Radial Nodes Research Articles

Real Power Loss Minimization Considering Multiple DGs and Battery in Distribution System

The Distributed Generators (DGs) in the distribution systems play major roles, one of them being minimization of the network losses. The undesirable or intermittent nature is one of the challenges in maintaining the power between the DG and the grid. The main advantage of a battery energy storage system is to support the grid by storing the energy in it. The work articulated here is sizing and placement of DG in the distribution system and to support the grid, the battery storage is placed after the placement of the DGs. The heuristic approach namely Particle Swarm Optimization (PSO) is used for sizing and placement of DGs and the genetic algorithm is used for the placement of the battery energy storage system in the standard IEEE networks such as IEEE-33, IEEE-69, IEEE-118 radial node distribution systems. The operation of the battery in accordance with the state of charge is also presented. The MATLAB software is used for simulation and the results obtained are promising.

Shell-confined atom and plasma: Incidental degeneracy, metallic character, and information entropy

Shell confined atom can serve as a generalized model to explain both \emph{free} and \emph{confined} condition. In this scenario, an atom is trapped inside two concentric spheres of inner $(R_{a})$ and outer $(R_{b})$ radius. The choice of $R_{a}, R_{b}$ renders four different quantum mechanical systems. In hydrogenic atom, they are termed as (a) free hydrogen atom (FHA) (b) confined hydrogen atom (CHA) (c) shell-confined hydrogen atom (SCHA) (d) left-confined hydrogen atom (LCHA). By placing $R_{a}, R_{b}$ at the location of radial nodes of respective \emph{free} $n,\ell$ states, a new kind of degeneracy may arise. At a given $n$ of FHA, there exists $\frac{n(n+1)(n+2)}{6}$ number of iso-energic states with energy $-\frac{Z^{2}}{2n^{2}}$. Furthermore, within a given $n$, the individual contribution of each of these four potentials has also been enumerated. This incidental degeneracy concept is further explored and analyzed in certain well-known \emph{plasma} (Debye and exponential cosine screened) systems. Multipole oscillator strength, $f^{(k)}$, and polarizability, $\alpha^{(k)}$, are evaluated for (a)-(d) in some low-lying states $(k=1-4)$. In excited states, \emph{negative} polarizability is also observed. In this context, metallic behavior of H-like systems in SCHA is discussed and demonstrated. Additionally analytical closed-form expression of $f^{(k)}$ and $\alpha^{(k)}$ are reported for $1s,2s,2p,3d,4f,5g$ states of FHA. Finally, Shannon entropy and Onicescu {\color{red}information} energies are investigated in ground state in SCHA and LCHA in both position and momentum spaces. Much of the results are reported here for first time.

Reactive Power Support in Radial Distribution Network Using Mine Blast Algorithm

The passive power distribution networks are prone to imperfect voltage profile and higher power losses, especially at the far end of long feeders. The capacitor placement is studied in this article using a novel Mine Blast Algorithm (MBA). The voltage profile improvement and reduction in the net annual cost are also considered along with minimizing the power loss. The optimization problem is formulated and solved in two steps. Firstly, the Voltage Stability Index (VSI) is used to rank the nodes for placement of the capacitors. Secondly, from the priority list of nodes in the previous step, the MBA is utilized to provide the optimal location and sizes of the capacitors ensuring loss minimization, voltage profile improvement, and reduced net annual cost. Finally, the results are tested on 33 and 69 radial node systems in MATLAB. The results for the considered variables are presented which show a significant improvement in active and reactive power loss reduction and voltage profile with lesser reactive power injection.

Trapping of Electrons around Nanoscale Metallic Wires Embedded in a Semiconductor Medium

We predict that conduction electrons in a semiconductor film containing a centered square array of metal nanowires normal to its plane are bound in quantum states around the central wires, if a positive bias voltage is applied between the wires at the square vertices and the latter. We obtain and discuss the eigenenergies and eigenfunctions of two models with different dimensions. The results show that the eigenstates can be grouped into different shells. The energy differences between the shells is typically a few tens of meV, which corresponds to frequencies of emitted or absorbed photons in a range of 3THz to 20THz approximately. These energy differences strongly depend on the bias voltage. We calculate the linear response of individual electrons on the ground level of our models to large-wavelength electromagnetic waves whose electric field is in the plane of the semiconductor film. The computed oscillator strengths are dominated by the transitions to the states in each shell whose wave function has a single radial node line normal to the wave electric field. We include the effect of the image charge induced on the central metal wires and show that it modifies the oscillator strengths so that their sum deviates from the value given by the Thomas-Reiche-Kuhn rule. We report the linear response, or polarizability, versus photon energy, of the studied models and their absorption spectra. The latter show well-defined peaks as expected from the study of the oscillator strengths. We show that the position of these absorption peaks is strongly dependent on the bias voltage so that the frequency of photon absorption or emission in the systems described here is easily tunable. This makes them good candidates for the development of novel infrared devices.

Calculation and Analysis of Critical Heat Flux at LWR Passive Safety Design

Critical heat flux (MDNBR) is one parameter for safe nuclear reactor operation. The magnitude of MDNBR is determined by local heat flux. When it is sufficiently high, it will cause a change in heat equilibrium and deteriorate nuclear fuel structure. To obtain assurance for nuclear reactor safety in safe criteria, Calculation and analysis of Critical heat flux of 630 MWe passive LWR was carried out at steady state and transient condition. The study used COBRA IV-I sub channel program coupled with critical heat flux correlation of EPRI-Columbia and W-3. The program models the core into 1/8 sections, each of which is divided into 83 sub-channels in radial direction and 40 nodes in axial direction, including 8 sub-channels of the hottest assembly. Normalized coast down flow and reactor power decay at initial phase is 10 second after loss of flow accident (LOFA) caused by anticipated primary pump failure. The effects of all input parameters, such as radial nodes, axial nodes, mix coefficient, velocity of coolant mass entering the core and power variation, have been identified. Evaluation of the results of safety calculation indicates that MDNBR, cladding temperature, and hot channel temperature are 1.83, 349°C and 2033°C, respectively. As the licensing limits for those parameters are 1.3, 1850°C, and 2840°C, it is concluded that the design of 630 MWe passive LWR has met the licensing criteria of safety. Modelling for safety analysis of passive LWR employs COBRA IV-I program. The results show that this program can be used to calculate hydraulic safety parameters with sub-channel model.

Evaluation of a radial basis function node refinement algorithm applied to bioheat transfer modeling

Many bioheat transfer problems involve linear/non-linear equations with non-linear or time-dependent boundary conditions. For heat transfer problems, the presence of time and space-dependent functions under Neumann and Mixed type boundary conditions characterize trivial applications in bioengineering, such as thermotherapies, laser surgeries, and burn studies. This greatly increases the complexity of the numerical solution in several problems, requiring fast and accurate numerical solutions. This paper has a main objective evaluate an adaptive mesh refinement radial basis function method strategy for the classical Penne's bioheat transfer modeling. Our numerical results had errors of ~0.1% compared to analytical solutions. Thus, the proposed methodology is accurate and has a low computational cost. For step function heating, two RBF shape parameters were applied, again achieving excellent results. The distributions of the nodes in the solution domain show that the primary source of error in the numerical solutions came from the boundary conditions. This finding should arouse the interest of engineers and scientists in the development of new strategies for problems involving boundary conditions with periodic functions.

Perturbation approach to ab initio effective mass calculations

A degenerate perturbation k⋅p approach for effective mass calculations is implemented in the all-electron density functional theory (DFT) package WIEN2k. The accuracy is tested on major group IVA, IIIA–VA, and IIB–VIA semiconductor materials. Then, the effective mass in graphene and CuI with defects is presented as illustrative applications. For states with significant Cu-d character additional local orbitals with higher principal quantum numbers (more radial nodes) have to be added to the basis set in order to converge the results of the perturbation theory. Caveats related to a difference between velocity and momentum matrix elements are discussed in the context of application of the method to non-local potentials, such as Hartree–Fock/DFT hybrid functionals and DFT+U.

Effect of Dzyaloshinskii-Moriya interaction on magnetic vortex switching driven by radial spin waves

We theoretically investigate the radial-spin-wave induced magnetic vortex switching in the presence of Dzyaloshinskii-Moriya interaction (DMI). From micromagnetic simulations, we observe a circular-to-radial vortex phase transition by increasing the DMI strength. The radial spin-wave excitation spectrum for each magnetization configuration is analyzed, showing that the frequency of spin-wave mode with a given radial node number monotonically increases (decreases) with the DMI parameter of the radial (circular) vortex. Interestingly, we find that the DMI can significantly facilitate the polarity switching of the circular vortex driven by radial spin waves. Our work provides a new insight into the DMI effect on the vortex dynamics and is helpful for designing fast all-magnonic memory devices.

Rossby modes in slowly rotating stars: depth dependence in distorted polytropes with uniform rotation

Context.Large-scale Rossby waves have recently been discovered based on measurements of horizontal surface and near-surface solar flows.Aims.We are interested in understanding why it is only equatorial modes that are observed and in modelling the radial structure of the observed modes. To this aim, we have characterised the radial eigenfunctions ofrmodes for slowly rotating polytropes in uniform rotation.Methods.We followed Provost et al. (1981, A&A, 94, 126) and considered a linear perturbation theory to describe quasi-toroidal stellar adiabatic oscillations in the inviscid case. We used perturbation theory to write the solutions to the fourth order in the rotational frequency of the star. We numerically solved the eigenvalue problem, concentrating on the type of behaviour exhibited where the stratification is nearly adiabatic.Results.We find that for free-surface boundary conditions on a spheroid of non-vanishing surface density,rmodes can only exist forℓ = mspherical harmonics in the inviscid case and we compute their depth dependence and frequencies to leading order. For quasi-adiabatic stratification, the sectoral modes with no radial nodes are the only modes which are almost toroidal and the depth dependence of the corresponding horizontal motion scales asrm. For allrmodes, except the zero radial order sectoral ones, non-adiabatic stratification plays a crucial role in the radial force balance.Conclusions.The lack of quasi-toroidal solutions when stratification is close to neutral, except for the sectoral modes without nodes in radius, follows from the need for both horizontal and radial force balance. In the absence of super- or sub-adiabatic stratification and viscosity, both the horizontal and radial parts of the force balance independently determine the pressure perturbation. The only quasi-toroidal cases in which these constraints on the pressure perturbation are consistent are the special cases whereℓ = mand the horizontal displacement scales withrm.

Generation and measurement of high-order optical vortices by using the cross phase.

We investigate a method for the generation and measurement of high-order optical vortices (OVs) by using the cross phase (CP), which is applied to implement interconversion between Laguerre-Gauss (LG) beams and Hermite-Gaussian beams in the far-field. Experimentally, we generate LG beams, which are a kind of typical OVs, with 20 radial nodes, and measure OVs with topological charges up to 200 via the CP. On this basis, we discuss the relationship between intensity distributions and the waist radius of initial light beams. This work provides an alternative method to generate and measure high-order OVs, which is useful in the fields of optical micro-manipulation, high-dimensional quantum entanglement, and remote sensing of the angular rotation of structured objects.

Parametric Design and Static Performance Comparison of Six Typical Spherical Semi-open Reticulated Shell

By using ANSYS Parametric Design Language (APDL), this paper compiled the parametric design macro program for six types of single-layer semi-open spherical reticulated shell structure. Parametric design of the six types of reticulated shell structure was realized with given parameters of span S, the vector high F, radial node cycles number Nx, ring to symmetric regional copies number Kn, and the upper removed laps Ns. The stress performance of the six types of reticulated shell structure was compared and analyzed. Modelling examples demonstrated that the parametric design macro program is simple, practical and improves the efficiency of the selection of the reticulated shell design and the stress analysis under different geometric parameters. Through the comparative analysis of stress performance, some conclusions with engineering significance were obtained.

Excited Kerr black holes with scalar hair

In the context of complex scalar field coupled to Einstein gravity theory, we present a novel family of solutions of Kerr black holes with excited-state scalar hair inspired by the work of Herdeiro and Radu in [Phys.\ Rev.\ Lett.\ {\bf 112}, 221101 (2014)], which can be regarded as numerical solutions of rotating compact objects with excited scalar hair, including boson stars and black holes. In contrast to Kerr black holes with ground state scalar hair, we find that the first-excited Kerr black holes with scalar hair have two types of nodes, including radial $n_r=1$ and angular $n_\theta=1$ nodes. Moreover, in the case of radial nodes the curves of the mass versus the frequency form nontrivial loops, and in the case of angular nodes the curves can be divided into two kinds: closed and open loops. We also study the dependence of the horizon area on angular momentum and Hawking temperature.

Surgeon-Level Variation in Utilization of Local Staging and Neoadjuvant Therapy for Stage II-III Rectal Adenocarcinoma

IntroductionNeoadjuvant therapy (NT) is the standard of care for clinical stage II-III rectal adenocarcinoma, but utilization remains suboptimal. We aimed to determine the underlying reasons for omission of local staging and NT. MethodsWe conducted a retrospective study of patients with clinical stage II-III or undocumented clinical stage/pathologic stage II-III rectal adenocarcinoma who were treated in 2010–2016 in one of nine Intermountain Healthcare hospitals. The outcomes of omission of local staging and NT were examined with multivariable models. Risk- and reliability-adjusted rates of local staging and NT were calculated for surgeons who treated ≥ 3 patients. Pathologic and long-term outcomes were examined after excluding patients who were not resected or who underwent local excision (N = 11). ResultsLocal staging was omitted in 43/240 (17.9%) patients and NT was omitted in 41/240 (17.1%). The strongest risk factors for local staging and NT omission were upper rectal tumors and surgeons who treated ≤ 3 cases/year. Thirty-six of 41 (87.8%) cases of omitted NT had local staging omitted. Adjusted surgeon-specific local staging rates varied 1.6-fold (56.3–92.4%) and NT rates varied 2.8-fold (34.1–97.1%). Surgeon local staging and NT rates were strongly correlated (r = 0.92). NT was associated with lower rates of positive circumferential radial margins (7.9 vs. 20.0%; P = 0.02), node positivity (33.3 vs. 55.0%; P = 0.01), and local recurrences (7.6 vs. 14.9% at 5 years; P = 0.0176). ConclusionsNT omission should be understood as a consequence of surgeon failure to perform local staging in most cases. Quality improvement efforts should focus on improving utilization of local staging.

Element Free Galerkin Post-processing Technique Based Error Estimator for Elasticity Problems

The study present a Mesh Free based post-processing technique for asymptotically (upper) bounded error estimator for Finite Element Analyses of elastic problems. The proposed technique uses Galerkin Element Free procedure for recovery of the displacement derivatives over a patch of nodes in radial domains. The radial nodes patches are used to construct the trial shape functions utilizing the moving least-squares (MLS) techniques. The proposed technique has been tested on three benchmark elastic problems discretized using 4-node quadrilateral elements. The recovered nodal stresses are utilized to calculate the error in finite element solution in energy norm. The study also demonstrates adaptive analysis application of proposed error estimator. The performance of proposed error estimator based on mesh independent node patches has been compared with that of mesh dependent node patches based Zienkiewicz-Zhu (ZZ) error estimator on structured and unstructured mesh. The improved results of the proposed error estimator in terms of convergence rate and effectivity are obtained. It is shown that present study incorporates the superiority of the Mesh Free Galerkin method into finite element analysis environment.

Radial perturbations of the scalarized Einstein-Gauss-Bonnet black holes

Recently a new class of scalarized black holes in Einstein-Gauss-Bonnet (EGB) theories was discovered. What is special for these black hole solutions is that the scalarization is not due to the presence of matter, but {it is induced} by the curvature of spacetime itself. Moreover, more than one branch of scalarized solutions can bifurcate from the Schwarzschild branch, and these scalarized branches are characterized by the number of nodes of the scalar field. The next step is to consider the linear stability of these solutions, which is particularly important due to the fact that the Schwarzschild black holes lose stability at the first point of bifurcation. Therefore we here study in detail the radial perturbations of the scalarized EGB black holes. The results show that all branches with a nontrivial scalar field with one or more nodes are unstable. The stability of the solutions on the fundamental branch, whose scalar field has no radial nodes, depends on the particular choice of the coupling function between the scalar field and the Gauss-Bonnet invariant. We consider two particular cases based on the previous studies of the background solutions. If this coupling has the form used in \cite{Doneva:2017bvd} the fundamental branch of solutions is stable, except for very small masses. In the case of a coupling function quadratic in the scalar field \cite{Silva:2017uqg}, though, the whole fundamental branch is unstable.

Toward the theory of the Yukawa potential

Using three different approaches Perturbation Theory (PT), the Lagrange Mesh Method (LMM), and the variational method, we study the low-lying states of the Yukawa potential. First orders of PT, in powers of the screening parameter, are calculated in the framework of the non-linearization procedure. It is found that the Padé approximants to PT series together with the LMM provide highly accurate values of energy and the positions of the radial nodes of the wave function. The most accurate results, at present, of the critical screening parameters for some low-lying states and the first coefficients in the expansion of the energy at the critical parameter are presented. A locally accurate and compact trial function for the eigenfunctions of the low-lying states is discovered. This function used as a zeroth order entry in PT leads to energies as precise as those of Padé approximants and LMM. Finally, a compact analytical expression for the energy, that reproduces at least 6 decimal digits in the entire physical range of the screening parameter, is found.

Information‐Entropic Measures in Confined Isotropic Harmonic Oscillator

AbstractInformation‐based uncertainty measures like Rényi entropy (R), Shannon entropy (S) and Onicescu energy (E) are employed to understand the influence of radial confinement in an isotropic harmonic oscillator (IHO). The transformation of the Hamiltonian into a dimensionless form gives an idea of the composite effect of oscillation frequency (ω) and confinement radius (). For a given quantum state, accurate results are provided by applying the respective exact analytical wave function in the r‐space. The p‐space wave functions are produced from Fourier transforms of radial functions. Pilot calculations are done taking order of entropic moments () as in r‐ and p‐spaces. A detailed, systematic analysis is performed for a 3D confined harmonic oscillator (CHO) with respect to state indices , and . It has been found that the CHO acts as a bridge between particles in a spherical box and the 3D free IHO. In the low‐ region, increases while decrease with the rise in . At moderate , there exists an interaction between two competing factors: i) radial confinement (localization) and ii) accumulation of radial nodes with growth of (delocalization). Most of these results are reported here for the first time, revealing many new interesting features.

Simulation Analysis of Temperature Field of Conical Friction Plate Based on Thermomechanical Coupling

Using ABAQUS software, the temperature field in the process of sliding friction of the dual steel plate of a new friction plate-conical friction plate was simulated and analyzed by the method of thermo-mechanical coupling. The distribution of heat flux density and the convective heat transfer on different surfaces of the dual steel were considered in the calculation. It is found that the highest temperature of the dual steel during sliding is inside the tapered groove. The temperature inside and outside of the tapered groove is distributed in a low-high-low state, that is, the temperature at the bottom of the tapered groove and the top of the groove is higher than the middle position The temperature gradient of the radial node gradually becomes larger with the passage of time; the temperature distribution of the entire dual steel plate shows a symmetrical trend.

The Gravitational Wave Signal from Core-collapse Supernovae

Abstract We study gravitational waves (GWs) from a set of 2D multigroup neutrino radiation hydrodynamic simulations of core-collapse supernovae (CCSNe). Our goal is to systematize the current knowledge about the post-bounce CCSN GW signal and recognize the templatable features that could be used by the ground-based laser interferometers. We demonstrate that, starting from ∼400 ms after core bounce, the dominant GW signal represents the fundamental quadrupole (l = 2) oscillation mode (f-mode) of the proto–neutron star (PNS), which can be accurately reproduced by a linear perturbation analysis of the angle-averaged PNS profile. Before that, in the time interval between ∼200 and ∼400 ms after bounce, the dominant mode has two radial nodes and represents a g-mode. We associate the high-frequency noise in the GW spectrograms above the main signal with p-modes, while below the dominant frequency there is a region with very little power. The collection of models presented here summarizes the dependence of the CCSN GW signal on the progenitor mass, equation of state, many-body corrections to the neutrino opacity, and rotation. Weak dependence of the dominant GW frequency on the progenitor mass motivates us to provide a simple fit for it as a function of time, which can be used as a prior when looking for CCSN candidates in the LIGO data.

Parametric design and static behavior analysis of single-layer hemi-ellipsoida latticed shell

The parametric design macro programs of two basic types of single-layer hemi-ellipsoidal latticed shell are developed by using APDL (Ansys Parametric Design Language) parameterized design language. The parametric design of single-layer hemi-ellipsoidal latticed shell structures can be built under the condition of giving the macroscopic geometric parameters such as specifical parameter t, parameter k, span S1, span S2, rise f, valley number Kn, radial node number Nx etc. Ansys software is applied to study comparison of characteristics of the Kewitte type net shell structure of different vector height f, radial node number Nx and boundary constraints. The results show that modeling design of hemi-ellipsoidal latticed shell can be built conveniently and quickly by the application of parametric design of macro program. The three-way grid type is more reasonable force performance, and it’s mechanical performance is better when the span ratio is 1/2. Thus it is suggested to give priority in the project.