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Slim-floor-type of steel-timber hybrid floor systems which use steel beams contained within the depth of the cross-laminated timber (CLT) floor slab offer many benefits, but there is still very little research available on the fire resistance performance of these systems. In the study presented in this paper two furnace tests and numerical simulations have been conducted to investigate the thermal profiles of the steel member and CLT slabs and to obtain information on the temperature development and charring of the hybrid beam section when it is exposed to standard fire conditions. Also, the effects of intumescent fire protection on temperatures and charring performance were investigated. Numerical 2D thermal simulations for unprotected and protected cases were conducted using SAFIR software, and the agreement between experiments and numerical-analysis predictions were in general very good. The results show that intumescent protection reduces the temperatures of the steel and CLT components as well as charring depth significantly, and the start of charring at CLT slab support may be delayed if intumescent paint protection thicker than that required for the load bearing steel member is used. The result also showed that CLT temperatures exceed 100°C already in the early stages of the fire which decrease the strength and stiffness properties of CLT much before the start of charring. Therefore, the fire design of the CLT slab support should not only consider the char depth and residual cross-section analysis but also the reduction in strength. [ABSTRACT FROM AUTHOR]

After the period of halogenated compounds, the period of nano-structured systems, and that of phosphorus (and nitrogen)-based additives (still in progress), following the increasingly demanding circular economy concept, about ten years ago the textile flame retardant world started experiencing the design and exploitation of bio-sourced products. Indeed, since the demonstration of the potential of such bio(macro)molecules as whey proteins, milk proteins (i.e., caseins), and nucleic acids as effective flame retardants, both natural and synthetic fibers and fabrics can take advantage of the availability of several low-environmental impact/“green” compounds, often recovered from wastes or by-products, which contain all the elements that typically compose standard flame-retardant recipes. The so-treated textiles often exhibit flame-retardant features that are similar to those provided by conventional fireproof treatments. Further, the possibility of using the same deposition techniques already available in the textile industry makes these products very appealing, considering that the application methods usually do not require hazardous or toxic chemicals. This review aims to present an overview of the development of bio-sourced flame retardants, focusing attention on the latest research outcomes, and finally discussing some current challenging issues related to their efficient application, paving the way toward further future implementations. [ABSTRACT FROM AUTHOR]

The design of environment‐friendly fireproof rigid polyurethane foams (RPUFs) that completely prevent ignition or the spread of fires is important for energy conservation and emission reductions. In this paper, an intumescent flame‐retardant coating was prepared and coated onto the surface of a RPUF to improve its flame retardancy. Vertical combustion experiments (UL‐94) showed that, compared with the pure RPUF, a RPUF coated with the expansion coating successfully self‐extinguished without a droplet formed after ignitor removal. Thermogravimetric analyses showed that the expanded coating effectively increased the rate of carbon residue formation. Cone calorimetry showed that when the pigment‐to‐binder ratio was 3.5:1, with 5% modified montmorillonite, 6% aluminum hydroxide, and 4% titanium dioxide, the intumescent coating effectively reduced the heat release rate and total heat release of the RPUF. Remarkably, the smoke release rate and total exhaust gas volume showed that the expanded coating provided obviously enhanced smoke suppression. Therefore, the flame retardancy and toxic smoke suppression provided by the RPUF thermal insulation material is essential and very useful for healthy development of human society and the environment. [ABSTRACT FROM AUTHOR]

During a fire, the load‐carrying cross section of timber members will reduce due to charring. This article summarizes experimental investigations into the charring rate of different timber species under standard fire conditions, identifies material properties that contribute to the variations of char rates across the different species, and evaluates the applicability of prescribed charring rates to solid timber, cross‐laminated timber (CLT), and glulam exposed to standard fires. Data from the literature showed that density had the greatest impact on charring rate. The charring rate of timber decreased with increasing density, particularly timber densities >700 kg/m3. Prescribed charring rates from current design standards provide reasonable estimates of the average charring rate of timber with densities <700 kg/m3 exposed to standard fire curves. A linear charring rate of 0.65 mm/min was found to be suitable for CLT and glulam exposed to a standard fire for up to 180 min if the CLT did not experience char fall‐off. The National Design Specification nonlinear charring model may underestimate the char depth of glulam exposed to standard fire curves for longer than 60 min; however, the percent underestimation was small and limited data was available. The review demonstrated the need for data on the char depths of glulam and CLT exposed to standard fire curves for longer than 60 min and particularly for longer than 120 min. [ABSTRACT FROM AUTHOR]

Moso bamboo (MB), carbonized moso bamboo (CMB), natural color bamboo scrimber (NBS), and dark color bamboo scrimber (DBS) were subjected to Poria vaporaria (PP), Gloeophyllum trabeum (GT), Coriolus versicolor (CV) and Trametes versicolor (TV) in laboratory experiments. The differences in surface chromaticity and mass loss of four samples before and after decay were compared. The results showed that the decay resistance of DBS after four wood rot fungal infections reached grade I, and DBS had the best decay resistance among the four samples. MB had the worst decay resistance among the four samples. After being infected by four kinds of wood rot fungi, the color of MB and NBS changed significantly, as the brightness decreased significantly. The red-green axis color index and yellow–blue axis color index of MB and NBS infected by PP, GT, CV, and TV showed significant increases compared to those of untreated samples. The chroma values of MB and NBS increased significantly after the decay test. SEM analysis showed that after the brown-rot test, the hyphae of GT entered the MB vessels and the parenchyma cells through the pits in the vessel, causing the cell structure to be destroyed. [ABSTRACT FROM AUTHOR]

Physical and mechanical properties were evaluated for all-sided charred Pinus taeda and Eucalyptus bosistoana wood by hot plate contact heating system followed by treatment with linseed oil. The water absorption, volumetric swelling, wettability, hardness, modulus of rupture, and modulus of elasticity in bending strength and compression strength parallel to grain were determined. The water absorption and volumetric swell were determined after immersion in water, as measured at various intervals of water immersion up to 120 h. The results suggested that the contact charring process with the addition of a linseed oil application improved water absorption and volumetric swell properties of charred specimens compared to un-charred controls. Hardness of the charred wood decreased by 38% and 43% in P. taeda and E. bosistoana specimens, respectively, compared with their respective controls. The highest reductions were seen in modulus of elasticity and compression strength values in charred P. taeda specimens, while modulus of rupture (MOR) values decreased more in charred E. bosistoana specimens than in charred P. taeda specimens. These results suggested that charring of P. taeda and E. bosistoana wood does improve the moisture-related characteristics; however, their mechanical behavior and hardness decreased.

To investigate stone ablation characteristics of thulium fiber laser (TFL), BegoStone phantoms were spot-treated in water at various fiber tip-to-stone standoff distances (SDs, 0.5 ~ 2 mm) over a broad range of pulse energy (Ep, 0.2 ~ 2 J), frequency (F, 5 ~ 150 Hz), and power (P, 10 ~ 30 W) settings. In general, the ablation speed (mm3/s) in BegoStone decreased with SD and increased with Ep, reaching a peak around 0.8 ~ 1.0 J. Additional experiments with calcium phosphate (CaP), uric acid (UA), and calcium oxalate monohydrate (COM) stones were conducted under two distinctly different settings: 0.2 J/100 Hz and 0.8 J/12 Hz. The concomitant bubble dynamics, spark generation and pressure transients were analyzed. Higher ablation speeds were consistently produced at 0.8 J/12 Hz than at 0.2 J/100 Hz, with CaP stones most difficult yet COM and UA stones easier to ablate. Charring was mostly observed in CaP stones at 0.2 J/100 Hz, accompanied by strong spark-generation, explosive combustion, and diminished pressure transients, but not at 0.8 J/12 Hz. By treating stones in parallel fiber orientation and leveraging the proximity effect of a ureteroscope, the contribution of bubble collapse to stone ablation was found to be substantial (16% ~ 59%) at 0.8 J/12 Hz, but not at 0.2 J/100 Hz. Overall, TFL ablation efficiency is significantly better at high Ep/low F setting, attributable to increased cavitation damage with less char formation. [ABSTRACT FROM AUTHOR]

Physical and mechanical properties were evaluated for all-sided charred Pinus taeda and Eucalyptus bosistoana wood by hot plate contact heating system followed by treatment with linseed oil. The water absorption, volumetric swelling, wettability, hardness, modulus of rupture, and modulus of elasticity in bending strength and compression strength parallel to grain were determined. The water absorption and volumetric swell were determined after immersion in water, as measured at various intervals of water immersion up to 120 h. The results suggested that the contact charring process with the addition of a linseed oil application improved water absorption and volumetric swell properties of charred specimens compared to un-charred controls. Hardness of the charred wood decreased by 38% and 43% in P. taeda and E. bosistoana specimens, respectively, compared with their respective controls. The highest reductions were seen in modulus of elasticity and compression strength values in charred P. taeda specimens, while modulus of rupture (MOR) values decreased more in charred E. bosistoana specimens than in charred P. taeda specimens. These results suggested that charring of P. taeda and E. bosistoana wood does improve the moisture-related characteristics; however, their mechanical behavior and hardness decreased. [ABSTRACT FROM AUTHOR]

The goal of this work is to develop a material model for Norway spruce and Scots pine woods for use in performance-based fire safety design to predict char front progress and heat release in burning timber. For both woods a set of two different models is estimated: one that assumes wood as a single component and another that considers the pyrolysis of wood principal components independently (single and parallel reactions models, respectively). The material models are calibrated using cone calorimeter experiments. The models are intended for a number of different fire scenarios, such as fully developed fire with only little oxygen in the compartment, or the decay period after flaming with exposed char still smoldering. For both spruce and pine, the single and parallel reactions models are able to predict the experiments in the scale of cone calorimeter with near-equal accuracy. Hence, the single reaction model emerges as the preferable level of complexity when modelling charring and heat release, avoiding the increased uncertainty associated with the additional parameters of the parallel reactions model. When scaling up to the simulations of large scale fire tests, the models can predict the char front progress, but the final temperature profile differs from the experimental. The effects of crack forming in the char layer is one of the likely causes, but its mechanisms are not sufficiently known. Therefore, we suggest a closer study on crack formation in wood under fire as future research. [ABSTRACT FROM AUTHOR]

Abstract Charring of timber structural elements in fire is one of the most fundamental phenomena that affect the fire resistance of these elements. For an accurate and safe design of structural fire resistance, it is important to consider charring of timber in natural fire exposures, since determining charring for standard fire exposure, which is a common practice, is outdated and in some cases unsafe, due to the fact that some natural fires can be much more severe. Currently, the prescriptive approach and simplified design methods fail to give information about charring of timber elements exposed to natural fire and thus, a performance-based design is needed. Therefore, this paper presents an upgrade and extension of a recently developed heat-mass-pyrolysis model named PYCIF. Originally, PYCIF model was developed only for standard fire conditions. In the present paper, several studies and analyses are performed to extend model application to natural fire conditions. Firstly, the sensitivity study is performed, where the impact of model parameters on the charring development is investigated. It is discovered, that the kinetic parameters for the reaction rate of the active cellulose production, namely activation energy E 1 and pre-exponential factor A 1, are the most influential. In the next analyses the model calibration for small-scale cone calorimeter tests and large-scale natural fire tests of cross-laminated timber (CLT) floor system is performed. A robust nature of the model is identified since minor parameter calibration is required for an accurate prediction of the charring depth and temperatures in timber elements exposed to various fire conditions. Furthermore, a strong connection between the heating rate of fire and kinetic parameters is discovered. In cases of faster heating rate, the kinetic parameters govern slower reaction rate of active cellulose.

The present communication presents an overview of generating renewable fuels from pine needles through pyrolysis and briquetting technology. Pine needles are the products of leaf shedding in the forests from pine trees and are considered potential fire hazards. Studies conducted in the last few years show that this biomass can be effectively utilized for the production of bio-oil, biochar and briquettes in an environment-friendly manner. Through pyrolysis, pine needles could be converted to 35% bio-oil with a calorific value of 28.52 MJ kg-1, which can be a base material for other fuels and chemicals. The process also yields 25% biochar, which has a half-life of 600-1000 years and is a suitable material for soil carbon sequestration. The proposed pine needlebased energy centre can produce about 3.8 t briquettes, 1.2 t bio-oil, 1.6 t biochar and 1240 Nm3 pyrolysis gas from 10 t pine needles, with an energy efficiency of 87.2%. Greenhouse gas emissions were found to be considerably lower for charring and pyrolysis routes compared to forest burning. [ABSTRACT FROM AUTHOR]

Charring of timber structural elements in fire is one of the most fundamental phenomena that affect the fire resistance of these elements. For an accurate and safe design of structural fire resistance, it is important to consider charring of timber in natural fire exposures, since determining charring for standard fire exposure, which is a common practice, is outdated and in some cases unsafe, due to the fact that some natural fires can be much more severe. Currently, the prescriptive approach and simplified design methods fail to give information about charring of timber elements exposed to natural fire and thus, a performance-based design is needed. Therefore, this paper presents an upgrade and extension of a recently developed heat-mass-pyrolysis model named PYCIF. Originally, PYCIF model was developed only for standard fire conditions. In the present paper, several studies and analyses are performed to extend model application to natural fire conditions. Firstly, the sensitivity study is performed, where the impact of model parameters on the charring development is investigated. It is discovered, that the kinetic parameters for the reaction rate of the active cellulose production, namely activation energy E1 and pre-exponential factor A1, are the most influential. In the next analyses the model calibration for small-scale cone calorimeter tests and large-scale natural fire tests of cross-laminated timber (CLT) floor system is performed. A robust nature of the model is identified since minor parameter calibration is required for an accurate prediction of the charring depth and temperatures in timber elements exposed to various fire conditions. Furthermore, a strong connection between the heating rate of fire and kinetic parameters is discovered. In cases of faster heating rate, the kinetic parameters govern slower reaction rate of active cellulose. [ABSTRACT FROM AUTHOR]

Flame treatment is an ancient technique for surface protection of wood. Further processing of charred wood elements depends on aesthetic and protective requirements. This study presents some general properties and weathering behaviour of the Norway spruce (Picea abies (L.) Karst.) and the European larch (Larix decidua Mill.), protected by variations of sanding, charring, charring + brushing, and coating treatments. Charring and charring + brushing reduced the original mass of the samples by up to 8% and notably changed their colour (ΔE* ≤ 75). A study of chemical properties showed that charring dehydrated the wood and degraded lignin and hemicelluloses. The surface roughness of the wood after charring and charring + brushing increased by as much as 560%, while coating with waterborne acrylic high build stain had no effect on the roughness of these surfaces. The type of surface treatment of the wood did not affect the uptake of the coating in the wood samples, but the uncoated and coated spruce wood absorbed more water than larch wood. Higher water absorption was observed in the samples treated by charring, and it decreased when the char layer was removed by brushing. The film of a waterborne high build stain reduced water uptake only for surfaces treated by sanding and charring + brushing. Larch wood exhibited higher surface hardness (EHz ≤ 1.70 MPa) than spruce wood (EHz ≤ 0.89 MPa), with the brittle char layer reducing the determined hardness of the tested surfaces. During two years of natural weathering, the char layer was removed from the wood surface, even if the samples were additionally coated. The greatest colour changes during weathering were observed on samples treated by sanding (ΔE* ≤ 60) and sanding + coating (ΔE* ≤ 33), followed by samples treated with charring + brushing (ΔE* ≤ 10) and samples treated with charring (ΔE* ≤ 9). In summary, treating wood by charring in combination with brushing was the best wood protection technique. [ABSTRACT FROM AUTHOR]

Cross-laminated timber has been used in buildings since the 1990s. In the last years, there has been a growing interest in the use of this technology, especially with the adoption of the product in increasingly taller buildings. Considering that the product is manufactured from a combustible material, wood, authorities that regulate the fire safety in buildings and the scientific community have carried out numerous research and fire tests, aiming to elaborate codes which contemplate the use of cross-laminated timber in tall buildings. This paper discusses the main results obtained from the fire resistance test of a cross-laminated timber slab carried out in the horizontal gas furnace (3.0 m × 4.0 m x 1.5 m) from the University of Sao Paulo. A vertical load of 3 kN/m2 was applied over the slab and the specimens were exposed to the standard fire curve for 30 min. In addition to the 30-min test, the research also evaluated the thermal behavior of the samples during the 24 h after the burners were turned off. Throughout the test, the slab maintained the integrity and the thermal insulation, and no falling-off of the charred layer was observed. However, the 24-h test indicated that it is mandatory to consider the loss of stiffness and strength of timber caused by the thermal wave observed during the decay phase.

Introduction: Charring process affects the preservation potential of seeds, resulting in limited perceptions of crop assemblages recovered from archaeological layers. Therefore, the specifics of the charring process deserve further investigation. Colloquially referred to as the "Five Grains" (1), bread wheat (Triticum aestivum), foxtail millet (Setaria italica), broomcorn millet (Panicum miliaceum), rice (Oryza sativa), and soybean (Glycine max) represent a set of four major cultivated cereals and a pulse constituting crucial staple food in Chinese history and the most frequently discovered crops at archaeological sites in China. Methods: This paper aims to understand the changes in size, volume, and weight loss of grains under variable aerobic charring conditions. The size and weight were measured for the untreated specimens and the specimens heated at different temperatures and over different time-periods. Results: We found that temperature and exposure time directly affected the grain size. Specifically, the grains of most species shrank at lower temperatures and expanded rapidly at higher temperatures. Discussion: Among the "Five Grains", soybean was the type least affected by charring, followed by wheat, rice, and millet. Volume and weight can be used as conversion factors to minimize the bias in quantitative representation due to varied charring preservation potential. For rice, wheat and soybean, the variation in volume is smaller. For millet, both volume and weight can be used as the control to understand the consequences of charring for the assemblage. Further experiments and comparisons of ancient samples are needed in future studies to investigate other factors that affect the preservation of charred plant remains. [ABSTRACT FROM AUTHOR]

Crack formation on the charring surface of burning wood is an important factor increasing the burning rate by offering a passage for heat and oxygen, but it remains a poorly understood process. This work considers crack formation on pyrolyzing Norway spruce, Scots pine and birch timbers. Timber specimens of different sizes were tested under various radiative heat fluxes in nitrogen atmosphere. The cracking process was followed with an infrared camera mounted above the specimen. The obtained recordings were used to determine the formation times and lengths of cracks and to estimate the validity of an existing thermomechanical model for crack formation. The results show that the crack formation time has no significant dependence on the specimen geometry. Further, the inverse of the square root of crack formation time follows grows linearly with external heat flux, which is a similar dependence as with time for ignition, according to the thermal model of ignition. The analytical model predictions were of correct order of magnitude, but not consistently accurate at all experimental conditions. This could be accounted for the simplifying assumptions within the analytical model, and therefore creating a more detailed three-dimensional numerical model for crack formation is suggested as future research. [ABSTRACT FROM AUTHOR]

• Preparation of CSPC by one-step activation charring. • Making wave-absorbing materials from agricultural waste coconut shells. • By adjusting the pore structure to optimize impedance matching. • The RL min value of porous carbon can reach −37.23 dB at a thickness of 1.5 mm. Coconut shell was a resourceful and renewable biomass waste in our country, which can obtain a rich pore structure after simple charring treatment. In this paper, coconut shell porous carbon (CSPC) material with good wave-absorbing properties was successfully prepared by activating coconut shell powder with KOH and charring at high temperature. The material had a porous structure, honeycomb, with the charring temperature and the proportion of activator gradually increased, the degree of graphitization gradually increased. When the charring temperature was 600 ℃ and the activator ratio was 0.5:1, the minimum reflection loss (RL min) value was −37.23 dB when the sample thickness was 1.5 mm and the test frequency was 16.72 GHz. The coconut shell porous carbon prepared was a new type of electromagnetic wave-absorbing material made from agricultural waste, which can obtain a better microwave absorption effect after simple processing. [ABSTRACT FROM AUTHOR]

Foxtail and broomcorn millets are the most important crops in northern China since the early Neolithic. However, little evidence is available on how people managed these two crops in the past, especially in prehistory. Previous research on major C3 crops in western Eurasia demonstrated the potential of stable carbon and nitrogen isotope analysis of charred archaeobotanical remains to reveal the management of water and manure, respectively. Here, we evaluate the feasibility of a similar approach to C4 millets. Foxtail and broomcorn millet plants grown in pots in a greenhouse under different manuring and watering regimes were analysed to test the effects of management on stable carbon and nitrogen isotope values of grains. Stable nitrogen isotope values of both millets increased as manuring level increased, ranging from 1.7‰ to 5.8‰ in different conditions; hence, it appears a feasible tool to identify manuring practices, in agreement with results from recent field studies. However, the two millets exhibit opposing trends in stable carbon isotope values as watering level increased. The shift in stable carbon isotope values of millets is also smaller than that observed in wheat grown in the same experimental environment, making it difficult to identify millet water status archaeologically. In addition, we charred millet grains at different temperatures and for varying durations to replicate macro-botanical remains recovered archaeologically, and to evaluate the offsets in carbon and nitrogen isotope values induced by charring. We found that the stable nitrogen isotope values of foxtail millet and broomcorn millet can shift up to 1-2 ‰ when charred, while the stable carbon isotope values change less than 0.3‰. Overall, we demonstrate that stable nitrogen isotope values of charred foxtail and broomcorn millet seeds could provide insight into past field management practices, and both carbon and nitrogen isotope values can together inform palaeodietary reconstruction. [ABSTRACT FROM AUTHOR]

A novel phosphorus-nitrogen-containing flame retardant (DOPT) has been successfully synthesized via the substitution reaction of cyanuric chloride, pentaerythritol phosphate and 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide. The chemical structure of DOPT was confirmed by 1H, 31P and 13C nuclear magnetic resonance, Fourier transform infrared spectroscopy and elemental analysis. Then, flame retardants were added to epoxy resin to prepare epoxy resin composites by pouring method. Thermal properties, flame retardancy, and combustion behavior of epoxy resin composites were evaluated by thermogravimetric analysis, vertical burning, limiting oxygen index and cone calorimeter test. Thermogravimetric analysis test showed that the carbon residue rate of DOPT at 800°C reached 52.53%, which indicated that the introduction of high-efficiency char-forming agent triazine and pentaerythritol phosphate groups could significantly improve its char-forming performance and thermal stability. The epoxy resin composite achieved vertical burning V-0 grade and the limiting oxygen index value reached 35.5% when 7 wt% DOPT was incorporated. Furthermore, the cone calorimeter test results manifested that the addition of DOPT stimulated degradation of the epoxy resin matrix during the combustion process and accelerated the formation of an expanded and dense carbon layer. Additionally, the incombustible gas produced during the decomposition of DOPT had played a flame-retardant effect in the gas phase. Hence, compared with neat epoxy resin, the total heat release and total smoke production of the EP-7 wt% DOPT composite decreased by 14.0% and 25.3%, respectively. Moreover, owing to the excellent compatibility and the strong interface effect between DOPT and epoxy resin, the addition of DOPT also enhanced the mechanical and fire resistance properties of the epoxy resin composite. Therefore, it is proposed that DOPT could be exploited as an economical and high-efficiency flame retardant, and it has considerable prospects in flame retardant epoxy resin composites. [ABSTRACT FROM AUTHOR]

The ignition of four different PVC-based electric cables was studied using cone calorimeter and the influence of the charring phenomenon on ignition was investigated. The thermophysical and optical properties of the sheaths before decomposition were measured. The kinetics of charring was studied by photogrammetry. It was shown that charring occurs for three cables before ignition at heat flux lower than 45 kW/m2. The lower is the heat flux, the higher is the char amount at ignition. In spite of the char formation, it was observed that the time-to-ignition of the cables can be properly calculated using the well-known Quintiere's equation, considering an apparent temperature of ignition. This apparent temperature at ignition was found in the range 312°C to 349°C for the four electric cables. [ABSTRACT FROM AUTHOR]

SUMMARY: Performance‐based design of the timber structures' fire resistance is often based on the reduced cross section and thus relying on empirical and numerical assessment of the charring propagation. The current work aims to construct models for the pyrolysis of spruce and pinewoods to allow coupled simulations of the cross‐section reduction and burning rate in fire models. Kinetic models are formulated based on thermogravimetric data and supported by the heats of pyrolysis and combustion measurements by differential scanning calorimetry and microscale combustion calorimetry, respectively. The results from these small‐scale measurements are consistent with each other, and the heats of pyrolysis and combustion are determined for the wood primary components by fitting the simulations to the experimental results. Heat release models are constructed based on the small‐scale tests, and cone calorimeter experiments are used for the estimation of the physical properties and for the heat release model validation. [ABSTRACT FROM AUTHOR]

Flame treatment is an ancient technique for surface protection of wood. Further processing of charred wood elements depends on aesthetic and protective requirements. This study presents some general properties and weathering behaviour of the Norway spruce (Picea abies (L.) Karst.) and the European larch (Larix decidua Mill.), protected by variations of sanding, charring, charring + brushing, and coating treatments. Charring and charring + brushing reduced the original mass of the samples by up to 8% and notably changed their colour (ΔE* ≤ 75). A study of chemical properties showed that charring dehydrated the wood and degraded lignin and hemicelluloses. The surface roughness of the wood after charring and charring + brushing increased by as much as 560%, while coating with waterborne acrylic high build stain had no effect on the roughness of these surfaces. The type of surface treatment of the wood did not affect the uptake of the coating in the wood samples, but the uncoated and coated spruce wood absorbed more water than larch wood. Higher water absorption was observed in the samples treated by charring, and it decreased when the char layer was removed by brushing. The film of a waterborne high build stain reduced water uptake only for surfaces treated by sanding and charring + brushing. Larch wood exhibited higher surface hardness (EHz ≤ 1.70 MPa) than spruce wood (EHz ≤ 0.89 MPa), with the brittle char layer reducing the determined hardness of the tested surfaces. During two years of natural weathering, the char layer was removed from the wood surface, even if the samples were additionally coated. The greatest colour changes during weathering were observed on samples treated by sanding (ΔE* ≤ 60) and sanding + coating (ΔE* ≤ 33), followed by samples treated with charring + brushing (ΔE* ≤ 10) and samples treated with charring (ΔE* ≤ 9). In summary, treating wood by charring in combination with brushing was the best wood protection technique.

Background: Insular glioma was considered a nonsurgical entity due to resection-associated morbidities. The advancement in neurosurgical techniques and adjuncts used in the last two decades made the resection of insular gliomas simpler for neurosurgeons with the maximum extent of resection and acceptable morbidity rates. The complex anatomy of this region remains a challenge for neurosurgeons and requires expertise. The key factors to achieve complete resection in the insular region are the thorough knowledge of surgical anatomy and meticulous microsurgical techniques. Intraoperative adjuncts such as image guidance along with cortical and subcortical mapping assist in excellent outcomes.Objective: In this study, we describe the operative technique and application of trans-Sylvian approach to do the compartmental dissection done by the senior author, along with challenges faced, with the hope to highlight the efficacy of the approach to achieve maximal resection of this entity without compromising patient's safety.Materials and Methods: A 32-year-old right-handed gentleman presented with episodes of excessive salivation, tingling sensation on the right side of the body along with nausea that lasted for 15-20 s for the last 8 months and one episode of speech arrest without any loss of consciousness and motor or sensory deficit. CEMRI of the brain was suggestive of left insular glioma. The patient underwent left pterional craniotomy, and gross total resection of the tumor was done using compartmental dissection.Results: At follow-up after 1 month, the patient is seizure-free without any speech difficulty and motor or sensory deficit.Conclusion: Compartmental dissection of insular glioma is a safe and efficacious technique to achieve gross total resection of the tumor in this complex region without morbidity. [ABSTRACT FROM AUTHOR]

Summary: The results presented in this paper are part of a multi‐partner collaborative project named 'The Épernon Fire Tests Programme', the purpose of which is to analyse the different behaviours of combustible and non‐combustible loaded structures when they are tested under standard and 'natural' fires. The project has several objectives, such as quantification of the energy participation of combustible materials in fire tests, the influence of combustible surfaces and ventilation factors on the dynamics of compartment fires, and the thermo‐mechanical behaviour of concrete and timber elements under natural fires. This paper focuses on the thermo‐mechanical behaviour of cross‐laminated timber (CLT) slabs under standard and natural fires. The objective is to provide new experimental data on the behaviour of unprotected CLT slabs exposed to fire. In addition, we present a detailed analysis of the thermo‐mechanical behaviour of the slabs, particularly aimed at better understanding the mechanical failures of some of the slabs during and after fire exposure. [ABSTRACT FROM AUTHOR]

Leather is among the most ancient, widely used materials worldwide. Industrial-scale leather production produces large quantities of organic waste attained during shaving and buffing steps during processing. In this study, leather wastes (LW) are used as fillers in flame retarded polymer composites. LW is investigated as a multifunctional bio-filler that enhances the fire performance of flame retarded poly(ethylene–vinyl acetate) (EVA) containing phosphorus flame retardants (P-FRs) ammonium polyphosphate (APP) or a melamine-encapsulated APP (eAPP). Using LW from tanneries as adjuvants to enhance P-FRs in EVA reduces industrial wastes that otherwise require costly waste management solutions. Materials are characterized multi-methodically via mechanical tests, electron microscopy, rheology, thermogravimetric analysis, evolved gas analysis, and condensed phase FTIR, also reaction-to-small-flames and cone calorimeter tests. EVA containing 10 wt-% LW and 20 wt-% P-FRs achieve 20% reductions in fire loads versus EVA, and up to 10% reduction in effective heats of combustion versus EVA with equal (30 wt-%) P-FR loadings. Enhanced char stabilization of EVA composites with LW and P-FRs lowered peaks of heat release rates up to 53% compared to EVA, and up to 40% compared to equal P-FRs loadings. Synergisms between LW and P-FRs in EVA are quantified. A chemical decomposition mechanism is proposed.

One-sided surface charred European beech wood (Fagus sylvatica L.) was studied. Radial and tangential specimens of dimensions of 50 × 25 × 350 mm were one-sided surface charred at 200, 250, 300, 350, and 400 °C for various times using a contact heating system. Specimens of dimensions of 50 × 25 × 50 mm3 were prepared for treatment intensity analysis and its effect on surface wettability. Density profiles of the radial and tangential charred specimens were determined using X-ray densitography with a resolution of 0.05 mm. The wettability of the one-sided surface charred wood specimens was analyzed via contact angle, measured using the sessile drop method and determined over 10 to 150 s. The oven-dried specimens were partially submerged in water and water uptake was recorded after 2, 4, 6, 8, 10, 48, and 72 h according to EN-927-5. The surface density of the radial specimen groups charred at 200 °C for 6 min and 250 °C for 4 min decreased by about 4.5 to 8.2%. With increasingly severe charring, the surface density decreased by about 15.5 to 33.5%. A mild charring process produced a surface charred layer of approx. 2 mm, while higher temperatures and longer times affected the density up to 4–6 mm beneath the surface. Differences were found between the water uptake of the radial and tangential charred beech specimens. The most significant decrease of 56% in water uptake was recorded for the radial group prepared at 200 °C for 20 min after floating in water for 72 h. Water uptake in the radial groups modified at 250 °C for 4 and 6 min after 72 h decreased by 38% and 36%, respectively. The tangential groups did not show any statistically significant decrease. The average water uptake of the groups charred at 200 °C for 20 min, 350 °C for 2 min and 400 °C for 1 min was greater than that of the reference; the variability of the measured data was significantly greater due to the highly anisotropic character of the tangential specimens. Micro cracks were also visible on the surface. Concluding from the results of this study, one-sided surface charred beech wood exhibits increased potential in terms of wood–water related properties when a temperature range of 200–400 °C is applied. [ABSTRACT FROM AUTHOR]

Summary: A series of experiments have been conducted to measure the in‐depth heating of laminated bamboo samples subjected to heat fluxes of 5, 10, 30, and 60 kW/m2, either perpendicular or parallel to the grain. These heat fluxes were chosen to induce different phenomena within the material—from inert heating to moisture evaporation, pyrolysis, oxidation, and flaming—so that the effects of these can be isolated and evaluated separately by simple heat‐transfer models. Moisture migration along the fibres becomes a critical factor when bamboo is heated parallel to the grain, resulting in increased convective heat transfer to deeper parts of the material and an accumulation of moisture in depth that accentuates the endothermic plateau in the temperature profiles around 100°C. Average charring rates for 60 minutes of exposure under 60 kW/m2 were 0.74 and 0.70 mm/min for perpendicular and parallel heating, respectively. The thickness of the heated layer was much larger for parallel heating due to moisture migration, which is less significant perpendicular to the grain. Inert heat diffusion is a good approximation at heat fluxes of 5 and 10 kW/m2, but exothermic oxidation reactions become critical above 400°C and must be included in future models. [ABSTRACT FROM AUTHOR]

Engineered timber is being used to create increasingly taller structures, with building codes adapting to reflect this drive. While these structures continue to become more common, there has been little investigation into the possibility of repairing fire-damaged timber structural members, leaving practitioners with little guidance in the event of a fire and insurance companies with little information to assess risk. The research herein attempted to repair fire-damaged timber members by removing damaged portions of the timber and replacing them with new timber panels secured with structural screws. Members were loaded in four-point bending, and the findings concluded that the members were able to regain a significant amount of stiffness compared to the control members and on average deflected 19% less than they did prior to repair. The repaired members were not able to reach full strength, however, failing at a load ranging from 49% to 66% of the failure load of the control members. This indicates the need to further examine possible alterations that may improve this repair procedure to the point where composite action is fully enabled and a larger portion of the original strength is recovered. A hypothetical cost analysis based on this repair procedure was provided herein, aiming to help direct several research gaps to be addressed in order to enable the repair of fire-damaged timber. [ABSTRACT FROM AUTHOR]

The paper presents a novel approach to determine charring of wood exposed to standard and natural fire that is based on a new numerical model named PyCiF. The new model couples an advanced 2D heat-mass model with a pyrolysis model. A new charring criterion based on a physical phenomenon is implemented in the PyCiF model to determine charring of wood. This presents the main advantage of the new PyCiF model in comparison to common modelling approaches, which require an empirical value of the charring temperature that is often called the char front temperature. The fact that the char front temperature is not an explicit value as assumed by the isotherm 300 °C is advantageously considered in the presented approach where an assumed empirical value of the char front temperature is not directly required to determine the thickness of char layer. The validation of the PyCiF model against experimental results showed great model accuracy, meaning that the model is appropriate for the evaluation of charring depths of timber elements exposed to the standard fire as well as the natural fires. Additionally, as shown in the case study, the presented approach also enables to determine the char front temperature for various natural fire exposures. This will be especially important for the upgrade of the new design methods for fire safety of timber elements exposed to natural fire given in the various design codes such as Eurocode 5. [ABSTRACT FROM AUTHOR]

Engineered timber is an innovative and sustainable construction material, but its uptake has been hindered by concerns about its performance in fire. Current building regulations measure the fire performance of timber using fire resistance tests. In these tests, the charring rate is measured under a series of heat exposures (design fires) and from this the structural performance is deduced. Charring rates are currently only properly understood for the heat exposure of a standard fire, not for other exposures, which restricts the use of performance-based design. This paper studies the charring rates under a range of design fires. We used a multiscale charring model at the microscale (mg-samples), mesoscale (g-samples), and macroscale (kg-samples) for several wood species exposed to different heating regimes and boundary conditions. At the macroscale, the model blindly predicts in-depth temperatures and char depths during standard and parametric fires with an error between 5% and 22%. Comparing simulations of charring under travelling fires, parametric fires, and the standard fire revealed two findings. Firstly, their charring rates significantly differ, with maximum char depths of 42 mm (travelling), 46 mm (parametric), and 59 mm (standard fire), and one (standard fire) to four (travelling fire) charring stages (no charring, slow growth, fast growth, steady-state). Secondly, we observed zero-strength layers (depth between the 200 °C and 300 °C isotherm) of 7 to 12 mm from the exposed surface in travelling fires compared to 5 to 11 mm in parametric fires, and 7 mm in the standard fire. Both traditional design fires and travelling fires, therefore, need to be considered in structural calculations. These results help engineers to move towards performance-based design by allowing the calculation of charring rates for a wide range of design fires. In turn, this will help engineers to build more sustainable and safe structures with timber. [ABSTRACT FROM AUTHOR]

Abstract Coal contains a significant concentration of free radicals as a result of the coalification process. One of the experimental methods sensitive to the presence of radicals is electron spin resonance (ESR), and differences in ESR spectra for different macerals may provide insight into coal-forming processes. In this study, ESR data along with the H/C atomic ratio (to infer the aromatic fraction) are used to characterize coal samples with the aim of assessing a fire-origin for dominant inertinite macerals. A medium rank C bituminous Witbank No. 4 Seam Upper coal (the parent) was density-fractionated to create vitrinite-rich and inertinite-rich samples. The parent sample consists of 42 vol% vitrinite and 49 vol% inertinite. The density-fractionated samples comprise of 81 vol% total vitrinite (dominated by collotelinite and collodetrinite), and 63 vol% total inertinite (dominated by fusinite, semifusinite, and inertodetrinite). The H/C ratio is 0.74 for the inertinite-rich sample, and 0.85 for the vitrinite-rich counterpart, suggesting the former sample is more aromatic. The ESR spectra obtained for the three samples were found to fit best using a Lorentzian distribution. The fit is noticeably better for the aromatic inertinite-rich sample, for which the spectrum is symmetric. This is attributed to pronounced electron mobility and exchange interactions. The higher radical content of the inertinite-rich and parent samples is attributed to the presence of specific inertinite macerals, namely: fusinite, semifusinite, and inertodetrinite. And, owing to the greater radical content of the inertinite-rich sample, the dominant inertinite macerals are interpreted to have formed through charring of plant matter.

The aim of this research was to produce reference data for the study and identification of fibres of carbonised excavated textiles. Thus, the effects of carbonisation (incomplete burning) on the morphology and dimensions of selected fibres used in textile production were investigated. A set of standard test, commercial, and hand-made fabrics, of four cellulosic (cotton, flax, hemp, nettle) and two proteinaceous (silk, wool/ wool felt) fibres, were used for the experiments. Samples were carbonised in a limited oxygen environment at 250, 350, and 500°C for one hour (apart from the wool samples for which the duration of the experiment had to be lowered to six minutes). Wool and silk samples were destroyed at temperatures above 250°C. All cellulosic and the silk samples shrank and their weight was reduced at different percentages that increased as the temperature increased. Exceptionally, wool textile samples exhibited extreme shrinkage but also an increase in their weight. Similarly, the fibre diameters of the cellulosic and silk fibres shrunk gradually at different degrees as the temperature increased, and some exhibited marked degradation patterns, like lacerations in flax, ridges in hemp, raggedness in nettle, and cracks in silk fibres. Wool fibres swell locally but retained the scale pattern on the surface. In general, an increase in the weave count of the textile samples was observed. However, the morphology of the fibres characteristic to their identification did not alter to an unrecognisable degree as a result of artificial carbonisation, as long as the material was preserved. [ABSTRACT FROM AUTHOR]

Wood is a common flammable material in the building fire and the dominant fuel in the wildland fire. In this work, disc wood slices were examined under irradiation to characterize the smoldering burning and the corresponding deformation behaviors. Due to interactions between chemical reactions and thermomechanical stresses, four successive deformation stages were observed and hypothesized: (Ⅰ) drying shrinkage to ∪ shape, (Ⅱ) irradiation-driven thermal expansion to ∩ shape, (Ⅲ) pyrolysis shrinkage to ∪ shape, and (Ⅳ) oxidation-driven thermal expansion to ∩ shape. For these 5–15 mm thick samples, the degree and occurrence of these deformation stages are sensitive to the aspect ratio (i.e. D / δ). Increasing the slice thickness decreases the deformation in the first three stages but increases the deformation of the fourth stage. These experimental observations are qualitatively reproduced by a 2-D finite-element numerical model, coupling 3-step heterogeneous kinetics with a thermomechanical solver. Modeling results further verified the underlying heterogeneous processes (dehydration, pyrolysis, and oxidation) and thermomechanical stresses (thermal expansion and pre-stress) for each deformation stage. This study helps understand the influence of burning processes on the deformation of wood and the failure of timber structures. [ABSTRACT FROM AUTHOR]

Rice cultivation over Asia has several thousand years of history. Adequate water availability is a prime factor for the cultivation of rice in this region. The remains of rice at the archaeological sites, therefore, provide an indirect clue on rainfall in this region. The stable isotopic compositions in remains of rice grains allow estimation of rainfall condition during rice cultivation. Often, such remains found at the archaeological sites suffer from the process of charring, which is likely to modify the original isotopic signature. Here, we performed charring experiments on rice grains at two different temperatures, i.e. 230°C and 250°C and documented the changes in the morphology and carbon isotopic composition (δ13C). A noticeable morphological shift was registered in the samples with progressive duration and temperature of charring. Further, cellulose was extracted and analysed for δ13C. Our results showed that the shift in δ13C observed for charred rice was relatively lower as compared to that observed in other cereals. [ABSTRACT FROM AUTHOR]

A quantitative understanding of the thermal transport within a growing intumescent char layer remains largely unsolved. The development of improved techniques to analyze charring and intumescent materials is necessary to investigate the physics of heat transfer within the char. To aid in this endeavor, a systematic methodology to parameterize comprehensive pyrolysis models for charring and intumescent materials is presented. Thermogravimetric analysis, differential scanning calorimetry and microscale combustion calorimetry were conducted on 4–7 mg samples to analyze the kinetics and thermodynamics of thermal decomposition and determine heats of complete combustion of gaseous pyrolyzates. A multi-step reaction mechanism, consisting of sequential first-order reactions, was constructed to capture the physical transformations and chemical reactions observed in the milligram-scale experiments. 0.07 m diameter disk-shaped samples were gasified in the Controlled Atmosphere Pyrolysis Apparatus II to characterize the thermal transport within the condensed phase material and evolving char layer. ThermaKin2Ds was employed to interpret the experimental data using inverse analysis techniques. Bisphenol A polycarbonate and poly(ether ether ketone), widely used intumescent materials, were analyzed within this study. The resulting two-dimensional models of bisphenol A polycarbonate and poly(ether ether ketone) were capable of predicting the experimental gasification mass loss rates with a mean error of 17.8% and 16.9%, respectively. An analysis of the char pore structure was also conducted from which quantitative relationships were subsequently developed between relevant thermal transport quantities and physical descriptors of the char's physical structure. Two prominent linear correlations were discovered: the char's effective thermal conductivity increased as a function of increasing volume-weighted mean pore diameter and the product of density and thermal conductivity increased with an increasing char porosity based on image analysis. Finally, a brief sensitivity analysis of the polycarbonate and poly(ether ether ketone) burning rates was conducted to determine which key material properties were responsible for the observed differences in flammability. [ABSTRACT FROM AUTHOR]

Pine needles are the waste of pine forest and produced in a substantial amount every year during the fall. If not extracted from forest bed, they cause a widespread forest fire. In this study, pine needles were converted to char at different temperatures using a screw type pyrolyzer with an aim to find out the effect of thermal stress on the properties of chars and their intended end uses. The chars were evaluated for intrinsic physico-chemical transformations in comparison with the raw pine needles. Differences between chars produced in three temperatures and the raw biomass were studied by thermogravimetric analysis. It was found that the char produced at higher temperature showed a superior profile of apparent activation energy as compared with the char from low temperature. Coats–Redfern kinetics was used to compare the activation energies of chars and raw biomass, which showed that the char obtained from higher temperature had better thermal stability. From this study it can be concluded that chars produced at low temperatures in the screw reactor are useful as source of fuel, whereas the char of higher temperature is suitable for soil application and preparation of activated char. [ABSTRACT FROM AUTHOR]