The Front Cover illustrates the process of closing the gap between the gas phase and the condensed phase. Aggregation effects, the influence of solvent molecules (and counter ions), and differences ...in energy dissipation cause different product distributions in the two environments. The present work describes efforts towards an understanding of the underlying principles, and the concept of pseudo‐gas‐phase conditions constitutes a valuable framework also for the transfer of reactivity. More information can be found in the Research Article by B. Butschke and co‐workers.
The use of existing large pumping station equipment for upstream residual water reverse power generation is an unrealized yet valuable renewable energy project. At present, some large axial flow pump ...stations have begun to perform reverse power generation operations; however, related research has not yet started. In this paper, entropy generation theory is applied to a large-scale axial flow pump station system in reverse power generation operations, and the entropy generation method is used to investigate the accurate size and distribution of the mechanical energy dissipation of each component under different flow conditions. First, the energy characteristics and pressure fluctuations in the pump of the large axial flow pump station system are experimentally tested under reverse power generation conditions. The reliability of the entropy generation numerical calculation is verified both experimentally and theoretically. Then, the proportion of each component in the total entropy production is compared to illustrate how each component contributes to the total entropy production of the system and how this contribution changes as operating conditions vary. Then, the type of entropy production of each component is accurately determined under different flow conditions, revealing the changes in the proportions of the different types of entropy production of each component. Finally, components with large mechanical energy dissipations are selected, and the changes and causes of the energy dissipation distribution of the components are thoroughly analysed under different flow conditions. The research results can aid in better understanding the energy dissipation mechanism of large axial flow pump systems in reverse power generation operations.
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.
We report dissipative magnon-photon coupling caused by the cavity Lenz effect, where the magnons in a magnet induce a rf current in the cavity, leading to a cavity backaction that impedes the ...magnetization dynamics. This effect is revealed in our experiment as level attraction with a coalescence of hybridized magnon-photon modes, which is distinctly different from level repulsion with mode anticrossing caused by coherent magnon-photon coupling. We develop a method to control the interpolation of coherent and dissipative magnon-photon coupling, and observe a matching condition where the two effects cancel. Our work sheds light on the so-far hidden side of magnon-photon coupling, opening a new avenue for controlling and utilizing light-matter interactions.
Using scattering amplitudes, we obtain the potential contributions to conservative binary dynamics in general relativity at fourth post-Minkowskian order O(G^{4}). As in previous lower-order ...calculations, we harness powerful tools from the modern scattering amplitudes program including generalized unitarity, the double copy, and advanced multiloop integration methods, in combination with effective field theory. The classical amplitude involves polylogarithms with up to transcendental weight two and elliptic integrals. We derive the radial action directly from the amplitude, and determine the corresponding Hamiltonian in isotropic gauge. Our results are in agreement with known overlapping terms up to sixth post-Newtonian order, and with the probe limit. We also determine the post-Minkowskian energy loss from radiation emission at O(G^{3}) via its relation to the tail effect.
•State-of-the-art review on friction type passive energy dissipation devices.•Development and application of passive dry friction damper is presented chronologically.•Limitations, challenges, and ...uncertainties associated with friction dampers are discussed.•Future research directions are highlighted.
This paper presents a state-of-the-art review on friction type passive energy dissipation devices. Friction dampers are highly preferred as an energy dissipation device, particularly for the seismic fortification of the engineering structures due to their simplicity, reliability, and maximum energy dissipation as a result of the generation of rectangular hysteretic loops. Additionally, their performance is not significantly influenced by the loading amplitude, frequency, and the number of cycles. Hence, with a better understanding of friction mechanism and behavior, numerous novel passive dry friction dampers have been invented and applied in the field of civil engineering since 1980. However, decades of studies over these dampers are highly scattered throughout the academic community. Hence, the availability of many valuable pieces of research is out of reach for further studies. Therefore, a holistic chronological detail of advancement (development and application) in the field of passive friction dampers has been presented systematically in this study. The major purpose of this paper is to present an integrated and holistic overview of passive friction damper for the ease of further studies and generate future research directions for researchers who will be working in this field.
We show that a cyclic unitary process can extract work from the thermodynamic equilibrium state of an engineered quantum dissipative process. Systems in the equilibrium states of these processes ...serve as batteries, storing energy. The dissipative process that brings the battery to the active equilibrium state is driven by an agent that couples the battery to thermal systems. The second law of thermodynamics imposes a work cost for the process; however, no work is needed to keep the battery in that charged state. We consider simple examples of these batteries and discuss situations in which the charged state has full population inversion, in which case the extractable work is maximal, and circumstances in which the efficiency of the process is maximal.
Alleviating large stress is critical for high‐energy batteries with large volume change upon cycling, yet this still presents a challenge. Here, a gradient hydrogen‐bonding binder is reported for ...high‐capacity silicon‐based anodes that are highly desirable for the next‐generation lithium‐ion batteries. The well‐defined gradient hydrogen bonds, with a successive bond energy of −2.88– −10.04 kcal mol−1, can effectively release the large stress of silicon via the sequential bonding cleavage. This can avoid recurrently abrupt structure fracture of traditional binder due to lack of gradient energy dissipation. Certainly, this regulated binder endows stable high‐areal‐capacity silicon‐based electrodes >4 mAh cm−2. Beyond proof of concept, this work demonstrates a 2 Ah silicon‐based pouch cell with an impressive capacity retention of 80.2% after 700 cycles (0.028% decay/cycle) based on this gradient hydrogen‐bonding binder, making it more promising for practical application.
A gradient H‐bonding polymer binder for Si‐based anodes is reported, where the H‐bond energies are regulated in a wide range. The well‐defined gradient hydrogen bonds can effectively release stress and maintain the integrity of the electrode via sequential bonding cleavage. Additionally, a 2 Ah pouch cell with an impressive capacity retention makes this binder more promising for practical application.
The baffle drop shaft is widely used in deep tunnel drainage systems due to its fine applicability and high energy dissipation. To fully study the turbulence characteristics and energy dissipation ...mechanism of baffle drop shafts, a 1:25 scale physical model test and a numerical simulation based on the Realizable k-ε model and Volume of Fluid (VOF) method were performed. The results showed that a baffle spacing that is too dense or too sparse is not conducive to energy dissipation and discharge. The minimum baffle spacing is the optimal structural design at the design flow rate when the flow regime is free-drop flow. The energy dissipation calculation model established in this paper has high accuracy for calculating the energy dissipation rate on the baffles in free-drop flow. The energy dissipation modes of the shaft can be divided into inlet energy dissipation, baffle energy dissipation, and shaft-bottom energy dissipation. Baffles play a major role in the energy dissipation at low flow rates, and the proportions of inlet and shaft-bottom energy dissipation increase with the increase in flow rate.
We reveal the cooperative effect of coherent and dissipative magnon-photon couplings in an open cavity magnonic system, which leads to nonreciprocity with a considerably large isolation ratio and ...flexible controllability. Furthermore, we discover unidirectional invisibility for microwave propagation, which appears at the zero-damping condition for hybrid magnon-photon modes. A simple model is developed to capture the generic physics of the interference between coherent and dissipative couplings, which accurately reproduces the observations over a broad range of parameters. This general scheme could inspire methods to achieve nonreciprocity in other systems.