Oxygen accumulation and associated dangers in rescue helicopters.

BACKGROUND: At the time of the COVID-19 pandemic, devastating incidents increased due to frequent oxygen administration to patients. The dangers associated with the use of oxygen, especially through local enrichments and formation of "oxygen clouds", have been well understood for years. Nevertheless, dramatic incidents continue to occur, since fire hazard increases exponentially with oxygen concentrations above 23%. Rescue helicopters are at a particular high risk, because of technical reasons such as oxygen use in a very small space, surrounded by kerosene lines, electronic relays and extremely hot surfaces. METHODS: In this study three different sized rescue helicopter models (Airbus H135, H145 and MD902) were examined. Oxygen enrichment in the cabin was measured with an oxymeter during a delivery rate of 15 l/min constant flow for 60 min. Furthermore, the clearance of the enriched atmosphere was tested in different situations and with different ventilation methods. To make the airflow visible, a fog machine was used to fill the helicopter cabin. RESULTS: Oxygen accumulation above 21% was detected in every helicopter. After 10-15 min, the critical 23% threshold was exceeded in all three aircrafts. The highest concentration was detected in the smallest machine (MD902) after 60 min with 27.4%. Moreover, oxygen clouds persisted in the rear and the bottom of the aircrafts, even when the front doors were opened. This was most pronounced in the largest aircraft, the H145 from Airbus Helicopters. Complete and rapid removal of elevated oxygen concentrations was achieved only by cross-ventilation within 1 min. CONCLUSIONS: Oxygen should be handled with particular care in rescue helicopters. Adapted checklists and precautions can help to prevent oxygen accumulation, and thus, fatal incidents. To our knowledge, this is the first study, which analyzed oxygen concentrations in different settings in rescue helicopters.

Study on combustion characteristics of glass fiber/phenolic resin composites.

In order to study the combustion characteristics of glass fiber/phenolic resin composites, a conical calorimeter was used to explore the combustion characteristics of glass fiber/phenolic resin composites in an aircraft frame under different thermal radiation intensities, and the fire hazard of the materials was evaluated by evaluation index, and the limiting oxygen index at different temperatures was explored by combining the high temperature oxygen index meter. The test results show that when the ambient temperature increases from 20 °C to 220 °C, the limiting oxygen index first increases from 86.6 % to 93.7 %, and then decreases to 84.4 %. The oxygen consumption and CO2 release increase with the increase of thermal radiation intensity during combustion, and the release of CO decreases with the increase of thermal radiation. The heat release rate curve of the test material has only 1 enhancement peak. The heat radiation intensity increased from 50 kW/m2 to 70 kW/m2, and the peak heat release rate of the test material combustion increased from 64.7 kW/m2 to 100.7 kW/m2. The rate of mass loss of materials accelerates with the increase of thermal radiation intensity; As the intensity of thermal radiation increases, the fire hazard of the material increases.

Flammability, Toxicity, and Microbiological Properties of Polyurethane Flexible Foams.

The aim of the research was to investigate the influence of calcium phosphinate (HPCA) and aluminum phosphinate (HPAL) in synergistic systems with organophosphorus compounds, i.e., diphenylcresyl phosphate (CDP) and trichloropropyl phosphate (TCPP), on the thermal stability, flammability, smoke density, and emission of toxic gases during the thermal decomposition of polyurethane (PUR) foams. Thermogravimetric analysis (TGA), along with cone calorimetry and microcalorimetry, were used to assess the influence of fillers on the thermal stability and flammability of PUR foams. The analysis of toxic gas products was performed with the use of a coupled TG-gas analyzer system. The optical density of gases was measured with the use of a smoke density chamber (SDC). The obtained results showed an increase in thermal stability and a decrease in the flammability of the PUR composites. However, the results regarding smoke and gas emissions, as well as toxic combustion by-products, present ambiguity. On one hand, the applied flame retardant systems in the form of PUR-HPCA-CDP and PUR-HPCA-TCPP led to a reduction in the concentration of CO and HCN in the gas by-products. On the other hand, they clearly increased the concentration of CO2, NOx, and smoke emissions. Microbiological studies indicated that the obtained foam material is completely safe for use and does not exhibit biocidal properties.

Cage Nanofillers' Influence on Fire Hazard and Toxic Gases Emitted during Thermal Decomposition of Polyurethane Foam.

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.

Assessing wildfire impact on Trigonella elliptica habitat using random forest modeling.

Wildfires have a significant impact on ecosystems worldwide, especially on the degradation of arid and semi-arid rangelands. This research focuses on assessing the effects of wildfires on the habitat of Trigonella elliptica, a valuable herb species found in the central rangelands of Iran. To achieve this, the Random Forest (RF) algorithm has been deployed to predict T. elliptica habitat and fire hazard using socio-environmental variables in Yazd province, Iran. 225 fire points and 103 habitat locations were used for model training and testing. The IncNodePurity index and Probability Curves (PC) have been utilized to determine the influence of socio-environmental variables. The combination of the prediction maps of the habitat and wildfires pointed out the possible damage due to fire. The high performance of the RF model is confirmed by the area under the curve (AUC) and the true skill statistic (TSS) values (0.90 and 0.81 for the habitat; 0.92 and 0.82 for the wildfire). The importance assessment of variables revealed that elevation, slope, and precipitation are the most influential variables in the distribution of T. elliptica, while distance to roads, population density, and wind speed are the key factors affecting wildfire occurrence. In the final map, a comparison of different regions of T. elliptica habitat under fire hazard with fire-free habitats using Kruskal-Wallis and Dunn tests indicated that the fire hazard in the T. elliptica habitat is a serious concern. Since the areas with the highest fire hazard and the highest presence of T. elliptica cover approximately 2311.38 km2, neglecting these regions could lead to the gradual reduction of T. elliptica, and create conditions for secondary succession dominated by less valuable annual species. The findings of this study underscore the importance of implementing fire management strategies, protection projects, and continuous monitoring to ensure the safety and conservation of the T. elliptica habitat.

Cross-Linking Characteristics, Morphology, Dynamics, and Mechanical and Thermal Properties of Polychloroprene/Polybutadiene/Nano-Zinc (CR/BR/nZn) Compositions with Reduced Fire Hazard.

The properties of unconventional blends of crystallizable and thermo-cross-linkable polychloroprene (CR) with polybutadiene (BR) were investigated in this study. The compositions were prepared using the method of reactive processing and cross-linking in the presence of nano-sized zinc (nZn). The purpose of the research was to assess the efficacy of nano-zinc as a curing agent of polychloroprene and polybutadiene (CR/BR) composites and to obtain rubber goods characterized by increased flame resistance. The blends were filled with nano-silica (aerosil) and fillers of natural origin (chalcedonite or silitin). The cross-linking process was characterized by determining the kinetics curves, the equilibrium swelling, and the Mooney-Rivlin elasticity constants. The morphology of the vulcanizate surface was specified by scanning electron microscopy (SEM). The dynamic and mechanical properties, flammability, and toxicity of gaseous substances involved in thermal decomposition were determined. Mass changes and thermal effects were studied using simultaneous thermal analysis (STA). It was confirmed that nano-zinc is an efficient curing agent for the polychloroprene and polybutadiene compositions, with a satisfactory degree of cross-linking (αc = 0.10, CRI = 4.11 min-1), good mechanical strength (TSb = 5 MPa), satisfactory tear resistance (Ts = 2.9 N/mm), and very high flame resistance (OI = 30%, HRRmax = 283 kW/m2). Filled products could be used as non-combustible materials, confirming the low fire hazard (1/tflashover = 3.5-6.4 kW/m2∙s). The most effective filler of the tested composites was nano-sized silica.

Initial exploration on potential fire hazards detection from coal spontaneous combustion applied by acoustic wave.

Coal spontaneous combustion often wastes resources and causes environmental pollution. Rapid and accurate identification of high temperature areas in coal is essential to reducing such combustion and environmental pollution. The acoustic thermometry method has the benefits of large temperature measurement space, non-contact, and high interference resistance. Determining the attenuation characteristics of acoustic waves in loose coal is the basis and premise for realizing acoustic temperature measurement. Four types of bituminous coal were scanned by computer tomography equipment. A self-designed acoustic attenuation test device was used to test coal samples under different temperatures and particle sizes. The study result demonstrates that the distribution characteristics of loose coal voids are mainly related to the particle size. The smaller the particle size range, the more uniform the void distribution. As the size of the coal particles increases, the voids become larger. The acoustic attenuation coefficients of four coal samples showed an increasing trend as frequency increased. The influence of coal particle size distribution on the acoustic attenuation coefficient was greater than that of temperature and metamorphic degree. The peak values of coal sound attenuation for different particle sizes were around 400, 700, 1100, and 1600 Hz. This indicated that the distribution of voids was the main factor affecting the propagation of acoustic waves. By analysing the attenuation mechanism of the acoustic wave in loose coal, the attenuation of acoustic temperature measurement signal was caused by the combined effect of loose coal on acoustic wave absorption and scattering. The study results provide theoretical support for the realization of acoustic wave detection of high temperature point in loose coal spontaneous combustion.

Fuel reduction burning reduces wildfire severity during extreme fire events in south-eastern Australia.

Extreme fire events have increased across south-eastern Australia owing to warmer and drier conditions driven by anthropogenic climate change. Fuel reduction burning is widely applied to reduce the occurrence and severity of wildfires; however, targeted assessment of the effectiveness of this practice is limited, especially under extreme climatic conditions. Our study utilises fire severity atlases for fuel reduction burns and wildfires to examine: (i) patterns in the extent of fuel treatment within planned burns (i.e., burn coverage) across different fire management zones, and; (ii) the effect of fuel reduction burning on the severity of wildfires under extreme climatic conditions. We assessed the effect of fuel reduction burning on wildfire severity across temporal and spatial scales (i.e., point and local landscape), while accounting for burn coverage and fire weather. Fuel reduction burn coverage was substantially lower (∼20-30%) than desired targets in fuel management zones focused on asset protection, but within the desired range in zones that focus on ecological objectives. At the point scale, wildfire severity was moderated in treated areas for at least 2-3 years after fuel treatment in shrubland and 3-5 years in forests, relative to areas that did not receive fuel reduction treatments (i.e., unburnt patches). Fuel availability strongly limited fire occurrence and severity within the first 18 months of fuel reduction burning, irrespective of fire weather. Fire weather was the dominant driver of high severity canopy defoliating fire by ∼3-5 years after fuel treatment. At the local landscape scale (i.e., 250 ha), the extent of high canopy scorch decreased marginally as the extent of recently (<5 years) treated fuels increased, though there was a high level of uncertainty around the effect of recent fuel treatment. Our findings demonstrate that during extreme fire events, very recent (i.e., <3 years) fuel reduction burning can aid wildfire suppression locally (i.e., near assets) but will have a highly variable effect on the extent and severity of wildfires at larger scales. The patchy coverage of fuel reduction burns in the wildland-urban interface indicates that considerable residual fuel hazard will often be present within the bounds of fuel reduction burns.

Effect of Hybrid Filler, Carbon Black-Lignocellulose, on Fire Hazard Reduction, including PAHs and PCDDs/Fs of Natural Rubber Composites.

The smoke emitted during thermal decomposition of elastomeric composites contains a significant number of carcinogenic and mutagenic compounds from the group of polycyclic aromatic hydrocarbons, PAHs, as well as polychlorinated dibenzo-p-dioxins and furans, PCDDs/Fs. By replacing carbon black with a specific amount of lignocellulose filler, we noticeably reduced the fire hazard caused by elastomeric composites. The lignocellulose filler reduced the parameters associated with the flammability of the tested composites, decreased the smoke emission, and limited the toxicity of gaseous decomposition products expressed as a toximetric indicator and the sum of PAHs and PCDDs/Fs. The natural filler also reduced emission of gases that constitute the basis for determination of the value of the toximetric indicator WLC50SM. The flammability and optical density of the smoke were determined in accordance with the applicable European standards, with the use of a cone calorimeter and a chamber for smoke optical density tests. PCDD/F and PAH were determined using the GCMS-MS technique. The toximetric indicator was determined using the FB-FTIR method (fluidised bed reactor and the infrared spectrum analysis).

The Morphology, Mechanical and Dynamic Properties, Fire Hazard and Toxicity of Chloroprene and Butadiene Rubber Composites Cross-Linked with Zinc.

This paper presents the influence of zinc on the cross-linking process, mechanical and dynamic properties, morphologies and balance of thermal degradation of blends containing chloroprene rubber (CR) and butadiene rubber (BR). The novel aspect of this research is a comprehensive approach presenting a new curing agent for the CR/BR blends to increase their cross-linking density and final properties, including non-flammability and low fire hazard. This is due to the need to find an alternative to zinc oxide, which is the standard curing agent for chloroprene rubber. The regulations of the European Union enforce a significant limitation on the use of this compound in elastomer technology, due to its harmful effect on aquatic organisms. In this paper, the CR/BR composites were cured with zinc and filled with natural silica fillers (sillitin or chalcedonite) or synthetic silica filler (aerosil). The investigation focused on the morphology characterization of the obtained compounds, their cross-linking degree, swelling, mechanical and dynamic properties, fire hazard and toxicity. The structure of cured CR/BR blends was characterized via scanning electron microscopy (SEM). The fire resistance studies were performed using cone calorimetry or oxygen index methods, whereas toxicity tests were performed with the use of the FB-FTIR (fluidized bed reactor coupled with FTIR analyzer) method. The results showed that obtained CR/BR products were characterized by satisfactory final properties. The properties determined by the oxygen index and cone calorimetry methods, including the behaviors of the tested CR/BR vulcanizates in fire conditions, showed that the produced compounds were characterized by a low fire hazard and can be classified as non-combustible rubber products. However, the toxicity of the decomposition products, determined at 450, 550 and 750 °C, was very high.

A DOPO-Based Compound Containing Aminophenyl Silicone Oil for Reducing Fire Hazards of Polycarbonate.

A novel P/N/Si-containing flame retardant (marked as DASO) was synthesized through an Atherton-Todd reaction between 9,10-dihydro-9-oxa-10-phospha-phenanthrene-10-oxide and aminophenyl silicone oil, and further used for reducing fire hazards of polycarbonate (PC). The chemical structure of DASO was verified via FTIR, 1H, and 31P NMR. Upon the incorporation of 2 wt% DASO, the FRPC composite achieved a high limiting oxygen index (LOI) of 32.2% and a desired UL-94 V-0 rating. In this case, the peak heat release rate (PHRR) and total smoke production (TSP) were reduced by 26% and 44% as compared with the pure PC, respectively. The improved fire safety contributed to the flame retardant roles of DASO in both the condensed phase and gas phase. The presence of DASO promoted the formation of dense and highly graphited char layer in the condensed phase, and released non-combustible gases and phosphorus-containing radicals in the gas phase. Furthermore, the FRPC composites displayed comparable elongation at break but a slightly reduced tensile and impact strength.

Electric vehicle fire risk assessment framework using Fault Tree Analysis.

Background: In the near future, the rapid adoption of electric vehicles is inevitable, driven by environmental concerns and climate change awareness. However, this progressive trend also brings forth safety concerns and hazards, notably regarding the risk of EV fires, which have garnered significant media attention. This necessitates the need to study for comprehensive fire risk assessment strategies aimed at preventing and mitigating such incidents. Methods: This study presents a framework for assessing fire risks in EVs using Fault Tree Analysis (FTA). By integrating disparate data sources into a unified dataset, the proposed methodology offers a holistic approach to understanding potential hazards. The study embarked on a comprehensive exploration of EV fire causes through qualitative FTA. Results: Through this approach, the work discerned five major causes: human factors, vehicle factors, management factors, external factors, and unknown factors. Using a meticulous weighted average approach, the annual EV fire frequency for each country was deduced, revealing an average annual EV fire rate of 2.44 × 10 -4 fires per registered EV. This metric provides a significant benchmark, reflecting both the probability and inherent risk of such incidents. However, uncertainties in data quality and reporting discrepancies highlight the imperative of continued research. Conclusions: As EV adoption surges, this study underscores the importance of comprehensive, data-driven insights for proactive risk management, emphasizing the necessity for vigilant and adaptive strategies. The findings emphasize the pivotal role of this assessment in shaping response strategies, particularly for first responders dealing with EV fires. In essence, this research not only elevates the understanding of EV fire risks but also offer a foundation for future safety measures and policies in the domain.

[Use of high-flow oxygen treatment in the emergency medical service: what are the dangers for users from the perspective of occupational and fire protection?] / Anwendung von "High-flow"-Sauerstoff-Therapie im Rettungsdienst: Welche Gefahren ergeben sich für Anwender aus der Perspektive des Arbeits- und Brandschutzes?

INTRODUCTION: The administration of high concentrations of oxygen may harm patients or paramedics by increasing the probability of fire. The presented work investigated the effect of oxygen applied via high flow in different concentrations and flow rates on environmental oxygen concentrations in the patient compartment of an ambulance. RESULTS: Environmental oxygen concentrations increased rapidly over time and oxygen is stored in blankets and clothes over a long period. Simulation in a fire laboratory showed that also in high oxygen concentration settings fire needs a flame or temperatures above 300 °C. Sparks alone were not able to start a fire. CONCLUSION: Ventilation of patient compartment and clothes with ambient air are mandatory to reduce dangerous oxygen concentrations in transport of patients on high-flow oxygen treatment.

Safety at waste and recycling industry: Detection and mitigation of waste fire accidents.

In this study, NASA's VIIRS (Visible Infrared Imaging Radiometer Suite) fire hotspots and data of the Swedish Civil Contingencies Agency (MSB), collected between 2012 and 2018, was integrated to characterize waste fire incidents that were detected by VIIRS and reported to MSB (DaR), detected by VIIRS but not reported to MSB (DbNR) and that are reported to MSB but not detected by VIIRS (RbND). Results show that the average number of open waste fire incidents per million capita per year (AFIPMC) in Sweden, for the period 2012-2018, ranges from 2.4 to 4.7. Although a weak correlation exists (r = 0.44, P = 0.1563, one tailed) between years and number of fire incidents (MSB + VIIRS fires), a continuous increase in number of fire incidents was recorded between 2014 and 2018. It is concluded that the use of satellite data of fire anomalies, in-combination with the use of incident reports, will help in formalizing more reliable and comprehensive waste fire statistics. Another focus area of the article is to consolidate the recommendations and routines for safe storage of waste and biofuels and to present the lessons that can be learnt from past fire incidents. The article also discusses the technical, political, economic, social, and practical aspects of waste fires and provide a baseline for future research and experimentation.

Effects of Basalt and Carbon Fillers on Fire Hazard, Thermal, and Mechanical Properties of EPDM Rubber Composites.

Due to growing restrictions on the use of halogenated flame retardant compounds, there is great research interest in the development of fillers that do not emit toxic compounds during thermal decomposition. Polymeric composite materials with reduced flammability are increasingly in demand. Here, we demonstrate that unmodified graphene and carbon nanotubes as well as basalt fibers or flakes can act as effective flame retardants in polymer composites. We also investigate the effects of mixtures of these carbon and mineral fillers on the thermal, mechanical, and rheological properties of EPDM rubber composites. The thermal properties of the EPDM vulcanizates were analyzed using the thermogravimetric method. Flammability was determined by pyrolysis combustion flow calorimetry (PCFC) and cone calorimetry.

BIM and Computer Vision-Based Framework for Fire Emergency Evacuation Considering Local Safety Performance.

Fire hazard in public buildings may result in serious casualties due to the difficulty of evacuation caused by intricate interior space and unpredictable development of fire situations. It is essential to provide safe and reliable indoor navigation for people trapped in the fire. Distinguished from the global shortest rescue route planning, a framework focusing on the local safety performance is proposed for emergency evacuation navigation. Sufficiently utilizing the information from Building Information Modeling (BIM), this framework automatically constructs geometry network model (GNM) through Industry Foundation Classes (IFC) and integrates computer vision for indoor positioning. Considering the available local egress time (ALET), a back propagation (BP) neural network is applied for adjusting the rescue route according to the fire situation, improving the local safety performance of evacuation. A campus building is taken as an example for proving the feasibility of the framework proposed. The result indicates that the rescue route generated by proposed framework is secure and reasonable. The proposed framework provides an idea for using real-time images only to implement the automatic generation of rescue route when a fire hazard occurs, which is passive, cheap, and convenient.

Fire-susceptibility mapping in the natural areas of Iran using new and ensemble data-mining models.

Fires have increased in northeastern Iran as its semi-arid climate landscape is desiccated by human activities. To combat fire outbreaks in any region, fire susceptibility must be mapped using accurate and efficient models. This research mapped fire susceptibility in the forests and rangelands of Golestan Province in northeastern Iran using new data-mining models. Fire effective factors, including elevation, slope angle, annual mean rainfall, annual mean temperature, wind effect, topographic wetness index (TWI), plan curvature, distance to river, distance to road, and distance to village were obtained from several sources. The relative importance of each variable was determined using a random-forest algorithm. Fire-susceptibility maps were produced in R 3.0.2 software using GAM, MARS, SVM algorithms, and a new ensemble of the three models: GAM-MARS-SVM. The four fire-susceptibility maps were validated using the area under the curve. The results show that the distance to the village, annual mean rainfall, and elevation were of greatest importance in predicting fire susceptibility. The new GAM-MARS-SVM ensemble model achieved the highest precision of fire-susceptibility mapping. The fire-susceptibility map produced using the GAM-MARS-SVM ensemble model best detected the high fire risk areas in Golestan Province. The fire-susceptibility map produced by the ensemble model can be very useful for creating and enhancing management strategies for preventing fires, particularly in the higher-risk portions of Golestan Province.

Reducing fire and burn risk in the operating room-testing of a novel device.

BACKGROUND: Burn injury and operating room fires are significant risks for both surgical patients and staff. The purpose of this study was to examine the fire and burn risks associated with two types of fiberoptic light cables and evaluate the efficacy of a novel device in reducing the risk of these fire and burn injuries. METHODS: A 300-W light source was connected sequentially to two standard fiberoptic cables (Storz and Olympus). The distal ends were buried in, or rested on, standard operating room materials including a cotton green towel and a blue propylene drape to assess the risk of fire formation or burn injury. The Gloshield device was then attached to the ends of the cables and the experiment was repeated. Trials simulating improper use of the device were then conducted with the Gloshield device placed either too deep or too shallow on the end of the light cable. All trials were conducted for a maximum of 10 min or until a positive result (burn or fire) was achieved. Trials were conducted in room air or with supplemental 100% oxygen and repeated for accuracy. RESULTS: Both the Storz and Olympus fiber optic cables were capable of producing burns in standard operating room towels and drapes in control trials. The Gloshield device prevented thermal injury when properly attached in all conditions. Improper use trials demonstrated that the device may be ineffective when not applied properly. CONCLUSIONS: The Gloshield device is effective in reducing the risk of thermal burn injury by protecting the distal ends of endoscopic light cables from operating room materials. However, the device needs to be attached appropriately in order to provide protective benefits.

Fully bio-based, low fire-hazard and superelastic aerogel without hazardous cross-linkers for excellent thermal insulation and oil clean-up absorption.

Elastic biomass aerogels have attracted widespread attention but are seriously hindered by environmentally unfriendly cross-linkers and fire hazards for functional applications. This study outlines the fabrication of a fully bio-based, low fire-hazard and superelastic aerogel without any cross-linkers for excellent thermal insulation and oil absorption, via creating highly oriented wave-shaped layer microstructures and subsequently depositing nonflammable siloxane coating on the surface of the aerogel skeleton. The resultant environmental-safety aerogel showed the combined advantages of anisotropic super-elasticity, hydrophobicity, low density and high flame retardancy (limiting oxygen index value of 42%, UL-94 V-0 rating, and extremely low heat release), thus leading to many benefits for solving environmental hazards. For instance, this fire-safety biomass aerogel can be used as the high-performance thermal insulator with low thermal conductivity and high shielding efficiency. The aerogel also exhibited a great selectively oil clean-up absorption with a high absorption capacity of 117 times its own weight and excellent recyclability. Especially, due to the highly oriented microstructures, the aerogel as a filter showed the fastest separation rates of oil/water mixture (flux rate of 145.78 L h-1 g-1) ever reported. Such a method of preparing super-elastic biomass aerogels will provide new insights into their multifunctional applications with high environmental safety.

Effects of Overlap Length on Flammability and Fire Hazard of Vertical Polymethyl Methacrylate (PMMA) Plate Array.

Polymethyl methacrylate (PMMA) plates are widely used in buildings or factories for natural lighting. Commonly PMMA plates are installed as a discrete array. However, PMMA plates are very susceptible to fire. Therefore, experimental study on flammability and fire hazard of vertical PMMA plate array with different overlap length (D) was conducted in this work. The average flame height (Hf) increases first and then decreases with an increase in the overlap length, and reaches the maximum when D = 40 mm. The discrete flame spread speed (Vf) also rises first and then drops with the increase of D, which is mainly due to the heat transfer from the PMMA flame to the next plate. A model for predicting the flame spread rate of discrete PMMA array is established. The predicted results are consistent with experimental ones, with a predicted error smaller than 15%. The average temperature of flame zone rises first and then drops as D increases, reaching the maximum when D = 40 mm. This leads to the same changing trend of radiative heat flux. Results obtained in this work provide a reference for fire hazard evaluation and fire safety design of PMMA plates employed in buildings or industrial sites.