High Temperature Damage Research Articles

Laboratory and Field Performance Evaluation of High-Workability Ultra-Thin Asphalt Overlays.

The defects of poor workability and inadequate pavement performance of the ultra-thin asphalt overlay limited its application in the preventive maintenance of pavements. In this study, a high-workability ultra-thin (HWU) asphalt overlay scheme was proposed. A high-strength-modified asphalt binder and an optimized HWU-10 gradation were used to prepare the HWU asphalt mixture and explore its laboratory performance. Furthermore, the HWU asphalt mixture was used for the test road paving. Based on the field performance test results before and after the test road for one year of traffic operation, the application performance of the HWU asphalt mixture and styrene-butadiene-styrene (SBS)-modified asphalt mixture was compared and analyzed. The results showed that the HWU asphalt mixture possessed satisfactory laboratory pavement performance, and its high-temperature stability and moisture damage resistance were better than those of the SBS-modified asphalt mixture. The asphalt mixture prepared using HWU-10 gradation was easily compacted and showed good workability. After one year of operation, all field performance of the ultra-thin overlay paved with HWU asphalt mixture met the specification requirements, but its flatness and skid resistance decreased. It is worth mentioning that the HWU asphalt mixture was significantly better than the SBS-modified asphalt mixture in terms of performance degradation resistance and rutting resistance. The studies to enhance the road intersection pavement performance and ensure the homogeneous dispersion of polyester fibers in the asphalt mixture will be considered in the future.

Research progress about photothermal nanomaterials with targeted antibacterial properties and their applications in wound healing

With the development of photothermal nanomaterials, photothermal therapy based on near-infrared light excitation shows great potential for the bacterial infected wound treatment. At the same time, in order to improve the photothermal antibacterial effect of wound infection and reduce the damage of high temperature and heat to healthy tissue, the targeted bacteria strategy has been gradually applied in wound photothermal therapy. In this paper, several commonly used photothermal nanomaterials as well as their targeted bacterial strategies were introduced, and then their applications in photothermal antibacterial therapy, especially in bacterial infected wounds were described. Besides, the challenges of targeted photothermal antibacterial therapy in the wound healing application were analyzed, and the development of photothermal materials with targeted antibacterial property has prospected in order to provide a new idea for wound photothermal therapy.

Female fruit flies cannot protect stored sperm from high temperature damage

Recently, it has been demonstrated that heat-induced male sterility is likely to shape population persistence as climate change progresses. However, an under-explored possibility is that females may be able to successfully store and preserve sperm at temperatures that sterilise males, which could ameliorate the impact of male infertility on populations. Here, we test whether females from two fruit fly species can protect stored sperm from a high temperature stress. We find that sperm carried by female Drosophila virilis are almost completely sterilised by high temperatures, whereas sperm carried by female Zaprionus indianus show only slightly reduced fertility. Heat-shocked D. virilis females can recover fertility when allowed to remate, suggesting that the delivered heat-shock is damaging stored sperm and not directly damaging females in this species. The temperatures required to reduce fertility of mated females are substantially lower than the temperatures required to damage mature sperm in males, suggesting that females are worse than males at protecting mature sperm. This suggests that female sperm storage is unlikely to ameliorate the impacts of high temperature fertility losses in males, and instead exacerbates fertility costs of high temperatures, representing an important determinant of population persistence during climate change.

Multi-material additive-manufacturing of tungsten - copper alloy bimetallic structure with a stainless-steel interlayer and associated bonding mechanisms

Copper alloy–tungsten (CuA-W) material combination offers high-temperature damage resistance and excellent plasma radiation resistance. At present, there is a lack of knowledge on laser-based powder bed fusion (LPBF) additive manufacturing of CuA-W bimetallic structures. Here we show the influence of the build strategies (including directly bonding, using CuA-W powder mixture, and using the stainless steel (SS) interlayer) on the bonding of CuA to W. The experimental results show that pure CuA became spherical on the surface of solid W. The powder layers composed of the CuA-W mixture are thermally deformed after printing several layers. Using a SS transition layer between CuA and W, good bonding between the materials is achieved due to solid-state diffusion and grain boundary diffusion. We have also found that if the melting points of the two materials are significantly different, the printing of the high melting point material first will most likely make the material interface unmelted in multi-material LPBF. The material combination must have good wettability and a high element solid-state diffusion coefficient to achieve good bonding in such a condition. This study would be helpful for future investigation on multi-material AM involving a metallic material combination with significant difference in their melting points.

Metabolomic profiling of brassinolide and abscisic acid in response to high-temperature stress.

Hormone treatment enhanced the content of osmotic substances under high-temperature conditions. The effect of ABA and BR treated separately is better than treated together. To determine the effect of abscisic acid (ABA), brassinolide (BR) and ABA + BR on grape quality under high-temperature stress, various metabolites were analyzed. Compared with the control (CK), DL-tryptophan, D-raffinose, geniposidic acid, dodecanedioic acid and polyphenols were found to be higher after ABA treatment. After BR treatment, amino acids and poricoic acid B were higher than in CK. And carbohydrates and amino acids were up-regulated after ABA + BR treatment. BR and ABA + BR treatment also induced higher endogenous ABA and epibrassinolide contents. In addition, treated grape had higher soluble solid concentrations and soluble sugar content, and delayed the degradation of middle lamella and microfibrils. Antioxidant and heat shock-related genes were examined, which significantly increased in treated grape. The finding of this study suggested that ABA, BR and ABA + BR are very useful for alleviating high-temperature damage by increasing the accumulation of osmotic adjustment substances, and endogenous hormones content.

Electromagnetic self-encapsulation of carbon fiber reinforced Al matrix composite phase change material for high-temperature thermal energy storage

Realizing the effective encapsulation of eutectic Al-Si melt is of paramount significance for developing the Al matrix phase change materials in the high-temperature heat storage field. In this paper, a carbon fiber reinforced Al matrix composite phase change material with a Si-rich◎Si-poor cladding structure ([Cf×Si-rich]◎EAl-Si cPCM) was prepared by controlling the precipitation behavior of primary Si under electromagnetic stirring, which can realize the self-encapsulation of eutectic Al-Si alloy. The thermal and structural properties in steady state and non-steady state of the [Cf×Si-rich]◎EAl-Si cPCMs were systematically investigated. The results show that the [Cf×Si-rich] shell has a high thermal conductivity of 53.3–100.7 W/m·K at 200 °C~500 °C. With the increase of Si content in initial Al-Si melt, the high-temperature damage tolerance of the [Cf×Si-rich]◎EAl-Si40 cPCM prepared by Al-40Si is 62.8% higher than that of the [Cf×Si-rich]◎EAl-Si25 cPCM prepared by Al-25Si, but the heat storage capacity is decreased by 22.7%. The [Cf×Si-rich]◎EAl-Si30 cPCM prepared by Al-30Si melt is considered to have the best comprehensive property. Under the non-steady working condition, the [Cf×Si-rich]◎EAl-Si30 cPCM exhibited excellent structural stability and great phase change characteristics (0.3% fluctuation of the melting latent heat and 1.4% fluctuation of the phase change temperature). This work offers new self-encapsulation strategy for extending the application process of Al matrix PCM to the field of high-temperature thermal energy storage.

Expression and role of cystatin C in hyperthermia-induced brain injury in rats.

Cystatin C, the full name of cystatin C, is one of the most potent cathepsin inhibitors currently known, which can strongly inhibit cathepsin in lysosomes and regulate the level of intracellular proteolysis. Cystatin C plays a very broad role in the body. High temperature-induced brain injury leads to very serious damage to brain tissue, such as cell inactivation, brain tissue edema, etc. At this time, cystatin C can play a crucial role. Based on the research on the expression and role of cystatin C in high temperature-induced brain injury in rats, this paper draws the following conclusions: high temperature can cause very serious damage to the brain tissue of rats, which can seriously lead to death. Cystatin C has a protective effect on brain cells and cerebral nerves. When the brain is damaged by high temperature, cystatin C can relieve the damage of high temperature to the brain and protect brain tissue. In this paper, a detection method for cystatin C with more outstanding performance is proposed, and compared with the traditional detection method, the detection method in this paper is verified to have more accurate accuracy and excellent stability through comparative experiments. Compared with traditional detection methods, it is more worthwhile to use and is a better detection method.

A Hybrid Local/Nonlocal Continuum Mechanics Modeling of Damage and Fracture in Concrete Structure at High Temperatures

This paper proposes a hybrid peridynamic and classical continuum mechanical model for the high-temperature damage and fracture analysis of concrete structures. In this model, we introduce the thermal expansion into peridynamics and then couple it with the thermoelasticity based on the Morphing method. In addition, a thermomechanical constitutive model of peridynamic bond is presented inspired by the classic Mazars model for the quasi-brittle damage evolution of concrete structures under high-temperature conditions. The validity and effectiveness of the proposed model are verified through two-dimensional numerical examples, in which the influence of temperature on the damage behavior of concrete structures is investigated. Furthermore, the thermal effects on the fracture path of concrete structures are analyzed by numerical results.

Study on the effects of temperature and immersion on the acoustic emission and electromagnetic radiation signals of coal rock damage under load

As the mining depth increases year by year, the geological environment of the coal seam becomes more complex. Coal rocks are vulnerable to damage from high temperature, immersion, high ground stress and other factors. This study is aimed at realizing the monitoring and early warning of coal rock dynamic disasters in complex environments such as high temperature and immersion. Firstly, mechanical properties of coal rocks after high temperature and immersion treatment were tested through experiments. It was found that both high temperature and immersion can cause mechanical damage to coal rock. In addition, the acoustic emission (AE) and electromagnetic radiation (EMR) signals generated by coal rock samples during failure were collected in real time. The following conclusions were drawn: All these signals are closely related to the damage degree of coal rock. The AE and EMR signals generated by coal rock under load after different temperature treatments were different, and their intensity decrease after immersion treatment. Furthermore, the damage of coal samples caused by high temperature and immersion was explored through quantitative analysis, and the evolution law of crack propagation during coal rock failure was discussed. The mechanical properties of coal rock after the damage of high temperature and immersion and the mechanisms of AE and EMR signal generation and variation during deformation and failure were revealed. This study provides theoretical guidance for the monitoring of coal rock dynamic disasters.

A new Cr25Ni35Nb alloy critical failure time prediction method based on coercive force magnetic signature

High-temperature damage in Cr25Ni35Nb alloys can be differentiated into four stages: the almost perfect stage, Carbide grain boundary coarsening stage, early creep stage and critical failure stage. In this paper, a novel approach based on a magnetic signature to monitor the alloy transitions between the four stages is proposed. Since the difference (ΔNi/Cr) between the content ratio of Ni to Cr in grains and the average value of the ratio of Ni to Cr of the alloy vary at different stages, these variations are highly correlated to the magnetic signature, coercive force (Hc). Thus, the curve of Hc vs ΔNi/Cr, which is “M” shaped over the whole life of the alloy, can be used to estimate the remaining life of the alloy tube using the easy measurement of coercive force. The first “U” inflection point indicates that the early creep stage has started and the second inverted “U” inflection point indicates that the critical failure stage is coming up. By identifying the inflection points, the alloy critical failure time can be predicted.

Bayesian logistic regression: An application for carbonisation damage in four wood species

ABSTRACT This paper aimed to measure the carbonization action in four wood species with different densities formed by a variety with global utilization, eucalyptus grandis, and other three native species from Brazil, cupiuba, guapuruvu and morototoni. The analysis included the verification of damages from carbonization at high temperature as well as the influence of these covariates by the Bayesian Logistic Regression. The analysis verified the convergences from R-Hat diagnostic and Markov chains. Statistical model of temperature-species covariates was selected, since it presents the possibility of a more plausible explanation for the assessed data set. Eucalyptus grandis and guapuruvu wood species showed the greatest damage volumes caused by carbonization. Density was not a covariate that interfered, statistically, in this analysis of high temperature damages. Regarding wood species, the eucalyptus grandis differed significantly from the Bayesian model, both from cupiuba and morototoni woods. The detailed analysis evinced the efficient performance of the Bayesian model, which is an alternative option for studies about the carbonization of forest resources.

Hydrogen effect on flame extinction of hydrogen-enriched methane/air premixed flames: An assessment from the combustion safety point of view

Hydrogen-enriched natural gas is a promising low-carbon fuel in combustion devices. To better assess its feasibility from the extinction prevention point of view, the extinction of near-limit premixed hydrogen-methane/air flames over a wide range of equivalence ratios was measured using the single-flame counterflow configuration. Results showed that the hydrogen addition resulted in a greater extinction stretch rate. Further analysis demonstrated that the extinction stretch rate of premixed hydrogen-methane/air flames linearly correlated with the corresponding reference flame speed. Thereby a combustion regime map diagram, separating the burning and extinction, was sketched. In addition, critical extinction Damkӧhlor number of premixed hydrogen-methane/air flames was investigated and it was found to be insensitive to the hydrogen addition and equivalence ratio. Finally, the hydrogen addition effect and the corresponding extinction response were assessed for two scenarios, 1) constant thermal load (gas turbine, gas-fired boilers, etc.), and 2) constant fuel injection pressure (gas stove, oven, etc.). The results indicated that H2 addition promoted the combustion safety by increasing the extinction stretch rates, but an allowable H2 variation window existed when considering the unexpected high-temperature damage of the burners. The allowable H2 variation window of Scenario 1 was found much broader than that of Scenario 2.

Influence of venting coefficient on disastrous effects of aluminium powder explosions

Aluminium powder has a very high risk of explosion. To clarify the disastrous effects of the overpressure and high temperatures during an aluminium powder explosion in a constrained space and the distribution of the outdoor safe distance, the explosion and venting processes of aluminium dust in a large-scale building were investigated under different venting coefficients, Kv (Kv = Av/Ap), using computational fluid dynamics (CFD). The results show that although an increase in the venting coefficient can reduce the indoor overpressure and explosion temperature, it can also increase the distance up to which the outdoor overpressure and high temperature can cause damage. Moreover, the distance up to which explosion overpressures can be harmful to personnel and buildings increases with an increase in the venting coefficient. Hence, the safe outdoor distance may be more than 1.5–2 times the fire safe distance listed in the Chinese Code for fire protection design of buildings. The high-temperature damage caused by the explosion also increases with an increase in the venting coefficient. Therefore, the current explosion safety protection distances for aluminium powder production sites need to be revised.

Mitigation of High-Temperature Damage by Application of Kaolin and Pinolene on Young Olive Trees (Olea europaea L.): A Preliminary Experiment to Assess Biometric, Eco-Physiological and Nutraceutical Parameters

Various products are used to mitigate the negative effects of abiotic stress in olive trees. The aim of the research was to examine an anti-transpirant product (Vapor Gard®, V) and a kaolin- based product (Manisol, K) effect on the growth of two-year-old olive tree seedlings under high temperature. The study was conducted in a greenhouse on trees of a native cultivar of Campania (cv. Salella) grown in pot during the growing season from May to September 2020. The experimental design included two products: di-1-p-menthene (product V) and kaolin (product K), applied five times at 20 day intervals compared with a control. The following biometric, physiological, and nutraceutical parameters were evaluated: stomatal conductance, chlorophyll a fluorescence, Soil Plant Analysis Development (SPAD) index, relative water content (RWC), shoots growth, total leaf area per plant, trunk cross-sectional area, dry matter partitioning, total polyphenols, and antioxidant activity. The results obtained showed that the application of di-1-p-menthene (V) was able to induce a significant improvement of shoots growth (+37.22%) and trunk cross-sectional area (+46.60%) and a reduction of the stomatal conductance and an increase of leaf RWC values. Application with kaolin had positive effects on the total polyphenol content, with an increase over the control of 240.33% and higher antioxidant activity values. Further studies are necessary to determine the effect of these products on the biometric, physiological and nutraceutical parameters of mature olive trees cultivated in open field conditions.

Investigation of mechanical and energy evolution characteristics for sandstone after high temperature damage under cyclic loading

During the production of underground engineering, investigating the mechanical behaviors of rock materials after high temperature damage is of great importance for controlling the stability of the underground structure. In this paper, for revealing the deformation and energy evolution laws of rock materials after high temperature damage under cyclic loading, a series of uniaxial compressive and cyclic loading experiments were conducted on sandstone after various high temperature damages, i.e., 200, 300, 400, 500, 600, 700, 800, and 900°C, to study the effect of high temperature on primary wave velocity, microstructure, deformation, strength, energy, etc. It can be observed that the primary wave velocity and microstructure weakened seriously with the development of high temperature damage and the uniaxial compressive strength of samples increases toward the maximum value with a high temperature damage of 300°C and then decreases gradually. The energy proportion index was established to characterize the influence of high temperature damage and cyclic stress levels on energy evolution laws of samples. With an increase in temperature, compared with input energy, elastic strain energy proportion decreases and dissipated energy proportion rises up, which indicate that the property of samples transforms from elasticity to plasticity. Finally, the variation laws between the burst tendency of the sample and high temperature damage were well described by presenting the average elastic energy index, which provides references for studying failure characteristics of rock materials.

Hot damage evolution in a high strength aluminum alloy during hot forming: a study using the Gurson–Tvergaard–Needleman model

The investigation on the formability of 7075-T6 aluminum alloy at elevated temperatures is significant due to its low plasticity at room temperature. Meso-Damage mechanics suggests that the growth and accumulation of micro-voids is an important factor that leads to material damage, fracture, and affects its formability. In this work, the Gurson–Tvergaard–Needleman (GTN) model was used to investigate the damage evolution of the 7075-T6 aluminum alloy during the hot forming process. The effects of different temperatures and strain rates on the formability were investigated through uniaxial hot tensile tests. The parameters of the Gurson–Tvergaard–Needleman (GTN) model were inverse-calibrated using the Central Composite Design (CCD)-Response Surface Method (RSM)-Genetic Algorithm (GA). Control variable method was used to explore the effect of each damage parameter on the fracture initiation and evolution. The results showed that the calibrated Gurson–Tvergaard–Needleman (GTN) model well predicted the high-temperature damage of the 7075-T6 aluminum alloy at 300–450 °C. Predicted necking and fracture volume fractions of voids were less than 3% error from experimental results. Initial void volume fraction (f0) had little effect on damage. Increasing void nucleation volume fraction (fN) significantly advanced the necking and fracture of the material. An increase in the critical void volume fraction (fC) and fracture void volume fraction (fF) resulted in higher peak stresses and fracture strains.

Comparative Study of Unheated and Heated Rubies from Myanmar

A batch of unheated and heated rubies from Myanmar were obtained from a gemstone processor in Thailand. The gemmological characteristics, chemical composition characteristics, infrared spectrum characteristics and UV-Vis absorption spectrum characteristics were tested and analyzed, so as to obtain the characteristics of the rubies after heat treatment and distinguish them from the unheated rubies from Myanmar. The test results showed that a large number of secondary melt inclusions were found in the heated rubies, while only mineral crystal inclusions and fluid inclusions were observed in the unheated rubies. In terms of chemical composition characteristics, the average content of Ti element in heated rubies is about 1 000 ppm higher than that in the unheated rubies, and the average content of Fe element in heated rubies is about 100 ppm lower than that in the unheated rubies. Absorption peaks of daspore, structural water and free water can be detected in unheated rubies, but these characteristic absorption peaks can not be detected in heated rubies due to the damage of high temperature. Compared with unheated rubies, the fluorescence peak of heated rubies near 694 nm is stronger and sharper.

High-temperature compressive performance of the pre-impacted 2D-C/SiC composites: Coupling effect of pre-impact energy, temperature, temperature-keeping duration, and strain rate

Two-dimensional carbon fiber reinforced silicon carbide (2D-C/SiC) composites are well-known for the high-temperature performance in aeronautical and aerospace fields, but they are susceptible to foreign object damage in service. Therefore, the high-temperature performance of pre-impacted 2D-C/SiC is closely connected with flight security. In this study, the pre-impact testing was conducted using a stress-reversal split Hopkinson bar, and the pre-impact energies were set from 0.1J to 0.9J. Subsequently, the pre-impacted specimens were heated for a period in the temperature-keeping procedure from 20 °C to 1600 °C. Oxidation kinetics of the pre-impacted 2D-C/SiC specimens were obtained based on the weight loss-temperature trends. Finally, the specimens were compressed under high temperatures at the strain rates from 10−4/s to 1000/s, so the residual compressive strength (RCS)-temperature trends were achieved. Hence, the correlation between the weight loss and the RCS was established. Interestingly, the pre-impact strengthening effect on the compressive strength was found. The results revealed that the RCS of 2D-C/SiC is affected by various parameters, providing new sights into the high-temperature damage tolerance of ceramic matrix composites.

High temperature damage development in Ni-alloy/steel dissimilar metal welds

ABSTRACT The development of high-temperature damage in Ni-alloy/steel dissimilar metal welds and its influence on creep-rupture (CR) times and creep-fatigue (CF) endurances is examined. The importance of a systematic and detailed post-test examination of the damage generated in x-weld microstructures is emphasised, and available evidence for Alloy-617/1%Cr-steel welds at 550°C and Alloy-617/10%Cr-steel welds at 575°C is characterised. CR and CF weld strength factors for the two DMWs are determined by the respective kinetics of microstructural developments adjacent to the fusion line and in the FG/ICHAZ of the steel. While the influence of near-weld microstructural evolution in the steel part of Alloy-617/1%Cr-steel DMWs is similar for both CR and CF damage development at 550°C, the same cannot be concluded for Alloy-617/10%Cr-steel DMWs at 575°C. Creep-fatigue damage in Alloy-617/10%Cr-steel DMWs initially develops in the over-tempered parent material with an increasing influence of FG/ICHAZ CF damage generation with reduced strain range.

Numerical Study on Damage Zones Induced by Excavation and Ventilation in a High-Temperature Tunnel at Depth

Geothermal power is being regarded as depending on techniques derived from hydrocarbon production in worldwide current strategy. However, it has artificially been developed far less than its natural potentials due to technical restrictions. This paper introduces the Enhanced Geothermal System based on Excavation (EGS-E), which is an innovative scheme of geothermal energy extraction. Then, based on cohesion-weakening-friction-strengthening model (CWFS) and literature investigation of granite test at high temperature, the initiation, propagation of excavation damaged zones (EDZs) under unloading and the EDZs scale in EGS-E closed to hydrostatic pressure state is studied. Finally, we have a discussion about the further evolution of surrounding rock stress and EDZs during ventilation is studied by thermal-mechanical coupling. The results show that the influence of high temperature damage on the mechanical parameters of granite should be considered; Lateral pressure coefficient affects the fracture morphology and scale of tunnel surrounding rock, and EDZs area is larger when the lateral pressure coefficient is 1.0 or 1.2; Ventilation of high temperature and high in-situ stress tunnel have a significant effect on the EDZs scale; Additional tensile stress is generated in the shallow of tunnel surrounding rock, and the compressive stress concentration transfers to the deep. EDZs experiences three expansion stages of slow, rapid and deceleration with cooling time, and the thermal insulation layer prolongs the slow growth stage.