Fire Research Articles

Fire Fighter Robot Using IOT and Mobile Application

In today's fast-paced world, fire hazards pose significant risks to life, property, and the environment. Traditional fire detection systems often rely on human intervention, leading to delays in response time and exacerbating the damage caused by fire incidents. Our project, the IoT-Based Automatic Fire Detection and Extinguisher Robot, addresses this challenge by utilizing a combination of modern sensor technology, robotics, and IoT to provide an autonomous and real-time solution. The robot is equipped with flame and temperature sensors that allow it to detect fires at an early stage. Once a fire is detected, the robot activates its movement mechanism using DC motors to navigate toward the fire while the integrated servo-controlled water pump precisely sprays water to extinguish the fire. In addition to automatic firefighting, the robot features obstacle detection using ultrasonic sensors, ensuring safe navigation in complex environments. The system includes Bluetooth and Wi-Fi communication, allowing for remote control via an Android mobile app. This app provides both manual and automatic control options and sends real-time fire alerts when the robot detects a fire. This autonomous system minimizes human intervention, speeds up response times, and reduces fire damage effectively. The robot is powered by an ESP32 microcontroller, which processes data from the sensors and controls the motors and water pump. The rescue pod feature allows the robot to perform additional operations like transporting sensitive materials during emergencies. The system's IoT functionality enables real-time alerts and remote monitoring, enhancing its capability as a scalable and cost-effective solution for residential, commercial, and industrial fire safety.

Novel keratin-based particles encapsulating essential oils: A step towards developing sustainable biopesticides

Essential oils (EOs) are playing a pivotal role in pest control within biologic farming due to their botanical origin and potential as biocontrol agents. However, their use is still limited by challenges like high volatility, rapid oxidation, and susceptibility to degradation in field conditions. Additionally, EOs might present some health risks to humans through inhalation or direct contact during application. Encapsulation of EOs holds promise by enhancing essential stability and activity, while reducing their volatility and potential cytotoxicity. EOs from Satureja montana (Winter Savory), Mentha piperita (Peppermint) and Thymus vulgaris (Thyme) were investigated, both in their free form or encapsulated into keratin-based particles, representing a novel class of biopesticides. Particles containing 15 mg/mL of keratin encapsulating the EOs were stable over time with sizes below 650 nm and demonstrated particle formation and encapsulation efficiencies higher than 90 %. The keratin-based particles exhibited a release of approximately 12 %, 43 %, and 51 % for M. piperita EO, S. montana EO, and T. vulgaris EO, respectively, during a 48-hour in vitro evaluation. When tested for cytotoxicity in human fibroblast cells, the free EOs exhibited greater cytotoxic effects compared to their encapsulated forms, especially at higher concentrations. Encapsulation of EOs into keratin-based particles significantly reduced their harmful impact on cells, demonstrating the protective effect of these formulations. This reduction in cytotoxicity suggests potential for further exploration of these encapsulated EOs as alternatives to conventional pesticides. However, their efficacy against pests and their toxicity towards non-target species requires further validation.

Epicardial Adipocytes in Cardiac Pathology and Healing.

Implications of epicardial adipose tissue (EAT) on the development of coronary artery disease (CAD) have garnered recent attention. Located between the myocardium and visceral pericardium, EAT possesses unique morphological and physiological contiguity to the heart. The transcriptome and secretome of EAT differ from that of other fat stores in the body. Physiologically, EAT protects the adjacent myocardium through its brown-fat-like thermogenic function and rapid fatty acid oxidation. However, EAT releases pro-inflammatory mediators acting on the myocardium and coronary vessels, thus contributing to the development and progression of cardiovascular diseases (CVD). Furthermore, EAT-derived mesenchymal stromal cells indicate promising regenerative capabilities that offer novel opportunities in cell-based cardiac regeneration. This review aims to provide a comprehensive understanding and unraveling of EAT mechanisms implicated in regulating cardiac function and regeneration under pathological conditions. A holistic understanding of the multifaceted nature of EAT is essential to the future development of pharmacological and therapeutic interventions for the management of CVD.

Investigation on Fire Damage Caused by Breakage of Shielding Layer in Extruded Three-layer 6.6kV XLPE Cables

Investigation on Fire Damage Caused by Breakage of Shielding Layer in Extruded Three-layer 6.6kV XLPE Cables

Study on the anti-ablation behavior of (Ti,W)3AlC2 under oxyacetylene flame above 2500 K

To evaluate the reliability of (Ti,W)3AlC2 in aerospace ablation conditions, the ablation behavior of (Ti,W)3AlC2 ceramic is investigated by using oxyacetylene flame above 2550 K. Results show a four-stage process exists with the formation of TiO2-Al2TiO5-Al2O3. Once the central ablation temperature exceeds 2350 K, the innermost Al2O3 layer melts and collapses, exposing the decomposed TiCx-Al matrix directly to the flame with rapid oxidation and a remarkable increase of the linear ablation rate. The melt finally flows out with the flame from the ablation center and solidifies into a stripe-like TiO2-Al2TiO5 eutectic oxide above the protective oxide layer. The refractory W particles detected in the eutectic TiO2-Al2TiO5 may retard the flowing rate of the fluid by increasing its viscosity, resulting in a better ablation resistance performance in the later period of the ablation process, making the linear ablation rate lower from 10.30 μm/s of Ti3AlC2 to 9.01 μm/s of (Ti,W)3AlC2.

A simplified procedure for evaluation of damage-depth in concrete exposed to high temperature using the impact-echo method

Concrete is widely recognized as a material capable of withstanding the intrusion of high temperatures during fires. However, under different high-temperature conditions, concrete can still experience strength reduction, cracking, or spalling, which can significantly impact the safety and durability of concrete structures. Conventionally, the wave refraction technique was used to detect the depth of this damage layer. However, the wave refraction technique is a time-consuming point-by-point detection method. In order to increase detection efficiency, this paper proposes a simplified method based on a single-point test. Numerical analysis of the thermal conduction of a concrete slab exposed to elevated temperature was performed first to investigate the temperature distribution within the concrete slab. Subsequently, the wave refraction technique was numerically simulated to evaluate the damage depth of the concrete slab. According to the refracted wave propagation path, a simplified procedure is proposed for the detection of the damage depth of concrete under high temperature. In the simplified procedure, a receiver is placed at an adequate distance from the impact source so that the first arrival wave at the receiver will be a wave refracted from the interface between the damaged layer and the sound layer inside the concrete. To verify the applicability of the proposed simplified procedure, concrete slab specimens subjected to an elevated temperature of 600 °C were tested in this study. The experimental results indicate that the simplified method proposed in this paper can indeed be used to detect the depth of high-temperature damage in concrete. In addition, the experimental results show that under the same high-temperature exposure conditions, the depth of fire damage increases with a decrease in the water-cement ratio. This can be attributed to the higher thermal conductivity coefficient of concrete with a lower water-cement ratio.

Copper-nickel MOF-coated electrospun polyacrylonitrile membranes for Li–S batteries: Mitigating the shuttle effect and enhancing stability

Cu–Ni MOF nanoparticles were synthesized as coating materials for lithium–sulfur battery membranes, and the performance of batteries employing Cu–Ni MOF/PAN (CNMP) electrospinning membranes were examined. The modified membrane efficiently suppresses the shuttle effect, leveraging the synergistic catalysis and adsorption capabilities of the Cu–Ni MOF nanoparticles. The modified membrane exhibited relatively high porosity and outstanding electrolyte absorption capacity. The CNMP membrane battery demonstrated a remarkable first-cycle discharge capacity of 1529 mA h g⁻¹. The battery maintained an exceptional discharge capacity with 85.2 % retention and a minimal capacity decay rate of just 0.074 % per cycle after 200 cycles at 0.5 C. The capacity retention of the modified membrane battery remained at 74.6 % even after 2000 cycles at 2 C. The excellent performance of the modified membrane battery was due to the physical entrapment and strong chemical adsorption of lithium polysulfides by Cu–Ni MOF nanoparticles, significantly preventing the shuttle effect and facilitating rapid oxidation–reduction kinetics based on strong catalytic conversion.

Pressurized liquid extraction of sulfite for quantitation by capillary zone electrophoresis.

Sulfite is an additive used in shrimp processing to prevent discoloration. However, sulfite can cause health issues for sensitive consumers, making its monitoring necessary. Determining sulfite concentrations is complex because the Monier-Williams reference method is laborious and has low analytical throughput. Additionally, new techniques are needed to stabilize sulfite during the extraction process because this analyte undergoes rapid oxidation. A new method involving extraction and derivatization of sulfite with formaldehyde through automated pressurized liquid extraction (PLE), followed by quantitation by capillary zone electrophoresis with diode-array detector in indirect mode, was developed and optimized using multivariate planning. The PLE procedure was compared to another solid-liquid extraction method. The new method successfully stabilized and extracted sulfite from shrimp in few steps with adequate precision (CV<3.8%), producing extracts that were stable for 10 days. Recovery was satisfactory (97%-99%), and the limits of detection (4.6mgkg-1) and quantitation (15.4mgkg-1) were suitable for the intended purpose.

A Case Study on the Integration of Remote Sensing for Predicting Complicated Forest Fire Spread

Forest fires can occur suddenly and have significant environmental, economic, and social consequences. The timely and accurate evaluation and prediction of their progression, particularly the spread speed in difficult-to-access areas, are essential for emergency management departments to proactively implement prevention strategies and extinguish fires using scientific methods. This paper provides an analysis of models for predicting forest fire spread in China and globally. Incorporating remote sensing (RS) technology and forest fire science as the theoretical foundation, and utilizing the Wang Zhengfei forest fire spread model (1983), which is noted for its broad adaptability in China as the technical framework, this study constructs a forest fire spread model based on remote sensing interpretation. The model improves the existing model by adding elevation an factor and optimizes the method for acquiring certain parameters. By considering regional landforms (ridge lines, valley lines, and slopes) and vegetation coverage, this paper establishes three-dimensional visual interpretation markers for identifying hotspots; the orientation of the hotspots can be identified to simulate the spread of the fire uphill, downhill, in the direction of the wind, left-level slope, and right-level slope. Then, the data of Sentinel-2 and DEM were used to invert the fuel humidity and slope of pixels in the fire line areas. The statistical inversion data from pixels, which replaced fixed-point values in traditional models, were utilized for predicting forest fire spread speed. In this paper, the model was applied to the case of a forest fire in Mianning County, Sichuan Province, China, and verified using high-time-resolution Himawari-8 data, Gaofen-4 data, and historical data. The results demonstrate that the direction and maximum speed of fire spread for the fire lines in Baifen Mountai, Jiaguer Villageand, Muchanggou, Xujiabaozi, and Zhaizigou are uphill, 16.5 m/min; wind direction, 17.32 m/min; wind direction, 1.59 m/min; and wind direction, 5.67 m/min. The differences are mainly due to the locations of the fire lines, moisture content of combustibles, and maximum slopes being different. Across the entire fire line area, the average rate of increase in the area of open flames within one hour was 3.257 hm2/10 min (square hectares per 10 min), closely matching the average increase rate (3.297 hm2/10 min) monitored by the Himawari-8 satellite in 10 min intervals. In contrast, conventional fixed-point fire spread models predicted an average rate of increase of 3.5637 hm2/10 min, which shows a larger discrepancy compared to the Himawari-8 satellite monitoring results. Moreover, when compared to the fire spot monitoring results from the Gaofen-4 satellite taken 54 min after the initial location of the fire line, the predictions from the RS-enabled fire spread model, which integrates remote sensing interpretations, closely matched the actual observed fire boundaries. Although the predictions from the RS-enabled fire spread model and the traditional model both align with historical data in terms of the overall fire development trends, the RS-enabled model exhibits higher reliability and can provide more accurate information for forest fire emergency departments, enabling effective pre-emptive measures and scientific firefighting strategies.

Distribution of polycyclic aromatic hydrocarbons and carcinogenic risk assessment in street-barbecued foods in China

Street-barbecued foods, despite their popularity, produce carcinogenic polycyclic aromatic hydrocarbons (PAHs) such as benzo[a]anthracene (BaA), chrysene (Chr), benzo[b]fluoranthene (BbF), benzo[a]pyrene (BaP) due to incomplete charcoal combustion, direct food-fuel contact, and excessive heating. This study analyzed barbecued foods from high-traffic street vendors using high-performance liquid chromatography. Among five food categories (meat, vegetable, aquatic, starch, and soy products), eight foods exceeded China’s BaP limit (5 µg/kg) and twelve exceeded the EU limit (2 µg/kg). The highest BaP and PAH4 levels were found in barbecued beef and pork belly, respectively. Chr levels were notably high due to open flame exposure. Health risk assessments indicated fourteen foods posed elevated carcinogenic risks. This study highlights the necessity of consumption control to mitigate these risks and provides evidence for improving street food safety and dietary security.

A combination of covalent and noncovalent restricted‐intramolecular‐rotation strategy for supramolecular AIE‐type photosensitizer toward photodynamic therapy

AbstractPhotodynamic therapy (PDT) is a promising noninvasive method for targeted cancer cell destruction. Still, its effectiveness is often hindered by the aggregation‐caused quenching effect of organic photosensitizer (PS) in aqueous environments. Here, we have employed a combination of covalent and noncovalent restricted‐intramolecular‐rotation strategies to develop supramolecular PSs with aggregation‐induced emission (AIE) characteristics. Firstly, a water‐soluble octacationic molecular cage (1) with a bilayer tetraphenylethene (TPE) structure has been designed and synthesized, which minimizes intramolecular rotation of TPE moieties and achieves the single‐molecule‐level aggregation by the covalent restriction of intramolecular rotation (RIR) via molecular engineering synthesis. Compared with its single‐layer TPE analog, 1 exhibits superior efficiency in generating reactive oxygen species (ROS) including superoxide radical (O2−•) and singlet oxygen (1O2) upon white‐light irradiation. Subsequently, by forming a 1:4 host–guest complex (1@CB[8]4) between 1 and cucurbit[8]uril (CB[8]), O2−• generation can be further enhanced by the noncovalent RIR via the host–guest assembly. Additionally, 1@CB[8]4 as a photocatalyst promotes rapid oxidation of nicotinamide adenine dinucleotide (NADH) in water. Given its Type‐I ROS generation and catalytic activity for NADH oxidation, 1@CB[8]4 acts as a supramolecular AIE‐type PS to exhibit strong photo‐induced cytotoxicity upon white‐light irradiation under hypoxic conditions, showcasing its potential for synergistic PDT.

Energy-based damage assessment method for masonry walls under seismic and fire loads

The evaluation of the out-of-plane (OOP) behavior for infilled walls is a critical aspect of regional seismic and fire resilience assessment. This study presents a detailed finite element (FE) model that comprehensively captures the seismic and fire behaviors of masonry walls. The FE model incorporates key factors governing the thermo-mechanical behavior of masonry walls, including temperature-dependent material properties, nonlinearities in geometry and material, block cracking and crushing, and mortar damage. Then, an energy-based damage criterion is proposed based on the principle of energy conservation, leveraging the combined mixed fracture energy and internal energy of elements. In addition, this study defines the damage levels of masonry walls under OOP loading and fire and determines corresponding damage indices using the proposed energy-based damage criterion. This criterion is further compared with a stiffness-based damage criterion. Finally, the proposed damage assessment method is employed to evaluate the damage evolution of infilled walls under seismic, fire and post-earthquake fire scenarios, and to conduct a fragility analysis. The results demonstrate a high degree of agreement between the predicted and measured damage states of masonry walls under seismic and fire loads. More severe seismic damage does not always result in diminished fire resilience. Evaluating post-earthquake fire damage requires considering the impact of displacement directions caused by earthquakes and fires.

Controllable mechanism of hazardous jarosite transformation into recyclable hematite in the leaching solution of secondary zinc oxide powder

The controlled synthesis of recyclable hematite in the leaching solution of secondary zinc oxide powder is an urgent problem in the chemical industry and metallurgy fields. In this paper, the effects of the temperature, agitation speed, and seed addition on the contents of iron, sulfur, potassium, sodium, and zinc in the iron removal residues, as well as the iron concentration in the supernatant after iron removal were systematically studied. In addition to the temperature control already reported, we found that the agitation speed can also control the transformation between jarosite and hematite phases. The content of jarosite in the residues can be effectively controlled by adjusting the agitation speed, thereby significantly improving the quality of hematite product, as indicated by SEM-EDS and XRD results. Under temperature of 185 °C, an agitation speed of 500 rpm, and a seed addition of 15 g/L, the iron, sulfur and zinc contents in the filter residues and the iron concentration in the supernatant were 59%, 3.22%, 0.92%, and 4.182 g/L, respectively. Kinetic studies show that the rapid oxidation kinetics is not conducive to the formation of high-quality hematite products. These results can directly guide the process of transformation of harmful jarosite into recyclable hematite from the leaching solution of secondary zinc oxide powder, which is of great practical significance for the controlled and waste-free removal of iron from aqueous solutions in the chemical industry and metallurgy fields.

Catalytic oxidation of Mn(II) in the co-presence of Fe(II) by free chlorine: significance of in situ formed Mn(II)-doped Fe(III) oxides

Fe(II) and Mn(II) are abundant in groundwater and require operationally simple and efficient method to remove in drinking water treatment. The rapid oxidation of Mn(II) is essential in water treatment. This study investigates the efficiency of Mn(II) oxidation by free chlorine in the presence of Fe(II). The results demonstrate that the presence of Fe(II) significantly accelerates the oxidation rate of Mn(II) by free chlorine under neutral and alkaline conditions. The rapid oxidation of Fe(II) by free chlorine and the presence of Mn(II) promote the formation of in situ Mn(II)-doped ferrihydrite. Kinetic modeling and characterization of Fe(III) oxides confirm that the heterogeneous catalytic effect of the Mn(II)-doped ferrihydrite, rather than manganese oxides or their coupled catalytic effect, is responsible for the enhanced oxidation rates. The doped Mn(II) substitutes the tetrahedral Fe(III) ions in the ferrihydrite, introducing additional negative charges at the doped sites. The increased charge enhances Mn(II) adsorption and lowers its redox potential, thereby accelerating Mn(II) oxidation rate through direct electron transfer with adjacent free chlorine. Additionally, the lepidocrocite formed by the reaction between Fe(II) and dissolved oxygen significantly impedes the catalytic performance. These findings provide new insights into the catalytic co-oxidation mechanism of Fe(II) and Mn(II), and help the optimization of water treatment engineering practices.

Assessment of indoor air pollution in causing respiratory illness among women residing in rural areas of Mysuru

Introduction: The use of inefficient and harmful fuels and technology within and outside the home is the primary cause of indoor air pollution. Approximately 2.4 billion people on the planet still cook over open flames and inefficient stoves using solid fuels and kerosene. The availability of cleaner cooking options varies more in rural than in metropolitan settings. Therefore, there is a need to determine the prevalence of indoor air pollution among rural women, its association with respiratory disorders, and the frequency of respiratory illnesses among rural women residing in houses with or without indoor air pollution. Materials and methods: This analytical cross-sectional study was done for a period of six months from June to November 2020. The study conducted in 210 households living in the rural field practice areas of JSS Medical College, Mysuru. For the selection of villages, a multistage random sampling technique was used. Three villages are selected from the rural setting: Suttur, Hadinaru, and Kadakola. The households were included by probability proportionate to the size sampling technique. Pre-tested, semi-structured, phase and content validated questionnaires were used to obtain the details on socio-demographic characteristics, meter values of indoor air pollutants like Particulate Matters (PM1, PM2.5, PM10) and Volatile Organic Compounds (VOCs), respectively with the factors affecting respiratory illness and the episodes of the illness. Data was entered in Microsoft Excel and analyzed using descriptive and inferential statistics using SPSS V.26. Results: The prevalence of indoor air pollution in the present study was 13.3%. In the homes of rural women, there was a statistically significant variation in the concentration of the three particulate matter sources that cause indoor air pollution. Additionally, among the women living in rural families, there was a statistically significant difference in the concentration of PM10 that caused respiratory disease. Conclusion: The current study demonstrated the higher concentrations of pollutants such as PM10, PM2.5, and PM1.0, as well as their significant relation with indoor air pollution in rural families. To prevent indoor air pollution and its health risks, clean energy must be used for household needs.

Interactive impacts of organic-inorganic modifiers on surface characteristics of Cu+-doped activated carbon for stable CO-adsorptive separation from CO2

Conventional Cu+-doped activated carbon (C) materials are problematic in carbon monoxide (CO)-selective adsorption from carbon dioxide (CO2) due to their CO2-friendly surface basicity and microporosity. In this study, boehmite (AlOOH) film modified-carbon composite (AlC) was hydrothermally synthesized to dope with 30 wt% Cu+ ions by the impregnation-calcination method. The functional hydroxyl groups of Boehmite behaved as metallic anchoring sites for better Cu+ ion dispersion, enhancing the CO adsorption uptake to 38.84 cm3/g at 25 °C and ∼ 100 kPa in isotherm analysis. Additionally, the improved Lewis acidity of AlC surface interface together with pore widening impact reduced the CO2 uptake to 14 cm3/g, around half that of Cu+-doped activated carbon, by undergoing Lewis acid-acid repelling interaction between boehmite film and CO2. However, to address rapid oxidation of Cu+ ions in the hygroscopic AlC structure, iron (II) chloride (FeCl2) surface modification on the Cu+-doped AlC composite created a Fe3+-Cu+ bimetallic interface with high Cu+ immobilization, enriching the CO adsorption stability to 92 % even after 30 day-air exposure. Noticeably, pre-complexation of FeCl2 with thiourea (NH2CSNH2) before its dispersion over the doped Cu+ ions led to distinct Cu+ stabilization mechanisms without bimetallic redox interaction. This involves developing auto-redoxable iron (II) sulfides as barrier coatings for Cu+ species against oxidation and raising the Cu2+ reducibility via cyanide-ligands of thiourea. These combined preservation effects for Cu+ ions ensured CO adsorption stability of 91 %, underlining higher CO adsorption uptake (39.38 cm3/g) and CO/CO2 selectivity (67.49 at 0.2 kPa and 3.09 at ∼ 100 kPa) than modification effects of boehmite and FeCl2.

Study on pedestrian evacuation simulation model considering group behavior

As a crowded place on the university campus, the cafeteria inevitably has many safety hazards, such as fire accidents caused by open flames and large appliances, stampede accidents caused by overcrowding during peak dining hours, etc. Therefore, studying pedestrian evacuation in university campus cafeterias is particularly necessary. Pedestrians on campus mostly travel in groups. Previous studies mainly used continuous models to discuss pedestrian group evacuation behavior. In this study, based on the cellular automaton pedestrian evacuation simulation model, the floor field calculation method was improved. A cellular automaton pedestrian evacuation simulation model considering group behavior was established and applied to the evacuation scenario of students in a university campus cafeteria. The study found that under the different group configurations, the pedestrian ratios, and the pedestrian densities, the pedestrian evacuation efficiency had significant differences. The results showed that when the different group configurations existed in the scenario, the higher the proportion of the pedestrians with three-person front-to-back group configurations, the higher the evacuation efficiency. When only one type of the group configuration existed in the scenario, at low pedestrian density, the evacuation efficiency of the individual pedestrian groups was higher compared to the other six group configurations. While at high pedestrian density, the evacuation efficiency of the three-person front-to-back group configurations was higher. These findings provided important references for pedestrian evacuation in university campus cafeterias and provided insights for the simulation research of group pedestrian evacuation models, contributing to enhancing campus safety management and ensuring the safety of teachers, students, and staff.

Processing of banana mangará: Microbiological evaluation and development of preserves and appetizers with a focus on sensory qualities and gastronomic applications

Banana inflorescences, known as mangará, are non-conventional edible plants (NCEP) found in banana cultivation. Despite their nutritional potential, they are underutilized due to rapid oxidation and tannins, which cause unpleasant sensory characteristics. This research aimed to process mangará to maintain its microbiological, physical, and sensory quality for food applications. Initially, mangará was physically characterized and treated to reduce oxidation and tannin taste. Three types of preserves were developed: water-based (WMP), vinegar-based (VMP), and pickle-based (PMP). These preserves underwent physicochemical and microbiological characterization and sensory evaluation by gastronomy professionals. WMP was also used to prepare appetizers (mangará caponata and relish antipasti), subjected to sensory analysis. PMP showed higher titratable acidity, soluble solids, and protein content (2.76 mg; 4.0 ± 0.1 °Brix; 0.45 ± 0.01%). Only VMP and PMP met the pH requirement (below 4.5). All formulations had low lipid content and were microbiologically safe. Microbiological evaluations confirmed the absence of pathogenic bacteria. Colorimetric analysis showed no difference in the b∗ value between samples. Similar antioxidant activity was observed for VMP (10.01 μmol TE/mL) and PMP (7.87 μmol TE/mL). Sensory evaluation indicated that all samples were accepted, with scores ranging from “slightly liked” to “liked very much”. Mangará caponata was the most preferred appetizer. The study demonstrated the feasibility of processing mangará into microbiologically safe and sensory-pleasing preserves and appetizers, highlighting their potential for innovative culinary uses. Further research should explore processing methods' scalability and preserve long-term stability.

Temperature-Dependent Oxidation Behavior of Silicon Carbide Surface: Reactive Molecular Dynamics Simulations.

The high-temperature oxidation mechanism of silicon carbide (SiC) is crucial for designing thermal protection systems in aircraft. This study explored the oxidative chemical reaction processes and mechanism on SiC surface and interfaces within the temperature range of 300-2300 K by using reactive molecular dynamics simulation. The oxygen impact on the silica (SiOx) growth of the SiC surface was analyzed, which shows a progressive increase of silica thickness. The simulation results indicated that the oxidation process of SiC was a typical passive oxidation mechanism. With the environmental temperature rising and oxygen impact, the increase of oxidation thickness on the SiC surface undergoes three oxidizing reaction processes: little chemical adsorption of oxygen molecules on the initial surface, rapid oxidation of silicon and carbon, and dramatic oxidation of the interface between the oxidation layer and SiC. Additionally, this work studied the mechanism of oxidation thickness growth and chemical diffusion of oxygen. The oxidation rate is weakened according to the oxygen atom diffusion barrier effect of silica repulsion. Moreover, the kinetic parameters were statistically calculated by fitting the growth of Si-O bonds and their reaction rate constants. Subsequently, the activation energy and pre-exponential factors were derived by using the Arrhenius equation to model the chemical reaction kinetics of the thermal oxidation process. The chemical reaction behaviors of the two stages could be concluded as follows: (i) in stage I, the initial oxidation is reaction rate limiting; (ii) in stage II, SiC oxidation is limited by both the oxidation reaction rate and the oxygen diffusion coefficient of the oxidation layer. The activation energy of stage II increased compared with stage I due to the oxygen atoms diffusion barrier between the oxidation layers. This study on the oxidation and ablation mechanism of the SiC surface at the atomic scale would provide insight into understanding thermal oxidation behavior and the design of ceramic materials.

High stability and reactivity of porous calcium tartrate supported nano zero-valent iron in aerobic environment and alkaline wastewater

Nano zero-valent iron (nZVI) has remarkable reactivity, but its practical application is severely hindered by its easy aggregation and rapid oxidation after exposure in air. In this study, spherical porous calcium tartrate (CaTr) was synthesized with ultrasound technology and used to support nZVI. It was found that the as-obtained nZVI@CaTr was highly stable and reactive in oxygen-rich water under neutral/alkaline conditions. In the pH range of 4–9, the degradation efficiency of p-nitrophenol (PNP, 50 mg/L) by nZVI@CaTr7 exceeded 98.1 %. Importantly, nZVI@CaTr could be stored in air for a long time without inert gas protection. After 60 days and 120 days of air exposure, the removal efficiency of PNP still reached 83.3 % and 63.3 %, which was 2.8 and 9.7 times that of bare nZVI, respectively. Such an excellent performance could be attributed to two reasons: (i) spherical CaTr effectively inhibited the oxidation and aggregation of nZVI by favorable interactions with nZVI, and (ii) the abundant functional groups on the surface of CaTr acted as electronic mediators to significantly promote charge transfer between nZVI (electron donor) and PNP (electron acceptor). Therefore, cheap, air stable and highly effective nZVI@CaTr7 provided a potential application prospect for the degradation of environmental pollutants in aerobic environment and alkaline wastewater.