Burning Time Research Articles

521 Silk A Biological Dressing for Superficial Burns Treatment: Randomized Controlled Trial Versus Silver Sulfadiazine

Abstract Introduction Silver Sulfadiazine is currently the standard treatment for superficial second-degree burns. These burns are common and should not necessarily require hospital treatment. However, caretaking may become an issue: dressing technique is not always mastered by home health care nurses, their practical realization may be more difficult considering the surface to be treated; duration of care can also be too long and painful. We have evaluated the interest of a dressing based on natural silk with this indication. Methods In a preliminary study, we have compared SSD to silk dressing (S) in the treatment of 2nd degree burns. Following diagnosis, the topical to be used was determined by drawing of lots. The SSD associated with fatty gauze was applied and then covered with dry gauzes and bandages. Silk was applied directly on the lesion and then covered with dry gauzes and bandages. Dressings were changed every 48 hours. The SSD was changed with each dressing after cleansing the lesion with saline; the silk one was left in place until healing, only the dry gauzes and bandages were changed. Pain, duration of care and healing time were assessed. Results 80 patients were included 25 men, 15 women (7 to 83years) were treated with SSD; 22 men, 18 women (17 to 84 years) with silk. The average surface area treated was 5% in both groups (1% to 20% SSD) and (1% to 23% S). Pain (EVA) was evaluated between 3 and 4/10 for the SSD group and 0 to 2 for the S group. Dressing duration was 20-30 minutes for the SSD group and 10-15 minutes for the S group. The average healing time was 13 days for both groups. 2 complications, as infections , were observed in each group. Conclusions The flexibility of silk facilitates smooth application on all surfaces and localisations like SSD. Silk treatment has the same healing time as that obtained with SSD, i.e. the physiological healing time of 2nd degree superficial burns. Silk has allowed shorter treatments, because it is technically simple, and less painful as the lesion was never exposed to air. This allowed reduction of analgesics. A larger study should confirm that 2nd degree burns can be managed with silk dressing as outpatients, by home health care nurses, inexperienced in burns and even for larger surfaces and reduce the cost effective of the treatment and the need for painkillers. Applicability of Research to Practice immediate

112 Computer Adaptive Test Development of Preschool Life Impact Burn Recovery Evaluation

Abstract Introduction Measuring physical, psychological, and social outcomes following childhood burn injury is important to understand the impact of the burn. Condition-specific outcomes are highly relevant in assessments for purposes of gauging early growth and development through parent-reported outcome measures (PROMs). Item content in existing PROMs for preschool children is limited and often covers only one construct. Computer adaptive tests (CATs) with advanced psychometric artificial intelligence technologies minimizes respondent burden and enables the creation of a comprehensive condition-specific instrument. This project developed a parent-reported CAT (Preschool1-5 Life Impact Burn Recovery Evaluation (PS-LIBRE1-5) Profile) to measure relevant outcomes after burn injuries in children aged one to under six years. Methods Responses to the field-tested PS-LIBRE1-5 Profile (188 items) were measured on a scale of frequency or ability levels. Scores were coded from 0 to 4 where higher scores reflected better functioning. Factor analysis and Partial Credit Models identified the items retained in the final item bank of each scale. Differential item functioning (DIF) determined if subgroups of burn survivors at the same ability level demonstrated different probabilities of responses. CAT simulations were conducted to estimate the mean score of each scale. The simulated CAT score and full item bank scores were compared based upon the score range, ceiling and floor effects, and marginal reliabilities. Results The child mean age was 3.0 + 1.5 years (n = 498), with primarily mothers (83%) responding. Average burn size and time since burn injury were 4.2% TBSA and 1.1 years, respectively. Analysis resulted in eight scales: Physical (27 items), Communication and language (20 items), Emotional wellbeing (16 items), Mood (11 items), Anxiety (13 items), Peer acceptance (7 items), Play (8 items), and Peer relations (9 items). Severe DIF by ‘age at survey completion’ was shown in 13 items. Ceiling effects were acceptable at < 14%. A CAT was created with the exception of four of the scales (Peer acceptance, Play, Mood, and Anxiety) due to limited item content in these scales’ full item bank. Marginal reliabilities were credible (0.83 to 0.90). CAT simulations revealed that administering the CAT would save the respondent about 14 minutes compared to administering the full item bank. Conclusions Final scales of the PS-LIBRE1-5 Profile contain 111 items and is a comprehensive measure that captures physical, communication and language, psychological, and social functioning of preschool burn survivors in the community. Applicability of Research to Practice This work lays the groundwork for developing a set of age-based CATs, adding to prior adult LIBRE project. The CAT aims to detect the progress of a child during burn recovery for use in clinical practice.

530 Utilization of Advanced Practice Provider for Quality Virtual Burn Care

Abstract Introduction From the plains of North Dakota to the lakes of Minnesota and beyond, for our patient population, telemedicine has grown to be an important burn care delivery method. Specialized burn care is essential to ensure successful patient outcomes from burn injury. Our institution utilizes an advanced practice provider (APP) either physician assistant or nurse practitioner to lead the telemedicine care instead of the burn surgeon. Given most of the burn care is non-operative management, an APP can deliver burn expertise and high-quality care to the burn patient. Methods A retrospective chart review performed via data extraction from the electronic medical record at a single ABA-verified Burn Center. Dates of review ranged from January 1, 2022, through June 30, 2022. Patient population was Regions Hospital Outpatient Burn Clinic and Telemedicine Clinic volumes. Data review included patient location, mode of visit (in-person or virtual), and time to >95% healed. Inclusion was acute burns of all ages and mechanisms of injury. Exclusion was non-burn wounds, scar management and frostbite patients. Results A total of 1300 (87%) of all outpatient visits performed by APPs with 328 (25%) of these visits conducted via telemedicine. Varying by month, 7-13% of patients were treated exclusively via telemedicine not requiring any in-person burn care. When comparing the patient distance from the burn center (1-50 miles and >50 miles) and time to >95% healed, there was no correlation. Patients who were treated exclusively via telemedicine, lived an average of 205 (5-580) miles from the burn center, had an average TBSA of 2.2 (0.25-55) % and had an average of 18.3 (7-62) days until 95% healed. Compared to patients treated in-person only or combination of in-person and telemedicine, lived an average of 91 (1-631) miles, had an average TBSA of 2.5 (0.25-67) % and had an average of 24.6 (5-80) days until 95% healed. Conclusions A burn telemedicine program led by APPs can facilitate remote expert burn care, all while maintaining standard of care. Limitations were a narrow review window, single center retrospective analysis, and the exact date for time to 95% healed is difficult to determine due to interval follow up windows. Our goal is to further review and analyze our telemedicine and clinic data to optimize burn care delivery with the utilization of APPs, investigate quality of care indicators within telemedicine and reduce transfers and travel for specialized burn care. Applicability of Research to Practice APP led telemedicine improves surgeon availability to do hands on treatment in the Burn Center and allows for outreach and specialized expertise to be delivered across remote distances. It allows for the ability to triage patients and optimize burn clinic resources. Telemedicine can be performed in any location and reduce travel. Telemedicine is reimbursable. Barriers include wound care supply access, technological limitations, state licensing and institutional credentialing.

703 Extubation Success in Pediatric Burn Patients: A 10-Year Review

Abstract Introduction Pediatric burn care presents two unique population subsets that require distinctive care from adult and non-burn patients, respectively. While prior research has led to the creation of best practices for burned adults and non-burn pediatric patients, the standard of care regarding long-term pediatric burn intubation varies widely and deviates from accepted standards in the non-burn pediatric world. In this retrospective review, we analyze one burn center’s experience managing ventilation and extubation of pediatric patients. Methods We reviewed all pediatric patients admitted to the burn and wound care ICU who were intubated for more than 24 hours. Patient data was collected from 2012 through 2022. 442 patients were initially identified and 142 remained after removing screen failures. We analyzed 3 groups which included total burn surface area (TBSA), inhalation injury, and time on the ventilator. Results The first group broken down by TBSA yielded the most significant results in our 7 of 10 metrics. All significant metrics including mortality, length of stay (LOS), and pulmonary hypertension (HTN) were directly correlated to burn TBSA. Patients with higher TBSA were also significantly more likely to require reintubation after coming off the ventilator. Inhalation injury presented on admission was also a significant indicator for developing acute respiratory distress syndrome (ARDS). Patients who remained on the ventilator for >7 days were significantly more likely to develop pulmonary HTN, however mortality and reintubation rates notably did not increase in this group. Conclusions There is much debate in the burn world as to whether standard practices should carry over from other specialties when treating severely burned patients. Much of our data confirms, in pediatric patients, findings of adult patients found in the literature. Mortality, LOS, and time on the ventilator expectedly increased with burn TBSA. Inhalation injury was a significant indicator for ARDS which implies that proper screening for this type of injury is a key to predicting long-term treatment. What is perhaps most notable in this data is the fact that, unlike in the adult burn population, there was no significant difference in mortality between short and long-term intubations. Additionally, patients who required reintubation (n=7) were significantly more likely to have a TBSA >40%, but those who remained on the ventilator >7 days were not more likely to require intubation after extubation. This implies that patients should be left on the ventilator, if necessary, without resorting to aggressive challenge breathing trials for early extubation as is common in adult population. With this data we will also identify our rare cases of pediatric tracheostomy placement and indications for its use. Applicability of Research to Practice This projects shows how intubation of pediatric burn patients can be maintained safely and effectively in the critical care setting.

In Situ Flame-Synthesized Carbon Nanotubes on Carbon Paper as a Microporous Layer for Proton Exchange Membrane Fuel Cells

Microporous layer (MPL) is an important component of the gas diffusion layer (GDL), which can improve the mass transfer rate to enhance the performance of the proton exchange membrane fuel cell (PEMFC). Although the carbon nanotube (CNT) is a promising material for MPL, the preparation and usage of CNT in MPL have many problems, such as macropore blocking, complex and time-consuming preparation, and expensive equipment. In this paper, a simple and cost-effective flame synthesis method to prepare CNT as MPL for PEMFC is proposed. It only takes 30 s to form a three-dimensional porous structure by growing CNT on carbon paper, which changes the pore size distribution of the gas diffusion layer (GDL) and is beneficial for enhancing the mass transfer rate. The density of CNT grown inside the carbon paper is hierarchical. The catalyst of the CNT and the burning time significantly influenced the density of CNT and the properties of the GDL. The maximum power density reached 1184 mW cm–2 for the GDL prepared by this flame method, which indicates an increase by 24.2% compared to the commercial GDL. Furthermore, the analysis by electrochemical impedance spectroscopy (EIS) indicated that the mass transfer resistance of the GDL prepared by the flame method was smaller than that of the commercial GDL. These findings provide a promising approach for the preparation of MPL with CNT.

High-yield spray drying assembly and reactive properties of nanoenergetic mesoparticle composites

Electrospray has been demonstrated to assemble fuel and oxidizer nanoparticles with a gas-generating binder into microscale particle composites. This approach results in reactivity enhancement of nanothermite systems by alleviating reactive sintering of the nanoparticle components due to rapid gasification. However, this method is not readily scalable and amenable to large-scale manufacturing due to its slow solution processing rates and the risks associated with the presence of high electric fields in the presence of electrostatic discharge-sensitive reactive materials. Here, we explore spray drying as an alternative approach to assemble Al/CuO nanoparticles into nitrocellulose (NC)-based mesoparticle composites and evaluate their energetic performance against physically mixed powders and electrosprayed mesoparticles. The spray dried mesoparticles show ∼2–7-fold higher pressurization rates and shorter burn times than their physically mixed counterparts and follow a similar trend with electrospray. The higher reactivity of the mesoparticles is attributed to rapid gas generation and reduced sintering from the decomposition of the NC binder. We further demonstrate that spray drying generates mesoparticles with size (∼1.5–4 μm), morphology, and reactivity enhancement similar to that from the electrospray method, while achieving remarkably high production rates (as high as ∼275 g h−1). Thus, this work presents spray drying as a highly scalable strategy to achieve reactivity enhancement and processability, thereby enabling high-yield manufacturing of energetic materials, which is a prelude to what might evolve into 3-D printing approaches for propellants.

Utilization of the Nannochloropsis microalgae biochar prepared via microwave assisted pyrolysis on the mixed biomass fuel pellets

Nannochloropsis microalgae biochar has become increasingly attractive due to its potential as a component of microalgae-based biodiesel blends. This biochar is a by-product of the pyrolysis process, but its use in the energy sector has been limited. In this study, pellets were formed using microalgae residues and their physiochemical properties were analyzed to assess the feasibility of using microalgae biochar as a fuel source. Three types of biomasses, namely date seed dust, coconut shell waste, and microalgae biochar, were utilized to produce fuel pellets. These pellets were categorized into three types, B1, B2, and B3, based on the composition of the biomass. The inclusion of microalgae biochar in the pellets resulted in enhanced calorific value, as well as improved heating value and bulk density. Moreover, the mechanical strength of microalgae-based pellets was higher due to their high lignin content compared to another biomass. The moisture absorption test results showed that the use of mixed biomass reduced the moisture content over an extended period. Microalgae pellets exhibited higher young's modulus and greater impact resistance, indicating greater mechanical strength. Furthermore, due to their higher calorific value, the combustion time of microalgae pellets was greater than that of other biomass. In conclusion, the results of this study suggest that microalgae biochar can be a promising alternative fuel source for the energy sector.

Hydrothermal carbonization of olive oil industry waste into solid fuel: Fuel characteristics and combustion performance

A low-cost treatment of wet wastes generated by olive oil industry still remains a challenge for the industrial scale applications. In the concept of waste-to-energy, the hydrothermal carbonization (HTC) is suggested as a low-cost valorization way for the wet wastes. In this study, the HTC process was used to obtain clean solid fuel from the wet waste of the two-phase olive mill system. Variation of the fuel properties and combustion performance of obtained solid fuel, hydrochar, with process conditions (temperature and duration) was investigated by carrying out proximate analysis, elemental analysis and thermal analysis. The lignite-like hydrochars having calorific value of 28.4–33.9 MJ/kg were obtained at the temperatures higher than 200 °C. The combustibility index (S) revealed that all obtained hydrochars were suitable solid fuels having reasonable combustion performance and short combustion time. Alkali index values of hydrochars predicted that their combustion in a boiler would be safe. The calculated net energy generation of process was found as 10.2–14.1 MJ/kg dry biomass.

Using polyvinylidene fluoride to improve ignition and combustion of micron-sized boron powder by fluorination reaction

Boron has a promising application in the field of propellants due to its high calorific value. However, the difficulty of ignition and the poor combustion efficiency of boron (B) have severely limited its efficient application. In response to this issue, this paper proposes to improve the ignition and combustion performance of micron-sized boron by the Polyvinylidene Fluoride (PVDF) coating. The effect of PVDF content on the B combustion performance was systematically studied using a Thermogravimetry-Differential Scanning Calorimetry (TG-DSC), a Transmission Electron Microscope (TEM), an X-Ray Diffractometer (XRD), a laser Particle Size Analyzer (PSA), and a high-speed camera. The results show that PVDF can significantly reduce the initial oxidation temperature of B powder and increase its reaction heat. When the PVDF content is 23wt%, the reaction heat and the combustion intensity of B powder reach the maximum and are significantly higher than those of the uncoated B powder. Moreover, the fluorination reaction that occurs during the combustion process not only can effectively shorten the combustion time of B powder, but also has a positive effect on its flame intensity and propagation speed, and it significantly reduces B particle agglomeration, which improves the combustion efficiency significantly. This study lays the foundation for the application of PVDF modified B in B-based solid propellants.

Numerical study on the influence mechanism of different types of burst disc on high pressure hydrogen spontaneous combustion in tube

High-pressure transportation and storage are the current main methods for storing hydrogen. Burst discs, which are common in high-pressure storage devices, can cause hydrogen leaks to ignite and create serious accidents when certain conditions are met. To investigate this, this paper studies the effect of different blasting slot shapes on the spontaneous combustion of leaked high-pressure hydrogen. Numerical simulations, using LES, EDC model, Ten-Step Burst Disc Opening Method and 19-Step Detailed Hydrogen Combustion Mechanism, were conducted to analyze the spontaneous combustion of hydrogen with annular grooves, star grooves, cross grooves and grooveless burst discs. The results of the study show that the shape of the groove in the bursting disc will significantly affect the shock wave structure and spontaneous combustion time of leaked high pressure hydrogen in the tube. Among the four types of bursting discs, the order of spontaneous combustion in the tube is annular groove (approximately 90 μs), star groove (approximately 110 μs), cross groove (approximately 120 μs), and grooveless bursting disc (approximately 130 μs). Secondly, the double spherical shock waves produced by annular groove bursting disc collide with each other, resulting in a higher rising speed of pressure and temperature in the tube than with other bursting discs. Finally, the spontaneous combustion time of the leaked hydrogen is proportional to the open area of the bursting disc. When the opening area is the same, the smaller the exit shape coefficient is, the shorter the spontaneous combustion time is. The research results can provide some reference for the design and application of bursting disc in high pressure hydrogen storage equipment.

Automated power-following control for nuclear thermal propulsion startup and shutdown using MOOSE-based applications

This paper describes an investigation of various automated control strategies applied to a full-core multiphysics Griffin/Bison/RELAP-7 model of a prototypical nuclear thermal propulsion system. In all cases, control is achieved by actuating control drums based on the demanded power and predicted quantities from the numerical model. One key finding is that hybrid proportional integral derivative controllers – a novel type of controller that uses both power and reactivity predicted signals – can demonstrate a level of performance rivaling that of period-generated control. The former requires parameter tuning, while the latter mostly necessitates providing reactivity coefficients and temperature rates of change, which could be very challenging to accurately measure in real-time.In addition, decay heat plays an important role in determining cooling requirements during cooldown phases. A decay heat model, accounting for burn time and throttling, was derived, and is incorporated within the model to simulate the steady-state and shutdown phases and satisfyingly follow the power demand. However, temperature overshoots and non-constant specific impulse during throttling will necessitate further improvements.

Numerical study on the effect of pressure on transient micro-combustion and heat release characteristics of AP/HTPB/Al composite propellant fuel

The effect of pressure on transient micro-combustion and heat release characteristics of AP/HTPB/Al composite propellant is investigated in the present study. Detailed combustion mechanism with 42 species and 136 reactions and segmented regression rate model are established and validated for the propellant fuel. The results show that temporal evolution of regression rate is not synchronous with temperature due to the heterogeneous properties of the burning surface. With combustion time increasing from t = 0.6 ms to t = 6.0 ms, the standard deviation of temperature of the burning surface increases by 65.08% while the standard deviation of regression rate decreases by 18.80%. Although raising pressure increases both the temperature and regression rate of the burning surface, the distribution uniformity of temperature and regression rate exhibits distinct response characteristics to pressure. With pressure increasing from 2 MPa to 10 MPa, the standard deviation of temperature of burning surface decreases by as much as 36.50% due to enhanced heat transfer to the burning surface. However, the standard deviation of regression rate increases by as much as 66.68% with pressure. Both the gas-phase temperature and solid-phase temperature increase and become more uniform with pressure. With progress of combustion, total heat transfer coefficient decreases slightly due to the reduced combustion heat release rate. Although the contribution of heat radiation increases significantly during the combustion process, heat convection is dominant heat transfer. With the increase of pressure, the combustion heat release rate increases significantly due to the enhanced oxidation reactions in diffusion flame. With consumption of the propellant, the combustion heat release rate decreases and squeezes to a smaller region. The experimental results of extinguished burnt surface show that AP particles become higher than the surface of HTPB binder as pressure increases. The non-uniformity of morphology of the burning surface of the AP/HTPB/Al composite propellant increases with pressure.

Experimental study of dynamic combustion behavior and heat transfer of heptane pool fire with burning time under thin fuel thickness (2.0 mm–14.0 mm)

A dynamic combustion period occurs after the liquid fuel ignition, but the combustion mechanism is complicated and unclear due to dynamic heat transfer between the fuel and the substrate. This work uses a method of experimental research and theoretical analysis to study the dynamic combustion behaviour and heat transfer of pool fire with burning time (t) under thin fuel thickness (δ). Research contents include the relation of flame height (Z), burning rate (m˙), heat transfer between fuel and substrate with t, and the evolution mechanism of the output composition of total heat feedback with δ. The research found Z and m˙ increase with t until maintaining constant, whereas δ is different. Heat convection loss increases rapidly, then increases slowly, and finally keeps constant because thin-layer fuel is quickly heated. Heat radiation loss firstly surges, then fluctuates due to the combined effect of the flame shape and necking effect. Total heat loss tends from radiation to convection. The heat for heating fuel and the heat radiation reflected from the substrate are considered in the dynamic combustion stage. The fractions of heating fuel, vaporization heat, heat loss and heat reflection were calculated and studied. This work adds theoretical knowledge of fire dynamics

Flame‐retardant, flexible, and breathable smart humidity sensing fabrics based on hydrogels for respiratory monitoring and non‐contact sensing

AbstractSmart sensing fabrics are becoming increasingly attractive in the emerging wearable areas of medical and military so far. Here, for the first time, we present a smart humidity sensing fabric (SHSF) based on a moisture‐sensitive polyacrylamide hydrogel for respiratory monitoring and non‐contact sensing. Fabricated by in situ cross‐linking of the hydrogel precursors on the fibers of the fabric, the flexible SHSF shows excellent sensitivity, outstanding flame retardance, air permeability, water retention capacity, and stability after treatment with lithium bromide solution. Specifically, its conductance increases more than 311 times as humidity increased from 11% to 98%. Besides, the humidity sensor features good repeatability and the ability to work normally under folding due to its flexible nature. As a clothing material, hydrogel–fabric composite exhibits 4.3 times the burning time compared to cotton fabric, illustrating better flame retardance. The SHSF is used to monitor human breathing and non‐contact finger approaching in real time, demonstrating its flexibility in practical applications. This work provides strategies for preparing high‐performance, flame‐retardant SHSF for emerging wearable electronic devices.

Thermogravimetric assessment for combustion characteristic of torrefied pellet biomass from agricultural solid waste

This present paper is focused on the investigation of combustion characteristics of torrefied pellet biomass from agricultural waste. Four biomass pellet samples such as sugarcane bagasse, Napier grass, Palm Empty Fruit Bunches, and Cassava stem were torrefied in a designed cylinder tubular pyrolysis reactor. The reactor was set up under 30 min of residence time, and the temperature reaction was varied at 200, 250, and 300 °C in an inert atmosphere. The torrefied products were then characterized in terms of their psychochemical properties such as proximate, ultimate, calorific value, and combustion properties. The combustion properties of raw and torrefied biomass pellets during the combustion process were investigated by the thermogravimetric analyzer Exstar SII TG/DTA7300. The samples were heated at an ambient temperature up to 800 °C at a constant heating rate of airflow at 10 °C/min in airflow. The results showed that the moisture content and volatile matter of torrefied pellets decreased by 2 to 5% and 8 to 14%, subsequently. Otherwise, the fixed carbon content is up to three times higher than the raw material. The study conclusively that torrefaction can also able to enhance combustion performance in terms of ignition and burnout temperature, ignition and burnout index, and combustion rate. The results shows that, the ignition and burnout temperatures of torrefied pellets are higher than raw material. The ignition and combustion index of torrefied pellets are lower than raw material, and the torrefied pellets have a longer burning time and a higher combustion temperature.

Preparation, quasi-static, and dynamic compressive mechanical properties of BMG-W energetic structural materials

In this paper, the Zr41.2Ti13.8Cu12.5Ni10Be22.5 amorphous alloy powder and the spherical W particles were used to prepare the BMG-xW (BMG=Bulk Metallic Glass, x = 10, 20, 30, 40, 50 vol%) energetic structural materials (ESMs) by spark plasma sintering. The research results on energy performance indicated that the Zr41.2Ti13.8Cu12.5Ni10Be22.5 alloy powder had excellent thermal reactivity, high combustion enthalpy and combustion integrity. The microstructure, quasi-static, and dynamic compressive mechanical properties of the BMG-xW ESMs were investigated. The quasi-static compression test showed that when the sintering temperature was 365 °C and above, the BMG-xW ESMs with the W content of 20 vol% to 50 vol% had similar fracture strengths and higher plastic deformation abilities than the BMG samples prepared under the same conditions. We have analyzed the plasticity enhancement mechanism of the BMG-xW ESMs. In addition, the failure modes of the BMG-xW ESMs were all shear fracture, which was conducive to exerting their shear self-sharpening. The Hopkinson compression bar test showed that the fracture strength and failure strain of the BMG-xW ESMs were greater than the Zr41.2Ti13.8Cu12.5Ni10Be22.5 BMG under dynamic compression at the same strain rate, and the higher the W content, the fracture strength and failure strain tended to increase. All samples showed obvious flame during dynamic compression. The larger the strain rate, the lower the W content, the shorter the ignition delay time, the faster the flame spreading speed and the longer the combustion time. The damage experiment confirmed that the BMG-xW ESMs had significantly superior damage performance than the Zr41.2Ti13.8Cu12.5Ni10Be22.5 BMG.

An all-natural fire-resistant bioinspired cellulose-based structural material by external force-induced assembly

Natural wood is a widely used structural building material because of its light weight and high strength, yet it is limited by the ignitability. Traditional top-down strategies can delay the burning time of wood-derived materials but hardly reach incombustible performance. Here, we develop a bottom-up external force-induced assembly strategy to fabricate nonburning nacre-mimetic structural materials based on the shear-thinning behavior of cellulose nanofibers, the main component of wood. The highly ordered brick-and-mortar structure endows the structural material with excellent comprehensive mechanical properties and oxygen insulation, giving it better specific flexural strength [143 MPa/(Mg m−3)] and limit oxygen index (100%) than various natural woods. Furthermore, the house model, made of bioinspired structural materials, does not burn or collapse even in a butane blowtorch flame (more than 1100 °C), demonstrating its great potential as a sustainable, lightweight, strong, and safe structural building material.

A Study on Combustion Characteristics of Insensitive Triple-Base Propellant

Research on combustion characteristics can provide basic information and theoretical support for the design of insensitive propellant. This work aims to investigate the combustion characteristics of insensitive triple-base propellant. All propellants were prepared based on same triple-base propellant, but they were desensitized with the same desensitizer in different ways. The high-speed camera, spontaneous luminescence, NO, NH chemiluminescence, and OH-planar laser induction fluorescence (PLIF) methods were employed to capture the combustion flame and derive the distributions of important intermediates. Results show that ignition delay times of insensitive propellants are obviously longer. This indicated that the application of the desensitizer has a partly hindering effect on the early ignition stage. The combustion time of insensitive propellants is mostly similar, which means that the desensitizer has little influence on the intensity of actual combustion. The change in flame height and area of insensitive propellants over time indicated that the combustion progressivity of some insensitive propellants was more prominent, which means that the desensitizer concentration and desensitizing methods all affect the performance of insensitive propellant. The signal intensities of NO and NH show a negative correlation, indicating that a competitive relationship probably exists between the formation of NO and NH radicals during the reaction process. The high concentration of OH mainly locates outside NO, suggesting that there may be a transformation between NO and OH. The maximum signal intensity of NO and NH of different insensitive propellants confirmed that both the concentration of desensitizers and the desensitizing methods exhibit important effect on the reaction process.

Enhancing the combustion and propulsion performance of Al/CuO via introducing AlH3 as fuel substitute

The research on nanothermites mainly focuses on formulation and structural modification, performance optimization and application research. Whereas, the few gaseous products of nanothermites limit the practical applications, especially in microthrusters. Here, various contents of AlH3 was introduced in typical nanothermites (Al/CuO) to replace Al as fuel. The characteristics of Al/AlH3/CuO were examined by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The ignition and combustion performance such as burning rate, unconstrained combustion, ignition temperature and delay time, pressurization and propulsion properties was investigated. Results revealed that when AlH3 content was 20%, Al/AlH3/CuO had the fastest burning rate (189 m/s), the lowest ignition temperature (441.4 °C), the shortest ignition delay time (5.32 ms), the maximum Pmax (1141.3 kPa), the highest pressurization rate (75.06 kPa/μs) and the maximum microthrust (1.61 N). In short, replacing Al with AlH3 in the Al/CuO provides an innovation for creating nanothermites with completely new metal fuels, and also enhances the combustion and propulsion performance.

Fire Resistance Test of Geopolymer Coatings on Non-Metallic Underlying Substrates

This article summarizes the results from the fire resistance test of geopolymer suspensions in the form of coatings on non-metallic substrates. Their heat resistance was evaluated based on the burn-through time compared to the uncoated substrate. Non-metallic substrate materials, extruded polystyrene (XPS) and chipboard (DTD) were chosen as the underlying substrates for GP suspension research. Parameters from the fire resistance test as fire test duration of geopolymer coatings and percentage increase in burn time of geopolymer coatings on an XPS and DTD substrates compared to an uncoated substrate were evaluated. One of the discussed point was also the addition of CaCO3 and Al(OH)3 for studding flame retardancy effect.