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The use of a rapid heating method to achieve heterogeneity of Mn in medium-manganese steel and improve its comprehensive performance has been widely studied and these techniques have been widely applied. However, the heating rate (from α to γ) has not received sufficient attention with respect to its microstructure-evolution mechanism. In this study, the effect of heating rate on the microstructure evolution and hardness of heterogeneous medium-manganese steel was investigated by using X-ray diffraction (XRD), scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), transmission electron microscopy (TEM) and DICTRA simulation. The results showed that the Mn distribution was heterogeneous in the initial microstructure of pearlite due to strong partitioning of Mn between ferrite and cementite. At low heating rates (<10 °C/s), the heterogeneity of Mn distribution was diminished to some extent due to the long-distance diffusion of Mn in high-temperature austenite. Contrastingly, at high heating rates, the initial heterogeneity of the Mn element could be largely preserved due to insufficient diffusion of Mn, which resulted in more ghost pearlite (GP: pearlite-like microstructure with film martensite/RA). Moreover, the high heating rate not only refines the prior austenite grain but also increases the total RA content, which is mainly composed of additional film RA. As the heating rate increases, the hardness gradually increases from 628.1 HV to 663.3 HV, due to grain refinement and increased dislocation density. Dynamic simulations have also demonstrated a strong correlation between this interesting microstructure and the non-equilibrium diffusion of Mn. [ABSTRACT FROM AUTHOR]

Sugarcane bagasse is rich in cellulose and lignin, and the recycling of bagasse has become an important research field with the increasing global concern for sustainable development and environmental protection. In this paper, TG-MS-FTIR equipment was used to analyze the pyrolysis characteristics of bagasse from Guangxi under different heating rates and different atmospheres, which is conducive to the reuse of bagasse from the waste gas produced in the sugar plant. The results showed that the pyrolysis rate of sugarcane bagasse in the air atmosphere was faster than that in the nitrogen atmosphere and showed a double-peak trend, and the Coats–Redfern computational model could more accurately simulate the process of pyrolysis. The lower heating rate could overcome the heat transfer hysteresis phenomenon in the process of pyrolysis. In the air atmosphere, the contact time between oxygen and volatile products was shorter due to the high heating rate, and more and more complex species were precipitated at 10 °C/min than at 20 °C/min. In the nitrogen atmosphere, it was favorable to produce more kinds and quantities of gas products, because it did not react with oxygen. FTIR detected CH4, CO, H2O, CO2, C-O-C, and C=O during pyrolysis in nitrogen, and some of C-O-C and C=O were cracked into small molecule compounds at high temperature. [ABSTRACT FROM AUTHOR]

This work investigated the influence of microwave sintering on the BaCe 0.2 Zr 0.7 Y 0.1 O 3-δ phase, incorporating 2 mol% or 4 mol% NiO as sintering aid. X-ray diffraction analysis of perovskite phase detected a rhombohedral structure under both sintering heating rates (280 and 500 °C/min), also exhibiting the presence of a second phase deficient in Ba with Ni incorporated into the structure, replacing part of the Zr. Raman analysis indicated no distortions in the perovskite structure, independent of the rates and NiO concentrations. The efficacy of NiO addition as a sintering aid was demonstrated by high densification of the samples, exceeding 97 % relative density. Detailed analysis of structural, microstructural, and conductivity properties revealed that microwave sintering, particularly using a heating rate of 500 °C/min, yielded superior results compared to conventional sintering. The enhanced electrical response was attributed to a higher concentration of structural defects, oxygen vacancies, in the microwave-sintered samples, evidenced by the band at 630 cm−1 in the Raman spectrum. Among these, the BCZY sample with 2 mol% NiO, sintered under these conditions, stood out as the most promising, showcasing not only high density but also a uniform microstructure and appreciable electrical conductivity. [ABSTRACT FROM AUTHOR]

The impact of rapid heating on sintering is currently getting a growing scientific interest. Previous results have shown that when considering 90 nm‐sized 3 mol% yttria‐stabilized zirconia (3YSZ) powder the heating rate effect on densification is not detectable, whereas it is huge when using finer powder (≈20 nm, specific surface area, SSA = 30–60 m2 g−1). Herein, we investigate the fast firing of ≈40 nm 3YSZ powder (SSA = 16 m2 g−1) and compare it with conventional sintering. The results show that the heating rate has a modest effect on the final density with improvements always below 2%–3% in terms of relative density. The relatively good match between fast firing and the densification behavior predicted by the master sintering curves agrees with the observed microstructural evolution, where fast‐firing provides only a modest effect on the pore size. Finally, it is shown that the heating rate does not impact the dynamics of closed pore formation. [ABSTRACT FROM AUTHOR]

Briquette production method is vital to improving its strength and permeability in physical simulation test of coal mine gas disasters. This study adopts the Horsfield dense packing theory to optimize the ratio of briquette materials and investigates the mechanical-seepage characteristics, molecular and pore structure of hot-pressed briquettes under different heating rates. Results show that as the heating rate increases, the proportion of C1s elements and the contents of alcohol, C--O/C--OH, aromatic hydrocarbons and C--C/C--H in functional groups in the molecular structure of hot-pressed briquettes show a fluctuating pattern of initial increase, subsequent decrease and final increase; the uniaxial compressive strength first increases and then decreases, while the initial permeability first decreases and then increases. The optimum heating rate is 5 ²C/min. This study offers references to improving the similarity between briquette and raw coal. [ABSTRACT FROM AUTHOR]

Zirconium alloys are widely used in nuclear water reactors as cladding materials. The cladding materials will absorb hydrogen from high temperature water during the operation of nuclear reactor. In cladding tubes, it has been common sense that circumferential hydrides form without stress, while radial hydrides can form when the hydrides are reoriented under stress loading. In this study, we found that a high heating rate can result in hydride reorientation behavior even without stress. At elevated heating rates, the zirconium alloy clad tube developed a non-uniform strain gradient along the direction of heat conduction. Hydrogen atoms migrate preferentially to areas of elevated stress and precipitate as hydrides that are perpendicular to the direction of tensile stress, resulting in the formation of radial hydrides that appear as "sun spots" macroscopically. Additionally, the high heating rate disrupts the {0001}α∥{111}δ, <11–20>α∥<110>δ orientation relationship between the hydride and the substrate, which potentially facilitates crack propagation. [ABSTRACT FROM AUTHOR]

To investigate combustion thermodynamics and kinetics for different coal rank, TG-DSC test was conducted on long-flame coal (LFC), gas-fed coal (GFC), and coke coal (CC) under different heating rates. Based on the DSC curve, the combustion process of coal can be divided into five stages: dehydration and desorption stage, chemical adsorption stage, transition stage, combustion stage, and burnout stage. With the increase in heating rate, the combustion characteristic parameters and the exothermic quantity show an upward trend. Under the consistent condition of the heating rate, the coal rank is positively correlated with its characteristic temperature, and negatively correlated with the maximum exothermic quantity. The kinetics experimental results show that the differential method exhibited higher fitting coefficients compared to the integral method, indicating its greater reliability in calculating results. Moreover, the activation energy increased with the increase of the coal rank under the same heating rate. CC has the highest activation energy, followed by GFC and LFC. These findings provide data support for the combustion law of similar coal types. [ABSTRACT FROM AUTHOR]

Biomass pyrolysis is the most effective process to convert abundant organic matter into value-added products that could be an alternative to depleting fossil fuels. A comprehensive understanding of the biomass pyrolysis is essential in designing the experiments. However, pyrolysis is a complex process dependent on multiple feedstock characteristics, such as biomass consisting of volatile matter, moisture content, fixed carbon, and ash content, all of which can influence yield formation. On top of that, product composition can also be affected by the particle size, shape, susceptors used, and pre-treatment conditions of the feedstock. Compared to conventional pyrolysis, microwave-assisted pyrolysis (MAP) is a novel thermochemical process that improves internal heat transfer. MAP experiments complicate the operation due to additional governing factors (i.e. operating parameters) such as heating rate, temperature, and microwave power. In most instances, a single parameter or the interaction of parameters, i.e. the influence of other parameter integration, plays a crucial role in pyrolysis. Although various studies on a few operating parameters or feedstock characteristics have been discussed in the literature, a comprehensive review still needs to be provided. Consequently, this review paper deconstructed biomass and its sources, including microwave-assisted pyrolysis, and discussed the impact of operating parameters and biomass properties on pyrolysis products. This paper addresses the challenge of handling multivariate problems in MAP and delivers solutions by application of the machine learning technique to minimise experimental effort. Techno-economic analysis of the biomass pyrolysis process and suggestions for future research are also discussed. [ABSTRACT FROM AUTHOR]

In concrete engineering, high temperatures at varying heating rates significantly affect the stability of concrete structures. In this paper, the dynamic tensile characteristics were investigated on concrete specimens subjected to heating rates ranging from 2 to 40 °C/min, using the digital image correlation (DIC) method. The results reveal a critical heating rate threshold, between 5 and 10 °C/min, which marks a shift in the influence of heating rates on both physical and dynamic tensile properties. Below this threshold, changes are minimal, but beyond it, significant effects are observed. As the heating rate increases, longitudinal wave velocity, density, and mass decrease, while porosity increases. Both wave velocity and dynamic tensile strength exhibit a linear decline with increasing heating rates, whereas porosity increases linearly. Additionally, when the heating rate surpasses the threshold, the angle between the failure surface and the loading bar increases, and the maximum principal strain in the direction perpendicular to the loading direction, measured on the specimen's plane, decreases. Initial failure occurs at the location of highest strain, typically along the central axis of the specimen. These findings suggest that rapid heating should be avoided in concrete engineering to maintain structural integrity. However, rapid heating could be used to break and reuse concrete materials. [ABSTRACT FROM AUTHOR]

In the process of heat treatment of 8620 low alloy steel, the heating rate is a critical parameter that must be carefully controlled to achieve the desired combination of microstructural features, mechanical properties, and corrosion resistance while simultaneously ensuring process efficiency and cost-effectiveness. This study investigates, for the first time, the microstructural evolution and electrochemical properties of 8620 steel under identical quenching and tempering heat treatment routes with slow-rate (SR) and fast-rate (FR) heating rates. Microstructural analysis revealed martensitic phases for SR, while FR exhibited a dual-phase microstructure containing ferrite. Upon tempering, for both samples, the martensite transformed into tempered martensite, with tempered (Temp) FR exhibiting around 50% smaller ferrite grains. Mechanical testing indicated that SR had 17% higher hardness than FR, although hardness decreased after tempering by 22% (SR) and 17% (FR). All electrochemical tests indicated that the as-quenched SR exhibited significantly superior corrosion resistance than FR. For instance, the polarization resistance of SR was 440 Ω higher than that of the FR samples. Tempering resulted in a considerable decrease in corrosion resistance for Temp SR, whereas Temp FR improved. Electrochemical characterization revealed Temp FR displayed close-to-ideal capacitive behavior and low double-layer capacitance, indicating enhanced overall corrosion resistance.

This study investigates the fracture characteristics and damage mechanism of granite after treatment under different heating rates. The cracked straight-through Brazilian disc(CSTBD)specimen was used for high-temperature treatment with four heating rates under four sets of heating temperatures. The Brazilian splitting experiments were carried out using electro-hydraulic servo press after cooling down to room temperature, and the static fracture process was analyzed to investigate the effect of heating rate on the fracture mechanical properties of specimens. The results show that: (1) Granite treated at different high temperatures shifted from brittle to ductile damage. (2)The peak damage load of granite treated with different heating rates at the same temperature decreased with the increase of heating rate. At the same temperature, the increase of heating rate doesn't lead to obvious difference in the apparent color of granite, but with gradual increase of apparent cracks. (3)At different heating rates, the longitudinal wave velocity and elastic modulus at 200 ℃ and 400 ℃ show subtle changes, yet at 600 ℃ and above, the longitudinal wave velocity and elastic modulus decrease significantly with the increase of heating rate. (4) The fracture toughness of granite shows gradual decay with the increase of temperature. At the same temperature, type I fracture toughness of granite specimens decreases with the increase of heating rate. At 400 ℃, heating rate exerts maximum influence on the fracture toughness of granite.

Pyrolysis is an effective way for the harmless treatment of oily sludge. The composition, physicochemical properties, and pyrolysis of oily sludge were experimentally studied in the present study. The Starink and Coats-Redfern methods were used to analyze the pyrolysis kinetics of oily sludge. Pyrolysis of oily sludge is divided into four stages: water evaporation stage, light component evaporation stage, heavy component pyrolysis stage, and final pyrolysis stage. The light component evaporation and heavy component pyrolysis stages are the main stages of medium-temperature pyrolysis. The pyrolysis characteristic parameters under heating rates of 10, 20, 30, and 40 K/min were obtained, and the effects of heating rates on the pyrolysis characteristics of oily sludge were discussed. The results show that with the increase in heating rate, the temperature range of each stage expands, and the temperature of the pyrolysis peaks also increases, with an average increase of 14.88%. The activation energies of the main pyrolysis stages obtained by the Starink method and Coats-Redfern method are consistent. In the light component evaporation stage, the activation energies obtained by the two methods are 61.93kJ/mol and 68.6kJ/mol, while the activation energies are 294.88kJ/mol and 367kJ/mol in the heavy component pyrolysis stage. The pyrolysis mechanism functions are obtained, and the pyrolysis kinetic equations under 10, 20, 30, and 40 K/min were constructed and validated by comparison with the results of the calculated properties and experimental measurement. This study can provide a better insight into the heat and mass transfer processes of oily sludge in pyrolysis reactors for further development and optimization. [ABSTRACT FROM AUTHOR]

The effect of thermal process parameters on the alloying of Al–10Mg (wt%) system has been studied in molecular dynamics approach. Five distinct values of heating rate have been considered for Al and Mg nanoparticles (NPs) to melt, coalesce followed by identical cooling. Detailed investigation of Al-Mg NPs alloying has been done in terms of alloying temperature, atomic migration, coalescence kinetics and mechanical characteristics for various heating rates were carried out. Prior to the alloying simulation, component melting simulations of Al and Mg single particles (SPs) were conducted to determine the melting temperature of NPs and to inspect their individual thermo-stability. From the change in potential energy, its evident that the melting temperature of the component NPs significantly depends on heating rates. Following the component melting, alloying simulations were conducted in three distinct phases: (i) heating, (ii) relaxation, and (iii) cooling and solidification. Following the solidification, uniaxial tensile test simulation was done on a block cut to characterise the mechanical behaviour in context to dislocation analysis, HCP evolution, stacking fault analysis and corresponding stress–strain relationship. Obtained results showed a substantial affiliation of heating rates and coalescence kinetics but showed minimal effect on mechanical properties. [ABSTRACT FROM AUTHOR]

Energy storage capacitors for advanced pulse power systems and high-power electric devices is a kind of important electronic components, the demand continues to grow, specifications are constantly being upgraded, and performance boundaries are continuously being pushed. Multilayer ceramic capacitors (MLCCs) for energy storage applications have received increasing attention due to the advantages of ultralow equivalent series inductance, equivalent series resistance, good frequency characteristics, strong voltage overload ability, and stable operability at high temperatures. However, the relatively low energy storage density significantly limits its broader applications. Here, 0.4Ba 0.55 Sr 0.45 TiO 3 -0.4Bi 0.5 Na 0.5 TiO 3 -0.2SrZrO 3 (0.4BST-0.4BNT-0.2SZ) relaxor ferroelectric MLCCs are prepared at different heating rates. Excellent recoverable energy storage density of 10.3 J cm−3 and high energy efficiency of 93 % are achieved in fast-fired MLCCs under the electric field of 106.3 V μm−1. The impedance spectroscopy and thermally stimulated depolarization current technologies are employed to investigate the conductance mechanism of MLCCs, and the results can explain the effect of heating rate on the performance of MLCCs. In addition, the charge-discharge performances of fast-fired MLCCs are also thoroughly investigated, exhibiting great thermal and fatigue stability. [ABSTRACT FROM AUTHOR]

In order to explore the improvement of thermal properties of phase change materials on wall, 35% Na2CO3·10H2O/52. 5% Na2HPO4·12H2O/5% boron nitride nanoparticles/7. 5% expanded graphite composite phase change materials were prepared by eutectual method, which were made into blocks and placed in different positions of gypsum board. A phase change wall which could be used to adjust indoor thermal comfort was constructed. The thermal response characteristics of the wall at different locations or at different temperatures of heat source were experimentally studied, and the reduction of CO2 emission was evaluated. The results show that with the increase of heating distance and the decrease of heat source temperature, the indoor heating rate gradually decreases, and the time-duartion of thermal comfort correspondingly increases. With the heating distance of 30 cm and heating temperature of 37 ℃, the time-duration of thermal comfort of sandwiched phase change gypsum boards at interior side reaches 1 980 s, which is 20 s longer than that of sandwiched phase change gypsum boards at exterior side. The CO2 emission can be reduced by 379. 36 kg within the recylic time of 2 371 days. Therefore, when the heating distance is longer and the heat source temperature is lower, the sandwiched phase change gypsum boards at interior side is more conductive to delaying the rising rate of the room temperature and reducing CO2 emission. [ABSTRACT FROM AUTHOR]

In the process of heat treatment of 8620 low alloy steel, the heating rate is a critical parameter that must be carefully controlled to achieve the desired combination of microstructural features, mechanical properties, and corrosion resistance while simultaneously ensuring process efficiency and cost-effectiveness. This study investigates, for the first time, the microstructural evolution and electrochemical properties of 8620 steel under identical quenching and tempering heat treatment routes with slow-rate (SR) and fast-rate (FR) heating rates. Microstructural analysis revealed martensitic phases for SR, while FR exhibited a dual-phase microstructure containing ferrite. Upon tempering, for both samples, the martensite transformed into tempered martensite, with tempered (Temp) FR exhibiting around 50% smaller ferrite grains. Mechanical testing indicated that SR had 17% higher hardness than FR, although hardness decreased after tempering by 22% (SR) and 17% (FR). All electrochemical tests indicated that the as-quenched SR exhibited significantly superior corrosion resistance than FR. For instance, the polarization resistance of SR was 440 Ω higher than that of the FR samples. Tempering resulted in a considerable decrease in corrosion resistance for Temp SR, whereas Temp FR improved. Electrochemical characterization revealed Temp FR displayed close-to-ideal capacitive behavior and low double-layer capacitance, indicating enhanced overall corrosion resistance. [ABSTRACT FROM AUTHOR]

The heat-aging process, a practical aging technology that not only improves the comprehensive performance of Al alloys but also reflects the requirements of short processes, has an extremely practical significance. The effects of the heating rate and termination temperature on the "heat-aging" behavior of a spray-deposited AlZnMgCu alloy hot-extruded plate were investigated using hardness, electrical conductivity, room-temperature tensile strength, exfoliation corrosion experiments, and transmission electron microscopy microstructure (TEM) observation. The results show that as the termination temperature increases, the hardness of the spray-deposited AlZnMgCu alloy first increases to a peak and then rapidly decreases, while the electrical conductivity continues to increase. The increase in the heating rate improves the peak hardness corresponding to the termination temperature. The heat treatment process of heating at a speed of 20 °C/h to 200 °C after the spray deposition has similar mechanical and corrosion resistance properties to the RRA process and can effectively reduce the heating time from 40 h to 8 h, thus establishing a heat treatment process for spray-deposited AlZnMgCu alloy extruded plate with high aging efficiency. [ABSTRACT FROM AUTHOR]

Supported catalyst synthesis involves pretreatment (drying, reduction) of metal complexes to form metal nanoparticles. This study has been undertaken to explore the effect of reduction temperature, heating rate, and water partial pressure on final particle size of Pt and Pd supported on a total of four carbon and oxide supports. Supported nanoparticles were synthesized by strong electrostatic adsorption (SEA) and dry impregnation (DI); the former method was hypothesized to yield greater nanoparticle stability in thermochemical reducing environments stemming from the strong interaction of the precursor with the support during impregnation. Reduced samples were characterized by in-situ and ex-situ XRD and STEM. The DI-derived samples generally showed an expected increase of particle size with increased reduction temperature, and severe particle coalescence in humid hydrogen, while the SEA-derived samples did not sinter at the elevated reduction temperatures (up to 500 °C) and were remarkably stable in the humid reducing environment. [ABSTRACT FROM AUTHOR]

The aim of this study is to dry whole strawberries, which are a sensitive and high value-added food, with different heating rate approach in different drying stages developed to overcome the problems encountered in microwave freeze-drying (MFD). To do this, a specially designed microwave (2450 MHz) freeze-drying system developed in our laboratory was used. Internal temperatures at two different whole strawberries which are one at the center and one at the edge of the basket were recorded during drying experiments by using a signal conditioner and fiber optic probes. Drying experiments were carried out until a moisture content of below 10% by weight was attained. Heating rates determined by preliminary trials of 0.035 °C/min and 0.2 °C/min were applied to whole strawberries in the primary and secondary drying stages, respectively. The quality parameters of microwave freeze-drying and freeze-dried whole strawberries were compared. In this context, dried strawberries were subjected to some physical (moisture content, water activity, texture, and color) and chemical (vitamin C, total phenolic content, and antioxidant capacity) analyses. Microwave freeze-drying (MDF) was able to preserve the vitamin C content of all strawberries by approximately 55% while yielding a final product of substantially similar quality to freeze-drying (FD). [ABSTRACT FROM AUTHOR]

This study investigates the impact of dust on radiation over the Arabian Peninsula (AP) during the reported high, low, and normal dust seasons (March–August) of 2012, 2014, and 2015, respectively. Simulations were performed using the Weather Research and Forecasting model coupled to a Chemistry module (WRF‐Chem). The simulated seasonal horizontal and vertical dust concentrations, and their interannual distinctions, match well with those from two ground‐based AERONET observations, and measurements from MODIS and CALIOP satellites. The maximum dust concentrations over the dust‐source regions in the southern AP reach vertically upto 700 hPa during the high dust season, but only upto 900–950 hPa during the low/normal dust seasons. Stronger incoming low‐level winds along the southern Red Sea and those from Iraq bring in higher‐than‐normal dust during the high dust summers. We conducted a sensitivity experiment by switching‐off the dust module to assess the radiative perturbations due to dust. The results suggest that active dust‐module improved the fidelity of simulated radiation fluxes distributions at the surface and top of the atmosphere vis‐à‐vis Clouds and the Earth's Radiant Energy System (CERES) measurements. Dust results in a 26 Wm−2 short‐wave (SW) radiative forcing in the tropospheric‐column over the AP. The SW radiative forcing increases by another 6–8 Wm−2 during the high dust season due to the increased number of extreme dust days, which also amplifies atmospheric heating. During extreme dust days, the heating rate exhibits a dipolar structure, with cooling over the Iraq region and warming of 40%–60% over the southern‐AP. Plain Language Summary: Dust is the dominant tropospheric aerosol in the Arabian Peninsula (AP). High dust loading and prolonged episodes are crucial in dust‐radiation feedback mechanisms. WRF‐Chem successfully simulated the spatial distribution of dust aerosols and their underlying dust‐transport mechanisms over the study region. Model results reveal that dust aerosols influence surface and atmospheric radiation, resulting in cooling at the surface and warming in the overlying atmosphere. Extreme dust days exhibit significant heating in the south and cooling in the north. This study enhances our understanding of dust‐aerosol interactions with regional meteorology, aiding in better weather and climate prediction in dust‐laden regions like the AP. Key Points: This study explores the influence of dust aerosols on radiative fluxes over the Arabian Peninsula (AP)WRF‐Chem model effectively captures the physical mechanisms of dust transportExtreme dustiness significantly modulates the radiative fluxes, thereby exerting a notable influence on the atmospheric heating rates [ABSTRACT FROM AUTHOR]

The non-equilibrium melting of Na crystals at high heating rates and the evolutions of the atomic clusters are studied by the MD method and PTM analysis. Results show that as the heating rate rises from 1 × 1011 K/s to 2 × 1013 K/s, the non-equilibrium melting temperature of Na increases non-linearly from 417 K to 480 K, the melting temperature difference experienced increases from 7 K to 27 K, while the melting time decreases from 70 ps to 1 ps. Through the PTM analysis, it is found that some BCC clusters transform into the disordered Other clusters through intermediate HCP and FCC clusters with increasing temperature, and the BCC cluster's reduction rate and the Other cluster's growth rate are getting slower with increasing heating rate. There is a good correspondence between the evolutions of the atomic clusters, the changes of macroscopic physical parameters, and the peaks and valleys of RDF with temperature. [ABSTRACT FROM AUTHOR]

Previous studies on the austenite grain growth were mostly based on a fixed temperature, and the relationship between the austenite grain and austenitizing parameters was fitted according to the results. However, there is a lack of quantitative research on the austenite grain growth during the heating process. In the present work, based on the diffusion principle of the controlled Ti microalloying element, the diffusion process of carbonitrides containing Ti during the heating process was analyzed. Combined with the precipitation model and the austenite growth model, the prediction model of austenite grain growth of Ti microalloyed steel during different heat treatment processes was established. The austenite grain size versus the temperature at four different heating rates of 0.5, 1, 10, 100 °C/s was calculated. The grain growth behavior of austenite during the heating process of Ti microalloyed steel was studied by optical microscope, scanning electron microscope and transmission electron microscope. The experimental data of the austenite grain size was in good agreement with the calculation by the proposed model, which provides a new idea for the prediction of austenite grain size in non-equilibrium state during the heating process. In addition, for Ti-containing microalloyed steels, the austenite grain size increased with the increasing heating temperature, while it changed little by further prolonging isothermal time after certain heating time, which was related to the equilibrium degree of the precipitation and the dissolution of Ti element. The austenite grain coarsening temperature of the tested Ti microalloyed steel was estimated within 1100~1200 °C. [ABSTRACT FROM AUTHOR]

In this research, a novel method to improve the particle size and content of Y2BaCuO5 (Y-211) in YBa2Cu3O7 − x (YBCO) bulks was demonstrated. The single-domain YBCO bulks (20 mm in diameter) have been fabricated employing the RE+011 TSIG technique with different heating rates during the liquid phase infiltration (LPI) stage. The various heating rates on Y-211 size and its content in the final YBCO samples has been investigated in detail. The findings suggest that the average size of the Y-211 particles in the Y-123 matrix initially decreases followed by an increase, while its volume fraction gradually decreases with increasing heating rate. Furthermore, it is observed that the levitation force and the trapped fields exhibit an initial increase followed by a subsequent decrease as the heating rate increases. Among all the samples, sample S3 (heating rate of 30 °C/h) has the best magnetic levitation force and trapped field performances at 77 K, i.e., the largest values are of 45.3 N and 0.41 T, respectively. The results suggest that, while employing the RE+011 TSIG technique for YBCO bulk fabrication, the average size and volume fraction of Y-211 particles in the final sample can be further enhanced by controlling the heating rates during the LPI stage, obviating any need for chemical refining agents. [ABSTRACT FROM AUTHOR]

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This study explored the impact of pyrolysis heating rates ranging from 1 to 20 K min−1 (final temperature 500 °C) on the porosity of resorcinol-formaldehyde based carbonaceous xerogels soft-templated with Pluronic F-127. We primarily utilized thermoporometry (differential scanning calorimetry technique) and, to a lesser extent, conventional nitrogen adsorption at −196 °C to analyze the porosity of the resulting carbons. Additionally, we examined the effects of particle size and the scale of the pyrolysis experiment, comparing a laboratory furnace with a thermal analyzer. At lower heating rates, particularly in a thermal analyzer, mesopores approximately 7–8 nm in size were observed. An increase in the heating rate resulted in larger mesopores, from 7 to 17 nm, widened pore size distribution (PSD), and a rise in mesopore volume from 0.21 to 0.53 cm3 g−1. Higher heating rates (> 5 K min-1) also accelerated the decomposition of the Pluronic F-127, leading to fast gas release, which subsequently caused cracking of the carbon skeleton and widening of the pores. Pyrolysis heating rate had no significant effect on the degree of graphitization in the pyrolyzed samples. Particle size showed minimal influence on porosity when xerogels were pyrolyzed at either the minimal or maximal heating rates in the thermal analyzer. However, experiments conducted in a laboratory furnace at the lowest heating rate demonstrated that imprecise temperature control and fluctuations can lead to the formation of larger mesopores.

In recent decades, the rising demand for permanent magnetic materials has driven manufacturers to explore substitutes for rare earth elements in response to their fluctuating prices and negative environmental impact. M-type hexaferrites considered as good alternatives and studies have focused on enhancing their magnetic and structural properties through various approaches. In this study, new approach using low heating rate microwave sintering has been applied to investigate the changes on density, microstructure, and magnetic properties of strontium hexaferrite from core to surface. Sintering temperatures of 950 °C, 1000 °C, 1050 °C, and 1100 °C with 10 °C/minute heating rate were applied accordingly. The bulk density, FESEM, XRD and VSM tests were conducted to study materials’ properties. The outcomes of the study showed exponential relationship between density and sintering temperature reaching optimum value of 91.4 % at 1050 °C and then declined slightly at observed to analysis confirmed the magnetoplumbite structure P63/mmc in all samples and high crystallized structure at 1050 °C, with the occurrence of α-Fe2O3 at 1100 °C. Grain growth and crystallization observed to increase at higher sintering temperature with agglomeration while denser and melted boundaries at lower temperatures. Magnetic properties especially remanence magnetization Mr and saturation magnetization Ms fluctuated with sintering temperature achieving optimum values of 28.188 emu/g and 55.622 emu/g at 1000 °C respectively. Coercivity Hc and magnetic energy density BH max recorded optimum values at 1050 °C. The findings emphasize the critical role of microwave sintering in tailoring the properties of strontium hexaferrite for magnetic applications.

This study investigated the impact of two different heating rates (10 and 20 °C/min) on the thermal characteristics of three specific polymers: high-density polyethylene (HDPE), polypropylene (PP) and polyvinylchloride (PVC). A twin-screw extruder was employed to prepare the samples. In order to examine the influence of heating rate, differential scanning calorimetry (DSC) was used. The results of the differential scanning calorimetry (DSC) analysis, including the glass transition temperature (Tg), melting temperature (Tm), enthalpy change (ΔHm) and crystallization temperature (Tc), indicate that the melting temperature and enthalpy drops for polyethylene (PE), polypropylene (PP) and polyvinyl chloride (PVC) when the heating rate increases. Furthermore, there is a minor alteration in the Tc . These studies are also of significant importance for the future of construction, which increasingly emphasizes ecological and sustainable solutions.

The usage of renewable energy is a mitigation phenomenon majorly impacting the power sectors, with biomass being one of the sources directly replacing coal in various applications. This leads to the portrayal of biomass having the potential to be a carbonaceous material, namely the Empty Fruit Bunch (EFB) of oil palm. To increase the characteristics of EFB, it can be converted into carbon-based products through thermochemical processes, such as hydrothermal carbonization. Therefore, this study aimed to compare the characteristics of feedstock and biochar EFB using the TGA method. The heating rate used in this study is 10 - 30°C/min at five °C/min intervals. The effect of heating rate on kinetic parameters and thermal (DTG, TGA) and combustion (T ignition, T burn out) characteristics was also determined. This study carried out the HTC process at temperatures of 210°C and 230°C. The results showed that biochar EFB had a higher ignition, burnout temperature, and activation energy than raw EFB. Ignition temperatures for EFB-HT210°C and EFB-HT230°C were 297°C and 298°C; burnout temperatures for EFBHT210° C, EFB-HT230°C were 407°C and 450° C; and the activation energy for EFB-HT°210C, EFB-HT°230C were 58.84 kJ/mol and 62.16 kJ/mol. Besides the characteristics of biomass, the heating rate also affects combustion. This proved that increased heating rate caused higher ignition and burnout temperature and decreased activation energy. The results also indicated that the difference in heating rate influenced the peak temperature in DTG. [ABSTRACT FROM AUTHOR]

This study investigated austenite formation in a cold‐rolled dual‐phase steel through thermal experiments in a dilatometer and a Gleeble machine, applying various intercritical annealing temperatures and different heating rates in a 60 % cold‐rolled ferrite‐pearlite banded microstructure. The microstructural characterization revealed that the transformation of lamellar pearlite into ferrite and spheroidized cementite aggregates started before the onset of austenite formation. Different degrees of overlap between the recrystallization of ferrite‐pearlite structure and austenite formation processes were observed, depending on the applied heating rates, which affected the austenite formation mechanisms and the microstructure morphology. [ABSTRACT FROM AUTHOR]

Featured Application: Numerical results to determine the fire resistance of ultra-high-strength steel using different heating rates. Ultra-High-Strength Steel (UHSS) offers several advantages over normal carbon steel, promoting exceptional strength, reducing self-weight, improving fire resistance, enhancing durability, and reducing material consumption. These advantages result in cost savings and sustainable engineering construction. The 3D numerical model is based on Geometrical and Materially Nonlinear Imperfection Analysis (GMNIA) and determines the fire resistance of different cross-section columns. The model is validated with experimental tests, with a maximum relative error of 11%. A parametric analysis is presented, based on 252 simulations, assuming three heating rates, two different cross-sections, two different thicknesses, three lengths, and seven load levels. The fire resistance depends on the heating rate, but the critical temperature is almost equal and independent of the heating rate, if one assumes implicit creep in the constitutive material model. The fire resistance decreases with the load level, as expected. The thickness effect of the hollow section is almost negligible in the fire resistance of UHSS columns. The fire resistance decreases more in higher load levels for slender columns. Columns with Circular Hollow Sections (CHSs) generally show higher fire resistance than hybrid columns in longer columns, but the hybrid columns are subject to much higher loads. New design formulas are presented for the critical temperature of UHSS columns, depending on the load level and slenderness of two different cross-sections. [ABSTRACT FROM AUTHOR]

A lab-scale continuous ohmic heating (COH) system was developed, and its performance was studied for pineapple juice heating as a model sample. The effect of independent parameters [°Brix/Acid (unstandardized, 18, 22, 26) and flow rate (80–120 mL/min) of juice and electric field strength (EFS: 25–45 V/cm)] were analysed for responses viz. come-up-time, heating rate (HR) and system performance coefficient (SPC). The full factorial experimental design was used for this study. The results showed that with an increase in °Brix/Acid, the % acidity and electrical conductivity decreased significantly (p < 0.05); thus, the come-up-time to reach 90 °C increased significantly. The HR was significantly (p < 0.05) influenced by °Brix/Acid and EFS but less so by flow rates at higher EFS. The SPC was more than 0.90 and reduced significantly (p < 0.05) with an increase in °Brix/Acid and flow rate. The HR was modeled using a feed-forward back-propagation artificial neural network (ANN) with the best topology of 3, 5, and 1 neurons in the input (independent), hidden, and output (response) layers, respectively. The model performed efficiently, which is evident from the high R2 (0.998) and low RMSE (1.255). Thus, the COH, with its high efficiency and HR, can effectively be used to process fruit juice. [ABSTRACT FROM AUTHOR]

Thermal stability and the kinetics of thermal decomposition of the thermally reduced graphene oxide (TRGO) treated by a pulsed high-frequency discharge in a hydrogen atmosphere have been studied. The modified Hummers method was used for obtaining the initial graphite oxide from graphite powder. Thermal exfoliation of the graphene oxide powder has been done in vacuum conditions with a heating rate of 5–7 degrees per minute to a temperature of 300 °С. TRGO has been treated by pulsed high-frequency discharge in a hydrogen atmosphere for partial graphene hydrogenation (chemical addition of atomic hydrogen) that leads to structural changes in the carbon planes and formation of C–H sp3 bonds. The thermogravimetry analysis measurements of the mass loss have been carried from room temperature to 1000 °C in a nitrogen atmosphere with a nitrogen flow rate of 20 mL/min and different heating rates: 50, 75 100, 125, 150, and 200 K/min, respectively. Kissinger's multiple heating rate method has been used to determine the activation energy for decomposing substances. Activation energies Ea1, Ea2, and Ea3 equal 28, 50, and 148 kJ/mol, respectively, have been compared with the energies of the activation of thermal defunctionalization of multiwalled carbon nanotubes (MWCNTs). The activation energy Ea3 = 148 kJ/mol is close to that of the thermal decomposition of anhydride functional groups in MWCNT. The value of Ea2 = 50 kJ/mol indicates the presence of the keto and hydroxy acid's function groups on TRGO. Activation energy Ea1 = 28 kJ/mol related with all other groups including the lighter C–H bonds that destructed due to dehydrogenation of the TRGO. Obtained experimental results are useful for further proposing the kinetic model of the mechanism of the most probable reaction of TRGO decomposition. [ABSTRACT FROM AUTHOR]

The pouring of sand casting is accompanied by severe heat conduction, and there is an urgent need to investigate the pyrolysis properties of foundry sand. The main purpose of this study was to investigate the pyrolysis behaviors of resin sand, including precoated sand (PCS), hot box sand (HBS), and warm box sand (WBS), at heating rates of 20 °C/min, 30 °C/min, and 40 °C/min in nitrogen and air atmospheres. The mass loss of the resin sand was monitored continuously with a simultaneous thermal analyzer, and the kinetic parameters of the resin sand were calculated based on the Coats–Redfern method and thermal data. The average mass loss of the resin sand during pyrolysis was 3.03%, which was much smaller than that of the other sands. The volatile release characteristic index of resin sand could not be calculated based on this concept. To solve this issue, the term Tstv/mloss was established, and its value was determined. With increasing heating rates from 20 °C/min to 30 °C/min and from 30 °C/min to 40 °C/min, the mass losses of the resin sand increased by 0.79% and 0.64%, respectively, and the volatile release characteristic indices of the resin sand increased by 3.8 × 10−10 and 1.06 × 10−9, respectively. In addition, the mass losses and volatile release characteristic indices of resin sand in an air atmosphere were greater than those in a nitrogen atmosphere. With increasing heating rate, the activation energy of the resin sand decreased in a nitrogen atmosphere. The findings concerning the thermal decomposition behaviors of resin sand provided a theoretical basis for the pouring step of the sand casting process. [ABSTRACT FROM AUTHOR]

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The preparation of the Ti 2 AlC MAX phase by activated self-propagating high-temperature synthesis from a mixture of elemental powders using the thermokinetic coupling approach is reported. The underlying mechanism in the Ti–Al–C system has been elucidated. Ti 2 C MXene was produced by exfoliation of its MAX counterpart. The combustion wave sensitive parameters were determined, the influence of promoter and ambient gas pressure on the phase composition and evolution of the microstructure was revealed. The Ti 2 AlC MAX phase was successfully prepared in an energy-efficient pathway with some controlled amount of TiC. The interaction mechanism, simulated at comparatively higher heating rates (β = 600–4800 °C·min−1), demonstrated the evolution of the following phases: Ti 3 Al, TiC, Ti 3 AlC, Ti 2 AlC, T 3 AlC 2 , Al 3 Ti. Etching for only 2h in combination with double ultrasonic treatment made it possible to delaminate the nanolayered structure of the parent MAX phase and obtain Ti 2 C MXene. [ABSTRACT FROM AUTHOR]

The impact of COVID-19 has boosted growth in the takeaway and medical industries but has also generated a large amount of plastic waste. Peanut shells (PS) are produced in large quantities and are challenging to recycle in China. Co-pyrolysis of peanut shells (PS) and polypropylene (PP) is an effective method for processing plastic waste and energy mitigation. Thermogravimetric analysis was conducted on PS, PP, and their blends (PS-PP) at different heating rates (10, 20, 30 °C·min−1). The results illustrated that the co-pyrolysis process of PS-PP was divided into two distinct decomposition stages. The first stage (170–400 °C) was predominantly linked to PS decomposition. The second stage (400–520 °C) resulted from the combinations of PS and PP's thermal degradations, with the most contribution from PP degradation. With the increase in heating rate, thermogravimetric hysteresis appeared. Kinetic analysis indicated that the co-pyrolysis process reduced the individual pyrolysis activation energy, especially in the second stage, with a correlation coefficient (R2) generally maintained above 0.95. The multi-level reaction mechanism function model can effectively reveal the co-pyrolysis process mechanism. PS proved to be high-quality biomass for co-pyrolysis with PP, and all mixtures exhibited synergistic effects at a mixing ratio of 1:1 (PS1-PP1). This study accomplished effective waste utilization and optimized energy consumption. It holds significance in determining the interaction mechanism of mixed samples in the co-pyrolysis process. [ABSTRACT FROM AUTHOR]

This study focuses on the energetic valorization of agave bagasse (AB) waste. The pyro-gasification tests with air were conducted in a thermogravimetric analyzer (TGA) coupled with a micro-gas chromatograph (μ-GC) analyzer using AB as feedstocks and α-cellulose (CEL) as biomass model. The effects of heating rate values (10 to 80 °C/min) and stoichiometric air-to-biomass ratio values (ABR) on the performance of the process were investigated. The evolution of CO, CO2, CH4, and H2 was monitored through online and offline TGA/μ-GC measurements. It was shown that CO and CO2 were mainly released at a temperature below 450 °C and followed almost the same pattern. The CH4 started to evolve at a temperature above 300 °C, while the maximum H2 production was obtained between 600 and 700 °C. In addition, an appreciable decrease in the combustible gas composition (CO, CO2, CH4, and H2) was achieved with an increment in ABR, while the fraction of non-combustible gases (CO2 and N2) increased. On the other hand, the increase in heating rate positively influences combustible gas yields. In fact, the H2 production increased from 70.75 to 128.89 mL/(g of feedstock) with the increase in heating rate from 10 to 80 °C/min, thus improving in the process efficiency from 33 to 60. The average lower heating value of the fuel was about 5.5 MJ/Nm3. The results suggest that air pyro-gasification for hydrogen-rich gas production could be a promising route for the energetic valorization of AB waste. [ABSTRACT FROM AUTHOR]

The study of the processes occurring in the temperature range of the main decomposition of the organic mass of coal (OMC) makes it possible to understand both the general patterns and the specifics of the decomposition of solid fuels. This temperature interval is used to calculate the kinetic parameters of the process, which carry important information both about the nature of the structural-chemical transformations and about the structure and direction of thermal destruction of OMC. In this article, to study the kinetics of pyrolysis of coal, the method of thermogravimetric analysis was used, in which heating of coal samples was carried out in ceramic crucibles in the temperature range of 25-900 °C at different heating rates (5-25 deg/min) in nitrogen and oxygen media. Coal from the Kenderlyk deposit was chosen as the object of study. Based on the constructed differential DTG curves (dependence of the sample mass change rate on time) at different heating rates, the kinetic parameters of pyrolysis of coal were calculated using the equations of non-isothermal formal kinetics. The effect of the rate and temperature of coal heating on the kinetic parameters of pyrolysis of coal has been studied. The main stages of OMC decomposition are revealed. It has been found that the heating rate of coal samples significantly affects the temperature and process rate corresponding to the main decomposition maxima on the differential DTG curves. The dependence between the kinetic parameters of pyrolysis of coal in the temperature range of the main decomposition of OMC on the rate and temperature of heating, as well as between the kinetic parameters at different stages of the main decomposition of coal, is analyzed. [ABSTRACT FROM AUTHOR]

This study aimed to dissect the thermal effects and kinetic behaviors of coal spontaneous combustion (CSC) under different heating rates (5, 10, 15, and 20°C/min). The charred coal, nonstick coal, and gas-fat coal were collected as coal samples, and thermogravimetric (TG)-differential scanning calorimeter (DSC) were performed. First, four characteristic temperatures were determined, and the CSC process was divided into four stages. Second, the characteristic temperatures, reaction stages, mass loss and thermal effects were investigated. The results indicated that as the characteristic temperatures increased, mass loss changed little, the TG-DSC curve peak shifted to high temperature, and the total heat release increased as the increases of heating rates. In addition, kinetic parameters of the conversion rate and activation energy was calculated. The apparent activation energies for the collected coal samples found by the Flynn-Wall-Ozawa method were 104.84, 95.51, and 129.84 kJ/mol, respectively, and those found when using the Kissinger method were 86.75, 78.90, and 110.54 kJ/mol, respectively. The results revealed that CSC occurred more difficultly in gas-fat coal than in charred coal. The results can provide theoretical support for the prediction and prevention of CSC in various applications. [ABSTRACT FROM AUTHOR]

Pyrolysis is a thermochemical process of degradation of organic compounds where the reaction takes place in an inert atmosphere. The process scale varies between industrial, semi-industrial or laboratory. During the pyrolysis process temperature has to be controlled, but, most of pyrolysis studies do not clearly state where the temperature is measured and weather the temperature field is uniform. In this paper thermal behavior of a laboratory scale fixed-bed reactor and energy consumption during pyrolysis processes were analyzed. Three different samples were used: mixture of plastic waste (sample 1), biomass (sample 2) and mixture of plastic waste and biomass (sample 3). The analysis of the thermal behavior of the reactor indicates that with careful regulation or temperature control of the process, one can obtain diagrams that can be used for the purpose of recording thermally intensive processes, similar to more complex thermogravimetric (TG) and derivative thermogravimetric (DTG) analyses. It has been shown that it is possible to change the heating rate and the overall energy efficiency of the process by simply choosing the appropriate raw material mixture.

Coal cakes with dimensions of 500 mmx350 mmx400 mm were prepared using pulverized coal,coke powder,and coal pitch as raw materials,adding 10 mass% of water,and stamp charging.When the furnace temperature was 650 °C,the coal cakes were placed in single-side heating furnaces,and heated at different heating rates till forming coke,with final coking temperature of 1 050 °C.The effects of lining materials (clay bricks and silica bricks) and heating rates (0.5,0.6,and 0.7 °C·h-1) on the heating rate of the coal cakes and the properties of the formed coke were studied.The results show that due to the better thermal conductivity of silica bricks compared to clay bricks,the coal cakes in the furnace using the silica brick lining have a shorter water vaporization time,and a higher heating rate in the first shrinkage peak stage between 200-600 °C,which leads to higher internal stress in the coal cakes and a lower coke agglomeration rate.Therefore,when using silica bricks as the wall of coke oven carbonization chambers,the heating rate should be 0.5 °C·h-1,while for clay bricks as the wall,the heating rate should be 0.6 °C·h-1. [ABSTRACT FROM AUTHOR]

Zirconium alloys are widely used in nuclear water reactors as cladding materials. The cladding materials will absorb hydrogen from high temperature water during the operation of nuclear reactor. In cladding tubes, it has been common sense that circumferential hydrides form without stress, while radial hydrides can form when the hydrides are reoriented under stress loading. In this study, we found that a high heating rate can result in hydride reorientation behavior even without stress. At elevated heating rates, the zirconium alloy clad tube developed a non-uniform strain gradient along the direction of heat conduction. Hydrogen atoms migrate preferentially to areas of elevated stress and precipitate as hydrides that are perpendicular to the direction of tensile stress, resulting in the formation of radial hydrides that appear as “sun spots” macroscopically. Additionally, the high heating rate disrupts the {0001}α∥{111}δ, α∥δ orientation relationship between the hydride and the substrate, which potentially facilitates crack propagation.

The glass fiber cloth is a kind of composite material made of graphene and glass fiber. The covering rate of graphene on glass fiber is more than 99 %, so it is an excellent electric heating material. Tn order to study the electrical heating properties of the glass cloth made of montmorillonite and promote its application in related fields, the electrical heating properties of the glass cloth made of montmorillonite with different surface resistance values were tested. The results show that, on the macroscopic level, the monofilament fiber is 7.5/. tm in diameter. The color of the monofilament fiber is uniform and the color difference is not obvious. There are 312 monofilaments in a single tow, the space between square holes is 430.27-438.34/im, and the twist is controlled at about 70 twist. At the micro-level, shown by the scanning electron microscope, the surface of the tow is covered evenly by graphene, not flaky, incomplete or wrinkled, and the surface of the monofilament is smooth and clean while the obvious 2T) and G peaks were observed by Raman spectroscopy. The results show that the lower the surface resistance is, the faster the heating rate is, and the higher the stability of the electric heating temperature is. The electrical heating temperature of 150 fl/1 I graphene-skinned glass fiber cloth can be rapidly stabilized at 543 °C, and the heating rate can reach 185.1 °C/s. For the graphene-skinned glass fiber cloth with large surface resistance, both the temperature stability and the temperature rise rate show a significant downward trend at the same voltage, and the surface resistance of different surface resistance specifications of graphene-skinned glass fiber cloth is negatively correlated with the electric heating temperature. There is a positive correlation between the input voltage and the electric heating temperature. [ABSTRACT FROM AUTHOR]

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