No abstract

An approach guided by physical consistency in determining the general forms of D‐dimensional kinetic energy density functionals (KEDF) has been demonstrated previously, producing an expansion which contains the majority of the known one‐point KEDF forms. It has also been shown that any noninteracting KEDF must necessarily have a homogeneity degree of 2 in coordinate scaling, and that the ratio of the collective KED to electron density must approach the ionization energy as r→∞. This article demonstrates that the scaling condition is already satisfied in the general expansion despite not being conceived with the scaling as a constraint, and that the second condition places a restriction on the expansion terms of the KED. The discussion is extended as well for some known KEDs for comparison.

Within ``orbital-free'' density functional theory, it is essential to develop general kinetic energy density (KED), denoted as t(r). This is usually done by empirical corrections and enhancements, gradient expansions, machine learning, or axiomatic approaches to find forms that satisfy physical necessities. In all cases, it is crucial to determine the largest spatial density derivative order, $m$ in, t(r). There have been many efforts to do so, but none have proven general or conclusive and there is no clear guide on how to set m. In this work, we found that, by imposing KED finitude away from V(r) singularities. m=D+1 for systems of dimension D. This is consistent with observations and provides a needed guide for systematically developing more accurate semilocal KEDs.

Dust mitigation in photovoltaic panels has been a growing technological challenge as an increasing number of largescale solar cell installations are taking place in the desert environment and space to harness the abundant solar radiation effectively. The conventional methods of dust removal require a large quantity of water, complex mechanical instrumentation, enormous logistics, and manpower in the inhospitable and hostile desert environment. Many variants of electrodynamic dust shield (EDS) systems have been successfully tried for dust mitigation as this method involves low-cost installation and unmanned lowpower operation. In this work, we present the design and fabrication of a locally made three-phase electrodynamic dust repulsion system. The dust removal efficiency of the EDS system was optimized for the electrode geometry and the electrical parameters like AC source voltage and frequency. The dust removal efficiency as high as 92 ± 1% was observed for an optimum combination of geometrical and electrical parameters of the EDS. The operation and the optimization of the EDS system were elucidated by analyzing various electrostatic and mechanical forces and the generation of traveling waves involved in this process.The EDS system was applied on the solar cell under natural sunlight to study the efficacy of the system in improving the photovoltaic performance of the solar cell in the dusty environment. As the dust characteristics play an essential role in the dust removal efficiency, the morphological and elemental characterizations and dust particle size analysis of dust from a natural sandstorm were also conducted.

An approach guided by physical consistency in determining the general forms of D-dimensional kinetic energy density functionals (KEDF) has been demonstrated previously, producing an expansion which contains the majority of the known one-point KEDF forms. It is known that any noninteracting KEDF shall necessarily have a homogeneity degree of 2 in coordinate scaling. This paper demonstrates that this condition is already satisfied in the general expansion despite not being conceived with the scaling as a constraint.