Core Heating Research Articles

Nanosecond Pulsed Laser‐Heated Nanocrystals Inside a Metal‐Organic Framework Matrix

AbstractInvestigations on gold and gold‐zinc oxide nanocrystals encapsulated in a matrix of a metal‐organic framework (ZIF‐8) upon plasmonic heating with nanosecond laser pulses are presented. Irradiation of Au@ZIF‐8 composite particles leads to heating of the gold core and decomposition of surrounding matrix acting as temperature probe. Cavities inside the ZIF‐8 matrix are found on TEM images after irradiation. Their size is determined dependent on laser energy density and the generated heat at the gold core after absorption of a laser pulse approximated. The surrounding of the gold cores can be heated up to ZIF‐8 decomposition over a distance up to 60 nm. This represents a method to visualize heat transfer from the gold cores to the ZIF‐8 matrix in three dimensions. Studies on ZIF‐8 encapsulated Au@ZnO dot‐rod particles give insight in heat transfer between the particle components and show the applicability of the method to different, more complex systems.

Molecular Dynamics Study of Melting Behavior of Planar Stacked Ti–Al Core–Shell Nanoparticles

Selective laser sintering (SLS) is one of the most commonly used methods in additive manufacturing, due to its high prototyping speed and applicability to various materials. In the present work, molecular dynamics (MD) simulations were performed to study the thermodynamic behaviors of the planar stacked nanoparticles (NPs) model and explore the potential capability of the SLS process with nano-sized metal powders in the zero-gravity space environment. A multi-particle model of titanium–aluminum (Ti–Al) core–shell NP with a particle radius of 50 Å was constructed to investigate the characteristics of the melted pattern during sintering. Two patterns with different spatial densities were considered to study the influence of particle stacking on the melting process. Various core volume fractions and heating rates were examined to investigate their effects on the quality of the final sintered product. The stacked-NPs models with core volume fractions (CVFs) of 3%, 12%, and 30% were linearly heated up to 1100 K from room temperature (298 K) with heating rates of 0.04, 0.2, 0.5, and 1.0 K ps−1. The initial fusion temperature and final sintering temperature for each stacking pattern were obtained via the validation from the radial distribution function, mean squared displacement, and the radius of the gyration analysis. The 30% CVF yields the largest neck size before the melting point, while beyond the melting point, a larger core helps delay the formation of the fully-melted products. It is observed that using the close-packed stacked-NPs model under a slow heating rate (long melting duration) would help form a stable, completely sintered product with a relatively low final sintering temperature.

Reducing NOx Emissions through Microwave Heating of Aftertreatment Systems for Sustainable Transport in the Inland Waterway Sector

The inland navigation sector makes a significant contribution to the growth of the global economy as well as to climate change due to pollutants emitted by diesel engines. NOx emissions are very high in port areas where, due to traffic, the ships run at idling regimes. Selective catalytic reduction (SCR) represents one of the most suitable technologies, in terms of cost effectiveness, but does not perform well if the temperature during vessel operation is lower than 180 °C. Microwave technology can support preheating of the ceramic core of SCR in order to increase the temperature towards the optimal interval for the best NOx reduction. Research has focused on coupling a magnetron head to a SCR device in order to evaluate to what extent the technology can meet the requirements of Stage V of the European Directive related to NOx emissions. Measurements of NOx emitted have been performed on engines with 603.5 kW nominal power and 1500 rpm that operate at a lower engine speed (700–1200 rpm) and output power (58–418 kW). The values recorded for emissions using microwave heating of ceramic core of SCR have decreased by 89% for a constant load of engine and idling engine speed.

Core Electron Heating by Triggered Ion Acoustic Waves in the Solar Wind

Abstract Perihelion passes on Parker Solar Probe orbits 6–9 have been studied to show that solar wind core electrons emerged from 15 solar radii with a temperature of 55 ± 5 eV, independent of the solar wind speed, which varied from 300 to 800 km s−1. After leaving 15 solar radii and in the absence of triggered ion acoustic waves at greater distances, the core electron temperature varied with radial distance, R, in solar radii, as 1900R −4/3 eV because of cooling produced by the adiabatic expansion. The coefficient, 1900, reproduces the minimum core electron perpendicular temperature observed during the 25 days of observation. In the presence of triggered ion acoustic waves, the core electrons were isotropically heated as much as a factor of two above the minimum temperature, 1900R −4/3 eV. Triggered ion acoustic waves were the only waves observed in coincidence with the core electron heating. They are the dominant wave mode at frequencies greater than 100 Hz at solar distances between 15 and 30 solar radii.

Constraining the CME Core Heating and Energy Budget with SOHO/UVCS

Abstract We describe the energy budget of a coronal mass ejection (CME) observed on 1999 May 17 with the Ultraviolet Coronagraph Spectrometer (UVCS). We constrain the physical properties of the CME’s core material as a function of height along the corona by using the spectra taken by the single-slit coronagraph spectrometer at heliocentric distances of 2.6 and 3.1 solar radii. We use plasma diagnostics from intensity ratios, such as the O vi doublet lines, to determine the velocity, density, temperature, and nonequilibrium ionization states. We find that the CME core’s velocity is approximately 250 km s−1, and its cumulative heating energy is comparable to its kinetic energy for all of the plasma heating parameterizations that we investigated. Therefore, the CME’s unknown heating mechanisms have the energy to significantly affect the CME’s eruption and evolution. To understand which parameters might influence the unknown heating mechanism, we constrain our model heating rates with the observed data and compare them to the rate of heating generated within a similar CME that was constructed by the MAS code’s 3D MHD simulation. The rate of heating from the simulated CME agrees with our observationally constrained heating rates when we assume a quadratic power law to describe a self-similar CME expansion. Furthermore, the heating rates agree when we apply a heating parameterization that accounts for the CME flux rope’s magnetic energy being converted directly into thermal energy. This UVCS analysis serves as a case study for the importance of multislit coronagraph spectrometers for CME studies.

Effects of temperature, analysis and modelling uncertainties on the reliability of base-isolated bridges in Eastern Canada

The seismic response of base-isolated bridges depends strongly on the seismic isolation system (SIS) properties, which typically vary under the effect of multiple conditions, such as temperature. The North American Bridge Design Codes and the EN-Eurocode 8 recommend a bounding analysis method in order to consider the effect of SIS properties variation with different conditions. However, this method is not founded on a rigorous probabilistic approach, and thus does not impact the reliability of base-isolated bridges. This paper presents an estimate of the seismic reliability and its variation range for a typical two-span concrete base-isolated bridge located in Montreal, a typical site for Eastern Canada. Temperature, bidirectional horizontal seismic hazard and the main parameters affecting the resistance of bridge components, specifically, dimensions, material properties of the bridge pier and SIS properties are all modelled as Random Variables (RVs). Bridge failure associated with two limit states is examined: (1) damage at the pier base by lack of bending moment capacity and (2) SIS failure due to a lack of displacement capacity. The Monte-Carlo method is used to evaluate each limit state’s reliability and probability of failure. In earlier studies, epistemic uncertainties (EUs) associated with the modelling and seismic analysis method were either ignored or not thoroughly considered. A main innovation of the present study is to include EUs associated with the seismic response analysis method and the lead core heating of the lead rubber bearing SIS are modelled as RVs. Their margins of variation are estimated, and their probabilistic distribution parameters are identified. The effects of these EUs on the reliability of the bridge are investigated. The effect of the natural rubber material type on the reliability of the bridge is also studied. Preliminary results show that, due to any of these uncertainties, the global reliability index is within a range of [3.36–3.62], whereas the reliability index when these EUs are not included is 3.49. When including the epistemic uncertainty associated with the response analysis method, the reliability index of the pier base flexural behaviour limit state varies between 3.52 and 3.76(as compared to a value of 3.56 obtained without including the above EUs). Similarly, when including the epistemic uncertainty associated with the heating effect, the reliability index of the SIS displacement limit state varies between 3.31, for an extreme effect, and 3.49 for a more representative effect (as compared toa value of 3.51 obtained without including the above EUs). Earlier studies considering fewer variability sources showed that the global seismic reliability varies between 3.47 and 3.52 for the same typical two-span base-isolated bridge in Montreal. In these studies, the SIS material and geometrical properties were considered deterministic. Other sites in Quebec have shown comparable reliabilities to those at the studied site, with a maximum variation of 3% between sites.

Mass Transfer and Stellar Evolution of the White Dwarfs in AM CVn Binaries

Abstract We calculate the stellar evolution of both white dwarfs (WDs) in AM CVn binaries with orbital periods of P orb ≈ 5–70 minutes. We focus on the cases where the donor starts as a M He < 0.2M ⊙ helium WD and the accretor is a M WD > 0.6 M ⊙ WD. Using Modules for Experiments in Stellar Astrophysics, we simultaneously evolve both WDs assuming conservative mass transfer and angular momentum loss from gravitational radiation. This self-consistent evolution yields important feedback of the properties of the donor on the mass-transfer rate, M ̇ , as well as the thermal evolution of the accreting WD. Consistent with earlier work, we find that the high M ̇ 's at early times forces an adiabatic evolution of the donor for P orb < 30 minutes so that its mass–radius relation depends primarily on its initial entropy. As the donor reaches M He ≈ 0.02–0.03 M ⊙ at P orb ≃ 30 minutes, it becomes fully convective and could lose entropy and expand much less than expected under further mass loss. However, we show that the lack of reliable opacities for the donor’s surface inhibit a secure prediction for this possible cooling. Our calculations capture the core heating that occurs during the first ≈107 yr of accretion and continue the evolution into the phase of WD cooling that follows. When compared to existing data for accreting WDs, as seen by Cheng and collaborators for isolated WDs, we also find that the accreting WDs are not as cool as we would expect given the amount of time they have had to cool.

Implications of parasitic absorption of electron cyclotron waves on ITER operation around half-field

The ITER Research Plan envision operation around half of the nominal magnetic field (i.e. around B = 2.65 T) as a path to baseline operation. This work discusses constraints on the optimal range of magnetic field, which is bounded in the lower limit by the presence of the third-harmonic electron cyclotron resonance at half field, and on the upper limit by the loss of core heating and current drive. It will be shown that increasing the magnetic field by only 3%, i.e. to 2.75 T, eliminates the third harmonic parasitic absorption without compromising demonstration of access to H-mode, while operating at a magnetic field of 3.0 T—previously proposed for optimal use of the ion cyclotron system—would impair the use of the electron cyclotron system for core-heating and current drive. Operation at 2.65 T would still be possible if the polarization of the equatorial launcher is changed from X-mode to O-mode in the current flattop phase.

Mid-infrared interband cascade light emitting devices grown on off-axis silicon substrates

The high-quality growth of midwave infrared light emitters on silicon substrates will advance their incorporation into photonic integrated circuits, and also introduce manufacturing advantages over conventional devices grown on lattice-matched GaSb. Here we report interband cascade light emitting devices (ICLEDs) grown on 4 degree offcut silicon with 12% lattice mismatch. Four wafers produced functioning devices, with variations from wafer to wafer but uniform performance of devices from a given wafer. The full width at half maxima for the (004) GaSb rocking curves were as narrow as ∼ 163 arc seconds, and the root mean square surface roughness as small as 3.2 nm. Devices from the four wafers, as well as from a control structure grown to the same design on GaSb, were mounted epitaxial-side-up (epi-up). While core heating severely limited continuous wave (cw) emission from the control devices at relatively modest currents, efficient heat dissipation via the substrate allowed output from the devices on silicon to increase up to much higher currents. Although the devices on silicon had higher leakage currents, probably occurring primarily at dislocations resulting from the lattice-mismatched growth, accounting for differences in architecture the efficiency at high cw current was approximately 75% of that of our previous best-performing standard epi-down ICLEDs grown on GaSb. At 100 mA injection current, 200-µm-diameter mesas produced 184 µW of cw output power when operated at T = 25 °C, and 140 µW at 85°C. Epi-up mid-IR light emitters grown on silicon will be far simpler to process and much less expensive to manufacture than conventional devices grown on GaSb and mounted epi-down.

Sintered Ti/Al core/shell nanoparticles: computational investigation of the effects of core volume fraction, heating rate, and room-temperature relaxation on tensile properties

Molecular dynamics simulations were performed to roughly imitate the conditions of selective laser sintering during additive manufacturing. The role of core volume fraction on the resultant uniaxial tensile properties of sintered Ti/Al bimetallic core/shell nanoparticles (NPs) was investigated during various sintering states. A chain model was created from five single thermally equilibrated Ti/Al NPs with weak neck connections by a solid-state sintering process at room temperature (298 K). The chains were heated to 800 K with two heating rates (0.04 and 0.2 K ps−1), underwent high-temperature relaxation, and were cooled to 298 K with a cooling rate of 0.08 K ps−1. They were then relaxed at 298 K for different periods (i.e. 1, 4, and 10 ns). In a follow-up procedure, those sintered NPs were subjected to uniaxial tension at different strain rates (i.e. 0.001, 0.01, and 0.1% ps−1). The thermodynamic properties and the structural evolutions of atomic configurations were investigated during the sintering process. The tensile responses were also obtained to examine the final product quality. The results indicate a strong correlation between the tensile strength of the final sintered chain product and the Ti core volume fraction. A larger Ti core volume fraction yields a stronger chain structure, resulting in higher tensile strength. The effect of heating rate on the tensile strength of final products with larger core volume fraction is more pronounced. The effect of room-temperature relaxation is not obvious on the tensile strength except for two products, which were sintered with the fast heating rate and tested under the lowest/highest strain rate. Also, high strain rates improve the tensile strength, and low strain rates will lead to enhanced ductility of the final products, especially with residual single atomic chain.

A smart magnetically separable MIL-53(Al) MOF-coated nano-adsorbent for antibiotic pollutant removal with rapid and non-contact inductive heat regeneration

Metal-organic framework (MOF), MIL-53(Al), coated magnetic nanoparticles (MNP) were developed in this work for highly efficient adsorption and removal of an antibiotic pollutant oxytetracycline (OTC) from water. The adsorbed OTC molecules, which are heat labile, can be degraded rapidly using inductive heating which also regenerates the nano-adsorbent. Polyethylene glycol (PEG) coated MNP was used as a seed for growing the MIL-53(Al) MOF. The MIL-53(Al) coating was achieved via a facile green synthesis route using deprotonated terephthalic acid in an aqueous alkaline solution. The MIL-53(Al) coating layer on the MNP was found to have low crystallinity compared to that of the pristine MIL-53(Al) possibly due to the mismatch growth on the PEG-coated MNP surface. Nevertheless, the obtained nano-sorbent displays high OTC adsorption capacity of 794 mg/g at optimal pH 8. The adsorbed OTC on the nano-sorbent can be destructed using a rapid non-contact inductive heating of the magnetic core. Adsorption and regeneration were carried out up to 9 cycles in the presence of OTC. FTIR and PXRD shows that OTC adheres strongly to the MIL-53(Al) framework which causes gradual MIL-53(Al) degradation after several cycles of heat regeneration. Nevertheless, the MIL-53(Al) coated MNP without the adsorbed OTC shows strong structural integrity even after 9 regeneration cycles. The work demonstrates the high potential of the developed nano-sorbent for use in pollutant removal, magnetic separation of toxic pollutants as well as rapid regeneration of the nano-sorbents using induction heating.

Hot Electron and Ion Spectra in Axial and Transverse Laser Irradiation in the GXII-LFEX Direct Fast Ignition Experiment

An electron spectrometer was used to measure the electron and ion spectra in two different irradiations of implosion laser to the deuterated spherical shell targets at the direct fast ignition experiments on the Gekko-LFEX facility. In the transverse irradiation against the LFEX laser axis, the low effective hot electron temperature (Teff) and huge neutron yield (Ny) could be obtained although high Teff and low Ny could be observed in the axial irradiation. In the transverse irradiation, the efficient core heating could be obtained because the laser-plasma interaction position is close to the core and the diffusive/ion drag heating may be effective.

Plasmon-pyroelectric nanostructures used to produce a temperature-mediated reactive oxygen species for hypoxic tumor therapy

Photodynamic therapy (PDT) has attracted considerable attention for tumor treatment, however, its efficacy is dramatically limited by the low reactive oxygen species (ROS) generation efficiency at hypoxic tumor microenvironment. Herein, new plasmon-pyroelectric gold (Au)@barium titanate (BTO) core-shell (CS) nanostructures (NSs) were designed to produce a temperature-mediated oxygen (O2)-independent PDT for hypoxic tumor therapy. Upon 808 nm laser irradiation, the plasmonic heating of Au cores was excited and transferred a heat to pyroelectric BTO shell, where the temperature elevation could decrease spontaneous polarization of BTO, leading to abundant hole released from the BTO surface and promoting to hydroxyl radical formation through an O2-independent approach. Simultaneously, [email protected] CSNSs still remain excellent photothermal performance originating from Au cores. Actually, 808 nm laser irradiated and polyethylene glycol modified [email protected] CSNSs could exhibit promising phototherapeutic effects on 4T1 cells at hypoxic conditions and 4T1 tumor-bearing mice, showing great potential for hypoxic tumor therapy.

Novel Method of Search for Transparent Optical Materials with Extremely High Melting Point

We propose a novel crystal growth method, “Core Heating (CH) Method”, which is suitable for a search of novel materials with extremely high melting points above the melting (softening) point of an Ir crucible. As a feasibility test of the novel CH method, we fabricated the conventional material, (Y0.99Ce0.01)3Al5O12 (Ce:YAG), with a melting point of ∼1970 °C, because this material can be grown by the conventional melt growth technique like the micropulling down (μ-PD) method for the comparison. We compared scintillation properties for Ce:YAG prepared by the CH and μ-PD methods in order to find if the CH method can be applied to the material search. The crystals grown by both methods showed the YAG single-phase, and almost all their optical and scintillation properties of them were comparable for both samples. Particularly, the light output of Ce:YAG crystal grown by the CH method (20,000 ± 1,000 photons/MeV) was similar to that of the sample grown by the μ-PD method (23,000 ± 1,000 photons/MeV). Therefore, we concluded that the CH method is a useful technique for the search of scintillation materials with extremely high melting points.

Simulation of a Station Blackout Accident for the SMART Using the CINEMA Code

SMART is a small-sized integral type PWR containing major components within a single reactor pressure vessel. Advanced design features implemented into SMART have been proven or qualified through experience, testing, or analysis according to the applicable approved standards. After Fukushima accident, a rising attention is posed on the strategy to cope with a Station Blackout (SBO) accident, which is one of the representative severe accidents related to the nuclear power plants. The SBO is initiated by a loss of all offsite power with a concurrent failure of both emergency diesel generators. With no alternate current power source, most of the active safety systems that perform safety functions are not available. The purpose of SBO analysis in this paper is to show that the integrity of the containment can be maintained during a SBO accident in the SMART (System-integrated Modular Advanced ReacTor). Therefore, the accident sequence during a SBO accident was simulated using the CINEMA-SMART (Code for INtegrated severe accidEnt Management and Analysis-SMART) code to evaluate the transient scenario inside the reactor vessel after an initiating event, core heating and melting by core uncovery, relocation of debris, reactor vessel failure, discharge of molten core, and pressurization of the containment. It is shown that the integrity of the containment can be maintained during a SBO accident in the SMART reactor. It has to be mentioned that the assumptions used in this analysis are extremely conservative that the passive safety systems of PSIS and PRHRS were not credited. In addition, as ANS73 decay heat with 1.2 multiplier was used in this analysis, actual progression of the accident would be much slow and amount of hydrogen generation will be much less.

Influence of superstructure modeling approach on the response prediction of buildings with LRBs considering heating effects

The aim of this study is to investigate the variation in response quantities of buildings seismically isolated by lead rubber bearings (LRBs), depending on how the superstructure is modeled in the analyses. For this purpose, two distinct seismically isolated structures with 4- and 9-stories are idealized by (i) a single-degree-of-freedom model (SDOF), (ii) a two-degree-of-freedom model (2DOF), (iii) a 3D model and subjected to near-fault earthquake excitations through nonlinear response history analyses (NRHA). In all of the structural models, the hysteretic behavior of LRBs is represented by a deteriorating force–displacement curve in which the strength of bearing decreases gradually during cyclic motion due to the lead core heating. Analyses are performed by OpenSees and the response quantities considered are floor drifts and floor accelerations for superstructures and maximum isolator displacements for isolation systems. In order to assess the influence of the superstructure modeling approach on selected response quantities, results of analyses with SDOF, 2DOF, and 3D models are compared with each other. Furthermore, in order to highlight the significance of hysteretic representation used to model LRBs, a non-deteriorating force–displacement curve, where lead core heating phenomenon is ignored, is also considered to idealize LRBs in the case of a 3D superstructural model. Results showed that the SDOF model overestimates the isolator displacements obtained from the 3D model and the 2DOF model is effective only in estimating mid-story response quantities of the 3D model.

Verification of fast heating of core plasmas produced by counter-illumination of implosion lasers

We conducted fast heating of a core plasma produced by counter-illumination of two beam bundles of implosion lasers for two incident directions of the heating laser. For the axial heating configuration, wherein the heating laser was incident along the coaxial direction of the implosion lasers, the size and density of the counter-imploded core plasma were estimated. The incident timing of the heating laser was determined. Although the heating laser was incident during the stagnation of the core plasma, there were no considerable increases in the intensity of X-rays with energies beyond 1 keV and the yield of the thermonuclear fusion neutrons. Effective core heating did not occur due to the interaction of the heating laser with the low-density ablated plasma far from the core. On the other hand, for the transverse heating configuration, wherein the heating laser was incident from the transverse direction of the implosion laser axis, optimization of the incident timing of the heating laser was not achieved. However, two-dimensional radiation-hydrodynamic simulation revealed that a heating laser can directly interact with a core plasma and effective heating is expected. In our scheme, transverse heating configuration appears to be significant.

Flame spread over polyethylene-insulated copper and stainless-steel wires at high pressure

This work studied flame spread over polyethylene (PE)-insulated wires at high pressure with an emphasis on the effect of ambient pressure. Laboratory simulated wires were used as a tested wire, which consisted of semi-transparent low-density PE (LDPE) tube as an insulation and copper (Cu) rod or stainless-steel (SS) tube as a core. Increasing ambient pressure produced much soot, leading to an intensively yellow luminous flame. Flame spread rate for Cu rod increased with ambient pressure, whereas that for SS tube decreased. A qualitative analysis via a simplified flame spread model shows that the flame heat flux increases with ambient pressure, but consequently the flame heating decreases due to the decreased flame heating length. Therefore, the flame spread rate for SS tube decreased with increasing ambient pressure. For Cu rod, however, the core heating is dominant enough to compensate the decreased flame heating, and thus the ambient pressure positively affected the flame spread. During the flame spread, melted insulations were often dripped down, but it reduced with increasing ambient pressure. For Cu rod, no dripping occurred when further increasing ambient pressure, which indicates that there is the dripping limit at a high-pressure region. These findings should contribute to electrical fire safety in elevated pressure environments.

Numerical Simulation and Validation for Early Core Degradation Phase under Severe Accidents

Early core degradation determines the amount of hydrogen generated by cladding oxidation as well as the temperature, the mass, and the composition of corium that further relocates into the lower head of reactor pressure vessel (RPV), which is essential for the effectiveness analysis of in-vessel retention (IVR) and hydrogen recombiners. In this paper, the mechanisms of controlling phenomena in the early phase of core degradation are analysed at first. Then, numerical models adopted to calculate (1) core heating up, (2) cladding oxidation, (3) dissolution between molten zirconium and fuel pellets, and (4) formation of a molten pool in the core active section are presented. Compared with integral codes for severe accident analysis (such as MAAP and MELCOR), the models in this paper are established at the fuel pin level and the calculation is performed in 3D, which can capture the detail local phenomena during the core degradation and eliminate the average effect due to equivalent rings used in integral codes. In addition, most of the control equations in this paper are calculated by implicit schemes, which can improve the accuracy and stability of the calculation. In the simulation, the calculation oxidation is calculated by using the oxygen diffusion model, while the dissolution is calculated with Kim, Hayward, Hofmann, and IBRAE models to perform uncertainty analysis. For the validation, the cladding oxidation model is verified by Olander theoretical cases in the conditions of both steam-rich and steam-starved. The dissolution models are validated by the RIAR experiment. The code is overall verified by Phebus FPT0 on the integral phase of core early degradation. According to the simulation results, it can be inferred that the dissolution reaction between the molten zirconium and fuel pellets is the main reason for the melting of UO2 at low temperature. In the case of starved steam, part of the fuel pellets can melt down even at 2248 K and relocate to the bottom of the core, which is much lower than the melting point of UO2 (3113 K).

Ignition Delay of Fluorinated Ethylene Propylene Wire Insulation in a Forced Flow Field in Microgravity

Fluorinated ethylene propylene (FEP) wire insulation ignition is investigated in a forced flow field in microgravity and normal gravity with a continuous current. First, FEP insulation melts and decomposes, causing jet bursting in both normal gravity and microgravity. Second, the forced flow and gravity produce minor effects on the core heating and bursting time, while the pyrolysis time increases slightly with increasing air velocity. Third, the positively stretch rates in terms of the velocity gradients are higher in microgravity. Both the forced flow and gravity have significant effects on the induction time, which is dependent on the stretch rate and Damkohler number. The induction time increases with increasing air velocity, and it is higher in microgravity. Finally, the ignition delay time is dominated by the core heating and bursting time, while its bigger value and faster increase in microgravity with increasing air velocity are dominated by the induction time.