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Polymer-derived SiBCN ceramics with good high-temperature stability and temperature-sensitive properties can be used in real-time temperature monitoring in the aeronautical industry. However, previous investigations mostly focus on the temperature sensitivity of SiBCN ceramics but neglect the fast temperature conversion of the real operating environment and its effect on the temperature sensitivity, which hinders their further practical application. In this study, the response to rapid temperature changes of polymer-derived SiBCN was studied. SiBCN ceramics maintain excellent high-temperature semiconductor performance under rapid heating, and its direct-current (DC) conductivity increases with increasing temperature. The conductive mechanism conforms to the amorphous semiconductor formula, following three different transition mechanisms in different temperature regions. The resistance of SiBCN increases with the number of cycles during 100 cycles of 500–1200 °C, presenting excellent temperature-sensitivity and relatively good sensing stability. This work demonstrates that SiBCN ceramics can maintain excellent temperature-resistance under extreme environments with rapid heating and cooling, and it is hoped that this work could guide the development of temperature sensors for extreme environments in the future. [Display omitted] [ABSTRACT FROM AUTHOR]

Rapid heat treatment is essential in manufacturing advanced high-strength steels. The initial microstructure significantly influences the steel's microstructure and properties after rapid heat treatment. The present study investigated how the initial microstructure affected phase transformation, microstructure, and properties of bainite in high-carbon low-alloy steel during rapid heat treatment. Under rapid heating, ultrafine bainite (UB) sample with homogeneous composition exhibits the lowest austenitization temperature, while globular pearlite (GP) sample with poor composition homogeneity has a higher austenitization temperature. After rapid heat treatment, the compositional distribution of the initial microstructure was partially retained in the final sample. The increase of alloying elements inhibits the nucleation of bainitic ferrite, making it easier for bainitic ferrite to grow at low-alloy positions. Finally, a large amount of retained austenite is obtained in the alloying element-rich area. The difference in microstructure results in samples with different initial microstructures having similar strengths but differing plasticities. In samples with an initial lamellar pearlite (LP) microstructure, there was a substantial amount of thicker, filmy retained austenite, with an average thickness of 96.8 nm. This led to a small increase in Kernel Average Misorientation (KAM) with strain during the tensile process. This improvement in coordinated deformation during straining indicates that the sample has achieved excellent performance, with a tensile strength of 1483 MPa and a uniform elongation of 23 %. When the initial microstructure was GP, the sample contained a large amount of crumbly retained austenite with a low aspect ratio. This structure poorly coordinated deformation with higher strain, resulting in numerous microcracks. [ABSTRACT FROM AUTHOR]

The energy utilization of furfural residue is an effective way for the clean production and carbon emission reduction of the furfural industry. In this study, the co-pyrolysis behaviors and products distribution of furfural residue and long flame coal were investigated via TG-FTIR-GC/MS and infrared fast heating technique. According to the analysis of TG-FTIR-GC/MS, the functional groups of carbonyl, phenolic and alkyl were generated with the co-pyrolysis process. As the temperature rose from 500 to 800 °C, the yield of oil increased from 15.27 to 18.24 wt% before decreasing to 16.64 wt%. With the increase in heating rate, the yield of oil increased first from 18.24 to 20.90 wt% and then decreased to 16.70 wt% at 40 °C/s. RSM was employed to optimize the oil yield and the highest oil content of 21.73 wt% was obtained at 650 °C and 30 °C/s. The analysis of GC-MS shows that elevating the temperature and heating rate decreased the content of ketone, phenol, ether, and furan. In addition, the result of simulated distillation shows that the total content of light fractions of oil is between 71.86 % and 77.16 % at all co-pyrolysis conditions. The evolution of char structure was analyzed by Raman, EPR and BET. The higher temperature and heating rate promoted the deoxidation of char to form carbon-centered radicals and developed pore structures. The findings may yield useful insights into the synergistic mechanism of co-pyrolysis between long flame coal and furfural residue, thereby enhancing our comprehension and facilitating future commercial applications. • Co-pyrolysis synergistic effects of coal and furfural residue were analyzed systematically. • Higher temperatures promoted the cleavage of C-O, C-H and β-O-4 to produce radicals. • Co-pyrolysis enhanced oil yields up to 21.73 wt% with over 70 % light fractions. • Infrared fast heating developed pore structures promoting the deoxidation of char. [ABSTRACT FROM AUTHOR]

YBa2Cu3O7-δ (YBCO) thin films were fabricated rapidly on LaMnO3/MgO/Y2O3/Al2O3/Hastelloy substrate by the self-built induction heating system. The growth rate can be more than 60 nm/s, which is much higher than the traditional Metal Organic Deposition (MOD) method. The effects of heating rate, oxygen partial pressure and growth temperature on the texture and morphology of YBCO films were studied, as well as the analysis of properties. The results of X-Ray Diffraction and Scanning Electron Microscopy demonstrated that rapid heating can effectively reduce the residual of BaCO3 particles. The faster heating rate results in a faster YBCO growth rate, easier c-axis oriented grains growth and denser morphology. Moreover, the growth temperature and atmosphere window of YBCO films were obtained in the rapid heating condition. Meanwhile, the YBCO nucleation and growth models were established. This work realized the rapid crystallization of YBCO films by induction heating system and improved understanding of the nucleation mechanism of YBCO on the flexible metal substrate with buffer layers, which is extremely attractive for the industrialization development of Fluorine Free-MOD superconducting films in the future. [ABSTRACT FROM AUTHOR]

The stability of rock mass after fire is a concern of many engineering projects. In this paper, the effects of open fire and different cooling methods on granites were investigated. The static Brazilian test, dynamic Brazilian test, and P-wave velocity test were carried out to evaluate the mechanical properties and damage evolution behavior. A high-speed camera is employed to monitor the failure process of rock. The microstructures of the treated granites were observed by scanning electron microscope (SEM). The results showed that the fire duration and cooling treatment have a significant effect on the P-wave velocity, static nominal tensile strength, and dynamic nominal tensile strength of granite. These characteristics decrease rapidly during 0 to 10 min, and slowly decrease after 20 min. Compared to the air-cooling treatment, the water-cooling treatment has greater damage to the heated granite. To better understand the results, the rapid heating process of open fire heating was simulated using Abaqus software. The results reveal that there is a thinner compressive stress zone at the bottom of the specimen, and there is a large zone in the middle of the sample with higher tensile stress. The crack extension would be expanded due to high tensile stress, leading to the reduction of the tensile strength of the rock. This paper aims to better predict the degree of damage of rock materials after actual fire, as well as preliminarily explore the effect of the fire exposure duration and fire extinguishing method on the tensile properties of rock. [ABSTRACT FROM AUTHOR]

Thermal error always exists in a machine tool and accounts for a large part of the total error in the machine. Thermal displacement in X-axis on a CNC lathe controlled based on a rapid heating system is presented in this paper. Positive Temperature Coefficient (PTC) heating plates are installed on the X-axis of the machine. A control temperature system is constructed for rapid heating which further helps the thermal displacement to quickly reach stability. The system then continuously maintains stable compensation of the thermal error. The presented rapid heating technique is simpler than the compensation of machine thermal errors by interference in the numerical control system. Results show that the steady state of the thermal displacement in the X-axis can be acquired in a shorter time. In addition, thermal errors in constant and varying working conditions could be significantly reduced above 80% and 60%, respectively, compared to those without using the rapid heating. Therefore, the proposed method has a high potential for application on the CNC lathe machine for improving its precision. [ABSTRACT FROM AUTHOR]

The constant challenges associated with metal oxide semiconductor (MOS) gas sensors, such as high operating temperature, low gas-sensing response, and prolonged recovery time towards NO 2 restrain their practical application. Herein, we put forward a novel thought via utilizing the synergistic interplay between La doping modification and chip rapid heating treatment to solve these drawbacks. Wherein, the 3 at% La-doped SnO 2 nanospheres treated at 200℃ by rapid chip heating (referred to as 3LS-200 NSs) exhibited exceptional performance. At room temperature, these nanospheres demonstrated a highly sensitive response of 3008–20 ppm NO 2 within a rapid response time of 9 seconds. Furthermore, this sensor exhibited a low detection limit of 200 ppb and long-term stability. The oxygen vacancy content of 3LS-200 NSs increased by 10.8 % compared with that prepared by normal heating treatment (3LS-200NH NSs) with slow heating rate. The exceptional gas sensing properties of 3LS-200 NSs towards NO 2 can be primarily attributed to the increase of oxygen vacancies, resulting in a reduced bandgap and the Fermi level shift of 0.07 eV toward the conduction band edge, hence enhancing surface electron transfer capability. This work presents a simple and energy-efficient strategy for commercial NO 2 detection. [Display omitted] • The La-doped SnO 2 hollow nanospheres were synthesized via a facile one-step hydrothermal method and rapid chip heating. • The La doping and rapid chip heating pretreatment contributed to efficient NO 2 detection. • The enhanced NO 2 gas sensing performance was explained by oxygen vacancies modulation and band structure adjustment. [ABSTRACT FROM AUTHOR]

Flash sintering (FS) is an important technique in the field of ceramic sintering. Nevertheless, conventional FS is less attractive for practical applications because of the complex shapes and small sizes of the specimens. In this study, using the novel electric field‐assisted hot pressing (FAHP) technique, we successfully achieved FS during the net‐shape hot pressing (HP) process for the first time. It was found that the 3 mol% yttria‐stabilized zirconia (3YSZ) can be flash sintered at 909°C using a fairly low DC field of 33 V/cm under 30 MPa pressure. The grain sizes of the FAHP‐sintered samples were 20% smaller than that of the HP‐sintered sample. When the current density limit is ≥240 mA/mm2, 3YSZ can be fully densified during the flash events. Careful analysis of the sintering curves suggests that although the carrier type or concentration is changed during flash events, it cannot explain the ultrafast densification. Additionally, we devised a qualitative method to analyze the densification mechanism. The results indicated that the ultrafast densification observed during flash events resulted from the synergistic effects of the rapid heating rate and peak sample temperature. Finally, the atomic force microscopy confirmed the lower grain boundary energy for the FAHP‐sintered samples, which accounts for the smaller grain sizes than the HP‐sintered sample. We believe that the FAHP technique could create new possibilities for theoretical and applied research on field‐assisted sintering techniques. [ABSTRACT FROM AUTHOR]

• A unique experimental apparatus was built to study rapid phase transition. • • HFE-7100 ON data for at high heating rates, 106 K/s, are measured for the 1st time. • • Results are obtained in the intermediate heating rates regime (105 to 106. • K/s). • • Maximum superheating degree of 14 K was obtained for a heating rate of 2.2・106 K/s. • • For slower heating rates, superheating spans 12 K for water and 4 K for HFE-7100. Effective thermal management of electronics is crucial for maintaining their reliability, longevity, and optimal performance. As electronic devices become increasingly compact and powerful, the need to explore new and innovative methods for thermal management becomes ever more critical. Rapid transitions of power lead to temperature spikes (hotspots) of up to 100 K, and thus can dramatically increase the failure occurrence of chips. Power spikes imply that heterogeneous nucleation occurs due to rapid heating, which can vary between 104 – 106 K/s, and hence the coolant is in its metastable region under various degrees of superheating. Gaining ONB data with respect to the heating rate holds significance for diverse applications including nuclear installations, engines, inkjet printers, and laser-based systems. In the present paper, we have refined the definition to a heterogeneous nucleation event due to a rapid heating process, that occurs when the timescale for the wall heating is shorter than the critical bubble's significant growth time. Data pertaining to the dependence of the onset of nucleate boiling (ONB) on the heating rate is presented for the first time. Experiments are performed with HFE-7100 fluid that is rapidly heated using a uniquely designed micro-heater, 122 × 234 μm2 in size. The newly designed and constructed system facilitates precise measurements of fast heating processes. In this study, we conducted a series of experiments spanning heating rates from 104 to ∼106 K/s. This range of heating rates was identified in our previous studies as an intermediate regime for water. The region of intermediate heating rates was previously proved in our research to be challenging to attain, due to the varying stability of the metastable zone; it is primarily attributed to pre-existing nucleation sites. Consequently, this led to a notable gap in the experimental results for water, within this particular region, in the literature. Notably, in the current study, we were able to achieve a maximum superheating degree of 14 K at a heating rate of 2.2·106 K/s. Preheated liquids reach the same superheating degree with different heating rates, depending on the coexistence and spinodal curves. It was found that water and HFE-7100 differ significantly in their metastable zone, and that the first zone, for slower heating rates, spans approximately 12 K for water, but only 4 K for HFE-7100. [ABSTRACT FROM AUTHOR]

A warm stamping process of 1 and 1.2 GPa ultra-high strength steel sheets at comparatively low temperatures using rapid resistance heating was investigated to produce high strength parts. The effects of the heating temperature and rate on mechanical and surface properties of warm-stamped parts were examined. For a rapid heat rate of 100 °C/s around a heating temperature of 300 °C, the hardness of the formed parts increased from that of the as-received sheets, and the hardness for the 1.2 GPa sheet approached that of conventional hot-stamped parts from 22MnB5 steel sheets. The increase in hardness appeared only for rapid heating, and not for slow heating using a furnace. The increase in hardness is due to the transformation of retained austenite into martensite at comparatively low temperatures using rapid resistance heating and cooling. For the comparative low heating temperature, the non-coated sheet hardly oxidised, and the galvannealed sheet having high corrosion resistance did not exhibit the exfoliation of the coating layer, whereas the springback did not improve. [ABSTRACT FROM AUTHOR]

The study is focused on using an image analysis to explain the effects of several cycles of rapid heat treatment on the microstructure of 0.213 wt. % carbon steel. The samples examined are subjected to a diffusional heat treatment followed by several cycles of a rapid heat treatment. The process of the diffusional heat treatment involves heating the samples from an ambient temperature to 850oC in an electric muffle furnace for 56 min and then quenching in running water. In order to improve further the mechanical properties of the heat treated samples, they are subjected to several cycles of rapid heating. Each cycle comprises preheating the furnace to 900oC prior to the samples charging. The treated samples are subjected to a microstructural examination using optical microscopy followed by an image analysis using Image J software. The mechanical properties of the heat treated samples are characterized through ultimate tensile, hardness and impact tests. The results reveal that the grain size decreases from 1.07 µm in the control sample to 0.79 µm in the three-cycle sample and increases to 0.86 µm in the four-cycle one. It is also observed that the two-cycle sample shows the highest ductility (15356.3 N/mm2) and the lowest ultimate strength (833.375 N/mm2). This implies that the two-cycle rapid heat treatment is required for grain refinement in mild carbon steel. [ABSTRACT FROM AUTHOR]

ZBLAN glass is a heavy metal fluoride glass that tends to undergo heavy devitrification, resulting in a crystalline material. It has many applications, including its use as an optical waveguide for fiber‐optic technology. However, when the glass is processed with traditional casting techniques, crystallites form readily that act as scattering centers, which results in large attenuation losses. In this study, it has been experimentally demonstrated that processing ZBLAN rapidly with a heating rate of 25 000 K/min and cooling rate of 4000 K/min yields test samples that are fully amorphous and retain a disordered molecular arrangement characteristic of its molten state. This novel method was developed using a specifically designed equipment named a Rapid Electro‐thermal Processing Device, or "REPD." The REPD applies ohmic heating and thermal conduction to a heat sink to rapidly process the ZBLAN material. The absence of crystallites in the rapidly processed ZBLAN test samples were verified using transmission electron microscopy (TEM) analysis. Applying a theoretical algorithm, the critical cooling rate for yielding fully amorphous ZBLAN glass was determined to be 1081 K/min for a sample volume of 9.4 × 10−8 m3. [ABSTRACT FROM AUTHOR]

Highlights • An atmospheric pressure experiment loop with 5 × 5 bundle containing 3 × 3 heat-generating bundle with heating length of 450 mm as the test part was fabricated. • We visualized void behavior and measured the local void fraction, the time-averaged void fraction and the initial bubble detection time were quantified for the transient boiling behavior when the heat output of the bundle changes rapidly in the order of milliseconds. • The relationship between the transverse flow range of bubbles transiently and the bundle heat output was verified. Abstract Rapid thermal elevation in boiling water reactor (BWR) is an important factor for nuclear safety and there is a need to develop an analysis code for the transient phenomenon and its validation process. To evaluate the thermal property of transient boiling and its uncertainty, corroborative experimental information is crucial. In particular, the lateral propagation behavior of a vapor bubble (void) in the cross-sectional direction of fuel assembly has yet to be determined. This study evaluates the void propagation behavior in a 5 × 5 rod bundle with cross-sectional heat distribution that causes only the 3 × 3 rod bundle to generate heat; assuming rapid heating under atmospheric pressure. In this paper, using the maximum heat output applied to the nine heated rods as a parameter, from the visualization of the void behavior and the measurement of the local void fraction, the heat output conditions under circumstances where lateral propagation of voids occurs and where voids are only localized in the heated region are summarized. We quantified the time difference initially detected and the time-averaged void fraction according to the lateral propagation level. [ABSTRACT FROM AUTHOR]

Slightly graphitization might be incurred on CVD diamond films when suffering instantaneous high temperature thermal shock. In this paper, phase transitions of CVD free-standing diamond films have been studied experimentally at the temperature range of 1500–1800 °C through a plasma rapid heating process. Raman spectra and X-ray photoelectron spectra (XPS) are compared and discussed for the purpose of measuring the percentage of graphitic carbon component in CVD diamond films after heat treatment at different temperatures. An obvious optical degradation took place in both visible and infrared bands with the increased treating temperature. The result indicates that graphitization is dominated along grain boundaries rather than in internal grains. In addition, the nitrogen related absorption peaks were not covered by the enhanced optical absorption background, which was caused by the opaque graphitic carbon formed at high temperature. Nitrogen concentrations have also been evaluated for these graphitized diamond films and there is no evidence to show the movement or aggregation of nitrogen atoms. [ABSTRACT FROM AUTHOR]

Fast charging is a key enabler of mainstream adoption of electric vehicles (EVs). None of today's EVs can withstand fast charging in cold or even cool temperatures due to the risk of lithium plating. Efforts to enable fast charging are hampered by the trade-off nature of a lithium-ion battery: Improving low-temperature fast charging capability usually comes with sacrificing cell durability. Here, we present a controllable cell structure to break this tradeoff and enable lithium plating-free (LPF) fast charging. Further, the LPF cell gives rise to a unified charging practice independent of ambient temperature, offering a platform for the development of battery materials without temperature restrictions. We demonstrate a 9.5 Ah 170 Wh/kg LPF cell that can be charged to 80% state of charge in 15 min even at -50 °C (beyond cell operation limit). Further, the LPF cell sustains 4,500 cycles of 3.5-C charging in 0 °C with <20% capacity loss, which is a 90x boost of life compared with a baseline conventional cell, and equivalent to >12 y and >280,000 miles of EV lifetime under this extreme usage condition, i.e., 3.5-C or 15-min fast charging at freezing temperatures. [ABSTRACT FROM AUTHOR]

In this paper, the effects of heating parameters, including temperature ranging from 900 °C to 1000 °C, heating rates ranging from 2 °C∙s−1 to 100 °C∙s−1, and 120 s soaking on the non-equilibrium microstructure evolution of Ti-6Al-4V alloy were studied. Microstructures after heating were characterized to reveal the mechanism of non-equilibrium phase transformation. Uniaxial tensile tests at room temperature were carried out to evaluate the effects of non-equilibrium microstructure on the mechanical properties. Results show that higher heating rate and lower temperature lead to lower β phase volume fraction and finer β grains. A transition region with element gradient forms in the α p grain near the α p /β phase boundary and transfers into β phase gradually during the heating. Rapid heating could confine the movement of the transition region, and therefore reduce the α→β transition and growth of the β phase. When the Ti-6Al-4V alloy was heated to 1000 °C at a rate of 50 °C/s and then quenched immediately, the tensile strength was improved by 19.5% and reached up to 1263.0 MPa with the elongation only decreasing from 13.6% to 9.6% compared with the initial material. The main strengthening mechanism is that the rapid heating in the single-phase region avoids the rapid growth of the β phase, which leads to fully fine martensite formation after water quenching. [Display omitted] • Rapid heating reduces the element diffusion and leads to the formation of non-equilibrium microstructure. • Higher strength and ductility of Ti-6Al-4V alloy can be achieved after rapid heating in the single β-phase region. • The main strengthening mechanism is that the rapid heating in the single-phase region avoids the rapid growth of the β phase, which leads to fully fine martensite formation after water quenching. [ABSTRACT FROM AUTHOR]

The major objective of the present study is to clarify the effects of rapid heat solutionizing on tensile strength of A6082 aluminum alloy. In the present investigation, grain dimensions and insoluble IMC particle were investigated both in the traditional resistance heating and in the rapidly heating specimens. Furthermore, the effect of rapid heat solutionizing on tensile strength under an identical artificial aging condition was studied pertaining to the observation on the insoluble particles present in the material due to the solidificational process and which undergone rapid heat solutionizing. The critical strain of tensile serrated flow caused by Portevin-Lechatelier (PL) effect was compared with that of the resistance heating specimens. Such rapid heating specimen is also showing larger critical onset strain in the tensile serrated flow (ɛc), suggests that the rapid heating process could offer a higher concentration on solution solutes. Hardness and tensile strength data indicated an increasing aging effect, the higher concentration of Mg and Si solid solution also lead to a shorter limiting T4/T6 process duration of A6082 aluminum alloy. A significantly shorter heat treatment time to achieve peak hardness (HRB73) without deterioration of tensile strength. The concentration of rapid heat solution was investigated using SEM and TEM, and the above results should be related to the attractive interaction between silicon and magnesium solutes since the onset strain of tensile serrated flow increases with the increasing heating rate. [ABSTRACT FROM AUTHOR]

The kinetics of the reverse martensitic transformation in shape memory alloy wires is studied under conditions at which it is restricted neither by the rate of heat transfer nor by mechanical inertia. Two characteristic times for the transformation are identified and estimated. A model provides a universal expression that fits all experimental measurements performed at different temperatures. The kinetic law predicted by the model indicates that interface velocities are governed by viscous resistance and are thus much slower than the shear wave speed, even under very large driving force values. [ABSTRACT FROM AUTHOR]

The results of experimental study of heat transfer and crisis phenomena at pool boiling of liquid nitrogen with different heating conditions on the surface with capillary-porous coating are presented. Porous coatings with different thicknesses (400 and 1390 μm), morphology and high porosity (up to 80%) were obtained using the new plasma spraying technique. It was shown that at steady-state heat release the heat transfer at boiling essentially depends on the thickness and morphology of the coating. The maximum enhancement (∼300%) compared to the smooth heater was detected to coated heater with a thickness of 1390 μm at low heat fluxes. The mechanism of heat transfer enhancement at pool boiling by using the capillary-porous coatings was proposed. Heat transfer hysteresis was detected for the heater with the coating of 400 μm. For the smooth heaters and the heater with 1390 μm coating, the heat transfer coefficients almost coincide with an increase in the heat flux and with its decrease. Data on the effect of coatings with different thicknesses on the critical heat flux (CHF) at boiling under steady-state heat release are presented. It is shown that for the smooth heaters the value of critical heat flux at rapid heating decreases in comparison with steady-state heat release. Capillary-porous coatings have a significant influence on development of the transition process and crisis phenomena at stepwise heat release. There is degeneration of boiling crisis development at rapid heating on the coated surfaces at the heat fluxes below the value of the CHF at steady state heat release. Fast transition to film boiling at stepwise heat release on the coated heaters with different thicknesses is observed at the heat fluxes 2 times higher than the critical heat fluxes, obtained at steady state heating. [ABSTRACT FROM AUTHOR]

Polycrystalline CVD free-standing diamond films have been heat treated through a rapid heating process using a direct current (DC) arc plasma jet system within the temperature range of 1500–2000 °C. The optical transmission of the diamond film decreases when the treatment temperature exceeds 1500 °C. When the diamond film was annealed to 1800 °C for just 1 min, the infrared (IR) transmittance at λ = 10.6 μm of the film was significantly decreased from 60.5% to 4.0%, due to the transformation from diamond to graphite. Further increase of the temperature to 2000 °C leads to complete loss of optical transmittance in only 30 s, due to the detrimental occurrence of graphitization. XRD patterns indicate that graphite ultimately grows preferentially along the (0002) plane by forming disordered or turbostratic graphite as intermediate product. Raman spectra and SEM images verify that at 1500–1850 °C graphitic carbon transforms from the diamond surface in the form of protruding submicron crystallites, which were still containing a number of sp 3 C C bonds. In addition to graphitization on the external surface, the diamond-graphite phase transition also occurs along the grain boundaries and the calculated activation energy of the grain boundary graphitization process is 276 kJ·mol − 1 for the CVD diamond. [ABSTRACT FROM AUTHOR]

This study investigates local out-of-plane deformation of a carbon fiber reinforced phenolic polymer ablator subjected to very rapid heating. Local out-of-plane deformation was measured using a three-dimensional digital image correlation technique at high temperatures. This was achieved by attaching high temperature resistant random patterns on the specimen surface using a ceramic bond. Additionally, blue filters intended for cutting strong infrared radiation from the specimen were also used. This study then discusses the mechanisms of the local out-of-plane deformation under rapid heating conditions in terms of carbonization, pyrolysis gas occurrence, gas pressure storage, and interlaminar debonding due to gas pressure. [ABSTRACT FROM PUBLISHER]

A finite element formulation based on a higher-order layerwise theory is presented for the first time to investigate thermally induced vibrations of functionally graded material (FGM) sandwich plates and shell panels. The properties of FGM sandwich are assumed to be position and temperature dependent. The upper and lower layers of the sandwich panel are considered to be made of pure ceramic and metal, respectively and the elastic properties of FGM core are varied according to a power-law function. The top surface is exposed to a thermal shock and the bottom surface of the panel is either kept at a reference temperature or thermally insulated. The one-dimensional transient heat conduction equation is solved using a central difference scheme in conjunction with the Crank-Nicolson method. A higher-order layerwise theory is used for FGM sandwich panels, in which a higher-order displacement field for the FGM core and a first-order displacement field for the facesheets are assumed. The governing equations are solved using Newmark average acceleration method. It is shown that the proposed layerwise finite element formulation is simple and can easily be applied to investigate FGM sandwich plates and shell panels subjected to rapid heating. [ABSTRACT FROM AUTHOR]

• Breakup time of droplets is evaluated as the sum of heating and bubble growth times. • Heterogeneous nucleation temperature depends on the heating rate and is often lower than the homogeneous nucleation temperature. • Smaller droplets lead to both shorter heating and bubble growth times. • Higher ambient temperature lead to longer heating times yet shorter bubble growth times. • Heating time is dominant over the bubble growth duration throughout the entire domain, under conductive or natural convection conditions. • For micron-sized droplets, puffing and micro-explosions are prone to occur during the inertial bubble growth regime. Heating of droplets composed of water and fuel is known to lead to internal nucleation and bubble growth that can eventually lead to their puffing and to micro-explosions. The time to puffing/micro-explosions includes times spent on: heating (time to nucleation P l e a s e s t r i k e t h e S y m b o l t _ N f r o m t h e a b s t r a c t), bubble growth P l e a s e s t r i k e : t gr f r o m t h e a b s t r a c t. In the present paper, we examine the effect of different aspects of bubble growth on the puffing and micro-explosions. Specifically, we address the effects of nucleation temperature and the relative positions of the inner water sub-droplet and the bubble within it. The nucleation temperature of the water sub-droplet is higher than its normal boiling temperature yet lower than its spinodal temperature in most realistic cases. The degree of superheating and the nucleation time depend on the heating rate and the nucleation site density. Higher nucleation temperatures imply larger driving force for the bubble growth. Bubble growth rate is dominated by the degree of superheating, while growth time is dominated by both the degree of superheating and the location of the bubble with respect to the inner and outer interfaces of the composite droplet. It is found that the inertial bubble growth regime is dominant for micron-sized droplets, and thus sensitivity to the modelling of the inertial regime can be of crucial importance to the evaluation of the breakup time for the droplets. The model for puffing and micro-explosion presented in the paper considers an isolated bubble growing at the water/fuel interface at various degrees of superheating, and for a wide range of Jakob numbers. This analysis allows us to assess the sensitivity of bubble growth time to the initial bubble location, and to generalise the previously developed model of the phenomenon taking into account the effect of finite time of bubble growth during the development of puffing/micro-explosion. [ABSTRACT FROM AUTHOR]

The effect of laser annealing on the mechanical properties of severely deformed low alloy steel is discussed. Two different sets of annealing parameters were used to achieve improvements in formability. The resulting microstructures, tensile properties and hardness distributions are reviewed. Annealing at temperatures around 700 °C with very high heating and cooling rates leads to recrystallization at the surface and moderate grain growth in subsequent layers. The improvement in ductility is proven to be sufficient to prevent cracking during bending operations. [ABSTRACT FROM AUTHOR]

A novel dual-phase microstructure (α′ + β) has been prepared in Ti-6Al-4V alloy, which breaks the trade-off effect between strength and plasticity during the traditional solution treatment. This result is attributed to the rapid heating-induced massive-like transformation (α + β → β m) via electropulsing treatment and following martensitic transformation (β m → α′ + β) by water quenching. It was found that there was almost no alloy elements diffusion during the whole transition. Therefore, different from the traditional solution treatment product of V-supersaturated α′, the Al-enriched α′ and remained β were obtained. [Display omitted] [ABSTRACT FROM AUTHOR]

The main aim of the present research was to obtain an optimized microstructure with adequate mechanical properties in a low carbon steel. The effect of microstructure on kinetics of austenite transformation was simulated. A 3.2 mm hot rolled steel was subjected to continuous annealing to obtain properties of Dual Phase 590 grade. Kinetics of austenite transformation was studied with respect to the condition of just pearlite dissolution to form austenite under rapid heating. Annealing parameters were based on process conditions of dual phase steel production in a continuous annealing line. DICTRA was used to simulate heating rates of the order 10–500 °C/s with peak temperatures in the range 750–850 °C to predict isothermal annealing time required for complete dissolution of pearlite into austenite under different temperature-heating rate conditions. Simulation results showed dependency of temperature and heating rate on austenite transformation time. Interestingly, no significant effect of heating rate on complete pearlite dissolution into austenite was evident. Results were validated with limited experimentation on Gleeble. Microstructure analysis validated the simulation results to be accurate. The observations have pertinent inputs while designing industrial continuous annealing line parameters where rapid heating rates are generally encountered (10–20 °C/s). [ABSTRACT FROM AUTHOR]

Silicone rubber sheet heater-aided vacuum-assisted resin infusion molding was developed in order to shorten curing cycle time. Three kinds of cooling methods, including air cooling, air water cooling, and water cooling, were employed; the effects of cooling process on processing time, residual strains, and mechanical properties were experimentally studied. The residual strains generated in cooling stage were monitored by embedded strain gauges. The results showed that in order to avoid serious residual strains and lower mechanical properties, the cooling rate of the silicone rubber sheet heater-aided vacuum-assisted resin infusion molding process should be designed carefully. Slow cooling rate before glass transition temperature of the composites and rapid cooling rate after it might be a practical method to maintain both high processing efficiency and acceptable mechanical properties. [ABSTRACT FROM AUTHOR]

A novel method for ultrashort capillary column gas chromatography (GC) analysis is introduced, which employs on-column injection and detection and rapid temperature programming. Using 10-20 cm long capillary columns, results showed that the method provides efficient and very rapid separations for relatively simple mixtures. Moreover, the on-column aspect of the method used here is demonstrated to avoid the extra column analyte degradation that can occur in traditional approaches to such separations. As a result, the developed method allows for the first time the GC analysis of some very large and (or) highly thermally labile analytes, such as polypeptides and drug molecules that are normally prone to decomposition. As an application, this method is further used to monitor pharmaceutical degradant formation as a function of temperature and was found to provide similar results to those obtained from conventional high-performance liquid chromatography analysis. Overall, the findings indicate that this ultrashort GC column approach could be useful in these areas and potentially others, where relatively simple GC analysis and universal flame ionization detection is desirable. [ABSTRACT FROM AUTHOR]

By combining the synthesis at a higher temperature with the addition of seed, ultrafast synthesis of silicalite-1, a pure-silica zeolite with MFI structure, has been achieved in a tubular reactor that can enable a rapid heating. The synthesis period of silicalite-1 has been shortened to 10 min, while it usually takes several hours or days using the conventional methods. Estimated from crystal size, the apparent crystal growth rate of silicalite-1 was on the order of 10 3 nm/h for the synthesis using TEOS as a silica source, while under another synthesis condition using colloidal silica as a silica source, the apparent crystal growth rate could be as high as 10 4 nm/h. High crystal growth rates demonstrated that the crystallization of silicalite-1 in the tubular reactor could be very fast. [ABSTRACT FROM AUTHOR]

Industrial gasifiers and combustors are assumed to reach particle heating rates of 10 5 –10 6 °C/s and understanding how particles behave in these extreme conditions can improve the utilization of solid fuels in these reactors and in downstream applications. By studying intermediate devolatilization processes during solid fuel pyrolysis, detailed models for solid fuel conversion can be formulated. Key objectives of this study included (1) investigate possible mechanisms that promote the formation of synthesis gas components and char, (2) compare the devolatilization behavior of pyrolysis by varying particle size, hold time, and temperature and (3) correlate char deactivation with hold time. The objectives of the study were accomplished using a wire-mesh reactor with a uniform heating rate of 500 °C/s in nitrogen under atmospheric pressure. A design of experiments approach was used to quantify the effects that hold time, temperature, and particle size had on char yield, evolved gas composition, and apparent activation energy of pine stem wood and wheat straw. Key results indicate that with increased temperature and hold time more volatiles evolve from the fuels and favor carbon monoxide and methane production at higher temperatures. Apparent activation energy of the volatile matter decreases with hold time. An abbreviated model for apparent activation energy correlates well with experimental data and assumes that along a devolatilization pathway, that not all volatiles are driven from the fuel. [ABSTRACT FROM AUTHOR]

In this study, a working coil coupled with magnetic flux concentrators for barrel induction heating in an injection molding machine was investigated. Induction heating process simulations were developed to evaluate the effects of magnetic flux concentrators to the temperature distribution at surface inside a barrel of an injection molding machine. Different pitches of magnetic flux concentrators were applied to study the uniform heating capability of induction heating system with heating coil coupled with magnetic flux concentrators via commercial software, ANSYS. Models of working coils coupled with magnetic flux concentrators were experimented to verify the simulation results. The results from simulation and experiment agreed well. Simulation results showed that, changing diameters of a barrel or varying operation frequency of induction power supply had no effect on uniform temperature distribution at the inside surface of the barrel. [ABSTRACT FROM AUTHOR]

The formation of ZrB 2 through reaction of ZrO 2 with B 4 C without adding carbon has been studied at different temperatures between 1020 °C and 1600 °C. The ratio of ZrO 2 /B 4 C was optimized to produce a single phase ZrB 2 . By introducing Si species into reaction mixture, composite powders of ZrB 2 –SiC, ZrB 2 –SiC–B 4 C are produced. The SiC in composite powder was well distributed in ZrB 2 matrix and the powder was successfully air plasma coated on to CC composite. To scale up the process in a continuous furnace, the reactant mixture of (ZrO 2 +B 4 C+Si) was rapidly heated by suddenly introducing the reactant compact in to an air furnace held at different temperatures between 900 °C and 1700 °C. The extent of reaction after short duration of 3–5 min has been studied. The formation of ZrB 2 and SiC was confirmed through XRD and SEM analyses in samples reacted at and above a temperature of 1300 °C. Though coarsening due to agglomeration was observed with increase in reaction temperature from 1300 °C to 1700 °C, sub-micron sized particles were seen existing even after reaction at 1700 °C. A possible furnace design for continuous operation has been proposed. [ABSTRACT FROM AUTHOR]

Concerning the emissions of hydrogen cyanide (HCN) and other N-bearing air pollutants from the fluid catalytic cracking (FCC) regeneration units, this paper has conducted a comprehensive testing and surface characterisation of four industrial spent catalysts, aged catalysts and hard coke sample in three different schemes, Ar-TPD, O 2 -TPO and rapid heating to elaborate the transformation of N upon the influence of the heterogeneity of coke and N speciation. In the Ar-TPD scheme, the surface N is responsive for the emission of gaseous NH 3 from pyrrolic N-5 and HCN from both pyridinic N-6 and quaternary N-Q. The removal of soft coke is beneficial in promoting the surface exposure of hard coke, thereby increasing the HCN emission dramatically. In the O 2 -TPO scheme, the oxygen accessibility is the principal factor governing the emission of HCN. The external soft coke is able to access the bulk O 2 firstly, the combustion of which in turn provides heat back to promote the cracking of internal hard coke from the same and neighbouring particles to release more HCN. The induction effect of bulk O 2 is also superior over the spent catalyst properties in formulating a nearly identical trend of HCN emission for all the four spent catalysts tested. Finally, for the use of rapid heating scheme that is typical in a commercial FCC regenerator, it is effective in accelerating the volatilisation of soft coke quickly, thereby promoting the oxygen accessibility to hard coke and the internal N-bearing precursors so as to mitigate the emission of HCN effectively. The use of a large superficial velocity of gas is further effective in sweeping the volatiles including HCN away from the catalyst, promoting their oxidation extent accordingly. [Display omitted] • Surface pyridinic and quaternary N are responsive for the emission of HCN in TPD. • Progressive oxidation of surface coke promotes HCN out from internal coke. • Both intra- and inter-particle interaction occur between the soft and hard coke. • Rapid heating promotes the volatilisation of coke and oxygen accessibility to N. • Emission of HCN is the least in the rapid heating and oxidation scheme. [ABSTRACT FROM AUTHOR]

The vibration and transient response of rapid heating on inner surface of the functionally graded material (FGM) circular cylindrical shells with outer magnetostrictive layer is investigated and computed by using the generalized differential quadrature (GDQ) method. The effects of heat flux value, power law index value, environmental temperature value and control gain value on Terfenol-D FGM circular cylindrical shell subjected to two edges clamped condition due to the not very high temperature fluid rapidly flow into the circular cylindrical shells from one side to the end of axial length direction are analyzed. The higher amplitudes of displacement and thermal stress can be obtained under the higher rapid heat flux value. With suitable product of coil constant and control gain value can reduce the amplitudes of displacement and thermal stress into a smaller value. The displacement of Terfenol-D FGM circular cylindrical shell versus the Terfenol-D thickness is stable for all power law index values. The Terfenol-D FGM circular cylindrical shell can stand against the higher temperature of environment with some values of power law index under rapid heating. [ABSTRACT FROM AUTHOR]

Abstract: Ti–43Al–5V–4Nb (at%) intermetallic compounds were fabricated by a rapid heating and open die forging method using blended elemental powders. The process route consisted of powder blending, compacting, rapid heating, open die forging and heat treatment. During heating there is porosity in the blended and warm compacted powder billets which still persists after the first forging. In order to remove this difficulty a two stage forging process was used. A fully lamellar structure was seen in the TiAl alloy after heat treatment. Overall, the TiAl alloy showed moderately good mechanical properties at room temperature and good mechanical properties, with reasonable strength and good ductility at high temperatures. [Copyright &y& Elsevier]

Abstract: In this study we investigate the role of gas phase oxygen on ignition of nanothermite reactions. By separately evaluating the temperature at which ten oxidizers release gas phase species, and the temperature of ignition in an aluminum based thermite, we found that ignition occurred prior to, after or simultaneous to the release of gas phase oxygen depending on the oxidizer. For some nanothermites formulations, we indeed saw a correlation of oxygen release and ignition temperatures. However, when combined with in situ high heating stage microscopy indicating reaction in the absence of O2, we conclude that the presence of free molecular oxygen cannot be a prerequisite to initiation for many other nanothermites. This implies that for some systems initiation likely results from direct interfacial contact between fuel and oxidizer, leading to condensed state mobility of reactive species. Initiation of these nanothermite reactions is postulated to occur via reactive sintering, where sintering of the particles can commence at the Tammann temperature which is half the melting temperature of the oxidizers. These results do not imply that gas phase oxygen is unimportant when full combustion commences. [Copyright &y& Elsevier]

The rapid heating effects on the microstructure, texture and magnetic properties of 3% Si non-oriented electrical steel has been investigated through optical microscopy, X-ray diffraction and Epstein frame. The results show that recrystallized grains were refined with increased heating rate, caused by the nucleation rate increase, which is faster than the growth rate due to rapid hearting. With the heating rate increase, the characteristic {111} recrystallization fibre of cold-rolled steel was depressed, but the beneficial 〈001〉//RD and 〈001〉//ND fibres were significantly strengthened. Although the grain-size decreases with heating rate increasing, the optimal magnetic properties can also be obtained through the recrystallized grain-size and texture optimization by rapid heating. In this research, we find the magnetic properties optimization can be obtained when annealed with 100°C/s heating rate: the core loss ( P) decrease 13% and the magnetic induction ( B) increase 3%. [ABSTRACT FROM AUTHOR]

Shape memory alloy (SMA) actuators are very promising due to their large strain and work-output, but are considered to be very slow due to their cooling rate. In this article, we explore the capabilities of a fast one-directional actuation mode based on one-occasional rapid Joule heating of SMA elements. For this purpose, a unique experimental system has been developed that applies a high-voltage electric pulse to a detwined NiTi wire and measures the resulting displacement due to the martensite to austenite phase transformation. The electric pulse is tuned to produce variable temperature jump of up to 160°C within a risetime of few microseconds. One end of the wire is clamped while the displacement of the other end is monitored both by a laser doppler vibrometer and by an optical encoder that measures the displacement of a grating device. Analysis of experimental results reveals a dead time delay between the electric pulse and the wire’s response, which is attributed to the austenite nucleation time and which determines the limit on the fastest possible shape memory actuation. Further analysis reveals relations between the dead weight used and the average acceleration and maximal velocity obtained. In particular, the maximal velocity correlates to a constant kinetic energy delivered by the wire, which suggests a constant integrand over the stress-strain curve regardless of the dead-weight used. A comparison of actuation performances demonstrates that our actuation experiments are significantly advantageous over other fast actuation methods in almost every actuation aspect reviewed. This demonstrates the great potential of SMA for applications that require high speeds and large displacements one-occasional actuation. [ABSTRACT FROM AUTHOR]

Abstract: Rapid heat cycle molding (RHCM) is a molding process that the mold cavity is rapidly heated to a high temperature before plastic melt injection, and then cooled quickly once the cavity is completely filled. Heating/cooling efficiency and temperature uniformity of the RHCM system are two key technical parameters to ensure a high productivity and high-quality products. In this study, a numerical model to analyze the heat transfer in heating and cooling phases of RHCM was built. The effect of heating/cooling medium, layout and structure of the heating/cooling channels, mold structure, etc., on heating/cooling efficiency and temperature uniformity was studied and discussed by analyzing the thermal responses of the molding system in RHCM process. Based on the simulation results, the optimization design of the RHCM mold with hot-fluid heating was performed. Then, a new RHCM mold structure with a floating mold cavity was proposed to improve the heating/cooling efficiency and temperature uniformity. The effectiveness of this new mold structure was also verified by numerical experiments. At last, a RHCM production line with steam heating and water cooling was constructed for a thin-wall plastic part. In testing production, the molding systems can be heated and cooled rapidly with a molding cycle time of about 72s. The production results show that the aesthetics of the molded parts was greatly enhanced and the weld mark on the plastic part’s surface was completely eliminated. [Copyright &y& Elsevier]

This paper proposes a new induction heating technology capable of controlling a precise exothermic distribution, which is termed zone-control induction heating (ZCIH). The ZCIH system consists of two or more sets of a high-frequency inverter unit and a work coil. The inverter units control the phase angle of the coil current to be in phase with each other. The ZCIH has the capability of operation with the mutual inductance, and enables locating the coils as close as possible. As a result, the ZCIH technology makes it possible to achieve rapid heating performance with extremely precise exothermic distribution. This paper presents experimental results of a 150-kW six-zone ZCIH system for semiconductor heat processing. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 171(1): 37–45, 2010; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/eej.20908 [ABSTRACT FROM AUTHOR]

Abstract: In metallic glasses, the presence of the glass-to-liquid transition upon heating is a measure for evaluating thermal or structural stability against crystallization. In some less-stable metallic glasses, the crystallization precedes the glass transition, while the distinct glass transition is observed prior to crystallization for some stable metallic glasses. This feature seems to be exceptional for metallic glasses and rarely observed for other kinds of glass materials, e.g., covalently bonded glasses. In this paper, focusing on this intriguing feature of metallic glasses, we investigate the glass-to-liquid transition of Zr70 Ni30, Zr70 Cu30, and Pd42.5 Ni7.5 Cu30 P20 (numbers indicate at.%) metallic glasses for varying the heating rate in differential scanning calorimetry. Although in Zr70 Ni30 metallic glass, the glass-to-liquid transition is not detected for ordinary heating rates, sufficiently rapid heating exposes the glass-to-liquid transition by suppressing crystallization. Whereas two fitted curves for glass transition temperature, and crystallization temperature, against intersect at a quite small for Pd42.5 Ni7.5 Cu30 P20, their intersection occurs at a relatively large for Zr70 Cu30 or Zr70 Ni30. The value of at the intersection apparently reflects the thermal stability of metallic glasses. [Copyright &y& Elsevier]

Thermal cycling of molds is frequently desired in thermoplastic processing. Thermal cycling of the entire mold with a large mass, however, requires an exceedingly long cycle time. A processing strategy for mold rapid heating and cooling, involving a thin-shell mold and two thermal stations (one hot and one cold), was investigated. Because of its low thermal mass, the shell mold can be rapidly heated amid! cooled through heat conduction by selectively contacting with the two stations. Numerical simulations were performed to study the effect of different design parameters, including thermal contact resistance, shell material, and shell thickness, on the thermal response at the mold surface. Experimental studies showed aluminum shell molds with a thickness of 1.4 mm can be rapidly heated from room temperature to 200°C in about 3 s using a hot station at 250°C. The method was used for thermal cycling of embossing tools. Surface microfeatures can be rapidly transferred from thin metallic stamps to polymer substrates with cycle times less than 10 s. [ABSTRACT FROM AUTHOR]

Abstract: The dynamics of boiling succeeding spontaneous nucleation on a small film heater immersed in ethyl alcohol are investigated at heating rates ranging from 107 K/s to approximately 109 K/s, under which spontaneous nucleation is dominant for the inception of boiling. Immediately after the concurrent generation of a large number of fine bubbles, a vapor film that covers the entire surface is formed by coalescence and rapidly expands to a single bubble. As the heating rate is increased, the coalesced bubble flattens and only a thin vapor film grows before cavitation collapse. Similar behaviors are also observed for water. Based on the observed results, a theoretical model of the dynamic bubble growth due to the self-evaporation of the superheated liquid layer, which develops before boiling incipience, is presented. The calculated results are compared with the observed results. [Copyright &y& Elsevier]

Abstract: Bulk face-centered-cubic (fcc)-based η-MoC1− x and hexagonal-close-packed (hcp)-based β-Mo2C have been prepared using C3H8/H2 by temperature-programmed reaction method and a rapid heating method. In this work, direct carburization of MoO3 produces η-MoC1− x or MoO x C y with excess carbon, different from that with CH4/H2 or C2H6/H2 as carburization reagent. A successive post-treatment by hydrogen causes the phase transformation from fcc-based η-MoC1− x or MoO x C y to hcp-based β-Mo2C. Amorphous SiO2-supported β-Mo2C is also successfully prepared by the two methods and passes through the same route as the bulk one. HRTEM, BET surface area measurements and thiophene hydrodesulfurization reaction are conducted for the comparison of the two methods. The results indicate that different ramping rates bring slight difference in specific surface area and initial catalytic activity but obvious difference in particle size to the final product supported β-Mo2C. [Copyright &y& Elsevier]

Abstract: Rapid heating of a liquid by a thin film heater surface may initiate homogeneous nucleation of vapor in the liquid in contact with the surface. In such circumstances, nucleation is generally expected to be most likely in the hottest liquid closest to the surface. It is known, however, that in many cases the liquid molecules closest to the surface will experience long-range attractive forces to molecules in the solid, with the result that the equation of state for the liquid near the surface will differ from that for the bulk liquid. In the investigation summarized here, a statistical thermodynamics analysis was used to derive a modified version of the Redlich–Kwong fluid property model that accounts for attractive forces between the solid surface molecules and liquid molecules in the near-wall region. In this model, the wall–fluid attractive forces are quantified in terms of Hamaker constants. This feature makes it possible to assess the effect of wall–fluid force interactions on the spinodal conditions for a variety of fluid and surface material combinations. The variation of pressure near the wall predicted by this model agrees well with the predictions of a hydrostatic model and molecular dynamics simulations. The results of the thermodynamic model analysis indicate that force interactions are important for a wide variety of fluids only within a few nanometers of the solid surface. The model specifically predicts that these forces increase the spinodal temperature in the near-surface region. The implications of this increase for nucleation near a solid surface during rapid heating are explored for circumstances similar to those in inkjet printer heads. The results of the analysis imply that during rapid transient heating, wall effects can result in homogeneous nucleation occurring first at a location slightly away from the solid surface. The results further suggest that on rough surfaces, wall effects may play a role in making some cavities preferred sites for homogeneous nucleation. [Copyright &y& Elsevier]

Abstract: We report on the crystallization of silicon films by the joule heating method using Cr strip heater. We report on the lateral crystalline grain growth of silicon thin films by induced holes fabricated in Cr strip. A temperature gradient is generated by the holes, which causes lateral crystalline grain growth. The duration of the electrical current flow in the Cr strip heater is 5 μs. The crystallization experiment is evaluated by Raman scattering spectra in particular by analyzing the sharp crystalline TO phonon peak around 517 cm−1. [Copyright &y& Elsevier]

In this paper, we studied characteristic behavior of Pt48.75Pd9.75Cu19.5P22 metallic glass during rapid heating. We first rapidly heated a cylindrical specimen of 2 mm in diameter and 5 mm in height by induction heating at a rate of up to 100 K/s. During the heating, glass transition temperature Tg and the crystallization temperature Tx increase with increasing heating rate. The material exhibits a Newtonian viscous flow in the supercooled liquid temperature range, and the normal viscosity decreases with increasing heating rate. The normal viscosity is 2×103 Pa s at a heating rate of 100 K/s. We developed a new microforming system as an application of this phenomenon. The system consists of a rapid resistance-heating unit for foil specimens, a glass transition detector, a linear actuator for driving a tool, and the associated control circuits. With this apparatus, we transferred a three-dimensional micro-shape to the materials within 30 s. A conventional superplastic forging system requires a long time to heat work specimens and to deform them. The developed system thus facilitates mass production of micro parts for micro electro mechanical systems (MEMS). [Copyright &y& Elsevier]

Time profiles of weight change of coal samples and the evolution of low molecular weight gases (H2, CH4, CO and CO2) in both steam gasification and pyrolysis of Yallourn brown coal and Taiheiyo subbituminous coal were measured using a thermobalance reactor with a micro GC and a mass spectrometer, in order to examine the reaction mechanism of steam gasification with rapid heating (100 K s−1). It was found that, in the case of slow heating, steam reacted with metaplast and promoted the evolution of tar above 623 K and that a water shift reaction took place above 873 K. Steam gasification of produced char occurred above 1023 K, increasing the evolution of CO, CO2 and H2. When the heating rate was high, steam reforming of volatile matter and steam gasification of metaplast took place parallel to metaplast formation and condensation. The char produced by pyrolysis was almost completely gasified and converted into H2 and CO2 by steam. The chemical energy of coal was mainly converted into hydrogen energy and the gasification efficiency was slightly increased by rapid heating (i.e. 100 K s−1). [Copyright &y& Elsevier]

Measurements of the bulk magnetic properties for two non-oriented electrical steels after a rapid heating are reported. A deterioration of the magnetic properties was observed for the fully processed non-oriented grade and an improvement for the semi-processed non-oriented grade. This publication emphasizes the effects due to the competition between the increase of the grain size and the appearance of thermal stresses during the rapid heating on the magnetic properties of the steels. [Copyright &y& Elsevier]

The response of inertinite-rich Witbank coals (South Africa) to rapid heating was evaluated using petrography, selected Nuclear Magnetic Resonance (NMR) and X-Ray Diffraction (XRD) structural parameters. A total of thirteen (13) coal samples were collected from the No. 2 Seam; a set of six (6) samples from the western and the eastern sides of a ~ 0.4 m thick dolerite dyke emplaced into the coal seam at 0.25 m intervals. An unaltered coal (Un-C; the 13th sample), collected away from the dyke but within the same seam at the mine, was included for comparison. All 13 coal samples were dominated by inertinite. Semifusinite was most abundant in the samples from the western side of the dyke, whereas the proportion of inertodetrinite was highest in samples from the eastern side. Due to very low vitrinite contents, mean random total reflectance (%RoTmr) was used to compare the maturity of the inertinite-rich coals. A decrease in volatile matter was correlated with an increase in mean random total reflectance (%RoTmr; measured on semifusinite, inertodetrinite, and vitrinite), the latter used as a potential maturity indicator for the thermally altered inertinite-rich coals. Mean random total reflectance rose from a background value of 1.52%RoTmr (for Un-C) to 2.83%RoTmr for the coal sample at the western coal-dyke contact (0.0 m). The corresponding reflectance values for the thermally altered coals from the eastern side were less consistent, decreasing closest to the dyke (1.93%RoTmr for the sample at 0.0 m); this trend is also reflected in the NMR and XRD parameters. Eight (8) samples were selected for the NMR analysis, representative of the maceral composition and maturities of the coals investigated. For Un-C, the fraction of aromatic carbons (fa) was 0.88 (average number of carbons per aromatic cluster (C) = 17), and the interplanar spacing (d002) was 3.48 Å (with a crystallite height of 22.09 Å). For the thermally altered coals from the western side, fa decreased from 0.96 at the coal-dyke contact (C = 26 for sample at 0.0 m) to 0.92 for the sample at 1.25 m from the dyke (C = 20). For samples from the eastern side, fa increased from 0.91 (C = 19 for the sample at 0.25 m) to 0.93 (C = 23 for sample at 0.5 m), before decreasing to 0.89 further from the dyke (C = 18 for sample at 1.25 m). In general, the d002 values for the thermally altered coal samples were larger than for graphite. Similarly, only marginal increases in crystallite heights were observed. Although the dyke induced coal maturation and the resultant increase in fa , the overall lack of graphitic order in the thermally altered coals was ascribed to the limited thermal energy provided by the relatively thin dyke; increased heat input would be required to effect significant structural changes in the inertinite-rich coals. Differences between the two sets of thermally altered coal samples were attributed to the emplacement dynamics of the igneous intrusion, which require further investigation. [ABSTRACT FROM AUTHOR]