Energy Fluctuations Research Articles

Universal Energy Fluctuations in Inelastic Scattering Processes

Universal Energy Fluctuations in Inelastic Scattering Processes

Manifestations in nature of self-controlled quasi-stationary nuclear fusion into magnetized low-temperature hydrogen plasma

This paper examines the characteristics of nuclear reactions occurring in low-temperature magnetized deuterium plasma. It is demonstrated that considering the ionization-recombination dynamics of deuterium atoms in this plasma allows for the potential realization of efficient nuclear fusion at low thermal energies kT≈10−20 eV. The study shows that these processes are linked to the formation of coherent correlated states of deuterons, accompanied by the generation of giant energy fluctuations δE≥10−50 keV during each recurring ionization event of deuterium atoms. These findings align with known anomalies in the solar atmosphere, such as the sharp temperature increase above the Sun’s surface and the observed excess concentration of helium-3 ions in the solar wind. Furthermore, this process may explain well-documented experimental results, such as neutron generation during electric discharges in gas.

Fluids with power-law repulsion: Hyperuniformity and energy fluctuations.

We revisit the equilibrium statistical mechanics of a classical fluid of point-like particles with repulsive power-law pair interactions, focusing on density and energy fluctuations at finite temperature. Such long-range interactions, decaying with inter-particle distance $r$ as $1/r^s$ in $d$ dimensions, are known to fall into two qualitatively different categories. For $s<d$ (``strongly" long-range interactions) there are screening of correlations and suppression of large-wavelength density fluctuations (hyperuniformity). These effects eliminate density modes with arbitrarily large energy. For $s>d$ (``weakly" long-range interactions) screening and hyperuniformity do not occur. Using scaling arguments, variational analysis, and Monte Carlo simulations, we find another qualitative distinction. For $s\geq d/2$ the strong repulsion at short distances leads to enhanced small-wavelength density fluctuations, decorrelating particle positions. This prevents indefinitely negative entropy and large energy fluctuations. The distinct behaviors for $s\geq d/2$ and $s<d/2$ give rise to qualitatively different dependencies of the entropy, heat capacity, and energy fluctuations on temperature and density. We investigate the effect of introducing an upper cutoff distance in the pair-potential. The effect of the cutoff on energy fluctuations is strong for $s<d/2$ and negligible for $s \geq d/2$.

Research on Changes in International Energy Trade Pattern under the Russia-Ukraine Conflict

The impact of the conflict between Russia and Ukraine on world energy markets has received great attention. Some researchers have found that the Russia-Ukraine conflict has caused an energy crisis to a certain extent. However, there is a lack of overview of the changes in the trade pattern and the scope of its impact. Therefore, through a comprehensive analysis of changes in policies and economic data, this study analyzes the different response measures taken by countries in different regions such as Europe and Asia to deal with the reduction in Russia's exports of major energy products and the fluctuations in international energy prices. This study also analyzes how the mutual sanctions between Russia and Western countries have contributed to the shift of Russia's energy export focus to the Asia-Pacific region and the diversification of Western countries' energy supply. Research results show that energy trade is at risk of being affected by geopolitical factors such as regional conflicts and mutual sanctions. The Russia-Ukraine conflict has strengthened the attention of countries on energy security issues. The research also highlights the implications for future policies and actions, providing an understanding of emerging trends in the future. Economically, this study, based on past data, emphasizes the inevitability of the Russia-Ukraine conflict affecting energy fluctuations and affirms that the Russia-Ukraine conflict is conducive to global new energy transformation and sustainable development in the long term.

Understanding energy fluctuation during the transition state: The role of AbrB in Bacillus licheniformis

BackgroundLimited research has been conducted on energy fluctuation during the transition state, despite the critical role of energy supply in microbial physiological metabolism.ResultsThis study aimed to investigate the regulatory function of transition state transcription factor AbrB on energy metabolism in Bacillus licheniformis WX-02. Firstly, the deletion of abrB was found to prolong the cell generation time, significantly reducing the intercellular ATP concentration and NADH/NAD+ ratio at the early stage. Subsequently, various target genes and transcription factors regulated by AbrB were identified through in vitro verification assays. Specifically, AbrB was shown to modulate energy metabolism by directly regulating the expression of genes pyk and pgk in substrate-level phosphorylation, as well as genes narK and narGHIJ associated with nitrate respiration. In terms of oxidative phosphorylation, AbrB not only directly regulated ATP generation genes, including cyd, atpB, hmp, ndh, qoxA and sdhC, but also influenced the expression of NAD-dependent enzymes and intracellular NADH/NAD+ ratio. Additionally, AbrB positively affected the expression of transcription factors CcpN, Fnr, Rex, and ResD involved in energy supply, while negatively affected the regulator CcpA. Overall, this study found that AbrB positively regulates both substrate-level phosphorylation and oxidative phosphorylation, while negatively regulating nitrate respiration.ConclusionsThis study proposes a comprehensive regulatory network of AbrB on energy metabolism in Bacillus, expanding the understanding of regulatory mechanisms of AbrB and elucidating energy fluctuations during the transition state.

Dynamics of Barred Coast at Different Temporal Scales (by the Example of Vistula Spit in the Baltic Sea)

According to fundamental concepts, the morphodynamic system of an accumulative sandy coast with underwater bars exhibits cyclic behavior across various time scales. This raises the question: which factor is more significant for the dynamics of a given coast—individual storms or seasonal changes in wave activity? While observations and studies addressing this issue have primarily been conducted on oceanic coasts, there is a lack of comparable data for fetch-limited areas. Monitoring of the bottom topography along the west coast of Vistula Spit (Baltic Sea) revealed a cyclic behavior in morphology, transitioning from a straightened external bar to its connection with the shore. Analysis of field measurement results indicated that seasonal variations in wave intensity do not significantly impact coastal relief. Furthermore, it was found that the complete cycle of underwater bar evolution lasts approximately two years, during which the coast profile maintains a stable shape at the stage of the straightened external bar. The identification of the primary factor influencing coastal evolution can be characterized by the Dean number (Ω), which combines wave parameters (wave height and period) with sediment fall velocity. Utilizing ERA5 wave reanalysis data, we compared the variability of Ω values on both annual and monthly scales. The analysis revealed that for the section of the coast under consideration, there is no clearly dominant evolutionary factor; rather, the coast is influenced approximately equally by individual storm events and seasonal fluctuations in wave energy. Modeling storm-induced bed profile deformations using the CROSS-PB model demonstrated that the position of the external underwater bar remains nearly constant even during intense and prolonged storms. It is concluded that under specific conditions—determined by a combination of sediment size, coastal slope, and wave regime characteristics—the coast can remain stable, exhibiting minimal response to relatively strong storms and seasonal variations in wave energy. Such coasts are characterized by an absence of a dominant evolutionary factor as indicated by fluctuations in the Dean parameter, allowing their morphodynamic cycles to span several seasons. This type of morphodynamics in coastal accumulative relief appears to be typical for conditions found in fetch-limited areas, such as regional and semi-closed seas.

Cooperative control strategy of variable evaporation temperature and variable superheat degree for a VRF system to improve temperature stability in multiple rooms

The energy consumption of variable refrigerant flow (VRF) systems can be reduced by adopting the variable evaporation temperature and constant superheat degree (VECS) control strategy instead of constant evaporation temperature and constant superheat degree (CECS) control strategy. However, the constant superheat degree control strategy may weaken the adjustment ability of cooling capacity of indoor units, and result in obvious room temperature fluctuations. In order to decrease room temperature fluctuations and reduce energy consumption simultaneously, a cooperative control strategy of variable evaporation temperature and variable superheat degree (VEVS) is proposed, i.e. one indoor unit is chosen to be controlled by variable evaporation temperature and the rest of the indoor units are controlled by variable superheat degrees. In this control strategy, the target value of evaporation temperature is the lowest value among the upper limits of the evaporation temperatures of all indoor units, and the target values of the superheat degrees of indoor units are predicted according to the cooling demands of rooms. Comparative experiments on room temperature fluctuation and energy consumption among the control strategies of CECS, VECS and VEVS are done. It is shown that both the control strategies of VECS and VEVS achieve smaller room temperature fluctuation and lower energy consumption than those of CECS; compared with the VECS control strategy, the average room temperature fluctuation of the VEVS control strategy is decreased from 1.1°C to 0.5°C due to variable superheat degree, and the energy consumption of the VEVS control strategy is reduced by 4.4%.

Zinc sulfide thin films produced by spray pyrolysis: optical and structural characteristics

Zinc sulfide thin films were prepared using the economical spray pyrolysis process. A thin film of exceptional quality with a temperature difference of 300 °C to 400 °C is produced by optimizing variables such as concentration, flow rate, and nozzle to substrate distance. These films' optical characteristics and structure were examined. The deposited thin films displayed a direct and allowed transition, as indicated by the optical transmittance spectra. XRD analysis confirmed that the deposited thin films were polycrystalline with a cubic phase. This film can be used in solar cell applications since the band gap energy fluctuation is high enough, ranging from 3.42 to 3.81 eV.

Diurnal Cycles of Cloud Properties and Precipitation Patterns over the Northeastern Tibetan Plateau During Summer

In the context of rising temperatures and increasing humidity in Northwest China, substantial gaps remain in understanding the mechanisms of land–atmosphere cloud–precipitation coupling across the northeastern Tibetan Plateau (TP), Loess Plateau (LP), and Huangshui Valley (HV). This study addresses these gaps by investigating cloud properties and precipitation patterns utilizing the Fengyun-4 Satellite Quantitative Precipitation Estimation Product (FY4A-QPE) and ERA5 datasets. We specifically focus on Lanzhou, a pivotal city within the LP, and Xining, which epitomizes the HV. Our findings reveal that diurnal variations in precipitation are significantly less pronounced in the eastern regions compared to northeastern TP. This discrepancy is attributed to marked diurnal fluctuations in convective available potential energy (CAPE) and wind shear between 200 and 500 hPa. While both cities share similar wind shear patterns and moisture transport directions, Xining benefits from enhanced snowmelt and effective water retention in surrounding mountains, resulting in higher precipitation levels. Conversely, Lanzhou suffers from moisture deficits, with dry, hot winds exacerbating the situation. Notably, precipitation in Xining is strongly correlated with CAPE, influenced by diurnal variability, and intensified by valley and lake–land breezes, which drive afternoon convection. In contrast, Lanzhou’s precipitation exhibits a weak relationship with CAPE, as even elevated values fail to generate significant cloud formation due to insufficient moisture. The ongoing trends of warming and humidification may lead to improved precipitation patterns, especially in the HV, with potential ecological benefits. However, concentrated rainfall during summer afternoons and midnights raises concerns regarding extreme weather events, highlighting the susceptibility of the HV to geological hazards. This research underscores the need to further explore the uncertainties inherent in precipitation dynamics in these regions.

Innovative solar-assisted direct contact membrane distillation system: Dynamic modeling and performance analysis

The study presents an innovative solar-assisted dual-tank direct contact membrane distillation (DCMD) system designed to enhance the operational stability and efficiency of solar-powered desalination. The proposed system integrates a dual thermal storage tank configuration, allowing for continuous operation by alternating between two tanks that store pre-heated water, thereby mitigating the impact of solar energy fluctuations. The dynamic modeling approach used in this study predicts the system's performance under varying solar conditions, focusing on key parameters such as permeate flux, evaporation efficiency, and specific thermal energy consumption. The simulation results show that the system achieves an average permeate flux of 14.4 L/h m² and a thermal efficiency of 53.3 % at a hot water temperature of 60 °C, with a corresponding average specific thermal energy consumption of 1567 kWh/m³. These findings highlight a substantial improvement in both thermal efficiency and water production compared to conventional single-tank systems.The dual-tank DCMD system is particularly suited for deployment in remote or arid regions where stable and efficient freshwater production is critical. This research provides a comprehensive analysis of a novel solar-assisted desalination technology, contributing to the advancement of sustainable water resources management by providing a reliable and scalable solution that can maintain high operational efficiency even in remote areas with variable solar conditions.

Riding the waves of investor sentiment: Cryptocurrency price and renewable energy volatility during the pandemic-war era

This study explores the interplay between cryptocurrency price volatility and renewable energy dynamics amid crises, particularly during the COVID-19 pandemic and the Russia-Ukraine conflict. Utilizing a Quantile Vector Autoregression (QVAR) model with daily data from April 1, 2015, to September 23, 2022, we assess the interconnectedness of cryptocurrency volatility, investor sentiment, and energy fluctuations. Our findings reveal a significant temporal variation in systemic connectedness influenced by recent global events. Overall, we observe approximately 30 % connectivity in the short run and 6 % in the long run. Notably, Bitcoin and the Fear and Greed Index shifted roles from net shock receivers to transmitters over various periods. Financial and macro uncertainties primarily acted as shock transmitters during 2017 to early 2022. Furthermore, investor sentiment transitioned from a shock transmitter before the pandemic to a shock receiver during it. The analysis underscores the substantial impact of extraordinary events e.g., the COVID-19 pandemic, the Russia-Ukraine conflict on market dynamics.

Enhancing energy control for a hybrid system comprising a wind turbine, diesel generator, and storage systems

The increase in demand for electrical energy has made renewable energy sources, such as wind power, increasingly attractive. However, intermittency and variability represent the major problems of these types of energies. The hybridization of several energy sources allows to have a reliable and efficient supply system. This paper was interested in the control of a hybrid energy system, which includes a wind turbine, storage systems (batteries and super-capacitors) and a conventional diesel generator, with the aim of generating constant power. A control strategy is developed taking into account the various constraints of the hybrid system. Both of storage systems as well as the diesel generator operate according to the modes presented in the supervision algorithm to absorb and compensate the fluctuation of the wind energy and reach to a constant energy flow. The super-capacitor operates before the battery to absorb the power peaks in both charge and discharge modes. The hybrid system is simulated using MATLAB/Simulink software, and the results are provided in order to show the effectiveness of this control strategy.

Large-eddy simulation of tip clearance cavitating flow around a hydrofoil

Large-eddy simulations of tip clearance cavitating flow between a National Advisory Committee for Aeronautics 0012 hydrofoil and the endwall have been performed to investigate the effects of cavitation on vortical structures, turbulence statistics and hydrofoil performance within the tip clearance region. The wall-adapting local eddy-viscosity model is employed to compute the subgrid-scale stress, and the Zwart-Gerber-Belamri cavitation model is used to predict the cavitating flow. The simulation results show that cavitation has insignificant effects on the tip clearance flow structures and the wandering motion of the tip leakage vortex (TLV). Detailed analysis of turbulence statistics indicates that the turbulent kinetic energy and pressure fluctuation inside the TLV core are significantly increased under the effect of cavitation. In addition, it is found that cavitation enhances the unstable wall-normal motion of the TLV, leading to the enhancement of turbulence near the TLV core. The hydrofoil performance affected by cavitation is also investigated, showing that the lift and drag forces acting on the hydrofoil is substantially reduced due to the cavitation.

Transition state of matter in the fluctuation model of crystal growth

Two mechanisms of the effect of the transition state of building particles (activated complexes according to S. Arrhenius) on the crystal growth rate within the framework of the fluctuation model of dislocation crystal growth are discussed. Transition state clusters adsorbed on the surface of the growing face perform the function of an impurity that lowers the surface energy of the crystal at the time moments between free energy fluctuations. Thus, the transition state of the crystallizing substance by the first mechanism affects the relaxation rate of the secondary adsorption of impurities and shortens the time period of attachment of building particles to the crystal face. Other clusters formed in solution reduce the number of free particles and under conditions of low concentration of the building substance are able to decrease the crystallization rate. Nevertheless, in a natural multicomponent crystallization environment, at low concentrations of building material, significant thermal effect of crystallization and small deviations from equilibrium, the role of the transition state in crystal growth is generally insignificant.

An Enhanced Edge Computing Technique for Detection of Voltage Fluctuation in Grid-tied Renewable Energy

Renewable energy sources (RES) such as solar photovoltaic and wind are becoming the most attractive power generation options in many nations. Even while high penetration seems likely, power quality anomalies such as voltage fluctuation, harmonics, and frequency fluctuation associated with RES hinder seamless integration. The variability and unpredictability of these sources create the most oddities. In grid-tied renewable energy, monitoring power quality efficiently is crucial. Power grid monitoring solutions in related literature use sensor-based cloud and edge computing techniques. The existing systems struggle with excessive latency when delivering large amounts of generated data to the cloud. To fill this gap, a new approach for the detection and localization of voltage fluctuation is proposed in this study. The approach integrated three techniques namely; feed-forward neural network (FFNN), Stockwell transform, and anomaly-aware edge computing to detect and locate voltage fluctuation in a GtRE. Using MATLAB/Simulink, virtual emulation of a modified IEEE 33 Bus and a GtRE representing a section of Ado Ekiti (in Nigeria) low-voltage distribution grid are carried out for data generation and system evaluation. Feature extraction was carried out in a Python IDE using Stockwell transform. The voltage fluctuation events are detected and localized based on the extracted features using the trained FFNN model deployed and evaluated within three microcontroller-based computing devices. The proposed approach integrated anomaly-aware with edge computing to send only voltage data that are considered abnormal to a dedicated data center for visualization and storage. Performance evaluation of the proposed technique on the simulated GtRE demonstrates a significant decrease of 98% and 90% in latency when compared to cloud computing and conventional edge computing respectively. Comparison of the proposed approach to two closely related solutions in literature also demonstrates a 50% and 92.5 % reduction in latency. The contribution of the study is the reduced latency and minimal bandwidth utilization achieved by the implementation of the developed technique.

Scaling properties of (2+1) directed polymers in the low-temperature limit

Abstract In terms of the replica method, we consider the low-temperature limit of (2+1) directed polymers in a random potential. The proposed approach allows us to compute the scaling exponent θ of the free energy fluctuations as well as the left tail of its probability distribution function. It is argued that θ = 1 / 4 , which is slightly different to the zero-temperature numerical value that is close to 0.241.

Correction to: Free Energy Fluctuations of the Bipartite Spherical SK Model at Critical Temperature

Correction to: Free Energy Fluctuations of the Bipartite Spherical SK Model at Critical Temperature

Transactive energy management for CIES considering tri-level hybrid game-theoretic approaches with multiple weight allocation factors

In city integrated energy systems, to reduce the costs of energy production and usage, it is extremely important for different entities to design proper energy management approaches since they have diverse behaviours and benefits. The hierarchy of the system is naturally divided into three layers, and hybrid game theories are employed on the basis of the vertical master–slave and horizontal equal cooperation characteristics among energy providers, aggregators, and users. First, to reflect the interactions between different levels' entities, Stackelberg game theory is adopted vertically, and the model complexity is lessened by the KKT conditions. Then, for energy providers, the asymmetric bargaining game is improved by combining multiple weight allocation factors, which can help reduce renewable energy fluctuations and encourage the consumption of clean energy to reduce the carbon emissions of the system. Also, the results show that the proposed method can enhance the utility of renewable energy generation units by approximately 64 % to 69 %. Finally, the optimality and effectiveness of the proposed game theoretic approaches are verified in case studies and in strict mathematical proofs. In addition, the impact mechanisms on the demand response from the perspectives of the user load and price sensitivity are analysed. To explore pricing methods that are more suitable for user aggregators, two pricing strategies are designed for the user aggregator and compared in terms of computation time and revenue. The results show that a unified pricing strategy can increase the aggregator's revenue by 1.24 % and reduce the computation time by 24.47 %.

Energy management strategy and operation strategy of hybrid energy storage system to improve AGC performance of thermal power units

With the continuous increase of the renewable energy power generation penetration, the intermittency and fluctuation of renewable energy power generation make the traditional thermal power units (TPU) which play the main role of regulation need to undertake more frequent and more severe regulation tasks. In order to improve the automatic generation control (AGC) command response capability of TPU, an operation strategy of hybrid energy storage system (HESS) is proposed in this paper. While assisting TPU to complete the regulation tasks, it gives full play to the advantages of power-type and energy-type energy storage. Moreover, an energy management strategy of energy storage array (ESA) is proposed to improve the overall operation efficiency of ESA while making the state of charge (SOC) of all energy storage subunits consistent. Finally, the effectiveness of the proposed strategy is verified by simulation experiments. The results show that after using HESS to assist TPU operation, the comprehensive regulation performance index of TPU increased from 4.0198 to 7.8112, which significantly improved the operational flexibility of TPU. Meanwhile, the strategy proposed in this paper makes different types of energy storage systems in HESS operate in a relatively healthy SOC range, and the SOC of the flywheel energy storage system (FESS) reaches the limitation value decrease from 6 times to once, ensuring the overall charge and discharge capacity of HESS.

Flow state transition induced by emergence of orbiting satellite eddies in two-dimensional turbulent Rayleigh–Bénard convection

We report a numerical investigation of a previously noticed but less explored flow state transition in two-dimensional turbulent Rayleigh–Bénard convection. The simulations are performed in a square domain over a Rayleigh number range of $10^7 \leq Ra \leq 2 \times 10^{11}$ and a Prandtl number range of $0.25 \leq Pr \leq 20$ . The transition is characterized by the emergence of multiple satellite eddies with increasing $Ra$ , which orbit around and interact with the main vortex roll in the system. Consequently, the main roll is squeezed to a smaller size compared with the domain and wanders around in the bulk region irregularly and extensively. This is in sharp contrast to the flow state before the transition, which is featured by a domain-sized circulatory roll with its vortex centre ‘condensed’ near the domain's centre. Detailed velocity field analysis reveals that there exists an abrupt increase in the energy fluctuations of the Fourier modes during the transition. Based on this phase-transition-like signal, the critical condition for the transition is found to follow a scaling relation as $Ra_t \sim Pr^{1.41}$ where $Ra_t$ is the critical Rayleigh number for the transition. This scaling relation is quantitatively explained by a phenomenological model grounded on the bistability behaviour (i.e. spontaneous and stochastic switching between the two flow states) observed at the edge of the transition. The model can also account for the effects of aspect ratio on the transition reported in the literature (van der Poel et al., Phys. Fluids, vol. 24, 2012).