Fuel Additives Research Articles

Genesis and accumulation mechanism of external gas in deep coal seams of the Baijiahai Uplift, Junggar Basin, China

Coal seams are typically self-sourced reservoirs. However, in certain special cases, the coal seams also contain large amounts of external gas from other source rocks. Successful development strategies in relation to Jurassic coalbed methane (CBM) in recent years have confirmed the presence of large amounts of external gas within the coal seams of the Baijiahai Uplift, Junggar Basin, China, which has important exploration and development prospects. However, the genesis and source of Jurassic CBM in the area remain unclear, limiting our understanding of its formation and accumulation as well as the planning of further development strategies. Based on a comprehensive analysis of the geochemical characteristics of Jurassic CBM, combined with research on the burial and thermal evolution history of the Jurassic coal seams, this study discusses the production curves of typical wells as well as regional tectonic styles, genesis, source, and accumulation of Jurassic CBM in the Baijiahai Uplift. Depending on the genesis, Jurassic CBM in the study area is divided mainly into coal-type (humic-type) gas, oil-type (sapropelic-type) gas, and mixtures of them, all of which are thermogenic gases of medium to high maturity. There are two main sources of Jurassic CBM in the Baijiahai Uplift. On the one hand, it comes from the vertical migration of gas generated by Permian and Carboniferous source rocks in the Baijiahai Uplift directly. On the other hand, it comes from the regional lateral migration from the Dongdaohaizi and Fukang Sags. Gas generated by source rocks in the Dongdaohaizi and Fukang Sags is driven by pressure, migrates towards the Baijiahai Uplift through sandstone channels, and accumulates in the Jurassic coal seams through faults. Compared with common self-sourced coal seams, enrichment of the coal seams with large amounts of external gases requires two necessary conditions: (1) Other layers of gas-generating source rocks are present at levels deeper than those of the coal seams, constituting additional gas sources for the coal seams, and (2) an open fault system is developed regionally, providing pathways for gas from other layers to enter the coal seams.

Investigation on the thermodynamic performance and machinery mass in the N2O-based mixtures recompression Brayton cycle for a nuclear-powered spacecraft

As a reliable energy system with a long service life, nuclear energy can produce massive power for spacecraft in deep space exploration. Due to the compact layout and excellent performance, the supercritical recompression Brayton cycle has received extensive attention and has become a hot research topic in thermoelectric conversion technology. The critical properties of the working medium are a constraint on the cycle performance. Adding additional gas into a pure S-N2O working medium can effectively change the properties of the critical point and improve the cycle performance. However, there is no standard for selecting appropriate binary mixture components to determine which additive gas can improve cycle efficiency. In this work, several gases are chosen as the potential N2O-based mixtures (N2O-O2, N2O-He, N2O-Kr, N2O-Ar, N2O-H2S, N2O-CO, N2O-SO2, N2O-CH4, N2O-C2H6, N2O-C3H8, N2O-C4H8, N2O-C4H10, N2O-C5H10, N2O-C5H12, N2O-C6H6) as the working medium in the system. The detailed sensitivity analysis reveals the influence of essential parameters (the split ratio, pressure ratio, selection minimum operating temperature, maximum operating temperature, and minimum operating pressure) on the thermodynamic efficiency and Brayton machinery unit mass. According to the analysis results, the thermal efficiency improves with an increase in the split ratio, pressure ratio, and maximum operating temperature and decreases in the selection minimum operating temperature and minimum operating pressure for all mixtures. The exergy efficiency also showed a similar variation trend. However, the influence of the maximum working temperature on it is different from that of the thermal efficiency, which decreases with the increase of the maximum working temperature. The cycles operated close to the critical area can provide better cycle performance, and N2O-He has the best thermal performance among all proposed N2O-based mixtures, which can be used as a potential choice as the working medium for future nuclear-powered spacecraft.

Mechanism of formation of p-benzylenephenol peroxide radical (p-PhC(O2•)HPhOH).

The reactions of radicals with O2 play the important role in the biological, medicinal, and industrial processes. The mechanism of this reaction is studied previously for the alkane, alkene, alkyne, phenols, and close-related radicals. According to these studies, the formation of intermediates in these reactions is predicted only for the aromatic radicals. Thus, the Van der Waals complexes of O2 with phenyl or benzyl radicals are predicted, as well as the π-π cluster for benzene. However, the possibility of the formation of such intermediate π-π clusters in the case of bisphenol radicals and the thermochemistry of its formation is not studied. Bisphenols are one of the main components of bio-oil, produced during pyrolysis of lignin-contained biomass. Synthetic bisphenols are used in polycarbonate plastics, epoxy resins, and thermal papers. Their mechanism of oxidation is important for the determination of fire safety of these materials, the possibility of using them as additives for fuels for the decreasing and the description of the ignition delays, as well as for the determination of its health risk assessment in medicine. The five DFT (M06-2X (i = 1), B3LYP (i = 2), wB97XD (i = 3), M08HX (i = 4), MN15 (i = 5)) approaches with 6-311 + + G(d,p) basis set are used for the determination of standard enthalpies of atomization (ΔraHo(Yi)) of considered compounds (molecules, radicals, and transition states). These values of ΔraHo(Yi) are corrected using the empirical linear calibration dependencies, reported previously. The different calibration dependencies are used for the hydrocarbons (including the aromatics and simple oxygenated derivatives) and for the peroxides. The corrected values of ΔraHo(Yi, CORR) are used according to Hess's law for the determination of ΔfHo(Yi, CORR). The most consistent values of ΔfHo(Y, MEAN) are derived from the coordination of the values of ΔfHo(Yi, CORR) using the intersection of their values of standard deviations (3SDi). These values of ΔfHo(Y, MEAN), as well as the B3LYP values of So(Y), which are accounting the frequency correction and internal rotations, as well as their temperature dependencies, are used for the determination of thermochemistry of considered reactions and of the calculation, within transition state theory (TST), of the values of high-pressure limits of the rate constant. The values of Ho(Yi), So(Yi), and Go(Yi) are calculated using the Gaussian 16w program. The temperature dependencies of thermochemical properties and the values of rate constants are determined using the ChemRate program (v.1.5). The optimized structures are visualized using the Chemcraft.

Emerging organic contaminants in the soil-plant-receptor continuum: transport, fate, health risks, and removal mechanisms.

There is a lack of comprehensive reviews tracking emerging organic contaminants (EOCs) within the soil-plant continuum using the source-pathway-receptor-impact-mitigation (SPRIM) framework. Therefore, this review examines existing literature to gain insights into the occurrence, behaviour, fate, health hazards, and strategies for mitigating EOCs within the soil-plant system. EOCs identified in the soil-plant system encompass endocrine-disrupting chemicals, surfactants, pharmaceuticals, personal care products, plasticizers, gasoline additives, flame retardants, and per- and poly-fluoroalkyl substances (PFAS). Sources of EOCs in the soil-plant system include the land application of biosolids, wastewater, and solid wastes rich in EOCs. However, less-studied sources encompass plastics and atmospheric deposition. EOCs are transported from their sources to the soil-plant system and other receptors through human activities, wind-driven processes, and hydrological pathways. The behaviour, persistence, and fate of EOCs within the soil-plant system are discussed, including sorption, degradation, phase partitioning, (bio)transformation, biouptake, translocation, and bioaccumulation in plants. Factors governing the behaviour, persistence, and fate of EOCs in the soil-plant system include pH, redox potential, texture, temperature, and soil organic matter content. The review also discusses the environmental receptors of EOCs, including their exchange with other environmental compartments (aquatic and atmospheric), and interactions with soil organisms. The ecological health risks, human exposure via inhalation of particulate matter and consumption of contaminated food, and hazards associated with various EOCs in the soil-plant system are discussed. Various mitigation measures including removal technologies of EOCs in the soil are discussed. Finally, future research directions are presented.

Mechanism Analysis and Multiobjective Optimization of Efficient and Energy-Saving Separation of Green Fuel Additives via Extractive Pressure Swing Distillation with an Ionic Liquid Mixed Entrainer

Mechanism Analysis and Multiobjective Optimization of Efficient and Energy-Saving Separation of Green Fuel Additives via Extractive Pressure Swing Distillation with an Ionic Liquid Mixed Entrainer

Innovative optimal risk and economic management of a hybrid electric/hydrogen refueling station with water electrolyze and steam methane reform technologies for hydrogen supply

This paper proposes a stochastic programming for the economic operation of an electric/hydrogen refueling station. To reduce the carbon footprint, the charging station is connected to solar power generation, electrolyzer, and fuel-cell device to interlink the electric and hydrogen energies. Extra hydrogen is procured through an innovative steam methane reform process, which charges additional gas prices and emission penalties in return. The optimal scheduling minimizes the operation cost of the charging station and the emissions produced. The decision-maker faces uncertainties of electricity price, solar power generation, and vehicle demand that are modeled using stochastic programming. The innovative method based on conditional value-at-risk method is proposed to develop risk-hedging strategies addressing financial risks using economic management. With this respect, the risk-aversion strategies increased the expected cost from $ 322.97 to $ 388.71 (about 17 %) and decreased the difference between the expected cost and the cost of the worst scenario from $ 78.04 to $ 12.30 (about 84.23 %). Moreover, expected risk reduced from $ 24.63 to $ 1.23.

Introduced gas regulating fast and highly exothermic reactions with in situ gas generation in microreactors

AbstractThe oxidation of cyclohexanol/cyclohexanone with nitric acid as a fast and highly exothermic process was hard to control at low molar ratios of oxidant to organic substrate even in microreactors. Process of runaway gas generation was observed due to the local hot spots, which decreased the selectivity of adipic acid. Additional gas was introduced into microreactors before the reaction, changing the previous wave annular flow to the uniform slug flow. Through the microscopic high‐speed photography and CFD simulation, it was found that the internal convection made the reactant molecules in the aqueous slug distribute evenly instead of gathering near the interface before, thus eliminating the local hot spots and stabilizing the hydrodynamic characteristics. The reaction performance was evaluated under different conditions, and a higher adipic acid selectivity of 93.6% was achieved at a molar ratio of 6.7 with the combination of microreactors and conventional reactors.

Novel variants conceptional technology to produce eco-friendly sustainable high octane-gasoline biofuel based on renewable gasoline component

The creation of green engine fuels from renewable and sustainable gasoline additives is essential as a consequence of ecological concerns and the energy problem. Bio-alcohols are currently a promising sustainable fuel substitute for gasoline in automotive transportation. In this perspective, the ongoing investigation intends to evaluate the influence of sustainable and renewable petrol additives, like isopropanol, which has outstanding anti-detonation properties and great chemical and physical characteristics on reformable naphtha (HSRN) and light naphtha (LSRN), which possess low chemical and physical characteristics, and low octane rating. Additionally, the second goal is to create biofuel with an eco-octane number of high by blending other gasoline components than those previously indicated. Several gasoline fuels and experimental setups compliant with European standard norms were used to carry out the current work. The results reported that gasoline RON92, RON95, and RON98 were produced based on isopropanol as a renewable and sustainable resource. Moreover, the quantity and quality of light naphtha were maximized. Likewise, the laboratory findings reported that the antiknocking efficiency could be ranked sequentially as isopropanol > reformate > isomerate > fluidized catalytic cracked gasoline (FCC) > PRF-70 > LSRN > HSRN by octane rating. Furthermore, the Reid vapor pressure (RVP) for petrol RON92 was bigger than gasoline RON95 and RON98, unlike the density at 15 °C for gasoline RON 98 was bigger than gasoline RON92 and RON95. Finally, major problems like energy, water scarcity, and the environment affect people all around the world. Two of the earlier environmental and energy-related problems will be resolved by using these sustainable and renewable additions.

Macroscopic and stable gas film obtained by superhydrophobic step and its drag reduction performance

Drag reduction technology has a promising application in marine fields and has drawn much interest in scientific fields. Superhydrophobic surface has been proven to be effective in drag reduction due to thin film of gas adsorbed on surface because of its low friction drag and large slip length. Here, macroscopic and stable gas film was observed when water flowed over superhydrophobic surface with step without additional gas injection under laminar flow and turbulent flow. Superhydrophobic surface was prepared with contact angle more than 150° and roll-off angle nearly 0°. Macroscopic gas film could maintain under laminar flow and turbulent flow and keep up to 80% after 1 h water flowing with optimized parameters of step, showing different morphological deformations under different velocities and Reynolds numbers. Compared with untreated hydrophilic surface, superhydrophobic surface with step exhibited good drag reduction performance with maximum drag reduction rate 20% under laminar flow and turbulent flow, after optimizing of height of step and distance between steps. Mechanisms of gas film drag reduction were the ultra-low skin friction drag force between liquid–gas interface, large slip length on liquid–gas interface, and flexible gas film surface acted like compliant wall. Gas film of millimeter scale was much larger than thickness of boundary layer and reduced turbulence intensity near wall. This work provides a new way to obtain macroscopic gas film and analyze liquid–gas interface.

Near-infrared thin-film electroluminescent device from ZnGa2O4:Cr3+ on silicon wafer

This study systematically investigated the Cr3+-doped ZnGa2O4 electroluminescent (EL) device, demonstrating the emission of near-infrared (NIR) light. The ZnGa2O4:Cr3+ film was prepared by a facile and cost-effective method within all-air atmosphere processes. It consists of a naturally grown amorphous SiOx and an optically active ZnGa2O4:Cr3+ layer. Under a sinusoidal voltage waveform, the device emits an NIR spectrum without the need for additional background gas or other implantation methods. The proposed mechanism suggests that light generation occurs through hot electrons released from the amorphous SiOx layer, injected into the active layer, leading to impact-ionization. The optical characteristics of the EL device are presented, and its response to applied polarities is thoroughly investigated. Finally, given the cost-effectiveness of our EL device preparation, this proposed research is of considerable importance for advancing the development of EL devices in silicon photonics.

The effects of limonene and eugenol additives in n-heptane and low-octane gasoline on the emission characteristics and fuel consumption of single-cylinder gasoline engine

This study investigated the effects of two additive polarities: polar (eugenol) and nonpolar (limonene) additives blended into n-heptane and low-octane gasoline. These compounds were chosen due to their unique molecular structure characteristics which influences the exhaust emissions. The physicochemical properties, fuel consumption, and exhaust gas emissions of a single-cylinder gasoline engine were measured. Four fuel blends were created by blending eugenol and limonene on a volumetric basis, n-heptane-eugenol (NHE), n-heptane-limonene (NHL), low-octane gasoline-eugenol (GE), and low-octane gasoline-limonene (GL). Tests were conducted on a single-cylinder gasoline engine. The exhaust gas emissions were analyzed using gas chromatography, and the role of each additive substance in the formation of carbon monoxide (CO), unburned hydrocarbon (HC), residual oxygen (O2), and carbon dioxide (CO2) emissions was validated using Hyperchem simulation and gas chromatography mass spectrometry. Owing to differences in the molecular structure and energy content of the two additives, the fuel consumption of NHE-fueled vehicles increased by 19.69% compared to NHL, whereas GE decreased by 32.15% compared to GL. Owing to the presence of oxygen atoms and low binding energy, blending eugenol with n-heptane and low-octane gasoline significantly reduced CO by 1.87% higher than limonene. However, eugenol’s aromatic structure can only reduce 14.45% of HC emission, while limonene, with its dynamically moving electrons and nonpolar properties can reduce up to 18.24%. It was discovered that the two additives could improve the quality of exhaust gas emissions.

A strategy for industrial waste mitigation—thermal treatment of non-woven polyester fabric debris on ultrahigh-porosity MgO under CO2 atmosphere

Unproperly treated industrial waste creates serious environmental pollution that requires immediate remediation strategies. Non-woven polyester fabrics are widely used in a variety of industrial applications; thus, their debris becomes a major portion of industrial waste. To contribute to advanced industrial waste treatment processes, this study investigated catalytic thermal treatment of non-woven polyester fabric debris on a novel ultrahigh-porosity MgO material under a CO2 environment. The ultrahigh-porosity MgO was synthesized from hydromagnesite via a series of thermal reactions, having a surface area of 208.8 m2 g−1, total pore volume of 0.34 cm3 g−1, and average pore diameter of 2.37 nm. Using the MgO as the catalyst for thermolysis of non-woven polyester fabric debris in CO2 promoted thermal cracking of volatilized species evolved from the non-woven polyester fabric debris thermolysis, thereby increasing the gas product yield and decreasing the liquid product and wax yields. In addition, dehydrogenation and reverse water gas reaction was promoted by the MgO catalyst, leading to more than higher syngas production (up to 16.1 wt% syngas yield) compared to non-catalytic thermolysis (up to 8 wt% syngas yield). The selectivity toward esters was increased, while the selectivities toward benzoic and phthalic acids were decreased, most likely due to the MgO promoting decarboxylation and esterification reactions during the thermolysis. Moreover, the ultrahigh-porosity MgO catalyst was reusable for at least two consecutive cycles. It is hoped that the applicability of the novel material as a catalyst is widened for advanced treatment processes to minimize negative effects of industrial wastes on the environment.

BT100, a three-in-one, multipurpose disinfecting, deodorizing, and air-cleaning solution with an effective, gradual, and continuous gaseous chlorine dioxide-releasing substance

Aerosols carrying viruses that are released from the oral cavity of infected individuals are the primary, if not the only, means of transmission during viral respiratory disease epidemics. This makes crowded rooms and tiny, enclosed public areas like bathrooms prime environments for the transmission of diseases. Volatile organic compounds (VOCs) and formaldehyde are two contaminants that pose serious threats to human health and well-being in indoor environments. The varied disinfectant properties of chlorine dioxide (ClO2) make it a key player in treating a range of air quality issues. To balance effectiveness and safety, however, the careful application of chlorine dioxide is essential to achieving the best results in air quality while preserving human health and well-being. This study explores the many functions of chlorine dioxide, including the prevention of the spread of viruses, the elimination of harmful gases like ammonia and hydrogen sulfide, and its effects on formaldehyde and total volatile organic compounds (TVOCs) in indoor environments using BT100. The results indicate a reduction of 98.5%, 81.01%, 62.22%, 46.5%, and 63.84% in minimizing aerosolized viruses, ammonia, and hydrogen sulfide gas in addition to formaldehyde and total volatile organic compounds.

Ethyl levulinate ketalization with glycerol promoted by H,Y-Zeolite: Kinetic analysis in batch and continuous milli-reactor scale

Ketals from levulinic acid are considered emerging compounds which have obtained growing interest in last years. Their possible applications are different, from additives for fuels to plasticizers, polymers and solvents. Ketals can be obtained starting from levulinic acid and its esters. The advantages in using the esters, such as ethyl levulinate, can be found in avoiding the occurrence of the competitive esterification reaction. In this work, the attention was focused on the reaction between ethyl levulinate and glycerol to obtain the five-membered ketal. The reaction was made in the presence of H,Y-zeolite as catalyst investigating the kinetics in batch reactor and in a continuous milli-reactor simulating all the experimental data with a mathematical model. The activation energy was measured both without catalyst (Ea = 104 kJ/mol) and for the catalyzed experiments (Ea = 48 kJ/mol). The reaction showed an endothermic behavior as demonstrated by the reaction enthalpy (ΔrH = 41 kJ/mol). The feasibility of the operation in flow was demonstrated using a milli-reactor. From data interpretation, the fluid–solid mass transfer coefficient was calculated for each volumetric flow. The present study tracks the basis for a future scale-up of the process.

Potential toxic heavy metals in village rainwater runoff of antimony mining area, China: Distribution, pollution sources, and risk assessment

The potential toxic heavy metal runoff from antimony mining areas poses a serious threat to the water environment and the health of residents in the village. The study found that the average concentrations of As, Sb, Cr, Pb, and Cd in the runoff were 0.1237, 0.1148, 0.0332, 0.0140, and 0.0013 mg/L, which were higher than the normal average concentrations in the water environment of 0.018, 0.0009, 0.05, 0.012, and 0.000013 mg/L, respectively.Sb and As are severely polluted, while Cd, Pb, and Cr have lower pollution levels. The coefficients of variation for As, Sb, Cr, Pb, and Cd range from 0.079 to 1.051, with Sb showing exceptionally high variability. Heavy metal elements Pb, Cd, and Sb accumulate in the southeastern area of the village, with Sb concentrations decreasing from the southeast to the northwest. As is mainly distributed in the northeastern part of the village, while Cr is primarily found in the central-western region. Source analysis indicates that As and Sb originate from mining and industrial activities, dust deposition, and domestic sewage. Cr comes from the natural geological background and metal product industry, Pb from lead-acid batteries, industrial activities, and gasoline additives, and Cd from fertilization in residential green areas and pesticide use. Health risk analysis reveals that the hazard index (HI) values for As and As in the water environment are 1.49 and 2.31, respectively, both exceeding 1, posing a serious threat to the health of village residents. The HI values for Pb, Cr, and Cd elements are all below 1, indicating lower risks. This study identified that Sb in the antimony ore area and its associated metal element As are the main elements leading to potential heavy metal pollution in the runoff of village residential areas, providing direction for subsequent water environment restoration work.

Impact of Lithium‐Ion Battery Separators on Gas Evolution during Temperature Abuse

AbstractSeparators in lithium‐ion batteries are typically considered to be electrochemically inert under normal operating conditions. Yet, temperature abuse tests at elevated temperatures of ca. 60 °C to 132 °C show that the choice of separator material has a decisive influence on battery behavior and degradation. Using online electrochemical mass spectrometry, we analyzed the evolution of cell voltage and gas products during and after thermal abuse for different separators. Polypropylene and polytetrafluoroethylene seem exhibited little change in gas evolution, producing only modest amounts of CO2 and POF3. In contrast, glass fiber and polyethylene terephthalate separators caused additional gas release, indicating electrochemical instability. Polyethylene terephthalate produced significantly more gas, resulting in the mechanical failure of the separator and drastic performance losses. The amount of CO2 evolved with polyethylene terephthalate is four times higher than that of the glass fiber separator. However, the amount of POF3 detected was five times higher for the glass fiber separator.

Effect of Di-tert Butyl Peroxide on Diesel Engine Performance Fuelled by Biodiesel Blends

This study is motivated by the fact that the vegetable oils are being considered as the fuel of the future for the internal combustion engines, especially the compression ignition engines which are working with diesel as fuel. Different approaches for using the vegetable oils in CI engines as fuel are either to modify the oils to match with that of diesel to run successfully with these oils. Fuel additives are compounds formulated to enhance the quality and efficiency of the fuels used in motor vehicles. There are several benefits associated with the use of fuel additives. Di-tert butyl peroxide (DTBP) is effective for enhance the quality and efficiency of the fuels used in CI engine. The investigation was to check the feasibility of di-tert butyl peroxide as an additive in different blends of diesel and jetropha bio-diesel on engine performance. The short-term tests on an unmodified diesel engine were conducted using the bio diesel and di-tert butyl peroxide blends (0, 10, 20, 30, 40, 50, and 100 per cent and 0, 0.5, 1.0, 1.5, 2.0, 2.5 per cent) with diesel. The engine performance and emission characteristics were measured during the short-term test. In all types of fuel, with increased percentage of load, brake specific energy consumption (BSEC) of the engine was observed to be decreased, on the other hand brake thermal efficiency, fuel consumption rate, sound level (db.), exhaust temperature, and the engine exhaust emissions like CO2, CO, HC and NOx was increased, respectively.

PERFORMANCE CHARACTERIZATION, PRICE EVALUATION, AND ESTIMATION OF EMISSIONS OF INTERNAL COMBUSTION ENGINES WITH FUEL ADDITIVES

Fuel prices have been escalating day by day due to resources being limited. The key focus of this research is to evaluate the performance of internal combustion engines by the inverse correlation between fuel prices and engine efficiency and to encourage future advancements in the development of efficient fuels for automobiles. Investigations indicate the impact of various fuel additives, such as butane, ethane, propane, cracking liquid (0X11257), and XAG 818, on the fuel's characteristics. This work attempts to analyze existing data on fuel prices using mathematical tools like MATLAB and the various factors affecting them over the years. The analysis shows that there is about a 14% increase in values of engine parameters, such as brake thermal efficiency. The heat energy generated with suitable fuel additives was 12.69% more than low-quality fuel additives. Therefore, using excellent high-quality fuel additives benefits engine health and performance.

Preparation and characterization of graphene film using biogas derived from oil palm empty fruit bunch (OPEFB) by chemical vapor deposition (CVD) method

This study aims to fabricate graphene films using biogas derived from oil palm empty fruit bunch (OPEFB) as carbon precursors using chemical vapor deposition (CVD) method under various conditions. The fabricated graphene films were deposited on copper substrates at different temperatures and gas compositions. Scanning Electron Microscopy (SEM), Raman Spectroscopy, and the I-V test were used to analyze and characterize the properties of the fabricated film. From the characterization results, SEM images of films grown at 800°C (without additional H2 gas), and 900°C (without additional H2 gas) show a not so well-defined hexagonal domain shape with non-uniform morphology with variations in domain shape and orientation, while Raman spectra show it has only the D band and G band which are attributed to graphene oxide. On the other hand, at 900°C (with additional H2 gas), the SEM image shows more defined hexagonal domain shape and variations in domain shape and orientation, as well as the D, G and 2D band on the Raman spectra, which are like graphene with defects structure. Hence, it is concluded that graphene film was successfully produced at 900°C with additional H2 gas.

Post-earthquake fires: risk assessment and precautions

Earthquakes have great damage potential and importance in risk management and structural engineering, causing fires in buildings such as residences and commercial spaces. Post-earthquake fires (PEF) are secondary disasters that can cause material and moral destruction and loss of life. Similar to natural disasters, they show the time of occurrence and possible scenarios in places. This study aims to analyse and examine what precautions can be taken to prevent or minimize PEF through risk assessment. In this study, a literature review was conducted with the tracking method, focusing on examples from the world where the fires that occur as a secondary effect of the earthquake can cause devastating damages and significant disasters, and inferences are made by classifying the data obtained. Many factors, such as gas leaks due to earthquakes, cracks in pipelines, and short circuits in electrical installations, can cause fires. In addition, flammable liquid or combustible gas emissions and fire protection disturbances create significant fire hazards after earthquakes. In this paper, in which the causes and consequences of fires are analysed, risks, the evaluation process depending on the risks, the precautions that can be taken according to the situations that the risks will cause, and the models developed are emphasized. The research is a reference study with the expectation that there will be an increase in the number of studies examining experimental and physical PEF models.