•New nonlinear wind input source term.•Negative wind input for adverse winds.•New wave breaking and whitecapping dissipation source term.•New swell attenuation source term.
Measurements collected ...during the AUSWEX field campaign, at Lake George (Australia), resulted in new insights into the processes of wind wave interaction and whitecapping dissipation, and consequently new parameterizations of the input and dissipation source terms. The new nonlinear wind input term developed accounts for dependence of the growth on wave steepness, airflow separation, and for negative growth rate under adverse winds. The new dissipation terms feature the inherent breaking term, a cumulative dissipation term and a term due to production of turbulence by waves, which is particularly relevant for decaying seas and for swell. The latter is consistent with the observed decay rate of ocean swell. This paper describes these source terms implemented in WAVEWATCH III ®and evaluates the performance against existing source terms in academic duration-limited tests, against buoy measurements for windsea-dominated conditions, under conditions of extreme wind forcing (Hurricane Katrina), and against altimeter data in global hindcasts. Results show agreement by means of growth curves as well as integral and spectral parameters in the simulations and hindcast.
Aluminum/graphene (Al/G) composites with enhanced heat-dissipation and mechanical properties were prepared by the powder metallurgy (P/M) technique. Graphene was first uniformly coated on the surface ...of micro-sized aluminum (Al) powders by an in-situ reduction reaction of GO and Al. Al/G bulk composites with uniform graphene dispersion in Al matrix were fabricated by the simple conventional P/M technique. Enhancements of 15.4% in thermal conductivity, 9.1% in specific heat capacity, 21.1% in hardness, and 25.6% in compressive strength were achieved with only 0.3 wt% graphene addition into pure Al.
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•Dispersion of graphene in aluminum matrix by in-situ reduction of graphene oxide on aluminum particles.•Alcohol washing was adopted to avoid the hydrolysis reaction of aluminum and guarantee the purity of the composites.•Enhancement of heat-dissipation and mechanical properties by adding graphene into aluminum matix.
Topological phases feature robust edge states that are protected against the effects of defects and disorder. These phases have largely been studied in conservatively coupled systems, in which ...non-trivial topological invariants arise in the energy or frequency bands of a system. Here we show that, in dissipatively coupled systems, non-trivial topological invariants can emerge purely in a system’s dissipation. Using a highly scalable and easily reconfigurable time-multiplexed photonic resonator network, we experimentally demonstrate one- and two-dimensional lattices that host robust topological edge states with isolated dissipation rates, measure a dissipation spectrum that possesses a non-trivial topological invariant, and demonst rate topological protection of the network’s quality factor. The topologically non-trivial dissipation of our system exposes new opportunities to engineer dissipation in both classical and quantum systems. Moreover, our experimental platform’s straightforward scaling to higher dimensions and its ability to implement inhomogeneous, non-reciprocal and long range couplings may enable future work in the study of synthetic dimensions.Topological phenomena have mostly been studied in conservative systems. Experiments on optical resonator networks now show that topologically non-trivial characteristics can also emerge in dissipation.
Plasmon polaritons are hybrid excitations of light and mobile electrons that can confine the energy of long-wavelength radiation at the nanoscale. Plasmon polaritons may enable many enigmatic quantum ...effects, including lasing
, topological protection
and dipole-forbidden absorption
. A necessary condition for realizing such phenomena is a long plasmonic lifetime, which is notoriously difficult to achieve for highly confined modes
. Plasmon polaritons in graphene-hybrids of Dirac quasiparticles and infrared photons-provide a platform for exploring light-matter interaction at the nanoscale
. However, plasmonic dissipation in graphene is substantial
and its fundamental limits remain undetermined. Here we use nanometre-scale infrared imaging to investigate propagating plasmon polaritons in high-mobility encapsulated graphene at cryogenic temperatures. In this regime, the propagation of plasmon polaritons is primarily restricted by the dielectric losses of the encapsulated layers, with a minor contribution from electron-phonon interactions. At liquid-nitrogen temperatures, the intrinsic plasmonic propagation length can exceed 10 micrometres, or 50 plasmonic wavelengths, thus setting a record for highly confined and tunable polariton modes. Our nanoscale imaging results reveal the physics of plasmonic dissipation and will be instrumental in mitigating such losses in heterostructure engineering applications.
This paper reported an experimental and numerical study of a novel brace-type hybrid damper composed of steel slit plates enhanced by the friction mechanism. A test programme including six ...proof-of-concept specimens was carried out. The test results showed that the specimens exhibited multiple yielding stages, and the hysteretic response curves of the specimens were dependent on geometric configurations of the steel slit plates and the clamping force of bolts. The expected energy dissipation sequence accompanied by excellent ductility of the novel hybrid damper specimens was confirmed. The ploughing effect phenomenon between the friction interfaces as evidenced by the wear of the steel plates and increasing friction force was confirmed, which contributed to enhanced friction energy dissipation of the dampers under cyclic loadings. Then, a numerical investigation was conducted to take insights into the resisting mechanism of the specimens. The adequacy of the finite element modelling techniques was justified by a good correlation between test responses and numerical simulations. The test and numerical studies demonstrated that the energy dissipation sequence as a result of the hybrid energy dissipation mechanism contributed to improving the energy dissipation capacity and ductility of the steel slit plates. To facilitate the practical design of the novel hybrid dampers, a theoretical prediction model enabling quantification of critical mechanical quantities of the novel hybrid damper was developed, and the sufficiency of the design model was justified by comparison among the test responses, numerical results, and design predictions.
•A novel brace-type hybrid damper composed of steel slit plates enhanced by the friction mechanism was proposed.•Six damper specimens were designed and physically tested.•Proposed hybrid damper can achieve excellent energy-dissipation capacity and ductility.•The resisting mechanism of the hybrid damper was comprehensively numerical studied.•A theoretical prediction model of the novel hybrid damper was developed.
Precessing ball solitons (PBS) in a ferromagnet during the first order phase transition is induced by a magnetic field directed along the axis of anisotropy, while the action of the periodic field ...perpendicular to the main magnetic field has been analyzed. Under these conditions, the characteristics of arising equilibrium PBS are uniquely determined by the frequency of the periodic field, but the solitons with other frequencies are impossible. For such structure, the entropy increase connected with dissipation is compensated by the decrease of the entropy due to the external periodic field. It is shown that the equilibrium PBS are essentially the "self-organizing systems" that can arise spotaneously in a metastable state of ferromagnet.
The poor interfacial stability and insufficient cycling performance caused by undesirable stress hinder the commercial application of silicon microparticles (µSi) as next‐generation anode materials ...for high‐energy‐density lithium‐ion batteries. Herein, a conceptionally novel physicochemical dual cross‐linking conductive polymeric network is designed combining high strength and high toughness by coupling the stiffness of poly(acrylic acid) and the softness of carboxyl nitrile rubber, which includes multiple H‐bonds, by introducing highly branched tannic acid as a physical cross‐linker. Such a design enables effective stress dissipation by folded molecular chains slipping and sequential cleavage of H‐bonds, thus stabilizing the electrode interface and enhancing cycle stability. As expected, the resultant electrode (µSi/PTBR) delivers an unprecedented high capacity retention of ≈97% from 2027.9 mAh g−1 at the 19th to 1968.0 mAh g−1 at the 200th cycle at 2 A g−1. Meanwhile, this unique stress dissipation strategy is also suitable for stabilizing SiOx anodes with a much lower capacity loss of ≈0.012% per cycle over 1000 cycles at 1.5 A g−1. Atomic force microscopy analysis and finite element simulations reveal the excellent stress‐distribution ability of the physicochemical dual cross‐linking conductive polymeric network. This work provides an efficient energy‐dissipation strategy toward practical high‐capacity anodes for energy‐dense batteries.
A physicochemical dual cross‐linking conductive polymeric network coupling the stiffness of poly(acrylic acid) and the softness of carboxyl nitrile rubber includes robust chemical cross‐linking and multiple physical cross‐linking. Such a design can effectively dissipate the undesirable stress of silicon microparticle anodes by folded molecular chains slipping and sequential cleavage of H‐bonds, thus stabilizing the electrode interface and enhancing cycle stability.
Efficient thermal dissipation has become a critical factor limiting the development of electronic devices. Thermal interface materials (TIMs) connecting the surfaces of heat source and heat sink, are ...important to guarantee stable and sufficient heat dissipation from heat source to heat sink. Carbon fibers (CFs) are widely used as the reinforcing fillers to enhance the thermal conductivities of polymer-based composites because of their extremely high thermal conductivities in axial direction. However, conventional methods of CFs cannot take full advantage of their high thermal conductivities because heat conductive channels in composite are not efficiently built due to the greatly larger viscosity of composite caused by CFs under high filler concentration. To solve this problem, we report a magnetic field-based and viscosity-independent method to fabricate the nickel-coated carbon fibers (NICFs) filled polydimethylsiloxane (PDMS) composites with the highspeed through-plane heat conductive channels under high filler concentration. The NICFs-composite shows 69 times enhanced through-plane thermal conductivity (10.50 W/(m∙K)) compared to that of pure PDMS (0.15 W/(m∙K)) and low thermal expansion coefficient (CTE) of 55.14 ppm/°C at 51.54 wt%. Compared to commercial TIMs, the NICFs-composites exhibits better thermal performance, demonstrating potential application prospects in electronic devices cooling area.
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