Unlimited Point Research Articles

High Durable Rotary Triboelectric Nanogenerator Enabled by Ferromagnetic Metal Particles as a Friction Material

AbstractRotary sliding mode triboelectric nanogenerator (TENG) provides high efficiency, a continuous and high output strategy for harvesting low‐frequency mechanical energy. However, poor durability owing to material abrasion during sliding restricts its practical application. Here, a novel ferromagnetic metal particle‐based triboelectric nanogenerator (FMP‐TENG) is proposed, which couples the unlimited point contact rolling motion of particles instead of planar contact of film to improve durability of TENG. Besides, due to the extensively enhanced contact area by ferromagnetic metal particles, FMP‐TENG improves its electric output, achieving a charge density of 103 µC m−2 and a peak power density of 400 mW m−2 Hz−1. After 10 000 cycle running‐in, FMP‐TENG exhibits excellent durability, which retains 97% of the output charge for 110 000 cycles. In addition, a metal powder mass sensor based on FMP‐TENG is also designed, which can effectively detect mass change in ferromagnetic metal powder in a dynamic mechanical platform. A novel strategy is proposed here to solve the problem of durability of sliding TENG in practical applications.

Low-Complexity Differential Spatial Modulation

Differential spatial modulation (DSM) is a multi-antenna technique which transmits additional data bits by selecting indexes of antennas and avoids pilot overhead. However, DSM is complicated in two aspects and we aim to reduce the complexity of DSM in this letter. First, the complexity of the noncoherent maximum-likelihood (ML) detector increases exponentially with the number of transmitter antennas. For this problem, we propose a new symbol-based ML detector whose complexity is roughly proportional to the number of transmitter antennas. The other problem is that the signal constellation of the transmitted signal has unlimited points due to complex-valued antenna-index matrices. We propose a systematic design of complex-valued antenna-index matrices for which the constellation of the transmitted signal has a few signal points only. Both the proposed techniques decrease the complexity without sacrificing error performance.

Photoacoustic pulse wave forming along the rotation axis of an ellipsoid droplet: a geometric calculation study

A geometric calculation method is developed to study the pulsed photoacoustic wave forming of an arbitrarily shaped droplet. It is found that for an ellipsoid droplet, either a prolate ellipsoid or an oblate ellipsoid, strict analytical formulas for describing the wave profile developed along the rotation axis can be derived. The results show intriguing differences compared to those of a sphere droplet in terms of the multiple geometric parameters being in effect, the pulse wave profile variant, and the existing of unlimited points of infinite tensile pressure.

Moral realism and program explanation

Alexander Miller has recently considered an ingenious extension of Frank Jackson and Philip Pettit's account of ‘program explanation’ as a way of defending non-reductive naturalist versions of moral realism against Harman's explanatory criticism. Despite the ingenuity of this extension, Miller concludes that program explanation cannot help such moral realists in their attempt to defend moral properties. Specifically, he argues that such moral program explanations are dispensable from an epistemically unlimited point of view. I show that Miller's argument for this negative claim is inadequate, and that he has, in spite of himself, identified a promising defence of moral realism.

Unlimited point algorithm for OPF problems

A nonlinear optimal power flow (OFF) algorithm is presented which allows to solve the Karush-Kuhn-Tucker (KKT) optimality conditions using a pure Newton-Raphson solution procedure. The method is similar to interior point algorithms. However, due to a simple transformation, the variable space becomes unlimited (unlimited point) and variables do not need to be forced to stay within the feasible region during all OPF iterations as is the case for interior point algorithms. As a consequence, only a pure Newton-Raphson iterative process to algebraically transformed KKT conditions is applied. The algorithm has been successfully applied to various networks up to size 700 buses with the active power loss objective function.