and biohydrogen have emerged as significant renewable options. However, these bioprocess routes have presented various challenges, which constantly impede commercialization. Most of these bottlenecks are hinged on feedstock logistics, low biofuel yield and enormous process costs. Meanwhile, a large output of renewable energy can be generated from mixed starch-based agricultural wastes due to their intrinsic bioenergy characteristics. This study, therefore, focuses on the production of bioethanol and biohydrogen from mixed starch-based agricultural wastes. The content further highlights the current challenges of their individual processes and elucidates the prospects for improvement, through an integrated biofuel approach. The use of mixed starch-based agricultural wastes as substrates for integrated bioethanol and biohydrogen production was proposed. Furthermore, the use of mixture-based experimental design for the determination of optimal values of critical factors influencing biofuel production emerges as a viable prospect for profitable bioethanol production from the starch-based biomass. Additionally, biohydrogen production from effluents of the mixed starch-based waste bioethanol looked promising. Thus, the study proposed valuable insights towards achieving a cost-effective biofuel technology.