Analytical Energy Research Articles

Improved Analytic Energy Operator and Novel Three-Spectral Line Interpolation DFT Method for Parameter Estimation of Voltage Flicker

An improved analytical energy operator(IAEO) and novel three-spectral line interpolation discrete Fourier method is proposed in this paper to estimate voltage flicker parameter. Firstly, the analytic energy operator is improved based on Taylor series to better extract the amplitude and frequency features of voltage flicker envelope signal, and simplify the envelope extraction formula to avoid the square root operation. Then, a novel three-spectral line interpolation DFT algorithm is constructed by using Kaiser window and Blackman-Harris mutual convolution, and the amplitude and frequency correction formulas of voltage flicker are derived based on the novel three-spectral line interpolation DFT. Finally, the voltage flicker parameter estimation is realized on the virtual instrument based on the proposed method. The applicability and accuracy of the IAEO and novel three-spectral line interpolation DFT method for parameter estimation of voltage flicker are verified by a series of simulations and experiments.

Large-Signal Stability Analysis of AC Micro-Grid Under Quadratic Droop Control

Quadratic droop control is an innovative control strategy for power network, aiming to respect the inherently quadratic nature of reactive power flow. However, the system stability under quadratic droop control has not been addressed completely so far. This paper mainly focuses on the large-signal stability analysis of the AC network under quadratic droop control. We firstly analyze the stability of each equilibrium, it is concluded that the high-voltage equilibrium is stable as long as it exists while all low-voltage equilibria are unstable. Secondly, an analytical energy function for the system under quadratic droop control is established. It is proved that the high-voltage equilibrium is the local minimum of the proposed energy function while all the low-voltage equilibria are saddle points. Thirdly, to estimate the region of attraction (ROA) of the high-voltage equilibrium, an innovative method based on the analytical energy function is proposed. Comparing with the closest UEP method, the proposed ROA method significantly reduce the amount of computations. Simulation results verify the proposed theorems.

Phase and defect diagrams based on spectral grain boundary segregation: A regular solution approach

Recent works have proposed the treatment of alloy defect states with thermodynamics analogous to phase thermodynamics, so they can be analyzed in a manner that is comparable to bulk phase diagrams. We refer to such diagrams containing both bulk phase and defect state information as “phase-and-defect diagrams.” Segregated grain boundaries (GBs) are an example of one such defect state, which enable, for example, the stabilization of nanocrystalline alloys. The recent development of spectral thermodynamic isotherms has demonstrated that a fully spectral description, which captures the complete distribution of local atomic environments in the grain boundary network, is necessary for accurate modeling of segregation behavior. To our knowledge, there is currently no spectral free energy formulation from which a phase-and-defect diagram of the segregated polycrystalline state can be produced. In this work, we present a spectral regular solution model of grain boundary segregation, from which we derive an analytical free energy function for the segregated polycrystalline state. We then use this free energy representation to construct a phase-and-defect diagram for a hypothetical alloy system, providing a framework for future efforts in developing spectral phase-and-defect diagrams.

Exact analytical quasibound states of a scalar particle around a Reissner-Nordström black hole

In this paper, we investigate behavior of massive and massless scalar particle around a static spherically symmetric charged black hole—so called Reissner-Nordström black hole in 3+1 dimension. We successfully discover a novel exact analytical quasibound states' wave functions and energy levels by solving the covariant Klein-Gordon wave equation. The quasibound state has complex-valued energy E=ER+iEI where the real part ER can be interpreted as the scalar particle's energy while the imaginary part represents the decay. We also discuss the Hawking radiation from the apparent horizon of Reissner-Nordström black hole which can be calculated using the scalar particle's wave function. In principle, this study could provide the possibility for laboratory testing of effects whose nature is absolutely related with quantum effects in gravity.

Constraining an eddy energy dissipation rate due to relative wind stress for use in energy budget-based eddy parameterisations

Abstract. A geostrophic eddy energy dissipation rate due to the interaction of the large-scale wind field and mesoscale ocean currents, or relative wind stress, is derived here for use in eddy energy budget-based eddy parameterisations. We begin this work by analytically deriving a relative wind stress damping term and a baroclinic geostrophic eddy energy equation. The time evolution of this analytical eddy energy in response to relative wind stress damping is compared directly with a baroclinic eddy in a general circulation model for both anticyclones and cyclones. The dissipation of eddy energy is comparable between each model and eddy type, although the numerical model diverges from the analytical model at around day 150, likely due to the presence of non-linear baroclinic processes. A constrained dissipation rate due to relative wind stress is then proposed using terms from the analytical eddy energy budget. This dissipation rate depends on the potential energy of the eddy thermocline displacement, which also depends on eddy length scale. Using an array of ocean datasets, and computing two forms for the eddy length scale, a range of values for the dissipation rate are presented. The analytical dissipation rate is found to vary from 0.25 to 4 times that of a constant dissipation rate employed in previous studies. The dissipation rates are generally enhanced in the Southern Ocean but smaller in the western boundaries. This proposed dissipation rate offers a tool to parameterise the damping of total eddy energy in coarse resolution global climate models and may have implications for a wide range of climate processes.

Modeling of multi-material beams in analytical SEA

This study presents a method for predicting vibrations in multi-material, multi-layer beams using Analytical Statistical Energy Analysis (ASEA) by considering them as homogeneous beams with equivalent bending characteristics. This approach enables the simultaneous achievement of weight reduction and noise and vibration performance, which is essential in the current trend of using lightweight materials such as high strength steel, aluminum, and fiber-reinforced plastics in vehicle body structures. The proposed method is validated through Finite Element Method (FEM) calculation and the vibration energy transfer characteristics of multi-layer beams are examined. Additionally, an example of replacing a steel single-unit beam with a multi-layer beam is presented to demonstrate the potential of the proposed method in achieving lightweight and low vibration.

Dynamics analysis of spur gears considering random surface roughness with improved gear body stiffness

In previous calculation of gear mesh stiffness, the gear body is typically treated as a deformable elastic ring, and the stiffness of the gear body is determined using Sainsot's empirical formula. In this paper, a new calculation method for determining the gear body stiffness based on the analytical finite element-potential energy method is proposed, and its feasibility is verified by the finite element method. A new nonlinear dynamic model for a spur gear system is established, taking into account the time-varying backlash and random surface roughness. This model aims to investigate the dynamical responses of the gear system under various parameters, including rotational speed, shaft hole radius and surface roughness. The results indicate that the proposed method for calculating the stiffness of the gear body is significantly more accurate than Sainsot's empirical formula, as it closely aligns with the finite element method. This leads to a more precise calculation of the time-varying mesh stiffness. The gear dynamics model incorporating random surface roughness exhibits a heightened degree of realism and complexity in its dynamic phenomena. This study provides a valuable reference for the future development of dynamic gear systems.

LEAF + AIO: Edge-Assisted Energy-Aware Object Detection for Mobile Augmented Reality

Today very few deep learning-based mobile augmented reality (MAR) applications are applied in mobile devices because they are significantly energy-guzzling. In this paper, we design an edge-based energy-aware MAR system that enables MAR devices to dynamically change their configurations, such as CPU frequency, computation model size, and image offloading frequency based on user preferences, camera sampling rates, and available radio resources. Our proposed dynamic MAR configuration adaptations can minimize the per frame energy consumption of multiple MAR clients without degrading their preferred MAR performance metrics, such as latency and detection accuracy. To thoroughly analyze the interactions among MAR configurations, user preferences, camera sampling rate, and energy consumption, we propose, to the best of our knowledge, the first comprehensive analytical energy model for MAR devices. Based on the proposed analytical model, we design a LEAF optimization algorithm to guide the MAR configuration adaptation and server radio resource allocation. An image offloading frequency orchestrator, AIO, coordinating with the LEAF, is developed to adaptively regulate the edge-based object detection invocations and to further improve the energy efficiency of MAR devices. Extensive evaluations are conducted to validate the performance of the proposed analytical model and algorithms.

EVALUATION OF ENERGY-COST-EFFICIENT DESIGN ALTERNATIVES FOR RESIDENTIAL BUILDINGS IN KARNATAKA’S TROPICAL WET AND DRY CLIMATIC ZONES

Introduction: The existing building construction techniques in India account for increased operating energy consumption. Due to this, there is a need to apply sustainable construction methods by including passive design techniques. In accordance with the local climatic condition, a good passive design not only maintains a comfortable environment in the house, but also consumes less energy all the while performing the same basic functions as the traditional structures. Purpose of the study: The present research focuses on residential villas by analyzing parameters such as illuminance, energy, and cost consumption using Revit (Insight 360) software with two different cases. Methods: Considering Case1 as an existing villa of conventional design and Case2 presenting a proposed villa, a remodeling of the existing villa with an increased window wall ratio (WWR), different fenestration designs, and a new building plan. The authors followed the Indian Green Building Council (IGBC) guidelines relating to illuminance and generated an analytical energy model using Insight 360 to compare the energy consumption and cost efficiency of the cases. Results: The effectiveness of various fenestration types related to direct heat gain, window orientation that would provide more natural light, total operating energy consumption and costs of two different cases of villas are investigated in this paper.

Spectral properties and exact solutions for Rabi-coupled noninteracting fermions in a spin-dependent anharmonic trapping potential

We investigate the effect of spin-motion coupling on the spectral properties of Rabi-coupled noninteracting fermions in a spin-dependent harmonic trapping potential plus an anharmonic term. It is shown that when the spin-motion coupling becomes strong, fermions tend to stay in one of the two components. In the limit of the strong spin-motion coupling, the entire energy spectrum exhibits a sequence of near degeneracy. In particular, in the case of the sextic anharmonic term, the system admits the exact analytical energies and wave functions of the bound states for an infinite number of the specific parameter conditions. The properties of the energy spectrum have also been discussed on basis of these obtained exact analytical solutions.

Efficient removal of Cr (VI) from aqueous solution using memory effect property of layered double hydroxide material

Treating wastewater containing pollutants with layered double hydroxide (LDH) material attracts excellent interest. LDH materials are known by the memory effect property, which leads to the reconstruction of the LDH structure after its calcination and rehydration. In this study, LDH material was prepared, calcined, and then rehydrated in an aqueous Cr(VI) solution. XRD, FTIR, and SEM-EDS analysis confirm the successful reconstruction of LDH-loading chromium on its surface and layered space. Response surface methodology (RSM) results showed that LDH mass, contact time, and chromium concentration are the main factors controlling the removal of Cr(VI). The heterogeneous sorption of chromium was described by fitting the equilibrium data to the Freundlich model. Analytical techniques, thermodynamic data, activation, and adsorption energies confirm that the removal process of Cr(VI) is endothermic, spontaneous, and physical nature. LDH exhibits good reusability performance with only a 7% reduction of initial adsorption capacity after five cycles of the calcination-rehydration process. These results show that the memory effect of LDH is helpful for the intercalation and the removal of emergent pollutants, especially for wastewater treatment.

Learning-Based personal models for joint optimization of thermal comfort and energy consumption in flexible workplaces

Due to distinct preferences across individuals, a large proportion of people are not satisfied with the thermal environments of their workplaces. Although recent studies have investigated flexible workplaces to meet the different preferences of individuals, the feasibility of adopting them to real-world environments is limited by the room capacity and potential for extra energy consumption. To address the knowledge gaps, this paper proposes a framework to jointly optimize thermal comfort and energy consumption of buildings through flexible workplaces by considering personal thermal preferences. A joint optimization algorithm that integrates building energy and personal thermal comfort models is developed based on the concept of the Large Neighborhood Search (LNS) algorithm. Analytical energy prediction models are obtained through Nonlinear Polynomial Regression (NPR) and personal thermal comfort models are established using Support Vector Machine Models (SVM). To verify the algorithm, a case study considering two scenarios (with and without existing personal thermal comfort data) is presented. The results indicate the proposed optimization algorithm can significantly improve the thermal comfort of the occupants while saving 22% and 14 % of energy consumption in the two scenarios, respectively. The proposed optimization method is valuable for building managers while adopting the concept of flexible workplaces.

Uniform magnetic field on the relativistic spinless particles with constant rest mass in 2D polar space

We present a model for the interaction of relativistic spin-0 charged particles moving in a uniform magnetic field. In the absence of an improved perturbative approach, we solve Kummer's differential equation directly, including principal quantum numbers. As a functional approach to nuclear interaction, we consider relativistic particle bound states subject to a interaction without an antiparticle regime. Within the approximation line to , we have also improved the considerations of the and related to scalar and mass interactions. Moreover, we have found closeness in the introduced approximation scheme for a range of 0.5 to 1.0 fm. In this way, minimal coupling might also yield analytical energy spectra. Within the 2D spatial regime, we have also found that the energy levels of relativistic spin-0 particles increase with increasing interaction energy (i.e., the quantum well width decreases for given values). Additionally, energy levels increase with larger values of the uniform magnetic field. The charge distribution is also valid for the central interaction-confinement space.

A novel analytical unified energy flow calculation method for integrated energy systems based on holomorphic embedding

The multiple energy flow (MEF) calculation plays a key role in the operational analysis of the integrated energy system (IES). This paper proposes a novel analytical unified approach based on the fast and flexible holomorphic embedding (FFHE) method for solving the MEF problem. In the proposed approach, the power flow model of heating and natural gas networks in matrix form is established first. On this basis, the power flow equations of electrical, heating, and natural gas networks are holomorphically embedded in FFHE form, and the recursive equations of each network are determined according to the methodology of the holomorphic embedding (HE) method. By performing the modifications concerning coupling equipment, the recursive relationships of subnetworks are modified and integrated, thereby a unified HE recursive solution form is obtained to solve the energy flow of all networks uniformly. In addition, the Newton–Raphson (NR) method is used to assist in selecting the initial guess for better performance of the proposed approach. Simulation results of the test case verify the accuracy of the proposed FFHE models. Moreover, several case studies are implemented in the testing IES to demonstrate the superiority of the proposed approach in convergence and computational efficiency.

Efficient analytical gradients of property-based diabatic states: Geometry optimizations for localized holes.

We present efficient analytical gradients of property-based diabatic states and couplings using a Lagrangian formalism. Unlike previous formulations, the method achieves a computational scaling that is independent of the number of adiabatic states used to construct the diabats. The approach is generalizable to other property-based diabatization schemes and electronic structure methods as long as analytical energy gradients are available and integral derivatives with the property operator can be formed. We also introduce a scheme to phase and reorder diabats to ensure their continuity between molecular configurations. We demonstrate this for the specific case of Boys diabatic states obtained from state-averaged complete active space self-consistent field electronic structure calculations with GPU acceleration in the TeraChem package. The method is used to test the Condon approximation for the hole transfer in an explicitly solvated model DNA oligomer.

Analytical energy levels of the Schrödinger equation for the improved generalized Pöschl–Teller oscillator with magnetic vector potential coupling

Analytical energy levels of the Schrödinger equation for the improved generalized Pöschl–Teller oscillator with magnetic vector potential coupling

Numerical solution of the one dimensional Schrödinger equation using a basis set of scaled and shifted sinc functions on a finite interval

In this contribution we define a basis set consisting of shifted and scaled sinc functions on the interval [xminx,xmax]. We use this set to numerically solve the Schrödinger equation by using the variational method for the harmonic oscillator and the Morse potential. Good agreement with and rapid convergence to the analytic energy values and wave function is shown.

ANALYSIS OF APPROACHES TO DETERMINING THE QUANTITY OF THERMAL ENERGY FOR THE NEEDS OF HOT WATER SUPPLY IN THE ENERGY CERTIFICATION OF BUILDINGS

In Ukraine, at the legislative level, as part of the implementation of EU Directives, mandatory energy certification has been introduced for certain types of new and reconstructed buildings. In addition, in order to receive financing from various investment funds and the possibility of participating in state or local thermomodernization programs, it is necessary to perform their energy audit and justify energy-saving measures, assess the energy efficiency class. In Ukraine, there is a complex of regulatory acts, methodical documents, construction norms and standards in the field of energy certification, which is constantly updated. The national methodology for calculating energy efficiency indicators has been passed and the by-laws have changed several times, in particular, in the part of accounting for energy consumption for hot water supply, which in turn affected the energy efficiency class. The article evaluates the influence of different approaches to the calculation and accounting of additional revenues from hot water pipelines on the example of a residential multi-story building in Kyiv. As part of the research, a detailed energy survey was carried out using instrumental and analytical methods, the geometric, thermal and energy characteristics of the building were specified, and a set of measures to increase the level of energy efficiency was proposed. As part of the research, a detailed energy survey was carried out using instrumental and analytical methods, a calculation model was formed and a series of calculations was performed. The impact on the specific energy demand, total energy consumption and energy efficiency class of the existing building of changes in the regulatory framework, the features of taking into account utilized heat losses, the number of consumers is shown.

Fractional analysis of radiative blood transport through a porous channel containing multishaped cobalt nanoparticles: An application to hemodynamics

AbstractIn this work, impacts of dispersing nonspherical shaped cobalt nanoparticles in the blood are analyzed for magnetohydrodynamic radiative transport of blood inside a vertical porous channel. An Oldroyd‐B model is used to feature flow characteristics of blood along with Fourier's principle of heat transmission for the mathematical modeling of the problem. A fractional system is constructed by employing the idea of the Caputo–Fabrizio derivative on subsequent differential equations. The Laplace transform method is adopted to solve the fractional flow and energy equations subject to generalized boundary conditions, which involve time‐dependent functions and , respectively. Instead of promoting the analytic velocity and energy expressions, Zakian's numerical algorithm is operated to achieve the reverse transformation purpose of Laplace domain functions. To certify the obtained solutions, two additional numerical algorithms named Stehfest's algorithm and Durbin's algorithm are inculcated in this study, and comparative illustrations are drawn. For the extensive investigation of shear stress and heat transfer phenomenon, numerical simulations for the coefficient of skin friction and Nusselt number are performed, and outcomes are communicated through various tables. The impacts of shape‐dependent viscosity and other significant parameters on flow patterns are investigated through graphs for multiple motion types of the left channel wall. Meanwhile, the thermal performance of nanofluid is examined for platelet, brick, cylinder, and blade shape nanoparticles, along with other thermal parameters. In addition, some recently reported results and flow profiles for Maxwell, second‐grade, and viscous fluids are deduced graphically as special cases of the current study.

Analytical Solutions of the Molecular Kratzer-Feus potential by means of the Nikiforov-Uvarov Method

The analytical methods for solving Schrödinger equation are essential and effective tools with which we can investigate the spectroscopic properties, the electronic structure, and the energetic properties of the diatomic molecules (DMs). Accordingly, in this work, we used the Nikiforov-Uvarov (NU) method to solve the three-dimensional nonrelativistic Schrödinger equation with the molecular Kratzer-Feus (KF) potential and obtain the exact analytical bound state energy eigenvalues as well as their corresponding normalized eigenfunctions. The effective KF diatomic molecular potential well is investigated and represented graphically for several well-known DMs. The bound state energy levels are tabulated numerically for arbitrary values of the vibrational and rotational quantum numbers. The results obtained in this work are found to be in excellent agreement with the already-existing results in the literature.