Moments of inertia of triaxial nuclei in covariant density functional theory

The covariant density functional theory(CDFT)and five-dimensional collective Hamiltonian(5DCH)are used to analyze the experimental deformation parameters and moments of inertia(MoIs)of 12 triaxial nuclei as extracted by Allmond and Wood[J.M.Allmond and J.L.Wood,Phys.Lett.B 767,226(2017)].We find that the CDFT MoIs are generally smaller than the experimental values but exhibit qualitative consistency with the irrotational flow and experimental data for the relative MoIs,indicating that the intermediate axis exhibites the largest MoI.Additionally,it is found that the pairing interaction collapse could result in nuclei behaving as a rigid-body flow,as exhibited in the^(186-192)Os case.Furthermore,by incorporating enhanced CDFT MoIs(factor of f≈1.55)into the 5DCH,the experimental low-lying energy spectra and deformation parameters are reproduced successfully.Compared with both CDFT and the triaxial rotor model,the 5DCH demonstrates superior agreement with the experimental deformation parameters and low-lying energy spectra,respectively,emphasizing the importance of considering shape fluctuations.

Inertial Entropy and External Validation of Clusterings

Axiomatization of Shannon entropy is a subject that has received lots of attention in the information theory literature.While Shannon entropy is defined on probability distribution,we define a new type of entropy on the set of partitions of finite subsets of metric spaces,which has a rich algebraic structure as a partially ordered set.We propose an axiomatization of an entropy-like measure of partitions of sets of objects located in metric spaces,and we derive an analytic expression of this new type of entropy referred to as inertial entropy.This approach starts with the notion of inertia of a partition and includes a study of the behavior of the sum of square errors of a partition.In this context,we characterize the chain of partitions produced by the Ward hierarchical clustering method.Starting from inertial entropies of partitions,we introduce conditional entropies which,in turn,generate metrics on partitions of finite sets.These metrics are used as external validation tools for clusterings of labeled data sets.The metric generated by inertial entropy can be used to validate data clustering for labeled data sets.This type of validation aims to determine to what extend labeling of the data coincides with the clustering obtained algorithmically,and we obtain a high degree of consistency of the data labeling with the results of several hierarchical clusterings.

The Nature of Inertia Explained Using the Field Theory

Analysis of free fall and acceleration of the mass on the Earth shows that using abstract entities such as absolute space or inertial space to explain mass dynamics leads to the violation of the principle of action and reaction. Many scientists including Newton, Mach, and Einstein recognized that inertial force has no reaction that originates on mass. Einstein calls the lack of reaction to the inertial force a serious criticism of the space-time continuum concept. Presented is the hypothesis that the inertial force develops in an interaction of two masses via the force field. The inertial force created by such a field has reaction force. The dynamic gravitational field predicted is strong enough to be detected in the laboratory. This article describes the laboratory experiment which can prove or disprove the hypothesis of the dynamic gravitational field. The inertial force, calculated using the equation for the dynamic gravitational field, agrees with the behavior of inertial force observed in the experiments on the Earth. The movement of the planets in our solar system calculated using that equation is the same as that calculated using Newton’s method. The space properties calculated by the candidate equation explain the aberration of light and the results of light propagation experiments. The dynamic gravitational field can explain the discrepancy between the observed velocity of stars in the galaxy and those predicted by Newton’s theory of gravitation without the need for the dark matter hypothesis.

Addressing Frequency Control Challenges in Future Low-Inertia Power Systems:A Great Britain Perspective

The ambitious global targets on decarbonization present the need for massive integration of renewable generation in power systems,resulting in a significant decrease in the system inertia.In addition to the reduction in system inertia,the transmission system in Great Britain(GB)faces some unique challenges owing to its relatively small capacity,while being decoupled from other transmission systems and with the renewable resources largely non-uniformly distributed across the system.This paper presents opinions and insights on the challenges associated with frequency control in a low-inertia system and the potential solutions from a GB perspective.In this paper,we focus on three main techniques that act over different time scales:synchronous condensers,inertia emulation,and fast frequency response.We evaluate their relative advantages and limitations with learnings from recent research and development projects in GB,along with the opinions on their roles in addressing the frequency control challenges in future low-inertia systems.

Distributed Virtual Inertia Based Control of Multiple Photovoltaic Systems in Autonomous Microgrid

The large inertia of a traditional power system slows down system's frequency response but also allows decent time for controlling the system.Since an autonomous renewable microgrid usually has much smaller inertia,the control system must be very fast and accurate to fight against the small inertia and uncertainties.To reduce the demanding requirements on control,this paper proposes to increase the inertia of photovoltaic(PV) system through inertia emulation.The inertia emulation is realized by controlling the charging/discharging of the direct current(DC)-link capacitor over a certain range and adjusting the PV generation when it is feasible and/or necessary.By well designing the inertia,the DC-link capacitor parameters and the control range,the negative impact of inertia emulation on energy efficiency can be reduced.The proposed algorithm can be integrated with distributed generation setting algorithms to improve dynamic performance and lower implementation requirements.Simulation studies demonstrate the effectiveness of the proposed solution.

Challenges for a reduced inertia power system due to the large-scale integration of renewable energy

This paper reports on the status of technology development under a national project launched in 2019 to address the problem of decreased system inertia associated with the large-scale integration of renewable energy.The project comprises two parts:the development of a system inertia observation technology using a continuous monitoring system to observe inertia and development of an inverter equipped with a function to provide virtual inertia as a countermeasure device.Utilizing both these efforts,the project aims to facilitate the introduction of renewable energy in the future with minimum restrictions.It was confirmed that the trend of inertia observed with the developed method was generally the same as that of the total inertia of synchronous machines observed by an electric utility.The effectiveness of the countermeasure device in reducing the frequency swing during a disturbance was confirmed through evaluation tests.

Inertia Matching During Dynamic Simulation of Vehicle Drive System on Test Bench

Framework and basic parameters of a test bench for motor drive system of electric vehicle (EV) are illuminated. Two kinds of electric drive models, one was for the electric vehicle drived on real road, the other was for that on test bench, are put forward. Then, dynamic analysis of these models is made in detail. Inertia matching method of the test bench is researched and some useful formulas and graphs are brought forward. The experiment of an electric bus is introduced in order to explain the usage of this inertia matching method.

ELECTRO-HYDRAULIC COMPOUND CONTROL METHOD AND CHARACTERISTIC OF CONTROL FOR TENSION SYSTEM WITH HIGH INERTIA LOADS

Based on the pressure regulation circuit adopting electro-hydraulic proportional relief valve to control tension, a new type of electro-hydraulic compound control circuit with throttle control unit is presented, which can obtain optimal dynamic damping ratio through real-time altering pressure-flow gain of the throttle control unit, improve the dynamic characteristic of tension follow-up control for the tension system with high inertia loads. Moreover, the characteristic when the cable linear velocity variation causes change of tension is investigated, and a compound control strategy is proposed. The theoretical analysis and experimental results show that the electro-hydraulic compound control circuit is effective and the characteristic of the compound control strategy is satisfactory.

Superconducting energy storage technology-based synthetic inertia system control to enhance frequency dynamic performance in microgrids with high renewable penetration

With high penetration of renewable energy sources(RESs)in modern power systems,system frequency becomes more prone to fluctuation as RESs do not naturally have inertial properties.A conventional energy storage system(ESS)based on a battery has been used to tackle the shortage in system inertia but has low and short-term power support during the disturbance.To address the issues,this paper proposes a new synthetic inertia control(SIC)design with a superconducting magnetic energy storage(SMES)system to mimic the necessary inertia power and damping properties in a short time and thereby regulate the microgrid(µG)frequency during disturbances.In addition,system frequency deviation is reduced by employing the proportional-integral(PI)controller with the proposed SIC system.The efficacy of the proposed SIC system is validated by comparison with the conventional ESS and SMES systems without using the PI controller,under various load/renewable perturbations,nonlinearities,and uncertainties.The simulation results highlight that the proposed system with SMES can efficiently manage several disturbances and high system uncertainty compared to the conventional ESS and SMES systems,without using the PI controller.

Parameter design and performance analysis of zero inertia continuously variable transmission system

In order to solve the problem of weak power performance of vehicle equipped with continuously variable transmission(CVT) system working under transient operating conditions, a new CVT equipped with planetary gear mechanism and flywheel was researched, a design method of transmission parameter optimization was proposed, and the comprehensive matching control strategy was established for the new transmission system. Fuzzy controllers for throttle opening and CVT speed ratio were designed, and power performance and fuel economy of both vehicles respectively equipped with conventional CVT system and new transmission system wrere compared and analyzed by simulation. The results show that power performance and fuel economy of the vehicle equipped with new transmission system are better than that equipped with conventional CVT, thus the rationality of the parameter design method and control algorithm are verified.

Determining the moment of inertia of triaxial Mars with updated global gravity models

The principal moments of inertia(PMIs)with the principal axes are usually taken as the dynamic figure parameters of Mars;they can be deduced from satellite-observed degree-two gravitational potentials in recent global gravity models and from the dynamic ellipticities resulting from precession observations.These PMIs are natural and significant for the geodetic,geophysical,and geodynamic problems of Mars,which are functions of internal density distributions.In this study,a closed and concise formula for determining the PMIs of the entire planet and its core was developed based on the second invariants of gravity and a multipole expansion.We deduced the polar oblateness J^(2)and the equatorial ellipticity J_(22)of Mars to be 1.9566×10^(−3)and 6.3106×10^(−5),respectively.The preferred principal moments of inertia of Mars are A=2.66589×1036 kg·m^(2),B=2.66775×10^(36)kg·m^(2),and C=2.68125×10^(36)kg·m^(2).These values indicate that Mar is slightly triaxial.The equatorial principal moment of inertia of the Martian core is 1.46008×10^(35)kg·m^(2),accounting for~5.47%of the planet’s PMI;this result is critical for investigating the density and size of the core of Mars,and the planet’s free core nutation.

The Thermal Inertia Characteristics of the System Ocean-Atmosphere

To estimate the time delay between the planetary temperature change and the change of the incoming solar radiation fraction absorbed by the ocean and the atmosphere, the analytical energy balance model is presented. The model generalization allows of using averaged data for model parameterization. Using the model, the time delay is investigated on four model cases of absorbed radiation change. The interconnections among the time delay, the planetary thermal inertia and the ocean active layer depth are established.

Introduction to the Theory of Relativity of Non-Inertial Systems and Mechanics of the Universe

The physical nature of inertia is explored. Authors, based on Mach’s principle, offer hypothesis of the induction nature of inertia and theory, which allows extend the principle of relativity to the non-inertial reference systems. The system of differential equations, which eliminates the shortcomings of Newtonian mechanics and Special Theory of Relativity (STR) was composed according to this theory. Row of concrete calculations and explanations are made using the theory. Reason of constancy orbital velocities of galaxies is found out and way of its calculations is shown. Existence of dark matter and the new particles (neutralinos, axons, space vacuum etc.) is prejudiced. Axial deviation of the ray of light in gravitational field is explained and calculated. An example of calculation of the Mercury’s orbital motion is made and complex planets’ trajectories are explained by the action of new field with induction nature. Flat rotation of celestial bodies and shaping of planets’ rings (like the Saturn’s rings) are explained. Indistinguishability of Doppler and Einstein’s effects for terrestrial observer is shown.

Disjointed Equivalence of Gravitational and Inertial Mass

Problem—Contemporary physics offers no underlying reason for the equivalence of inertial and gravitational mass. Approach—The equivalence is examined from the new physics provided by the cordus theory, being a non-local hidden-variable (NLHV) theory. Mathematical formalisms are derived for masses and observers in different fabric densities. Findings—A disjointed equivalence is predicted, whereby inertial and gravitational masses are equivalent in any one situation, but a different equivalence holds when the fabric densities change. Consequently this theory predicts that the gravitational constant G varies with fabric density, and hence would be different across the universe and across time. Not only is the gravitational constant non-constant, but the formulation of gravitation changes with fabric density. Specifically, the theory predicts gravity is stronger at genesis (and the end of the universe) such that orbit velocity vB ∝ (where rB is orbit radius), compared to weaker gravitation at middle life epochs with rB ∝ . The current Earth location and epoch correspond to the latter case, i.e. Newtonian gravitation is recovered. The findings disfavour the existence of both dark energy and dark matter, and instead attribute these effects to differences in the fabric density. Originality—The work makes the contribution of deriving a mass equivalence relationship that includes fabric density, identifying a disjointed mass equivalence, and showing that the gravitation formulation itself changes with relative fabric densities.

含高比例新能源的电力系统频率稳定研究综述

作为“双碳”战略目标的关键载体,含高比例新能源的电力系统具有惯量水平低、调频能力差、抗扰性能弱等特征,对频率稳定带来了全新挑战,迫切需要深入认识能源转型背景下的频率稳定形态。该文按照“建模分析—稳定评估—调频控制”的路线,归纳近年来国内外关于频率稳定的研究及其应用进展。首先,梳理现有频率稳定定义的特点,将其引申为考虑暂态频率安全的广义频率稳定概念,分析含高比例新能源电力系统的频率响应过程;按照系统全局频率和网络节点频率两个视角分析现有特性建模与分析方法,分别总结频率稳定性、频率安全性的评估方法与评估指标,初步建立考虑频率时空分布特性的节点频率安全性指标;列举并归类源网荷储多主体参与系统调频的控制策略,分析相关频率调控措施的特点;最后,结合现有研究进展,对含高比例新能源的电力系统在频率响应特性建模、频率稳定机理评估以及频率稳定协调控制方面的未来发展方向和研究趋势进行展望。

Moments of Inertia, Magnetic Dipole Moments, and Electric Quadrupole Moments of the Lithium Isotopes

The single-particle Schrödinger fluid model is designed mainly to calculate the moments of inertia of the axially symmetric deformed nuclei by assuming that each nucleon in the nucleus is moving in a single-particle potential which is deformed with time t, through its parametric dependence on a classical shape variable α(t). Also, the Nilsson model is designed for the calculations of the single-particle energy levels, the magnetic dipole moments, and the electric quadrupole moments of axially symmetric deformed nuclei by assuming that all the nucleons are moving in the field of an anisotropic oscillator potential. On the other hand, the nuclear superfluidity model is designed for the calculations of the nuclear moments of inertia and the electric quadrupole moments of deformed nuclei which have no axes of symmetry by assuming that the nucleons are moving in a quadruple deformed potential. Furthermore, the cranked Nilsson model is designed for the calculations of the total nuclear energy and the quadrupole moments of deformed nuclei which have no axes of symmetry by modifying the Nilsson potential to include second and fourth order oscillations. Accordingly, to investigate whether the six p-shell isotopes 6Li, 7Li, 8Li, 9Li, 10Li, and 11Li have axes of symmetry or not, we applied the four mentioned models to each nucleus by calculating their moments of inertia, their magnetic dipole moments, and their electric quadrupole moments by varying the deformation parameter β and the non-axiality parameter γ in wide ranges of values for this reason. Hence for the assumption that these isotopes are deformed and have axes of symmetry, we applied the single-particle Schrödinger fluid model and the Nilsson model. On the other hand, for the assumption that these isotopes are deformed and have no axes of symmetry, we applied the cranked Nilsson model and the nuclear super fluidity model. As a result of our calculations, we can conclude that the nucleus 6Li may be assumed to be deformed and has an axis of symmetry.

基于系统聚类法的含新能源电力系统分区策略

为实现含新能源电力系统的惯量分布特性的有效评估,提出一种基于系统聚类法的含新能源电力系统分区策略。首先分析新能源机组惯量与同步机组惯量之间的差异;其次构建节点惯量响应模型,分析节点惯量相关因素的特性;然后通过主成分分析对影响节点惯量的主导变量进行降维,将降维后的变量应用系统聚类法对节点进行聚类分区;最后通过系统辨识得到区域惯量,评判出整个系统惯量的空间分布。在仿真软件中搭建改进的IEEE 10机39节点模型验证了分区策略的合理性。

超级电容参与风电调频的动态响应优化策略

随着风电渗透率的不断提高,电力系统逐步呈现低惯量的特征。低惯量系统在故障时的频率变化率(RoCoF)和最大频率偏差显著增大,传统频率控制方法效果减弱,频率的安全、稳定面临挑战。针对上述问题,先于一次调频动作的快速频率响应(FFR)已成为解决低惯量系统频率稳定问题的重要手段。首先,建立风-火-储电力系统频率响应模型,分析FFR调频资源对低惯量系统频率响应的影响;其次,基于模糊逻辑推理,提出了一种超级电容参与风电调频的储能动态响应优化策略以控制储能,使其能够动态响应系统频率变化,在频率跌落期遏制频率跌落,在频率恢复期调控储能恢复功率以维持荷电状态稳定;最后,对提出的控制策略进行仿真验证。仿真结果表明,所提策略能够利用超级电容快速动态响应系统频率变化,从而为低惯量系统提供功率支撑,弥补风电调频的不足,相较传统的风电机组虚拟惯量控制策略,在减小最大RoCoF及抑制最大频率偏差效果上均有大幅提升。

跟网型电化学储能虚拟惯性常数的常数化计算方法

在包含跟网型储能虚拟惯量控制的新型电力系统频率响应(SFR)建模应用中,跟网型储能的虚拟惯性常数具有时变特性,且无法聚合求解系统等效惯性常数,导致不能构建完整的SFR模型。基于此,提出了跟网型电化学储能虚拟惯性常数的常数化计算方法,通过计算具有等效惯性常数-能量支撑效果的常数化虚拟惯性常数,实现系统等效惯性常数的聚合求解。该方法根据能量变化关键节点和动态过程的约束条件,以及跟网型储能虚拟惯量响应的两阶段相异特征,建立了具有最相近能量变化的目标函数,以分段求解常数化虚拟惯性常数。最后,通过建立SFR模型,结合时域仿真法和相关评价指标验证了计算结果的精确性。

大扰动下电力系统惯性时空分布特性的表征形式初探

已有关于系统惯性时空分布(spatial-temporal distribution of system inertia,SDSI)的研究大多聚焦于惯量估计,而对其概念的表征并不统一,也缺乏对其性质的深入剖析与相关概念的系统梳理与辨析。该文试图探索大扰动下系统惯性时空分布特性的表征形式。基于频率动态过程分析剖析了惯性时空分布特性,提出系统节点惯量概念并给出该参量的性质描述参量,基于惯性物理机理提出了这些参量的量化分析方法并推导了相关系数的差分计算公式。仿真算例验证了对系统惯性时空分布特性所做的分析与判断,利用所提出的表征形式可全面而规范地表征系统惯性时空分布特征。研究可为电力系统惯性时空分布特性表征体系的构建提供参考。