bluuebunny/crossref_metadata_2025 huggingface dataset:
A rapid multi-modal parameter estimation technique for LISA
Authors: Hoy Charlie , Weaving Connor R , Nuttall Laura K , Harry Ian
Published: November 2024

The laser interferometer space antenna (LISA) will observe gravitational-wave (GW) signals from a wide range of sources, including massive black hole binaries (MBHBs). Although numerous techniques have been developed to perform Bayesian inference for LISA, they are often computationally expensive; analyses often take at least ∼1 month on a single CPU, even when using accelerated techniques. Not only does this make it difficult to concurrently analyse more than one GW signal, it also makes it challenging to rapidly produce parameter estimates for possible electromagnetic follow-up campaigns.simple-pewas recently developed to produce rapid parameter estimates for GW signals observed with ground-based GW detectors. In this work, we extendsimple-peto produce rapid parameter estimates for LISA sources, including the effects of higher order multipole moments. We show thatsimple-peinfers the source properties of massive black hole binaries in zero-noise at least∼100×faster than existing techniques;∼12 h on a single CPU. We further demonstrate thatsimple-pecan be applied before existing Bayesian techniques to mitigate biases in multi-modal parameter estimation analyses of MBHBs.
Total resonant terahertz absorption enabled by large-scale adjustable admittance inverse matching in a metal groove with graphene
Authors: Morozov Mikhail Yu , Popov Vyacheslav V
Published: November 2024

We propose a tunable terahertz (THz) perfect absorber based on a metal groove with a graphene-loaded dielectric resonator, and theoretically study its basic properties. The proposed absorber allows switching between the regimes of perfect absorption at the Fabry–Pérot resonance excited near the cutoff frequency of the metal groove and almost total reflection away from the resonance by changing the Fermi energy in the graphene. For this purpose, we propose a ‘bottom–up’ approach, which is based on tuning the admittance of the input line (the metal groove in our case) instead of the structure admittance in order to reach the perfect admittance-matching condition. We demonstrate that this effect can be realized at arbitrarily selected frequencies in the entire THz range due to the dispersion of incoming waves in the metal groove, which ensures the large-scale tunability of its characteristic admittance. As a result, total absorption can be realized in the Fabry–Pérot resonance even in a simple graphene-loaded dielectric cavity for any admittance of the graphene layer, which is advantageous compared to the majority of existing THz absorbers with more complicated designs.
Band gap engineering and photoelectronic properties of novel pentagonal materials penta-XN2 (X = Ni, Pt): a first principle calculations
Authors: Han Keyan , Huang Lin , Luo Cheng , Qin Danfeng , Yang Wenhao , Xu Liang , Long Mengqiu , Chen Tong
Published: November 2024

Two-dimensional pentagonal materials as the next-generation nanoelectronic devices are promising candidates due to their interesting structures and novel electronic, mechanical, optical and other properties. Penta-NiN2, a newly synthesized material with pentagonal atomic arrangement under high pressure (ACS Nano 15 (2021), 13 539), has also sparked considerable interest. This study systematically investigates the effects of the biaxial strain on the electronic structure of monolayer penta-NiN2 (penta-PtN2). Furthermore, combining the non-equilibrium Green’s function approach, we research the optoelectronic and transport properties of penta-NiN2 (PtN2). The results indicate that biaxial strain can effectively modulate the bandgap of penta-NiN2 (PtN2), particularly achieving a semiconductor-to-metal transition under compressive strain. Moreover, tensile and compressive strains effectively enhance the optical characteristics of penta-NiN2 (PtN2) in visible light range. Under tensile and compressive strains, the absorption peak of penta-NiN2 shows a red shift and a blue shift in visible region, respectively. The pin-junction photodiode of penta-NiN2 (PtN2) exhibit significant photocurrent under illumination. The strongest photocurrent is observed in penta-NiN2 photodiodes under −3% compressive strain, showing the highest response to yellow light. Under the tensile stress of 7% and compressive stress of −3%, the photocurrent of the Penta-PtN2 photodiode is enhanced in the yellow and green light regions. Additionally, applying compressive strain reduces the bandgap of penta-NiN2 (PtN2), significantly enhancing its transport properties and thereby inducing a switch effect in devices. In summary, our study demonstrates that penta-XN2 (X = Ni, Pt) is a promising material in the fields of nanoelectronics and optoelectronic devices.
Impact of reactor neutrino uncertainties on coherent scattering's discovery potential
Authors: Hayen Leendert
Published: November 2024

Nuclear power reactors are the most intense man-made source of antineutrino's and have long been recognized as promising sources for coherent elastic neutrino-nucleus scattering (CE$\nu$NS) studies. Its observation and the spectral shape of the associated recoil spectrum is sensitive to a variety of exotic new physics scenarios and many experimental efforts are underway. Within the context of the reactor antineutrino anomaly, which initially indicated eV-scale sterile neutrino's, the modeling of the reactor antineutrino spectrum has seen a significant evolution in the last decade. Even so, uncertainties remain due to a variety of nuclear structure effects, incomplete information in nuclear databases and fission dynamics complexities. Here, we investigate the effects of these uncertainties on one's ability to accurately distinguish new physics signals. For the scenarios discussed here, we find that reactor spectral uncertainties are similar in magnitude to the projected sensitivities pointing towards a need for $\beta$ spectroscopy measurements below the inverse $\beta$ decay threshold.
Rolling bearing fault diagnosis model based on external attention integrated convolutional neural network under imbalanced data conditions
Authors: Yang Jing , Luo Yanbo , Huang Gangjin
Published: November 2024

Rolling bearings are essential components in numerous mechanical systems, and their failure can result in considerable downtime and expensive repairs. Therefore, accurate and timely fault diagnosis is vital for effective predictive maintenance and overall reliability. Traditional diagnostic methods often struggle with complex and non-stationary signals, compounded by issues of data imbalance in real-world scenarios. A method for diagnosing rolling bearing faults has been developed in this paper utilizing external attention (EA), convolutional neural networks (CNN), and continuous wavelet transform (CWT), specifically addressing the challenge of imbalanced sample data. This approach offers significant advantages, including a reduction in complexity by eliminating the need for data augmentation and leveraging EA for enhanced feature extraction from samples. Compared to other attention mechanisms, this method demonstrates outstanding performance on both training and testing sets with imbalanced samples, exhibiting minimal overfitting tendencies. The proposed CWT-EACNN method effectively addresses the challenge of imbalanced sample data in rolling bearing fault diagnosis, demonstrating exceptional performance and reduced complexity.
On convergence of linear response formulae in some piecewise hyperbolic maps
Authors: Wormell Caroline L
Published: November 2024

When high-dimensional non-uniformly hyperbolic chaotic systems undergo dynamical perturbations, their long-time statistics are generally observed to respond differentiably with respect to the perturbation. Although important in applications, this differentiability, which is thought to be connected to the dimensionality of the system, has remained resistant to rigorous study outside of the one-dimensional setting. To model non-uniformly hyperbolic systems in multiple dimensions, we consider a family of the mathematically tractable class of piecewise smooth hyperbolic maps, the Lozi maps. For these maps, we prove that the existence of a formal derivative of the response reduces to conditional mixing of the SRB measure on the singularity set. Heuristically, this suggests that Lozi maps, and piecewise uniformly expanding maps more generally, should have linear response.
Elliptical orbits
Authors: Cross Rod
Published: November 2024

Planets and satellites follow elliptical orbits and so does the bob of a conical pendulum. Typical orbits for a conical pendulum are calculated and compared with experimental results. Kepler’s first two laws apply to a conical pendulum but not the third law.
The ‘Universe in a Box’: a hands-on activity to introduce primary school students to cosmology
Authors: Tuveri Matteo , Steri Arianna
Published: November 2024

Physics Education Research shows that active learning and interdisciplinary strategies can enhance students’ engagement in physics. In primary school, the implementation of active learning pedagogies such as Inquiry-Based Science Education aims to encourage students’ autonomy and participation in their learning process. Indeed, active learning promotes pupils’ creativity, helping them develop the skills that increasingly determine their future employability and personal development, introducing them to STEM. In this regard, stories and storytelling can help improve teaching and students’ physics learning. Telling the Universe and its history can afford this job. The Big Bang, the Cosmic Microwave Background, and the formation of stars and planets are valuable tools for introducing primary school students to physics and the scientific method while fostering their curiosity about science. Moreover, it helps the instructors monitor the development of peculiar misconceptions on these topics, preventing them from fully understanding physics phenomena. In this paper, we present an innovative short-term program (one session of three hours) called ‘The Universe in a Box’ to introduce primary school students (grades 4–5, ages 9–10) to cosmology. We illustrate our design and the educational purposes of the program and present the outcomes from its implementation in five different laboratories in Sardinia, Italy, from 2022 to 2024 (60 students involved). This work can furnish a theoretical and methodological guide for primary school teachers and instructors on integrating formal curricula with contemporary physics topics using interdisciplinary approaches, engaging their students in STEAM (STEM plus Arts).
Assessment of arteriosclerosis based on lognormal fitting
Authors: Tang Hao , Li Yumin , Zhao Lulu , Xiang Tenghui , Zhang Ziqi , Li Jianqing , Liu Chengyu
Published: November 2024

Objective. Pulse pressure waves contain information about human physiology. There is a need for a simple, accurate way to know cardiovascular health in the clinic, so as to realize the implementation of convenient and effective early health monitoring for patients with arteriosclerosis. Approach. This study proposes an arteriosclerosis assessment method based on fitting a lognormal function, along with improving a conventional electronic sphygmomanometer. During the deflation phase of blood pressure measurement, the cuff pressure was kept constant (40 mmHg) and an additional 10 s of pulse signal was acquired. To derive the pulse pressure waveforms for a single cycle, the acquired pulse data of 101 cases were preprocessed in this study, including filtering for noise removal, onset point identification, removal of baseline drift, and normalization. In this study, an improved pulse resolution algorithm is proposed for the multimodal problem of the pulse wave, combining waveform matching and threshold setting, and finally obtaining the resolution parameters of the lognormal function with an average error less than 1.5%. Main results. According to the correlation analysis, the resolved parameters A
1, W
2, C
2, W
3, and C
3 were significantly correlated with brachial-ankle Pulse Wave Velocity, and the absolute correlation range in 0.17–0.53, which can be used as a reference index for arteriosclerosis. An arteriosclerosis assessment model was constructed based on the support vector mechanism, and the prediction accuracy was 91.1%. Significance. This study provides a new solution idea for the arteriosclerosis assessment method as well as the pulse resolution algorithm, which has a greater reference value.
Synthesis, characterization, and study of linear and non-linear optical properties of some newly thieno[2,3-b]thiophene analogs
Authors: Abd El-Lateef Hany M , Kamel Moumen S , Alzahrani Abdullah Yahya Abdullah , Khalaf Mai M , Gouda Mohamed , Ali El-Remaily Mahmoud Abd El Aleem Ali
Published: November 2024

New 3,4-diaminothieno[2,3-b]thiophene derivatives were synthesized by attaching with different aromatic have rich electron. The resulting compounds have been investigated by FT-IR, NMR, elemental analysis and optical absorption spectra. Comparison between the resulting compounds revealed that oxoindolin-3-ylidene)amino)thieno[2,3-b]thiophene has the highest absorption peak intensity at

∼

696

nm

. Thin films have been prepared by thermal evaporation technique and characterized by UV-visible-NIR spectroscopy and the associated absorption, dielectric and dispersion parameters have been investigated and compared with other reported results. The obtained results indicated that diethyl 3,4-bis(((E)-2-oxoindolin-3-ylidene)amino)thieno[2,3-b]thiophene-2,5-dicarboxylate and 3,4-bis(((E)-2-oxoindolin-3-ylidene)amino)thieno[2,3-b]thiophene-2,5-dicarbonitrile have manifested small band energy gap energy 1.95 eV and 1.66 eV, respectively, as a result of increasing conjugation and high absorption coefficient, making these compounds ideal for use in solar cells. The high nonlinear parameters such as refractive index and third-order nonlinear susceptibility of these organic compound thin films are significantly asymptotic compared to chalcogenide and oxide materials, making them suitable for nonlinear optical devices.
Investigation on influence factors of optically controlled electrorheological fluid damping system
Authors: Yao Yao , Wang Xinjie , Liu Zhicheng
Published: November 2024

Electromagnetic rheological damping control system, as an important control technology, has been widely used in braking, vibration reduction, micro-valve etc. However, the electromagnetic rheological damping control system faces electromagnetic interference because of the high-voltage source. To solve this problem, a novel optically controlled electrorheological fluid damping system was proposed in this study. Previous studies have confirmed the feasibility of the optically controlled electrorheological fluid damping control system via numerical simulation and experiment. In this paper, the mechanism and mathematical model of the optically controlled electrorheological fluid damping system are established. Analyses of influencing factors of the optically controlled damping system, especially the impact of light intensity and microchannel size on system performance, are performed through experimental and theoretical methods. Research findings of the analyses of influencing factors provide a comprehensive understanding of the working principle of the electrorheological fluid damping system, thereby promoting stability and reliability in microfluidic technology.
Compact size and wideband 4 × 4 MIMO antenna for 5G NR networks
Authors: Yousef Basma M , Ameen Allam M , Ali Wael A E , Ibrahim Ahmed A , M A Abdelhady , Ahmed Ashraf E
Published: November 2024

In this paper, a crescent-shaped four-port MIMO is proposed to deploy in 5 G wireless network coverage with the advantages of wide bandwidth. The MIMO antenna is printed on an RO4003 substrate (ε
r = 3.55) with a thickness of 0.203 mm and a rectangular slot in the ground plane to obtain the desired performance. The antenna is duplicated two times in an orthogonal arrangement to achieve 4 ports MIMO antenna for capacity improvement purposes. The antenna satisfies an impedance bandwidth of 20 GHz (20.5–40.5 GHz) with an isolation of ≥22 dB. Furthermore, the suggested 4-port MIMO antenna is fabricated and tested to validate the simulated outcomes, and good consistency between results is achieved in terms of scattering parameters, radiation patterns, gain, and diversity parameters. The presented 4-port MIMO antenna is considered a good candidate for future 5 G NR networks due to its competitive advantages.
Electronic structure, elasticity, magnetism of Mn2X In (X = Fe, Co) full Heusler compounds under biaxial strain: First-principles calculations
Authors: Gao 皋 Shiran 世苒 , Zhao 赵 Chengyang 成洋 , Zhang 张 Xinzhuo 欣卓 , Qiao 乔 Wen 文 , Yan 颜 Shiming 士明 , Bai 白 Ru 茹 , Zhou 周 Tiejun 铁军
Published: November 2024

The electronic structure, elasticity, and magnetic properties of the Mn2
X In (X = Fe, Co) full-Heusler compounds are comprehensively investigated via first-principles calculations. The calculated elastic constants indicate that both Mn2FeIn and Mn2CoIn possess ductility. At the optimal lattice constants, the magnetic moments are found to be 1.40 μ
B/f.u. for Mn2FeIn and 1.69 μ
B/f.u. for Mn2CoIn. Under the biaxial strain ranging from −2% to 5%, Mn2FeIn demonstrates a remarkable variation in the spin polarization, spanning from −2% to 74%, positioning it as a promising candidate for applications in spintronic devices. Analysis of the electronic structure reveals that the change in spin polarization under strain is due to the shift of the spin-down states at the Fermi surface. Additionally, under biaxial strain, the magnetic anisotropy of Mn2FeIn undergoes a transition of easy-axis direction. Utilizing second-order perturbation theory and electronic structure analysis, the variation in magnetic anisotropy with strain can be attributed to changes of d-orbital states near the Fermi surface.
Darboux transformation, positon solution, and breather solution of the third-order flow Gerdjikov–Ivanov equation
Authors: Liu 刘 Shuzhi 树芝 , Li 李 Ning-Yi 宁逸 , Dong 董 Xiaona 晓娜 , Li 李 Maohua 茂华
Published: November 2024

The third-order flow Gerdjikov–Ivanov (TOFGI) equation is studied, and the Darboux transformation (DT) is used to obtain the determinant expression of the solution of this equation. On this basis, the soliton solution, rational solution, positon solution, and breather solution of the TOFGI equation are obtained by taking zero seed solution and non-zero seed solution. The exact solutions and dynamic properties of the Gerdjikov–Ivanov (GI) equation and the TOFGI equation are compared in detail under the same conditions, and it is found that there are some differences in the velocities and trajectories of the solutions of the two equations.
On load dependence of detachment rate of kinesin motor
Authors: Shi 史 Xiao-Xuan 晓璇 , Wang 王 Yao 瑶 , Liu 刘 Yu-Ru 玉如 , Xie 谢 Ping 平
Published: November 2024

Kinesin is an archetypal microtubule-based molecular motor that can generate force to transport cargo in cells. The load dependence of the detachment rate is an important factor of the kinesin motor, the determination of which is critically related to the chemomechanical coupling mechanism of the motor. Here, we use three models for the load dependence of the detachment rate of the kinesin motor to study theoretically and numerically the maximal force generated and microtubule-attachment duration of the motor. By comparing the theoretical and numerical results with the available experimental data, we show that only one model can explain well the available experimental data, indicating that only this model can be applicable to the kinesin motor.
Chiral phonons of honeycomb-type bilayer Wigner crystals
Authors: Yang 杨 Dingrui 丁睿 , Li 李 Lingyi 令仪 , Zhang 张 Na 娜 , Yu 俞 Hongyi 弘毅
Published: November 2024

We theoretically investigated the chiral phonons of honeycomb-type bilayer Wigner crystals recently discovered in van der Waals structures of layered transition metal dichalcogenides. These chiral phonons can emerge under the inversion symmetry breaking introduced by an effective mass imbalance between the two layers or a Moiré potential in one layer, as well as under the time-reversal symmetry breaking realized by applying a magnetic field. Considering the wide tunability of layered materials, the frequencies and chirality of phonons can both be tuned by varying the system parameters. These findings suggest that bilayer honeycomb-type Wigner crystals can serve as an exciting new platform for studying chiral phonons.
Spectroscopy of excited quarkonium states in the light-front quark model*
Authors: Acharyya Ritwik , Puhan Satyajit , Dahiya Harleen , Kumar Narinder
Published: November 2024

We investigated the ground state (1S), radially excited states (2S) and (3S), and orbitally excited state (1P) for the heavy charmonia (

) and bottomonia (

) mesons in the light-front quark model (LFQM). The light-front wave functions have been successful in explaining various physical properties of meson states in the past, especially for the 1S and 2S states. However, the radially excited state 3S and orbitally excited state 1P have rarely been investigated. In this study, we considered these two excited states and investigated the electromagnetic form factors (EMFFs), charge radii, decay constants, parton distribution functions (PDFs), and the distribution amplitudes (DAs) for the quarkonia system. For the sake of completeness, we also studied the ground and the first excited states of quarkonia mesons. We also illustrated the 3D wave functions for the radially excited states to study their nodal structures.
Time-dependent full-radius integrated modeling of the DTT tokamak main plasma scenarios
Authors: Bonanomi N. , Luda T. , Mantica P. , Auriemma F. , Balbinot L. , Castaldo A. , Innocente P. , Rubino G. , Ambrosino R. , Angioni C. , Casiraghi I. , Fajardo D.
Published: November 2024

We use an integrated modeling workflow with the transport code ASTRA coupled with the quasi-linear transport model TGLF-SAT2, the neoclassical model NCLASS, the FACIT model for the neoclassical impurity transport and the IMEP routines for the pedestal calculations, in order to predict the evolution of the plasma profiles for the Divertor Tokamak Test facility (DTT) tokamak main scenarios. The simulations cover the whole confined plasma radius, up to the separatrix, and the time evolution of the plasma including the early phase in limiter configuration, the whole current ramp-up phase in L-mode divertor configuration, the L–H transition and part of the stationary H-mode phase. Six fields are predicted, i.e. the ion and electron temperatures, the electron density, two impurity densities and the plasma current. The simulations indicate that the main DTT scenarios are within the technical capabilities of the machine. They also indicate that the DTT full power, full current, full field scenario will be able to operate in H-mode with a duration of the flat-top phase of the order of ∼ 30 s, and plasma parameters allowing a core-edge integrated study of the power exhaust, which is the main mission of the device. The simulations show also a strong flexibility of the DTT plasmas, that allows DTT to study reactor-relevant conditions unexplored by existing tokamaks.
Definition of a Baseline Rotor Design for a 25MW Floating Offshore Wind Turbine
Authors: Escalera Mendoza Alejandra S. , Todd Griffith D. , dos Santos Carlos R. , Abdelmoteleb Serag-Eldin , Bachynski-Polić Erin E. , Oggiano Luca
Published: November 2024

Wind turbine sizes have grown rapidly in recent years with machine ratings of 15-16 MW available from multiple manufacturers for offshore wind turbines. While the industry advances large-scale turbine designs, offshore developers have initially focused on siting in shallow waters on bottom-fixed foundations; however, eyes are also on deep-water locations where floating systems are required. The present study presents the definition for an initial baseline rotor design at 25 MW scale, designed for a floating offshore system. The purpose of this paper is to document this 25 MW blade definition for use as a reference design for future floating wind technology development by industrial and academic researchers and developers. As this is an initial reference design, some opportunities (and plans) for further mass or cost reduction are also noted. In summary, the paper documents the initial baseline rotor design including aerodynamic and structural design of the rotor blades, along with key details about the control system and floating system designs for the floating 25 MW wind turbine system.
Analysing a grid-forming storage hub for an offshore platform cluster supplied by wind energy
Authors: Santos Mota Daniel dos , Haugdal Hallvar , Chabaud Valentin
Published: November 2024

This paper performs an analysis of the electrification of an of-the-grid offshore oil and gas cluster of six platforms by means of a wind farm combined with a hydrogen energy hub. The latter, whose model is made publicly available, contains a grid-forming battery system and grid-following electrolysis and fuel cells units. State-of-the-art aerodynamic simulations are used for representing the wind farm power output, which encompasses wake losses and correlated wind fuctuations between turbines arising from farm-scale turbulence. One of the offshore platforms is represented by a detailed publicly available model named LEOGO. The other five platforms are represented as aggregated mixes of constant power and constant impedance loads. The computer simulations presented in the paper provide valuable insights into furthering the design and optimization of the hub concept. These insights include, among others, sizing of batteries depending on maximum ramp rates of fuel cells and electrolysers, identifying and mitigating instabilities induced by interactions among power electronic converters, and evaluating the consequences for the converters when those contribute with voltage support at the hub.
Flow observations using nacelle lidars: A study on the University of Stavanger campus
Authors: Vogt L , Jakobsen J B , Snæbjörnsson J T , Li L , Obhrai C , Roemer S
Published: November 2024

This study deals with wind measurements on the campus of the University of Stavanger, using two continuous-wave nacelle lidars and a vertical continuous-wave profiler. Wind data is further acquired by 2-D sonic anemometers fixed to the lidars. The emphasis of the analysis is on the data gathered by the nacelle lidars. The horizontal wind speeds reconstructed from the radial velocities are compared to the recordings of the sonic anemometers and analysed in terms of mean wind profiles over the extent of the scanning circle. Standard logarithmic and power laws are fitted to the profiles to estimate site-specific parameters such as wind shear exponent and surface roughness. Turbulence characteristics in the mean wind direction, such as spectra and variances, are estimated and compared to those from the sonic anemometer. The study demonstrates the overall potential of remote sensing for wind monitoring in an urban environment. The wind velocities acquired in the individual measurement points along the nacelle lidars’ scanning circles are found to capture the flow in the monitored regions around the buildings in a realistic way. Together with the information from the vertically pointing wind profiler, the measurement data represents a valuable source for validation of related numerical models for flow in an urban area.
Experimental investigation of the relation between operating conditions and offshore wind turbine drivetrain dynamics
Authors: Kestel K , Peeters C , Vratsinis K , Matthys J J , Sterckx J , Daems P J , Helsen J
Published: November 2024

This study investigates the impact of operating and environmental conditions on the vibration induced on an offshore wind turbine drivetrain. Furthermore, it explores the role of the dynamic response of the global wind turbine structure to vibration on the drivetrain. A prolonged experimental campaign dedicated to condition monitoring the drivetrain provides experimental vibration signals. These vibration signals are acquired under varying operating conditions across multiple locations of an offshore wind turbine drivetrain of a Belgian Offshore Wind farm and serve as the basis for analysis. The signals’ statistics facilitate establishing connections between dynamic behaviour and operational variables, such as active power, rotor speed, blade pitch angle, and turbulence intensity, sampled at every second and provided by Fast-SCADA. The initial phase of the analysis involves a comprehensive examination of various statistical properties of the vibration signals to link the drivetrain’s dynamic response to operational conditions. This exploration includes both active and standstill periods of the wind turbine. A comprehensive summary that relates the global vibration characteristics with the operating conditions is formed by scrutinizing the overall vibration signals. In the study’s second phase, a detailed investigation is conducted on the vibration signals recorded during standstill conditions. Investigation of standstill data ensures that the structural modes’ spectral content does not interfere with the machines’ kinematic content. The analysis of standstill data proceeds from determining the most energetic resonance frequencies through the average power spectral density of the vibration signals. These identified frequency bands enable a thorough exploration, revealing the interlink between the offshore wind turbine drivetrain’s dynamic response and the operating/environmental conditions.
Optimal experimental design for identification of hydrodynamic loading models
Authors: Stamenov D , Abbiati G , Sauder T
Published: November 2024

Hydrodynamic model-scale experiments are an intrinsic part of the design of marine structures, as they enable validating and calibrating the involved hydrodynamic numerical models. Such seakeeping experiments are generally conducted using a simple spring-based mooring system, with fixed properties throughout the tests. In the context of cyber-physical testing, the marine structure is kept in position in the laboratory by a virtual mooring system, the properties of which can be adjusted on the fly. This paper provides an algorithmic approach for maximizing the information gain from the test by optimizing the mooring stifness and damping parameters that define the experiment. The method is verified with synthetic data generated for the INO Windmoor 12MW floater, and is shown to be robust to noise and unmodeled effects.
Coordinated control of single-point moored floating multi-wind turbines under fault events and shutdowns
Authors: Eguinoa Irene , Martín-San-Román Raquel , Sandua-Fernández Iñaki , González-Lope Rubén , Azcona-Armendáriz José
Published: November 2024

The emergence of novel concepts aimed at the reduction of floating offshore wind energy cost is increasingly demanding new control approaches. This is the case of floating offshore multi-wind turbine assets (FOMWT), with two or more full wind turbines placed on the same floating platform. The strong dynamic interaction among the sub-components of such systems requires appropriate coordination of the commands driven by the individual wind turbine controllers. The impact of such coupling may increase depending on the asset confguration, as is the case of single-point distribution of mooring lines, commonly applied to FOMWTs. Among the most demanding situations are those under fault events and shutdowns, which may cause large uncontrolled platform rotation and put the system integrity at risk. To address this, a new coordinated control level, mastering the individual turbine controllers hierarchically, is proposed to govern the whole asset. The control concept proves to be effective under a reduced set of extreme load cases in accordance with standards for a two-wind turbine FOMWT. The simulations are performed with the multi-wind turbine simulation tool MUST, which accounts not only for the interaction among the two turbines and the platform, but also for the communication of the coordinated control and the individual turbine control levels.
Floating offshore wind – an overview of marine spatial planning and the needs of the industry
Authors: Dvorak O , Bohan G , Incecik A , Ingram D , Ashton I , Konovessis D
Published: November 2024

The International Energy Agency (IEA) Wind Task 49 aims to accelerate the commercialisation of floating wind. Work package 4 of the task analyses and incorporates the views of key stakeholders to ensure the Task is aligned with industrial needs. Work package 4 is broadly split into innovation management and marine spatial planning (MSP). The innovation management section evaluates the potential social, environmental and economic impact of floating wind innovations by surveying a multidisciplinary group of stakeholders to ask them to compare the potential impact of identified innovations. The survey results will inform a scored ranking of floating wind innovations, and the future research directions for the Task. In the MSP section representatives from partner countries are interviewed to assess their domestic offshore wind sector and discuss the approach the country has taken to MSP, with a focus on floating wind. The other explored parameters include MSP regulations, offshore wind policy and targets, supply chain capabilities, and environmental and fisheries impact assessments. A synthesis of what stakeholders perceive as impactful innovation, and an understanding of the direction of the industry and policy can be built from the two parts. This paper describes the methodology used to create this synthesis and findings from the first year of work are shared.
Research on detection and protection technology of DC residual current
Authors: Yang Ruixiong , Chen Yong , Xu Kai , Gao Shuping
Published: November 2024

To realize that the residual current device can accurately and quickly detect the fault when the fluctuating DC residual current occurs in the system and improve the system’s safety, a DC residual current detection and protection method based on VMD was proposed. Particle Swarm Optimization (PSO) was used to optimize the penalty factor and the number of decomposition layers of VMD. The minimum envelope entropy of the residual current signal is used as the fitness function to obtain the optimal combination. The criterion of fault occurrence is established based on the optimal modal component mutation characteristic of the residual current decomposed by VMD. Experiments show that this method can identify faults quickly and effectively when pulsating DC residual current is generated in the system.
Human-machine collaborative inspection of transmission corridors based on the BeiDou positioning
Authors: Xu Zhenlei
Published: November 2024

Inadequate inspection performance of transmission lines leads to damages, posing threats to the safety of power grids. To enhance the efficiency of transmission line inspection and to reduce safety hazards, a method based on the BeiDou positioning for human-machine collaboration in transmission line inspection is proposed. Drones equipped with then BeiDou positioning are utilized to collect transmission line data via the Web Mercator projection, determining the inspection routes. Fault parameters of transmission lines are extracted for manual monitoring, identifying overlay current and voltage frequency fault characteristics. The optimal inspection route is then determined based on these features, achieving human-machine collaboration in transmission line inspection. Experimental results demonstrate that the proposed method detected 11 fault nodes, with inspection paths closely matching the transmission line structure. It identified six defects in power system transmission lines, with an inspection time of only 2.3 seconds. The area under the ROC curve, encompassing true positive and false positive rates, is approximately 5000, indicating the method’s effectiveness, efficiency, and accuracy in inspection.
Design and research of a monitoring and environmental testing analysis system for substation status
Authors: Pang Huaying , Zhao Xi , Li Chunxiao , Pang Bo , Hang Chenhua
Published: November 2024

By testing and analyzing the real substation environment, and analyzing and fitting on-site data, a system that simulates the operating environment of the real substation is designed, and the goal of replicating a typical on-site electricity environment is achieved. Testing and analysis are conducted on the selected substation area, and light and heavy load noise is collected for spectrum analysis and measurement point attenuation analysis. The LMF (Late Multimodal Fusion) algorithm is used and test data are fitted based on the trust region theory. Conducting noise testing and attenuation analysis in the substation area has laid the foundation for research on substation status monitoring and environmental monitoring.
Research on carbon emission measurement techniques for accounting and grid auxiliary services
Authors: Wang Shuai , Wang Li , Peng Bo , Liu Yongping , Ma Weizhen
Published: November 2024

Comprehensive and accurate carbon measurement in industrial parks is an important prerequisite for grasping the current status of carbon emissions in industrial parks and exploring their carbon reduction potential. In industrial parks, a large amount of indirect or direct carbon emissions will be generated in common processes such as power use, fuel consumption, and industrial processes, and how to realize the real-time and accurate measurement of indirect and direct carbon emissions in industrial parks will become the key foundation for promoting carbon reduction and emission reduction in industrial parks. This paper focuses on the impact of auxiliary services provided by distributed power generation on carbon emissions and the integration of multi-energy carbon emission measurement technology to carry out carbon emission accurate measurement technology research, puts forward an accurate measurement method of indirect electricity carbon emission in industrial parks considering auxiliary services, and forms a carbon emission measurement technology solution in line with the new energy power generation and multiple energy use in industrial parks to provide data support for the low-carbon transformation of electric power in the parks. The study will provide data support for the low-carbon transformation of electric power and energy in the industrial park.
Non-contact fault detection of overhead insulators in distribution networks based on sound and light collaboration
Authors: Luo Busheng , Yang Wenfang , Zhong Zhenxin
Published: November 2024

Due to the low detection accuracy of traditional non-contact fault detection methods for overhead insulators in distribution networks, a non-contact fault detection method is proposed for overhead insulators in distribution networks based on sound and light collaboration. This method first uses an acoustic and optical signal acquisition device to capture insulators’ acoustic and optical signals during operation, and preprocesses the collected data to remove noise and improve signal clarity. Next, key fault features are extracted from these signals, such as the analysis of the acoustic frequency spectrum and the identification of spectral features, which help distinguish insulators’ normal working and fault states. Finally, the extracted features are classified using the support vector machine algorithm to achieve non-contact fault detection of overhead insulators in the distribution network. The experimental results show that this method can accurately and quickly detect the faults of overhead insulators in the distribution network, with high detection accuracy and practicality, providing strong technical support for the safe operation of the distribution network.
Study on the transient overvoltage suppression effect of the synchronous condenser of high percentage renewable energy in the sending-end system
Authors: Guo Qi , Li Dandan , Zhao Yue
Published: November 2024

This paper analyzes the impact of configuring a synchronous condenser on the characteristics of the Inner Mongolia power grid following the commissioning of the first grid-to-grid DC project. Simulation results show that, after the configuration of synchronous condenser, the multiple renewable energy stations short circuit ratio (MRSCR) rises, and the DC sending end of the grid is a strong system, which is conducive to the whole scale of renewable energy transmission of Inner Mongolia power grid. DC bipolar blocking faults and transient overvoltage problems at the sending end occur for different operating conditions, such as reduced power and bipolar operation. Then, the effect of different numbers of synchronous condensers on transient overvoltages is studied. The study shows that it is necessary to reasonably arrange the DC project supporting thermal power unit start-up mode and configure large-capacity synchronous condenser or a certain number of distributed regulators, which can help to alleviate the problem of transient overvoltage during faults.
Innovative heat sink design for enhanced cooling efficiency in Dual Active Bridge (DAB) topology
Authors: Liu Chenghong , Xu Zhuowei , Han Donghao , Ma Jian
Published: November 2024

After in-depth research and analysis, aiming at the heat generation mechanism and limitations of the current heat dissipation method, this paper proposes an innovative heat dissipation design scheme. By optimizing the structural design of the heat sink, the heat dissipation surface area is increased, thus achieving more efficient heat emission and maintaining the optimal operating temperature of the equipment. Experimental data show that this new heat dissipation design significantly improves the cooling efficiency, an increase of about 60%, and provides support for the performance improvement of high-power power products, which brings a reliable and efficient cooling solution for related industries.
Realization of building grade fire resistance in independent fire zone of energy storage system
Authors: Chen Man , Zhao Juran , Peng Peng , Wan Minhui , Wang Wenjie , Cao Hu , Tan Qipeng , Cong Haibo
Published: November 2024

Lithium battery energy storage technology is one of the most promising technologies in the field of energy storage. The fire prevention and control of energy storage system usually needs to consider the cooperation of various parts of the energy storage system. The domestic standard requirements for the fire resistance of energy storage system have not been completely established. In this paper, combined with the US standard and related fire resistance experimental standards, the relevant requirements and test methods for the fire insulation performance of battery cabinet of the energy storage system are studied, and a set of structural design methods and test schemes for the 2h fire resistance limit of the energy storage system are formed. The research shows that the fire insulation of the battery cabin has positive significance for reducing the energy consumption of the air conditioning of the energy storage product, improving the battery life, and enhancing the safety performance of the energy storage system. It is of great significance to study the suitable fire resistance limit of energy storage products for improving the land utilization rate of energy storage system and saving the construction cost.
A study of automatic output power control methods for stand-alone photovoltaic power generation systems
Authors: Xiao Guannan
Published: November 2024

The conventional power generation system’s output power automatic control structure is generally unidirectional, and the control coverage is small, leading to the increase in the random error obtained in the final test. Therefore, the design and research of this article are proposed. According to the current control demand, the generation system shall be stabilized first, and the power compensation shall be calculated. The multi-step mode shall be adopted to improve the control coverage and design the multi-step automatic control structure. According to this, it is constructed, and the automatic control processing is realized using jump balance. The test results show that compared with the traditional DFIG-DRWT system power output automatic control method and the traditional three-phase asynchronous generation system power output automatic control method, the random error finally obtained by the designed independent photovoltaic power station output power automatic control method is relatively effective. This indicates that the application effect and coverage of the designed power automatic control method are high, that controllability has been significantly improved, and that control flexibility has also been strengthened.
Optimization of marine hybrid power energy consumption
Authors: Song Yanlin , Zeng Xiangming
Published: November 2024

The energy and power system of the ship is the core of the ship, and the composite energy storage plays a great role in reducing the load power fluctuation of the ship, which effectively optimizes the energy efficiency index and reliability of the ship. [Objective] To better optimize the ship energy management system, a control model is established according to the characteristics of the energy system of hybrid electric ships. [Method] Energy consumption optimization is carried out by using a rule-based energy control strategy and energy control strategy based on equivalent fuel consumption minimum (ECMS). The dynamic control and strategy of the hybrid ship were optimized, and the data simulation and real ship application were carried out on the hybrid experiment platform. [Results] According to the data and results of the real ship application, the following results were shown: The daily fuel saving rate of the ECMS strategy is 14.6% in normal operating conditions and 13.3% in cruise operating conditions. [Conclusion] It has a great effect on the improvement of ship energy efficiency.
The study of active support for energy storage system in system frequency regulation
Authors: Zhou Wenchao , Liu Bing
Published: November 2024

As the penetration of new energy sources increases, the proportion of traditional energy units continues to decline, reducing the inertia and primary frequency regulation capability of the power system. Therefore, exploring the frequency support capabilities of energy storage systems with low inertia is crucial. Based on this, this paper first proposes an active frequency support method for energy storage system based on a Voltage Source Virtual Synchronous Generator (VSG), aiming to enhance system inertia and reduce response delay. Based on this issue, a parameter tuning optimization selection model based on the Transient Search Optimization (TSO) algorithm is proposed to determine the optimal power output and best frequency regulation parameters for the energy storage system. Finally, the model proposed in this paper is applied to the IEEE 14-bus system to verify its effectiveness.
Spectral bounds on the entropy flow rate and Lyapunov exponents in differentiable dynamical systems
Authors: Das Swetamber , Green Jason R
Published: November 2024

Some microscopic dynamics are also macroscopically irreversible, dissipating energy and producing entropy. For many-particle systems interacting with deterministic thermostats, the rate of thermodynamic entropy dissipated to the environment is the average rate at which phase space contracts. Here, we use this identity and the properties of a classical density matrix to derive upper and lower bounds on the entropy flow rate from the spectral properties of the local stability matrix. These bounds are an extension of more fundamental bounds on the Lyapunov exponents and phase space contraction rate of continuous-time dynamical systems. They are maximal and minimal rates of entropy production, heat transfer, and transport coefficients set by the underlying dynamics of the system and deterministic thermostat. Because these limits on the macroscopic dissipation derive from the density matrix and the local stability matrix, they are numerically computable from the molecular dynamics. As an illustration, we show that these bounds are on the electrical conductivity for a system of charged particles subject to an electric field.