Energy Components Research Articles

Planetesimal gravitational collapse in a gaseous environment: Thermal and dynamic evolution

Planetesimal formation models often invoke the gravitational collapse of pebble clouds to overcome various barriers to grain growth and propose processes to concentrate particles sufficiently to trigger this collapse. On the other hand, the geochemical approach for planet formation constrains the conditions for planetesimal formation and evolution by providing temperatures that should be reached to explain the final composition of planetesimals, the building blocks of planets. To elucidate the thermal evolution during gravitational collapse, we used numerical simulations of a self-gravitating cloud of particles and gas coupled with gas drag. Our goal is to determine how the gravitational energy relaxed during the contraction is distributed among the different energy components of the system, and how this constrains a thermal and dynamical planetesimal's history. We identify the conditions necessary to achieve a temperature increase of several hundred kelvins, and as much as 1600 K. Our results emphasise the key role of the gas during the collapse.

Weather-aware energy management for unmannedaerial vehicles: a machine learning application with global data integration

This study introduces a machine learning (ML) framework to predict unmanned aerial vehicle (UAV) energy requirements under diverse environmental conditions. The framework correlates UAV flight patterns with publicly accessible weather data, to yield an energy management tool applicable to a wide range of UAV configurations. The model employs the Cross-industry standard process for data mining and advanced feature engineering, offering an in-depth analysis of meteorological factors and UAV energy demands. The study assesses several multi-regression linear and ML models, whereby ensemble models gradient boosting (GB) and eXtreme gradient boosting demonstrate superior performance and accuracy. Specifically, the GB model achieved a test mean absolute error (MAE) of 0.0395 V (V) for voltage, 0.808 A (A) for current, and 9.758 mA-hours (mAh) for discharge, with prediction accuracy of over 99.9% for voltage and discharge, and 97% for current, derived from the coefficient of determination (R2). A novel integration of real-world UAV logs and weather data underpins the development of a weather-aware ML prediction model for UAV energy consumption. Our framework is capable of concurrently predicting three components of energy and power with almost uniform accuracy, a feature not found in contemporary models. Empirical test flights show a discrepancy of only 0.005 W-hour (Wh) between total predicted and actual energy consumption. This work enhances both efficiency and safety in UAV operations. The resulting energy-predictive flight planning tool sets a new benchmark for artificial intelligence (AI) applications in intelligent automation for UAVs.

Simple model for the fracture of a polymer chain: Single-bond potential of mean force and tension-based rate constants for chain rupture

A linear chain of N particles connected by Morse bonds with periodic boundaries in a Brownian bath is considered as a model for polymer fracture. The potential of mean force (pomf) with respect to the length of a bond and its energy and entropic components are computed via Langevin Dynamics simulations at various chain elongations λ > 1. A narrow range of λ values is identified over which equilibrium is established between an intact (i) and a fractured (f) state over a pomf barrier. While the barrier and (f) regions of the pomf are well described by a well-known (N − 1)-bond adiabatic approximation, the shape of the (i) region departs from it, exhibiting a bimodal character. A new, 1-bond adiabatic approximation is proposed to explain this. The lower envelope of the two adiabatic approximations provides an excellent description of the pomf. The relationship between (f) states for individual bonds and for the entire chain is elucidated. A new approach, based on analysis of equilibrium tension autocorrelation functions, is developed to extract rate constants for the fracture and reformation of the chain in dependence of λ. Results from it agree with tension relaxation during nonequilibrium simulations initiated at equispaced configurations of the particles. Rate constants for chain fracture conform to a Boltzmann–Arrhenius–Zhurkov dependence on the tension averaged over the intact state of the chain, the activation length being higher than estimated from pomf extrema. These findings constitute a step toward a predictive multiscale simulation scheme for fracture in polymeric materials.

Early dark energy during big bang nucleosynthesis

We study the impact of an early dark energy component (EDE) present during big bang nucleosynthesis (BBN) on the elemental abundances of deuterium D/H, and helium Yp, as well as the effective relativistic degrees of freedom Neff. We consider a simple model of EDE that is constant up to a critical time. After this critical time, the EDE transitions into either a radiation component that interacts with the electromagnetic plasma, a dark radiation component that is uncoupled from the plasma, or kination that is also uncoupled. We use measured values of the abundances and Neff as determined by cosmic microwave background observations to establish limits on the input parameters of this EDE model. In addition, we explore how those parameters are correlated with BBN inputs; the baryon to photon ratio ηb, neutron lifetime τn, and number of neutrinos Nν. Finally, we study whether this setup can alleviate the tension introduced by recent measurements of the primordial helium abundance. Published by the American Physical Society 2024

Perturbational Analysis of Magnetic Force Theorem for Magnetic Exchange Interactions in Molecules and Solids

There have been increasing efforts to compute magnetic exchange coupling constants for transition metal complexes and magnetic insulators using the magnetic force theorem and Green’s function-based linear response methods. These were originally conceived for magnetic metals, yet it has not been clear how these methods fare conceptually with the conventional models based on electron-correlation interactions among so-called magnetic orbitals. We present a spinor-based theoretical analysis pertinent to the magnetic force theorem and linear response theory using Brillouin–Wigner perturbation method and Green’s function perturbation method, and we shed light on the conceptual nature of the Lichtenstein formula in its applications for calculations of the total energy and magnetic exchange coupling constants for both molecules and solids. Derivation of the magnetic force theorem in this perturbational analysis identifies the first-order energy correction terms, which are considered as the ferromagnetic component for the magnetic exchange interactions of transition metal compounds but are not included in the Lichtenstein formula. Detailed perturbational analysis of the energy components involved in the magnetic force theorem identifies the energy components that are missing in the Lichtenstein formula but are critical in the Anderson’s model for transition metal complexes and magnetic insulators where magnetic orbitals can overlap.

Energy balance during Bragg wave resonance by submerged porous breakwaters through a mixture theory-based δ-LES-SPH model

This paper presents a numerical analysis of the time behaviors of mechanical and internal fluid energies during the Bragg wave resonance induced by two-arrayed trapezoidal submerged porous breakwaters based on a reformatted δ-LES-SPH model (Di Mascio et al., 2017). In the present work, a mixture theory is introduced into the δ-LES-SPH model by reformulating the governing equations with the incorporation of a volume fraction. In this approach, the viscous and diffusive terms are also modified by the volume fraction. The energy equation is then written for the presented model highlighting the presence of two additional components compared with the classical δ-LES-SPH formulation: one coming from the fluid compression and another one due to the dissipation both induced by the interaction of the porous structure with the fluid phase. The numerical results are validated by available experimental data for a gravity-driven mass flow passing through a porous dam case and two Bragg wave resonance by two-arrayed submerged trapezoidal porous breakwaters cases. A numerical analysis is then conducted on Bragg wave resonance by two-arrayed trapezoidal porous breakwaters, by investigating the effects of the distance between the two breakwaters and their porosity. Interesting insights about the type and magnitude of dissipation occurring during the wave-structure interaction are captured by analyzing the time evolutions of each energy component.

Cascading Dark Energy

The standard cosmological model is in the midst of a stress test, thanks to the tension between supernova-based measurements of the Hubble constant H 0 and inferences of its values from cosmic microwave background (CMB) anisotropies. Numerous explanations for the present-day cosmic acceleration require the presence of a new fundamental scalar field, as do early dark energy solutions to the Hubble tension. This raises the possibility that multiple fields cooperatively contribute to the dark energy component in bursts throughout cosmic time due to distinct initial conditions and couplings. Here, this cascading dark energy scenario is illustrated through a realization that effectively reduces to a two-field model, with two epochs in which dark energy is cosmologically significant. The model is compared to measurements of the CMB and baryon acoustic oscillations, as well as both PANTHEON and SH0ES observations of Type Ia supernovae. Neglecting the linear perturbations, it is found that this scenario ameliorates the Hubble tension, improving over purely late-time models of dark energy and the agreement between the galaxy survey measurements of baryon acoustic oscillations.

Maxwell–Dirac system in cosmology

Within the scope of a Bianchi type-I (BI) cosmological model, we study the interacting system of spinor and electromagnetic fields and its role in the evolution of the Universe. In some earlier studies, it was found that in the case of a pure spinor field, the presence of nontrivial nondiagonal components of energy–momentum tensor (EMT) leads to some severe restrictions both on the space–time geometry and/or spinor field itself, whereas in the case of electromagnetic field with induced nonlinearity, such components impose severe restrictions on metric functions and the components of the vector potential. It is shown that in the case of interacting spinor and electromagnetic fields, the restrictions are not as severe as in the other cases and in this case, a nonlinear and massive spinor field with different components of vector potential can survive in a general Bianchi type-I space–time.

A novel application of inverse gas chromatography for estimating contact angles in porous media

HypothesisSurface wettability is a critical factor in multi-phase flow within porous media, a processes essential in various applications e.g. in the energy sector. Traditional methods for assessing wettability of porous media by contact angle measurements, such as sessile droplet and micro-CT techniques, are limited by interface pinning, sample size or resolution impacting precision and accuracy. We hypothesized that using smaller and unconstrained probes, specifically gas molecules, to retrieve interactions along a representative sample size via inverse gas chromatography (IGC) could provide a more accurate determination of contact angles. MethodWe propose a procedure to relate IGC results with macro-scale wettability descriptions, such as the Young equation. To test the effectiveness of IGC method, glass bead samples with varying wettability, modified through a silanization process, were prepared. Contact angles for a distilled water-air-sample system were measured using the sessile droplet method and micro-CT for comparative analysis. IGC was employed to determine the surface energy components of these samples, which were then used in the extended Young-Dupré equation to calculate the contact angles. FindingsThe contact angle ranges determined by IGC and micro-CT for untreated glass beads, the most hydrophilic samples, showed great alignment. This consistency is attributed to the chemical amorphous nature of the untreated beads reflected in the assumption that dispersive and specific energetic components of surface sites are uncorrelated, on which the proposed analysis is based. For treated samples, where the silanization process creates correlations between surface energetic components, the alignment between IGC and micro-CT results was less precise. This study successfully demonstrated that IGC, a molecular-scale probe-based technique, can effectively determine the contact angle range, a macroscopic property, for amorphous samples. Future work should incorporate correlations between energetic components of surface detected by IGC to extend this method's applicability to a wider material range.

Nanostructures/TiN layer/Al2O3 layer/TiN substrate configuration-based high-performance refractory metasurface solar absorber

Metasurface solar absorber serves as a kind of important component for green energy devices to convert solar electromagnetic waves into thermal energy. In this work, we design a new solar light absorber configuration that incorporates the titanium nitride substrate, aluminum oxide layer, titanium nitride layer, and the topmost refractory nanostructures. The metasurface absorber based on this configuration can achieve an average spectral absorption of over 91% and a total solar radiation absorption of 91.5% at ultra-wide wavelengths of 300–2500 nm. It is discovered that the excellent performance of the proposed metasurface absorber is attributed to the synergistic effects of surface plasmonic effect and Fabry–Pérot (FP) cavity resonance by comprehensive analysis of the simulated field distributions. Furthermore, the effect of geometrical parameter of the proposed configuration on absorber performance is studied, indicating the proposed configuration possesses a large fabrication tolerance. Moreover, the proposed configuration is not sensitive to the polarization direction and the angle of incident light. It is also found that the use of other refractory metal materials and other shapes as the topmost absorbent nanostructures also have good results with this configuration. This work can offer a universal platform for constructing and guiding the design of refractory metasurface solar absorbers.

Study on recrystallization process of nitroguanidine by directly adding cold water to control temperature

Abstract Nitroguanidine (NGu), as a kind of high-energy material, is widely used as explosive propellant and energy component of explosives and smokeless powder. However, NGu crystals prepared by crystallization process are hollow and long needles, and their bulk density and bombing performance are greatly limited due to the high energy density at the tip, large porosity, and poor fluidity. Surprisingly, the particle size and morphology of NGu can effectively be improved by the recrystallization process. In this article, the recrystallization process by directly adding cold water to control temperature is first proposed, aiming to improve the morphological characteristics and reduce the particle size of NGu. Through single factor experimental research, the influences of various operating parameters on the morphology and particle size of NGu during recrystallization process were studied in detail. The results showed that the smallest average particle size of NGu was 19.8 μm when the crude NGu concentration, cold water temperature, volume ratio of boiling to cold water, stirring speed, and polyvinyl alcohol concentration were 5 g/100 mL, 0°C, 1:1, 800 rpm, and 0.35 g/100 mL, respectively. Correspondingly, the morphology of NGu was short rod, which was helpful to improve the bulk density. This novel recrystallization process has great potential to improve the NGu morphological characteristics, providing a new idea for the preparation of military NGu with small particle size and high bulk density.

Establishing fire protection patterns in wood using impregnation compositions from inorganic salts

An issue related to using inorganic salts for fire protection of wood is to ensure their flame-inhibiting ability and compatibility with wood and application technology. That is why the object of research was to establish the effectiveness of inhibitory properties of mixtures of inorganic salts during interaction with the flame and enabling interplay with wood. A synergistic increase in the inhibitory capacity of mixtures of aqueous solutions of salts of diammonium phosphate and ammonium sulfate at a ratio of 2:1, and for a mixture based on orthophosphoric acid, urea, and oxyethylidenediphosphonic acid in the concentration range of 20–25 % by mass, has been proven. During the interaction of the specified mixtures with the wood surface, it was found that after application to the wood surface, the dispersed component of the free energy of the wood surface decreased to zero; instead, the polar component increased 13 times, which indicates a change in the wood surface. During the tests of wood samples on the effect of the burner flame, it was found that the untreated sample ignited on second 53, and the flame spread throughout the sample for 102 s. On the other hand, the samples treated with a mixture of an aqueous solution of phosphate and ammonium sulfate, as well as a mixture of aqueous solutions based on orthophosphoric acid and urea and oxyethylidenediphosphonic acid, did not catch fire, the flame did not spread over the surface, and the flammability index was 0. The practical significance is that the results were taken into account when designing flame retardant compositions for wood. Thus, there are reasons to assert the possibility of targeted regulation of wood protection processes through the use of mixtures of inorganic salts capable of forming a protective layer on the surface of the material that inhibits the burning of wood

Cosmology in modified f (𝒢) gravity: a late-time cosmic phenomena

ABSTRACT In this work, we present a method for numerically solving the Friedmann equations of modified $f(\mathcal {G})$ gravity in the presence of pressureless matter. This method enables us to predict the redshift behaviour of the Hubble expansion rate. To evaluate the credibility of the model, we applied a Bayesian MCMC technique using late-time cosmic observations to impose limitations on the free parameters of the Gauss–Bonnet model. Our results suggest that the $f(\mathcal {G})$ model can reproduce the low-redshift behaviour of the standard Lambda cold dark matter ($\Lambda$CDM) model, but there are significant differences at high redshifts, leading to the absence of a standard matter-dominated epoch. We also examined the profiles of cosmographic parameters using the model parameter values from the standard range to verify the intermediate epochs. Our analysis shows that the highly promising $f(\mathcal {G})$ model is a feasible candidate for explaining the current epochs. We presented a dynamical system analysis framework to examine the stability of the model. Our study identified critical points depicting various phases of the Universe and explained the evolutionary epochs. We demonstrated that the model effectively captures the evolution of energy components over cosmic time, supporting its validity as an alternate explanation for the observed acceleration of the Universe.

Quantum chemical calculation dataset for representative protein folds by the fragment molecular orbital method

The function of a biomacromolecule is not only determined by its three-dimensional structure but also by its electronic state. Quantum chemical calculations are promising non-empirical methods available for determining the electronic state of a given structure. In this study, we used the fragment molecular orbital (FMO) method, which applies to biopolymers such as proteins, to provide physicochemical property values on representative structures in the SCOP2 database of protein families, a subset of the Protein Data Bank. Our dataset was constructed by over 5,000 protein structures, including over 200 million inter-fragment interaction energies (IFIEs) and their energy components obtained by pair interaction energy decomposition analysis (PIEDA) using FMO-MP2/6-31 G*. Moreover, three basis sets, 6-31 G*, 6-31 G**, and cc-pVDZ, were used for the FMO calculations of each structure, making it possible to compare the energies obtained with different basis functions for the same fragment pair. The total data size is approximately 6.7 GB. Our dataset will be useful for functional analyses and machine learning based on the physicochemical property values of proteins.

The Global Atmospheric Energy Cycle in TaiESM1: Present and Future

AbstractThe Lorenz Energy Cycle (LEC) in the Taiwan Earth System Model Version 1 (TaiESM1) historical simulation is calculated and compared with ERA5 to evaluate the model performance from the thermodynamic aspect. The future change of LEC is accessed by comparing the SSP5‐8.5 and historical simulations in TaiESM1. TaiESM1 reasonably simulates the global mean, seasonal cycle, and spatial patterns of the energy reservoirs with larger values in the mean energy components and smaller in the eddy energy components. The energy cycle in TaiESM1 is about 35%–45% stronger than ERA5, except from December to February. The impact of global warming on the LEC is different at the vertical levels. The influence of meridional temperature gradient change is the dominant factor in the intensity of the energy cycle, and the change in static stability only contributes to the lower troposphere. Lifting the tropopause in the tropics increases the meridional temperature gradient and produces more zonal mean potential energy (PM) in the upper troposphere. PM is the primary driver of the LEC and leads to a more active energy cycle in the upper troposphere. As the tropical tropospheric depth increases and the mid‐latitude eddy activities become more active, more (less) energy is stored in the upper (lower) troposphere, and the energy conversion processes tend to become stronger (weaker) in the upper (lower) troposphere.

Investigation of orientation behavior of nematic liquid crystals on UV-irradiated polyimide films

Abstract The orientation mechanism of liquid crystals (LCs) on surfaces remains unclear, despite several methods for controlling pretilt angles. This study investigates the relationship between the surface condition of polyimide films, whose pretilt angles can be controlled by UV dose, and LC orientation behavior. Absorbance at wavelength of 200 nm and 260 nm significantly decrease, while thickness reduces approximately 4 nm. A rubbing treatment further decreases the thickness by approximately 2 nm. Atomic force microscopy confirmed the change in molecular conformation by UV-irradiation and rubbing treatment. The dispersive and polar components of the surface free energy of UV-irradiated polyimide films are evaluated, it’s found that only the polar component changes with UV dose. Additionally, we confirm that the alignment of LCs transitions from homeotropic to planar with increased UV irradiation, demonstrating that pretilt angle distribution can be spatially controlled. These results contribute to establishing a photoalignment method for pretilt angle control.

Influence of Lactation Stage on Content of Neurotrophic Factors, Leptin, and Insulin in Human Milk.

Human milk comprehensively meets the nutritional needs of a child, providing not only structural and energy components but also various bioactive factors. Among these, neurotrophic factors and hormones involved in metabolic processes deserve special attention. Studies using enzyme-linked immunosorbent assays compared the content of neurotrophic factors-CNTF, NT-3, and NGF-and hormones, leptin and insulin, in two groups of breast milk samples: early lactation (1-3 months) and extended lactation (>6 months, up to 12 months). The results indicated changes in leptin and insulin levels as the lactation period extended. NGF, leptin, and insulin were present in milk samples from both study groups, with leptin and insulin levels being higher in the early lactation group. CNTF and NT-3 were not detected in any of the samples from either study group. The analyses confirmed that human milk from women who breastfeed for extended periods remains a source of biologically active components and macronutrients that support a child's development and health.

Energy Reserve Allocation in the Trade-Off between Migration and Reproduction in Fall Armyworm.

Striking a trade-off between migration and reproduction becomes imperative during long-range migration to ensure proper energy allocation. However, the mechanisms involved in this trade-off remain poorly understood. Here, we used a takeoff assay to distinguish migratory from non-migratory individuals in the fall armyworm, which is a major migratory insect worldwide. Migratory females displayed delayed ovarian development and flew further and faster than non-migratory females during tethered flight. Transcriptome analyses demonstrated an enrichment of fatty acid genes across successive levels of ovarian development and different migratory behaviors. Additionally, genes with roles in phototransduction and carbohydrate digestion along with absorption function were enriched in migratory females. Consistent with this, we identified increased abdominal lipids in migratory females that were mobilized to supply energy to the flight muscles in the thorax. Our study reveals that the fall armyworm faces a trade-off in allocating abdominal triglycerides between migration and reproduction during flight. The findings provide valuable insights for future research on this trade-off and highlight the key energy components involved in this strategic balance.

Assessing the Noncovalent Interaction of Deucravacitinib and Ethanol with Special Reference to an Independent Gradient Model Based on Hirshfeld Partition.

The current study begins by optimizing the deucravacitinib molecule in the gas phase at the ωB97XD/cc-pVDZ level of theory using density functional theory and proceeds to study its intramolecular interactions. Further, a molecule of EtOH was introduced at different locations on the deucravacitinib molecule, and the noncovalent interactions arising from them were also investigated using several computational tools. In this way, eight deucravacitinib-EtOH systems (1-8) were identified and their electronic environment was studied after evaluating their binding energy. Using natural bond orbital analysis, the localization of charges between the donor and acceptor fragments in these interacting systems was examined. The nature of interactions was analyzed using the reduced gradient approach (NCI analysis), and few hydrogen bonding interactions (intermolecular and intramolecular) were found in each system. The strength of these hydrogen bonding interactions was further investigated by using theoretical tools such as atoms in molecules analysis and independent gradient model based on Hirshfeld partition analysis. The binding energy of deucravacitinib with EtOH was decomposed into energy components based on the domain-based local pair natural orbital coupled cluster technique using LED analysis. The results from the hydrogen bonding interaction analysis using different computational tools were found to be consistent with the calculated order of binding energy of systems 1-8 and they also pointed toward the higher stability of system 3.

Investigating the impact of acetylenic linkage in C20 fullerene: Utilization in optoelectronic devices and as anode material

This study delves into the diverse characteristics of C80 fulleryne, derived from the incorporation of acetylenic linkages into each chain of the smallest fullerene, C20. Utilizing advanced theoretical computations, we confirm the stability of C80 fulleryne. Notably, its possession of a finite energy gap (0.743 eV) categorizes it as a semiconductor. Further enlightenment into its structural stability, bonding and reactivity stems from an exploration of different energy components, topological descriptors of electron density and chemical reactivity parameters. C80 fulleryne can act as radical scavenger owing to its higher electron affinity (5.5 eV). Spectral analysis revealed the C80 fulleryne’s absorption within the near-infrared region and its intriguing optical transparency with negligible loss in specific regions of the electromagnetic spectrum. Additionally, our investigation scrutinized the viability of C80 fulleryne as an anode material in Lithium-ion batteries. The presence of low adsorption energy (−1.693 eV) and significant amount of Bader charge transfer (0.917 e) between Li-ion and C atoms of C80 fulleryne confirms that Li-ion gets chemisorbed on the C80 fulleryne. Remarkably, this cage acts as a storehouse to host 12 Li ions, precisely one for each of its constituent pentagons within the C80 fulleryne structure, bearing a theoretical capacitance of 335 mAhg−1.