A SelfPowered and Low Pressure Loss Gas Flowmeter Based on FluidElastic Flutter Driven Triboelectric Nanogenerator A selfpowered and low pressure loss gas flowmeter is presently proposed and developed based on a membranexe2x80x99s flutter driven triboelectric nanogenerator (TENG). Such a flowmeter, herein named xe2x80x9cTENG flowmeterxe2x80x9d, is made of a circular pipe in which two copper electrodes are symmetrically fixed and a nonconductive, thin membrane is placed in the middle plane of the pipe. When a gas flows through the pipe at a sufficiently high speed, the membrane will continuously oscillate between the two electrodes, generating a periodically fluctuating electric voltage whose frequency can be easily measured. As demonstrated experimentally, the fluctuation frequency (fF) relates linearly with the pipe flow mean velocity (Um), i.e., fF Um; therefore, the volume flow rate Q (Um A)  C1fF  C2, where C1 and C2 are experimental constants and A is the pipe crosssectional area. That is, by the TENG flowmeter, the pipe flow rate Q can be obtained by measuring the frequency fF. Notably, the TENG flowmeter has several advantages over some commercial flowmeters (e.g., vortex flowmeter), such as considerable lower pressure loss, higher sensitiveness of the measured flow rate, and selfpowering. In addition, the effects of membrane material and geometry as well as flow moisture on the flowmeter are investigated. Finally, the performance of the TENG flowmeter is demonstrated.

A Green Triboelectric NanoGenerator Composite of Degradable Cellulose, Piezoelectric Polymers of PVDFPA6, and Nanoparticles of BaTiO3 In this paper, a kind of green triboelectric nanogenerator based on natural degradable cellulose is proposed. Different kinds of regenerated cellulose composite layers are prepared by a blending doping method, and then assembled with poly(tetrafluoroethylene) (PTFE) thin films to form tribioelectric nanogenerator (TENG). The results show that the open circuit output voltage and the short circuit output current using a pure cellulose membrane is 7.925 V and 1.095 xcexbcA. After adding a certain amount of polyamide (PA6)polyvinylidene fluoride (PVDF)barium titanate (BaTiO3), the open circuit output voltage peak and the peak short circuit output current increases by 254.43% (to 20.155 V) and 548.04% (to 6.001 xcexbcA). The surface morphology, elemental composition and functional group of different cellulose layers are characterized by Scanning Electronic Microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), Xray diffraction (XRD), and tested by the electrochemical analyze. Moreover, after multiple assembly and rectification processing, the electrical output performance shows that the peak value of opencircuit output voltage and the peak value of short circuit output current increases by 132.06% and 116.13%. Within 500 s of the chargedischarge test, the single peak charge reached 3.114 V, and the two peak charges reached 3.840 V. The results demonstrate that the nanogenerator based on cellulose showed good stability and reliability, and the application and development of natural biomaterials represented by cellulose are greatly promoted in miniature electronic sensing area.