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Slab expansion (SLABEX) tests are conducted to validate a process for calibrating the detonation products equation of state (EOS) of a high explosive (HE). The SLABEX tests use rectangular slabs of PBX 9502, a polymer-bonded HE formulation consisting of 95 wt.% 1,3,5-triamino-2,4,6-trinitrobenzene bound with Kel F-800, a co-polymer of chlorotrifluoroethylene and vinylidene-fluoride. Three PBX 9502 slab thicknesses are examined, each confined symmetrically by two rectangular copper (Cu) plates approximately one-tenth the thickness of the HE slab. For the duration of each experiment, the detonation flow along the central axis of the PBX 9502 slab remains two-dimensional. The lateral flow velocity component of the outer surfaces of the expanding Cu plates is measured, along with the steady axial detonation speed along the central axis of the SLABEX. Hydrodynamic simulations of the Cu plate expansion in the SLABEX geometry, driven by the energy stored in the detonation products by the detonation combustion event, are conducted using a Jones–Wilkins–Lee EOS for the detonation products. This EOS form was recently parameterized for PBX 9502 in the cylinder expansion test geometry using a newly developed calibration technique [Voelkel et al., Combust. Flame 246, 112373 (2022)]. Good agreement between the experiment and prediction is found in each SLABEX test, demonstrating that the detonation product EOS calibration technique produces EOSs that are predictive when applied to other geometries. [ABSTRACT FROM AUTHOR]

Snow cover is a good indicator of air pollution and accumulates trace elements and organic pollutants. At the same time, the analysis of snow cover is simple and allows you to assess the presence of these pollutants in the atmosphere. We have studied the snow cover of an urban agglomeration located in the northern part of Europe, with a large number of inhabitants, and therefore with a large anthropogenic load on the atmosphere. We have identified trace elements in the snow cover at many city crossroads. Also we determined the presence of PAHs as the main organic pollutants that are typical for urban agglomerations. Inorganic pollutants were detected in all samples. We found that trace elements contamination advised 1 to 5 according to Nemerow index (PiNemerow). In 50% of the samples, the contamination index corresponded to type V (heavy pollution); 30% to type III and 20% to type IV, respectively. We also determined PAHs in the same places. We can conclude that the values of the investigated substances are low throughout the city. About half of PAHs come from the combustion of wood, the other from the combustion of petroleum products. Since different sources prevail at different sampling points, therefore, it can be assumed about anthropogenic sources, which is also confirmed by the HMW/LMW ratio. No correlations we were found between heavy PAH and Trace elements, no associations were found. [ABSTRACT FROM AUTHOR]

Hydrogen is considered as one of the key energy carrier for the forthcoming green transition because of its high energy content and harmless combustion products. Water electrolysis, powered by green electricity, is one of the most efficient and promising technologies for H 2 production. Cheap and earth abundant metals-based electrocatalysts for Hydrogen Evolution Reaction (HER) are needed to drive a green transition based on hydrogen produced by water electrolysis. Perforated plate type Ni electrodes are prepared by a cost-effective electroforming process, designed to work for water electrolysis in alkaline environment in a flow-through configuration facilitating the release of bubbles produced by HER. The aim of this work is to synthesize a catalyst layer based on NiCuMo alloy produced by an electrodeposition process tailored to maximize electrocatalytic performances, increasing the electrochemical surface active area (more than 50 times) and its activity. HER is studied in aqueous 1 M KOH solution and an overpotential of only 95 mV is measured to reach 100 mA cm−2, assessing a Tafel slope of 61 mV dec−1. 100 h durability test is successfully carried out demonstrating the high chemical and mechanical stability of so-prepared electrodes for next generation alkaline electrolyzers. • PGM-free electrocatalyst is prepared by one-step electrodeposition • High electrocatalytic activity with low overpotential values for HER is assessed • Flow-through configuration is used to mimic industrial electrolyzer • Exceptional electrocatalyst stability, up to 100 h, is demonstrated [ABSTRACT FROM AUTHOR]

Accurately predicting the thermal characteristics and heat transfer distribution of the rotating detonation engine (RDE) and acquiring a clear understanding of the performance and mechanism of the rotating detonation are of great significance for achieving the safe and reliable long-duration operation of RDEs. Using RP-3 as fuel, a long-duration experimental study is performed on a 220 mm-diameter RDC to investigate the details with respect to the thermal environment. The heat flux at the typical location and the average heat flux of both the inner and outer cylinders are measured, respectively. Meanwhile, the peak pressure of the rotating detonation wave (RDW) and specific thrust are analyzed. When the ER is between 0.5 and 1 (oxidizer 2 kg/s), the stable rotating detonation mode is obtained, and the detonation duration is set as 40 s to accurately calculate the heat released by the detonation combustion. The heat flux in the upstream region of the RDW location ranges from 2.40 × 105 W/m2 to 3.17 × 105 W/m2, and the heat flux in the downstream area of the RDW location ranges from 1.05 × 106 W/m2 to 1.28 × 106 W/m2. The results demonstrate the important role of the detonation combustion zone, and the thrust performance of RDC can be improved by making the RDW move forward along the RDC axis, which is the optimal direction of detonation combustion. Through a comparison of average heat flux under different conditions, it is found that the heat released by the RDC is directly related to its thrust. In addition, the average heat flux of the inner cylinder is about three times that of the outer cylinder for the two-phase RDC with a Tesla valve intake structure, indicating that the high-temperature combustion product is closer to the inner wall. Therefore, more thermal protection should be allocated to the inner cylinder, and a more systematic analysis of the two-phase flow field distribution in the annular combustion chamber should be carried out to improve the thrust performance. In this paper, the average heat flux of the inner and outer cylinders of the RDC as well as the typical local heat flux of the outer cylinders is quantitatively measured by means of experiments, which not only deepens the understanding of RDC flow field distribution, but also provides quantitative boundary conditions for the thermal protection design of RDCs. [ABSTRACT FROM AUTHOR]

To improve the thermal and combustion properties of nanothermites, a design theory of changing the state of matter and structural state of the reactants during reaction was proposed. The Al/MoO3/KClO4 (Kp) nanothermite was prepared and the Al/MoO3 nanothermite was used as a control. SEM and XRD were used to characterize the nanothermites; DSC was used to test thermal properties; and constant volume and open combustion tests were performed to examine their combustion performance. Phase and morphology characterization of the combustion products were performed to reveal the mechanism of the aluminothermic reaction. The results show that the Al/MoO3/Kp nanothermite exhibited excellent thermal properties, with a total heat release of 1976 J·g− 1, increasing by approximately 33% of 1486 J·g− 1 of the Al/MoO3 nanothermite, and activation energy of 269.66 kJ·mol− 1, which demonstrated higher stability than the Al/MoO3 nanothermite (205.64 kJ·mol− 1). During the combustion test, the peak pressure of the Al/MoO3/Kp nanothermite was 0.751 MPa, and the average pressure rise rate was 25.03 MPa·s− 1, much higher than 0.188 MPa and 6.27 MPa·s− 1 of the Al/MoO3 nanothermite. The combustion products of Al/MoO3 nanothermite were Al2O3, MoO, and Mo, indicating insufficient combustion and incomplete reaction, whereas, the combustion products of Al/MoO3/Kp nanothermite were Al2O3, MoO, and KCl, indicating complete reaction. Their "coral-like" morphology was the effect of reactants solidifying after melting during the combustion process. The characterization of reactants and pressure test during combustion reveals the three stages of aluminothermic reaction in thermites. The excellent thermal and combustion performance of Al/MoO3/Kp nanothermite is attributed to the melt and decomposition of Kp into O2 in the third stage. This study provides new ideas and guidance for the design of high-performance nanothermites. [ABSTRACT FROM AUTHOR]

Understanding the potential effects of climate change on forest fire behavior and the resulting release of combustion products is critical for effective mitigation strategies in Greece. This study utilizes data from the MAGICC 2.4 (Model for the Assessment of Greenhouse Gas-Induced Climate Change) climate model and the SCENGEN 2.4 (SCENarioGENerator) database to assess these impacts. By manipulating various model parameters such as climate sensitivity, scenario, time period, and global climate models (GCMs) within the SCENGEN 2.4 database, we analyzed climatic trends affecting forest fire generation and evolution. The results reveal complex and nuanced findings, indicating a need for further investigation. Case studies are conducted using the FARSITE 4 (Fire Area Simulator) model, incorporating meteorological changes derived from climate trends. Simulations of two fires in East Attica, accounting for different fuel and meteorological conditions, demonstrate an increase in the rate of combustion product release. This underscores the influence of changing meteorological parameters on forest fire dynamics and highlights the importance of proactive measures to mitigate future risks. Our findings emphasize the urgency of addressing climate change impacts on wildfire behavior to safeguard environmental and public health in Greece. [ABSTRACT FROM AUTHOR]

Gallium (Ga) and germanium (Ge) critical elements have a wide range of applications and market value. Extracting critical elements from coal gangue and combustion products can alleviate pressures on primary mining resources. Understanding the transformation behavior of Ga and Ge during coal gangue combustion processes is significant for resource utilization and environmental protection. Coal gangue from Xing'an League, Inner Mongolia, was chosen to explore how combustion temperatures (600 °C to 1000 °C) and particle sizes (50, 80, 10, 140, and 200 mesh) influence Ga and Ge migration during combustion. Techniques such as ICP-MS, XRD, XRF, SEM, TG-DSC, and sequential chemical extraction were employed to analyze the transformation of minerals and to quantify the contents and occurrence forms of Ga and Ge. Smaller gangue particle sizes were associated with higher concentrations of Ga and Ge. Approximately 99.19% of Ga and Ge in coal gangue were found in the residual, organic/sulfide-bound, and metal-oxide-bound modes. High temperatures promoted element volatilization and changed the reactions and interactions between elements and minerals. As combustion temperatures rose from 600 °C to 1000 °C, Ga and Ge contents in the products declined progressively. Under high temperatures, minerals like kaolinite, illite, and pyrite in gangue converted to silicate glass phases, mullite, and hematite. Minerals like kaolinite, calcite, and pyrite melted, leading to increased cohesion and agglomeration in the products. Over 90% of Ga and Ge in the combustion products existed in the residual, organic/sulfide-bound, and metal-oxide-bound forms. Moreover, Ga was enriched in combustion products, with its content exceeding critical extraction levels. The results may provide a useful reference for developing critical elements enrichment, extraction, and separation technologies from coal gangue. [ABSTRACT FROM AUTHOR]

Large and downed woody fuels remaining behind a wildfire's flame front tend to burn in a smoldering regime, producing large quantities of toxic gases and particulate emissions, which deteriorates air quality and compromises human health. Smoldering burning rates are affected by fuel type and size, the amount of oxygen reaching the surface, and heat losses to the surroundings. An external wind has the dual effects of bringing fresh oxidizer to the fuel surface and porous interior, while at the same time enhancing convective cooling. In this work, a series of experiments were conducted on single and adjacent poplar dowels to investigate the effect of fuel geometry and wind speed on smoldering of woody fuels, including its burning rate and combustion products. Dowels had variable thickness (19.1 and 25.4 mm), aspect ratios, and arrangement (number of dowels and spacing between them). Using measurement of mass loss, CO, and HC production as indicators of the smoldering intensity, the results indicate that the arrangement of smoldering objects significantly affects burning rates and emissions. Specifically, spacings of 1/8 and 1/4 of the dowel thickness enhanced the smoldering process. The smoldering intensity was also enhanced by increased external wind (ranging between 0.3 m/s and 1.5 m/s), but its effect was dependent upon the spacing between the dowels. The convective losses associated with the spacing were further investigated with a simplified computational model. The simulations show that the wind significantly increases convective losses from the smoldering surfaces, which in turn may offset the increase in smoldering intensity related to the higher oxygen flux at higher wind speeds. [ABSTRACT FROM AUTHOR]

Wildfires result in the emission of large volumes of toxic smoke, which is transported hundreds of kilometers away from the fires and can have an adverse impact on soil, biota, and humans. A series of modelling experiments on pyrogenic fumigation of soil has been carried out to assess the effects of gaseous products of wildfires on soil biochemical parameters. The effects of continuous exposure to gaseous substances and periodical, repetitive effects of smoke exposure on soil have been determined. The results have been compared with a single intense smoke exposure. It was found that pyrogenic impact significantly affected the enzymatic activity of ordinary chernozem. The degree of influence depended on the duration and periodicity of smoke exposure. In all experiments, enzymes of oxidoreductase class (catalase, peroxidase, polyphenol oxidase) were more sensitive to fumigation than invertase from hydrolase class. High concentrations of toxic gases were the cause of suppressed enzymatic activity of soils. The following concentrations exceeded the maximum permissible concentrations for atmospheric air: CO 714 times, phenol (hydroxybenzene) 441 times, acetaldehyde 24100 times, formaldehyde 190 times. Accumulation of polycyclic aromatic hydrocarbons (PAHs) in soil after fumigation was revealed, the total content of PAHs was 377 ng/g. The highest values were recorded for naphthalene, where the concentration was 4.4 times higher than the maximum permissible concentration and phenanthrene, 2.8 times higher than the maximum permissible concentration. It has been found that 60-min intensive smoke affects the soil to a lesser extent than continuous and periodical ones. Indices of enzymatic activity of chernozem after such fumigation decreased by 15–33% depending on the enzyme, and after continuous and periodical by 41–84 and 31–78%, respectively. The obtained data indicated a significant effect of smoke on the enzymatic activity of soils under continuous and periodical exposure to gaseous products of combustion. [ABSTRACT FROM AUTHOR]

Environmental and work safety aspects necessitate a radical change in the foundry industry. Organic binder systems for foundry sand cores create toxic combustion products and are, therefore, more and more often substituted by inorganic binder systems. While providing an environmental advantage by mainly releasing water vapor, inorganic binder systems impose new challenges for the casting process. The gas release of inorganically-bound foundry cores can lead to increased gas porosity in the cast parts and thus to high scrap rates. The present work aims to gain more understanding of the gas generation and transport in inorganic sand binder systems. We developed a test stand to measure the temperature-dependent core gas release in inorganically-bound foundry cores and their gas permeability. Samples were prepared in a core blowing process and analyzed using the test stand. The measurement results are in good agreement with validation experiments and existing literature. [ABSTRACT FROM AUTHOR]

[Display omitted] • Co-incineration biodried products in cement kilns were researched. • Combustion performance of biodried products was better than that of sewage sludge. • Heat efficiency of biodried products during co-incineration was 93.7%. • Co-incineration leads to increased SO 2 and NO X emission concentrations. • Biodried product as fuels have greater potential to reduce carbon emissions. The biodrying technology as a pretreatment technology can overcome the limitations of cement kilns co-incineration sewage sludge (SS) on energy consumption. But the impact of SS biodried products on cement kilns and the route carbon reduction potential of biodrying + cement kilns have not been studied. In this study, SS biodrying and cement kiln co-incineration biodried product trials were conducted to highlight the matrix combustion characteristics, and the impact of biodried products on cement kilns (clinker capacity, coal consumption, and pollutant discharge). The carbon emissions of the four scenarios were assessed based on these results. The results showed that water removal rate reached 65.5 % after 11-day biodrying, and the wet-based lower heating value of the biodried product increased by 76.0 % compared with the initial matrix. Comprehensive combustibility index of the biodried product (0.745 × 10−7 %2℃−3min−2) was better than that of SS (0.433 × 10−7 %2℃−3min−2) although a portion of the organic matter was degraded. Cement kiln co-incineration of biodried products (150 t/d) resulted in per tonne of clinker saved 5.61 kg of coal due to the heat utilization efficiency of biodried products reached to 93.7 %. However, it led to an increase in the emission concentrations of NO X and SO 2. Assessment results indicated that the biodrying + cement kiln pathway reduced CO 2 emissions by 385.7 kg/t SS. Biodried products have greater potential to reduce emissions as alternative fuels than as fertilizers. This study indicated the advantages of SS biodrying + cement kiln co-incineration route. [ABSTRACT FROM AUTHOR]

This work focused on the production of the MoAlB MAB phase through self-propagating, high-temperature synthesis in the thermal explosion mode. The influence of the method of a Mo-Al-B-powder reaction mixture preparation on the combustion temperature, mechanism, and stages of the MAB phase formation in the combustion process was investigated. The combustion temperatures of the mixtures obtained in the rotary ball mill and high-speed planetary ball mill were 1234 and 992 °C, respectively. The formation of intermediate compounds Mo3Al8 and α-MoB in the combustion front, along with MoAlB, was established using the time-resolved X-ray diffraction method. In the case of the mixture prepared in a ball mill, the primary interaction in the combustion front occurred through the Al melt, and in the case of using a planetary mill, solid-phase reactions played an important role. The mechanical activation of the mixture in a planetary mill also accelerated the processes of phase formation. The method of a reaction mixture preparation has virtually no effect on the MoAlB MAB phase content in combustion products (92–94%), but it does affect their structure. The synthesis products have a lamellar structure composed of MAB grains with a thickness of ~0.4 μm and a length of ~2–10 μm. [ABSTRACT FROM AUTHOR]

Combustion is often accompanied by environmental pollution due to incomplete reaction. A non-excited flame usually exhibits poor combustion performance with features of diffusion flame such as dual-peak temperature distributions and large combustion product concentrations. Efficient fuel-air mixing has been identified as a key factor in mitigating this issue. The present study investigated the effects of the acoustic excitation Strouhal number on the combustion performance of a backward-inclined jet flame in crossflow. A loudspeaker was used to induce jet pulsations with excitation Strouhal numbers ranging from 0.47 to 1.54 at a pulsation intensity of 0.90. Time-averaged and instantaneous flame images were captured using digital cameras. A customized R-type thermocouple and a commercial gas analyzer were employed to analyze the thermochemical structures. A critical excitation Strouhal number of approximately 0.9, distinguishing two characteristic flame modes: strongly affected flame (SA flame) and weakly affected flame (WA flame), was found. At excitation Strouhal numbers lower than the critical value, the SA flame featured single-peak temperature profiles and low unburned hydrocarbon, carbon monoxide, and nitric oxide emissions. The combustion performance was significantly improved due to the strong mixing effect induced by the acoustic excitation. The WA flame appeared at excitation Strouhal numbers higher than the critical value. It exhibited dual-peak temperature distributions and slightly improved combustion performance. The dynamic behavior and emissions of acoustically excited jet flames offered a fascinating insight into the influence of excitation Strouhal numbers on combustion characteristics. More excitation conditions were expected for future research. [ABSTRACT FROM AUTHOR]

The contents of 49 trace elements in sub-bituminous Pernik coals and their waste products from preparation and combustion processes were investigated. The studied coals have trace element contents higher than the respective Clarke values for brown coals and some of them may pose environmental concerns. The elements Li, Rb, Cs, Ba, Sc, Y, La, Ce, Nd, Sm, Eu, Er, Ga, Zr, Sn, V, Nb, Ta, W, F, Cu, Zn, In, Pb, Cr, Co, Ni, and Th in the feed coals have concentrations that exceed twice the Clarke values. Most element contents in bottom ash are enriched compared with those in feed coal. Some of the volatile elements are equal or significantly depleted including Sn, Mo, Sb, F, Bi, Cd, Ge, and Pb. Fly ash has higher contents of Ga, Zr, Hf, Sn, V, Nb, Mo, and F in comparison with bottom ash. Most elements have a significant positive correlation with ash yield, indicating their inorganic association. The mixed wastes (coal slurry, bottom ash, and fly ash) in the disposal pond are slightly depleted of most of the elements studied with the exclusion of Cl, Ba, and Br. The Pernik coals and their waste products are unpromising for the extraction of REY due to their low element contents. [ABSTRACT FROM AUTHOR]

Polyurethane (PUR), as an engineering polymer, is widely used in many sectors of industries. However, the high fire risks associated with PUR, including the smoke density, a high heat release rate, and the toxicity of combustion products limit its applications in many fields. This paper presents the influence of silsesquioxane fillers, alone and in a synergistic system with halogen-free flame-retardant compounds, on reducing the fire hazard of polyurethane foams. The flammability of PUR composites was determined with the use of a pyrolysis combustion flow calorimeter (PCFC) and a cone calorimeter. The flammability results were supplemented with smoke emission values obtained with the use of a smoke density chamber (SDC) and toxicometric indexes. Toxicometric indexes were determined with the use of an innovative method consisting of a thermo-balance connected to a gas analyzer with the use of a heated transfer line. The obtained test results clearly indicate that the used silsesquioxane compounds, especially in combination with organic phosphorus compounds, reduced the fire risk, as expressed by parameters such as the maximum heat release rate (HRRmax), the total heat release rate (THR), and the maximum smoke density (SDmax). The flame-retardant non-halogen system also reduced the amounts of toxic gases emitted during the decomposition of PUR, especially NOx, HCN, NH3, CO and CO2. According to the literature review, complex studies on the fire hazard of a system of POSS–phosphorus compounds in the PUR matrix have not been published yet. This article presents the complex results of studies, indicating that the POSS–phosphorous compound system can be treated as an alternative to toxic halogen flame-retardant compounds in order to decrease the fire hazard of PUR foam. [ABSTRACT FROM AUTHOR]

The article presents experimental research and calculations of spark ignition engine indicators, using hydrogen-containing H 2 /O 2 gas, when the engine is running at low power. The engine throttle was opened 8°, the amount of H 2 /O 2 gas was increased from 0 to 7.9 % of the mass of gasoline, the stoichiometric (λ = 1) air/fuel ratio was maintained. Research shows that the addition of the H 2 /O 2 gas leads a great influence on the energetic and ecologic indicators of the engine and this depends on the change in the combustion process and the change in the composition of the fuel. The calculation methodology of the combustion process when the engine is fuelled with pure gasoline and with additives of hydrogen-containing gas presented. Presented results how addition of H 2 /O 2 leads to a reduction in the duration of the combustion process and also has a significant effect on a faster rise of combustion pressure and temperature. Shorter combustion duration leads to a rise of the indicated efficiency of the engine, the heat utilisation factor and an increase in the indicated power. As a result of bench tests, an increase in the effective power and a decrease in the brake-specific fuel consumption of the engine were found. When assessing the influence of H 2 /O 2 on the concentration of CO 2 in the exhaust gas, no decreases was not observed, as hydrogen improves the combustion process. Only the concentration of incomplete combustion process products (e.g., HC) decreases, but the concentration of NO x increases at the same time. • Study of indicators of the engine operating at low power by changing the amount of H 2 /O 2 in a wide range. • Described method for calculating the indicated engine parameters, taking into account the addition of H 2 /O 2. • Determined indicators of the combustion process for the gasoline engine operating with the H2/O2 additive. • The addition of an H2/O2 (7.9% of mass) enhances heat usage efficiency and raises the indicated efficiency to 13.9%. • The H 2 /O 2 additive reduces BSFC but does not significantly affect the CO 2 emissions of the SI engine. [ABSTRACT FROM AUTHOR]

In the course of Russia's war on Ukraine, fierce forest fires, burning of oil and ammunition depots and destruction of urban and industrial areas have spread hazardous combustion products far and wide and are accelerating global heating. Measures to stabilise the national environmental situation, and to prevent a larger-scale ecological disaster, should combine the efforts of managerial, regulatory and practical efforts, with priority given to preventive measures. There is need for improved methodology for assessing environmental loss and damage, as well as the procedures to bring the perpetrators to justice. In the absence of a unified national system of monitoring air quality, we consider the opportunities for adopting an effective monitoring system. [ABSTRACT FROM AUTHOR]

The possibility of obtaining a composite material from a ferroalloy based on silicon, aluminum, and zirconium nitrides using self-propagating high-temperature synthesis is considered. It is shown that introducing up to 35% of a nitrogen-containing additive on the basis of ferroalumosilicozirconium to the initial ferroalloy leads to an increase in the nitrogen fraction, emission of the basic nitride phases in combustion products, deceleration of the combustion wave front, and reduction of the maximum combustion temperature. It is revealed that adding more than 20% of a preliminary nitrided material makes it possible to stabilize the combustion wave front propagation conditions and to obtain combustion products with a macroscopically homogeneous composition. Under the conditions of natural filtration of nitrogen, combustion of a powder mixture based on ferroalumosilicozirconium and a nitrided material yields a composite consisting of AlN, Si3N4, ZrN, and -Fe phases. [ABSTRACT FROM AUTHOR]

Targeted synthesis of oxynitride composites is implemented by means of organizing coupled processes. Interaction of ferrosilicon with nitrogen during combustion is considered as the main (inducing) process. The phase composition of the products of the coupled processes is determined by the chemical and phase compositions of the components added to ferrosilicon before performing self-propagating high-temperature synthesis. The influence of the basic products of the synthesis on the burning rate, fraction of nitrogen, phase composition, and morphology of synthesis products is considered. Chemical stages of ferrosilicon interaction with additives of natural minerals (zircon, ilmenite, and shungite) and aluminum in a nitrogen medium are demonstrated. The phase composition is determined by chemical transformations in a combustion wave. It is found that addition of aluminum leads to reduction or elimination of the Si2N2O phase in synthesis products with an increase in the aluminum fraction and obtaining composites based on the Si3N4 (SiAlON) solid solution. The microstructure of combustion products is presented by aggregates (5–10 m) composed of small faceted crystals, shapeless structures, and crystal flakes. Oxynitride composites with an open porosity value of 51.0–68.8% are obtained. [ABSTRACT FROM AUTHOR]

Organometallic complexes of transition metals with inorganic anions are considered as promising precursors for the synthesis of nanoscale materials used in various applications including chemical catalysis. In this work, organometallic complexes of nickel, iron, and copper with imidazole as an organic ligand and the nitrate anion as an inorganic ligand were synthesized and characterized. The kinetic parameters of thermal decomposition of the synthesized organometallic complexes were determined by low heating-rate thermogravimetric analysis and high-speed dynamic mass spectrometric thermal analysis. The main gaseous products of thermal decomposition of the complexes under high-speed heating were identified. The chemical and phase compositions of condensed combustion products of the organometallic complexes in air were studied. [ABSTRACT FROM AUTHOR]

• Trona ash leachate (TAL) has high ionic strength among coal combustion leachates. • Hydraulic conductivity to TAL is high at low GCL mass per unit area (MPUA). • Hydraulic conductivity to TAL is low at MPUA of 5.0 kg/m2. • Bundles of fibers play an important role on hydraulic conductivity at low MPUAs. The barrier performance of geosynthetic clay liners (GCLs) to coal combustion products (CCPs) is of primary importance. One of the CCPs leachates that has a damaging effect on hydraulic conductivity is trona ash leachate (TAL). In this study, the hydraulic conductivity of sodium GCL (Na-GCL) to TAL was investigated in terms of mass per unit area (MPUA). The hydraulic conductivity of GCLs to TAL was 2.6 × 10-6 and 7.6 × 10-7 m/s when the MPUA was 3.0 kg/m2 (M b3) and 4.0 kg/m2 (M b4), respectively. Dye tests conducted on these GCLs showed that flow preferentially occurred through bundles of fibers existing in the GCLs. In contrast, increasing the MPUA to 5.0 kg/m2 (M b5) led to a decrease in the hydraulic conductivity (i.e. 4.1 × 10-11 m/s). Additional tests were performed on fiber-free GCLs to determine the role of fiber bundles. Regardless of MPUA, the fiber-free GCLs had low hydraulic conductivity (6.7 × 10-11 m/s). Prehydrating M b3 and M b4 with deionized water (DIW) before permeation with TAL also decreased the hydraulic conductivity. The hydraulic conductivities of prehydrated M b3 and M b4 were 1.6 × 10-10 and 4.8 × 10-11, respectively. Chemical analyses showed that the cation exchange reaction had a negligible influence on the hydraulic conductivity. Because TAL was a potential source of Na+ throughout the tests. [ABSTRACT FROM AUTHOR]

The present study focuses on modeling the solid oxide fuel cell power plant combined with an absorption-ejection refrigeration cycle. First, a comparison is made between the absorption chiller refrigeration cycle and the absorption-ejection chiller to connect the superior cycle to the solid oxide fuel cell as an auxiliary cycle. Then, the solid oxide fuel cell cycle, the combustion of the output product, the heat recovery unit combined with the refrigeration cycle, and freshwater production are modeled. Next, the sensitivity analysis is presented in order to study the effect of the design parameters on objective functions, which simplifies the justification of the optimization results based on the genetic algorithm. In order to perform optimization, machine learning methods have been employed to reduce computational time and cost. The optimization of this cycle shows that the exergy efficiency is enhanced up to 68%, whereas the overall cost rate is in within 9.7–10.4 dollars per hour. • An integrated gSOFC cycle power plant is proposed, modeled, and designed. • A parametric study is conducted to study the effect of design variables. • Using ejector absorption chiller to increase the efficiency. • Optimal design is performed through a multi-objective optimization method. [ABSTRACT FROM AUTHOR]

Flare stacks , used for emergency venting of redundant hydrogen, can cause jet fires that pose thermal hazards to the surrounding environment. To accurately predict the hazard distance of hydrogen flare, it is necessary to develop a new flare radiation model. Also, the numerical simulations of hydrogen flame are carried out to assess the radiation hazard area of the flares. The results show that the hazard distances predicted by the numerical method and the new model agree well with the HSL data fitted by exponential regression, and the errors are less than ±5%. Furthermore, the new model and simulations were used to analyze the distribution of thermal radiation for hydrogen flare under various release conditions. Increasing the release rates will drive the hazard boundary of flare system to expand. Additionally, as flare height increases, the radiation damage from the flare flame on ground is reduced due to buoyancy of combustion products. • A appropriate flare hazard distance can effectively prevent potential thermal hazards. • A new model for predicting the hazard distance of hydrogen flares is developed. • Simulations and the new model improved prediction accuracy of hydrogen flare hazard distance. • The hydrogen flare radiation model was applied to various release conditions. [ABSTRACT FROM AUTHOR]

This article proposes organizational and technical measures to reduce energy consumption of re-heating furnaces section of hot rolling mill 1700 in hot rolling shop No.1 of "ArcelorMittal Temirtau" JSC, such as fuel combustion quality management, performed and presented calculation of energy consumption per unit of production. The industrial experiment was performed there. As it is known, one of the features of re-heating furnaces is the fact that the minimum specific fuel consumption takes place when burning it with the maximum possible pyrometric effect. To solve the research tasks, a fundamentally new 3D model of combustion products motion with the possibility of parameters correction to calculate and optimize the energy-efficient operation of the furnace was applied. Experimental data were obtained on high-precision stationary and portable equipment, metering devices passed state inspection, which excludes the unreliability of the data obtained. [ABSTRACT FROM AUTHOR]

The present study performs three-dimensional (3D) numerical simulations of coal combustion of four samples with varying ash content in a drop tube furnace (DTF) to mimic the particle heating rates observed in industrial furnaces. The numerical framework adopted is validated with prior experimental and simulation results using a 3D cylindrical geometry and a very good match is obtained for the axial temperature distribution and particle burnout rate. The combustion performance of coal samples with varying ash contents of 2.3, 16.6, 24.1, and 37.2 wt%, is explored through temperature profiles, burnout rates, particle tracking, and mass fractions of various products of combustion. A user-defined function is used to specify the 14 species, 10-step solid particle combustion with a modified eddy dissipation concept model for volatile combustion. The range of ash content considered is for Indian coal which has a high degree of heterogeneity, making the evaluation of its combustion performance, a challenge. The present work aims to provide benchmark set of results showing the evolution of the evaporated, charred, and volatile mass for the three ash contents, which has not been attempted before. It is found that the high-ash content Indian coal samples have a tendency to produce less NOx . A 9:52% reduction in the NOx is obtained for the coal sample with 37:2% ash compared to that with 16:6% ash. The results suggest that the combustion performance is enhanced when the ash content falls within an optimum range of 20 35%. [ABSTRACT FROM AUTHOR]

In this study, a simulation and experiment on laboratory conditions were conducted to investigate the effects of a retrofitted DOC-DPF-SCR system on the performance and pollutants of an in-service old-generation light-duty diesel engine. Simulations demonstrate that DOC and SCR have little effect on engine performance, but the particle filter does. With 220 mm, 240 mm, and 260 mm DPF cores, brake power was reduced by 1.9%, 4.5%, and 12.0% at rate condition and 1.2%, 3.6%, and 10.8% at maximum brake torque condition. The after-treatment system can reduce soot by 64.8% to 81.9% at full load conditions and 55.6% to 83.3% as the load varies at a constant speed. NOx emissions were reduced significantly by an average value of 81.9% at full load and 21.7% to 78.1% at a constant speed, depending on load. The DOC combined with DPF also influenced incomplete combustion products as the concentration of CO and HC decreased by 73.6% and 76.5% on average at full load conditions. Following emission standards, HC and CO emissions were reduced by 63.8% and 68.7%, respectively; NOx and PM were decreased by 71.1% and 76.6% when the engine was retrofitted with the after-treatment system. After retrofitting, the old-generation diesel engine can pass the Euro II standard. [ABSTRACT FROM AUTHOR]

In June 2020, a record-breaking Saharan dust storm, known as the "Godzilla" extreme event, caused significant dust transport from the Sahara Desert across the Atlantic Ocean to the United States. Based on satellite observations, the magnitude of aerosol optical depth (AOD) has consistently remained highest over the Atlantic Ocean for the past 18 years. This study uses satellite observations (including MODIS and CALIOP) and MERRA-2 reanalysis products to investigate the relationships between dust and marine clouds. During this extreme event, the concentration of AOD exhibits a synchronous anomaly with the cloud fraction (CF). Principal components analysis (PCA) results show that the enhanced temperature and specific humidity near the surface contribute the most to cloud development over the tropical Atlantic Ocean. Despite the reduced sensitivity of CF to aerosols, the semi-direct effect of dust can still play a crucial role during this extreme dust storm. We found that the presence of absorbing aerosols above the cloud layers warms the air, accompanied by an enhancement of surface moisture, thereby benefiting low-level cloud coverage. [ABSTRACT FROM AUTHOR]

Moderate or intense low oxygen dilution (MILD) combustion is investigated in a co/counter-swirl using OH∗-chemiluminescence, species measurements, OH planar laser-induced fluorescence (OH-PLIF), two-dimensional particle image velocimetry (2D-PIV), and microphone measurements. Experiments are performed in a two-stage combustor, where the first stage of combustor is catalytic stage and the second stage is the swirl stage (co/counter-swirl configuration). A fuel-rich syngas (20 % H 2 , 20 % CO, 12 % CO 2 , 2 % CH 4, and 46 % N 2) reacts with air in the catalytic stage. Then, the mixture of unconsumed syngas and products of catalytic combustion is supplied to the swirl stage where the mixture is burnt with oxidizer with varied oxygen concentration. The flame in the swirl stage is established by two concentric swirling streams where the inner stream is the hot gases from the catalytic stage, and the outer stream is the oxidizer. Co/counter-swirl flames are generated by changing the swirl direction of the inner stream. After achieving a stable flame, the macrostructure, flame steadiness, CO and NO x emissions, reaction zone distribution, and sound pressure level (SPL) are investigated at several oxygen concentrations (O 2 = 13.13 %–21 %) with an aim to assess the MILD combustion mode in co/counter-swirl configuration. As the oxygen percentage decreases, the flame luminosity decreases for both co/counter-configuration. However, the reduction in luminosity is profound for co-swirl configuration. Clear distinctions between co and counter-swirl configurations are observed regarding flame height and stand-off height. Two-dimensional particle image velocimetry (2D-PIV) is utilized to understand these trends. The steadiness of the flame is investigated using standard deviations (SD) of OH∗-chemiluminescence images and global luminosity (I(t)). The flame steadiness is found to be improved as the oxygen concentration decreases. The OH-PLIF indicates the distributed nature of combustion. The NO x emission is found to be extremely low in all studied cases; however, the CO emission shows an increasing trend when O 2 reduces. Finally, the sound pressure level and the dynamics stability are investigated using microphone measurements. The SPL decreases by ∼3 dB and ∼7 dB for the counter-swirl and co-swirl configuration, respectively. Furthermore, the frequency domain analysis suggests that the fundamental axial mode of the combustor is excited at high oxygen concentration. However, the unsteady combustion and chamber acoustics become decoupled at lower O 2 concentrations. Thus, the present paper, for the first time, confirms that MILD combustion can be achieved in co/counter-swirl configuration, provided the oxygen concentration is low (∼13 %). The present study also establishes that the co-swirl configuration is more suitable than the counter-swirl for achieving the MILD combustion mode. • Moderate or intense low-oxygen dilution (MILD) combustion is achieved in co/counter-swirl configuration. • OH∗ chemiluminescence intensity decreases with O 2 concentration. • High-speed chemiluminescence indicates improved stability at low O 2 concentrations. • Sound pressure level decreases with O 2 concentration, and NO x is below 2 ppm. • PIV and PLIF highlight the difference between co and counter-swirl flames. [ABSTRACT FROM AUTHOR]

This study investigates the ignition and combustion characteristics of interacting hydrogen (H 2) and diesel surrogate jets under simulated compression-ignition engine conditions. The experimental setup includes two converging single-hole injectors in an optically accessible constant-volume combustion chamber (CVCC). The parameters varied in the study are fuel injection durations and ambient O 2 concentrations (10 to 21 vol.%). The results show that a longer interaction between the diesel products and the H 2 jet is required to achieve ignition of the H 2 jet at lower O 2 concentrations. Once ignited, the flame stabilises near or at the nozzle, except under the lowest ambient O 2 condition of 10 vol.% where a lifted flame is observed. The lift-off response, however, is influenced by the relative injection duration of the fuels, with the interaction between the incoming H 2 jet and the diesel combustion recession products possibly playing a role. The interaction between the jets also affects the recorded intensity and the distribution of the diesel fuel jet soot zone. • Parametric study of H 2 -diesel jet combustion in engine-related conditions. • Energy share, via injection duration variation, and ambient O 2 concentration effects studied. • Longer jet–jet interaction required to cause H 2 ignition at lower O 2 ambient. • H 2 jet lift off response dependent on ambient O 2 concentration and jet–jet interaction. • Jet–jet interaction affects the characteristics of the diesel jet soot zone. [ABSTRACT FROM AUTHOR]

Hydrogen has the characteristics of high combustion value, no pollution of combustion products, and high element content, which is considered to be the most advantageous green energy in the future. The mobile hydrogen source can achieve the preparation of hydrogen at any time, effectively avoiding the safety hazards of hydrogen in the storage and transportation process. Magnesium-based active materials, which can release hydrogen by hydrolysis at room temperature, can be ideal materials for mobile hydrogen sources. This article presents a comprehensive review of recent research progress on magnesium-based active materials, focusing on four aspects of magnesium hydrolysis reaction research: preparation methods of magnesium materials, addition of catalysts, reaction media, and applications of active magnesium-based materials. In addition, the promotion mechanism of magnesium hydrolysis reaction for different preparation methods, catalysts, and reaction media is also summarized in detail. Finally, the limitations of the current research on magnesium-based active materials are analyzed, and the future research and application aspects of this material are prospected. [ABSTRACT FROM AUTHOR]

The formation of local areas in large buildings with regulated thermal conditions is an urgent task. The use of gas infrared heaters for this purpose raises questions on the utility of an air-exchange system and the monitoring of the combustion product concentration. In this study, the modeling of heat transfer processes on premises with a gas infrared heater and an air-exchange system was conducted. The carbon dioxide concentration in the local working area when using a light-type gas infrared heater was determined. The regularities of current formation for circulating air and combustion products on the premises at various air-exchange rates were analyzed. The profiles of CO2 temperatures and concentrations in the local working areas on the left and right of the equipment model are shown. The article makes a conclusion about the influence of air velocity from the air-exchange system based on average values of carbon dioxide concentration on the premises and in the local working area. The possibility of increasing the temperature in the local working area without exceeding the permissible CO2 concentrations (less than 1000 ppm) has been identified. The formulated approach allows us to predict the available modes of the air-exchange system to create the highest possible comfort heating parameters while maintaining an acceptable degree of air pollution from combustion products. [ABSTRACT FROM AUTHOR]

A set of eight coals from the premium Argonne coal sample program were studied using thermogravimetric and evolved gas analysis. Gaseous combustion products were analyzed using an FTIR spectrometer and a chemiluminescence analyzer. Additionally, modulated thermogravimetric experiments were carried out to determine activation energies associated with the combustion of each sample. The exhaust from the thermogravimetric analyzer was directed to the gas analyzers for detecting and quantifying CO, CO2, and NO. Evolved gas analysis was conducted at a ramp rate of 5°C for CO, CO2 evolution, and 20°C per minute for nitric oxide evolution, with the furnace temperature varying between 20°C–750°C. Modulated thermogravimetric analysis experiments were carried out in the same temperature range. The temperature was increased at a rate of 2°C per minute for the modulated experiments. Each test had a superposed temperature modulation with amplitude ±5°C and a period of 200 seconds. The experiments provide valuable information on the combustion kinetics and emission characteristics of selected American coals. [ABSTRACT FROM AUTHOR]

The concepts of residual gas and admission (or volumetric efficiency) coefficients are used exclusively by specialists in the field of piston Internal Combustion Engines. However, it is preferable to apply the concepts of volume fractions of components of the working mixture consisting of air, fuel, residual, and recirculating gases, for the evaluation of filling. This simplifies and makes it more easy-to-grasp the influence of individual factors on the results of gas exchange processes. The proposed approach makes it possible to take into account the impact on the engine indicators of the molecular weight of the fuel used and the degree of external recirculation, as well as to reduce the number of independent variables. At the same time, the displacement coefficient A proposed by the author characterizes a decrease in filling when an engine with external mixing is switched to a gaseous fuel with a lower molecular weight. A change in the valve timing made it possible to produce an effect on the composition of the working mixture and, thereby, the environmental characteristics of the engine. In the case of external recirculation, it becomes necessary to estimate the summary fraction of neutral combustion products in the working mixture, on which all engine operation depended. This ”overall degree of recirculation” can also be determined using the proposed approach. [ABSTRACT FROM AUTHOR]

Abstract—The results of a study on the effect of one type of pyrogenic factor (smoke) after burning coniferous wood chips on several bioindicators (soil enzymes, microorganisms, mesofauna, plants of agricultural crops) are presented. Exposure to smoke for 60 minutes was found to affect the enzymatic activity of the common chernozem significantly. Fumigation caused a decrease in enzymes such as catalase, peroxidase, polyphenol oxidase, and invertase. The enzymes of the oxidoreductase class were the most sensitive to smoke. The high toxicity of the gaseous combustion products to the soil flora and fauna was revealed. The acute toxicity of smoke to the bioindicators was determined as a result of fumigation. The high mortality of test objects (Eisenia fetida and Nauphoeta cinerea) was recorded in our experiments. Soil microorganisms (Azotobacter chroococcum and Penicillium chrysogenum) proved to be informative after 30–120 minutes of fumigation. The resistance of plant sprouts (Raphanus sativus, Triticum aestivum, and Pisum sativum) to gaseous combustion products was revealed. An experiment to analyze the chemical composition of gases in smoke was conducted. Hazardous compounds such as sulfur dioxide (SO2), nitrogen oxide and dioxide (NO, NO2), carbon monoxide (CO), acetaldehyde (C2H4O), formaldehyde (CH2O), phenol (C6H6O) hydroxybenzene, and others were found to be contained therein. Our analysis revealed that the concentrations of carbon monoxide were 714 times higher than its maximum permissible concentration (MPC), while that of acetaldehyde was 24 100 times higher. The nitrogen oxide and nitrogen dioxide concentrations were 100 and 300 times higher, respectively. [ABSTRACT FROM AUTHOR]

Artemisia argyi Lévl.et.Vant.is a traditional Chinese medicine in China.Its chemical components mainly include essential oil, flavonoids, phenylpropanoids and terpenoids, etc. It has various pharmacological activities such as antiasthmatic and antitussive, anti-tumor, anti-inflammatory, antibacterial and antiviral, and anti-oxidation.Artemisia argyi is dried and mashed to make argyi. The main components of combustion product of Artemisia argyi are furans, aromatic, esters, alkanes or hydroxyl compounds, which have the functions of anti-fungal and virus, anti-aging and regulating lipid metabolism. This paper reviewed the research progress on the chemical constituents and pharmacological action of Artemisia argyi and its combustion product, in order to provide the basis for the developmen utilization of Artemisia argyi. [ABSTRACT FROM AUTHOR]

The solid solutions of iron and aluminum spinels (hercynite, maghemite, magnetite, and γ-alumina) are promising materials for emerging technologies such as solar thermochemical fuel production and clean dehydrogenation of fossil fuels. Solution combustion synthesis (SCS) is an attractive technique for the fabrication of these materials as it has been used for synthesis of many nanoscale oxides. However, the design space of SCS is large with many synthesis parameters affecting the properties of the combustion products. To optimize the SCS of these materials, it is important to determine which parameters yield the best properties. In the present work, FeAlO x nanocomposites were obtained by SCS using iron nitrate and aluminum nitrate as precursors and oxidizers. Two fuels (citric acid and glycine), three Fe:Al molar ratios (1:2, 1:1, and 2:1) in the precursors, and three heating modes (hotplate, muffle furnace, and microwave oven) were compared. The products were characterized by X-ray diffraction analysis, scanning electron microscopy, Brunauer-Emmett-Teller surface area analysis, and laser diffraction particle size analysis. The fuel used had the largest impact on the combustion behavior and hence the material properties. The high combustion temperature of glycine allowed for the formation of an FeAl 2 O 4 /Fe 3 O 4 solid solution, while the lower-temperature combustion of citric acid yielded Al-substituted γ-Fe 2 O 3 with high amorphous content. With citric acid, the specific surface area as high as 200 m2/g was achieved. The effect of Fe:Al precursor ratio was clearly seen in variations of the lattice parameter, which demonstrated the ability to tune the phase composition. The heating mode had minor effects on material properties, but some differences were observed. All products obtained by SCS in a microwave oven had low specific surface areas compared to those obtained with a hotplate and a muffle furnace. [ABSTRACT FROM AUTHOR]

In this paper, a new combustor with an output of 5 t/h is designed based on a computational particle fluid dynamics (CPFD) model. The flow field simulation is combined with the combustion simulation to analyze the internal two-phase flow, temperature field, and combustion products. The combustor structure was optimized. The simulation results show that the recovery efficiency of the waste sand and the energy utilization of the combustor can be improved under the original structure. The sand bed has a significant effect on flow field characteristics. The increase in particle temperature in the combustor increases the efficiency of waste sand recovery by increasing the height of the sand bed by 50 mm. The utilization rate of natural gas is increased and the economic efficiency is improved. The feasibility of the CPFD method can simulate the flow field characteristics inside the combustor very effectively. [ABSTRACT FROM AUTHOR]

Boron particles in solid-fuel ramjet combustion chambers typically exist in agglomerated form, and the gas composition within the chamber includes not only air but also propellant combustion products such as water vapor and CO2. This study investigates the thermal behavior, laser heating characteristics, and condensed-phase heating products of boron agglomerates in six distinct atmospheres: N2, O2, air, water vapor, CO2, and Ar. Thermal oxidation tests revealed that the reaction between boron and O2 dominates in an air atmosphere, while boron can still react with N2 in air to form granular boron nitride. Laser-induced heating resulted in ejection phenomena occurring in boron agglomerates when subjected to N2, air, water vapor, Ar, or O2 atmospheres, with the O2 atmosphere being the most conducive, exhibiting an average of 47 occurrences for individual agglomerates. The ejection process and frequency were found to be comparable in the air, Ar, and water vapor atmospheres, with an average ejection frequency ranging from 7 to 11 times. Although the ejection phenomenon occurred in the N2 atmosphere, its frequency was low, with an average of only two occurrences. Agglomerates underwent significant expansion before ejection, while single-particle boron did not exhibit ejection or expansion in any of these atmospheres. The highest surface temperatures of boron agglomerates upon laser heating in air, water vapor, N2, and Ar atmospheres were 2697.7 K, 2416.2 K, 2408.9 K, and 2392.1 K, respectively. Analysis of condensed-phase heating products revealed that boron agglomerates reacted with N2 or CO2 to form boron nitride or boron carbide, respectively. [ABSTRACT FROM AUTHOR]

As a novel green and high-performance propellants, H 2 O 2 /H 2 O/Al propellants have the potential to solve the pollution problem faced by composite solid propellants while maintaining high performance. However, the drawback that it cannot be ignited at a low oxidizer-to-fuel weight ratio (O/F) and a low pressure hinders its further development. Fortunately, this ignition defect was addressed by the mixture of hydrogen peroxide gel and micron-Al in our recent work. In this paper, the effects of Al content and particle size on the combustion characteristic of burning surface propagation and combustion products of the mixture were investigated. Combustion experiments were conducted in a windowed pressure vessel, using mixtures with three mixing ratios (fuel-lean, stoichiometric, and fuel-rich) and Al particle diameters between 1 and 12 μm. The burning surface propagation was captured by a high-speed camera. The particle size distribution, component, and morphology of combustion products were characterized by laser particle size analyzer, X-ray powder diffraction, and scanning electron microscopy, respectively. And it is the first time that the combustion properties of H 2 O 2 /H 2 O/Al propellants (including H 2 O/Al propellants) are studied from the prospective of particle size distribution of combustion products. Results showed that with the decrease of Al content and the increase of particle diameter, the combustion intensity of the mixture decreased, resulting in the agglomeration of melted Al droplets on the burning surface. When the Al content was decreased to O/F = 1.7, Al particles in the mixture were no longer further oxidized in the process of combustion. When the Al particle diameter was increased to 7–10 μm, burning rates of the mixture at O/F = 1.7–1.1 tended to be stable. The combustion of mixtures containing 3–7 μm was kinetically controlled. From the prospective of variable burning rate and efficient combustion, the appropriate Al content in the mixture was O/F = 1.7–1.1, and the Al particle diameter should be kept within 1–7 μm. • Two agglomeration mechanisms exist during the combustion of hydrogen peroxide gel and micron-Al mixtures. • Burning rates approach stable when Al particle diameter beyond 7–10 μm. • Al particles reach the oxidation limit during combustion when O/F = 1.7. • The morphology of combustion products is greatly affected by combustion intensity. [ABSTRACT FROM AUTHOR]

The Zhuque family, who lived in the Hexi Corridor on the ancient Silk Road, established LANDSPACE and has been exploring environmental, economic, and safety propellants. Little Zhuque visited LANDSPACE and learned about various liquid propellants, including liquid oxygen and kerosene with high thrust but easy carbon accumulation, environmentally friendly liquid oxygen and liquid hydrogen with high energy consumption, stable but toxic unsymmetrical dimethylhydrazine and nitrogen tetroxide. Finally, they discovered that the Zhuque Two carrier rocket, launched by LANDSPACE, was the world's first rocket to use liquid oxygen and methane as propellants. Liquid oxygen and methane are expected to have broader applications in the future due to their abundant reserves, easy storage conditions, safe transportation, complete combustion, and pollution-free combustion products. [ABSTRACT FROM AUTHOR]

Background: Chemical Intolerance (CI) is characterized by intolerances for chemicals, foods, and drugs with multi-system symptoms. As yet, the biomechanism remains unclear. One study reported converging lines of evidence supporting a substantive association between mast cell activation syndrome (MCAS) and CI. The purpose of this study is to (1) confirm a previous report demonstrating that 60% of MCAS patients report CI and (2) examine the parallels between symptoms and intolerances in CI and MCAS. Methods: Five hundred forty-four MCAS patients were assigned a clinical MCAS score using a validated assessment instrument and were assessed for CI using the validated Quick Environmental Exposure Sensitivity Index. Results: Our outcomes confirm the previously published study where the majority of MCAS patients also have CI. There was a clear overlap between various ICD-10 diagnostic categories and CI symptoms, providing further support for a potential shared mechanism. Conclusions: Exposures to pesticides, volatile organic compounds, combustion products, and mold have previously been reported as initiators of CI. However, until recently, little was known about the biological mechanism involved that could explain the multisystem symptoms associated with CI. This paper addresses a newly identified biomechanism for disease, which may underlie a host of "medically unexplained symptoms" triggered by xenobiotics. [ABSTRACT FROM AUTHOR]

The shortage of fossil fuels and their rising prices, as well as the global demand for renewable energy and the reduction in greenhouse gas (GHG) emissions, result in an increased interest in the production of alternative biofuels, such as biodiesel or biomass pellets. In this study, the possibility of utilizing waste glycerol, as an addition to pine pellets intended for heating purposes, has been investigated. The usefulness of pellets containing glycerol additions has been compared in terms of applicable quality standards for wood pellets. The highest values of moisture (4.58%), ash (0.5%) and bulk density (650 kg/m3) were observed for pellets without glycerin waste. The addition of waste glycerol slightly increases the calorific value of the pellet (17.94 MJ/kg for 7.5% additive). A 10-kW domestic biomass boiler has been employed to burn the tested pellets. The consumption of analyzed fuels during boiler operation was determined. The concentration of CO, CO2 and NOx in exhaust gases has also been examined. It was observed that the addition of 7.5% of waste glycerol contributes to the reduction in NOx concentrations by 30 ppm and CO2 by 0.15%. The obtained experimental results were compared with the numerical calculations made with the use of ANSYS Chemkin-Pro. The conducted research indicates the legitimacy of utilizing waste glycerol as an additive to wood pellets. In addition, this type of addition has a positive effect on, among others, the increase in calorific value, as well as lower emissions of combustion products such as NOx and CO2. [ABSTRACT FROM AUTHOR]

Background: Most smokers know that smoking is harmful to health, but less is known about their understanding of what causes the harms. The primary aim was to examine smokers' perceptions of the relative contributions to smoking-related morbidity from combustion products, nicotine, other substances present in unburned tobacco, and additives. A secondary aim was to evaluate the association of these perceptions with nicotine vaping product use intentions, and quitting motivation/intentions. Methods: Participants were current smokers and recent ex-smokers from Australia, Canada, England and the United States (N = 12,904, including 8511 daily smokers), surveyed in the 2018 International Tobacco Control Four Country Smoking and Vaping Survey. Respondents reported on how much they thought combustion products, nicotine, chemicals in the tobacco and additives in cigarettes contribute to smoking-related morbidity (none/very little; some but less than half; around half; more than half; all or nearly all of it; don't know). Results: Overall, 4% of participants provided estimates for all four component causes that fell within the ranges classified correct, with younger respondents and those from England most likely to be correct. Respondents who rated combustion as clearly more important than nicotine in causing harm (25%) were the least likely to be smoking daily and more likely to have quit and/or to be vaping. Among daily smokers, all four cause estimates were independently related to overall health worry and extent of wanting to quit, but the relative rating of combustion compared to nicotine did not add to prediction. Those who answered 'don't know' to the sources of harm questions and those suggesting very little harm were consistently least interested in quitting. Conclusions: Most smokers' knowledge of specific causes of harm is currently inadequate and could impact their informed decision-making ability. [ABSTRACT FROM AUTHOR]

Traditional incinerators achieve the thermal requirements through heat transfer and heat radiation. However, the early recovery of flue gas preheats the air and yields nitrogen oxide (NOx) to rise in the combustion of overoxygen. The operation of an incinerator inevitably implies the release of greenhouse gases and emissions of NOx harmful to the human health. The administrator of one laboratory incinerator in Taiwan sought to optimize the operation conditions such as temperature or oxygen level of the combustion products within the combustion chamber to minimize the release of pollutants and maximize the efficiency of combustion. In this phase, air-fuel ratio control and air volume control are regarded as the first priority. A numerical model of the laboratory-scale plant in southern Taiwan is established by using enhanced wall treatment and coupling the thermochemical conversion of volatile waste to the gaseous combustion of the released syngas. The model allows users to characterize the temperature and retention time of the combustion products for the verification of the fulfillment of the existing regulation for NOx and oxygen level in incineration plants. It shows trade-off relationship between combustion efficiency of fuel and emissions (NOx and CO) in surveying cases of air-fuel ratio (AFR) ranges from 1.5∶1 to 14.4∶1 according to numerical results. Increasing the air volume enhances this trend. In this study, it shows the lowest emissions of NOx in case of AFR=1.5∶1 , but worse combustion efficiency. Meanwhile, to increase the air volume by 1.15 times suppress most CO and about 28% NOx, but increases by 6% the residual fuel. The averaged distribution of retention time of particles in this study ranged from 30 to 50 s, and is provided for further improvement of geometry in the next phase. [ABSTRACT FROM AUTHOR]

A method is developed to produce large titanium monolithic burning particles with a diameter of 250–550 μm. The combustion of titanium particles in free fall in air is investigated. The characteristic times of the beginning of fragmentation, end of fragmentation, and end of burning as well as the laws of motion of particles (in particular, coordinate and velocity at the starting moment of fragmentation) are determined using video recording. The size of particles at which the fragmentation mode changes from "star" to "fir branch" is estimated. [ABSTRACT FROM AUTHOR]