Abnormal Heat Research Articles

ФОРМИРОВАНИЕ ПОЛОЖИТЕЛЬНЫХ АНОМАЛИЙ ТЕМПЕРАТУРЫ ПОВЕРХНОСТИ ЧЕРНОГО МОРЯ

Based on the satellite data at the points of a high-resolution regular grid for the period from 2008 to 2021, positive anomalies of the sea surface temperature (SST) in the northern Black Sea and off the southwestern coast of Crimea have been identified. It has been shown that there are vast areas with an exceeding of SST over the mean for the measurement period up to 4-5 and 5-6°C and a monthly total area (for example, in May 2018) about 200000 and 100000 km2, respectively, in the northern Black Sea. The analysis of available satellite data has led to the conclusion that warm SST anomalies occur mainly in May and October. The maximum (over the entire analyzed period) warm SST anomaly (exceeding 5°C) was reached in May 2012, when its area was 200000 km2. The spatial structure and some statistical characteristics of the identified SST anomalies have been described and analyzed. It has been shown that the typical frequency of vast SST anomalies is at least one case per several years, while they are generated by abnormal heat fluxes on the sea surface with the inflow of anomalously warm river water in shallow areas of the northwestern shelf and spread to the open sea areas due to the horizontal advection of predominantly wind-driven origin. The average annual SST anomalies off the northwestern coast of Crimea and in the northern Black Sea correlate at a level of 0.97.

How Are the Abnormally Hot Chromosphere and Corona Heated by the Solar Magnetic Fields?

The corona is a structure possessed by stars, including the Sun. The abnormal heating of the solar corona and chromosphere is one of the greatest mysteries in modern astronomy. While state-of-the-art observations have identified some candidates of magnetic activity events that could be responsible for this abnormal heating, and theoretical studies have proposed various heating modes, a complete physical picture of how they are heated as a whole remains elusive. In this study, the characteristics of the heated corona and chromosphere are investigated, and for the first time, the question of how they are abnormally heated is explicitly answered by analyzing the long-term observations of the global chromosphere in the Ca ii K line and the global corona in the coronal green line. The findings reveal that both the quiet chromosphere and corona are in antiphase with the solar cycle, whereas the active chromosphere and corona are in phase with it. Different parts of the solar corona and chromosphere exhibit significantly different variation characteristics and are found to be heated by different magnetic categories and probably in different modes. This study posits that unraveling the heating mystery is best approached through the lens of magnetic categories, rather than magnetic activity events.

Study on the Mechanism Effect of Bending Loads on the Decay-like Degradation of Composite Insulator GFRP Core Rod

This paper investigates the deterioration of, and the abnormal temperature rise in, the GFRP core rod material of compact V-string composite insulators subjected to prolonged alternating flexural loading under wind-induced stresses. The axial stress on the GFRP (Glass Fiber Reinforced Plastic) core rod, resulting from transverse wind loads, is a focal point of examination. By establishing a stress model and damage model, the paper simulates and computes the evolution of damage in the outer arc material of composite insulator core rods subjected to alternating flexural loads. Additionally, a multi-factor coupled aging platform is set up, integrating humidity, heat, and mechanical stress, to simulate the crazing deterioration process of composite insulators under alternating flexural loads. Experimental results reveal that during 400,000 alternating load cycles, the core rod underwent stages of surface damage, damage increasing, fatigue embrittlement, matrix hydrolysis, and fiber fracture. Simultaneously, the silicone rubber sheath on the outer side of the composite insulator’s bending arc develops cracks over aging time, creating pathways for moisture ingress into the interface and core rod. The dielectric constant and dielectric loss factor of the aging region of the core rod increase to varying degrees compared to the non-aging part. Moreover, the degree of abnormal heating of the samples intensifies with the duration of aging experiments. These findings underscore the significance of understanding the aging and decay-like fracture process of compact line V-string composite insulators. They provide crucial insights for future research aimed at enhancing the material properties of composite insulator core rods.

The significance of alhagi in climate moderation and prevention of pastures degradation

The formation of the Aral Sea has a negative effect on the climate conditions of the Central Asian region, and the climate of Uzbekistan is characterized by sharp continental, abnormal heat and cold air. The summer heat has a significant effect on the flora and green cover of the hot pastures (yaylak).

Thermal bleaching in the northern South China Sea: impact of abnormal environment and climate on high-latitude coral reefs.

Extensive coral bleaching events can result in catastrophic degradation of coral reefs and reorganization of coral communities. In the present study, we analyzed the spatial differences in coral bleaching and possible reasons of large-scale coral bleaching, based on the results of a survey carried out in the northern South China Sea in 2020. In addition, we have continuously monitored the sea surface temperature (SST) of the northernmost Weizhou Island for more than six years. The living coral cover at Weizhou Island (W), Xuwen Nature Reserve (X), and Haihua Island (H) was relatively high at 24.6% ± 4.8%, 12.1% ± 3.8%, and 8.1% ± 2.6%, respectively, whereas their bleaching rates were 9.7% ± 2.6%, 9.7% ± 3.3%, and 6.9% ± 2.1%, respectively. Among them, the living coral cover of W was significantly different from those of X and H, whereas the bleaching rate was not significantly different among the three areas. In all three areas, the massive and encrusting corals predominate and exhibit relatively high bleaching rates, with Porites lutea and Bernardpora stutchburyi being the dominant species. In addition, the temperature monitoring results of Weizhou Island for six consecutive years showed that the critical SST of coral bleaching was 31.5 ℃. The monitoring results also showed that the average SST of Weizhou Island was 32.1 ℃, exceeding 32 ℃ in July 2020 for up to 533h. The longest continuous time when the SST exceeded 32 ℃ was 97h. These findings indicated that the coral bleaching event that occurred in the Beibu Gulf during 2020 was a large-scale and high-temperature transient event that presented a relatively homogeneous threat to the coral communities. We inferred that this sudden heat stress event was caused by the enclosed tidal current in the Beibu Gulf, which prevented the southern upwelling from reaching the north, as well as by the inability of the SST to decrease without rainfall caused by typhoon cyclones. Our findings suggested that abnormal heat waves can result in coral bleaching at high latitudes and even coral reef degradation. Furthermore, our study provides a new perspective for investigating the self-recovery and reorganization of coral communities following accumulated coral bleaching.

Heat Flow Prediction in Songliao Basin Based on Deep Neural Network

The heat flow is the key data for accurately predicting the contribution of underground heat, but due to the high cost of measurement, the spatial difference is huge, and the heat flow information in some areas is little known. This paper uses deep neural network technology to perform machine learning on a large number of relevant geological and geophysical features and heat flow measurements on a global scale. In addition, the model uncertainty quantification process is introduced, and the reliability of the prediction results is discussed based on the global sensitivity analysis and correlation calculation of the deep learning method. Finally, for the distribution map of heat flow and absolute difference in the Songliao Basin in the study area, the measured data error is less than 11%, and the predicted absolute difference is less than ±20 mW/m2. The results prove the accuracy of the method and the abnormal high heat flow in the central region of the basin. The existence of, further combined with the results of geophysical surveys, provides evidence for the analysis of regional thermal causes.

Countermeasures of abnormal heating of cable grounding line near three-phase reactor

Countermeasures of abnormal heating of cable grounding line near three-phase reactor

Seasonal analysis of land surface temperature using local climate zones in peak forest basin topography: A case study of Guilin

Understanding the characteristics of Land Surface Temperature (LST) is crucial to mitigate the Surface Urban Heat Island (SUHI) effect. Local Climate Zones (LCZs) framework can be applied in LST analysis and SUHI quantification. However, this framework primarily focuses on evaluating detailed local-scale SUHI, thereby failing to provide a comprehensive assessment of the overarching SUHI trends at the urban level. Additionally, existing LST analyses ignored geographic factors, resulting in partial analysis of LST, especially in areas with complex geography. To fill these gaps, the study develops a SUHI assessment method combining an improved surface urban heat intensity ratio index with LCZs-based SUHII, enabling a dual evaluation of both overall and detailed SUHI effect. The impact of geographic factors, both topography and natural features, on seasonal LST patterns is investigated, especially within built LCZs. Additionally, the spatio-temporal image fusion model is employed to address issues of cloud effects or image mutilations in LST results. Guilin, with unique peak forest basin topography, is selected as a case study to represent complex geographical areas. The results reveal the following: (1) An abnormal heat island phenomenon occurs during winter due to Guilin's distinctive geomorphological conditions. (2) Cooling effects influenced by mountains and water bodies on different built LCZs exhibit seasonal variation, with the strongest cooling effect observed within a 50-m distance. LCZ 2 consistently exhibits the strongest cooling effect. The study offers valuable insights for guiding decisions in sustainable urban planning and design, especially in cities influenced by complex local geography.

Study on the convective heat transfer characteristics of supercritical CO2 in mini-channels under unilateral heating conditions for application in a compact solar receiver

The mini-channel in compact solar receiver deliver the high performance in both heat transfer (HT) and pressure resistance. However, the severe variation of thermophysical properties of supercritical CO2 (S-CO2) coupling with the complex nonuniform distribution of solar flux leads to the abnormal flow and heat transfer (FHT) performance of S-CO2 in mini-channels. The present work numerically investigated the detailed FHT of S-CO2 in the horizontal mini-channel with one-side heating. The impacts of buoyancy and flow acceleration on FHT of S-CO2 are demonstrated in detail. The results show that the buoyancy effects can lead to the enhancement on circumferentially average heat transfer performance of S-CO2 while the local deterioration at the top. In contrast, the thermal acceleration effects can worsen the S-CO2 HT. The buoyancy and thermal acceleration effects can be ignored when Ri ≤ 2.7 × 10−3 and Ac ≤ 7.8 × 10−8, respectively. The empirical formula for S-CO2 HT in the mini-channel under single-side heating conditions is developed, with a maximum error of 4.5%.

The role of buoyancy and thermal acceleration in heat transfer deterioration and thermal oscillation for the CO2 around pseudo-critical region

Trans-critical CO2 Rankine cycle has great potential in converting low-grade heat into electricity, because of its good temperature glide matching between working medium and heat source. However, the drastic variation in thermo-physical properties of CO2 around the pseudo-critical region causes the abnormal flow and heat transfer behaviors. In this paper, the heat transfer deterioration and thermal oscillation in the heat addition of trans-critical CO2 cycle are investigated by experiments. The test section is heated uniformly by a DC power (0∼6 kW) and the minimum Reynolds number in the test section inlet is about 8000 (it is much larger than 2300) for the all cases. A shear stress reconstruction model is corrected by introducing the velocity profile of turbulence in the boundary layer to attempt to provide a quantitative criterion for deterioration and oscillation. The role of buoyancy and thermal acceleration in heat transfer deterioration and thermal oscillation is elucidated by connecting the shearing-stress reconstruction model and experimental results. It is found that, the thermal acceleration in the near-wall zone provides the key motivation to drive the heat transfer deterioration. The thermal oscillation is driven by the transition between partial and full re-laminarization flows in the local zone of heat transfer deterioration. When (Δτa/τw)<1&(Δτ/τw)tot>1 or 0.1<(Δτ/τw)tot<1, the turbulence is partially re-laminarized. When(Δτa/τw)>1&(Δτa/τw)>>(Δτbo/τw), the intense thermal acceleration causes the turbulence to be fully re-laminarized in the near-wall zone and it maintains the new laminar boundary . The turbulence is partially re-laminarized in the lower boundary and it is almost full re-laminarization in the upper boundary of the oscillation wall temperatures. The results confirm that the emergence of heat transfer deterioration and oscillation instability in mixed turbulent convective relate with the change of flow states caused by acceleration and buoyancy effects.

Population Dynamics and Distribution of the Lake Smelt, a Dwarf Form of the European Smelt Osmerus eperlanus (Osmeridae), and the Black Sea Sprat Clupeonella cultriventris (Clupeidae) while Cohabiting the Rybinsk Reservoir

The data for a 23-year period (2000–2022) on the population dynamics and distribution of the lake smelt (a form of the European smelt Osmerus eperlanus) and the Black Sea sprat Clupeonella cultriventris in the Rybinsk Reservoir have been summarized. The lake smelt dominated the reservoir pelagial from the 1950s to the mid-1990s. An anomalously low water level in the reservoir in 1996 and abnormal (for this reservoir) water warming in subsequent years led to elimination of the species from the reservoir ichthyofauna in 2002. The Black-Sea sprat invaded the reservoir in the mid-1990s; its population irruption occurred in the early 2000s (during the depressed state of the smelt population). Currently, this species dominates in the pelagial of the reservoir. Since the early 2000s there were noted two periods when the lake smelt was found in practically all parts of the Rybinsk Reservoir and the sprat abundance was also high. However, high water temperatures in 2010 and 2021, as well as low level in 2014, resulted in almost complete disappearance of the lake smelt disappeared. During the periods of cohabitation of the studied species, a significant similarity in the diet of individuals of both species with the size of up to 80 mm has been noted. The larger smelt fed on larger plankton, and in the summer also on fish. Currently, the main limiting factor negatively affecting the recovery of the smelt population in the Rybinsk Reservoir is the abnormal heating of the water column in some years.

East Asian summer rainfall stimulated by subseasonal Indian monsoonal heating

The responses of the East Asian summer monsoon (EASM) to the Indian summer monsoon (ISM) have been the subject of extensive investigation. Nevertheless, it remains uncertain whether the ISM can serve as a predictor for the EASM. Here, on the basis of both observations and a large-ensemble climate model experiment, we show that the subseasonal variability of abnormal diabatic heating over India enhances precipitation over central East China, the Korean Peninsula, and southern Japan in June. ISM heating triggers Rossby wave propagation along the subtropical jet, promoting southerly winds over East Asia. The southerly winds helps steer anomalous mid-tropospheric warm advection and lower-tropospheric moisture advection toward East Asia, providing conditions preferential for rainband formation. Cluster analysis shows that, depending on jet structures, ISM heating can serve as a trigger as well as a reinforcer of the rainband.

Thermoluminescence behavior of Ce3+ doped lanthanum tri-borate phosphor for dosimetry applications

The combustion method was used to synthesize Ce3+ doped LaB3O6 phosphors in a range of dopant concentrations. Both the un-doped and Ce3+ doped LaB3O6 samples matched the required reference card, according to X-ray diffraction patterns. TL glow curves of Ce3+ doped LaB3O6 samples at various dopant concentrations were examined by employing various optical detection filter combinations to define TL characteristics. LaB3O6:Ce3+ (1%) and IRSL-TL 565 nm were selected as the suitable sample and appropriate detection filter pairing. The TL maximum with a higher intensity was seen during preheating trials (with 2 °Cs−1) at around 270 °C. The experimental results showed feasible linearity (R2 = 0.998 and b = 1.054) between 5 and 1000 Gy for the dose response of LaB3O6:Ce3+ (1%). The short-term fading test was conducted at various time intervals up to a week. The findings showed that the dosimetric peak strength was almost constant for up to 5 days. However, an additional spurious maximum appeared at the higher temperature zone. Each sample showed an abnormal heating rate effect, which can be explained by localized electrons caught in the intermediate excited state, which is capable of radiative transitions via the conduction band. To find the overlapping peak numbers and determine the kinetic parameters of preheated LaB3O6:Ce3+ (1%), various heating rates, TM-Ts, initial rise, and computerized glow curve deconvolution techniques were utilized. The results suggest that LaB3O6:Ce3+ may be an appropriate material for TL dosimetry applications due to its efficient TL characteristics.

Anomaly detection with a container-based stream processing framework for Industrial Internet of Things

Online anomaly detection is a key challenge for industrial internet of things (IIoT) applications, as anomalies may occur in data streams from sensors and cause losses or damages. However, most existing methods for online anomaly detection have limitations in efficiency, effectiveness and timeliness, especially with the massive and distributed data streams from IIoT devices. Therefore, developing a data stream processing framework to discover anomalies in time and ensure the proper operation of the system is an urgent issue for IIoT. In this paper, we propose a flexible stream processing framework that enables online anomaly detection for IIoT applications. The framework exploits a distributed computing architecture based on docker containers to improve flexibility, migration capability and customization. The framework also uses a central mediator to coordinate data stream processing tasks running on different docker nodes. Moreover, we develop a prediction-based online anomaly detection model that consists of batch model training and data stream anomaly detection processes. The model uses long short-term memory (LSTM) neural networks to predict data stream values and a dynamic sliding window method to model prediction errors and detect anomalies. We implement a case study to detect abnormal heating temperatures from an industrial heating plant and evaluate the performance of the proposed framework and anomaly detection model. The results show that our framework and model can achieve high accuracy and low latency in detecting anomalies, and they outperform existing methods in terms of scalability, efficiency and adaptability for IIoT applications.

The occurrence and distribution of phenylated aromatic hydrocarbons and terphenyls during heating experiments of marine and lacustrine source rocks in a semi-open system

This study aimed to explore the presence and distribution of phenyl substituted polycyclic aromatic hydrocarbons (Ph-PAHs) and polyphenyls in one Middle Devonian marine carbonate sample from the Western Canada Sedimentary Basin and one Cretaceous lacustrine shale sample from the Songliao Basin by artificially heating them in a semi-open system. GC-MS analysis of residual extracts and expelled oils showed no trace of phenylnaphthalenes, terphenyls, phenylphenanthrenes and binaphthyls in original extract and low temperature pyrolysates, but these compounds emerged at high temperatures, indicating a pyrogenic origin. Compared to the lacustrine shale, the marine carbonate consistently exhibited higher concentrations of these compounds that are likely controlled by the depositional environment. The main reaction mechanisms involve consecutive reactions of free radicals, with phenylation of unsubstituted aromatic hydrocarbons being the predominant reaction under high thermal stress. While oxidized organic matter may facilitate the formation of Ph-PAHs and polyphenyls, they can be formed from any type of organic matter. The presence of metal oxidants was found to be unnecessary, as high temperatures alone were sufficient to promote the formation of these compounds. Thus, their occurrence indicates abnormal heating regardless of the maturity of the host rocks. Phenylnaphthalenes were produced earlier than other Ph-PAHs and polyphenyls. While stable Ph-PAH and terphenyl isomers increase with simulation temperature, thermal maturity parameters derived from phenyl-PAHs and polyphenyl are insensitive to maturity except for p-TrP/m-TrP, which increases almost linearly with temperature in Brightholme shale. Ph-PAHs and polyphenyls were found to be less thermodynamically stable than conventional PAHs. Under extremely high thermal stress, they lose hydrogen atoms and transform into more stable condensed PAHs. The study provides valuable insights into the occurrence of high abundance phenyl-aromatic and polyphenyl compounds in sedimentary organic matter, enhancing our understanding of these complex organic molecules.

Study on temperature distribution and smoke diffusion characteristics of cable shafts in high-rise buildings

The smoke and poisonous gas produced during combustion is one of the direct hazards of cable fire. For power cables laid vertically in the cable shaft of high-rise buildings, the chimney effect will speed up the spread and expand the harm of cable fire. The paper proposes a simulation method based on fire dynamics theory to analyze the diffusion and spread characteristics of cable fire. First, a three-dimensional model of the double-floor cable shaft with multiple cables laid vertically inside was built in the paper. Second, with the abnormal heating caused by overload or insulation breakdown as the excitation condition, the development process of cable fire is simulated. The diffusion of smoke and gas during the whole combustion process is studied and discussed. Then, the paper compares the simulation results of the model with different fire blocking materials. The simulation results show that the application of blocking materials will cause differences between the spread of fire and flue gases, and the difference can be used to evaluate the quality and performance of the fire blocking material. Finally, A test platform is constructed to verify the validity of the simulation analysis.

The Abnormal Heating Phenomenon Of A 1000 KV Composite Insulator Based on Finite Element Simulation Calculations

The abnormal heating of composite insulators will accelerate the deterioration of insulation materials, which will lead to abnormal heating at the high-voltage end due to the increase of dielectric loss. In this study, a finite element multi-physical field simulation was adopted and combined with the actual field test results. Four kinds of electric-thermal coupling simulation models of the 1000 kV composite insulator were established, namely, new, aged, aged with defects, and aged with defects and accumulated contamination. The electric field simulation results showed that interface defects and surface fouling would seriously distort the electric field distribution of composite insulators. The maximum electric field increased from 3.73 kV/cm to 9.30 kV/cm. With the dielectric loss as the heat source to calculate the temperature rise, the maximum temperature rise of the aging contaminated composite insulator with defects was 17.86 K, which was similar to the field test results of the 1000 kV composite insulator. The research results provide a reference for analyzing the cause of abnormal heating failure in composite insulators.

Abnormal heat capacity of phonons in solid 4He

In the solid 4He at zero temperature, there are the acoustic waves, which manifest themselves in the form of phonon pairs. We show that the phonon system in solid 4He can undergo the Bardeen–Cooper–Schrieffer (BCS) condensation. In the BCS condensation state, the phonon system possesses a new kind of quasiparticle, the dressed phonon, whose velocity is a monotonically increasing function of temperature. The phonon system undergoes a first-order phase transition from the normal state to the BCS condensation state. We derive the low-temperature expression of the phonon heat capacity in the BCS condensation state, which considerably deviates from the Debye [Formula: see text] law in classic solids.

A Comparative Study of Abnormal Heating Composite Insulators.

The abnormal heating of composite insulators on transmission lines frequently occurs, seriously threatening the power grid's safe and stable operation. For different types of abnormal heating composite insulators, undifferentiated replacement wastes a lot of labor and material resources. This study explores the abnormal heating composite insulators under different environmental humidity and wind speed conditions. The heating and discharge of composite insulators are observed, and the heating range, heating shape, and temperature rise (ΔT) are analyzed. The abnormal heating of the sheath-aging composite insulator is related to the aging of the silicone rubber and the environmental humidity. The partial discharge caused by the core rod's defect is the primary source of the temperature rise in the decay-like insulator. The heating range of the contaminated insulator is connected to the environmental humidity, and the ΔT increases with the salt density. The ΔT and heating range of the three types of abnormal heating increase with the ambient humidity. The heating phenomenon under low humidity is an important characteristic that distinguishes decay-like and contaminated insulators from sheath-aging insulators. Therefore, the on-site infrared inspection should be carried out in sunny and windless weather to prevent the impact of high humidity and wind speed on infrared temperature measurement.

Effect of memory behavior on electric-field-induced phase transition and electrocaloric response in antiferroelectric ceramics

Field-induced phase transition in antiferroelectric (AFE) materials always facilitates giant positive/negative electrocaloric (EC) responses for a promising cooling application, while it is not only associated with external field conditions but also applied field history, i.e., memory behavior. Herein, we demonstrate that memory behavior increases the likelihood of observing an EC response when the operating field is parallel to the pre-poling field, as compared to the antiparallel condition. Additionally, when the temperature is slightly above the AFE-ferroelectric (FE) phase transition temperature, the field-off process induces a two-step microstructure change, characterized by a rapid domain rotation followed by a slow phase transition, which finally produces an abnormal EC heat flow signal. Through a Landau theory analysis, this kinetic behavior is contributed to the competition between the ferroelectric (FE) order pinned by memory behavior and the thermal agitation favored AFE state. This work deepens the understanding of the phase transition in the ferroelectric system.