Coulomb Constant Research Articles

Artificial electric field algorithm with repulsion mechanism

AbstractDue to its outstanding performance in addressing optimization problems, artificial electric field (AEF) algorithm has garnered increasing notice in recent years. Nevertheless, numerous studies indicate that AEF is susceptible to premature convergence when the region influenced by the global optimum constitutes a small fraction of the entire solution space. By conducting micro‐level research on the particles during the evolution process of AEF, it is revealed that the primary factors influencing optimization performance are the Coulomb's electrostatic force mechanism and the fixed attenuation factor. Inspired by this observation, we propose an improved version named artificial electric field algorithm with repulsion mechanism (RMAEF). Specifically, in RMAEF, a repulsion mechanism is incorporated to make particles escape from local optima. Furthermore, an adaptive attenuation factor is employed to update dynamically Coulomb's constant. RMAEF is compared with AEF and its state‐of‐art variants under 44 test functions from CEC 2005 and CEC 2014 test suites. From the experiment results, it is obvious that among 14 benchmark functions from CEC 2005 on 30D and 50D optimization, the RMAEF algorithm exhibits superior performance on 8 and 9 functions compared with advanced variants of AEF. For CEC 2014 on 30D and 50D optimization, the RMAEF algorithm produces the best results on 11 and 12 functions, respectively. In addition, three real‐world problems are also used to verify the versatility and robustness. The results demonstrate that RMAEF outperforms its competitors in terms of overall performance.

GraphT-T (V1.0Beta), a program for embedding and visualizing periodic graphs in 3D Euclidean space.

Following the work of Day & Hawthorne [Acta Cryst. (2022), A78, 212-233] and Day et al. [Acta Cryst. (2024), A80, 258-281], the program GraphT-T has been developed to embed graphical representations of observed and hypothetical chains of (SiO4)4- tetrahedra into 2D and 3D Euclidean space. During embedding, the distance between linked vertices (T-T distances) and the distance between unlinked vertices (T...T separations) in the resultant unit-distance graph are restrained to the average observed distance between linked Si tetrahedra (3.06±0.15 Å) and the minimum separation between unlinked vertices is restrained to be equal to or greater than the minimum distance between unlinked Si tetrahedra (3.713 Å) in silicate minerals. The notional interactions between vertices are described by a 3D spring-force algorithm in which the attractive forces between linked vertices behave according to Hooke's law and the repulsive forces between unlinked vertices behave according to Coulomb's law. Embedding parameters (i.e. spring coefficient, k, and Coulomb's constant, K) are iteratively refined during embedding to determine if it is possible to embed a given graph to produce a unit-distance graph with T-T distances and T...T separations that are compatible with the observed T-T distances and T...T separations in crystal structures. The resultant unit-distance graphs are denoted as compatible and may form crystal structures if and only if all distances between linked vertices (T-T distances) agree with the average observed distance between linked Si tetrahedra (3.06±0.15 Å) and the minimum separation between unlinked vertices is equal to or greater than the minimum distance between unlinked Si tetrahedra (3.713 Å) in silicate minerals. If the unit-distance graph does not satisfy these conditions, it is considered incompatible and the corresponding chain of tetrahedra is unlikely to form crystal structures. Using GraphT-T, Day et al. [Acta Cryst. (2024), A80, 258-281] have shown that several topological properties of chain graphs influence the flexibility (and rigidity) of the corresponding chains of Si tetrahedra and may explain why particular compatible chain arrangements (and the minerals in which they occur) are more common than others and/or why incompatible chain arrangements do not occur in crystals despite being topologically possible.

Connection Between Gravity and Quantum World

Gravity is the most important force in cosmology. A lot of research deals with it, but we only know its perceptible properties. Two basic descriptions of gravity are accepted today. One is based on classical physics based on Newton\’s theory. The other is the theory of gravity described by Einstein. However, another description of gravity is also possible. Gravitation can also be described in other ways using the equations of Kepler, Newton, Coulomb, and Maxwell. Using their equations, it can be deduced that: The magnitude of the gravitational force field is not determined only by mass. It depends on the speed of the mass. It depends on the size of the gravitational field in which the mass moves Newton\’s and Coulomb\’s laws are equivalent. This has already been determined by several researchers. It was also conducted by Constantin Meis. Newton\’s, Coulomb\’s, Maxwell\’s law can be used to determine a new cosmic constant. It can be counted on in the Solar System, but also in the Milky Way. Denote by μ_2 and √ (μ_2) This constant connects the macro world and the micro or quantum world. This constant can also be calculated using Coulomb\’s and Maxwell\’s equations Maxwell\’s and Coulomb\’s equation can be used to determine the resultant of the associated vibrating charges for each mass and celestial body. Coulomb\’s law can also be used to accurately determine the force effect between masses. Even the force effect between celestial bodies can be determined with it. This is exactly the same as the force effect calculated by Newton\’s law. For a mass of 1 kg, we get exactly Cavendish\’s measurement result with Coulomb\’s law. Already in the 20th century, it was suggested that there is a connection between gravity and the electromagnetic field. This has already been conducted by Constantin Meis and Takaaki Musha and B. Ivanov. Gravitational constant can not only be measured, but also calculated in several ways. This has already been determined by several researchers. The gravitational constant can also be calculated using the mass and its speed. But it can also be calculated using the Coulomb constant and μ_2 The gravitational force field for a given mass or celestial body can be calculated using √(μ_2) and the charge of the mass. The speed of a given planet can be calculated using its charge and √ (μ_2) Based on the derivations, gravity is a force field that has an electric force field component. Therefore, it can be the carrier medium of electromagnetic waves. And so is the carrier of light If we assume that the gravitational force field is a very high frequency electromagnetic wave, then we also understand that gravity is unipolar.

Failure criterion for concrete under volumetric stress state conditions

Based on the experiments conducted by the authors, a six-parameter failure criterion for concrete has been developed, which makes it possible to take into account the volumetric stress state in strength calculations of massive concrete and reinforced concrete structures. The developed strength criterion is adapted to a spatial eight-node finite element (solid type) and implemented in the PRINS software. To verify the developed criterion, the work provides a com-parison with both experimental data and calculation results that meet other strength criteria widely used for concrete. Thus, the compression and tension meridians of the developed fracture criterion were compared with experimental data, as well as with the Willam & Warnke criterion and the modified Drucker & Prager criterion with Mohr & Coulomb constants. A comparison of compression meridians shows that in the mode of low hydrostatic stresses , these criteria converge with each other and with experimental data. In the mode of average hydrostatic stresses , the criterion proposed by the authors and the Willam & Warnke criterion show similar results, while the modified Drucker & Prager criterion shows on 20% overestimation of the failure value. In the mode of high hydrostatic stresses , the Willam & Warnke criterion in com-parison with the proposed criterion and experimental data, gives an underestimated value of concrete failure.

First-Principles Comparative Study of CuFeSe2 and CuFeS2

In this paper, on the basis of first-principles, the CASTEP module of Materials Studio is used to calculate the band structures and optical properties of CuFeSe2 and CuFeS2 under the PBE pseudopotential of the generalized gradient approximation (GGA). The calculated results show that both CuFeSe2 and CuFeS2 are direct bandgap semiconductors with forbidden band widths of 0.64 eV and 1.06 eV, respectively. In the visible light range, the highest absorption coefficient of CuFeSe2 is 1.082×105 cm-1, the average reflectivity is 0.52, the maximum conductivity is 7.23 fs-1, the electrostatic constant is 65.9; the maximum value the highest absorption coefficient of CuFeS2 is 0.872×105 cm-1, the average reflectivity is 0.44, the maximum conductivity is 4.44 fs-1, the static dielectric constant is 52.32. The calculation results in this paper show that compared with CuFeS2, CuFeSe2 has advantages in photoconductivity and carrier separation, but has disadvantages in band gap and reflectivity. It is recommended to combine the two materials to prepare tandem solar cells.

Collective acoustic electronic excitations in LaH10 as a factor in boosting of the critical temperature of superconducting transition

The nearly room-temperature superconductivity that had been predicted theoretically for lanthanum and yttrium superhydrides at megabar pressures has been recently achieved experimentally in several superhydride compounds, including lanthanum decahydride with T _{c} of about 250 K under high pressure of about 150 GPa. Though superconductivity should be governed by the phonon mechanism in these compounds, which is evident due to the measured deuterium isotope effect in LaD10, we believe that the choice of small values of the effective Coulomb constant, used in theoretical calculations of the critical temperature, merits farther substantiation. We discuss the possibility for the collective acoustic electronic excitations (acoustic plasmons) to appear in the collective spectra of superhydrides thus facilitating the suppression of the Coulomb repulsion. In LaH10 the conditions for such mechanism arise due to the hybridization of La 4f and H 1s states near the Fermi level in the vicinity of the L-point of the Brillouin zone. A simple model approximation for the resulting conducting band allows us to show that in a certain portion of quasimomentum space an acoustic branch should appear in the spectrum of the collective electronic excitations in LaH10, arguably reducing the effective Coulomb constant.

Potential Simplification of Charge and the Coulomb Force without Affecting Predictions

We are taking a deeper look at charge and the Coulomb force and other electric properties. There is an embedded 10-7 in the Coulomb constant that we will claim is “only” needed to cancel out an embedded 107 in the charge squared. We suggest three alternatives to redefine the charge and the Coulomb constant that give considerable simplification. The Coulomb constant is not needed as a separate constant as, in the new suggested framework, it can be replaced with simply the speed of light without affecting predicted output values. We also point out potential issues with the 2019 redefinition of the Coulomb constant and elementary charge. This is not meant conclusive but to open up for further discussion on how one potential can simplify parts of physics.

Lattice gauge theory, gauge-gravity duality, and Coulomb constant in five dimensions

The purpose of this paper is to perform a quantitative check of gauge theory - gravity duality in a nonconformal, nonsupersymmetric context. In order to do so we define k5, an object extracted from the Wilson Loop, that plays the role of Coulomb's constant for SU(N) gauge theories in five dimensions and we argue that one of its virtues is that it could be minimally sensitive to N. This allows us to compute k5 on one hand from the gravitational backreation of a large number N of D4-branes, and on the other from a lattice mean-field expansion for N=2. We find a 2% numerical agreement between the two approaches.

Humic Ion-Binding Model VI: An Improved Description of the Interactions of Protons and Metal Ions with Humic Substances

Humic Ion-Binding Model VI, a discrete site/electrostatic model of the interactions of protons and metals with fulvic and humic acids, is applied to 19 sets of published data for proton binding, and 110 sets for metal binding. Proton binding is described with a site density, two median intrinsic equilibrium constants, two parameters defining the spread of equilibrium constants around the medians, and an electrostatic constant. Intrinsic equilibrium constants for metal binding are defined by two median constants, log KMA and log KMB, which refer to carboxyl and weaker-acid sites respectively, together with a parameter, ΔLK1, defining the spreads of values around the medians. A further parameter, ΔLK2, takes account of small numbers of strong binding sites. By considering results from many data sets, a universal average value of ΔLK1 is obtained, and a correlation established between log KMB and log KMA. In addition, a relation between ΔLK2 and the equilibrium constant for metal-NH3 complexation is tentatively suggested. As a result, metal-binding data can be fitted by the adjustment of a single parameter, log KMA. Values of log KMA are derived for 22 metal species. Model VI accounts for competition and ionic strength effects, and for proton-metal exchange.