Total Electric Charge Research Articles

Performance of density-functional-theory and random-phase-approximation methods on the study of transition-metal clusters: the Tan clusters as an example

Recently developed density-functional-theory (DFT) and random-phase-approximation (RPA) methods are used to study competing isomers of some negatively charged Ta clusters, namely Ta12 - and Ta10 -, in an attempt to find a suitable strategy towards accurate studies of transition-metal clusters based on DFT. Also the neutral and cationic forms Ta12 (0,+) of the twelve-atom cluster are studied. The results are compared with experimental information obtained by several methods that differ in the property under study and the total electric charge of the clusters. We find that a careful choice of the density functional, the use of relativistic two-component methods, eventually in combination with all-electron basis sets, and the application of RPA-type methods, may all be necessary steps for a good assessment. Such an assessment should be made in relation to several experimental properties as much as possible.

Establishing industrial Zn‑Ni brush electroplating process without post-plating hydrogen embrittlement relief baking

Transitioning from carcinogenic cadmium (Cd) to zinc‑nickel (Zn‑Ni) coating in aircraft components to prevent corrosion poses a challenge of hydrogen embrittlement (HE) of the substrate. While post-plating baking addresses HE in Zn‑Ni coated components, the economic repair of damaged coatings using the Zn‑Ni brush plating process without baking remains problematic. Therefore, in this work, the HE susceptibility of Zn‑Ni brush electroplating, both with and without baking has been investigated by subjecting plated notched specimens to a sustained load test (SLT) in accordance with ASTM F519. Baked specimens after plating passed the SLT, while unbaked specimens exhibit severe HE and fail. Adjusting electroplating parameters alone, such as plating current density and total plating electric charge, did not reduce HE vulnerability of the Zn‑Ni brush plating process without baking. However, optimizing the pre-plating grit blasting process (pressure, working distance), along with reducing the total plating electric charge, and introducing a 72 h delay between electroplating and subsequent SLT, enable plated specimens to exhibit no HE and to pass SLT without requiring baking.

Effect of anode material and dispersal limitation on the performance and biofilm community in microbial electrolysis cells

In a microbial electrolysis cell (MEC), the oxidization of organic compounds is facilitated by an electrogenic biofilm on the anode surface. The biofilm community composition determines the function of the system. Both deterministic and stochastic factors affect the community, but the relative importance of different factors is poorly understood. Anode material is a deterministic factor as materials with different properties may select for different microorganisms. Ecological drift is a stochastic factor, which is amplified by dispersal limitation between communities. Here, we compared the effects of three anode materials (graphene, carbon cloth, and nickel) with the effect of dispersal limitation on the function and biofilm community assembly. Twelve MECs were operated for 56 days in four hydraulically connected loops and shotgun metagenomic sequencing was used to analyse the microbial community composition on the anode surfaces at the end of the experiment. The anode material was the most important factor affecting the performance of the MECs, explaining 54–80 % of the variance observed in peak current density, total electric charge generation, and start-up lag time, while dispersal limitation explained 10–16 % of the variance. Carbon cloth anodes had the highest current generation and shortest lag time. However, dispersal limitation was the most important factor affecting microbial community structure, explaining 61–98 % of the variance in community diversity, evenness, and the relative abundance of the most abundant taxa, while anode material explained 0–20 % of the variance. The biofilms contained nine Desulfobacterota metagenome-assembled genomes (MAGs), which made up 64–89 % of the communities and were likely responsible for electricity generation in the MECs. Different MAGs dominated in different MECs. Particularly two different genotypes related to Geobacter benzoatilyticus competed for dominance on the anodes and reached relative abundances up to 83 %. The winning genotype was the same in all MECs that were hydraulically connected irrespective of anode material used.

Observational appearance of Kaluza–Klein black holes

The optical properties of rotating black holes in Kaluza–Klein theory described by the total mass, spin, and electric and magnetic charges are investigated in detail. Using a developed general relativistic ray-tracing code to calculate the motion of photons, shadows of Kaluza–Klein black holes are generated. The properties of the shadow and the light deflection angle around these black holes are also studied in order to put constraints on the parameters of Kaluza–Klein black holes using M87* shadow observations. The possibility of imposing constraints on Kaluza–Klein black holes using shadow observations is investigated. Moreover, we find that small charges (electric and magnetic) of the black hole can meet these constraints. We conclude that with the current precision of the M87* black hole shadow image observation by the EHT collaboration, the shadow observations of Kaluza–Klein black holes are indistinguishable from that of the Kerr black hole. Much better observational accuracy than the current capabilities of the EHT collaboration are required in order to place verified constraints on the parameters of modified theories of gravity in the strong field regime.

The size-dependent frictionless contact of piezoelectric materials

According to the couple-stress theory, the size-dependent frictionless contact problem between a transversely isotropic piezoelectric half-plane and a rigid conducting or insulating punch is examined in this paper. With the purpose of describing size effect appearing in material microstructures, the couple-stress theory introduces the characteristic length parameter in the constitutive equations. Using Fourier transform method, frictionless contact problems of flat and cylindrical punches are simplified to Cauchy singular integral equations. In order to determine the electric charge density and normal pressure, these equations are numerically solved by transforming into algebraic ones. The influences of size parameter and total electric charge on the electric charge density, in-plane electric displacement, in-plane stress, and contact pressure are predicted. Results for the surface electromechanical fields forecasted by the couple-stress theory depart significantly from the classical results.

On the Electromagnetic Radiation Associated with Zero and First Modes of a Droplet Oscillating in an External Electrostatic Field

The paper deals with electromagnetic radiation generated by capillary oscillations of the zero and first modes of oscillations of a droplet in an external electrostatic field. It is assumed that the droplet of an ideal incompressible electrically conductive liquid has a zero total electric charge and that it is charged in an external uniform electrostatic field by induced charges of opposite signs. The radiation under discussion is detected via analytical asymptotic calculations of the second order infinitesimal by the dimensionless amplitude of the droplet oscillations in an external electrostatic field. An analytical expression was found for the intensity of the electromagnetic radiation associated with oscillations of the zero and first modes, and the dependence of the intensity of radiation on the value of the field strength, the droplet size, and the value of the surface tension coefficient.

Semi-analytic model for plasma production and Cherenkov radiation emission from hypervelocity impacts on soda–lime glass

A semi-analytic method is proposed to compute the produced plasma and the emitted Cherenkov radiation from hypervelocity impacts on soda–lime glass for various projectiles and impact velocities. First, the Taylor–von Neumann–Sedov blast wave model, coupled with the system of nonlinear Saha equations for multispecies, strongly coupled plasma, is adopted to estimate the hydrodynamic profiles and the ionization state of the target material in the early stage of the impact. Second, the Frank–Tamm formula is considered to investigate the onset of the Cherenkov radiation and to compute the emitted energy. The present approach predicts a linear dependence of the produced total electric charge on the projectile density and a quadratic dependence on the projectile velocity, whereas the emitted Cherenkov radiation scales quadratically with the produced charge if the onset conditions are met.

An Ant Colony Optimization Behavior-Based MOEA/D for Distributed Heterogeneous Hybrid Flow Shop Scheduling Problem Under Nonidentical Time-of-Use Electricity Tariffs

This article studies a distributed heterogeneous hybrid flow shop scheduling problem under nonidentical time-of-use electricity tariffs (DHHFSP-NTOU). The makespan and the total electricity charge are considered as the optimization objectives from the view of production and management. The DHHFSP-NTOU considers different processing capabilitie and time-of-use electricity tariffs for each factory. The mixed-integer linear programming (MILP) model of DHHFSP-NTOU is established. To solve the DHHFSP-NTOU, this article proposes an ant colony optimization behavior-based multiobjective evolutionary algorithm based on decomposition (ACO_MOEA/D). A problem-specific ant colony behavior is presented to construct offspring individuals. Eight neighborhoods within the factory and between factories are adopted to improve the quality of the individuals in the archive set. A right-shift movement is used to reduce the electricity charge. A large number of numerical experiments and comprehensive investigations are carried out to test the efficiency and effectiveness of ACO_MOEA/D. The experimental results show that each component (e.g., ant colony behavior, neighborhoods move operators, right-shift movement) contributes to the performance of ACO_MOEA/D. The comparisons with several related algorithms show the superiority of ACO_MOEA/D for solving the DHHFSP-NTOU. Note to Practitioners—From the managers’ insights, the electricity charge is a large cost in the production. The scheduling is an economical approach to reduce the electricity charge. For the time-of-use (TOU) tariffs, the managers can adjust the schedule to reduce the idle time or move some operations to the interval period with a lower electric price. This article studies a distributed heterogeneous hybrid flow shop scheduling problem under nonidentical TOU (UTOU) electricity. This model can be used in many manufacturing enterprises that have several heterogeneous factories. This article proposes an ant colony optimization behavior-based multiobjective evolutionary algorithm based on decomposition (ACO_MOEA/D) to minimize the makespan and the total electricity charge. The ACO_MOEA/D can provide the economy and high-efficiency schedules for practitioners. The computational results confirm its effectiveness and efficiency.

ФОРМУВАННЯ БІПОЛЯРНИХ ІМПУЛЬСНИХ СТРУМІВ У НАВАНТАЖЕННІ ЄМНІСНИХ НАКОПИЧУВАЧІВ ЕНЕРГІЇ ЕЛЕКТРОРОЗРЯДНИХ УСТАНОВОК

A method is proposed for stabilizing the transient discharge processes of capacitive energy storages (CESs) of electric discharge installations (EDIs) to a load whose electrical resistance can vary non-linearly and stochastically. The method is based on the use of one direct voltage generator (DVG) in the EDI, which carries out alternately an oscillatory charge of two CESs to the required voltage, as well as on the introduction of semiconductor switches into the charge circuit and discharge one of these CESs and the developed algorithms for switching them on, according to which bipolar discharge currents are formed alternately in the EDI load, regardless of the nature of the change in its electrical resistance. The frequency and duration of positive and negative discharge-pulse currents in the load can be the same or different, depending on the selected parameters of the elements of discharge circuits of the two CESs. The use of the developed method provides the formation of unipolar modes in the capacitors of each CES, which allows you to choose them for lower voltages, increase their life and reduce cost. In addition, with the same capacitance of the CESs, the total electric charge flowing in the load is practically zero after each even number of discharges. This significantly reduces the effect of electrochemical processes in the load, in particular the electrochemical destruction of the anode of the technological apparatus of the EDI, which inevitably occurs during the formation of unipolar pulse currents. The use of bipolar discharge currents in the EDI load also increases the stability of the discharge modes in the EDI due to the limitation of the duration of possible long aperiodic currents during the discharge of one of the CESs by the beginning of the counter current of the next discharge of the other CES. References 10, figures 3, table 1.

Self-dual CP(2) vortex-like solitons in the presence of magnetic impurities

We investigate the existence of vortex configurations in two gauged-$CP(2)$ models extended via the inclusion of magnetic impurities. In particular, we consider both the Maxwell-$CP(2)$ and the Chern-Simons-$CP(2)$ enlarged scenarios, separately. We choose a $CP(2)$-field configuration with a null topological charge not only in the simplest (free) case, but also when coupled to an Abelian gauge field. The implementation of the Bogomol'nyi-Prasad-Sommerfield (BPS) formalism shows that the effective models for such a configuration possess a self-dual structure which looks like those inherent to the gauged sigma models. Therefore, when the $CP(2)$ field is coupled to the Maxwell term, the corresponding total energy possesses both a well-defined Bogomol'nyi bound and a quantized magnetic flux. Further, when the $CP(2)$ scenario is gauged with the Chern-Simons action, the total electric charge is verified to be proportional to the quantized magnetic flux. In addition, the analysis verifies that the magnetic impurity contributes to the BPS potentials and appears in both of the models' BPS equations. Next, we introduce a Gaussian-type impurity and solve the self-dual equations via a finite-difference scheme. The resulting solutions present a nonmonotonic behavior that flips both the magnetic and electric fields. Finally, we discuss the topologically trivial solutions in the limit for which the impurity becomes a Dirac $\ensuremath{\delta}$ function.

Symplectic Hamiltonian finite element methods for electromagnetics

We present several high-order accurate finite element methods for the Maxwell’s equations which provide time-invariant, non-drifting approximations to the total electric and magnetic charges, and to the total energy. We devise these methods by taking advantage of the Hamiltonian structures of the Maxwell’s equations as follows. First, we introduce spatial discretizations of the Maxwell’s equations using mixed finite element, discontinuous Galerkin, and hybridizable discontinuous Galerkin methods to obtain a semi-discrete system of equations which display discrete versions of the Hamiltonian structure of the Maxwell’s equations. Then we discretize the resulting semi-discrete system in time by using a symplectic integrator. This ensures the conservation properties of the fully discrete system of equations. For the Symplectic Hamiltonian HDG method, we present numerical experiments which confirm its optimal orders of convergence for all variables and its conservation properties for the total linear and angular momenta, as well as the total energy. Finally, we discuss the extension of our results to other boundary conditions and to numerical schemes defined by different weak formulations.

Subcutaneous Stimulation as Add-on Therapy to Spinal Cord Stimulation in Patients With Persistent Spinal Pain Syndrome Significantly Increases the Total Electrical Charge per Second: Aspects on Stimulation Parameters and Energy Requirements of the Implanted Neurostimulators

ObjectiveIn our previous multicenter randomized controlled trial, we demonstrated the clinical effectiveness of peripheral nerve field stimulation (PNFS) as add-on therapy to spinal cord stimulation (SCS) for the treatment of chronic back pain in patients with persistent spinal pain syndrome (PSPS) or failed back surgery syndrome (FBSS). To our knowledge, no previous study has investigated the effect of PNFS as an add-on to SCS on the energy consumption of the implanted neurostimulators. Therefore, in this study, we compared the specific stimulation parameters and energy requirements of a previously unreported group of patients with only SCS with those of a group of patients with SCS and add-on PNFS. We also investigated differences that might explain the need for PNFS in the treatment of chronic low back pain. Materials and MethodsWe analyzed 75 patients with complete sets of stimulation parameters, with 21 patients in the SCS-only group and 54 patients in the SCS + PNFS group. Outcome measures were average visual analog scale score, SCS parameters (voltage, frequency, and pulse width), SCS charge per second, and total charge per second. We analyzed baseline characteristics and differences between and within groups over time. ResultsBoth groups had comparable patient characteristics at baseline and showed a significant decrease in back and leg pain. SCS charge per second did not significantly differ between the groups at baseline or at 12 months. The total charge per second was significantly higher in the active SCS + PNFS group than in the SCS-only group at baseline; in the SCS + PNFS group, this persisted for up to 12 months, and the SCS charge per second and total charge per second increased significantly over time. ConclusionsOur results show that add-on PNFS increases the total charge per second compared with SCS alone, as expected. However, further research is needed because our results do not directly explain why some patients require add-on PNFS to treat low back pain.

Extremal isolated horizons with a cosmological constant and the related unique type D black holes

We extend our previous work in which we derived the most general form of an induced metric describing the geometry of an axially symmetric extremal isolated horizon (EIH) in asymptotically flat spacetime. Here we generalize it to EIHs in asymptotically (anti-)de Sitter spacetime. The resulting metric conveniently forms a 6-parameter family which, in addition to a cosmological constant $\Lambda$, depends on the area of the horizon, total electric and magnetic charges, and two deficit angles representing conical singularities at poles. Such a metric is consistent with results obtained in the context of near-horizon geometries. Moreover, we study extremal horizons of all black holes within the class of Plebanski-Demianski exact (electro)vacuum spacetimes of the algebraic type D. In an important special case of non-accelerating black holes, that is the famous Kerr-Newman-NUT-(A)dS metric, we were able to identify the corresponding extremal horizons, including their position and geometry, and find explicit relations between the physical parameters of the metric and the geometrical parameters of the EIHs.

Electrically charged supermassive twin stars

By assuming that ultra dense hybrid neutron stars are endowed with a distribution of electric charge, we study the corresponding twin star solutions and their properties resulting from a sharp first order transition from confined hadronic to a deconfined quark phase. Two distinct quark matter equations of state with increasing stiffness are considered and the values for the maximum gravitational masses of the hadronic and hybrid twin configurations are obtained for different values of the total electric charge. Interestingly, our calculations indicate that sharp transitions make charged twin hybrid stars more massive than their neutral counterparts, and that the {2},{hbox {M}_{odot }} constraint from PSR J0740+6620 is surpassed for standard values of electric charge and can be considered stable only satisfying partial M/partial epsilon _0 > 0. In particular, our charged stellar models reach masses even higher than the unknown compact object measured in the GW190814 event.

Geometrical Polarization Approach method applied to A(B’B″)O3 complex perovskites

The geometric polarization approach (GPA) method is proposed to obtain the intrinsic polarization of polar dielectrics with complex A(B’B″)O3 perovskite structure. The aspects related to the aliovalent site occupation (B′,B″) in this kind of complex perovskites are presented, discussed and analyzed aiming at its application in GPA. The GPA method is applied to determine the intrinsic polarization of Pb(Zr0.6Ti0.4)O3 (PZT60/40, rhombohedral, R3m space group) and Pb(Zr0.4Ti0.6)O3 (PZT40/60, tetragonal, P4mm) compounds at room temperature as prototype phases of polar dielectrics with complex A(B’B″)O3 perovskite structure. The intrinsic polarizations, 49 μC/cm2 and 45 μC/cm2 for PZT60/40 and PZT40/60 compounds, respectively, as signatures of the polar state and in complete agreement with previous reports, are obtained from the off-centering position of the total negative and positive electric charges at the unit cell.

The Concept of Particle-Antiparticle and the Baryon Asymmetry of the Universe

Following the results of our publications, in the first part of this letter, we explain that quantum theory based on finite mathematics (FQT) is more general (fundamental) than standard quantum theory based on Poincare invariance. Standard concept of particle-antiparticle is not universal because it arises as a result of symmetry breaking from FQT to standard quantum theory based on Poincare or standard anti-de Sitter symmetries. In FQT one irreducible representation of the symmetry algebra describes a particle and its antiparticle simultaneously, and there are no conservation laws of electric charge and baryon quantum number. Poincare and standard anti-de Sitter symmetry are good approximations at the present stage of the universe but in the early stages they cannot take place. Therefore, the statement that in such stages the numbers of baryons and antibaryons were the same, does not have a physical meaning, and the problem of baryon asymmetry of the universe does not arise. Analogously, the numbers of positive and negative electric charges at the present stage of the universe should not be the same, i.e., the total electric charge of the universe should not be zero.

아파트의 전기서비스 요금 분배에 관한 시뮬레이션 연구

초록·키워드 목차 오류제보하기 Apartment complexes are the most common type of housing in Korean urban areas. In the single ("Danil") contract system, which is the most widely adopted electricity rate system in apartments in Korea, the total electricity charge for a whole apartment complex is calculated based on the average consumption per household by adding up the usage in common areas. Then, the total electricity charge is distributed to each household. From the current distribution method, this paper identifies abnormal distribution results through simulation studies. It is confirmed that the amount paid by each household is affected by the consumptions of other households. The results confirm that the current single (“Danil”) contract system violates the "Beneficiary pays principle", which is a primary principle for service fairness. #Electricity Bill #Single (“Danil”) Contract #Simulation #Scenario Analysis #Sensitivity Analysis AbstractⅠ. 서론Ⅱ. 문헌 연구Ⅲ. 시뮬레이션 연구Ⅳ. 결론참고문헌

Electrically charged compact stars with an interacting quark equation of state

We investigate the properties of non-rotating, electrically charged strange quark stars in four-dimensional Einstein–Maxwell theory. For quark matter we adopt the well-motivated quantum chromodynamics (QCD) equation-of-state, while for the charge density we assume it is proportional to the mass density. The system of coupled structure equations are integrated numerically, and we compute the mass, the radius as well as the total electric charge of the stars. Moreover, we perform a detailed numerical study of the effect of electric charge using the interacting quark equation-of-state. We find that stars as heavy as two solar masses can be supported, and that the highest radius and highest mass of the stars increase with the charge density.

Structural properties of charged compact stars with color-flavor-locked quarks matter

The observations of pulsars with masses close to [Formula: see text] have put strong constraints on the equation-of-state (EoS) of neutron-rich matter at supranuclear densities. Moreover, the exact internal composition of those objects is largely unknown to us. Aiming to reach the [Formula: see text] limit, here we investigate the impact of electric charge on properties of compact stars assuming that the charge distribution is proportional to the mass density. The study is carried out by solving the Tolman–Oppenheimer–Volkoff (TOV) equation for a well-motivated exotic quark matter in the color-flavor-locked (CFL) phase of color superconductivity. The existence of the CFL phase may be the true ground state of hadronic matter with the possibility of the existence of a pure stable quark star (QS). Concerning the equation-of-state, we obtain structural properties of quark stars and compute the mass, the radius as well as the total electric charge of the star. We analyze the dependence of the physical properties of these QSs depending on the free parameters with special attention on mass–radius relation. We also briefly discuss the mass versus central mass density [Formula: see text] relation for stability, the effect of electric charge and compactness. Finally, our results are compared with the recent observations data on mass–radius relationship.

Uniqueness of extremal isolated horizons and their identification with horizons of all type D black holes* *This work is dedicated to the memory of our late colleague Dr. Martin Scholtz (1984–2019), the supervisor of DM unfortunately, due to the formal reasons he cannot be listed as its co-author.

We systematically investigate axisymmetric extremal isolated horizons (EIHs) defined by vanishing surface gravity, corresponding to zero temperature. In the first part, using the Newman–Penrose and GHP formalism we derive the most general metric function for such EIHs in the Einstein–Maxwell theory, which complements the previous result of Lewandowski and Pawlowski. We prove that it depends on 5 independent parameters, namely deficit angles on the north and south poles of a spherical-like section of the horizon, its radius (area), and total electric and magnetic charges of the black hole. The deficit angles and both charges can be separately set to zero. In the second part of our paper, we identify this general axially symmetric solution for EIH with extremal horizons in exact electrovacuum Plebański–Demiański spacetimes, using the convenient parameterization of this family by Griffiths and Podolský. They represent all (double aligned) black holes of algebraic type D without a cosmological constant. Apart from a conicity, they depend on 6 physical parameters (mass, Kerr-like rotation, NUT parameter, acceleration, electric and magnetic charges) constrained by the extremality condition. We were able to determine their relation to the EIH geometrical parameters. This explicit identification of type D extremal black holes with a unique form of EIH includes several interesting subclasses, such as accelerating extremely charged Reissner–Nordström black hole (C-metric), extremal accelerating Kerr–Newman, accelerating Kerr–NUT, or non-accelerating Kerr–Newman–NUT black holes.