Breaking the barriers of electron-driven x-ray radiation in crystals
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Parametric x-ray radiation (PXR) is a prospective mechanism for producing directional, tunable, and quasi-coherent x-rays in laboratory-scale dimensions, yet it is limited by heat dissipation and self-absorption. Resolving these limits, we show the PXR source flux is suitable for medical imaging and x-ray spectroscopy. We discuss the experimental feasibility of these findings for a compact commercial PXR source.Combining with the hydraulic model experiment results of Simutasi Hydropower Station's stepped spillway,and introducing the ralative energy dissipation ration and unit-width energy dissipation power,the variation laws of step height,unit-width discharge,energy dissipation ratio,relative energy dissipation ratio, and unit-width energy dissipation power are summarized here,especially the changing regularity of relative energy dissipation ratio is studied.The results show that the relative energy dissipation ratio and unit-width energy dissipation power of stepped spillway would be increased with the increasing of flow,indicating that the energy dissipation efficacy of steps is enhanced.
Spillway
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Energy Dissipation in Solids due to Material Inelasticity, Viscous Coupling, and Algorithmic Damping
Presented is a study on energy dissipation in dynamic inelastic systems due to material inelasticity, viscous damping, and algorithmic damping. Formulation for plastic dissipation is based on thermodynamics, with consideration of plastic free energy. Computation of viscous energy dissipation of the Rayleigh type is developed and discussed. Energy dissipation due to algorithmic damping is discussed as well, and compared with the previous two, physical energy dissipation mechanisms. Energy dissipation due to all three dissipation mechanisms is illustrated and discussed in relation to single-element tests and dynamic wave propagation problems.
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In this paper, we introduce a new type of two-layer porous energy dissipation plate breakwater, consisting of one upper porous plate and a lower plate. The system is used to control energy dissipation in breakwaters. The structure performance of dissipating waves has been investigated in detail in the regular wave tests. The factors identified with the characteristics of the energy dissipation plate are discussed, such as the relative width (B/L), the relative hole-size (A/A0) and the wave steepness (H/L). The comparison and analysis of the energy dissipation coefficients with respect to different factors are presented. Model test results indicate that the two-layer porous energy dissipation system is effective in dissipating a significant amount of wave energy.
Breakwater
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Energy dissipation design is made for a frame-corewall structure. The interstory drift angles and structural dissipation ability for earthquake under seismic are analyzed by ETABS software for both the ordinary structure without friction energy dissipation bracing and two types structures with friction energy dissipation bracings.By comparison,the results show that the frame-corewall structure with friction energy dissipation bracings can control the effects which earthquake exerts on structure more efficiently,and the added structural stiffness and earthquake energy dissipation ability which the energy dissipation bracings between the frame-corewall are better than the ones between external frame.
Bracing
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Abstract In the present study we explore material architectures that lead to enhanced dissipation properties by taking advantage of squirt-flow - a local flow mechanism triggered by heterogeneities at the pore level. While squirt-flow is a known dominant source of dissipation and seismic attenuation in fluid saturated geological materials, we study its untapped potential to be incorporated in highly deformable elastic materials with embedded fluid-filled cavities for future engineering applications. An analytical investigation, that isolates the squirt-flow mechanism from other potential dissipation mechanisms and considers an idealized setting, predicts high theoretical levels of dissipation achievable by squirt-flow and establishes a set of guidelines for optimal dissipation design. Particular architectures are then investigated via numerical simulations showing that a careful design of the internal voids can lead to an increase of dissipation levels by an order of magnitude, compared with equivalent homogeneous void distributions. Therefore, we suggest squirt-flow as a promising mechanism to be incorporated in future architected materials to effectively and reversibly dissipate energy.
Void (composites)
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Two methods are proposed to derive seismic energy dissipation formulas for a new type of energy dissipation shear walls in this paper. Combined with time history analysis, the seismic energy dissipated is calculated for an energy dissipation shear wall structure model. Then, based on the dual damage criterion of foe first exceeding the maximum response and the plastic accumulative damage, the optimal analysis is done for the design parameter of the energy dissipation devices. At last, an calculating example is provided, which indicates that the stiffness and the strength of the energy dissipation devices must be moderate in other to get the optimal seismic control for this type of shear walls.
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Discussions of ‘‘real’’ and ‘‘apparent’’ dissipation of the vibrations of structural elements to which are attached substuctures, have suffered from a lack of precision in terminology. Identifying a real dissipation with the transformation of mechanical energy to heat and an apparent dissipation with the transformation of mechanical energy from a form that one observes to a form that one doesn’t, would clarify issues. A further classification of a real dissipation as either ‘‘resonant’’ or ‘‘nonresonant’’ is suggested. A resonant dissipation is obtained for vibration frequencies that are nearly coincident with the natural frequencies of a subset of the attached subsystems. Finally, a further classification of an apparent dissipation as either ‘‘reversible’’ or ‘‘irreversible’’ is also suggested. The physics underlying the different type dissipations; their modeling; and, the dependence of measures of dissipation on more fundamental measures of the attached substructures will be discussed.
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Summary The paper discusses the problem of evaluating vibration energy dissipation of a composite material. It is suggested to express the dissipation cofficient in a line (2). The reduced component dissipation coefficients c i φ i are the members of the line. The ratio of reduction c i , shows the proportion by which a separate component adds to the energy dissipation of the entire composition. By analysing the accumulated and dissipated strain energy of a composite material were obtained (6). On the basis of these expressions, formulas for calculating the dissipation coefficients of a three-layer bar and that with a galvanic covering were devised. The analysis made leads to the following conclusions: - the vibration energy dissipation coefficient of a composite material is equal to the sum of the reduced dissipation coefficients of the composition component materials; - the ratio of reduction c i depends on the value of the component accumulated energy; - for comparing separate components as to the energy dissipation, the product φ i E i should be used.
Component (thermodynamics)
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Energy dissipation ratio of stepped spillways could not reflect the energy dissipation status in detail.In order to reflect the energy dissipation function of steps,the total energy dissipation is divided into two parts: energy dissipation of traditional spillways and energy dissipation purely created by steps.The unit height energy dissipation ratio of steps and the proportion of energy dissipation created by steps are calculated.Results demonstrate that the unit height energy dissipation ratio of step is about 0.80%/m-0.83%/m,uncorrelated with unit discharge and step amount,and has a slight increase of 4.5% with the increment of step height; the proportion of energy dissipation created by steps increases with unit discharge and decreases with the increase of step amount.The decrease in energy dissipation ratio with the increase of unit discharge is because that the energy dissipation of smooth spillway reduces while the energy dissipation of stepped spillway remains unchanged.
Spillway
Energy Flow
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Abstract About 30% of the world’s primary energy consumption is in friction. The economic losses caused by friction energy dissipation and wear account for about 2%–7% of its gross domestic product (GDP) for different countries every year. The key to reducing energy consumption is to control the way of energy dissipation in the friction process. However, due to many various factors affecting friction and the lack of efficient detection methods, the energy dissipation mechanism in friction is still a challenging problem. Here, we firstly introduce the classical microscopic mechanism of friction energy dissipation, including phonon dissipation, electron dissipation, and non-contact friction energy dissipation. Then, we attempt to summarize the ultrafast friction energy dissipation and introduce the high-resolution friction energy dissipation detection system, since the origin of friction energy dissipation is essentially related to the ultrafast dynamics of excited electrons and phonons. Finally, the application of friction energy dissipation in representative high-end equipment is discussed, and the potential economic saving is predicted.
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