bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigating the impact of black rats (Rattus rattus) on the endemic and threatened avifauna of Christmas Island
Authors: Willacy Rosalie , Flakus Samantha , McDonald-Madden Eve , Legge Sarah
Published: April 2023

Context Invasive mammalian predators are a primary cause of extinctions, especially on islands. Baseline data on the impact of invasive mammalian predators are critical for deciding whether their eradication or control should be attempted, and for monitoring ecosystem changes over time if control does occur. Christmas Island is a tropical island with multiple invasive species, including two mammalian predators (black rats, Rattus rattus and feral cats, Felis catus). Black rats are known to prey upon island bird species (including their nests) elsewhere, but the severity of their impacts on Christmas Island birds is unclear. Describing these impacts would help managers decide whether rat control is warranted, especially as a cat eradication program underway on the island could conceivably result in increased rat density. Aims In this study, we quantify the impacts of rats on Christmas Island bird abundance and nesting success. Methods The abundance of four endemic forest bird species/subspecies (Christmas Island imperial pigeon, Ducula whartoni, emerald dove, Chalcophaps indica natalis, thrush, Turdus poliocephalus erythropleurus and white-eye, Zosterops natalis) was measured using transect surveys. Nest success was measured using remote sensing camera surveillance for one forest bird species (thrush) and one seabird species (red-tailed tropicbird, Phaethon rubicaudra westralis). We explored whether these measures were related to spatial variation in rat density and activity (measured by trapping and inkcards), the presence of other invasive species, habitat and seasonal variables. Key results Neither rat density nor activity explained the abundance of any forest bird species. Instead, seasonal and habitat features were more consistent predictors of bird abundance. White-eyes were more abundant near yellow crazy ant (Anoplolepis gracilipes) supercolonies. Nest success for thrushes and red-tailed tropicbirds was either not, or only very weakly, influenced by rats. Conclusions Black rats currently have little effect on the population sizes and nesting success of Christmas Island birds. Implications This study suggests that rat control is not currently a management priority, but ongoing monitoring of rat density, activity, and impacts is needed to ensure management can respond promptly if rat density or impacts change as cat control progresses towards eradication.
Teaching Hebrew as second language in Arab schools in Israel
Authors: Manor Rama , Binhas Adi
Published: April 2023

Students belonging to the substantial Palestinian-Arab minority in Israel – about one-fifth of the population –
are required to study Hebrew as a second language (SL). This study analyzes the policy of teaching Hebrew as SL through content
analysis of policy papers, questionnaires and interviews with teachers. It aims to elicit the meaning of studying the majority
language by the minority in practical and ethnonational identity terms. The findings indicate that the current policy aims at
promoting the acquisition of spoken Hebrew for the purpose of integration in higher education and the labor market, and that
international contents are more prominent as part of the growing openness in Palestinian society in Israel. In terms of identity,
the importance of Hebrew in that society has grown, but also posed challenges in terms of the minority’s sense of belonging to
Israel and identification with the values attendant on acquiring the language. Overall, we identified interfaces between three
identity spheres: the Palestinian ethnonational identity, the Jewish-Israeli identity as encountered through Hebrew language
studies, and the global identity as represented by educational and employment opportunities and values.
Dynamic dielectric function and phonon self-energy from electrons strongly correlated with acoustic phonons in 2D Dirac crystals
Authors: Kazemian Sina , Fanchini Giovanni
Published: April 2023

The unique structure of two-dimensional (2D) Dirac crystals, with electronic bands linear in the proximity of the Brillouin-zone boundary and the Fermi energy, creates anomalous situations where small Fermi-energy perturbations critically affect the electron-related lattice properties of the system. The Fermi-surface nesting (FSN) conditions determining such effects via electron–phonon interaction require accurate estimates of the crystal’s response function

(
χ
)

as a function of the phonon wavevector q for any values of temperature, as well as realistic hypotheses on the nature of the phonons involved. Numerous analytical estimates of

χ
(

q

)

for 2D Dirac crystals beyond the Thomas–Fermi approximation have been so far carried out only in terms of dielectric response function

χ
(
q
,
ω
)

, for photon and optical-phonon perturbations, due to relative ease of incorporating a q-independent oscillation frequency

(
ω
)

in calculation. Models accounting for Dirac-electron interaction with acoustic phonons, for which ω is linear to q and is therefore dispersive, are essential to understand many critical crystal properties, including electrical and thermal transport. The lack of such models has often led to the assumption that the dielectric response function

χ
(
q
)

in these systems can be understood from free-electron behavior. Here, we show that, different from free-electron systems,

χ
(
q
)

calculated for acoustic phonons in 2D Dirac crystals using the Lindhard model, exhibits a cuspidal point at the FSN condition. Strong variability of

∂
χ

∂
q

persists also at finite temperatures, while

χ
(
q
)

tend to infinity in the dynamic case where the speed of sound is small, albeit non negligible, over the Dirac-electron Fermi velocity. The implications of our findings for electron-acoustic phonon interaction and transport properties such as the phonon line width derived from the phonon self-energy will also be discussed.
A single-turn rotating coil magnetic center calibration system designed for high energy photon source
Authors: Zhang Luyan , Han Yuanying , Dong Lan , Wang Tong , Ke Zhiyong , Wang Xiaolong , Men Lingling , Yan Luping , Lu Shang , Liu Xiaoyang , Yan Haoyue
Published: April 2023

To ensure high-precision alignment of large quantities of magnets in Chinese high energy photon source, a high magnetic center measurement efficiency is required. To achieve this, a unique single-turn rotating coil magnetic center calibration system was designed, which simplifies the traditional multi-turn compensated coil with two sets of windings that can be connected. This design reduces measurement time significantly while increasing precision by incorporating a three-coordinate measuring machine. The study presents the system’s general design, mathematical theory, and test results. Tests replacing the coil and magnets and realigning them demonstrated that the precision and measurement efficiency meet the design requirements. The displacement between the magnetic and mechanical axes was within 20 μm, indicating good performance of the well-fabricated and tested ultra-high gradient quadrupole magnet. The optimized rotating coil system design reduces the entire procedure, including magnet installation and alignment, magnetic axis measurement, and magnetic center extraction to fixed points on the magnet, to only a few hours. Several magnets participating in pre-alignment were measured, and tests and practical operation resulted in small magnetic center displacements.
Slow entropy of some combinatorial constructions
Authors: Banerjee Shilpak , Kunde Philipp , Wei Daren
Published: April 2023

Measure-theoretic slow entropy is a more refined invariant than the classical measure-theoretic entropy to characterize the complexity of dynamical systems with subexponential growth rates of distinguishable orbit types. In this paper we prove flexibility results for the values of upper and lower polynomial slow entropy of rigid transformations as well as maps admitting a good cyclic approximation. Moreover, we show that there cannot exist a general upper bound on the lower measure-theoretic slow entropy for systems of finite rank.
A novel non-contact heart rate measurement method based on EEMD combined with FastICA
Authors: Shi Yingli , Qiu Jian , Peng Li , Han Peng , Luo Kaiqing , Liu Dongmei
Published: April 2023

Objective. The imaging photoplethysmography (IPPG), which is applied to heart rate measurement, is susceptible to interference caused by illumination variations during photography. To improve the accuracy, robustness, and real-time performance of IPPG, a new method combined with modified ensemble empirical mode decomposition (EEMD) and fast independent component analysis (FastICA) was proposed. Approach. On the modified EEMD, to reduce the error caused by the residual white noise of the algorithm, it was characterized by recurrently updating zero-mean white noise for ensemble averaging based on the standard deviation of the input signal. On the modified FastICA, its constructed nonlinear function was superseded by Huber’s approximation function to improve the robustness and running speed. Main results. Comparison experiments were conducted between the MAHNOB-HCI database and own collected data. In the hybrid natural light and computer screen light scenario, the mean absolute error (MAE) of heart rate amounted to 0.93 beats per minute and the correlation coefficient

r

reached 0.85. In the experiments of MAHNOB-HCI database, the MAE amounted to 6.03 beats per minute and the correlation coefficient

r

reached 0.75. Furthermore, the modified method decreased the running time by approximately ten times compared to the original algorithms. Significance. Various experimental results demonstrated that the proposed method significantly improves the accuracy, timeliness, and interference resistance.
Model-independent radiative symmetry breaking and gravitational waves
Authors: Salvio Alberto
Published: April 2023

Models where symmetries are predominantly broken (and masses are then generated) through radiative corrections typically produce strong first-order phase transitions with a period of supercooling, when the temperature dropped by several orders of magnitude. Here it is shown that a model-independent description of these phenomena and the consequent production of potentially observable gravitational waves is possible in terms of few parameters (which are computable once the model is specified) if enough supercooling occurred. It is explicitly found how large the supercooling should be in terms of those parameters, in order for the model-independent description to be valid. It is also explained how to systematically improve the accuracy of such description by computing higher-order corrections in an expansion in powers of a small quantity, which is a function of the above-mentioned parameters. Furthermore, the corresponding gravitational wave spectrum is compared with the existing experimental results from the latest observing run of LIGO and VIRGO and the expected sensitivities of future gravitational wave experiments to find regions of the parameter space that are either ruled out or can lead to a future detection.
One-parameter dynamical dark-energy from the generalized Chaplygin gas
Authors: von Marttens Rodrigo , Barbosa Dinorah , Alcaniz Jailson
Published: April 2023

The fact that Einstein's equations connect the space-time geometry to the total matter content of the cosmic substratum, but not to individual contributions of the matter species, can be translated into a degeneracy in the cosmological dark sector. Such degeneracy makes it impossible to distinguish cases where dark energy (DE) interacts with dark matter (DM) from a dynamical non-interacting scenario using observational data based only on time or distance measurements. In this paper, based on the non-adiabatic generalized Chaplygin gas (gCg) model, we derive and study some cosmological consequences of a varying one-parameter dynamical DE parameterization, which does not allow phantom crossing.
We perform a parameter selection using the most recent publicly available data, such as the data from Planck 2018, eBOSS DR16, Pantheon and KiDS-1000. In light of this analysis, we assess how our model responds to the S
8 tension. We find that CMB data impose strong constraints on the model and conclude that the S
8 tension can be alleviated only for values of the model parameters very close to the ΛCDM cosmology.
i-SPin: an integrator for multicomponent Schrödinger-Poisson systems with self-interactions
Authors: Jain Mudit , Amin Mustafa A.
Published: April 2023

We provide an algorithm and a publicly available code to numerically evolve multicomponent Schrödinger-Poisson (SP) systems with a SO(n) symmetry, including attractive or repulsive self-interactions in addition to gravity. Focusing on the case where the SP system represents the non-relativistic limit of a massive vector field, non-gravitational self-interactions (in particular spin-spin interactions) introduce complexities related to mass and spin conservation which are not present in purely gravitational systems. We address them with an analytical solution for the `kick' step in the algorithm, where we are able to decouple the multicomponent system completely. Equipped with this analytical solution, the full field evolution is second order accurate, preserves spin and mass to machine precision, and is reversible. Our algorithm allows for an expanding universe relevant for cosmology, and the inclusion of external potentials relevant for laboratory settings.
Precision cosmology with primordial GW backgrounds in presence of astrophysical foregrounds
Authors: Racco D. , Poletti D.
Published: April 2023

The era of Gravitational-Wave (GW) astronomy will grant the detection of the astrophysical
GW background from unresolved mergers of binary black holes, and the prospect of probing the
presence of primordial GW backgrounds. In particular, the low-frequency tail of the GW spectrum
for causally-generated primordial signals (like a phase transition) offers an excellent
opportunity to measure unambiguously cosmological parameters as the equation of state of the
universe, or free-streaming particles at epochs well before recombination. We discuss whether
this programme is jeopardised by the uncertainties on the astrophysical GW foregrounds that
coexist with a primordial background. We detail the motivated assumptions under which the
astrophysical foregrounds can be assumed to be known in shape, and only uncertain in their
normalisation. In this case, the sensitivity to a primordial signal can be computed by a simple
and numerically agile procedure, where the optimal filter function subtracts the components of the
astrophysical foreground that are close in spectral shape to the signal. We show that the
degradation of the sensitivity to the signal in presence of astrophysical foregrounds is limited
to a factor of a few, and only around the frequencies where the signal is closer to the
foregrounds. Our results highlight the importance of modelling the contributions of eccentric or
intermediate-mass black hole binaries to the GW background, to consolidate the prospects to
perform precision cosmology with primordial GW backgrounds.
Firing-rate-modulated spike detection and neural decoding co-design
Authors: Zhang Zheng , Constandinou Timothy G
Published: April 2023

Objective. Translational efforts on spike-signal-based implantable brain-machine interfaces (BMIs) are increasingly aiming to minimise bandwidth while maintaining decoding performance. Developing these BMIs requires advances in neuroscience and electronic technology, as well as using low-complexity spike detection algorithms and high-performance machine learning models. While some state-of-the-art BMI systems jointly design spike detection algorithms and machine learning models, it remains unclear how the detection performance affects decoding. Approach. We propose the co-design of the neural decoder with an ultra-low complexity spike detection algorithm. The detection algorithm is designed to attain a target firing rate, which the decoder uses to modulate the input features preserving statistical invariance in long term (over several months). Main results. We demonstrate a multiplication-free fixed-point spike detection algorithm with an average detection accuracy of 97% across different noise levels on a synthetic dataset and the lowest hardware complexity among studies we have seen. By co-designing the system to incorporate statistically invariant features, we observe significantly improved long-term stability, with decoding accuracy degrading by less than 10% after 80 days of operation. Our analysis also reveals a nonlinear relationship between spike detection and decoding performance. Increasing the detection sensitivity improves decoding accuracy and long-term stability, which means the activity of more neurons is beneficial despite the detection of more noise. Reducing the spike detection sensitivity still provides acceptable decoding accuracy whilst reducing the bandwidth by at least 30%. Significance. Our findings regarding the relationship between spike detection and decoding performance can provide guidance on setting the threshold for spike detection rather than relying on training or trial-and-error. The trade-off between data bandwidth and decoding performance can be effectively managed using appropriate spike detection settings. We demonstrate improved decoding performance by maintaining statistical invariance of input features. We believe this approach can motivate further research focused on improving decoding performance through the manipulation of data itself (based on a hypothesis) rather than using more complex decoding models.
Two-dimensional diffusive epidemic process in the presence of quasiperiodic and quenched disorder
Authors: Alencar D S M , Alves T F A , Alves G A , Lima F W S , Macedo-Filho A , Ferreira R S
Published: April 2023

This work considers the diffusive epidemic process model coupled to the square lattice, the Penrose quasiperiodic lattice, and the Voronoi–Delaunay random lattice. The main objective is to verify if spatial disorder influences critical behavior. According to the Harris–Barghathi–Vojta criterion, quenched or quasiperiodic disorder can change the critical behavior of the system, depending on the disorder decay exponent of the lattice. We employed extensive Monte Carlo simulations of the relevant quantities. Furthermore, we estimate the critical exponent ratios. Our results suggest that the disorder does not change the critical behavior when comparing the critical exponent ratios for the three studied lattice structures. In addition, the critical exponents depend on the three possible diffusion regimes: (1) where diffusion is dominated by susceptible individuals, (2) where infected and susceptible individuals have the same diffusion constant, and (3) where diffusion is dominated by the infected individuals.
New duality relation for the discrete Gaussian SOS model on a torus
Authors: Cornu F , Hilhorst H J , Bauer M
Published: April 2023

We construct a new duality for two-dimensional discrete Gaussian models. It is based on a known one-dimensional duality and on a mapping, implied by the Chinese remainder theorem, between the sites of an N × M torus and those of a ring of NM sites. The duality holds for an arbitrary translation-invariant interaction potential

v
(

r

)

between the height variables on the torus. It leads to pairs

(
v
,

v
˜

)

of mutually dual potentials and to a temperature inversion according to

β
˜

=

π
2

/

β

. When

v
(

r

)

is isotropic, duality renders an anisotropic

v
˜

. This is the case, in particular, for the potential that is dual to an isotropic nearest-neighbor potential. In the thermodynamic limit, this dual potential is shown to decay with distance according to an inverse square law with a quadrupolar angular dependence. There is a single pair of self-dual potentials

v
⋆

=

v
⋆

˜

. At the self-dual temperature

β
⋆

=

β
⋆

˜

=
π

the height–height correlation can be calculated explicitly; it is anisotropic and diverges logarithmically with distance.
A magnetoelectric heterostructure employing a magnetic levitation mechanism for harvesting low-frequency vibration energy
Authors: He Wei , Liu Shuanghua
Published: April 2023

A magnetoelectric (ME) heterostructure using shear-mode ME transducers to extract ambient low-frequency vibration energy is proposed. The demand for the traditional mechanical spring is eliminated by utilizing a magnetic levitation mechanism. When the suspending magnet moves relative to the ME transducers, the piezoelectric plates deform in shear mode owing to the magnetostriction of the magnetostrictive plates, and large shear piezoelectric effect is induced. Consequently, larger voltages can be produced by the presented device. The kinetic equation of the energy harvesting system is derived and solved, and the maximum output power is obtained based on the vibration rule and the variation of the sensed magnetic field. The feasibility of the heterostructure is experimentally verified. The maximum load power increases with acceleration. A maximum output power of 1.46mW is generated across a 1.25MΩ resistive load at the acceleration of 0.7g. The generated energy of the heterostructure is sufficient to drive a low-power electronic device. Improvements are feasible, which allow an obvious increase of the maximum output powers by employing a Halbach array with a particular arrangement of the magnets.
Analysis of Dynamic Operation Characteristics of the Integrated Energy System
Authors: Zhai Jiang , Yang Jing , Dang Yanyang , Wang Xiang , Zhang xingliang
Published: April 2023

Gas turbines make the coupling between the natural gas system(NGS) and the power system tighter. So Natural gas systems and power systems are interdependent in security and stability, and only paying attention to the security of the power system itself can not guarantee the security and stability of the system. To meet the problem and challenge, in this paper, a technical route based on the method of characteristic (MOC) is proposed to analyze the interaction of integrated energy systems (IES). It can calculate the transient process of the active and reactive power output of GT after the fluctuation of the NGS. Then, according to the dynamic math model of the natural gas in the pipeline(line-pack), the dynamic change of the line-pack is calculated, and the maximum interruption time of the gas source can be calculated according to the line-pack calculation result. Because of the intrinsic mechanism advantages of the MOC, the time step in the simulation calculation can be very small, which does not affect the calculation efficiency. It can calculate the dynamic change of GT output power, identify weak links in the operation of the system, and provide an important decision-making basis for taking safety control measures. Finally, based on an IES case, it is verified that the method proposed in this paper is of great value to analyze the security and stability of the IES.
Research on the application and benefit of energy storage technology
Authors: Sun Xiaoguang , Geng Jianyu , Liu Kai , Wang Yuanzhi , Wang Zhipeng
Published: April 2023

The randomness, volatility and un-dispatch ability of large-scale new energy connected to the grid have caused a series of problems with the stable operation of the grid and great difficulties with power dispatch. The configuration of the energy storage power station and substation is studied through the metering and reliable capacity planning method of energy storage power station and substation capacity planning. This will improve the level of utilization of grid assets and promote the coordinated development of new energy, energy storage and the grid.
Optimization of Ultrasonic Welding Parameters Based on Response Surface Methodology
Authors: Yao Zhen , Liu Kaijie , Ding Rongjie , Luo Zilun , He Jian
Published: April 2023

In this paper, the optimal process parameters for ultrasonic welding of copper wire and aluminum plates are studied using the response surface method. The effect of various welding parameters on the welding effect is experimentally tested. The results are analyzed using the Box-Behnken design to establish a regression model to optimize the welding parameters. The model uses the welding height, welding energy and welding pressure as influencing factors and the welding strength and welding time as response values. The results show that optimal welding of copper wire and aluminum plate is obtained at the height of 2.2mm, energy 1300J, amplitude 85% or 95%. The response surface method used in this paper can provide a reference for the ultrasonic welding of other materials in the study of process parameters.
Gate modulation drive and modeling of IGBT in MMC converters
Authors: Wang Kefeng , Wen Fuyue , Sun Baokui , Zhou Jianbo , Han Lei , Wang Jiangyong
Published: April 2023

The energy surplus caused by the alternating current (AC) system’s failure results in a severe overvoltage problem in Bai hetan-Jiangsu ±800 kV hybrid cascade direct current (DC) project. However, the insulated gate bipolar transistor’s (IGBT) off-state voltage is the crucial reason for the insufficient voltage capacity of modular multilevel converter (MMC). Therefore, analysis and suppression of the off-state overvoltage are of vital significance. The off-state model of IGBT in an MMC converter is established, and the process of IGBT’s turning off is analyzed. Then, based on the characteristics of IGBT’s off-state and traditional resistance switching strategy, the gate modulation drive strategy is proposed, and the equivalent topology of the MMC submodule with the strategy is established. Finally, MMC submodule models with gate modulation drive and resistance switching strategy, respectively, are built in simulation software, and two groups of data are compared under multiple groups of the control cycle and reference current slope given. The simulation results show that the gate modulation drive supresses the off-state overvoltage on IGBT better than the resistance switching strategy. Moreover, the shorter the control cycle and the less reference current slope, the better the overvoltage suppression.
Comparison of Power Density of Triboelectric Generators via Frequency-up-Conversion Method
Authors: Li Zhongjie , Yang Chao , Peng Yan , Shen Fan , Peng Xuzhang
Published: April 2023

In this paper, we experimentally compared the instantaneous volume power density and the average volume power density of the triboelectric nanogenerator (TENG) with and without a frequency-up conversion mechanism. We first proposed a double-cantilever structure TENG (DC-TENG). A conventional contact-separation TENG was also constructed as the control case for electric output comparison. A few experiments were then conducted to investigate how the cantilever’s high-frequency vibrations influence the output voltage, instantaneous power, etc., before those of the triboelectric nanogenerator without frequency conversion. The results indicate that the double-cantilever system effectively converts low-frequency linear impact into high-frequency vibration. As of the best contrast, the DC-TENG yields a maximal open-circuit voltage of 141.5 V, an instantaneous power of 0.76 mW, and an average power of 0.77 μW excited by a linear impact, which frequency is 0.6 Hz and amplitude is 8 mm. The peak and the average power density of generators with the frequency convert device are enhanced by 34 times and 13 times as high as those of the original case, respectively. This finding proves that the cantilever integrated with triboelectric nanogenerators is an effective configuration with evident performance improvement.
Study on the application of photovoltaic power generation systems in field observatories under the zero carbon goal
Authors: Yao Jianan , Niu Junkui , Wang Binbin , Li Wenbing , Chen Long
Published: April 2023

Emissions of greenhouse gases such as CO2 are rapidly increasing, causing the greenhouse effect, leading to global warming and serious impacts on the ecosystem, while photovoltaic power generation can reduce the large amount of pollutants and carbon emissions produced in the traditional power generation process. The article takes the photovoltaic power generation system of the national field observatory as the research object, and uses PVsyst software to design the system of two distributed photovoltaic power generation systems. After calculating and analysing the total power of the experimental equipment, the efficiency of photovoltaic power generation and the system cost of the field observatory, the scheme and scale of the photovoltaic power generation system are determined, and the construction of the photovoltaic power generation test system is completed. Finally, through the comparison and analysis of the one-year PV power generation data with the simulated data, the feasibility of the system design method is verified, which can meet the requirements of the field experimental station and create a zero-carbon field observatory to achieve green energy conservation and sustainable energy use, which is in line with the strategic development plan of carbon peaking and carbon neutrality promoted by the state and provides a design basis and useful reference for the construction of zero-carbon field experimental stations.
Study on the Characteristics, Harm, Mechanism and Prevention Measures of Corrosion at the Tower Foot of Transmission Line
Authors: Li Yufeng , Wu Peicheng , Chen Haideng , Tao Xianghai , Gao Tianshu , Chen Honglin
Published: April 2023

The transmission line is the key medium and channel for power transmission from the power supply side to the power consumption side. As the infrastructure supporting the transmission line, the iron tower is crucial for the safe and stable operation of the grid. In recent years, the phenomenon of corrosion at the foot of power transmission towers has been expanding, which is a major hidden danger affecting the security of the power grid. Based on the actual situation, this paper summarizes the corrosion characteristics of the current transmission line tower foot and points out the harm and reaction mechanism of tower foot corrosion. According to the existing technical conditions, the corrosion prevention measures for the tower foot are proposed to eliminate the hidden danger of tower corrosion from the root and improve the safe operation level of transmission lines, which can be used for reference by relevant personnel.
Research on Sensorless Control of Permanent Magnet Synchronous Motor Based on Novel Sliding Mode Observer
Authors: Qi Ge , Hu Wanlong , Ma Ding , Huang Wenhao
Published: April 2023

In this paper, an improved SMO system is proposed to solve the problems of jitter and poor interference immunity of the conventional SMO system, the system is improved by replacing and adding three new simulation modules. Starting from the ideas of the “quasi-sliding module” and “boundary layer” of sliding mode control theory, by replacing the symbolic function in the conventional observer with an exponential segmentation function, which can effectively suppress the jitter phenomenon. And for different speed motor control application scenarios, a variable sliding mode gain coefficient that can be dynamically changed with the motor speed is used. For the system’s anti-jitter performance to be improved, a variable sliding mode gain coefficient that can be dynamically changed with the motor speed is introduced, which has stronger self-adaptability in different speed scenarios. An improved SMO system is formed by adding three new and improved modules, and this basis is tested experimentally on the MATLAB/Simulink simulation platform. The SMO with the addition of three new modules can be tested by simulation experiments to know that it has stronger anti-disturbance and self-adaptive capabilities under change scenarios such as sudden changes in load torque and sudden changes in speed.
The Method of Photovoltaic Power Forecast based on Seasonal Classification and Limit Learning Machine
Authors: Li Dengxuan , Ma Wenwen , Hu Siyu , Qin Fang , Chen Weidong , Ding Huang , Han Yutong
Published: April 2023

The seasonal distribution characteristics of photovoltaic power plant output fluctuation are analyzed, and a short-term power forecasting method based on seasonal classification is proposed. Firstly, the seasonal distribution characteristics of photovoltaic output and its fluctuation are analyzed. Secondly, the forecasting model of photovoltaic output in different seasons is established by the Limit Learning Machine neural network. Finally, an empirical analysis is carried out by using photovoltaic output data. The results show that the seasonal classification method of short-term PV power forecast is better than the unclassified model.
Design of voltage stabilizing control for a hybrid microgrid with state constraints based on the switching system
Authors: Wang Zonghao , Sun Liying
Published: April 2023

With the application and development of new energy generation technology and distributed power supply system, AC-DC hybrid microgrid has the comprehensive advantages of AC microgrid and DC microgrid, and it is significant to study the voltage stability of hybrid microgrid. Based on the switching system theory, the voltage stability control of the ac-dc hybrid micro-grid in grid-connected and the off-grid operation mode are studied in this paper. Considering that the AC and DC bus voltages of the microgrid are constrained in practical engineering applications, the Backstepping controller is designed by using the barrier Lyapunov function and Backstepping method. Considering that the equivalent resistance in the system can not be accurately measured and combined with adaptive control, it is more practical for practical engineering applications.
Simulation study on disturbance of energy storage microgrid system based on bi-directional DC/DC converter
Authors: Yu Di , Fu Liyou
Published: April 2023

With the national policy of energy saving and emission reduction, microgrid technology has gradually entered into people’s daily life and received more and more technical and financial support. In this paper, we build an energy storage microgrid system based on a bi-directional DC/DC converter through Matlab/Simulink software, construct a simple simulation model of a PV battery, storage battery and bi-directional DC/DC converter, and simulate and verify the anti-interference ability and stability recovery ability of the microgrid under the situation of external disturbance. The experimental results show that the system can simulate the operation of a microgrid system.
Hidden Markov Chain Model-Based Intelligent Distributed Optimization Scheduling Operation Error Prevention Method for Main Network
Authors: Yang Sheng , Liu Jinming , Zhou Zhicheng , Ning Yangtian
Published: April 2023

After the implementation of the intelligent distributed optimal dispatching mode of the main network, the number of operations is more frequent, resulting in the problem of operation error, which affects the reliability and stability of the power grid operation. In this paper, a hidden Markov chain (HMC) model-based intelligent distributed optimization scheduling operation error prevention method for the main network is proposed. In this study, the power grid topology model is established through continuous access, which lays the foundation for the dynamic tracking of dispatching operation instructions. The hidden Markov chain model is used to estimate the operational risk of scheduling. Combining with the association mining theory, the anti-error detection rules between risk and anti-error strategy are established, and the anti-error strategy is implemented. The results show that under the application of the operation error prevention method, the operation error prevention response time difference and the voltage fluctuation range of the power grid reach the minimum. Through this study, it is expected to provide a reliable reference for dispatchers to make more effective dispatching decisions and correct dispatching errors in time.
Analysis of the voltage impact on the distribution network after PV connection and its reactive power optimization
Authors: Jiang Zhongwei
Published: April 2023

Under the context of building a new type of power system, distributed PV is connected to the distribution network on a large scale, further increasing the penetration rate of the distribution network. The access of distributed PV causes many problems, such as voltage rise at distribution network nodes and transformer power back feeding. This paper first analyses the impact of PV connection at different locations in the distribution on the node voltage of the distribution network. The Grey Wolf Algorithm (GWA) is then applied to optimize the nodal voltage and branch network losses for the rational allocation of PV capacity and access to shunt compensation capacitors. Finally, the method’s effectiveness is verified using the IEEE33 bus system.
Consider the optimal allocation planning of energy storage for flexible resources of source network load
Authors: Chen Hao , Liu Zhaoyang , Wang Binbin , Liang Yan , Wang Yongli , Guo Wenhui , Lu Yuhan
Published: April 2023

The increased penetration of distributed generation such as wind and light in the distribution grid causes dramatic fluctuations in net load, resulting in a sharp increase in the need for distribution grid flexibility. To this end, a distribution grid energy storage optimal allocation method considering source-net-load flexibility resources is proposed. First, a set of uncertain operation scenarios is established from multiple time scales using the K-means method and robust optimization theory; second, an economically flexible multi-objective optimization model with the minimum annual integrated cost and the highest average daily flexibility level of the distribution network as the optimization objectives is established and solved by a multi-objective composite differential evolutionary algorithm with embedded tide calculation. Arithmetic design and simulation are based on the IEEE 33-node distribution network system. The results validate the reasonableness and effectiveness of the proposed model considering source-grid-load flexibility resources in solving the energy storage allocation scheme.
Fault Prediction Method of Intelligent Distribution Switchgear Based on Nearest Neighbor-Gradient Hybrid Learning-RBF Neural Network for State Aware
Authors: Sun LingChen , Yu Yue , Yuan Yi , Qi Peng , Liu ZhenYu , Wu YiXuan , Kong LingYu
Published: April 2023

For ensuring the safe operation of distribution switch cabinet, a regular maintenance system is implemented. As the specific conditions of the equipment operation are not considered, there are too many unnecessary shutdowns and maintenance, resulting in the situation that “the equipment is not damaged, but repaired”. Moreover, troubleshooting mainly depends on the sense organs, experience and instruments of the maintenance personnel. The ability and experience of the maintenance staff is what limits the quality of the maintenance since the time spent identifying the fault reasons typically makes up more than 60% of the overall troubleshooting time. The stability of the entire power supply system is directly impacted by the dependability and safety of the power distribution switchgear. To prevent “insufficient maintenance” and “excessive maintenance” brought on by planned maintenance. This paper examines the RBF neural network’s offline and online training techniques as a result. Additionally, the analysis of the RBF neural network’s offline and online training techniques is proposed using the closest neighbor-gradient hybrid learning algorithm. Additionally, the hybrid closest neighbor-gradient training approach is suggested. Experiments using Matlab simulations show that the diagnostic results are more accurate.
Radiation studies performed on the High Luminosity ATLAS TileCal link Daughterboard
Authors: Valdes Santurio E. , Silverstein S. , Bohm C. , Motzkau H. , Clement C. , Dunne K. , Lee S.
Published: April 2023

The new electronics of the ATLAS Tile Calorimeter for the HL-LHC interfaces the on-detector and off-detector electronics by means of a Daughterboard. The Daughterboard is positioned on-detector featuring commercial SFPs+, CERN GBTx ASICs, ProASIC FPGAs and Kintex Ultrascale FPGAs. The design minimizes single points of failure and mitigates radiation damage by means of a double redundant scheme, Triple Mode Redundancy, Xilinx Soft Error Mitigation IP, CRC/FEC for link data transfer, and SEL protection circuitry. We present an updated summary of the TID, NIEL and SEE qualification tests, and performance studies of the Daughterboard revision 6 design.
Influence of seasonal climatic water deficit and crop prices on rainfed crop grain harvest, repurposing, and abandonment in the western U.S.A.
Authors: Lauffenburger Zachary H , Maneta Marco P , Miller Perry , Kimball John S
Published: April 2023

Increasing climate aridity and drought, exacerbated by global warming, are increasing risks for western United States of America (U.S.A.) rainfed farming, and challenging producers’ capacity to maintain production and profitability. With agricultural water demand in the region exceeding limited supplies and fewer opportunities to develop new water sources, rainfed agriculture is under increasing pressure to meet the nation’s growing food demands. This study examines three major western U.S.A. rainfed crops: barley, spring wheat, and winter wheat. We analyzed the relationship between crop repurposing (the ratio of acres harvested for grain to the total planted acres) to seasonal climatic water deficit (CWD). To isolate the climate signal from economic factors, our analysis accounted for the influence of crop prices on grain harvest. We used historical climate and agricultural data between 1958 and 2020 to model crop repurposing (e.g. forage) across the observed CWD record using a fixed effect model. Our methodology is applicable for any region and incorporates regional differences in farming and economic drivers. Our results indicate that farmers are less likely to harvest barley and spring wheat for grain when the spring CWD is above average. Of the major winter wheat growing regions, only the Northern High Plains in Texas showed a trend of decreasing grain harvest during high CWD. For the majority of major crop growing regions, grain prices increased with lower levels of grain harvest. Interestingly, winter wheat repurposing is significantly higher in the southern Great Plains (∼50% harvested for grain) compared to the rest of the West (∼90%). Our results highlight that the major barley and spring wheat regions’ grain harvests are vulnerable to high spring CWD and low summer CWD, while winter wheat grain harvest is unaffected by variable CWD in most of the West.
Poisson points, resetting, universality and the role of the last item
Authors: Godrèche Claude
Published: April 2023

For a stochastic process reset at random times, we discuss to what extent the probabilities of some orderings of observables associated with the intervals of time between resetting events are universal, i.e. independent of the choice of the observables, and in particular, to what extent universality depends on the choice of the distribution of these intervals. For Poissonian resetting, universality relies only on a combinatorial argument and on the statistical properties of Poisson points. For a generic distribution of time intervals between resets, universality no longer holds in general.
Green Synthesis Optimization and Characterization of Selenium Nanoparticle Using Aqueous Extract of Peel Solanum Melongena L.
Authors: Ali Ban Mohammed Hussein , Almashhedy Lamia A. M.
Published: April 2023

Recently, employing vegetable peel waste in green biosynthetic methods has received increased attention. It has low toxicity levels, is safe for the environment, and is simple to produce. The purpose of this research was to develop a sustainable technique of synthesizing SeNPs from an aqueous extract of eggplant peel. Because of this, selenium nanoparticles were produced in a single step utilizing an aqueous extract of peel Solanum melongena L. as a reducing and capping agent. The nanoparticles, which were studied using UV-Vis spectroscopy, had a surface Plasmon resonance centered at 320 nm. Nanoparticles sized between 50 and 150 nm were observed using a scanning electron microscope, while X-ray diffraction patterns revealed their amorphous, face-centered structure. Current research looks into how optimizing factors like reaction time, temperature, pH, selenous acid concentration, and reactant mixing ratio affect the quality of produced selenium nanoparticles. We found that 30 mM selenous acid, 30 degrees Celsius, pH 4, 9 days of incubation, and a 2:10 ratio of aqueous extract to selenous acid produced the highest quality selenium nanoparticles.
Determination of the Efficacy of Broccoli Sprouts Seeds on Growth, Blood Parameters, and Immunological Indicators in Experimentally Immunosuppressed Male Rats
Authors: Al-Qaraghli Adnan Nsaif Hammadi , Ayed Hani Sabbar
Published: April 2023

This study was conducted in graduate laboratories, College of Agriculture, University of Baghdad’s and animal house in College of Veterinary Medicine, University of Tikrit to determine the effectiveness of broccoli sprouted seeds on growth parameters, blood components and measurement of immune indicators in male rats with experimentally reduced immunity. The results of the study showed that oral administration of Sandimmun to male albino rats led to a decrease in the weight gain rate of laboratory rats and a decrease in blood components such as the white blood cell count (WBC), red blood cell count (RBC) and hemoglobin concentration level (Hb), while there was a significant increase in the number of platelets (PLT). It also caused a significant decrease in the values of the immunological indicators like IgG, IgA, and IgM. The results showed that feeding on broccoli sprouted seed powder with both concentrations 15% and 30% caused an increase in the weight gain rates to 53.40 and 84.40 g, respectively, compared to the average weights gained for the rats with reduced immunity in treatment G2, which was 15.40 g. The same applies to the effect of feeding on the two treatments G3 and G4. These groups had significant improvement in the blood parameters of rats in both treatments, but the G4 treatment was the best treatment in raising the level of white blood cell counts WBC, which amounted to 14.90x109 cell/ml while the number of RBC erythrocytes was at 8.18x106 cell/ml compared with their numbers in the experimentally immunocompromised group of rats, which were at 15.12x109 cell/ml and 8.06 x106 cells/ml, respectively. While the concentration of hemoglobin (Hb) level was at 13.68 mg/dL, the number of Platelets (PLT) 485x103 platelets / microliter and all these values were significantly similar with their numbers in the values of treatment G1. Also, feeding at a concentrations of 15% and 30% led to increase the immunoglobulins IgG, IgA and IgM in rats, as it caused an increase in their values in treatment G3, which were at 0.48, 0.44, 0.52 mg/dL, respectively. While their values in treatment G4 were at 0.54, 0.47, and 0.56 mg/dL, compared with their values in treatment G2, which amounted to 0.35, 0.33, 0.41 mg/dL. The conclusion of this study is that feeding with broccoli sprouted seed powder improved the growth rates, blood profile parameters and immune globulins in the experimentally reduced immune male rats.