Energy Accumulation Research Articles

General limit to thermodynamic annealing performance.

Annealing has proven highly successful in finding minima in a cost landscape. Yet, depending on the landscape, systems often converge towards local minima rather than global ones. In this Letter, we analyze the conditions for which annealing is approximately successful in finite time. We connect annealing to stochastic thermodynamics to derive a general bound on the distance between the system state at the end of the annealing and the ground state of the landscape. This distance depends on the amount of state updates of the system and the accumulation of nonequilibrium energy, two protocol and energy landscape-dependent quantities which we show are in a trade-off relation. We describe how to bound the two quantities both analytically and physically. This offers a general approach to assess the performance of annealing from accessible parameters, both for simulated and physical implementations.

Non-local three phase lag bio thermal modeling of skin tissue and experimental evaluation

In this paper, the thermal behavior of living tissue has been modeled using a non-local three-phase lag approach. The simulation results of this model- ing have been compared with experimental results of alternating radiation with different periods on human skin, yielding satisfactory alignments. Ad- ditionally, it has been investigated that the TPL model, which is an equation with an integral term, can simulate energy accumulation within the dermal tissue. Moreover, the non-local nature of the modeling has been explored to alter the influence of phase lag terms. Furthermore, apart from numer- ically solving the equation, an analytical solution has been derived for the frequency equation, demonstrating the effects of simulation parameters on the frequency equation and simulation results. The obtained results indi cate that these parameters not only independently affect the outcomes but also interact with other parameters, leading to variations beyond their direct impacts.

Analysis of energy dissipation characteristics and numerical simulation of surrounding rock control for backfill combinations with different ash/sand ratios

To reduce the economic cost of backfilling a mine, layers of cemented materials with different ash sand ratios are often used to backfill the void. In this study, we explored the damage evolution mechanism from the energy consumption point of view for backfill and rock combination with different ash sand ratios, and introduced the strength dissipation rate, damage value parameter and elastic strain energy rate to achieve the definition of damage in the specimens, as well as the characterization of the energy accumulation effect. In addition, the layered backfilling of the assemblage was simulated using FLAC 3D software. The results show that: (1) the elastic strain energy rate can reflect the accumulation ability of the strain energy of the specimen; the larger the strain energy rate, the stronger the accumulation ability; (2) the damage evolution of the backfill–backfill combination is divided into stages: initial damage repair stage, damage stable development stage, damage accelerated development stage and residual damage stage; and (3) the top layer with an ash/sand ratio of 1:4, the middle layer with an ash/sand ratio of 1:8 and the bottom layer with an ash/sand ratio of 1:10 is the optimal backfilling scheme. This study can provide a theoretical reference for the backfilling of a hollow area.

ANALYSIS OF ENERGY EXCHANGE PROCESSES WHEN BALANCING REGIMES ENERGY SUPPLY SYSTEMS WITH DISTRIBUTED GENERATION

It is shown that maintaining a balance between the production and consumption of electric energy is an important condition for the stable operation of modern energy supply systems. The active increase in the share of renewable energy sources forces the use of new algorithms for balancing demand and supply, in particular, at the expense of flexibility. This implies the need to implement new technological solutions and approaches to balancing the modes of generation and consumption (the ability to quickly respond to changes in demand and supply), which, in turn, requires a detailed analysis of energy exchange processes in electric power systems.
 It is recognized that there is a need for an in-depth analysis of the balance of energy components, and an assessment of electromagnetic compatibility in electric power systems, especially in the conditions of the growing influence of renewable energy sources on local electricity markets. Analysis of various factors influencing technological solutions and cooperation of different market parties are key components for developing effective management strategies and ensuring the stability of the electric power system.
 The peculiarities of the analysis of energy exchange processes in local electric power systems with the determination of exchange capacities, which are integral characteristics of the influence of various factors of the non-acidity of electricity on exchange processes, are considered. It is proposed to balance the components of electric energy on the basis of exchange processes in controlled intersections of local electric power systems using the components of instantaneous power at each energetically constant state. The exchange processes in local electric power systems are analyzed with the selection of different modes of their operation, in particular, when assessing the level of electromagnetic compatibility of the elements of the local electric power systems.
 The introduction of exchange capacities made it possible to develop indicators for assessing the level of electromagnetic compatibility of the elements of the local system. To estimate the share of consumers' contribution to the deterioration of the quality of electricity at the common connection point, an algorithm for evaluating the mutual influence of elements is proposed, with the allocation of the element's contribution to the distortion of electricity in the controlled intersection and the analysis of the magnitude of the influence of distorting factors on electromagnetic processes in the system element.
 An optimization model for achieving the specified levels of balancing (flexibility) in local electric power systems with energy accumulators has been developed.

Study on the Stress Evolution and Strengthening Support Timing of the Retracement Channel under the Super-Thick Nappe

The superposition effect of the advanced support pressure of the working face in the final mining stage and the lateral support stress of the roadway is a key factor affecting the stability of the retracement channel. To study the stress evolution of the retracement channel under the super-thick nappe and the timing of strengthening support, this paper takes the mining of the 360808 working face in Xinji No. 1 Mine as the engineering background, analyzes the occurrence conditions of the working face and the measured rock pressure law, and constructs a roof structure model of the retreat area. The UDEC discrete element numerical simulation software was used to analyze the evolution characteristics of concentrated stress and the failure law of surrounding rock around the retracement channel under gradual excavation conditions. Based on the relationship between the position of the main roof fracture and the stability of the surrounding rock of the retracement channel, the instability mechanism of the surrounding rock of the retracement channel was revealed. A mechanical model of the surrounding rock of the retracement channel under the condition of a gradient coal pillar was established, and the energy criterion K for the instability of the surrounding rock was obtained. The method of adding anchor cables to strengthen the support of the surrounding rock of the retracement channel was proposed. The results indicate that the accumulation of energy in the surrounding rock of the retracement channel is greater than the internal consumption of energy, which is the direct reason for the instability of the surrounding rock of the retracement channel. The time to strengthen the support of the roof is when the working face is 15 m away from the retracement channel. According to the analysis of on-site monitoring results, the roof convergence and the two-sides convergence before and after strengthening the support were reduced by 90 mm and 140 mm, respectively. Under the strengthening of support, the slope of the retracement channel in the 360808 working face is slight, without roof fall, and the surrounding rock of the channel is effectively controlled, which is of great significance for ensuring the safe application of the retracement channel. It has reference value for the safety production of surrounding mines and is conducive to promoting the sustainable development of local resource-based society and economy.

Detection of hypersonic weak targets by high pulse repetition frequency radar based on multi‐hypothesis fuzzy‐matching radon transform

AbstractFor the integration detection of near space hypersonic weak targets by high pulse repetition frequency (PRF) radar, a novel method named Multi‐Hypothesis Fuzzy‐Matching Radon transform (MHFM‐RT) is proposed for the near space hypersonic target detection and tracking. For remote hypersonic target detection, to avoid range ambiguity, current radars always use a low PRF mode, which limit the number of pulse accumulations. Using the high PRF mode, the fuzzy folding will appear in the target range measurements when target trajectory crosses range fuzzy intervals. Therefore, there is a contradiction between range ambiguity and energy accumulation. The proposed method is used to match the fuzzy measurements, so as to realise the correct integration in the condition of range ambiguity. Firstly, considering the need of range ambiguity resolution, the mode of staggered PRF is used. Secondly, the first frame measurements are periodically extended for multiple‐fuzzy hypothesis. Finally, the weak target track is accumulated in MHFM‐RT domain, and the signal integration and ambiguity resolution can be realised simultaneously. The proposed method expands the Variable‐Diameter‐Arc‐Helix Radon transform (VDAH‐RT) method to fuzzy folding conditions. Compared with the existing methods, for 7‐scan measurements non‐coherent integration, the detection sensitivity of the proposed method is about 0.5–1 dB higher than that of the IMM hybrid filter algorithm, and about 1 dB higher than that of the RHT‐TBD approach, and it needs less storage space and has higher detection probability.

The Modeling of Disc-shaped Acoustic Black Hole Plate and Vibration Characteristics

The Acoustic Black Hole (ABH) structure has great potential in vibration and noise control due to the characteristics of high damping and energy accumulation. A dish-shaped two-dimensional acoustic black hole plate is proposed in order to reduce the possibility of the structural damage happened in conventional embedded ABH in the centre of the plate. The dish-shaped acoustic black hole plate only cuts ABH on the edge. The finite element method is often used to establish the model of acoustic black hole plates. However, it is high cost and low efficiency in computation. A semi-analytical theoretical model of the disc-shaped acoustic black hole plate based on Gaussian expansion method is established in order to improve computation efficiency. Meanwhile, the shape function filtering method is proposed to solve the problem of non-convergence when Gaussian expansion method is used to model a non-rectangular plate. A finite element model of the disc-shaped acoustic black hole plate is established and used to verify the accuracy of the proposed semi-analytical theoretical model. The results show that the dish-shaped acoustic black hole plate has excellent energy accumulation effect and can be used further as Dynamic Vibration Absorber (DVA) to reduce the vibration of host structure.

Emergence and growth of faults during earthquakes: Insights from a dynamic elasto-plastic continuum model

I use a dynamic two-dimensional plane strain model of an elasto-plastic (Mohr-Coulomb) material with velocity-weakening friction to numerically simulate the emergence and propagation of shear fractures that accumulate slip intermittently during earthquakes. The model considers a 10 × 10 km block of homogeneous crust with a small weak inclusion, subjected to slow simple shear. Results show that deformation is distinctly bimodal, consisting of long periods (lasting ca. 50–200 years) where deformation is dominantly elastic separated by rapid sliding events lasting a few seconds during which time deformation is strongly localised on narrow plastic shear bands (faults). In terms of energy expenditure, the interseismic period is overwhelming dominated by accumulation of elastic strain energy whereas during earthquakes, most of the drop in elastic strain energy is consumed (dissipated) by plastic work. Model earthquakes have maximum slip rates of a few meters per second, involve a few meters of slip and result in drop of mean differential stress of several megapascals. Most earthquakes are complex events involving near-simultaneous rupture of multiple fault segments that propagate at supershear velocities (close to the P-wave speed) while they also induce a significant amount of more diffuse off-fault inelastic deformation. Earthquakes may involve formation of new faults and/or reshear on previously formed faults, which are favourably reactivated owing to their low pressure. Most individual faults establish much of their length early, whereas during subsequent events they continue to accumulate displacement at virtually constant length. As the confining pressure is increased, ruptures are more dynamic, which leads to increasingly widespread inelastic deformation. Overall, the models highlight the complex temporal and spatial interactions that exist between different faults within an array that communicate especially during earthquakes through static and dynamic changes in the stress field.

Bi-functionality of Coral reef-like nano-range composites fabricated as g-C3N4/ppy/PSS for efficacious electrochemical super-capacitive energy accumulation and dye depletion

This study presents a series of Coral reef-shaped composites' recipe prepared after synthesizing g-C3N4 (G), in-situ polymerized pyrrole as polypyrrole (P) and Poly (styrene sulfonate or PSS or simply S taken in varied amounts), collectively denoted as GPS, that were further explored towards super-capacitive energy accumulation behaviour and a dye's photocatalytic gradation. After getting relevant and justifying advance characterization of the synthesized composites, super-capacitive applications of the composites were studied using the three techniques based on electrochemistry. Galvanostatic Charge Discharge validated the results as this composite (0.3 GPS) exhibited a noticeable energy density of 82.86 Wh/kg along with high power density as 224.3 W/kg at 1 A/g and specific capacitance as 1223.53 F/g at 10 mV/s using cyclic voltammetry. Excellent cyclic retention of 92.31% was observed for 0.3 GPS product over 6000 cycles. A pair of gadgets also lit for two minutes when charged for three minutes at 1.1 V using asymmetric device fabricated of 0.3 GPS.Photocatalytic activity of these composites was studied against Rose Bengal dye, with an appreciable degradation efficiency of 0.3 GPS as 89.85% and also with the efficiency 74.23% after six degradation rounds. Thus, the composite evidences about its dual properties with both the functionalities working successfully.

Development of a Testing System for High-efficiency Power Recovery Bag Accumulators

Currently, most of the bladder-type accumulator test benches used have problems such as large installed capacity, severe energy loss, and incomplete testing functions. This article focuses on the research of the testing requirements and power recovery issues of bladder-type accumulators. A new type of hydraulic schematic and electrical control system for power recovery bladder type accumulator testing based on mechanical compensation with dual output shaft motor transmission, differential charging and discharging of dual accumulators, and parallel addition of oil replenishing accumulators has been designed. A measurement and control software based on the LabVIEW platform has been developed. The experimental results show that the system’s power recovery efficiency can reach 60.5% by adopting a scheme of mechanical compensation type power recovery, differential charging and discharging of energy accumulator group, and parallel addition of oil replenishing energy accumulator. The testing system can accurately, efficiently, and conveniently complete various performance tests of hydraulic bladder accumulators.

Effects of mine tailing exposure on the development of early life stages of the marine copepod Calanus finmarchicus

ABSTRACT The demand for mineral resources is increasing mining activities worldwide. In Norway, marine tailing disposal (MTD) is practiced, introducing mineral particles into fjord ecosystems. We investigated the effects of two concentrations (high and low) of fine tailings from a CaCO3 processing plant on early life stages of the marine copepod Calanus finmarchicus. Results show that the exposure did not significantly impact hatching success or development in non- and early feeding life stages. However, feeding stage nauplii ingested tailings, which caused a significantly slower development in later nauplii stages in high exposure groups, with most individuals being two stages behind the control group. Further, high mortality occurred in late nauplii and early copepodite stages in low exposure groups, which could be caused by insufficient energy accumulation and depleted energy reserves during development. Individuals exposed to high exposure concentrations seemed to survive by arresting development and potentially by reduced activity, thereby conserving energy reserves. In nature, slower development could affect lipid storage buildup and reproduction.

Piano Concert by Y.N. Hummel No. 2 in a Minor Op. 85 in the Context of Biedermeier's Art of "Light" Pianism of the First Half of the 19th Century

The purpose of this study is the analysis of Y.H. Hummel's Second Piano Concerto from the perspective of Biedermeier's positions of "light" ("diamond") pianism of the Restoration era, which deployed saving the spiritual foundations of Rococo in the conditions of secularised art of the post-Vienna school. The methodological basis of the research is the intonation approach of the school of B. Asafyev in Ukraine, which is embodied in the works of D. Androsova, O. Markova, O. Muravska, L. Shevchenko and has direct implications for the institutions of Chinese musicology (see the works of Ma Wei, Wu Golin, others). The specifics of the methods of historical-descriptive, musicological analytical, cultural, stylistic comparative, interdisciplinary approach make up the specifics of the research apparatus of the author of the essay. The scientific novelty of the work is revealed in the fact that, for the first time in Ukrainian and Chinese musicology, the so-called Concerto of Y.H. Hummel is analysed in the light of the positions of Biedermeier's "diamond" pianism of "light play" in the continuation of Mozartianism in piano works (based on the works of D. Androsova and L. Shevchenko) and in the development of the concept of neo-symbolism of post-avant-garde modernity according to O. Markova in relation to the performing revival of Hummel's heritage. Conclusions. Piano concert by Y.N. Hummel's A-moll op. 85 is marked by the advantages of pianistic lyrical flourishes over the manifestations of theatrical drama. The predominance of the lyricism of piano flourishes feeds the positions of romanticism against the background of Biedermeier's ideal expressive instructions, inspired by religious sobriety and, like Rococo art, addressed to the ideal aspirations of the soul and a harmonious worldview. In the Concerto, we rely on Mozartian tectonics (the theme of the soloist in the second exposition, mainly a compensatory function of the orchestra), the structure is dominated by exposition, which "washes away" the sonata relations. The predominant position of "piano lyricism" of ultra-fast finger "small technique", the presence of genres (signs of march, nocturne, anthem) in the expressiveness of themes, "obliteration" of tempo-textural contrasts between the extreme and middle parts of the cycle are evident. The features of crescendoing drama with increasing movement intensity from the beginning to the end of the concert cycle in a two-phase (Parts I-II-III) presentation of energy accumulation are revealed, which corresponds to the two-phase nature of the early Christian liturgy honoured by the Biedermeier culture.
 Keywords: piano Mozartianism, pianism, "easy", "diamond" playing style, musical genre, style in music, concert.

Modeling and optimization of scintillating crystal layers for designing a three-layer phoswich Alpha-Beta-Gamma detector

Monitoring the level of radioactive contamination and the type of radiation in the environment is very important for the protection of facilities, employees, and people. Phoswich detector is one of the useful tools to identify different radiations and separate them from each other using different scintillating crystals. However, their design can be very diverse based on the type of particles analyzed and various parameters of scintillating crystals and needs optimization to have maximum efficiency. This work aims to optimize the scintillating crystal layers for the design of the three-layer alpha-beta-gamma phoswich detector based on Monte Carlo radiation transport calculations. The selection of the appropriate model for the type and thickness of each layer is based on the optimization of parameters such as energy accumulation, produced scintillation optical photons, attenuation of optical photons, and scintillation decay time. The results showed that the three scintillating layers of ZnS(Ag), CaF2(Eu), and LYSO(Ce) with optimal thicknesses of 25.01 μm, 3.50 mm, and 2.54 cm, respectively, have more suitable optical outputs for detecting common alpha-beta-gamma radionuclide emitters.

Influence of synthetic and natural microfibers on the growth, substance exchange, energy accumulation, and oxidative stress of field-collected microalgae compared with microplastic fragment

Synthetic microfibers (MFs), which are Microplastics (MPs), have not received attention commensurate with their abundance in the environment. Currently, limited studies on MFs have focused on their effects on marine organisms. It is therefore necessary to conduct exposure experiments of MFs on freshwater organisms to provide reference data for the ecological risk assessment of MFs. As a primary producer in freshwater ecosystems, microalgae have an ecological niche that is highly overlapping with that of MFs. In this study, we examined the effects of MFs on the growth of Chlorella and indicators of oxidative stress to examine their potential risk on the microalgae population. The results showed that inhibition rate of microalgae increased with MF concentration in the range of 0.01–100 mg/L. Compared with natural fibers such as cotton and wool, PET and PP fibers showed significant growth inhibition, but less so when in fragment form with the same material and concentration. PP and PET particles, whether fibers or fragments, increased the total antioxidant capacity of microalgal cells and caused oxidative damage. To determine the influence of MFs on the interaction of cells in the environment, the exchanged substances and accumulated energy of microalgae cells were also detected. The results indicated that PP and PET fibers, as well as fragments, increased the diameter and membrane permeability of microalgae cell, thus interfering with the cell division and substance exchange processes. PET fibers and fragments showed different interactions at the level of individual cells and populations. This suggests that the evaluation of MPs should consider examinations from cells to population and even community levels in the future.

Investigation of the compression-shear fracture characteristics of flaw-filled sandstone under confining pressure

In the field of rock engineering, the coupled effects of confining pressure and crack filling material on rock mechanical properties have not received widespread attention. In this study, the central cracked Brazilian disk specimen was used to investigate the fracture properties of sandstone in compression-shear loading mode in a confining pressure and crack-filling environments. Variations in peak load and fracture toughness were quantitatively evaluated for different confining pressures and fillings, accompanied by the establishment of quantitative relationships related to fracture toughness. The trend of linear increase in effective fracture toughness versus confining pressure arises primarily from the contribution of confining pressure. The filling material weakens the fracture toughness of the rock to a certain extent, which is attributed to the accumulation of energy during the failure of the sandstone and the reduction of the stress concentration at the crack tip. The crack propagation trajectory mainly exhibits the characteristics of a stretched wing crack, but shows a transition trend towards a shear crack to a certain extent.

Current-voltage characteristics of single-stage semiconductor magnetic pulse generators with a distinctive structure of the conversion link in the input circuit

Introduction. The main feature of the semiconductor magnetic pulse generators (SMPGs) is a slow accumulation of energy in the primary capacitor and its rapid introduction into the load by using a series of sequentially connected magnetic compression stages. Initially, these devices were mainly used for pumping gas lasers, but over the last decade SMPGs have been increasingly used in electric discharge technologies for water purification and air ionization to remove toxic impurities. At the same time, along with the practice of using these devices, development has also been achieved in the principles of their design and methods of mathematical modeling. Problem. The main drawback of the existing theory of SMPG’s stationary oscillations mode is an adoption of the saturable reactor (SR) model in approximation of the static magnetization curve of its core, as well as unidirectional nature of the energy transfer from the generator to the load. In most publication the exchange processes between the power source and SR are still not covered. Goal. Study of electrical and energy characteristics of low-voltage single-stage SMPG devices with series and parallel conversion stages in the charging circuit. Methodology. To achieve the set goal, this work uses comprehensive approach relayed on technical tools of setting up the experiment, numerical methods for processing measurement results, as well as an analytical method for describing electromagnetic processes in single-stage SMPG circuits. Results. The closed current-voltage characteristics of the SR are obtained, according to which the numerical calculations of the integral magnetic and energy characteristics of the proposed models are carried out. The features of the longitudinal capacitance charging process in a SMPG’s circuit with a parallel conversion stage, which occurs simultaneously in two adjacent circuits, are explained. Analytical expressions to describe the dynamics of magnetic flux density in the SR’s core as a time-depended function are derived. Based on the obtained hysteresis curve of the core, the exchange processes of energy transfer between the power source and the SR are explained. Practical value. The results of the research can be applied in the development of low-voltage SMPG circuits with improved energy-dynamic parameters.

Investigation into the Multistage Mechanical Damage Behavior of Columnar Jointed Basalts with Different Meso-Constitutive Relations and Model Sizes

Abstract The mechanical characteristics of columnar jointed basalts (CJBs) are generally considered to be subject to size effects. They display complex mechanical behaviors under lateral pressure, which may be related to the variation in the rock's mesoproperties. In this study, many nonuniform CJB models with various rock meso-constitutive relations and model sizes were established, and their influences on the strength and deformation properties, multistage mechanical damage behavior, and acoustic emission characteristics of CJBs were investigated. The results show that, as the residual strength coefficient increases, the compressive strength of CJBs rises, and the equivalent deformation modulus of CJBs decreases or increases slightly; with an increase in the model size, the compressive strength slightly decreases at first and then varies moderately, and the equivalent deformation modulus shows a fluctuating trend. Furthermore, the macro stress–strain relationships can be divided into different stages according to the corresponding damage behaviors. The strains and energy accumulations before peak stress was reached were further analyzed. The results greatly improve our understanding of the collapse process of CJBs and the instability precursors of related structures.

Feasibility Study for the Implementation of Photovoltaic Panels in Public Transportation in Barranquilla

The conservation of the environment and the use of clean energy is one of the main concerns of international governments. In this sense, encouraging the use of clean energy, both locally, nationally, and internationally, contributes to the development of countries. In this order of ideas, this work was motivated with the purpose of contributing to the scope of the SDGs at the national level, specifically, in the city of Barranquilla (Colombia). The thermal sensation inside the public transport in Barranquilla limits the quality of the service and, consequently, the satisfaction of the users due to the high temperatures (T > 30 °C). To address this problem, it is necessary to implement air conditioning systems that improve comfort conditions and are friendly to the environment. In this study, the feasibility of implementing photovoltaic panels as an alternative energy source for air conditioning units in public transport was examined. The study began with the dimensioning of the photovoltaic system and the accumulation of energy. A stress analysis was then performed on the chassis and bodywork of a selected bus. Finally, the work was evaluated based on the results obtained from the dimensioning of the mentioned systems. The results confirmed that a photovoltaic generator with a power of 35.88 kW and an energy storage capacity of 481,204 Ah is required. Additionally, the results also confirmed that the chassis and bodywork are structurally sound. The economic analysis carried out confirmed a Net Present Value and an Internal Rate of Return of 22,936 USD and 11.05%, respectively. The energy alternative proposed for the transport sector, based on the application of photovoltaic energy, constitutes an advance to meet international objectives in relation to the use of clean energy.

Energy Accumulation Law of Different Forms of Coal–Rock Combinations

Coal–rock disasters are becoming more and more severe as the intensity of coal mining increases. Due to its destructive power and resulting extensive area damage, rock burst is among the most critical threats to coal mine safety. It results from the combined action of the coal and the rock when affected by the mining process. To this end, we used a combination of coal and rock to conduct our studies. Combining a uniaxial compression experiment with theoretical analysis, this work investigated how different lithologies and coal–rock height ratios affect the mechanical properties of this combination and the law governing energy accumulation. We determined the following: When the coal–rock height ratios are dissimilar, the peak strength and modulus of elasticity of the combination show a negative correlation with the coal thickness share, and the pre-peak energy accumulation and impact energy index of the combination is positively correlated with the coal thickness percentage. In combination with the same coal–rock height ratio, the peak strength, elastic modulus, pre-peak energy accumulation, and impact energy index all increase with increased rock strength and elastic modulus. The presence of a hard rock layer affects the accumulation of pre-peak energy. Based on the experimental analysis, a theoretical model was established, and the surrounding rock stress negatively correlates with the percentage of coal thickness; the energy stored in the surrounding rock is directly proportional to the coal in the zone. Therefore, we inferred that the stress distribution of the surrounding rock as coal thickness changes is abnormal; substantial energy accumulation can swiftly initiate dynamic disasters, such as rock bursts. This study has important reference significance for preventing and controlling rock bursts in areas where coal thickness changes.

Hydrogeochemical characterization and precursor anomalies of hot springs in the North Tianshan orogen

The North Tianshan orogen consists of a series of thrust faults and is the most seismic region in China. In this paper, the characteristics of hot springs in the North Tianshan orogen are analyzed. Hydrochemical analysis of 13 hot springs and four mud volcanoes reveals that the cations of most hot springs are mainly Na+, while the anions are mainly Cl−.Atmospheric precipitation is the main recharge source for the hot springs in the study area, with recharge heights ranging from −9 to 2344 m. Heat storage analysis and trace element results showed deep fluid characteristics, which is consistent with deep circulation processes and regional extrusion pressure background. In addition, continuous measurements of six hot springs were conducted once every three days. The results showed that Cl− and SO42− concentration anomalies occurred before several earthquakes of ML4.0 in the North Tianshan orogen. The hot springs SWQ, HTB, and WS, which have deeper circulation depths, show better responsiveness than X10, which has a shallow circulation depth. The deep circulation of hot springs increases fault sliding friction, which contributes to energy accumulation and strong seismogenesis, and participates in the seismogenesis process. Therefore, continuous monitoring of ion concentrations of deep-circulation hot springs can help identify effective precursor anomalies in the North Tianshan orogen.