Sudden Energy Research Articles

Computational Optimization of CFRP Strip Thickness for Enhanced Blast Mitigation in Structural Pipe Retrofitting

Abstract Explosions, characterized by sudden energy releases and destructive shock waves, are increasingly frequent due to terrorism, industrial accidents, and infrastructure decay. These events pose serious risks to pipelines, causing leaks, disruptions in services, and environmental damage, highlighting the urgent need for robust mitigation strategies. The aim of this study is to explore the efficacy of CFRP strips in augmenting a pipe’s response to contact blast loads. Advanced 3D simulations of blast wave interactions with an empty pipe were conducted using computational fluid dynamics techniques. These simulations were complemented by comparative analyses using Abaqus, benchmarked against existing literature findings after rigorous validation. Subsequently, the research expanded to optimize the computational assessment of CFRP strip thicknesses for enhancing blast mitigation in structural pipe retrofitting. The authors systematically varied strip thicknesses from 0.15mm to 0.75mm in uniform increments of 0.15mm, evaluating their respective performances and comparing the results. Results showed that: CFRP strips significantly reduce pipe deformation under blast loading, with thicker strips, particularly at 0.75mm, demonstrating the highest effectiveness in enhancing blast resistance and minimizing severe damages.

Modelling unstable crack propagation in concrete by finite element method with continuous nodal stress

Cracks in concrete will propagate unstably due to excessive shear stress, interactions at the rock-concrete interface, or sudden energy release, significantly compromising structural bearing capacity. To investigate this phenomenon, a nonlinear numerical method for modelling mixed-mode I-II crack propagation has been developed. This approach integrates dynamic equilibrium with a fictitious crack model and an initiation fracture toughness criterion. Key innovations include the incorporation of a finite element method with continuous nodal stress to enhance calculation accuracy, the utilization of kinetic energy to compensate for abrupt losses of strain energy during crack propagation, and the consideration of the deformation of the distributive beam and its interactions with specimens and supports. It was validated by modelling classic benchmarks for the dynamic initiation and propagation of brittle materials under mode I and mixed-mode I-II loading, and applied to analyse unstable crack propagation in concrete for four-point shear (FPS) beam specimens under various ratios of mode I and II stress intensity factors (KI/KII = 0 to 5.32) and loading rates (2 × 10-7 m/s to 2 × 10-3 m/s). Results indicated that the method effectively captures unstable crack propagation, with load-crack mouth shear displacement (CMSD) curves and crack propagation trajectories closely matching the experimental data. Furthermore, it was observed that when the elastic strain energy within the concrete beam exceeds the residual energy stored in the extended cracks, the crack transitions from stability to instability; conversely, if the elastic strain energy is less than or approximately equal to the residual energy, the crack decelerates and returns to stability. Additionally, parametric analyses reveal that lower distributive beam stiffness, shorter preset crack lengths, reduced concrete fracture energy, and a less robust cohesive force–displacement curve increase the likelihood of unstable crack propagation in concrete.

EOS: Impact Evaluation of Electric Vehicle Adoption on Peak Load Shaving Using Agent-Based Modeling

The increasing adoption of electric vehicles (EVs) by the general population creates an opportunity to deploy the energy storage capability of EVs for performing peak energy shaving in their households and ultimately in their neighborhood grid during surging demand. However, the impact of the adoption rate in a neighborhood might be counterbalanced by the energy demand of EVs during off-peak hours. Therefore, achieving optimal peak energy shaving is a product of a sensitive balancing process that depends on the EV adoption rate. In this paper, we propose EOS, an agent-based simulation model, to represent independent household energy usage and estimate the real-time neighborhood energy consumption and peak shaving energy amount of a neighborhood. This study uses Residential Energy Consumption Survey (RECS) and the American Time Use Survey (ATUS) data to model realistic real-time household energy use. We evaluate the impact of the EV adoption rates of a neighborhood on performing energy peak shaving during sudden energy surges. Our findings reveal these trade-offs and, specifically, a reduction of up to 30% of the peak neighborhood energy usage for the optimal neighborhood EV adoption rate in a 1089 household neighborhood.

Mass Ejection Driven by Sudden Energy Deposition in Stellar Envelopes

A number of stellar astrophysical phenomena, such as tidal novae and planetary engulfment, involve sudden injection of subbinding energy in a thin layer within the star, leading to mass ejection of the stellar envelope. We use a 1D hydrodynamical model to survey the stellar response and mass loss for various amounts (E dep) and locations of the energy deposition. We find that the total mass ejection has a nontrivial dependence on E dep due to the varying strengths of mass ejection events, which are associated with density/pressure waves breaking out from the stellar surface. The rapid occurrence of multiple breakouts may present a unique observational signature for sudden envelope heating events in stars.

Classification and Application Development of Hedge Energy Dissipators

At present, most of China's oilfield mining using high-pressure fracturing and other methods, in the oilfield mining and subsequent pipeline transport are accompanied by a large amount of pressure and energy, the mining and pipeline transport equipment to produce a lot of wear and tear and hazards, so it is necessary to install pressure reduction and dissipation device. In the past, most of the sudden expansion and contraction of the energy loss generated by the pressure reduction and energy dissipation device. After continuous research by scholars, it is proposed to use the energy dissipation of the fluid between the pressure reduction and energy dissipation device, which has a higher stability, and can improve the efficiency of its energy dissipation. In this paper, the classification and research on the classification of the sudden expansion and contraction energy dissipation structure, the classification, optimal design and the application development of the hedge type energy dissipation structure in the field of petroleum industry are discussed, and some outlooks and suggestions are put forward for the research and development of the hedge type energy dissipation device in the future.

Dynamics of baryon ejection in magnetar giant flares: implications for radio afterglows, r-process nucleosynthesis, and fast radio bursts

ABSTRACT We explore the impact of a magnetar giant flare (GF) on the neutron star (NS) crust, and the associated baryon mass ejection. We consider that sudden magnetic energy dissipation creates a thin high-pressure shell above a portion of the NS surface, which drives a relativistic shockwave into the crust, heating a fraction of these layers sufficiently to become unbound along directions unconfined by the magnetic field. We explore this process using spherically symmetric relativistic hydrodynamical simulations. For an initial shell pressure PGF we find the total unbound ejecta mass roughly obeys the relation $M_{\rm {ej}}\sim 4\!-\!9\times 10^{24}\, \rm {g}\, (P_{\rm GF}/10^{30}\, \rm {erg}\, \rm {cm}^{-3})^{1.43}$. For $P_{\rm {GF}}\sim 10^{30}\!-\!10^{31}\, \rm {erg}\, \rm {cm}^{-3}$ corresponding to the dissipation of a magnetic field of strength $\sim 10^{15.5}\!-\!10^{16}\, \rm {G}$, we find $M_{\rm {ej}}\sim 10^{25}\!-\!10^{26}\, \rm {g}$ with asymptotic velocities vej/c ∼ 0.3–0.6 compatible with the ejecta properties inferred from the afterglow of the 2004 December GF from SGR 1806-20. Because the flare excavates crustal material to a depth characterized by an electron fraction Ye ≈ 0.40–0.46, and is ejected with high entropy and rapid expansion time-scale, the conditions are met for heavy element r-process nucleosynthesis via the alpha-rich freeze-out mechanism. Given an energetic GF rate of roughly once per century in the Milky Way, we find that magnetar GFs could be an appreciable heavy r-process source that tracks star formation. We predict that GFs are accompanied by short ∼minutes long, luminous $\sim 10^{39}\, \rm {erg}\, \rm {s}^{-1}$ optical transients powered by r-process decay (nova brevis), akin to scaled-down kilonovae. Our findings also have implications for the synchrotron nebulae surrounding some repeating fast radio burst sources.

Simulations of a possible configuration of Premium Power Park

The voltage dip and the sudden electrical energy interruption are, probably, the most important disturbances of the power quality in the electrical system. Several technical solutions exist to mitigate voltage dips, respectively at plant or system level as for example: • the installation of Custom Power (CUSPO) for a single customer; • the Premium Power Park (PPP) for a group of customers. According to the PPP concept, the tenants of an industrial or commercial office park would be provided with a guaranteed level of electrical service quality made possible by Custom Power devices, such as the Dynamic Voltage Restorer (DVR), the Distribution Static Compensator (DSTATCOM – Distribution STATCOM), the medium voltage Static Transfer Switch (STS). The paper summarizes the Premium Power Park idea and a possible configuration of it, studied by ERSE, including the system aspects and the analysis of the combined operation or interaction of the Custom Power.

The management of power supply security of mine water pumping station

Purpose: Growing global warming increases the threat of energy supply security in the form of the “blackout” phenomenon. Pumping stations pump out approximately 100 million m3 of water annually (data from 2023). Discontinuation of mine water pumping would expose neighbouring mines and lower-lying areas to flooding. Design/methodology/approach: For the designed database of functional scenarios of the mine water pumping station, the optimal variant was selected based on economic and ecological criteria as well as the energy security criterion. Findings: The research analyzed five technically feasible variants of modernization of mine water pumping stations. Each variant is characterized by a different degree of security of energy supply and a different level of meeting energy demand. Research limitations/implications: All variants of modernization of the pumping station provide for the production of electricity for own needs. All investment attractiveness factors should be taken into account while making investment decisions. It is up to the decision-maker to make the final multi-criteria decision so as to implement the selected variant. Practical implications: One of the challenge is to ensure security of energy supplies in the event of a sudden energy shortage. Pumping stations have some retention, nevertheless a longer shutdown time could lead to environmental problems. Removing the damage would definitely require large financial expenditures and would take several years. Social implications: The planned project of the energy supply security can have a positive impact on the local community and economy. The projects discussed will create new markets related to "green energy". Originality/value: The aim of the article is to assess the investment relevance of safety projects for power supply to mine water pumping stations. The combination of the problems of drainage of liquidated mines, the use of renewable energy sources and energy storage to improve the security of power supply to pumping stations has not been the subject of scientific research so far. Keywords: drainage of liquidated mines, energy storage, renewable sources of energy, hydrogen extraction, revitalization of post-mining installations. Category of the paper: Research paper, conceptual paper, case study

A semi-empirical model for magnetic storm dynamics

The near-Earth electromagnetic environment represents a far-from-equilibrium system characterized by sudden irregular energy relaxation events. For a broad class of complex systems, time series can be interpreted in terms of a superposition of stochastic and deterministic components occurring at different time scales. In this work we use the generalization of the SYM-H index provided by the SuperMAG collaboration (SMR), which is meant for monitoring the global variation of the horizontal component of the Earth’s magnetic field in the near-equatorial regions. The aim of this work is to model the SMR dynamics via stochastic differential equations thus providing a semi-empirical model whose parameters are retained from data. As a first step we test the Markov condition on the SMR data sample, which represents the basic condition for our stochastic modeling, and we show that such a requirement is accurately satisfied by SMR time series. This allows us to infer the model parameters for the SMR index through the Kramers–Moyal analysis. Finally, we give evidence that a purely diffusive process is not representative of the observed dynamics and then a model based on jump-diffusion processes must be considered to correctly reproduce the dynamical features of the SMR index.

Removing abnormal environmental noise in nodal land seismic data using deep learning

In field seismic data, abnormal environmental noise from the acquisition environment often is unavoidable, and its characteristics are complex. Abnormal environmental noise has a strong amplitude (tens of thousands times the average seismic amplitudes) and masks the effective seismic signal. The traditional method for removing such abnormal environmental noise relies on energy scanning to identify the noise location. However, energy scanning cannot always accurately identify such noise due to the sudden energy change at the locations of first-breaks and surface waves. A deep learning method for removing abnormal environmental noise has been developed. The presence of environmental noise with large amplitude also results in an uneven energy distribution. The existing denoising networks rarely consider this situation. Based on the characteristics of environmental noise received by the nodal seismic acquisition system, a workflow for automatically generating the training data sets has been established. The network is built based on the Unet with the incorporation of a residual block. The Batchnorm layer is specifically omitted to adapt to the uneven energy distribution. Synthetic and field data testing have confirmed the effectiveness and applicability of the proposed method. The new method indicates better denoising performance and greater flexibility than the traditional method. Comparison between different networks also indicates that the new Residual Block Connected Unet is much more effective in denoising seismic data that contain abnormal environmental noise.

Occam’s razor description of sudden energy transitions in a Rabi-driven quantum bit under frequent observation

Occam’s razor description of sudden energy transitions in a Rabi-driven quantum bit under frequent observation

Synthetic Resilience Exploration and Economic Defense Strategy for Microgrid-Level AC/DC Hybrid Energy System

For the ac/dc hybrid energy system, a resilience-oriented defense strategy is developed for survivability enhancement when subject to severe energy disruptions. On account of heterogeneous components, an integration index of synthetic resilience (SR) is formulated to assess the resilience capability of hybrid energy systems in the event of sudden energy changes. The derived SR is systematically illustrated in this work, which not only reveals its convexity feature but also visualizes the inherent self-healing resources during the ac/dc energy interaction. Based on the proposed resilience index and interlinking bridge of bidirectional converter, an economic defense strategy concerning uncertainties from renewable energies and loads is developed and system resilience is consequently reinforced by dispatching distributed energies according to individual marginal cost. Without the global coordination and mode transition, the system resilience is significantly strengthened and assessed by the proposed index and defense strategy, which formulates an operational paradigm for the microgrid-level energy hybridization considering load variation and renewable energy penetration. To completely demonstrate the effectiveness of the proposed index and defense strategy for the hybrid energy system, the controller-hardware-in-the-loop experiment results have been provided from six aspects of steady-state operation, dc demand variation, ac demand variation, renewable energy fluctuations, dc energy source failure, and ac energy source failure.

Minimum ignition energy of hydrogen–ammonia blends in air

We present a numerical analysis to calculate the minimum ignition energy of hydrogen–ammonia blends in air at both under and over atmospheric pressure. Unlike previous calculations, we used the full compressible and reactive Navier–Stokes equations coupled with detailed chemical kinetics (San Diego mechanism for hydrogen, complemented with the San Diego chemistry for nitrogen). The effect of the size of the energy deposition region and the deposition time are considered to determine the most efficient method to ignite the mixture. Our calculations also evaluate the impact of the gas compressibility on the minimum ignition energy after a sudden energy deposition. The results are validated first by comparing the minimum ignition energy of pure hydrogen–air mixtures as a function of the equivalence ratio ϕ with available experimental data and previous numerical results. Then, fuel blends made of mixtures of hydrogen and ammonia (NH3) are considered to calculate the minimum ignition energy as a function of fuel composition, equivalence ratio and pressure. The full range of ammonia volumetric content in the blend is varied between the extreme cases of pure hydrogen and pure ammonia. For each fuel blend, we computed a wide range of equivalence ratios ϕ that, in the case of pure hydrogen at atmospheric conditions, ranged from ϕ=7 to ϕ≃0.07, near the lean flammability limit, to theoretically explain the experimental evidence of ultra-lean flames reported in the literature.

Contributing factors in initiation of debris flow in Malaysia

Debris flow caused high number of deaths among many of geohazard events in Malaysia due to the characteristics of sudden outburst and high energy density. This paper reviewed the initial mechanism and characteristics of existing debris flow in Malaysia. Almost all debris flows occurrence were initiated on natural terrains as opposed to other forms of landslides. Most of the events were induced by the rainfall. This is due to the geographic locations of Malaysia that lies on the equator with tropical climates and received abundant rainfall of 2400 mm annually. Intense and heavy rainfall increases the water content and pore water pressures within the residual soil that could trigger landslides. Thus, an intense and prolonged rainfall has become the major triggering factor for debris flow. This review article focus on clarifies the characterization of historical debris flow events that had an impact the infrastructure in Malaysia. In summary, this review attempts to systematically summarize the existing research on the mechanism of debris flow in Malaysia to provide further reference on debris flow prevention. Comprehensive understanding of the mechanisms and the behaviour of the debris flow will assist to the fundamental hazard and provide proper planning for structural measures.

An explicit predictor/multicorrector time marching with automatic adaptivity for finite-strain elastodynamics

We propose a time-adaptive predictor/multi-corrector method to solve hyperbolic partial differential equations, based on the generalized-α scheme that provides user-control on the numerical dissipation and second-order accuracy in time. Our time adaptivity uses an error estimation that exploits the recursive structure of the variable updates. The predictor/multicorrector method explicitly updates the equation system but computes the residual of the system implicitly. We analyze the method's stability and describe how to determine the parameters that ensure high-frequency dissipation and accurate low-frequency approximation. Subsequently, we solve a linear wave equation, followed by non-linear finite strain deformation problems with different boundary conditions. Thus, our method is a straightforward, stable and computationally efficient approach to simulate real-world engineering problems. Finally, to show the performance of our method, we provide several numerical examples in two and three dimensions. These challenging tests demonstrate that our predictor/multicorrector scheme dynamically adapts to sudden energy releases in the system, capturing impacts and boundary shocks. The method efficiently and stably solves dynamic equations with consistent and under-integrated mass matrices conserving the linear and angular momenta as well as the system's energy for long-integration times.

OpenFOAMTM Simulation of the Shock Wave Reflection in Unsteady Flow

This work studies the impact of a shock wave traveling with non-constant velocity over straight surfaces, generating an unsteady and complex reflection process. Two types of shock waves generated by sudden energy released are studied: cylindrical and spherical. Several numerical tests were developed considering different distances between the shock wave origin and the reflecting surface. The Kurganov, Noelle, and Petrova (KNP) scheme implemented in the rhoCentralFoam solver of the OpenFOAMTM software is used to reproduce the different shock wave reflections and their transitions. The numerical simulations of the reflected angle, Mach number of the shock wave, and position of the triple point are compared with pseudo-steady theory numerical and experimental studies. The numerical results show good accuracy for the reflected angle and minor differences for the Mach number. However, the triple point position is more difficult to predict. The KNP scheme in the form used in this work demonstrates the ability to capture the phenomena involved in the unsteady reflections.

Time-dependent condensation of bosonic potassium

We calculate the time-dependent formation of Bose–Einstein condensates (BECs) in potassium vapours based on a previously derived exactly solvable nonlinear boson diffusion equation (NBDE). Thermalization following a sudden energy quench from an initial temperature T_mathrm {i} to a final temperature T_mathrm {f} below the critical value and BEC formation are accounted for using closed-form analytical solutions of the NBDE. The time-dependent condensate fraction is compared with available ^{39}K data for various scattering lengths.Graphic

Spoke-resolved electron density, temperature and potential in direct current magnetron sputtering and HiPIMS discharges

Spokes are long wavelength oscillations observed in the magnetized region of direct current magnetron sputtering (DCMS), high power impulse magnetron sputtering (HiPIMS), as well as other discharges. Spokes rotate in front of the cathode with velocities between about 2 km s−1 and 15 km s−1, making it difficult to perform quantitative measurements. This is overcome by synchronizing Langmuir probe measurements to the movement of spokes in DCMS to obtain the probe current–voltage (I–V) characteristic without averaging out the spoke influence. The I–V curves are then evaluated using magnetized probe theory, revealing the strong plasma parameter modulations, caused by the spokes. The plasma density was found to oscillate between 2.5 × 1016 m−3 and 1.7 × 1017 m−3, which corresponds to a modulation strength of more than 70% or an almost seven times increase of density. In good agreement with previous work, a plasma potential minimum of −55 V is found ahead of the spoke followed by a sudden increase to about 2 V inside the spoke. The electron temperature was found to oscillate between 3 eV and 7 eV. On top of that oscillation, electrons experience a sudden energy increase as they move inside the spoke, crossing the potential jump at the leading edge for the spoke. On basis of these observations a model is presented to explain spokes in DCMS. These results are then compared to HiPIMS spokes under otherwise similar conditions. The plasma parameter modulation found for HiPIMS is much weaker than for DCMS, which is explained by the higher collision frequency for electrons in HiPIMS plasmas.

Temporal-spatial characterization of mining-induced seismicity in the vicinity of a dyke – A case study

Major faults and dykes are common geological discontinuities in underground mines and can often contribute to significant failures such as coal bursts during mining. The failure mechanisms of faults have been widely studied, whereas the seismic characteristics associated with dykes have been rarely investigated for mine dynamic hazard risk management. This research aimed to characterize the seismic behavior near an intrusive dyke that intersected with the roadways in an underground longwall coal mine in Australia. The temporal-spatial variations of seismic multi-parameters around the stiff dyke were analyzed, including clustered seismicity, event locations, Es/Ep ratio, b-value and correlation with the released seismic energy. Four stages were defined based on the evolutions of seismic characteristics. The rock fractures initiated near the dyke when the longwall face was 400 m from the dyke. The seismicity started to increase when the longwall was <100 m from the dyke and decreased drastically after the longwall mined 50 m past the dyke. The seismic events were concentrated at the inbye side of the dyke and propagated to the outbye side of the dyke as the longwall mined through the dyke. The spatial distribution of Es/Ep ratios and temporal variations of the b-value indicated that higher magnitude seismic events dominated by shear failures occurred in the hanging wall of the dyke, suggesting more sudden seismic energy release and escalating seismic risks around the roadways at the inbye side of the dyke. Meanwhile, when the longwall was mining through the dyke, even though the seismicity was intensive, seismic energy was more frequently and gently released so that stress was not significantly accumulated to induce any major failures at the outbye side of the dyke. The results demonstrated that the geological features of the dyke and the longwall mining progress had a controlling effect on the seismic characteristics in the time-space domain. The comprehensive analysis of seismic multi-parameters reliably revealed the rock mass response near a major dyke and can provide guidance for assessing and managing the risks of dynamic mining hazards around dykes.

Machine-learning Algorithms Based on Time-series Data for Real-time Classification of Nuclear Fusion Plasmas in KSTAR

A high confinement mode (H-mode)1) was selected as one of the basic operation scenarios of ITER.2) The H-mode is a phenomenon in which the plasma confinement performance suddenly increases because a transport barrier is formed near the plasma boundary. However, although there are advantages obtained in the H-mode, instabilities at the plasma boundary also appear, such as edge localized modes (ELMs). The problem with the ELMs is that the transport barrier periodically collapses (ELM crash). As a result, high temperature energy and particles are released, damaging the plasma-facing components. Therefore, various studies for controlling the ELMs are continuously conducted in various tokamak devices worldwide. The most effective method to prevent ELM crashes is resonant magnetic perturbation (RMP). Also, the most problematic phenomenon among various instability phenomena of plasma, including the ELMs, is plasma disruption.3) The disruption is a phenomenon in which the plasma inside the tokamak loses heat and electromagnetic energy very quickly and disappears. This sudden energy loss induces a considerable heat flux to the plasma-facing components. Furthermore, it applies a strong electromagnetic force to the surrounding conductor to damage the tokamak device, so it is an unstable phenomenon that must be resolved.