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A method for recording the spatial distribution of radiation scattered from laser plasma in a wide angular range, up to 4π, using preexposed and developed photographic paper is proposed. This method makes it possible to obtain a radiation pattern of scattered radiation with a sufficiently high spatial and angular resolution. By calibrating the sensitivity of photographic paper, one can quantify the energy of scattered radiation in various directions and determine the integral value of the energy loss due to scattering in a wide spectral range from UV to IR. [ABSTRACT FROM AUTHOR]

Experiments of a steel sphere oblique impact with a rubber cushion have been proceeded to research the variation laws of the specific energy at interface. The contact surfaces above and under the rubber cushion can be recorded with a thin carbon paper. The parameters of deformation volume and specific energy are analyzed by the developed formulas in different cases of the impact angle, cushion thickness, drop height and sphere diameter. It is found that the deformation volume and related geometrical sizes decrease approximately exponentially with the impact angle, and the volume of the tangential moving part reaches a maximum at 50° or 60°. The variation laws of the specific energy absorption/dissipation in normal are similar to that of the axis length. The tangential specific energy can be divided into three main phases, the first two appear the states of slow increase and plateau, between of them a fluctuating peak exists at 30–40°. In final phase, the energy absorption shows sharp increase, but the energy dissipation first increases and then decreases. In addition, they increase linearly with the drop height and sphere diameter, and an optimum cushion thickness of 4 or 5 mm in the given cases. [ABSTRACT FROM AUTHOR]

• Impinging paper-thin sheets of liquids produces high energy dissipation rates. • The volume of energy dissipation is equal to the volume of the impingement zone. • A new expression for the energy dissipation rate was derived and compared with turbulence theory. • Large-eddy turnover time is approximately equal to liquid residence time in impingement zone. • Large-eddy kinetic energy decays exponentially in the impingement zone. The micromixing time of impinging thin liquid sheets depends upon the energy dissipation rate (∊). The kinetic energy released by the impingement has been previously studied and was found to be a function of the coefficient of restitution of the collision. In this work, the volume within which the released kinetic energy is dissipated was investigated. The volume of energy dissipation was determined by measuring the time required for the velocity of the liquid prior to the collision to be reduced to the velocity after the collision. High-speed video was used to measure the velocity of features, generated in the front single sheet, as they passed through the impingement zone and into the mixed sheet. The experimental results showed that the time required for the velocity change was approximately equal to the residence time of liquid in the impingement zone (t r). A new equation for ∊ was developed and compared with ∊ derived from turbulence energy-cascade theory. This comparison showed that the large-eddy turnover time (t Λ) was approximately equal to t r ; a result that is in accordance with the notion from turbulence energy-cascade theory that large, energy-containing eddies lose their energy within t Λ. Within the impingement zone, the large-eddy kinetic energy was found to decay exponentially with time. [ABSTRACT FROM AUTHOR]

This paper addresses the challenge of efficiently designing multiplexer structures in quantum-dot technology circuits. Specifically, it introduces a novel approach to constructing a 2-to-1 multiplexer through a unique gate design that relies on the interaction between cells. The key focus of this design is to minimize the utilization of cells, thereby conserving space and facilitating the creation of more complex combinational and sequential circuits. The methodology involves developing a gate structure that requires the least number of cells compared to existing designs. This reduction in cell usage not only optimizes space utilization but also enhances the scalability of the multiplexer for integration into larger circuits. The proposed gate structure demonstrates a significant improvement, achieving a 15% reduction in the number of cells compared to the previously best-known design. To further evaluate the effectiveness of this novel gate design, the study extends its analysis to include the implementation of various complex circuits such as a 4-to-1 multiplexer, D latch, and T latch. These structures are synthesized using the newly proposed gate design as a fundamental building block. To validate the functionality and performance of these circuits, simulations are conducted using the QCADesigner simulation tool. This comprehensive simulation enables a thorough assessment of the proposed structures across different circuit configurations, providing insights into their operational efficiency and suitability for practical applications in quantum-dot technology. [ABSTRACT FROM AUTHOR]

A new class of acoustic black hole (ABH) waveguides is presented, which relies in its operation on an array of optimally designed functionally graded perforated rings (FGPRs). In this manner, the developed ABH is provided with built-in energy dissipation characteristics generated by virtue of the flow through perforations, which enhances its acoustic absorption behavior and makes the speed of the propagating waves vanish faster when reaching the end of the waveguide. Furthermore, the particular design of the rings enables sandwiching of additional porous absorbing layers between the rings to further boost the absorption characteristics of the proposed ABH. Accordingly, the operating principle of the new class of ABH is radically different from that of the conventional ABH that employs sequential solid-flat rings of decreasing inner radii to create a virtual power law taper necessary for generating the black hole effect, but through reactive means rather than the effective dissipative means of the proposed ABH. Therefore, this paper develops a transfer matrix modeling (TMM) approach to model the absorption and reflection characteristics of the new class of ABH, in an attempt to predict its behavior, optimize the selection of its design parameters, and more importantly, demonstrate its merits as effective means for controlling sound propagation. Numerical examples are presented to highlight the merits and behavior of the proposed ABH. Predictions of the TMM are validated against experimental results that are available in the literature for one and two micro-perforated plates. Comparisons are also established between the ABH with FGPR and the conventional ABH in order to distinguish the behavior and underlying principles of their operations. [ABSTRACT FROM AUTHOR]

In the previous paper [C. W. Kim and I. Franco, J. Chem. Phys. 160, 214111-1–214111-13 (2024)], we developed a theory called MQME-D, which allows us to decompose the overall energy dissipation process in open quantum system dynamics into contributions by individual components of the bath when the subsystem dynamics is governed by a Markovian quantum master equation (MQME). Here, we contrast the predictions of MQME-D against the numerically exact results obtained by combining hierarchical equations of motion (HEOM) with a recently reported protocol for monitoring the statistics of the bath. Overall, MQME-D accurately captures the contributions of specific bath components to the overall dissipation while greatly reducing the computational cost compared to exact computations using HEOM. The computations show that MQME-D exhibits errors originating from its inherent Markov approximation. We demonstrate that its accuracy can be significantly increased by incorporating non-Markovianity by exploiting time scale separations (TSS) in different components of the bath. Our work demonstrates that MQME-D combined with TSS can be reliably used to understand how energy is dissipated in realistic open quantum system dynamics. [ABSTRACT FROM AUTHOR]

Many proposals are being made for cleaner, more sustainable forms of energy production. Terrestrial solar photovoltaic farms (SPFs) could potentially deliver large quantities of energy to the grid, although these are limited to daytime use. The output from these SPFs could be enhanced, particularly around dawn and dusk, by the use of orbiting solar reflectors (OSRs) in near-polar orbit. These would reflect an image of the solar disk, or solar image (SI), onto the SPFs to augment their energy output. Pointing requirements are therefore to ensure that reflected sunlight is delivered to the terrestrial SPF, avoiding the losses incurred by an offset of the SI and the SPF itself. The SI would typically be of order 10 km for a reflector in a 1000 km orbit. Given the potentially large size of the reflectors, this presents a challenge for the attitude determination and control system (ADCS) to ensure that the maximum quantity of energy can be delivered to a SPF, typically requiring large control moment gyro actuators. In addition, there exist numerous sources of error in the ADCS which can cause further degradation in the quantity of energy delivered to the SPF. These errors can manifest in the resolution of the various sensors, flexible structural modes, manufacturing inaccuracies, and misalignments due to vibration during launch. This paper will investigate the effects of pointing error sources (PES) on the reflector ADCS and so on the quantity of energy delivered to the SPF. With the application of a PD controller with feedforward compensation, and the set of noise characteristics defined in this paper, numerical simulations will show the typical losses in energy delivered to SPFs of 0.015% when the model accounts for PES in onboard sensors, actuator uncertainty and flexible structural modes. • Orbiting solar reflectors. • Sensor and actuator noise modelling. • Establishing the energy delivery losses due to noise in OSRs and finding the minimum losses using PD controllers. [ABSTRACT FROM AUTHOR]

This paper examines the use of Phase Change Materials (PCM) in Building-Integrated Photovoltaic (BIPV) systems. To assess the performance of BIPV–PCM systems, the study employs a Strengths, Weaknesses, Opportunities and Threats (SWOT) analysis. The study features the advantages of using PCMs with BIPV envelopes. The benefits include lower heating and cooling requirements, shifted peak loads and increased thermal comfort. However, there are several challenges like heat loss and lower energy efficiency which needs to be addressed. Further, the potential for reduced PCM efficiency over time is recognized. The paper concludes by recommending further research on alternative PCM placement strategies, enhanced PCM formulations, gypsum board integration and the evaluation of PCMs combined with nanoparticles. [ABSTRACT FROM AUTHOR]

This paper reviews sintered silver (s-Ag) die-attach materials for wide band gap (WBG) semiconductor packaging. WBG devices that die-attach with s-Ag have attracted a lot of attention owing to their low energy loss and high temperature operation capabilities. For their practical operation, a reliability design should be established based on the failure of physics of the s-Ag die layer. This paper first focuses on the material characteristics of the s-Ag and tensile mechanical properties. Then, the s-Ag die-attach reliability is assessed with high-temperature storage, power cycling, and thermal shock tests. Each fracture mode was discussed by considering both the fracture surface analysis results and its mechanical properties. Finally, the effective reliability design parameters of the s-Ag die layer are introduced. [ABSTRACT FROM AUTHOR]

Energy saving is an important measure to promote social green transformation. The traditional energy-saving ideas usually only focus on a specific loss, and seldom consider the possible relationship and influence among various losses. In relatively complex energy-using systems, there are often many kinds of losses, and each loss may have many influencing factors. There may be some relationship between these losses and the influencing factors. To solve this problem, this paper presents an analysis method of the variable association in multi-variable systems. First, the basic relationships between variables and the representation methods are discussed. The basic concept of a path between variables is given, and the analysis method of variable association based on path statistics is provided. This paper focuses on the analysis of the influencing factors and paths of the observed variables, as well as which observed variables will be affected by a control variable. Then, based on the correlation matrix, the quantitative analysis method of the influence between variables is given. Variable correlation analysis is innovatively applied in the field of energy saving to determine the correlation of losses through variable associations, guiding the preliminary screening of energy-saving measures and analyzing the collateral effects of these measures. Based on the correlations between energy losses, a scientific process for formulating energy-saving measures is proposed. The variable correlation analysis method proposed in this paper is a generalized method, which can judge the correlation between variables from the perspective of theoretical analysis and avoid the dependence on data. In addition to good applications in the field of energy conservation, it can also be widely used in construction, transportation, climate change, and other fields. The proposed energy-saving ideas take into account the intensity of influencing factors on loss and the correlation between loss, which improves the effectiveness of energy saving measures. [ABSTRACT FROM AUTHOR]

Practical adhesion of pressure-sensitive adhesives (PSAs) is strongly dependent on their viscoelastic properties. The use of biobased materials emerged as an effective approach to modify the rheological, mechanical, and adhesive properties of PSAs. The biopolymer kraft lignin (KL), a by-product of pulp and paper manufacturing, appeared as a potential candidate for modifying the adhesive behavior of PSAs. In this study, we developed a block copolymer-based PSA by incorporating a hydrocarbon resin (HCR) and kraft lignin into the block copolymer polystyreneb-poly(ethylene-co-butylene)-b-polystyrene (SEBS). "Viscoelastic windows", which describe the potential application of a PSA based on its viscoelastic behavior, were constructed for PSAs with the addition of KL. These results demonstrate the potential for application as a high-shear PSA due to the increased energy dissipation of the samples. Practical adhesion was evaluated using probe tack tests and lap shear strength measurements, which effectively demonstrated an increase in the cohesive strength of the PSA with an optimized concentration of 5 wt% KL. [ABSTRACT FROM AUTHOR]

This research paper introduces an optimization methodology for the strategic electric sources' placement at multiple positions in a DC islanded microgrid characterized by a mesh network, aiming to minimize line losses while considering minimal cable weight. The DC microgrid studied in this paper is composed of PV panels, batteries, a diesel generator, and 20 residential loads. Employing Dijkstra's algorithm, a graph algorithm used in Google Maps, the study identifies the shortest path (resistance) between potential source nodes and various variable loads within a predefined electric distribution mesh network topology. This study focuses on active power considerations and offers valuable insights into the placement optimization of multiple sources' positions in DC microgrid mesh networks. A key contribution of this paper lies in the ranking of source node positions based on minimal to maximal line losses, taking into consideration optimal cable weights, while using MATPOWER to validate sources' ranking based on Dijkstra's hypothesis. The research further includes a techno-economic study to assess the viability of sources' placement at multiple positions within the mesh network, comparing it with the optimal placement scenario involving a single position for all sources. This methodology serves as a valuable resource for system designers and operators aiming to minimize line losses and optimize energy distribution in DC microgrids in a mesh topology. [ABSTRACT FROM AUTHOR]

In response to the problem that the standard AT2 phase field model cannot effectively model quasi-brittle failure and the existence of length dependence, a new modified phase field model is presented in this paper. By introducing an additional energy, the competing relationship between elastic strain energy and dissipation energy during fracture is changed. A new crack dissipation functional is established using the energy equivalent approach. By introducing a novel rational degradation function, not only can the strength of material failure be effectively utilized, but the model can also reproduce the cohesive softening relationship. A multi-field finite element method is used to discretize the model governing equations, and the equations are solved by an efficient BFGS monolithic algorithm. Finally, some representative numerical examples are used to analyze the effects of parameters in degradation function, length scale and mesh size on the results. The presented numerical simulation results demonstrate length scale and mesh scale independence, and are in good agreement with the experimental results and previous numerical results. At the same time, the numerical results also exhibit cohesive softening properties similar to the current phase field cohesive zone model. These results verify the robustness and effectiveness of the modified phase field model presented in this paper for simulating quasi-brittle failure and brittle fracture. [ABSTRACT FROM AUTHOR]

Due to its simplicity, the one-diode model is commonly used for modeling the operation of photovoltaic (PV) modules at standard test conditions (STC). However, its inherent implicit nature often presents challenges in modeling PV energy production. In this paper, the innovative explicit one-diode model developed by us over time is adapted for estimating PV power production under real weather conditions. Simple yet accurate equations for calculating the energy output of a PV generator equipped with a maximum power point tracking (MPPT) system are proposed. The model's performance is assessed under various normal and harsh operating conditions against measured data collected from the experimental setup located at the Solar Platform at West University of Timisoara, Romania. As an application of the new equation for maximum power, this paper presents a case study where the energy loss in the absence of an MPPT system is evaluated based on atmospheric and sky conditions. [ABSTRACT FROM AUTHOR]

The dynamic response of dielectric elastomers is widely used in many functional devices, but current research has neglected the effect of varying dielectric permittivity on their dynamic oscillations and stability. This paper studies the thin-walled dielectric balloon in which the stretch-dependent dielectric permittivity is considered. We obtain the dynamic equation of motion by Hamilton's principle. Based on the principle of no energy dissipation in conservative systems, we establish energy conservation at the maximum stretching position and at the initial moment, then we investigate the stability in the dynamic case. It is found that a stretch-related dielectric permittivity can increase the critical electric field of the balloon and can also change the mode of electric field instability and modulate the critical stretch value. In the dynamic case, the stretch-dependent permittivity increases the critical electric field by 4 % when the balloon is only subjected to electric force; moreover, it increases the critical stretch value by 316.68 % by changing the unstable mode from pull-in instability to snap-through instability. It is hoped that this work will provide new thinking in designing functional devices by using the dynamical response and stability of dielectric elastomers. [ABSTRACT FROM AUTHOR]

Given that thermoelastic damping (TED) is one of the main causes of energy dissipation in miniaturized structures, calculation of its exact amount is of particular importance in the design of such elements. Considering three-dimensional (3D) heat transfer along with the scale effect on both mechanical and thermal areas is one of the decisive factors in the more rigorous modeling of TED in small-sized resonators. This paper exploits the modified couple stress theory (MCST) and dual-phase-lag (DPL) heat conduction model to establish an analytical TED relation for rectangular micro/nanoplate resonators with 3D heat conduction. At the start, the non-Fourier heat equation corresponding to 3D DPL model is derived. Then, the solution of temperature distribution is determined by employing infinite trigonometric series. Moreover, the scale-dependent frequency of the system is presented in the context of MCST. Eventually, with the help of entropy generation (EG) method, an analytical TED expression considering 3D heat conduction is established. The precision of the presented solution is examined by comparing it with a simpler model available in the literature. By choosing two common types of boundary conditions, i.e. fully-clamped (CCCC) and fully-simply (SSSS) supported plates, the influence of various factors on TED changes is comprehensively investigated in simulation section. According to the outcomes, in plates with a lower ratio of length and width to thickness, the dimension considered for heat conduction model has a noticeable impact on the variations of TED. [ABSTRACT FROM AUTHOR]

In this paper, we derive the dissipation term in the local energy balance law of weak solutions for a surface growth model arising in the molecular-beam-epitaxy process by using the third-order structure functions. This enables us to address Yang's question posed in [52, J. Differential Equations 283, 2021] , consider generalized Onsager conjecture, and present an upper bound of energy dissipation rate of the form O (ν 3 α − 1 α + 1 ) under the condition that the weak solution h ν belongs to L 3 (0 , T ; B 3 , ∞ α + 1 (T)) with α ∈ (0 , 1) in this model. More importantly, the link between Duchon-Robert's remarkable dissipation term and Lions's classical sufficient condition for energy balance law in the 3D Navier-Stokes equations is illustrated. [ABSTRACT FROM AUTHOR]

The internal damping has a significant influence on the dynamic performance of carbon fiber-reinforced plastic (CFRP) drive shaft. In this paper, the traditional damping strain energy model of composite structures was modified using the reverse off-axis transformation. The damping ratio of CFRP hollow tube pieces is then tested using the vibration method, and the accuracy and efficiency of the modified damping numerical model are verified. Meanwhile, the modified model was proposed to study the damping characteristics and contribution rate of the CFRP hollow tube. The results show the influence law of the laminate parameters on the bending and torsion damping of the CFRP hollow tube. How the strain energy dissipation affects the damping of the CFRP hollow tube is discussed, and the mechanism relationship between the laminate parameters and damping is explored. This study provides theoretical guidance for the design of the bending and torsion damping of CFRP hollow tube. [ABSTRACT FROM AUTHOR]

This paper presents a dynamic positioning control scheme for offshore drilling platforms using the equivalent-input-disturbance (EID) method with separated observers. The scheme incorporates observer-based disturbance compensation, wave-filtering state estimation, input transformation, and state feedback control to achieve robust control performance. The main contributions include the design of an EID scheme with separated observers, enabling enhanced disturbance-rejection performance, incorporating a notch filter in the EID estimator to reduce energy loss, and giving an observer tuning scheme to achieve a balanced performance between disturbance rejection and wave filtering. Simulation results demonstrate the effectiveness of the proposed scheme. This work provides valuable insights into designing stable and efficient dynamic positioning systems for offshore drilling platforms. [ABSTRACT FROM AUTHOR]

In this paper, an extension of the Timoshenko model for plane beams is outlined, with the aim of describing, under the assumption of small displacements and strains, a class of dissipative mechanisms observed in cementitious materials. In the spirit of micromorphic continua, the modified beam model includes a novel kinematic descriptor, conceived as an average sliding relevant to a density of micro-cracks not varying along time. For the pairs of rough surfaces, in which such a distribution of micro-cracks is articulated, both an elastic deformation and a frictional dissipation are considered, similarly to what occurs for the fingers of the joints having a tooth saw profile. The system of governing differential equations, of the second order, is provided by a variational approach, endowed by standard boundary conditions. To this purpose, a generalized version of the principle of virtual work is used, in the spirit of Hamilton–Rayleigh approach, including as contributions: (i) the variation of the inner elastic energy, generated by the linear elasticity of the sound material and, in a nonlinear way, by the mutual, reversible deformation of the asperities inside the micro-cracks; (ii) the virtual work of the external actions consistent with the beam model, i.e., the distributed transversal forces and the moments per unit lengths; besides these two contributions, constituting the conservative part of the system, (iii) the dissipation due to friction specified through a smooth Rayleigh potential, entering a nonlinear dependence of viscous and Coulomb type on the sliding rate. Through a COMSOL Multiphysics implementation, 1D finite element analyses are carried out to simulate structural elements subjected to three- and four-point bending tests with alternating loading cycles. The dissipation of energy is investigated at varying the model parameters, and the predictions turn out to be in agreement with preliminary data from an experimental campaign. The present approach is expected to provide a valuable tool for the quantitative and comparative assessment of the hysteresis cycles, favoring the robust design of cementitious materials. [ABSTRACT FROM AUTHOR]

The paper deals with a new model based on Eringen's nonlocal thermoelasticity. The propagation of Rayleigh waves in a nonlocal thermoelastic layer which is lying over a nonlocal thermoelastic half-space is considered in the context of energy dissipation theory. The normal mode analysis is employed to the considered equations to obtain vector matrix differential equation which is then solved by state space approach.The frequency equation of Rayleigh surface wave is derived. The effect of the nonlocal parameter on phase velocity, attenuation coefficient, specific loss and penetration depth of Rayleigh surface waves is presented graphically. [ABSTRACT FROM AUTHOR]

This paper proposes a local discontinuous Galerkin (LDG) method for the stochastic Korteweg-de Vries (KdV) equation with multi-dimensional multiplicative noise. In the mean square sense, we show that the numerical method is L 2 stable and it preserves energy conservation and energy dissipation. If the degree of the polynomial is n , the optimal error estimate in the mean square sense can reach as n + 1. Finally, structure-preserving and convergence are verified by numerical experiments. [ABSTRACT FROM AUTHOR]

Energy losses and purity of product gases in alkaline water electrolysis strongly depend on properties of a separator positioned between the electrodes. This paper reports on heterogeneous separators based on microporous polysulfone membranes modified by graft co-polymerization of acrylic acid. After neutralization with KOH, the pores of the modified membranes were filled with potassium polyacrylate, a superabsorbent material forming hydrogel upon intake of an aqueous electrolyte. Under electrolysis conditions of 50 °C and atmospheric pressure, increasing amount of hydrogel in pores suppresses hydrogen permeability without apparent reduction of ionic conductivity. We have identified the product of ionic resistance and hydrogen flux as a suitable parameter to compare performance of separators of various thickness. In terms of this parameter, present separators surpass the performance of Zirfon™ Perl UTP 500 tested under the identical conditions. Ex-situ aging test in 30 wt% KOH at 60 °C has revealed preservation of high wettability for up to 1340 h. [Display omitted] • Graft co-polymerization of acrylic acid is achieved on microporous polysulfone membranes. • Modified membranes exhibit high ionic conductivity and low hydrogen permeability under electrolysis conditions at 50 °C. • High wettability is retained in KOH electrolyte at 60 °C for 1340 h. [ABSTRACT FROM AUTHOR]

Seismic isolation technologies for large‐span structures have rapidly developed alongside the popularization of the seismic resilience concept. To produce a high‐efficiency isolation technology with lower energy dissipation demands, this paper proposes a novel inerter‐enabled isolator (IeI) and a tailored input energy reduction‐oriented design method. The inerter‐based damper within the IeI is developed by combining the dashpot, tuning spring, and two inerters to facilitate the optimization of inerter distribution. Assuming the large‐span structure remains linear, the overall seismic input energy of the large‐span structure with IeIs and its allocation in the superstructure and additional damping are quantified using stochastic energy analysis. The advantages of the IeI over the conventional linear viscous damper (LVD) isolator are elucidated through dimensionless parametric analysis. Based on the results of parametric analysis, an input energy reduction‐oriented design method is proposed for the IeI, along with an easy‐to‐follow diagram that helps with preliminary design in practical applications. The effectiveness of the IeI and the proposed design method is validated through a design case study of a benchmark large‐span structure. The results demonstrate that the IeI reduces the seismic response of large‐span structures by simultaneously employing the input energy reduction effect of grounded inerters with the damping‐enhancing effect of inerter‐based dampers. The proposed design method effectively balances the performance of controlling the large‐span structure and the isolator displacement. Under consistent control performance and isolator displacement constraints, the IeI requires much less damping coefficient and energy dissipation capacity than the conventional LVD isolator. Moreover, leveraging the damping enhancement and input energy reduction effects, the IeI achieves comparable control performance to the conventional LVD isolator, even under stricter isolator displacement constraints. [ABSTRACT FROM AUTHOR]

Due to the continuously increasing power density of electronic devices, the improvement of the temperature uniformity and the reduction of the irreversible energy losses became crucial in these studies on enhanced cooling capacity of the heat sinks. In this paper, a jet impingement microchannel heat sink with airfoil fins (AF‐JIMHS) is proposed. The AF‐JIMHS with reversed fins arrangement has very high comprehensive heat transfer performance. The increase of the internal tangent circle radius and chord length of fin can improve the temperature uniformity of the AF‐JIMHS bottom surface and reduce the irreversible energy losses, at the expense of reducing its comprehensive heat transfer performance. Although the increase of the tangent arc length of fin reduces the temperature uniformity and increases the irreversible energy losses of the AF‐JIMHS, it improves the comprehensive heat transfer performance in a specific parameter range. The increase of fin height improves temperature uniformity of the AF‐JIMHS, while reducing its irreversible energy losses and improving its comprehensive heat transfer performance. Compared with the AF‐JIMHS with uniform height fins, the one with decreasing height fins has higher comprehensive heat transfer performance and lower irreversible energy losses. Moreover, the AF‐JIMHS with increasing height fins has better temperature uniformity. [ABSTRACT FROM AUTHOR]

Electric vehicle (EV) fast charging stations (FCSs) are essential for achieving net-zero carbon emissions. However, their high power demands pose technical hurdles for medium-voltage (MV) distribution networks, resulting in energy losses, equipment performance issues, overheating, and unexpected tripping. Integrating FCSs into the grid requires considering annual and seasonal variations in EV fast-charging energy consumption. Neglecting these variations can lead to either underestimating or overestimating the impacts of FCSs on the networks. This paper introduces a probabilistic method to assess voltage profile violations, overload capacity, and increased power losses due to FCSs. By incorporating annual and seasonal time-series data, the method accounts for uncertainties related to EV fast charging. Applied to an MV feeder in Brazil, our evaluations highlight the impact of annual power consumption seasonality on EV-grid integration studies. Considering seasonal dependency is crucial for precise impact assessments of MV distribution networks. The proposed method aids utility engineers and planners in quantifying and mitigating the effects of EV fast charging, contributing to more reliable MV grid integration strategies. [ABSTRACT FROM AUTHOR]

This paper conducts an in-depth study of a wireless, hierarchical structure-based active balancing system for power batteries, aimed at addressing the rapid advancements in battery technology within the electric vehicle industry. The system is designed to enhance energy density and the reliability of the battery system, developing a balancing system capable of managing cells with significant disparities in characteristics, which is crucial for extending the lifespan of lithium-ion battery packs. The proposed system integrates wireless self-networking technology into the battery management system and adopts a more efficient active balancing approach, replacing traditional passive energy-consuming methods. In its design, inter-group balancing at the upper layer is achieved through a soft-switching LLC resonant converter, while intra-group balancing among individual cells at the lower layer is managed by an active balancing control IC and a bidirectional buck–boost converter. This configuration not only ensures precise control but also significantly enhances the speed and efficiency of balancing, effectively addressing the heat issues caused by energy dissipation. Key technologies involved include lithium-ion batteries, battery management systems, battery balancing systems, LLC resonant converters, and wireless self-networking technology. Tests have shown that this system not only reduces energy consumption but also significantly improves energy transfer efficiency and the overall balance of the battery pack, thereby extending battery life and optimizing vehicle performance, ensuring a safer and more reliable operation of electric vehicle battery systems. [ABSTRACT FROM AUTHOR]

C4F7N is considered the most promising alternative to SF6 due to its higher liquefaction temperature, and it is generally mixed with buffering gases such as CO2 in engineering applications. This paper establishes a two-dimensional axisymmetric nozzle arc model based on magnetohydrodynamics, calculating the nozzle arc for air, SF6, and C4F7N/CO2 mixtures. The simulation model's accuracy is validated by comparing the calculation results for air with experimental data. This study focuses on comparing and analysing the temperature distribution, arc voltage, and energy balance characteristics of the nozzle arcs for SF6 and C4F7N/CO2 mixtures. By comparing the physical properties of the two gases, the differences in their arc characteristics are explained. Finally, the influence of different C4F7N concentrations on the arc characteristics of the mixed gas is compared. The results show that the arc voltage of the C4F7N/CO2 mixtures is higher than that of the other two gases and increases asymptotically with the decrease in current. Among the three gases, the main form of arc energy dissipation is axial thermal convection, and both radial heat transfer and axial thermal convection are more significant in the C4F7N/CO2 mixtures, resulting in the lowest arc temperature, which is more conducive to arc extinguishing. This study provides an in-depth explanation of the differences in arc morphology and temperature between SF6 and C4F7N mixed gases by comparing their ρ C p and ρ h . The findings offer theoretical support for the design and optimisation of new environmentally friendly circuit breakers. [ABSTRACT FROM AUTHOR]

Friction dampers are widely used due to their simple structure, remarkable energy dissipation capacity, and frequency independence. However, existing friction dampers are prone to relaxing the preload force during long‐term service, which can lead to cold bonding or cold solidification. To overcome this critical shortcoming, a novel non‐preload variable friction damper (NVFD) was firstly proposed. The construction of the proposed NVFD is provided in detail. Furthermore, restoring the force model through the amplification factors of friction force and inertial mass was derived based on the principle of the proposed NVFD. Then, pseudo‐static tests with various parameters were conducted. Finally, a single‐degree‐of‐freedom (SDOF) structure was employed to compare the effectiveness of this paper's new NVFD with a conventional friction damper (FD) under various earthquake levels. The results show that non‐preload characteristics avoided the problems of large preloads by traditional friction dampers; thus, the NVFD had stable and reliable variable friction performance, which can effectively adapt to different hazard levels. [ABSTRACT FROM AUTHOR]

Data‐driven structural health monitoring (SHM) is an approach which relies on the information contained in the data and through signal analysis techniques captures the features, variations, and uncertainties that data contain. This paper presents the response of shaking table tests of a full‐scale, 3‐story building with sliding slabs connected by horizontal buckling‐restrained braces for energy dissipation. First, the global dynamic characteristics of the structure were identified from a series of the building response data under different intensity level of base excitations. The variation of the identified modal parameters, such as the mode frequencies and modal shapes, was discovered. The influence of sliding slabs on the dynamic characteristics of the frame was also investigated through the measured response and the equation of motion with six degree of freedom systems. Comparison on the achieved interstory stiffness due to the implementation of sliding slabs and the fixed (locked up) slab was examined. The mechanism and dynamic characteristics of sliding slabs, including energy dissipation of the friction force, BRB hysteresis behavior, and unintended damping force during strong base excitation were analyzed directly using the ARX/recursive model. The extracted unintended damping force performed like a friction hysteretic response, which needs to be considered for frame modeling in shaking table tests. The findings through the data analysis have clarified the important aspects of sliding slabs and demonstrated the benefits and applicability of sliding slabs on reducing the frame response. [ABSTRACT FROM AUTHOR]

In this paper, a heat generator with fluid agitation is developed and experimentally studied. This heat generator can convert kinetic energy from a wind turbine directly to thermal energy through the process of viscous dissipation—a process achieved through the agitation of the working fluid inside a container. In the experimental study, an electric motor (instead of a wind turbine) was used to provide the kinetic energy input to the heat generator. The torque, rotational speed, and temperature rise in the fluid were measured. Using the measured quantities, the efficiency of kinetic energy to sensible heat conversion was calculated. Experiments were conducted to investigate the effects of different impellers, rotational speeds, and working fluids, including distilled water, ethylene glycol (EG), and their respective nanofluids, with A l 2 O 3 nanoparticles at different concentrations. The study also found that the temperature rise in fluids due to viscous dissipation was influenced by the specific heat of the fluid, suggesting that the heat generator can be optimized for energy storage with high-specific-heat fluids, such as water, or for achieving a higher temperature rise with low-specific-heat fluids, such as ethylene glycol. The experimental results indicated that the heat generator was up to 90% efficient in converting kinetic energy to thermal energy. The study revealed that, for constant power input, the heat dissipation rate depends solely on the vessel's geometry, not the fluid properties. Optimizing the impeller design and baffles within the vessel is crucial for maximizing power input. For applications, a wind turbine can power this heat generator to provide heat to a house or a commercial building. [ABSTRACT FROM AUTHOR]

Providing any accurate fracture criteria for composite materials requires consideration of energy dissipation effects at the crack tip due to its quasi-brittle nature. In this paper, a non-local damage model is incorporated into the reinforced isotropic solid (RIS) model for mixed mode I/II fracture assessment of orthotropic materials. In contrast with the local stress, in the non-local stress approach the effects of the fracture process zone (FPZ) can be included into the criterion with defined coefficients. After choosing an appropriate criterion to investigate the growth of micro-cracks, the concept of non-local stress (NLS) is used for developing the mentioned criterion. Due to the formation of the fracture process zone in the matrix of the damaged material, the RIS concept is used as a superior material model to simulate the fracture behavior of orthotropic materials. In RIS model, fibers take part as matrix reinforcements, and their effects are considered as stress reduction coefficients in theoretical investigation. Initial cracks are considered along and perpendicular to the fibers. The concept of crack kinking and growth along the fibers is utilized to develop fracture criterion for cracks perpendicular to the fibers. In comparison with available criteria, this criterion can consider different crack–fiber angles. Combination of the RIS theory with this defined damage coefficient presents a new model for prediction of the properties of damage zone for the cracked orthotropic materials. Fracture envelop curves in comparison with the available experimental results show the capability of the presented criterion in predicting the moment of failure of orthotropic materials. [ABSTRACT FROM AUTHOR]

With the increasing complexity of digital systems, managing power dissipation and energy consumption in digital circuits, particularly in emerging embedded systems for artificial intelligence and signal processing applications, has become a challenging issue. The emerging paradigm of approximate computing offers the potential to reduce energy consumption and enhance speed by trading accuracy. This paper introduces several 4-bit approximate multipliers and outlines a systematic approach for constructing extended bit-length multipliers by leveraging lower bit-length counterparts. Our evaluations confirm that, in comparison with state-of-the-art approximate multipliers, the proposed multipliers demonstrate energy reduction of up to 50, 76, and 83% in 8-bit, 16-bit, and 32-bit multipliers, respectively. Additionally, the reduction in energy-delay product (EDP) reaches up to 86, 93, and 97%, correspondingly. The efficiency of the proposed approximate multipliers has been explored and confirmed in executing various image processing algorithms, a regression model developed for stock price prediction, and in executing quadrature amplitude demodulation. [ABSTRACT FROM AUTHOR]

Dynamic imbalance is one of the primary issues in rotary compressor applications, which can generate significant vibration. A dynamic balance design is required to minimize the moment and additional inertia force, which can be eliminated by adding a counterweight. This paper utilized a solid plate that has cavities filled with particle damper as a novel design to satisfy the dynamic balance. Vibrational energy is dissipated in collisions between particles through momentum exchange and is converted into energy for consumption that consists of inelastic collision energy and frictional energy. The discrete element method (DEM) and multi-body dynamics (MBD) were applied for two-way coupling for a dynamic balance simulation. The impact of particle size, friction coefficient, and restitution coefficient on energy dissipation in rotary compressors was evaluated, and the particle radius of 1 mm produced the most satisfactory. The experiment measured the vibrational acceleration in the tangential and radial directions at a particular duration and frequency to reflect the particle damper's dynamic balance and energy dissipation effect. Both simulation and experimental results confirmed that the novel design features are more acceptable than the original to satisfy the dynamic balance of a rotary compressor. [ABSTRACT FROM AUTHOR]

The accumulation of space debris is an ever-increasing problem. Systems that can reliably de-orbit (i.e., decrease the time to re-entry for) an inactive resident space object (RSO) are highly sought after. In this paper, we investigate the feasibility of utilizing the forces owing to the interaction of Earth's magnetic field with a permanent magnet that has been attached to an RSO in low Earth orbit. We consider an actively controlled permanent magnet that is optimally oriented to remove energy from the system, and the most favorable magnet-to-RSO mass ratio. We show that, even under these best-case assumptions, the interaction between a permanent magnet and Earth's magnetic field is not a viable means of de-orbiting an RSO. [Display omitted] • The interaction between a permanent magnet and Earth's magnetic field can be used to remove energy from an object in orbit. • The orientation of the permanent magnet can be controlled to optimize the energy loss. • This optimal orbital energy loss is not sufficient to de-orbit the object in a reasonable amount of time. • Interaction between a permanent magnet and Earth's magnetic field is therefore not a viable means for de-orbiting space debris. [ABSTRACT FROM AUTHOR]

To further improve the operating efficiency of linear induction motor, this paper proposes a loss minimization model predictive current control method based on governable loss online calculation. First, the method derives the equivalent circuit of linear induction motor containing independent iron loss branches, and establishes the loss model containing iron loss. Second, the expressions of stator d‐axis current with governable losses and secondary flux amplitude are derived from theoretical analysis, and then a given value of stator d‐axis current is derived when the governable losses are minimal. Then, a chain observer is designed to observe the secondary flux and calculate the governable loss and stator d‐axis current under the current operation. Finally, a method is proposed to introduce the stator d‐axis current observation results into the model predictive current control, which ensures the loss suppression effect and improves the dynamic performance at the same time. In addition, this article also compares the loss minimization controllers with or without iron loss. The simulation results are consistent with the theory, and the optimal control of the secondary flux of the linear induction motor can be successfully realized, thus effectively reducing the energy loss of the motor in the dynamic operation process. © 2024 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

A steel brace is effective to retrofit old reinforcement concrete (RC) buildings by increasing the horizontal load capacity of structures. However, concrete cracks that easily occur in the surrounding RC members under tension initiate early strength degradation, so this research aimed to develop a new self-centering brace (SCB) with the compression-only capacity such that no tension force is developed in the brace or to the adjoining RC members. Original SCBs have been developed to reduce the residual deformation of structures with a symmetrically flag-shaped hysteretic response. By altering the force transfer mechanism in the original SCB, a compression-only self-centering brace (C-SCB) can be developed under a symmetrically reversed cyclic loading, providing an alternative for the RC building retrofit. This paper first introduces the mechanics and deformation mechanism of the proposed C-SCB. A test program is then conducted on the cyclic tests of a buckling-restrained energy dissipating bar (EDB) to evaluate the energy dissipation. A 3,695-mm-long C-SCB is composed of posttensioning high-strength steel tendons, steel compression members, and buckling-restrained EDBs for the energy dissipation. The C-SCB in tests showed a good compression-only self-centering capability up to an axial displacement of 31 mm, with a maximum axial force of 1,530 kN. No damage of the steel tendons, compression members, or EDBs was found after three phase tests. Finite element analysis further validated the compression-only hysteretic response and mechanics of the C-SCB in a symmetrically reversed cyclic loading. [ABSTRACT FROM AUTHOR]

In this paper, we examine the impact of vehicles executing a full turn or U-turn in a single-lane roundabout system using a cellular automaton model. We investigate how increasing the number of these U-turning vehicles affects traffic flow characteristics and energy dissipation. Our findings reveal that as the prevalence of U-turning vehicles rises, the phase diagram undergoes significant changes; the maximum current phase expands, detrimentally impacting the free flow and congestion phases, while giving rise to a jamming phase. This shift results in a gradual increase in capacity at circulating lanes and a steady decline at entry/exit lanes. We also explore the role of aimless vehicles — those circulating without a fixed destination. As the proportion of such vehicles augments, it fosters an enlargement of the maximum current phase at the expense of the free flow and congestion phases. Furthermore, these vehicles influence energy dissipation across the three lanes of a roundabout. Significantly, we elucidate that variations in the percentage of these specific vehicular groups critically affect CO2 emissions. Our research unravels vital insights into optimizing roundabout management to enhance traffic flow and reduce environmental impact. [ABSTRACT FROM AUTHOR]

The mechanical response of granular materials, exemplified by frictional grain interactions, is characterized by a critical state in which deformation occurs without change of material volume or stresses when subjected to large shear deformation. In this work, a granular micromechanics approach (GMA) based continuum model is used to investigate the emergence of such a critical state. The continuum description is constructed through mechanical concepts based upon elastic and dissipation energies defined for a generic grain‐pair interaction. A hemivariational principle provides the basis for considering the evolution of damage and plasticity phenomena comprising grain‐pair contact loss and irreversible deformation. As a consequence, the Karush–Kuhn–Tucker (KKT)‐type conditions are derived, which give the evolution equations for the irreversible phenomena. Notably, in this derivation there is no invocation of flow rules and other similar assumptions of classical phenomenological continuum damage and plasticity. Further, Piola's ansatz is elaborated to kinematically connect granular micromechanics of grain‐pair to the continuum description. While the concept of critical state analysis has been handled with either phenomenological approaches or discrete numerical frameworks, in the present paper this concept is examined within a micromechanics‐based continuum description. The constitutive model is established and the coupled damage and plastic irreversible quantities are assessed. The critical state is shown to emerge as grain‐pair related damage and plastic evolution in a competitive/collaborative manner during the imposed loading path. [ABSTRACT FROM AUTHOR]

This paper presents a Hybrid Renewable Energy system combining multiple sources of renewable energy, such as PV, Wind, and energy storage devices, to provide a reliable and sustainable power supply. Cascaded converters are used to efficiently transform and manage the energy from these sources. To achieve optimal performance and reliable operation, a real-time closed-loop control algorithm is designed and implemented for the cascaded converter. The control algorithm facilitates the smooth integration of energy from various renewable sources, optimizing the utilization of available resources and ensuring a consistent power supply. The algorithm maximizes the energy conversion efficiency of the cascaded converter, reducing energy losses and minimizing waste. It also optimizes the integration of renewable sources, regulates output parameters, and ensures efficient energy conversion. [ABSTRACT FROM AUTHOR]

In this paper, electronic properties of Janus MSX monolayers (M = Mo, W; X = Se or Te), including electron energy loss near edge structures (ELNES), as K and L2,3 edge spectra of sulfur atoms, have been calculated using a full potential scheme and the augmented plane wave plus local orbitals (APW+lo) method in the framework of density functional theory (DFT). Due to the lack of experimental results, the obtained spectra are compared with the corresponding spectra of MoS2 monolayer. The band structure analysis shows that the Janus MoSSe and WSSe monolayers are direct bandgap semiconductors, while the Janus MoSTe and WSTe monolayers are indirect bandgap semiconductors. In comparison to MoS2, the main structures of the K edge ELNES spectra of sulfur atoms in Janus monolayers occur at lower energies, due to the structural change and increased bond length. The relative reduction of intensities in the main structures predicts the possibility of reducing the number of partial densities of states (PDOS), that is, the reduced p PDOS for the K edge in the corresponding energy range. In the K (L2,3) edge ELNES spectra of the sulfur atom in Janus monolayers and MoS2 monolayers, the main structures are due to the electron transfer to the unoccupied px+py and pz states (3s of sulfur and 4d states of the transition metal). [ABSTRACT FROM AUTHOR]

In this paper, a physical index for quantitatively evaluating the non-proportional damping characteristics is proposed. Additionally, a direct design approach applicable to composite isolated structures (consisting of an upper damping structure and a base isolation system) is proposed for performance analysis of practical three-dimensional non-proportional damped structures. Furthermore, the elastic–plastic behavior of the structure under acceleration excitation is considered to determine the structural damage and response, improving computational accuracy and providing better solutions for the analysis and design of composite isolated structures. Analysis studies have shown that under rare and extremely rare earthquake events, structures designed using the complex modal response spectrum method (CM-RSM) exhibit less damage compared to those designed using the forced decoupling response spectrum method (FD-RSM) compared to the results obtained using the complex modal response spectrum method. For the seismic performance study of non-proportional damped structures, it is recommended to use the complex modal response spectrum method. With an increasing earthquake intensity, the proportion of energy dissipation due to the nonlinear strain energy dissipation of a structure increases, and the proportion of energy dissipation due to the isolators and dampers in the damping energy portion decreases. [ABSTRACT FROM AUTHOR]

The shear wall system with cast‐in situ concrete infilled walls has been widely used in high‐rise buildings due to its significant advantages in construction. In this paper, quasi‐static tests were conducted on the shear walls with and without cast‐in situ concrete infilled walls to analyze their failure modes, load‐bearing capacity, stiffness, energy dissipation capacity, and ductility. A simplified model of the shear wall with cast‐in situ concrete infilled walls was proposed based on the fiber element model in OpenSees. The test results showed that the shear wall specimens with cast‐in situ concrete infilled walls exhibited full‐section compression or tension failure, and the cast‐in situ concrete infilled walls did not show obvious damage. Compared with the shear wall without infilled walls, the overall stiffness, load bearing capacity, and energy dissipation capacity of the shear wall specimens with cast‐in situ concrete infilled walls improved, indicating better seismic performance than those without infilled walls. Comparison between the hysteresis and skeleton curves derived from the tests and those simulated by the proposed simplified model revealed errors within 15% for stiffness, yield bearing capacity, and ultimate bearing capacity for shear walls with cast‐in situ concrete infill walls, affirming the effectiveness and accuracy of the model. [ABSTRACT FROM AUTHOR]

This paper emphasizes the integration of wind and photovoltaic (PV) generation with battery energy storage systems (BESS) in distribution networks (DNs) to enhance grid sustainability, reliability, and flexibility. A novel multi‐objective optimization framework is introduced in this study to minimize energy supply costs, emissions, and energy losses while improving voltage deviation (VD) and voltage stability index (VSI). The proposed framework comprising normal boundary intersection (NBI) and decomposition‐based evolutionary algorithms (DBEA) determines the optimal siting and sizing of renewable‐based distributed resources, considering load demand variations and the intermittency of wind and solar outputs. The comparative analysis establishes that the proposed strategy performs better than many contemporary algorithms, specifically when all the objective functions are optimized simultaneously. The validation of the proposed framework was carried out on the standard IEEE‐33 bus test network, which demonstrates significant percentage savings in energy supply costs (49.6%), emission rate (62.2%), and energy loss (92.3%), along with enormous improvements in VSI (91.9%) and VD (99.8953%). The obtained results categorically underline the efficiency, reliability, and robustness of the proposed approach when employed on any complex distribution network comprising multiple renewable energy sources and battery storage systems. [ABSTRACT FROM AUTHOR]

This paper presents a size‐dependent energy‐based strain burst criterion linking strength, elasticity, fracture energies and specimen size effect with stress state due to changes in boundary conditions. It proposes the concept of a 'Burst Envelope', a surface in three‐dimensional principal stress space derived based on energy storing and dissipation characteristics of a rock sample, taking into account the size of the specimen and potential localised failure pattern. A scalar burst index is also proposed to quantify the bursting scale. To illustrate and verify its functioning, a numerical modelling framework based on the distinct element method and employing a new cohesive‐frictional contact model is used to perform virtual strain burst experiments under different polyaxial loading‐unloading scenarios, mimicking various underground excavation scenarios. The obtained results are in good agreement with the theoretical prediction of burst occurrence. On that basis, the variation of burst possibility and magnitude are investigated with key factors, including confinement level and the material's elastic, strength and fracture properties. The effect of the specimen's aspect ratio and size on the rock burst potential is elaborated and verified using virtual strain burst experiments, facilitating the linking of the proposed theoretical framework with the evaluation of in‐situ strain bursts in rock masses around underground openings. [ABSTRACT FROM AUTHOR]

In this paper, we first propose and study the second-order time-discrete numerical scheme for the sixth-order nonlinear parabolic problem of the square phase-field crystal model. Then, we demonstrate the two-step backward differentiation formula (BDF-2) scheme with mass conservation and energy dissipation, where the higher order nonlinear term is treated implicitly. Moreover, a rigorous error analysis is presented and we prove the optimal second-order convergence rate O (τ 2) in H 1 - norm, where τ is the time step. Finally, some numerical results are provided to confirm our theoretical analysis. [ABSTRACT FROM AUTHOR]

This paper assesses thermoelastic damping (TED) in circular nanoplates by incorporation of the small-scale effect into structural and thermal domains. The nonlocal elasticity theory and dual-phase-lag (DPL) heat conduction model are exploited for achieving the size-dependent coupled thermoelastic equations. By choosing time-harmonic and asymmetric form for deflection and temperature change, and solving the size-dependent thermoelastic eigenvalue problem, the damped natural frequency of circular nanoplate is extracted. On the basis of the complex frequency approach, an analytical relation, for the description of TED in circular nanoplates, is derived. For different boundary conditions and vibration modes, a comparison study is performed between the size-dependent results and those provided by classical continuum mechanics and heat conduction theories. Outcomes show a discrepancy between results acquired by the size effect on the structure and heat conduction. It is elucidated that how nonlocal and DPL characteristic parameters can represent the size-dependent phenomenon and can affect the magnitude of TED. A comprehensive parametric study is conducted to specify the influence of boundary constraints, vibration mode and the type of material on the amount of energy loss from TED. [ABSTRACT FROM AUTHOR]

The liquid natural gas (LNG) submerged pump is the core fluid transportation equipment in the LNG industry. The analysis of energy loss and flow characteristics can improve its performance. In this paper, the flow field is numerically simulated for a LNG cryogenic multistage pump and the energy loss is quantitatively evaluated using entropy generation theory. For each stage, there are significant differences for the energy loss and fluid flow at low flow rates, but they are basically the same except for the first stage when the operating flow rate is greater than 0.8Qd. The higher entropy generation appears in the gap between the impeller and the guide vane. In the first-stage impeller passage and import, the entropy generation is distinctly lower than that in other stages because the circumferential velocity gradient is reduced by the inducer pre-rotation. Meanwhile, as the shear force of the blade on the fluid weakens, the vortex at the first stage impeller can also be decreased. However, it has little effect on the energy loss caused by rotor–stator interaction at the impeller outlet. [ABSTRACT FROM AUTHOR]