bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact of anti-solar differential rotation in mean-field solar-type dynamos
Authors: Noraz Q. , Brun A. S. , Strugarek A. , Depambour G.
Published: November 2021

Context.Over the course of their lifetimes, the rotation of solar-type stars goes through different phases. Once they reach the zero-age main sequence, their global rotation rate decreases during the main sequence until at least the solar age, approximately following the empirical Skumanich’s law and enabling gyrochronology. Older solar-type stars might then reach a point of transition when they stop braking, according to recent results of asteroseismology. Additionally, recent 3D numerical simulations of solar-type stars show that different regimes of differential rotation can be characterized with the Rossby number. In particular, anti-solar differential rotation (fast poles, slow equator) may exist for high Rossby number (slow rotators). If this regime occurs during the main sequence and, in general, for slow rotators, we may consider how magnetic generation through the dynamo process might be impacted. In particular, we consider whether slowly rotating stars are indeed subject to magnetic cycles.

Aims.We aim to understand the magnetic field generation of solar-type stars possessing an anti-solar differential rotation and we focus on the possible existence of magnetic cycles in such stars.

Methods.We modeled mean-field kinematic dynamos in solar (fast equator, slow poles) and anti-solar (slow equator, fast poles) differential rotation, using the STELEM code. We consider two types of mean field dynamo mechanisms along with the Ω-effect: the standardα-effect distributed at various locations in the convective envelope and the Babcock-Leighton effect.

Results.We find that kinematicαΩ dynamos allow for the presence of magnetic cycles and global polarity reversals for both rotation regimes, but only if theα-effect is saddled on the tachocline. If it is distributed in the convection zone, solar-type cases still possess a cycle and anti-solar cases do not. Conversely, we have not found any possibility for sustaining a magnetic cycle with the traditional Babcock-Leighton flux-transport dynamos in the anti-solar differential rotation regime due to flux addition. Graphic interpretations are proposed in order to illustrate these cases. However, we find that hybrid models containing both prescriptions can still sustain local polarity reversals at some latitudes.

Conclusions.We conclude that stars in the anti-solar differential rotation regime can sustain magnetic cycles only for very specific dynamo processes. The detection of a magnetic cycle for such a star would therefore be a particularly interesting constraint in working to decipher what type of dynamo is actually at work in solar-type stars.
Approach to the Patient with Gait Disturbance
Authors: Tarolli Christopher G. , Lizarraga Karlo J.
Published: November 2021

The assessment of patients presenting with disorders of gait can be a daunting task for neurologists given the broad potential localization and differential diagnosis. However, gait disorders are extremely common in outpatient neurology, and all neurologists should be comfortable with the assessment, triage, and management of patients presenting with difficulty walking. Here, we aim to present a manageable framework for neurologists to approach the assessment of patients presenting with gait dysfunction. We suggest a chief complaint-based phenomenological characterization of gait, using components of the neurological history and examination to guide testing and treatment. We present the framework to mirror the outpatient visit with the patient, highlighting (1) important features of the gait history, including the most common gait-related chief complaints and common secondary (medical) causes of gait dysfunction; (2) gait physiology and a systematic approach to the gait examination allowing appropriate characterization of gait phenomenology; (3) an algorithmic approach to ancillary testing for patients with gait dysfunction based on historical and examination features; and (4) definitive and supportive therapies for the management of patients presenting with common neurological disorders of gait.
Approach to Common Visual Complaints Presenting to the Outpatient Neurologist
Authors: Greer Christine , Dinkin Marc
Published: November 2021

Visual complaints are commonly encountered by the practicing neurologist. We review assessment of vision loss, diplopia, and positive visual phenomena, all of which require a thoughtful evaluation to localize disease and refine management. While many causative entities are unlikely to cause poor visual outcomes, including dry eyes, migraine, and congenital strabismus, others may threaten vision, life, or both, such as posterior communicating artery aneurysms, pituitary apoplexy, or temporal arteritis. A systematic approach to vision loss and diplopia is reviewed along with focused differential diagnoses.
Relative performance of white clover (
Authors: Jahufer M. Z. Z. , Ford J. L. , Cousins G. R. , Woodfield D. R.
Published: November 2021

Assessment of the relative performance of white clover (Trifolium repens L.) cultivars, using multi-year and multi-location seasonal growth trials, is key to identification of material with specific and broad adaptation. This paper is based on a multi-year and multi-location study of 56 white clover entries comprising 14 commercial cultivars and 42 experimental synthetic lines evaluated for seasonal growth under rotational grazing across four locations in New Zealand over 4 years. The four locations (and animals grazing) were: Kerikeri (beef cattle), Aorangi (beef cattle), Ruakura (dairy cattle), Lincoln (sheep). Significant (P < 0.05) genotypic variation among the 56 entries, and genotype × year, genotype × location and genotype × season interactions, were estimated. We were able to identify cultivars and experimental synthetics with specific and broad adaptation to the three grazing management types. Cvv. AberDance, Apex, Demand, Prestige, Quartz and Riesling, with leaf size ranging from small to medium–large, showed highly above-average performance under sheep grazing. Synthetic lines 15 and 45 also had highly above-average performance under sheep grazing. Cvv. Legacy and Kopu II showed above-average performance under cattle and dairy grazing. Synthetics 15, 48, 49, 44, 22 and 18 and cv. Quartz had above-average performance under all three grazing managements. Synthetics 27, 33 and 38 had highly above-average performance across all three grazing managements and were superior to all 14 cultivars evaluated. Several of these superior synthetics are being tested across multiple grazing environments. Among the 14 cultivars evaluated, Legacy and Quartz showed superior seasonal growth performance across the three grazing managements. Quartz is being evaluated in several on-farm trials across temperate regions of the world.
Does the carbon skeleton of biochar contribute to soil phosphate sorption? A case study from paddy soils with woody biochar amendment
Authors: Qin Guobing , Yan Xiao , Wei Jinju , Wu Jianfu , Wei Zongqiang
Published: November 2021

Context The phosphorus (P) sorption capacity of biochar and the effects of biochar amendment on soil P sorption and availability remain uncertain. Aims This study determined the specific contributions of the biochar inorganic component (mineral ash) and its carbon skeleton to the P sorption capacity of biochar. Methods A woody biochar and its acid-washed counterpart were added to two types of paddy soils with two P-retention capacities: high P sorption (HPS) and low P sorption (LPS). Key results Washing biochar with HCl solution drastically decreased the concentrations of calcium, magnesium, iron (Fe), and aluminium (Al) in the biochar. However, Fourier transform infrared and X-ray photoelectron spectroscopy spectra indicated that the washing procedure did not decrease the biochar organic carbon content and its surface functional groups. Acid-washed biochar showed nearly zero P sorption after 24 h of equilibration with P solution, and its incorporation had little effect on P sorption of the two paddy soils. Amendment with original alkaline woody biochar tended to increase P sorption capacity of LPS soils, but decreased that of HPS soils. The variations in Langmuir P sorption maxima, an indicator of soil P sorption capacity, among the soils and biochar treatments could be primarily explained by the amorphous Fe and Al concentrations, which indicates that the effect of biochar addition on soil P sorption was highly dependent on intrinsic soil P-retentive properties. Conclusion These results demonstrate that the biochar carbon skeleton had a very limited contribution to biochar P-retention capacity. Implications Our results suggest that the application of aged biochar with lower mineral contents to humid acidic highly weathered soils will have limited P retention capacity.
Generating a dynamical M2 brane from super-gravitons in a pp-wave background
Authors: Chen Yi-Fei , Lu J X , Zhang Nan
Published: November 2021

We present a detailed study of dynamically generating an M2 brane from super-gravitons (or D0 branes) in a pp-wave background possessing maximal spacetime SUSY. We have three kinds of dynamical solutions depending on the excess energy which appears as an order parameter signalling a critical phenomenon about the solutions. As the excess energy is below a critical value, we have two branches of the solution, one can have its size zero while the other cannot for each given excess energy. However there can be an instanton tunnelling between the two. Once the excess energy is above the critical value, we have a single solution whose dynamical behavior is basically independent of the background chosen and whose size can be zero at some instant. A by product of this study is that the size of particles or extended objects can grow once there is a non-zero excess energy even without the presence of a background flux, therefore lending support to the spacetime uncertainty principle.
Correlation and trust mechanism-based rumor propagation model in complex social networks
Authors: Sun Xian-Li , Wang You-Guo , Cang Lin-Qing
Published: November 2021

In real life, the rumor propagation is influenced by many factors. The complexity and uncertainty of human psychology make the diffusion model more challenging to depict. In order to establish a comprehensive propagation model, in this paper, we take some psychological factors into consideration to mirror rumor propagation. Firstly, we use the Ridenour model to combine the trust mechanism with the correlation mechanism and propose a modified rumor propagation model. Secondly, the mean-field equations which describe the dynamics of the modified SIR model on homogenous and heterogeneous networks are derived. Thirdly, a steady-state analysis is conducted for the spreading threshold and the final rumor size. Fourthly, we investigate rumor immunization strategies and obtain immunization thresholds. Next, simulations on different networks are carried out to verify the theoretical results and the effectiveness of the immunization strategies. The results indicate that the utilization of trust and correlation mechanisms leads to a larger final rumor size and a smaller terminal time. Moreover, different immunization strategies have disparate effectiveness in rumor propagation.
MIX Reality Based Media Prototype For Learning Physics of Gravity And Kepler’s Law
Authors: Munawaroh L W , Serevina V , Iswanto B H
Published: November 2021

Gravity and Kepler’s Laws are materials that study natural phenomena, events or phenomena that reveal all the secrets of the universe. Based on the observations of several schools, there are difficulties for students understanding gravity and Kepler’s laws because they can not directly present 3D learning media in interactive classes. This study aims to develop a mixed reality-based media prototype for learning gravity physics and Kepler’s laws using special VR box glasses and markers to display 3D objects equipped with audio explanations, 3D animations, and evaluation questions. The research was conducted using the ADDIE development model (Analyze, design, develop, implement, and evaluate). To make it easier for students to use mix reality applications, the mix reality software design employs blender version 2.78, unity 5.1, Photoshop, the vuforia AR extension for unity, and the c # programming language. The trial of the feasibility of mix reality media was conducted by averaging the results of the validator’s assessment of each aspect of the assessment. Mixed reality media prototypes can help students understand gravity and Kepler’s laws.
PT

-symmetric classical mechanics
Authors: Bender Carl M , Hook Daniel W
Published: November 2021

This paper reports the results of an ongoing in-depth analysis of the classical trajectories of the class of non-Hermitian

PT

-symmetric Hamiltonians H = p2 + x2
(ix)
ε
(ε ⩾ 0). A variety of phenomena, heretofore overlooked, have been discovered such as the existence of infinitely many separatrix trajectories, sequences of critical initial values associated with limiting classical orbits, regions of broken

PT

-symmetric classical trajectories, and a remarkable topological transition at ε = 2. This investigation is a work in progress and it is not complete; many features of complex trajectories are still under study.
An introductory review on resource theories of generalized nonclassical light
Authors: Dey Sanjib
Published: November 2021

Quantum resource theory is perhaps the most revolutionary framework that quantum physics has ever experienced. It plays vigorous roles in unifying the quantification methods of a requisite quantum effect as wells as in identifying protocols that optimize its usefulness in a given application in areas ranging from quantum information to computation. Moreover, the resource theories have transmuted radical quantum phenomena like coherence, nonclassicality and entanglement from being just intriguing to being helpful in executing realistic thoughts. A general quantum resource theoretical framework relies on the method of categorization of all possible quantum states into two sets, namely, the free set and the resource set. Associated with the set of free states there is a number of free quantum operations emerging from the natural constraints attributed to the corresponding physical system. Then, the task of quantum resource theory is to discover possible aspects arising from the restricted set of operations as resources. Along with the rapid growth of various resource theories corresponding to standard harmonic oscillator quantum optical states, significant advancement has been expedited along the same direction for generalized quantum optical states. Generalized quantum optical framework strives to bring in several prosperous contemporary ideas including nonlinearity,

PT

-symmetric non-Hermitian theories, q-deformed bosonic systems, etc., to accomplish similar but elevated objectives of the standard quantum optics and information theories. In this article, we review the developments of nonclassical resource theories of different generalized quantum optical states and their usefulness in the context of quantum information theories.
Antilinear symmetry and the ghost problem in quantum field theory
Authors: Mannheim Philip D.
Published: November 2021

The recognition that the eigenvalues of a non-Hermitian Hamiltonian could all be real if the Hamiltonian had an antilinear symmetry such as PT stimulated new insight into the underlying structure of quantum mechanics. Specifically, it led to the realization that Hilbert space could be richer than the established Dirac approach of constructing inner products out of ket vectors and their Hermitian conjugate bra vectors. With antilinear symmetry one must instead build inner products out of ket vectors and their antilinear conjugates, and it is these inner products that would be time independent in the non-Hermitian but antilinearly symmetric case even as the standard Dirac inner products would not be. Moreover, and in a sense quite remarkably, antilinear symmetry could address not only the temporal behavior of the inner product but also the issue of its overall sign, with antilinear symmetry being capable of yielding a positive inner product in situations such as fourth-order derivative quantum field theories where the standard Dirac inner product is found to have ghostlike negative signature. Antilinear symmetry thus solves the ghost problem in such theories by showing that they are being formulated in the wrong Hilbert space, with antilinear symmetry providing a Hilbert space that is ghost free. Antilinear symmetry does not actually get rid of the ghost states. Rather, it shows that the reasoning that led one to think that ghosts were present in the first place is faulty. Implications of our results for constructing unitary quantum theories of gravity are presented.
Paths of unitary access to exceptional points
Authors: Znojil Miloslav
Published: November 2021

With an innovative idea of acceptability and usefulness of the non-Hermitian representations of Hamiltonians for the description of unitary quantum systems (dating back to the Dyson’s papers), the community of quantum physicists was offered a new and powerful tool for the building of models of quantum phase transitions. In this paper the mechanism of such transitions is discussed from the point of view of mathematics. The emergence of the direct access to the instant of transition (i.e., to the Kato’s exceptional point) is attributed to the underlying split of several roles played by the traditional single Hilbert space of states

ℒ

into a triplet (viz., in our notation, spaces

K

and

ℋ

besides the conventional

ℒ

). Although this explains the abrupt, quantum-catastrophic nature of the change of phase (i.e., the loss of observability) caused by an infinitesimal change of parameters, the explicit description of the unitarity-preserving corridors of access to the phenomenologically relevant exceptional points remained unclear. In the paper some of the recent results in this direction are summarized and critically reviewed.
Flow stress characterization of magnesium alloys at elevated temperatures: A review
Authors: Yoo J D , Kim M C , Kim E J , Razali M K , Joun M S
Published: November 2021

The flow behaviors of magnesium alloys are too complicated to be simply formulated in a mathematical form. Most researches have based metallurgically or phenomenologically on specific functions with many constants, which could be applied only to the limited magnesium alloys under specific conditions. In this study, a review on the studies of flow stress characterization of magnesium alloys is conducted and the possibility of using the traditional piecewise C-m model and its extension to characterize the magnesium alloys is emphasized. The formulations of major flow models are given with three typical applications to magnesium alloy AZ80 and its characteristics are demonstrated through comparison of the fitted flow behaviors with their associated experiments and various flow stress models including Arrehenius model, four Ludwik family models (Johnson Cook, Modified Johnson-Cook, Hensel-Spittel, Sutton-Luo), two Voce family models (Ebrahimi et al., Razali et al.) and C-m models.
Modelling and Numerical simulation of Nano-enhanced PV-PCM System for Heat Transfer Augmentation from the Panel
Authors: Charles Divyateja B , Unnikrishnan K S , Rohinikumar B
Published: November 2021

Phase change materials (PCMs) can effectively cool photovoltaic (PV) panels by the passive cooling technique, thereby enhancing its direct energy conversion efficiency. However, generally, PCMs have low thermal conductivity, and different methods can be employed to improve the heat transfer rate. Cooling techniques based on phase change materials (PCMs) enhanced by nano-sized solid particles are very promising. In this paper, a mathematical model is developed to simulate the performance analysis of PV attached with nano-enhanced PCM (NEPCM) integrated with fins and compare the same with that of pure PCM case. The system is oriented in a horizontal position and subjected to constant solar radiation flux of 1000 W/m
2. The PCM selected is RT25HC, and the nanoparticle used is CuO for the numerical study. The effects of volumetric concentrations (0%, 2%, and 4%) and fin number on the performance of the system are investigated numerically. Results show that adding nanoparticles is more effective in no fin case compared to finned cases. The maximum reduction in average PV temperature of 2.02 °C is obtained for no fin case with the nanoparticles’ volumetric concentration of 4%. Further enhancement in liquid fraction and energy storage in NEPCM is also achieved compared to the pure PCM system.
Research on Governor Parameter Optimization to Suppress Ultra-Low Frequency Oscillation of Power System Caused by Hydropower Unit
Authors: Yan Wei , Sun Yunbang
Published: November 2021

In the actual power system with hydropower, long-time and ultra-low frequency oscillation events occur many times. It is found that the unreasonable setting of governor parameters is an important reason for the oscillation. Firstly, the single machine on load system model is used to analyse the relationship between the PID parameters of the governor and the system stability, then the relationship between oscillation mode and PID parameters of governor is analyzed by eigenvalue analysis method, and the negative damping provided by speed regulation system is analyzed by damping torque method, and then the particle swarm optimization algorithm is used to optimize the PID parameters. Through the analysis of the step response of the single machine system before and after the optimization and the damping torque coefficient provided by the speed regulation system, it shows the effectiveness of the optimization algorithm. Finally, in the simulation platform MATLAB/SIMULINK, a single machine load system model which is closer to the actual power grid is built. The governor parameters of the generator are simulated and verified, and the PID parameters are adjusted by using the parameters obtained by the optimization algorithm. The results show that the optimized parameters have a good suppression for the ultra-low frequency oscillation.
Modelling and simulation of house load operation of HPR1000 NPP
Authors: Chen Xiaowei , Sun Hui , Zhai Changchun , Zhang Qingliang
Published: November 2021

In this paper, the house load operation of the unit is evaluated, taking the third-generation Nuclear Power Plant (NPP) HPR1000 as an example, considering the primary loop, the secondary loop and the entire on-site electrical power systems. The main work of this study is as following: Firstly, acceptance criteria and specific numerical requirements are set out; the simulation result should meet the relevant criteria. Secondly, the Simulink simulation model of the entire system is built in detail, which can be divided into primary loop, secondary loop and on-site electrical power system parts, with emphasis on the simulation modelling of the turbine generator unit. The component models of each part and their corresponding connection relationships of each part are shown and given. Finally, a house load operation simulation is performed, and the result is compared with the acceptance criteria to verify that whether the generator has the ability to transfer to house load operation as designed.
Application of extraction steam graded heat storage in peak shaving of condensing units
Authors: Zou Siyu , Zheng Puyan , Zhu Qunzhi , Bai Tianyu , Wei Qingyuan , Wei Guoqing
Published: November 2021

In order to alleviate the peak shaving pressure of power grid and further improve the deep peak shaving capacity of coal-fired units, this paper applies staged heat storage to condensing units. Under the condition of constant boiler load, the heat of regenerative steam extraction is stored to reduce the electrical load output of the unit. Taking a 660MW ultra-supercritical unit as an example,30%THA,40%THA and 50%THA were taken as the initial conditions of heat storage respectively to discuss the peak shaving range and power regeneration efficiency of different extraction steam positions for heat storage. The results show that the “storage 1# HP heater extraction steam” scheme with “two-stage three tank” heat storage and release structure has the largest peak shaving range of 37.3%~56.9% under 50% initial conditions. When the “two-stage three tank” heat storage and release structure selects the “storage 1# HP heater extraction steam ”scheme under 40% initial working condition, the “power regeneration efficiency” reaches the highest——78.3%. And the “power regeneration efficiency” of “two stage three tank” storage structure are always higher than the “single-stage” storage structure.
Research on typical application in distribution station area
Authors: Lu Dan , Liu Yang , Li Jungang , Zhang Linjuan , Xu Changqing , Wang Lili , Guo Jianyu
Published: November 2021

The traditional power distribution station area lacks advanced functions for power distribution, and it is not conducive to operation and maintenance management. In order to improve the intelligent level of the distribution station area, it is constructed around with the intelligent distribution transformer terminal. Take intelligent distribution transformer terminal as the centre, the schemes of some typical applications, such as topology identification, line impedance analysis and three-phase unbalanced governance, are researched and designed to support the construction of distribution station area.
Oscillation analysis of doubly-fed unit considering wind speed variation
Authors: Wan Ke
Published: November 2021

Tower shadow effect and wind shear may cause power oscillation of the unit. In order to study the influence of tower shadow effect and wind shear on the output power of wind turbine, a doubly-fed turbine was taken as an example. Firstly, the influence of tower shadow effect and wind shear was considered to study the periodic power fluctuation characteristics of wind turbines. Then, according to the dynamic model of mechanical transmission mechanism, the influences of the inertia constants of generator, fan and the stiffness coefficient of the shaft system on the transient performance of the wind power generation system were considered respectively. Finally, a single machine infinite bus system model including wind speed model is built on PSCAD/EMTDC platform for simulation. The results show that the tower shadow effect and wind shear component can cause the power fluctuation of the turbine. When the power fluctuation frequency of the turbine is equal to the natural oscillation frequency of the wind turbine shafting, the resonance of the turbine occurs, and the amplitude of oscillation is the largest. Changing the transmission parameters will affect the power fluctuation amplitude and speed response speed of the unit.
Application of anti integral saturation cascade PID control algorithm in superheated steam temperature control
Authors: Sun Zhe , Liu Chunhui , Li Ming , Zhao Junda , Xu Yao
Published: November 2021

At present, most units adopt the superheated steam temperature control system with cascade PID control structure. However, because most cascade PID control algorithms have no anti-integral saturation function, the automatic control of boiler superheated steam temperature cannot be put into operation normally. On the existing cascade PID superheated steam temperature regulation system, we judge the deviation value of the main regulator and the output value of the auxiliary regulator, and cancel the integration function at an appropriate time. When the input deviation signal turns over, the regulating system can immediately enter the normal regulating state, so that the cascade PID superheated steam temperature regulating system can timely and accurately regulate the superheated steam temperature. The fuel cost is saved by about 155,600 yuan per year.
Research on Real-time Monitoring of Launch Vehicle Deformation Using Fiber Bragg Grating Sensor
Authors: Liang Zhuang , Zhang Yulin
Published: November 2021

To solve the problem that the curvature information of the large flexible rocket body affects the attitude control of the rocket body, a shape reconstruction method based on optical fiber strain sensing is proposed in this paper, which can measure the bow deformation and vibration state of the rocket in real time as the input data for adjusting the attitude control of the rocket. In this scheme, the dynamics of flexible rocket can be solved stably and quickly. In order to verify the reconstruction method, the beam model was used as the experimental analysis object, and the vibration information such as deformation of the beam model was identified through the strain value measured by fiber Bragg grating (FBG) sensors. The results show that the deformation reconstruction method can well restore the deformation and rotation angle of the beam system and has good stability and real-time performance. This method can provide a theoretical basis for the real-time deformation calculation and high-precision attitude control of future flexible launch vehicle.
A predictive control method for reducing power backflow in DC/AC matrix converter
Authors: Xia Zhipeng , Jin Ping , Chang Ling
Published: November 2021

In recent years, DC/AC matrix converter with higher power density have become an attractive alternative to traditional voltage source converters. The traditional PI control has been employed to achieve accurate control, but its dynamic response and stability need to be improved. In this paper, a model predictive control (MPC) with reducing power backflow is introduced in an isolated DC/AC matrix converter with a loosely coupled high-frequency transformer (LCHFT). Prediction model and optimal function model are established to improve the dynamic response of the system and reduce the power backflow.
Influences of Pressure ratio and Fluid Temperature on overall Cooling Performances of Ribbed Channel with Film Holes
Authors: Li Yi , Wang Jianhua , Wang Xu , Wu Weilong , Su Hang
Published: November 2021

The previous experiments of overall cooling performances were most conducted using simplified models and under the similar temperature ratio of mainstream to cooling air with real gas turbine operations, and ambient outlet pressure. To discuss the reliability of this type of experimental data, this paper exhibits two series of numerical simulations. Using a real E3 blade as model, which has two-pass rib-roughened channel with inclined film holes, numerical simulations are carried out at the same temperature ratio and pressure ratio, but different fluid temperatures including mainstream and cooling air, and different outlet pressure. The numerical results reveal two important conclusions: 1) At the same outlet pressure, the overall cooling effectiveness on PS is not sensitive to the fluid temperatures, but on SS in the region between two rows of film holes, a higher fluid temperature corresponds to a higher cooling effectiveness. 2) At the same pressure ratio of inlet to outlet, the overall cooling effectiveness on PS and SS is not sensitive to the outlet pressure and fluid temperature.
Control and application of ultra-high voltage insulator cleaning and detecting robot
Authors: Lei Ting , Xie Zhiwen , Wang Ke , Zhong Liqiang , Chen Dekai
Published: November 2021

With the development of global energy Internet and demand for UHV transmission, uHV transmission lines will increase rapidly and become more and more important for national economic development. The uHV transmission lines will increase year by year and become increasingly important to the economic development of the country. It is necessary to study the cleaning and detection technology of transmission line insulators that the insulators of UHVDC transmission lines such as large leakage rate, low detection efficiency and difficult cleaning of insulators. Therefore, the development of uhv transmission line insulator hot-line cleaning robot and detection integration has important engineering significance and practical value to improve the level of the operation of the uhv power transmission engineering maintenance, safe and reliable operation of the protection of uhv transmission lines. In this paper, the research on the integrated robot for live cleaning and detection of uHV transmission line insulators will greatly promote the live operation of UHV transmission lines in China. It can be directly applied to the live operation of UHV DC and can be promoted nationwide.
Research on control technology of tip-tilt mirror system in adaptive optics
Authors: Zhao Dechun , Song Yansong , Liu Yang , Zhang Baishuo , Liu Tianci
Published: November 2021

In order to solve the control problem of the tip-tilt mirror under the unknown disturbance, a nonlinear disturbance observer with adaptive ability based on the sliding mode control is designed.Firstly, the sliding mode control method of the tip-tilt mirror system is established with Lyapunov functions. Secondly, an adaptive nonlinear disturbance observer is developed on a basis of observer model. Finally, the proposed sliding mode control method is combined with a nonlinear observer with adaptive capability to achieve the goal of improving the control accuracy of the system, while also reducing the chattering caused by the system. The experiment proves that this method is achievable. The experimental results show that the tracking error of the azimuth axis is reduced from 1.637μrad to 1.083μrad, and the accuracy is improved by about 51.2%. The tracking error of the pitch axis is reduced from 1.966μrad to 1.614μrad, and the accuracy is improved by about 21.8%. This method can greatly weaken the inherent chattering and external disturbance of the system, and improve the stability of the tip-tilt mirror system.
Heating load prediction based on particle swarm optimization support vector machine
Authors: Chen Xiuchao , Wang Shenghui , Jin Xing
Published: November 2021

Heating load is affected by many uncertain factors, which makes it show certain randomness. To further improve the heating load forecasting accuracy, reduce the prediction error, using cross validation (CV) ideology in the choice of a model of performance evaluation and the superiority, combined with the advantages of particle swarm optimization (PSO), which is easy to implement and has stronger global optimization ability, the important parameters (penalty factor C and RBF kernel function parameter γ) are optimized, and the best parameters are automatically found in the training set, so as to obtain the best training model. Compared with other algorithms, the model precision of this method is improved a lot, and the prediction result is more accurate.
Introduction to the method of estimating time-domain response based on amplitude-frequency characteristics
Authors: Wang Mingrui , Xu Mei , Wang Jiangfeng , Guo Yingying
Published: November 2021

How to use the amplitude-frequency characteristics to reconstruct the signal to obtain the time-domain response has always been a concern in the field of nuclear electromagnetic protection. So far, in practical applications, parametric modeling and non-parametric modeling have been used to solve related problems. This article summarizes the research and development of using amplitude-frequency characteristics to recover time-domain signals in the field of nuclear electromagnetic pulse protection, and briefly introduces the shortcomings of the two methods in combination with specific experiments.
A simple polymerization control method for the air conditioning cluster
Authors: Xu Zhenwu , Han Xueshan
Published: November 2021

Taking the air conditioner cluster as the object, under the condition of individual perception and controllable state of the air conditioner, the cluster state is given a considerable and controllable function. In the analysis of the load model of a single air conditioner, considering the comfort of indoor temperature, the characteristics of on and off are given, that is, the cycle of on time and off time; on this basis, the air conditioning clusters are divided according to the same or similar switching cycles, thereby forming a switching strategy of series and parallel groups to achieve load balance. In the on state, if the adjustment of the power of the air conditioner itself is not considered, a simple aggregation control method is given. The analysis of numerical examples shows that this method is simple and reliable.
Load Rejection Performance Analysis of HPR1000 NPP in the UK Grid
Authors: Zhang Qingliang , Sun Hui , Zhai Changchun , Chen Xiaowei
Published: November 2021

In this study, the full range of load rejection performance of HPR1000 NPP is evaluated against the UK Grid Code considering the primary loop, the secondary loop, and the electrical system. The main work of this paper includes three parts. Firstly, the UK grid operational requirements are introduced including frequency requirements, voltage requirements, power requirements, etc. The criteria and specific numerical requirements to be followed in the simulated steady-state and transient states are listed, and the simulation results should meet the grid operation requirements; Secondly, the Simulink simulation model of the whole system is built in detail, and the simulation model can be divided into NSSS, turbine generator, and electrical power system sections. The component modules of each part and their corresponding connection relationships of each part are shown and presented; Finally, a load rejection simulation is performed to demonstrate that the unit has the ability to regulate its active power output and frequency as required in the Grid Code.
Design and Application of Multiple Adaptability Evaluation Algorithms Based on UHVDC Digital Simulation Operating System
Authors: Song Zhiming , Xing Fengmin , Mou Li , Zhang Xinyi , Zhang Yanjie
Published: November 2021

The digitally simulated UHVDC system provides an all-round, full-process, and full-scenario high-fidelity training and teaching platform for the switching operation of the UHVDC system, which can fully meet the training requirements of the operation and maintenance personnel of the converter station. In order to solve the problem of inaccurate evaluation due to the existence of multiple operation procedures for an operation target, an improved digital simulation system based on multiple adaptive evaluation algorithms was designed: the teacher uses a modular combination method to generate a standard operating procedure as the main line, and then uses the trainee’s simulated operating procedure as a supplement to jointly form a standard answer to adapt to the different operating procedures of the same operating task for the trainees. Based on this system, it can solve the problem of inaccurate evaluation caused by millions of answers in the simulation operation evaluation process. It provides fast, efficient and accurate evaluation results for the digital simulated UHVDC system switching operation procedure.
Transmission line inspection data visualization system based on 3D GIS
Authors: Quan Hao , Shi Xishuang , Li Cheng , Geng Yanxu , Huang Fei
Published: November 2021

In order to meet the needs of safe and efficient patrol operation and maintenance of modern smart grid, aiming at the poor quality of current transmission line patrol inspection, a design method of transmission line patrol data visualization system based on 3D GIS is proposed. By optimizing the system hardware structure configuration combined with 3D GIS technology, the function and structure of transmission line visual management system are introduced. The accurate collection and processing of transmission line inspection data and the display of inspection route are realized by using three-dimensional GIS technology. Finally, the experiment shows that the transmission line inspection data visualization system based on Three-dimensional GIS has higher practicability and accuracy in the process of practical application, and fully meets the research requirements.
Research on Visual Detection Algorithm of 500kV High Voltage Live Operating Robot
Authors: Guo Suping , Deng Jun , Fan Yahui , Dai Sijing
Published: November 2021

The 500kV transmission line is exposed to the outdoor for a long time. It is affected by complex climate charge change and other factors which leads to line connection parts bolt loosening, wire breaking and fixture damage and other line failures. In order to ensure the stable transmission of electric energy, power operators need to wear shielding suits and work in the high-risk and high-voltage environment. Use of electric power operation robot instead of manual operation is an effective way to liberate maintenance staff labor. But robots still have some problems such as low degree of automation and low efficiency of power operation. Machine vision detection technology in recent years has been widely used in major areas including deep learning as emerging visual detection technology shows excellent performance. In this paper, the vision detection algorithm is studied respectively for the bolt fastening end working device and wire repairing end working device of the live transmission line robot to improve the operating efficiency of the robot.
Research on Secure Data Transmission Algorithm Based on Confidence of Wireless Opportunistic Networks for Energy Internet
Authors: Cao Yaofu , Li Xiaomeng , Liu Junwen , Li Chengwei , Yan Junlu , Zhao Jingcheng
Published: November 2021

The Energy Internet is a leading development direction for the modernized and intelligent transformation of the power grid, and a new type of infrastructure that supports the high-quality development of the economy and society. With the access of a variety of mobile terminals, security is one of the most important challenges faced in the construction of Energy Internet. Research on reliable networking and data forwarding strategies on the edge is of great significance to its development. On the basis of analyzing the requirements of typical application scenarios, we introduce in this paper a secure data transmission algorithm based on confidence of wireless opportunistic networks for Energy Internet to resist the influence of malicious behaviours. The simulations of real scenes confirm the advantages of introducing our algorithm on parameters such as the success rate and the delay of data transmission.
Research on Operation Optimization of Central Air Conditioning Cold Source System Based on PSO-SA Algorithm
Authors: Lv Lichao , Wang Du , Chen Ying , Chen Hao , Wei JiaQian
Published: November 2021

This paper takes a data center air-conditioning cold source system as the research object. According to the historical operating data of the cold source system in the transition season, a cold source model is built on the EBSILON platform. The total energy consumption of the cold source system is the research goal. This paper establishes an overall optimization strategy based on PSO-SA. A simulation experiment was conducted on a typical day in the transition season, and the results showed that the optimization strategy can achieve 21.68% energy saving based on the original operation mode when the wet bulb temperature in the transition season is low.
Jointly modelling Cosmic Inflation and Dark Energy
Authors: Dimopoulos Konstantinos
Published: November 2021

Quintessential inflation utilises a single scalar field to account for the observations of both cosmic inflation and dark energy. The requirements for modelling quintessential inflation are described and two explicit successful models are presented in the context of α-attractors and Palatini modified gravity.
SU(2,1)/(SU(2) × U(1)) B − L Higgs Inflation
Authors: Pallis C
Published: November 2021

We present a realization of Higgs inflation within Supergravity which is largely tied to the existence of a pole of order two in the kinetic term of the inflaton field. This pole arises due to the selected Kaehler potential which parameterizes the SU(2,1)/(SU(2) × U(1)) manifold with scalar curvature

R

21

=
−
6
/
N

. The associated superpotential includes, in addition to the Higgs superfields, a stabilizer superfield, respects a B − L gauge and an R symmetries and contains the first allowed nonrenormalizable term. If the coefficient of this term is almost equal to that of the others within about 10−5 and N = 2, the inflationary observables can be done compatible with the present data. The tuning can be eluded if we modify the Kaehler potential associated with the manifold above. In this case, inflation can be realized with just renormalizable superpotential terms and results to higher tensor-to-scalar ratios as N approaches its maximum at N ≃80.
Primordial Black Holes And Gravitational Waves Based On No-Scale Supergravity
Authors: Stamou Ioanna D.
Published: November 2021

In this paper we present a class of models in order to explain the production of Primordial Black Holes (PBHs) and Gravitational Waves (GWs) in the Universe. These models are based on no-scale theory. By breaking the SU(2,1)/SU(2)×U(1) symmetry we fix one of the two chiral fields and we derive effective scalar potentials which are capable of generating PBHs and GWs. As it is known in the literature there is an important unification of the no-scale models, which leads to the Starobinsky effective scalar potential based on the coset SU(2,1)/SU(2)×U(1). We use this unification in order to additionally explain the generation of PBHs and GWs. Concretely, we modify well-known superpotentials, which reduce to Starobinsky-like effective scalar potentials. Thus, we derive scalar potentials which, on the one hand, explain the production of PBHs and GWs and, on the other hand, they conserve the transformation laws, which yield from the parametrization of the coset SU(2,1)/SU(2)×U(1) as well as the unification between the models which are yielded this coset. We numerically evaluate the scalar power spectra with the effective scalar potential based on this theory. Furthermore, we evaluate the fractional abundances of PBHs by comparing two methods the Press–Schechter approach and the peak theory, while focusing on explaining the dark matter in the Universe. By using the resulting scalar power spectrum we evaluate the amount of GWs. All models are in complete consistence with Planck constraints.