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Abstract: A new method named direct profile extrapolation (DPE) has been developed to estimate the radial profiles of temperature and density in a fusion reactor. This method directly extrapolates the radial profiles observed in present experiments to the fusion reactor condition assuming gyro-Bohm type parameter dependence. The magnetohydrodynamic equilibrium that fits the experimental profile data is used to determine the plasma volume. Four enhancement factors for the magnetic field strength, the density, the plasma beta, and the energy confinement are assumed. Then, the plasma size is determined so as to fulfill the power balance in the reactor plasma. The plasma performance can be measured by an index, C exp, introduced in the DPE method. The minimum magnetic stored energy of the fusion reactor to achieve self-ignition is shown to be proportional to the cube of C exp and inversely proportional to the square of magnetic field strength. Using this method, the design window of a self-ignited fusion reactor that can be extrapolated from recent experimental results in the Large Helical Device (LHD) is considered. Also discussed is how large an enhancement is needed for the LHD experiment to ensure the helical reactor design of FFHR2m2. [Copyright &y& Elsevier]

Limited operating experience with hydrogen energy systems in consumer environments is recognised as a significant barrier to the implementation of the required infrastructure. Significant international effort has been initiated to develop relevant codes and standards. To prevent emerging codes, standards and local regulations from being unnecessarily restrictive, real operating experience is needed using full-scale experimental trials. This paper begins with an overview of experimental work commissioned by both the regulator and industry to help quantify the hazards and risks. It then summarises work co-funded by the GB regulator and EU on: * Jet releases, barriers to reduce safety distances and self ignition undertaken using high pressure hydrogen compression, storage and release equipment. * Liquid hydrogen spills from a road tanker through a vacuum insulated transfer hose. Findings include: jets are predominantly momentum-driven; a 60° barrier reflects less heat back to the source than a 90° barrier; the lowest burst pressure for self-ignition is 3.55 MPa; and initial findings suggest a pool can be formed if a liquid release is made onto the ground. The experimental data from this work has been used to establish safety distances, and define conditions under which self-ignition may occur. [ABSTRACT FROM AUTHOR]

The process of ignition of the solid fuel from glycidyl azide polymer in the mini-engine of a microelectromechanical system has been considered. Macrokinetic calculations of the self-ignition temperature of the fuel and the induction period for different heat transfer conditions have been made. On the basis of the critical thermal flux determination, recommendations on the choice of the minimum power and size of the thermistor in the igniter of the solid-fuel mini-engine have been formulated. [ABSTRACT FROM AUTHOR]

Abstract: The self-ignition of low alkylbenzenes at engine-relevant conditions has been studied with kinetic modeling. A previously developed chemical kinetic model for gasoline surrogate fuels [J.C.G. Andrae, R.A. Head, Combust Flame 156 (2009) 842–51] was extended with chemistry for ethylbenzene and m-xylene resulting in an overall model consisting of 150 species and 759 reactions. In model validation, comparisons were made between model predictions and experimental data of ignition delay times measured behind reflected shock waves, laminar burning velocities collected at elevated temperature and pressure and species profiles in a high-pressure single pulse shock tube. Generally good agreement was found and the model is sensitive to changes in mixture strength, pressure and temperature. Shock tube ignition delay modeling results for ethylbenzene and m-xylene also compare well to the ones for toluene. The rate controlling step for the ignition of ethylbenzene in the current mechanism is the reaction with ethylphenyl radical and oxygen. Ignition delay time for m-xylene was found to be very sensitive to reactions involving hydrogen atom abstraction from fuel by hydroxyl and oxygen and to branching reactions where methylbenzyl reacts with oxygen and hydroperoxide. The validated mechanism was used to study fuel chemistry effects when blending ethylbenzene with the paraffinic fuels iso-octane and n-heptane. A sensitivity- and flow path analysis showed that a higher consumption of hydroperoxide by ethylphenyl than expected from the contribution of neat ethylbenzene in a fuel mixture with iso-octane inhibits both iso-octane and ethylbenzene ignition. This can explain the observed increase in ignition delay time and octane number for fuel mixtures compared to neat fuels. [Copyright &y& Elsevier]

Abstract: The high temperature oxide thermoelectric materials of p-type Ca3Co4−x Ag x O9 (denoted as p-Co349/Ag x ) and n-type Ca1−y Sm y MnO3 (denoted as n-Mn113/Sm y ) were prepared by the self-ignition method combined with a sintering technique. The influence of doping Ag and Sm on the thermoelectric properties of the corresponding materials was evaluated. The figures of merit, ZT, for the p-Co349/Ag0.2 and n-Mn113/Sm0.02 materials reached maxima of 0.20 and 0.15 at 973K, respectively. The performances of thermoelectric devices constructed with the p- and n-type pairs were evaluated in terms of the maximum output power (P max) and manufacturing factor. The P max and volume power density for the four-leg devices reached 36.8mW and 81.9mWcm−3 at ΔT of 523K, respectively. [Copyright &y& Elsevier]

Lignite self-ignition generated two major problems for the management of mining exploitation, namely: an economical one, as are compromised enormous coal quantities, and the other regarding air quality, in the atmosphere being eliminated important quantities of sulphur oxides, azoth oxides, carbon monoxide and ash. Starting from these aspects, this paper presents the results of monitoring the noxae emission and of the temperature realized at a self-alight coal deposit. [ABSTRACT FROM AUTHOR]

Abstract: The development of novel air-breathing engines such as supersonic combustion ramjets (scramjets) depends on the understanding of supersonic mixing, self-ignition and combustion. These aerothermochemical processes occur together in a scramjet engine and are notoriously difficult to understand. In the present study, we aim at analyzing the HyShot II scramjet combustor mounted in the High Enthalpy Shock Tunnel Göttingen (HEG) by using Reynolds Averaged Navier Stokes (RANS) and Large Eddy Simulation (LES) models with detailed and reduced chemistry. To account for the complicated flow in the HEG facility a zonal approach is adopted in which RANS is used to simulate the flow in the HEG nozzle and test-section, providing the necessary inflow boundary conditions for more detailed RANS and LES of the reacting flow in the HyShot combustor. Comparison of predicted wall pressures and heat fluxes with experimental data show good agreement, and in particular does the LES agree well with the experimental data. The LES results are used to elucidate the flow, mixing, self-ignition and subsequent combustion processes in the combustor. The combustor flow can be separated into the mixing zone, in which turbulent mixing from the jet-in-cross flow injectors dominates, the self-ignition zone, in which self-ignition rapidly takes place, and the turbulent combustion zone, located towards the end of the combustor, in which most of the heat release and volumetric expansion takes place. Self-ignition occurs at some distance downstream of the injectors, resulting in a distinct pressure rise further downstream due to the volumetric expansion as observed in the experiments. The jet penetration is about 30% of the combustor height and the combustion efficiency is found to be around 83%. [ABSTRACT FROM AUTHOR]

Abstract: Combustion characteristics of liquid hydrocarbon fuels are studied in a model combustor of SCRAM jet engines. The Mach number and total pressure of main flow in the combustor are 2.0 and 0.38MPa, respectively, and the total temperature is varied from 1800 to 2400K. Five kinds of n-alkane fuels such as n-heptane, n-octane, n-decane, n-tridecane and n-hexadecane are employed in experiments. Fuels are injected with a carrier nitrogen gas perpendicular to the mail flow in the combustor and the self-ignition behavior is investigated. The results show that the liquid fuels with lower carbon number have better self-ignition performance. This suggests that physical properties of liquid fuels such as volatility have a dominant effect on the self-ignition. The flame-holding behavior is investigated with the addition of pilot hydrogen to carrier nitrogen gas. The critical equivalence ratio at which the stable combustion keeps after cut-off of the pilot hydrogen is obtained. The relationship between the critical equivalence ratio and carbon number of fuel shows that fuels with the carbon numbers from 8 to 10 have the best flame-holding performance among the tested fuels. These experimental results can be expressed qualitatively by the simplified analysis with the concept of physical and chemical induction times. [ABSTRACT FROM AUTHOR]

Abstract: Hydrogen is expected to be used as a clean energy carrier. However, when high-pressure hydrogen is suddenly released into the air through tubes, self-ignition can occur by a diffusion ignition mechanism. In this paper, the phenomena of self-ignition and flame propagation during the sudden release of high-pressure hydrogen were investigated experimentally. Experimental results show that self-ignition can occur when bursting pressure is sufficiently high in spite of the shortness of the tube. For example, self-ignition was observed at a bursting pressure as high as 23.5MPa with 50mm long tube. When self-ignition successfully occurs, a hydrogen jet flame is produced by the ignition. The flame is then stabilized at the tube outlet. From photodiode signals and flame images, the propagation of a flame inside the tube is confirmed and the flame is detected near the rupture disk as the bursting pressure increases. When the tube length is not long enough to produce self-ignition, a hydrogen flame is observed in the only boundary layer at the end of tube and it quenches after the flame exits the tube. Consequently, the formation of a complete flame across the tube is important to initiate self-ignition, which sustains a diffusion flame after jetting out of the tube into the air. Also, in order to establish a complete flame across the tube, it is necessary to have sufficient length such that the mixing region is generated by multi-dimensional shock–shock interactions. [ABSTRACT FROM AUTHOR]

Abstract: An apparent relation between the lift-off length under diesel conditions and the ignition quality of a fuel has previously been reported. To cast light on the underlying mechanism, the current study aims to separate flame lift-off effects of the chemical ignition delay from those of other fuel properties under diesel conditions. Flame lift-off was measured in an optical diesel engine by high-speed video imaging of OH-chemiluminescence. Fuel and ambient-gas properties were varied during the experiment. Only a weak correlation was found between ignition delay and lift-off length. The data indicate that this correlation is due to a common, stronger correlation with the ambient oxygen concentration. The chemical ignition delay and the fuel type had similar, weak effects on the lift-off length. A recently proposed mechanism for lift-off stabilization was used to interpret the results. It assumes that reactants approaching the lift-off position of the jet are mixed with high-temperature products found along the edges of the flame, which trigger autoignition. In this picture, the fuel effect is most likely due to differences in the amount of mixing with high-temperature products that is required for autoignition. In the current experiment, all lift-off effects seem to arise from variations in the reactant and product temperatures, induced by fuel and ambient properties. [ABSTRACT FROM AUTHOR]

The paper discusses a critical situation regarding municipal solid waste (MSW) in Donetsk city (Ukraine) as a suitable example. Special attention is given to such problems as biodegradation and self-ignition of MSW dumps as well as the hazard of dioxins that might be present in the emitted gases. The paper describes the materials as well as techniques used for experiments and calculations of results. The paper offers theoretical calculations of biogas emissions from MSW landfill bodies as well as the results of experimental measurements performed within laboratory conditions of a "MSW micro-landfill". Dynamics of development of microorganism colonies within the body of MSW has been studied experimentally and a mathematical model of these processes was developed. There was calculated a volume of leachate ("MSW-sewage") produced at MSW landfills as well as migration of toxic waste from the leachate to underground water and soil surrounding MSW landfills of Donetsk. MSW self-ignition processes taking place within waste layers and diffusion of toxic fire-hazardous gases have been studied both theoretically and experimentally. There have been developed and proposed techniques of forecasting and prevention of MSW self-ignition within MSW layers. Processes of MSW incineration together with resinous industrial waste have been studied within the framework of experiments, namely: there were measured emissions of toxic combustion gases and heavy metals as well as "distribution" of the latter in combustion gases and ash. [ABSTRACT FROM AUTHOR]

Abstract: Cold startability of automotive direct injection (DI) Diesel engines is frequently one of the negative features when these are compared to their closest competitor, the gasoline engine. This situation worsens with the current design trends (engine downsizing) and the emerging new Diesel combustion concepts, such as HCCI, PCCI, etc., which require low compression ratio engines. To mitigate this difficulty, pre-heating systems (glow plugs, air heating, etc.) are frequently used and their technologies have been continuously developed. For the optimum design of these systems, the determination of the threshold temperature that the gas should have in the cylinder in order to provoke the self-ignition of the fuel injected during cold starting is crucial. In this paper, a novel methodology for estimating the threshold temperature is presented. In this methodology, experimental and computational procedures are adequately combined to get a good compromise between accuracy and effort. The measurements have been used as input data and boundary conditions in 3D and 0D calculations in order to obtain the thermodynamic conditions of the gas in the cylinder during cold starting. The results obtained from the study of two engine configurations -low and high compression ratio- indicate that the threshold in-cylinder temperature is a single temperature of about 415 °C. [Copyright &y& Elsevier]

Abstract: Agricultural products stored in silos, and their dusts, can undergo oxidation and self-heating, increasing the risk of self-ignition and therefore of fires and explosions. The aim of the present work was to determine the thermal susceptibility (as reflected by the Maciejasz index, the temperature of the emission of flammable volatile substances and the combined information provided by the apparent activation energy and the oxidation temperature) of icing sugar, bread-making flour, maize, wheat, barley, alfalfa, and soybean dusts, using experimental methods for the characterisation of different types of coal (no standardised procedure exists for characterising the thermal susceptibility of either coal or agricultural products). In addition, the thermal stability of wheat, i.e., the risk of self-ignition determined as a function of sample volume, ignition temperature and storage time, was determined using the methods outlined in standard EN 15188:2007. The advantages and drawbacks of the different methods used are discussed. [Copyright &y& Elsevier]

In order to prevent the spontaneous ignition of nitrocellulose (NC), NC is stabilized by washing with industrial water in its synthesis process. However, there is a possibility that the components in industrial water contribute to the thermal stability of NC. In this way, the purpose of this study is to clarify the effect of industrial water components on the thermal stability of NC. In experiments, a heat flux calorimeter was used to observe the thermal behavior of NC with the residue of vaporized industrial water. The induction period of heat release of NC with 2-mass% residues was approximately 2–5 h shorter than that of NC alone whose induction period was observed at 7 h. Those results indicate that the residue destabilized NC. On the other hand, when the additive amount of the residue was increased, the induction period gradually increased as well. Based upon these results, we assume that inorganic salts contributing to stabilization and destabilization competitively coexist in the industrial water components. The same thermal analysis was performed on NC with CaCO3, CaSO4, CaCl, ZnSO4, NaCl, and CuCl. Those salts are predicted to exist in the industrial water. In the results, the induction period of NC with 2-mass% CaCO3 was approximately 15-h longer than that of NC alone, while the induction period with the inorganic salts CaSO4, CaCl, ZnSO4, NaCl, and CuCl was 4–5-h shorter. Therefore, when the industrial water components accumulate in NC, the destabilization by inorganic salts such as CaSO4, CaCl, ZnSO4, NaCl, and CuCl and the stabilization by compounds such as CaCO3 are thought to countervail against each other. [ABSTRACT FROM AUTHOR]

A study has been made of the distinctive features of self-ignition and combustion of fuel-air mixtures containing methane, hydrogen, and ethylene in adiabatic compression. [ABSTRACT FROM AUTHOR]

Abstract: Hydrogen is expected to serve as a clean energy carrier. However, since there are serious ignition hazards associated with its use, it is necessary to collect data on safety in a range of possible accident scenarios so as to assess hazards and develop mitigation measures. When high-pressure hydrogen is suddenly released into the air, a shock wave is produced, which compresses the air and mixes it with hydrogen at the contact surface. This leads to an increase in the temperature of the hydrogen–air mixture, thereby increasing the possibility of ignition. We investigated the phenomena of ignition and flame propagation during the release of high-pressure hydrogen. When a hydrogen jet flame is produced by self-ignition, the flame is held at the pipe outlet and a hydrogen jet flame is produced. From the experiment using the measurement pipe, the presence of a flame in the pipe is confirmed; further, when the burst pressure increased, the flame may be detected at a position near the diaphragm. At the pipe outlet, the flame is not lifted and self-ignition is initiated at the outer edge of the jet. [Copyright &y& Elsevier]

In industries related to fossil energy, coal dust is often deposited at an angled position. A two–step parallel coal dust oxidation reaction mechanism is used to study the self–ignition and combustion characteristics of coal dust under inclination conditions. The consumption and transfer of multiple substances are considered. In addition, the gravity direction is used to simulate the influence of the inclination conditions on ignition characteristics of coal dust. Firstly, the reliability of the numerical model is verified, and the time series characteristics of the self–ignition and combustion of coal dust are studied. Then the characteristic parameters and evolution of self–ignition and combustion under different inclination are analyzed. The results show that under hot plate conditions, the ignition and combustion process of coal dust can be divided into five stages. The minimum ignition temperature of the coal dust layer (MITL) changes sinusoidally with the inclination angle. Coal dust deposited under the ceiling is easier to be ignited. As the temperature of the hot plate increases, the ignition delay time (IDT) is shortened. It is necessary to adjust the fire safety management according to the inclination conditions of the coal dust, especially in the area with an inclination angle of 150°–180°. [Display omitted] • Self-ignition and combustion characteristics of coal dust at different inclined angles are revealed. • MITLs change sinusoidally with the inclination angle. • Coal dust deposited under the ceiling is easier to be ignited. • Increasing of hot plate temperature leads to the advance of coal dust thermal runaway. • Hot spot moves from the inside to the surface, spreads on the surface, and moves from the surface to the inside. [ABSTRACT FROM AUTHOR]

• The minimum release pressure for self-ignition is significantly higher. • The decrease of binary mixture self-ignition enhances with fuel molecular weight. • Nitrogen addition effectively inhibits flame development inside the tube. • Nitrogen-weaken ignited flame spouting from tube exit tends to blow out. • When self-ignition occurs, a partially premixed flame evolves first. This paper reports on the nitrogen addition effects on the self-ignition of high-pressure hydrogen leakage. It reveals that the intensity of produced incident shock decreases with more nitrogen addition, unbeneficial for self-ignition occurrence. Besides, nitrogen addition in hydrogen significantly reduces self-ignition possibilities inside the tube and self-sustained jet flame formation outside the tube. There exists a certain critical threshold of shock overpressure of about 1 MPa for self-ignition occurrence at different nitrogen additions. In our experiments, the impurity gases (N 2 , CO, CH 4) reduce the self-ignition possibilities in the same order as it reduces the shock intensity, namely, the effect of N 2 is similar to that of CO, larger than that of the same volume of CH 4. It suggests that the decrease of binary mixture self-ignition can be mostly explained by the reduction of shock intensity, and the decrease effect enhances with fuel molecular weight. Furthermore, nitrogen addition inhibits the flame development and propagation inside the tube. Nitrogen-weaken ignited flame barely survives during the expansion outside the tube or is soon extinguished inside the tube with more nitrogen addition. Moreover, the flame has a rapid flame length growth rate of 1–2 mm/μs in the initial stage, but the expanding velocity becomes lower to 0–1 mm/μs after a period of spread. Accordingly, a mechanism of the self-ignition process for high-pressure hydrogen release is proposed for cases with 0%-7.5% nitrogen addition. [ABSTRACT FROM AUTHOR]

Abstract: Expert investigations were developed for a leak followed by fire in a natural gas measurement and regulation station, located in the Southern part of South America. Field inspections, chemical and microstructural tests, mechanical tests and models, and models for deflagration and detonation are presented and discussed. The fire was due to air that got into the pipes, when mounting valves at the pig traps. Venting and bleeding failed to be properly carried out while the line was pressurized, and the filling rate was not regulated properly either. In order to reduce the probability of recurrence of the event, the procedure for the filling and the pressurization of the pipeline was redesigned, safety features added, and personnel trained. [Copyright &y& Elsevier]

The self-ignition of methane-air mixtures is analyzed in conditions relevant for Homogeneous Charge Compression Ignition (HCCI) engines from both (i) experimental, and (ii) numerical modeling points of view. On the one hand, a Rapid Compression Machine (RCM) is retained as a pertaining experimental setup to carry out the first part of the study. On the other hand, the PDF method is the modeling framework chosen to describe the coupling between detailed chemical description and turbulent fluctuations. The emphasis is on the influence of the temperature heterogeneities induced by heat transfer during the compression stroke on the subsequent ignition process. Such temperature heterogeneities have already been observed in RCMs (Mittal and Sung, 2006), and they are qualitatively assessed by schlieren imaging in the present study. The simultaneous analysis of the pressure traces and direct visualizations allows to discriminate two distinct modes of ignition exhibiting different levels of coherence of the exothermic process. It is shown that the appearance of one or the other of these two modes is directly related to the temperature distribution at the onset of ignition. Then, the information gathered through the experimental results is used to check the ability of a simplified model to reproduce both qualitatively and quantitatively the observed results. The comparison with the experimental data suggests that the proposed modeling approach provides a well suited framework for further modeling studies of HCCI combustion. [ABSTRACT FROM AUTHOR]

Abstract: Hydrothermal treatment of the high-moisture containing (59%) Loy Yang brown coal was conducted in a 20 ml stainless steel autoclave at 200 to 350 °C for 30 and 180 min. Three treatment methods were employed: 1) conventional method (i.e., extra water was added before treatment); 2) as-received method (i.e., treatment without addition of extra water); and 3) separation method (i.e., treatment with physical separation of water and solid). Treatment using the as-received method revealed that hydrothermal conditions can be maintained in the autoclave without addition of extra water. Upgrading using the separation method yielded more effective drying especially during treatment at 350 °C, where the water content was reduced to 6%. Treatment above 250 °C led to progressive lower water content, increasing carbon and decreasing oxygen content. Calculations of the calorific values of the upgraded coals showed that hydrothermal treatment at 300 and 350 °C led to a net increase in the calorific value compared to the raw coal. Reductions in the volatile content and the changes in the physical properties of the upgraded coals significantly reduced self-ignition tendencies of the coal treated above 300 °C. [Copyright &y& Elsevier]

Regimes of self-ignition of the fuel mixture obtained by controlled separate injection of hydrogen and air into a plane-radial vortex chamber with a rapid (0.2 msec) transition to detonation have been realized for the first time. Self-ignition occurs in the stoichiometric region with a slightly higher (up to 6–30%) content of hydrogen and, normally, in a subsonic flow. The energy of guaranteed detonation initiation is determined for combustors of different geometries and different ratios of fuel components by using a thermal pulse produced by blasting a wire by electric current. Detonation initiation is ensured by using energy of 0.1 J. It is found that the main contribution of energy into the flow of the mixture occurs at the stage of evaporation (ionization) of copper of the blasted wire. The continuous spin detonation regime is found to decay as the exit cross section of the combustor is reduced. In the regime of combustion, both detonation and conventional turbulent combustion, the pressure at the periphery of the plane-radial vortex chamber is lower and the pressure at the edge of the exit orifice is higher than that in the case of exhaustion of cold fuel components. [ABSTRACT FROM AUTHOR]

Abstract: A catalytic Pt-based microdevice is evaluated for the combustion of hydrogen and/or propane. It is found that in confined ceramic microchannels hydrogen/air mixtures self-ignite over a wide range of compositions. This discovery is capitalized to self-ignite propane/air mixtures with the assistance of hydrogen addition. It is shown that propane kinetically inhibits hydrogen catalytic combustion at low hydrogen fractions. The minimum hydrogen composition for self-ignition of propane/air mixture compositions is found to be relatively constant, irrespective of propane composition. The transient and steady state behavior of these systems is described, and the minimization of hydrogen usage and startup time are discussed. [Copyright &y& Elsevier]

The storage of unsorted industrial waste (IND) fuel and refused-derived fuel (RDF) in piles at two different locations in Sweden was investigated. The objective was to assess the feasibility of waste storage in open areas for later energy utilization, and to study the physical, biological and chemical processes that occur during storage, by monitoring a number of parameters. One monitored IND pile showed an increase in temperature from an average of 49±10 to 73±7 °C, accompanied by considerable fluctuations in the waste mass interstitial oxygen and carbon dioxide concentrations during the first month of storage. Thereafter, steady-state conditions were registered for about 4 months, with an average pile temperature of 77±8 °C, interstitial oxygen concentration varying from below the detection limit up to 5% by volume, interstitial carbon dioxide concentrations varying from 0.2 to 18%, and interstitial methane concentrations varying from below detection limit up to 0.5%. After 6 months of storage, spontaneous combustion occurred in the monitored IND pile. This was preceded by strong winds, which ventilated the pile and increased its oxygen content. Spontaneous combustion was also observed in one RDF pile after the same storage time (about 6 months). The leachate produced as a result of the large quantity of water used in an attempt to douse the burning RDF pile showed higher concentrations of chemical oxygen demand, biochemical oxygen demand, total nitrogen, total oxidized nitrogen, total phosphorus and the heavy metals lead, cadmium and chromium than the median values in the leachate from municipal solid waste (MSW) landfill and from MSW incineration residues (50% fly ash) landfill. Baling to reduce waste fuel porosity is suggested as a safer option for the storage of waste material for energy recovery purposes. [Copyright &y& Elsevier]

The storage and transport of cereals and foodstuffs present recurrent problems. They may be attacked by insects or, under certain conditions, they may undergo spontaneous fermentation. Insect attack is normally avoided by fumigants, while fermentation, which depends on parameters such as temperature and humidity, is more difficult to stop and can produce chemical compounds which irremediably modify the nutritional and compositional properties of foodstuff. This paper describes the main chemical compounds produced by fermentation and self-ignition of soybean and rapeseed meal. Reported cases occurred in a storage site and during transport by ship, respectively. [Copyright &y& Elsevier]

The mechanism of the oxidation of coal at low temperatures, i.e., below 100°C, was examined using measurements of the gases emitted from a bed of coal in an isothermal flow reactor. Employing an online two-column micro gas chromatograph, transient rates of production of CO2 and CO were monitored during desorption and oxidation experiments. A bituminous coal was milled into three nominal top size classes: 0–0.5 mm, 0–1 mm, and 0–2 mm. Desorption experiments with unoxidized coal samples at 20–70°C indicated that even an unoxidized coal incorporates oxygenated complexes in its structure. The threshold for thermal decomposition of these oxygenated species was found to be between 50 and 70°C. Carbon oxides liberated from oxidizing coal were compared with those from the thermal decomposition of coal oxidized at the same temperature, suggesting that two parallel reaction sequences contribute to the emission of carbon oxides during oxidation. A multi-step reaction mechanism was also proposed to describe low-temperature oxidation of coal and to explain the phenomena observed during the desorption and oxidation experiments. [Copyright &y& Elsevier]

The phenomenon of gaseous thermal explosion within inert insulation material filled with a combustible evaporating fuel is considered. A novel approach to estimate the activation energy is suggested using the available experimental data and the relevant theoretical predictions concerning the delay ignition time. [Copyright &y& Elsevier]

• The shock wave and self-ignition of hydrogen in the arc-shaped tube are studied. • Reflected shock waves generated in the bend will spread both upstream and downstream. • Changing the position of the bend can promote or inhibit self-ignition. • Two possible processes of self-ignition are summarized. The self-ignition is a potential risk during the use of hydrogen, and arc-shaped bends exist in industrial hydrogen pipelines. So the experimental and numerical study were conducted to investigate the shock wave and self-ignition induced by high-pressure hydrogen release via three 90° arc-shaped tubes. The pressure profiles, photoelectric signals and jet flame were recorded. It was found that reflected shock waves generated in the bend would spread both upstream and downstream. And the reflected shock wave propagating downstream can enhance the intensity of the leading shock wave. But the velocity of leading shock wave in the bend decreased faster than that in the straight part. In addition, based on numerous experiments, two processes of self-ignition in the 90° arc-shaped tube were summarized. One was only affected by the strong leading shock wave, the other was affected by the combination of reflected shock wave and leading shock wave. Moreover, the distance from the bend to the burst disc had an effect on the self-ignition. When the distance from the bend to the burst disc was the shortest, it was least likely to cause self-ignition. Besides, the phenomena of flame quenching cannot occur in the bend of arc-shaped tube. The development characteristics of the external flame was studied, including the flame morphology near the Mach disk and the variation in the size of the jet flame. [ABSTRACT FROM AUTHOR]

Homogeneous charge compression ignition (HCCI) is considered an advanced combustion method for internal combustion engines that offers simultaneous reductions in oxides of nitrogen (NOx) emissions and increased fuel efficiency. The present study examines the influence of intake air temperature (IAT) and premixed diesel fuel on fuel self-ignition characteristics in a light-duty compression ignition engine. Partial HCCI was achieved by port injection of the diesel fuel through air-assisted injection while sustaining direct diesel fuel injection into the cylinder for initiating combustion. The self-ignition of diesel fuel under such a set-up was studied with variations in premixed ratios (0–0.60) and inlet temperatures (40–100 °C) under a constant 1600 rpm engine speed with 20 Nm load. Variations in performance, emissions and combustion characteristics with premixed fuel and inlet air heating were analysed in comparison with those recorded without. Heat release rate profiles determined from recorded in-cylinder pressure depicted evident multiple-stage ignitions (up to three-stage ignition in several cases) in this study. Compared with the premixed ratio, the inlet air temperature had a greater effect on low-temperature reaction and HCCI combustion timing. Nonetheless, an increase in the premixed ratio was found to be influential in reducing nitric oxides emissions. [ABSTRACT FROM AUTHOR]

The fire safety issue of Lithium-ion (Li-ion) batteries is an important obstacle for its market growth and applications. Although the open-circuit condition (e.g. storage, transport and disposal) accounts for the major part of battery lifespan, little research has investigated its self-ignition hazard during non-operating periods. In this work, we experimentally study the self-heating behavior of piled pouch Li-ion battery cells through the classical hot-plate experiments. Results show that the self-ignition of battery pile occurs under a hot plate temperature ranging from 199 °C to 265 °C, depending on the number of cells and environmental cooling. Thermal runaway always first occurs to the cell next to the hot plate and then propagates to upper cells. This critical temperature is increased by 20 °C under a good environmental cooling condition whereas it is reduced by 40 °C as the state of charge increases from 30% to 80%. Moreover, the critical plate temperature for self-ignition increases slightly with the height of battery pile, which is opposite to both hot-plate experiments of hydrocarbon materials and the oven experiments of battery. Therefore, the classical self-ignition theory may not be applicable for Li-ion batteries next to a hot boundary. This research reveals new self-ignition phenomena and helps understand the fire safety of Li-ion batteries in storage and transport. • Study self-ignition of open-circuit pouch Li-ion battery via the classical hot-plate test. • Critical boundary temperature for thermal runaway increases with battery pile thickness. • Insulated boundary reduces the self-ignition temperature of the battery pile by 20 K. [ABSTRACT FROM AUTHOR]

• 3GW th Class Free Force Helical Reactor (3 G Wth FFHR) plant : Regarding the required energy for plasma stability and combustion control, while the tokamak reactor requires additional steady-state energy input for plasma current drive, etc., the helical reactor without the threat of plasma disruption does not require it. • Bypass control type supercritical CO 2 gas turbine power generation system with axial flow type single axis rotating shaft : World's smallest supercritical CO 2 gas turbine power generation system with high thermal efficiency of 45 % or more and low construction cost. • Highly versatile supercritical CO 2 gas turbine power generation system : It can be applied to high-temperature heat sources above 500 ℃ such as fusion reactors, high-temperature geothermal heat, solar heat, and gas turbine exhaust heat. • Highly commercial supercritical CO 2 gas turbine power generation system: It can meet the large-scale power demand conditions (50−60 Hz) in Japan. • Easy maintenance supercritical CO 2 gas turbine power generation system : Space saving and ultra-miniaturization due to vertical placement, etc., and the inspection period is shortened because the number of small parts makes it easy to carry during maintenance. In order to achieve high power generation efficiency, facility compactness, high safety, and high coexistence with fuel tritium in the 3 G W th class FFHR(Force Free Helical Reactor) power plant, optimization, performance and operation scenario of the power generation system of the power plant model using the axial flow type uniaxial supercritical CO 2 gas turbine power generation system were examined. As a result, the following conclusions were obtained. (1) The most efficient and compact axial flow uniaxial design supercritical CO 2 gas turbine power generation system suitable for 3 G W th FFHR power plant has a maximum heat capacity of 1.5GW th ×2, and the gas turbine conversion rate at that time was evaluated as 46.9 %(= 1,267MWe/2,700MW th). Therefore, split connection with two power generation systems is optimal for a 3 G W th class FFHR power plant. Here, the operating speed of the turbo equipment was set to 3600 rpm in order to adapt this plant model to the power supply system in Japan. (2) Simultaneous supply of 818MWe/300 s electricity and 300MW th /30days heat is required at startup of the FFHR. (3) The in-house power during steady operation under the self-ignition condition was reduced to about 31.7MWe, and the amount of power generated at the transmission end was evaluated as 1,234MWe. [ABSTRACT FROM AUTHOR]

Abstract: In the present note we consider the two simultaneous mechanisms that are dominated by gas-phase reactions, namely the upper and intermediate explosion limits, and show that by employing the Le-Chatelier rule, a unified explosion limit is obtained in the form of a single analytical expression. [Copyright &y& Elsevier]

• The moisture absorption ratios of the pretreated products were all lower than 3.8%. • The moisture absorption proneness of pretreated products was obviously inhibited. • The cumulative released heat of extract below 300 °C was 887 kJ/kg lower than RS. • The released heat of biochar and hydrochar below 300 °C was 1000 kJ/kg higher than RS. • The influence mechanism of the three pretreatment methods was elucidated in depth. Three main pretreatment methods (torrefaction, hydrothermal carbonization and degradative solvent extraction) have been developed to deoxygenate and upgrade biomass into biochar, hydrochar and extract, respectively, which have a variety of high-value applications. However, the influence of the three pretreatment methods on the moisture absorption and self-ignition characteristics of biomass still remains unclear, which greatly affects the subsequent storage, transportation and utilization process of the biochar, hydrochar and extract. Therefore, the effects of torrefaction, hydrothermal carbonization and degradative solvent extraction on the moisture absorption and self-ignition characteristics of biomass were investigated and compared in this study. The results showed that the moisture absorption ratios of the pretreated products (biochar, hydrochar and extract) were as low as 3.8%, 1% and 0.8%, respectively, which was obviously lower than that of RS (8%), indicating that the moisture absorption propensities of biochar, hydrochar and extract were all obviously inhibited compared to RS. These results were caused by the dramatic removal of oxygen functional groups during the three pretreatment processes. The heat release of biochar (6950 kJ/kg) and hydrochar (7134 kJ/kg) below 300 °C were obviously higher than that of RS (5950 kJ/kg), while the heat release of extract (5063 kJ/kg) below 300 °C was much lower than that of RS. Compared with RS, biochar and hydrochar had higher specific surface areas and higher contents of inorganic metallic elements, which contributed to their higher self-ignition susceptibilities than those of RS. In contrast, the extract had a dense structure and extremely low oxygen functional groups contents as well as low inorganic metallic elements contents, which jointly led to its lower self-ignition susceptibility than that of RS. This research is expected to provide a comprehensive understanding of the influence mechanism of pretreatment on the moisture absorption and self-ignition characteristics of biomass. [ABSTRACT FROM AUTHOR]

• The critical pressure for ignition increases with methane addition concentration. • Methane addition can effectively inhibit flame development in the tube. • Three mechanisms of self-ignition for hydrogen with methane addition is proposed. • Hydrogen-methane flame spouting from tube exit tends to blow out. • The hydrogen-methane mixture brings greater combustion overpressure in chamber. In this paper, experimental investigations are carried out to study the effects of methane addition (2.5%, 5% and 7.5% vol.) on self-ignition and subsequent flame propagation of pressurized hydrogen release via a tube. The visualization method utilizing the high-speed direct photography and the measurements of pressure and light sensors are applied in this study. The result shows that the existence of methane can reduce the shock wave overpressure and the temperature of shock-heated air. Therefore, it has great effects on the self-ignition possibility. The minimum burst pressure required for self-ignition increases from 2.89 MPa (0% CH 4) up to 6.05 MPa (7.5% CH 4). Besides, methane addition can extremely reduce flame intensity and inhibit flame development inside the tube. Three possible self-ignition mechanisms for the hydrogen with methane addition are discussed. Under the effects of methane addition, hydrogen flame spouting from tube exit tends to blow out. In all cases with 7.5% methane addition, no self-sustained jet flame is formed outside the tube for burst pressure up to 10.0 MPa. When self-sustained flame is formed in a confined space, a great rise in overpressure is generated due to the intense combustion. It is suggested that more methane addition can reduce the self-ignition probability and the formation of self-sustained flame. However, with the increasing of CH 4 additions, once the jet fire is formed in a confined space, it may cause greater overpressure and thus bring greater casualties and property losses. [ABSTRACT FROM AUTHOR]

The processes of hard coal extraction and processing are accompanied by the generation of a considerable amount of post-mining extractive waste, which in most cases is deposited on the ground surface. In the past, such waste was disposed of by deposition in bings and spoil piles of various kinds. The application of modern technologies makes it possible to recycle, reuse or reclaim extractive waste in engineering works or as a substitute of natural aggregates used for the construction of different kinds of banks and embankments. Regardless of whether the waste is deposited or reused, the basic target method of waste management consists of depositing it on the ground surface. This form of extractive waste management is always associated with the risk of the occurrence of coal self-heating phenomena, which may consequently lead to an endogenous fire. Therefore, it is of critical importance to apply appropriate technologies for the construction of coal waste embankments on the one hand, and on the other hand to recognize the mechanisms responsible for the occurrence of fires in extractive waste dumps, which constitutes the subject matter of this paper. [ABSTRACT FROM AUTHOR]

Suicides involving more than one suicide method are termed "complex suicides" and need to be differentiated from murders. Self-immolation is the action of setting fire to oneself and is an infrequent method of suicide method in Western countries. However, burned corpses must be carefully examined because setting fire to a body after death can be a way of covering up a crime. Complex suicides involving self-immolation are rare, but careful analysis is necessary if we are to identify the manner of death. A systematic search of the literature concerning self-incineration in cases of complex suicides was carried out. This covered the age, gender and psychiatric condition of the victims, any history of previous suicide attempts, the existence of suicide notes, evidence of fire accelerants, signs of vital exposure to the fire, toxicology, the other suicide methods used in combination with burning and the characteristics of the burns. 46 cases were found in 22 papers published since 1985, but few of these studies provide any detailed analysis and in several cases many important data were missing. There is, therefore, a need to study this topic and to use an approach based on careful examination of the corpse, detailed investigation of the scene, toxicological examination and an evaluation of the victim's physical and psychiatric state. [ABSTRACT FROM AUTHOR]