Energy Equilibrium Research Articles

A Comprehensive Pilot Study to Elucidate the Distinct Gut Microbial Composition and Its Functional Significance in Cardio-Metabolic Disease.

Cardio-metabolic disease is a significant global health challenge with increasing prevalence. Recent research underscores the disruption of gut microbial balance as a key factor in disease susceptibility. We aimed to characterize the gut microbiota composition and function in cardio-metabolic disease and healthy controls. For this purpose, we collected stool samples of 18 subjects (12 diseased, 6 healthy) and we performed metagenomics analysis and functional prediction using QIIME2 and PICRUSt. Furthermore, we carried out assessments of microbe-gene interactions, gene ontology, and microbe-disease associations. Our findings revealed distinct microbial patterns in the diseased group, particularly evident in lower taxonomic levels with significant variations in 14 microbial features. The diseased cohort exhibited an enrichment of Lachnospiraceae family, correlating with obesity, insulin resistance, and metabolic disturbances. Conversely, reduced levels of Clostridium, Gemmiger, and Ruminococcus genera indicated a potential inflammatory state, linked to compromised butyrate production and gut permeability. Functional analyses highlighted dysregulated pathways in amino acid metabolism and energy equilibrium, with perturbations correlating with elevated branch-chain amino acid levels-a known contributor to insulin resistance and type 2 diabetes. These findings were consistent across biomarker assessments, microbe-gene associations, and gene ontology analyses, emphasizing the intricate interplay between gut microbial dysbiosis and cardio-metabolic disease progression. In conclusion, our study unveils significant shifts in gut microbial composition and function in cardio-metabolic disease, emphasizing the broader implications of microbial dysregulation. Addressing gut microbial balance emerges as a crucial therapeutic target in managing cardio-metabolic disease burden.

An improved modulation technique suitable for a three level flying capacitor multilevel inverter

This research paper introduces an innovative modulation technique for controlling a 3-level flying capacitor multilevel inverter (FCMLI), aiming to streamline the modulation process in contrast to conventional methods. The proposed simplified modulation technique paves the way for more straightforward and efficient control of multilevel inverters, enabling their widespread adoption and integration into modern power electronic systems. Through the amalgamation of sinusoidal pulse width modulation (SPWM) with a high-frequency square wave pulse, this controlling technique attains energy equilibrium across the coupling capacitor. The modulation scheme incorporates a simplified switching pattern and a decreased count of voltage references, thereby simplifying the control algorithm.

Coexistence of Nonequilibrium Density and Equilibrium Energy Distribution of Quasiparticles in a Superconducting Qubit

Coexistence of Nonequilibrium Density and Equilibrium Energy Distribution of Quasiparticles in a Superconducting Qubit

Quantum states and static field ionization of a cylindrical confined hydrogen atom: A diffusion Monte Carlo study

AbstractIn this article, the diffusion Monte Carlo (DMC) method is applied to the study of the quantum states of a hydrogen atom confined into a cylindrical potential well. We present an independent reproduction of previous studies based on different methods, in particular the energy eigenvalues for ground and selected excited states and the polarizability of the ground state, both for finite and infinite cylinders. The static field ionization of ground and excited states of the confined atom is discussed, including the determination of the potential energy surface and equilibrium position of the proton. This study provides a further demonstration of the versatility of the DMC method for this and analogous problems.

Computer Simulation of Three-Phase Equilibria for Some Water/n-Alkane Binary Systems.

In this work, the vapor-liquid-liquid equilibrium (VLLE) of the water/n-pentane, water/n-hexane, water/n-octane, and water/n-decane binary systems is calculated by computer simulation using the NVT-Gibbs ensemble (in the version of three simulation boxes) combined with the configurational bias Monte Carlo method. The combination of both methods, the molecular potential models used, and the simulation details allowed us to calculate the triphasic equilibrium properties of the systems studied: the densities of the three phases in equilibrium, their compositions, and potential energies. In previous works, these simulations were not carried out at a temperature range nor water/n-alkanes systems simulated in this work, probably because they are highly nonideal systems; so, to the best of our knowledge, this is the first time that this phenomenon is studied in detail. The results from VLLE simulations of the water/n-pentane system for temperatures from 343.2 to 435 K, the water/n-hexane system for temperatures from 373.11 to 473.15 K, the water/n-octane system for temperatures from 310.9 to 500 K, and for the water/n-decane system for temperatures from 374.15 to 525 K are reported here. The temperature range was selected in concordance with the experimental data available for an adequate study of the VLLE simulation results. The subcritical densities (vapor and liquid rich in n-alkane phases) at various temperatures fit well with the scaling law and the law of rectilinear diameters, allowing the estimation of upper critical end point temperature and density of the VLLE. The simulation results show a good prediction with experimental data reports in the literature.

Energy partitioning among compressional and shear waves in three-dimensional attenuating elastic media.

In strongly scattering elastic media without attenuation and dispersion, the wavefield is dominated by shear waves, and in three dimensions, the ratio of the S to P energy is given by ES/EP=2(vP/vS)3. This study investigates how this ratio is influenced by attenuation. Both the case of the ringdown mode, where the energy evolves from initial values, and the case of energy equilibrium, where the attenuation is balanced by energy injection sources, are treated. It is shown that in ringdown mode, the energy ratio ES/EP satisfies a Ricatti equation in time: hence, the energy ratio is not an exponential function of time. It is also shown that the long-time energy ratio differs from the value in non-attenuating media when the attenuation coefficients for P and S waves are different. In the case of energy equilibrium, the energy ratio only is equal to the value in non-attenuating media when (1) the time scale of P- and S-wave equilibration is much smaller than the attenuation time or (2) the energy injection rate for each wave type is balanced by the dissipation for that wave type. The latter situation happens when the wavefield is excited by thermal fluctuations in thermal equilibrium.

Rational screening of ionic liquids as phase transfer catalysts for aromatic O- and S-glycosidations examplified by acetobromo-alpha-D-galactose with phenolic compound

The heterogeneous liquid–liquid O-glycosidation is a crucial step in pharmaceutical synthesis. Herein, a theoretical methodology based on COSMO-RS, quantum chemical calculations combined with Transformer-CNN model was used to screen ionic liquids (ILs) as phase transfer catalysts (PTCs) to intensify O-glycosidation between 4-nitrophenol and 2,3,4,6-tetra-O-acetyl-α-D-galactopyranosyl bromide. The anions of ILs were screened by the evaluation of ILs hydrophilicity via infinite dilution selectivity of ILs and the molecular descriptor HB_acc3 of the anion using COSMO-RS, a predictive model for thermodynamic properties. Additionally, the binding energy between the phenoxide anion and IL cation was used to assess reaction extent in the aqueous phase through quantum chemical calculation. The cations of ILs were evaluated by the infinite dilution selectivity of the combination between phenoxide anion and IL cations, and physical properties including viscosity and melting point were also predicted using an advanced Transformer-CNN model. The screened IL 1-octyl-3-methylimidazolium acetate and 1-hexyl-3-methylimidazolium acetate were demonstrated its superior catalytic activity for the aromatic O-glycosidation of not only 4-nitrophenol, but also various phenols and thiophenols. Moreover, the presence of PTCs enhances the likelihood of the reactant migrating into another phase. This behavior is validated by COSMO-RS calculated liquid–liquid equilibrium (LLE) and interaction energy analysis. The method provides great potential for screening and designing ILs as phase transfer catalysts for heterogeneous liquid–liquid reactions.

Predictive thermodynamic model for solvent extraction of Iron(III) by tri-n-butyl phosphate (TBP) from chloride media

Hydrometallurgical processes are crucial to reducing the environmental impact of metal recovery, yet dealing with iron impurities is a major challenge. This paper presents a semi-empirical predictive thermodynamic model for iron removal from chloride media by solvent extraction with tri-n-butyl phosphate (TBP). This model is built upon the OLI mixed-solvent electrolyte framework (OLI-MSE). It goes beyond traditional thermodynamic models by incorporating the non-ideality of both the aqueous and organic phases in a single, chemistry-based thermodynamic model. On top of the OLI-MSE framework lies the chemical model that depicts the extraction of Fe(III) by forming an ion pair between the FeCl4– anion and protonated TBP (TBPH+) in the organic phase. The iron(III)-containing ion pair in the organic phase is further stabilized by interactions with neutral TBP molecules. Developing the model required modeling the Fe(III) – chloride chemistry in the aqueous phase, optimizing the HCl extraction model, and fitting the parameters between FeCl4–, TBPH+, and TBP to experimental solvent extraction data. The resulting thermodynamic model can predict the solvent extraction of iron(III) from complex feed solutions by TBP in aliphatic diluents at all concentrations up to undiluted TBP. It can be used to calculate the equilibrium energies and composition, and the species present at equilibrium.

A Review on Harnessing Renewable Energy Synergies for Achieving Urban Net-Zero Energy Buildings: Technologies, Performance Evaluation, Policies, Challenges, and Future Direction

As urbanization continues to accelerate globally, energy demand in cities is reaching unprecedented levels, contributing to greenhouse gas emissions. In response, the concept of net-zero energy building (NZEB) is becoming a sustainable solution for urban energy needs. NZEB aims to achieve a net-zero energy footprint by balancing the energy it consumes with the energy it produces, primarily from renewable energy (RE) sources. This comprehensive literature review-based study explores the role of RE synergies in the context of urban NZEBs, including discussions on definition and development of NZEBs, RE-synergies for achieving NZEBs, sustainable trends and clusters of NZEBs, climate change impacts on NZEBs, their performance evaluation, policy and regulatory frameworks, and challenges and possible solutions related to NZEBs. It has been identified that while customizing NZEB definitions to align with regional energy supply and demand is important, the same is highly dependent on building architectural and micro-climate features. The assessment of climate change effects and NZEB practices should involve evaluating building energy equilibrium, occupant comfort, and interactions with the energy grid. There are still some technical, policy, and socio-economic challenges that need more attention to provide comprehensive solutions for further enhancing the sustainable development/performance of NZEBs and achieving their goal.

A novel time-dependent analytical model for optimizing efficiency and valve timing in Ericsson engines

In this work, a novel analytical time-sensitive model for Ericsson engines was developed taking into account the heat transfer phenomena between the working gas and the cylinder walls in the compressor and the expander. For the calculation of the mass flow entering/exiting each cylinder, another dedicated flow model was developed to account for the pressure drop at the valves. From the energy equilibrium taking into consideration the time-dependent thermal response of the cylinder walls and the enthalpy entering/exiting each cylinder through the valves, an analytical solution of the working gas pressure and temperature can be obtained for every time step and consequently, the thermal efficiency of the engine can be calculated. A case study was performed where the thermal efficiency of an Ericsson engine was calculated for different rotational speeds and heat exchanger gas temperatures. It was observed that with higher temperatures thermal efficiency maintained a more stable behaviour with a weak dependence on rotational speed. The thermal efficiency of the engine in the performed case studies was found in the range of 10% to 14%. The valve timing of the Ericsson engine was optimized in order to achieve the highest thermal efficiency possible. The thermal efficiency of the engine could be increased up to 26% as a percentage after a thorough optimization of the valve timing. Finally, backflow phenomena accounting for thermal efficiency drop were studied. The developed model can also be applied to other types of external combustion engines such as Stirling engines.

A DFT calculation of electronic structures, magnetic, and thermoelectric properties of the new equiatomic quaternary Heusler alloy RuTiCrSi

AbstractThe stabilities, mechanical, electronic, and magnetic properties of the new equiatomic quaternary Heusler alloy (EQHA) RuTiCrSi were investigated using the Kohn‐Sham DFT (KS‐DFT) calculations within the generalized gradient approach (GGA), the modified version of the exchange potential introduced by Becke and Johnson in addition to the GGA (mBJ‐GGA), and Heyd‐Scuseria‐Ernzerhof (HSE06) hybrid functional. The ground‐state equilibrium energy reveals that the ferromagnetic with type 2 structure is the more stable. The RuTiCrSi is energetically, mechanically, and dynamically stable. The calculated self‐consistent total magnetic moment is 2 μB and agrees well with the Slater‐Pauling rule of . The electronic structure results from mBJ‐GGA and HSE06 functionals show a half‐metallic behavior. A high Curie temperature is obtained using the mean‐field approximation. The thermoelectric response was calculated using the semi‐classical Boltzmann transport equation under constant relaxation time. The maximum value of Seebeck coefficient is observed at the ambient temperature of . It was also observed that the power factor increases significantly as temperature rises. Therefore, the new EQHA RuTiCrSi seems to be a potential candidate for spintronic thermoelectric applications.

Multi-objective configuration and evaluation of dynamic virtual inertia from DFIG based wind farm for frequency regulation

Modern power systems are gradually evolving into low-inertia systems due to the integration of high penetration of renewable energy and power electronic equipment. For the natural inertia on the rotor, doubly-fed induction generator (DFIG) based wind farms are expected to provide inertia support for systems. The paper proposed an analytical model of DFIG with df/dt inertia control for studying frequency dynamics, and investigates the optimal design of virtual inertia from wind farms, as well as its equivalent inertia contribution to system. The inertia response differences between DFIG and synchronous generator (SG) are discussed and analyzed for the first time, and then to accurately describe the frequency response with low cost, an analytical model of DFIG with inertia control is developed considering wind turbine aerodynamic characteristics. The explicit expression of virtual inertia provided by DFIG is derived according to the kinetic energy equilibrium, and the key factors that dominate the magnitude of virtual inertia are illustrated. Based on the system frequency response model including wind farms, taking the system frequency nadir (SFN) and the time of reaching nadir (ToN) as targets, a multi-objective optimal configuration model of virtual inertia is constructed and solved through MOPSO. The time domain simulations of a generic two machine four bus system and modified IEEE 9-bus test system are both performed in MATLAB/Simulink, the accuracy and efficiency of our proposed DFIG model on system frequency dynamics research are demonstrated, the pareto frontiers of virtual inertia configuration under different working conditions are optimized and analyzed as well as the impacts of different parameters on inertia evaluation.

Molecular Dynamics simulations and discrete perturbation theory for systems interacting via the parabolic-well pair potential

In this work, we performed Molecular Dynamics (MD) simulations to investigate the thermodynamic properties, including vapor pressures, critical points, pressure, excess energy, and vapor-liquid equilibrium, for a continuous version of the parabolic-well (PW) pair potential within the attractive range of 1.5 ≤λ≤3.0. In addition to conducting extensive MD simulations, we have developed an analytical equation of state for the Helmholtz free energy of particles interacting via the PW pair potential. This development was accomplished within the framework of discrete perturbation theory, involving discrete steps to accurately represent the general shape of the PW potential. Remarkably, our theoretical approach based on discrete perturbation theory demonstrates excellent agreement with MD simulations across a wide range of densities, temperatures, and pressures for the PW pair potential. Our findings demonstrate that PW fluids, characterized by long-range attractive interactions, deviate from the principle of corresponding states. However, for short-range attractive interactions, the fluids moderately follow the Ising universality class. Finally, the integration of discrete perturbation theory with MD simulations proves to be an efficient method for exploring the behavior of molecular fluids and colloidal systems.

ბუნებრივი რესურსის ბაზაზე მიღებული სორბენტებით CO2-ის ადსორბციისას შესაძლო პროცესთა თერმოდინამიკური ანალიზი

This research paper examines the potential mechanisms involved in the adsorption of carbon dioxide using sorbents derived from the natural resources found in Georgia (with a primary focus on zeolite-based materials). A succinct characterization of zeolites obtained from the Dzegvi deposit is provided, along with the presentation of the average chemical composition of the collected samples. The study identifies three distinct series of reactions for in-depth investigation. According to the referenced sources, the standard molar values of the thermodynamic properties of the substances involved in the reaction are sought. The Gibbs free energy minimization method is employed to ascertain both the magnitudes and directions of the free energy changes and equilibrium constants for the proposed reactions within the temperature range spanning 400 to 1200 Kelvin. Their temperature dependence is expressed graphically. Reactions are evaluated based on thermodynamic point of view.

Relay node selection scheme and deep sleep period for power management in energy‐harvesting wireless sensor networks

SummaryThis paper presents Relay node selection scheme and Deep sleep period for power management in Energy Harvesting Wireless Sensor Networks (RD‐EHWSN), a new energy‐saving scheme founded on asynchronous duty cycling. RD‐EHWSN reduces sensor node energy consumption and guarantees equilibrium energy use between sensor nodes in WSN with the energy harvesting capacity by adjusting these sensor nodes duty cycles more drastically and deeply by according to the estimated value of its residual energy on the basis of future‐presented harvested energy, and this is done through the use of a new proposed energy threshold policy. RD‐EHWSN also grips the benefit of transmitter initiated using the low power listening (LPL) technique with short preamble messages and uses a new relay node selection procedure to achieve the load balancing in WSN. We implemented RD‐EHWSN by using OMNeT++/MiXiM. For evaluation, we compared it with PS‐EHWSN, under multiple concurrent multihop traffic flows scenarios and scenarios in which nodes can harvest different energy harvesting rate. In all experiments, RD‐EHWSN significantly outperformed the PS‐EHWSN scheme; the results of simulation demonstrate that our scheme enhances the general yielding of WSN thru lessening the energy consumption and the mean latency, as well as raising the packet delivery ratio and the throughput. Moreover, RD‐EHWSN improves the WSN lifetime and ensures it operates in good condition in the case where the energy harvesting rate is lower by comparing it with the PS‐EHWSN scheme.

Improved SST turbulence model for supersonic flows with APG/separation

A goal in modeling the turbulent flows in computational fluid dynamics is to find an empirical yet universal model to address the complex scenarios. Menter's Shear Stress Transfer (SST) [1] is a Reynolds-Averaged Navier-Stokes (RANS) based two-equation turbulence model and has been one of the most widely used turbulence models for numerical simulation of viscous flows. However, in some practical cases on supersonic, the standard SST model shows unsatisfactory prediction of flow separation and the often underestimation of Reynolds stress. The error mainly comes from the inappropriate use of Bradshaw's assumption which is proposed under turbulent kinetic energy (TKE) equilibrium flow conditions. This paper proposes an improved SST turbulence model which combines the structural parameter with the ratio of the turbulence generation term to the dissipation term and imposes a mixing function to correct the logarithmic and wake parts of the region. Several supersonic test cases are carried out to verify the new model. The calculation results show that the new model exhibits better performance in capturing the separation zones than the baseline model (BSL) and the standard SST model.

Probing the structural and electronic properties of MAX phases and their corresponding MXenes using first-principles calculations

Abstract This study delves into the theoretical exploration of the structural and electronic characteristics of 2D monolayer MXenes (M n + 1X n ) by the elimination of Al layers from their corresponding MAX-phases, M n + 1AX n (n = 1–3), through meticulous first-principles calculations. The study encompasses structural optimization and the determination of key ground state properties, including equilibrium lattice constants, energy (E 0), and volume (V 0) of both MXenes and their corresponding MAX phases. Consequently, we investigated the comparative study of the electronic properties of M n + 1AlC n (M = Ti, V, or Cr) (n = 1–3) and their MXenes for the first time by calculating the Bader charge analysis (MAX phase only) and the density of states (DOS). The analysis extends to the density of states and Bader charge assessments, facilitating a comprehensive comparison. Remarkably, the MXene monolayer showcases an elevated density of states at the Fermi level compared to its MAX phase counterpart. This disparity stems from the redistribution of 3d electrons near the Fermi level following the removal of Al layers, consequently enhancing electronic conductivity. Cohesive energy and formation energy calculations affirm the structural stability of these compounds. Furthermore, our computed values are meticulously cross-referenced with existing experimental and theoretical data, stimulating the reliability and significance of our findings.

Effect of swap and antisite disorder on electronic, mechanical and thermodynamic properties of equiatomic all-d-metal Heusler alloy NiVTiZn

The influence of atomic disorder on electronic, mechanical and thermodynamic properties of equiatomic quaternary all-d metal Heusler alloy NiVTiZn is studied by employing the first-principles calculations. The ground state of NiVTiZn is confirmed to be α-type structure with ferromagnetic nature, the calculated spin down energy gap and equilibrium lattice constant is ∼0.7 eV and 6.048 Å, respectively. The half metallicity could be maintained when uniaxial strain ratio increases from −7.28 % to 9.59 % and when c/a ratio ranges from 0.92 to 1.06, showing a robust half metallicity against the strain effect and tetragonal distortion. Six types of atomic swap disorder and twelve types of atomic antisite disorder are proposed. The V(Ni) and V(Zn) antisite disorders as well as V-Ni and V-Zn swap disorders are the most favorable owing to their negative formation energies. The 100 % spin polarization is preserved in V(Ti), Ni-Zn and V-Ti disordered structures although the width of band gap suffers contraction. The spin polarization of Ni(V), Ni(Zn), V(Zn) and Zn(Ni) disordered structures is also larger than 80 %. In addition, the effect of various disorder on mechanical and thermodynamic properties is also studied in detail.

Hypothalamic AMP-Activated Protein Kinase as a Whole-Body Energy Sensor and Regulator.

5´-Adenosine monophosphate (AMP)-activated protein kinase (AMPK), a cellular energy sensor, is an essential enzyme that helps cells maintain stable energy levels during metabolic stress. The hypothalamus is pivotal in regulating energy balance within the body. Certain neurons in the hypothalamus are sensitive to fluctuations in food availability and energy stores, triggering adaptive responses to preserve systemic energy equilibrium. AMPK, expressed in these hypothalamic neurons, is instrumental in these regulatory processes. Hypothalamic AMPK activity is modulated by key metabolic hormones. Anorexigenic hormones, including leptin, insulin, and glucagon-like peptide 1, suppress hypothalamic AMPK activity, whereas the hunger hormone ghrelin activates it. These hormonal influences on hypothalamic AMPK activity are central to their roles in controlling food consumption and energy expenditure. Additionally, hypothalamic AMPK activity responds to variations in glucose concentrations. It becomes active during hypoglycemia but is deactivated when glucose is introduced directly into the hypothalamus. These shifts in AMPK activity within hypothalamic neurons are critical for maintaining glucose balance. Considering the vital function of hypothalamic AMPK in the regulation of overall energy and glucose balance, developing chemical agents that target the hypothalamus to modulate AMPK activity presents a promising therapeutic approach for metabolic conditions such as obesity and type 2 diabetes mellitus.

Performance Investigation of Asphaltene Adsorption at a Carbonate Rock Surface: Spectroscopy Experiment and Molecular Simulation.

Investigation of asphaltene adsorption at rock surfaces plays an important role in enhanced oil recovery (EOR) for the petroleum industry. In this work, the interaction performances of asphaltene adsorption at carbonate dolomite and calcite surfaces are investigated based on experimental and simulation insights. On the one hand, macroscopic interaction performances were investigated by spectroscopy experiments to obtain the Langmuir thermodynamic model and pseudo-second-order (PSO) kinetic model. The results indicated monolayer molecular asphaltene adsorption for both dolomite and calcite, while they showed 'slow adsorption-slow desorption' for dolomite but 'fast adsorption-fast desorption' for calcite. Meanwhile, dolomite showed a higher adsorption capacity with qm(dol1) = 5.35 mg/g > qm(cal1) = 1.28 mg/g and a stronger adsorption spontaneity with ΔGm(dol1)θ = -7.76 kJ/mol < ΔGm(cal1)θ = -4.76 kJ/mol. On the other hand, microscopic interaction performances were investigated for three asphaltene molecules by molecular dynamics simulation (MDS) with ∼8 Å distance-placing and 500 ps time-running. According to the results, dolomite showed higher system stability than calcite with a lower final energy of ΔEdol-cal = -58 kJ/mol, and archipelago asphaltene showed higher adsorption stability with the smallest equilibrium energy of Earch(dol) = -147 kJ/mol for albite and Earch(cal) = -89 kJ/mol for calcite. The model of molecular orientation and force dominance was proposed as the interaction mechanism for asphaltene adsorption, which "lie sideways" at low concentrations but "stands upright" at high concentrations. This work allows the performance investigation and mechanism illustration of asphaltene adsorption at rock surfaces, which can help gain a fundamental understanding of the EOR during reservoir exploitation.