The challenges of this work focus on better understanding combustion characteristics and their importance to fire hazard by performing thermogravimetric analysis (TGA). The ultimate goal is to provide a methodology for determining the most relevant indices for a robust fire hazard classification of the species. One of the principles of this methodology is the use of a linear regression method for determining the indices and the activation energy. To achieve this scope, chemical, thermal and kinetic analysis will be performed. Nine combustion indices were calculated and compared to assess combustion characteristics such as ignition, combustion and burnout. Experiments were carried out at three heating rates of 10, 15 and 20 °C min−1 under air atmosphere. A selection of forest materials frequently devastated by wildfire, i.e., Quercus pubescens (QP), Quercus suber (QS), Olea europaea (OE) and Genista Salzmannii needles (GSN), were studied. The TG-DTG curves have shown that the combustion process consists of two stages: devolatilization and char oxidation. The whole process was controlled by the release of volatile gases. According to the relative linearized (RL) index of spontaneous ignition, the samples were ordered as follows: OE > GSN ≥ QS > QP. OE appears to be the most reactive and prone to spontaneous ignition compared to the other samples. The same order was achieved for the combustion characteristic index and, approximately, for the integrated flammability. On the other hand, the average Ea at the low temperature stage of the combustion process was low for GSN (147 ± 9 kJ mol−1) and OE (159 ± 4 kJ mol−1) and high for QP (179 ± 14 kJ mol−1) and QS (174 ± 3 kJ mol−1). Finally, this work provides valuable insight into the relationship between chemical properties and combustion indices and the components that make some indices more effective than others.

Climate change causes more frequent and destructive wildfires even transforming them into megafire. Moreover, all biomass fires produce emissions of carbon compounds in the form of soot to the atmosphere with a significant impact on the environment and human health. Indeed, the soot is causing the formation of PAHs from (a) the high temperature thermal alteration of natural product precursors in the source organic matter and (b) the recombination of molecular fragments in the smoke. However, these molecules are known to have carcinogenic effects on human health. It is therefore interesting to quantify the 16 PAHs concentration extracted from soot emitted in open diffusion flame of biomass combustion. To achieve this objective, an analytical method developed for the study of kerosene combustion has been adapted for soot from biomass. This new method allowed to quantify the 16 PAHs defined as priority pollutants by the US EPA for their carcinogenic mutagenic effect and on human health.

Investigations were conducted with the aim to improve the energetic characterization of peats with different geological origin, hydrology, and botanical composition. Special attention was paid to the effects and kinetics of thermal treatment of peat decomposition in an oxidative atmosphere. Experiments were carried out using thermogravimetry, differential scanning calorimetry, and a calorimetric bomb. The present study shows that thermal decomposition process consists in a devolatilization step between 473 and 650 K and a combustion step between 650 and 773 K. Thermochemical properties (i.e., degree of decomposition, ultimate analysis, and heating value) were determined for each sample and correlated to thermal behavior. Based on the experimental results, the kinetic parameters for pyrolysis and combustion of boreal peat were estimated using a three-step model. The kinetic triplet of each reaction was estimated using the hybrid kinetic method Cancellieri et al. (Thermochim Acta 438:41–50, 2005). These results will assist in the development of an energetic classification of peat fuels.

The University of Corsica is contributing to the research of both efficiency and integration of renewable energy in the main electrical grid. Since 2013, a scientific program concerning the valorization of biomass energy has been developed to investigate the methane potential through the anaerobic digestion process of lignocellulosic resources. In Corsica, due to the clearing brush policy to prevent forest fires, cellulosic wastes are generated. Besides, Corsica is an important producer of essential oil from Mediterranean species thanks to a process generating an important amount of dried vegetation as waste every year. The aim of this preliminary study on biomass as renewable energy was to characterize and to select the most appropriate substrates for the anaerobic digestion process. Fiber contents and Biochemical Methane Potential (BMP) were performed on five substrates. Heather, rockrose and strawberry tree were chosen as representative of forest fuels. Water distillation residues of laurel and immortelle were considered as natural resource wastes. On this work, we focus on the three species which had the best BMP. Rockrose, dry residue of immortelle and strawberry tree produced 139, 124 and 87 Nm3 CH4 per grams of volatile solids, respectively. The ratio holocellulose: lignin, thanks to the Van Soest method of fiber determination, was determined for those species: 3.8, 3.4 and 1.7. This parameter is a key factor to take into account for the correlation of the BMP with the compositional characteristics. Further work will be performed on these chosen substrates to optimize the anaerobic digestion process in 15 L-reactors.

Wildland fires represent a serious threat to forests and wooded areas of the Mediterranean Basin. As recorded by the European Commission (2009), during the last decade Southern Countries have experienced an annual average of about 50,000 forest fires and about 470,000 burned hectares. The factor that can be directly manipulated in order to minimize fire intensity and reduce other fire impacts, such as three mortality, smoke emission, and soil erosion, is wildland fuel. Fuel characteristics, such as vegetation cover, type, humidity status, and biomass and necromass loading are critical variables in affecting wildland fire occurrence, contributing to the spread, intensity, and severity of fires. Therefore, the availability of accurate fuel data at different spatial and temporal scales is needed for fire management applications, including fire behavior and danger prediction, fire fighting, fire effects simulation, and ecosystem simulation modeling. In this context, the main aims of our work are to describe the vegetation parameters involved in combustion processes and develop fire behavior fuel maps. The overall work plan is based firstly on the identification and description of the different fuel types mainly affected by fire occurrence in Sardinia (Italy) and Corsica (France) Islands, and secondly on the clusterization of the selected fuel types in relation to their potential fire behavior. In the first part of the work, the available time series of fire event perimeters and the land use map data were analyzed with the purpose of identifying the main land use types affected by fires. Thus, field sampling sites were randomly identified on the selected vegetation types and several fuel variables were collected (live and dead fuel load partitioned following Deeming et al. , (1977), depth of fuel layer, plant cover, surface area-to-volume ratio, heat content). In the second part of the work, the potential fire behavior for every experimental site was simulated using BEHAVE fire behavior prediction system (Andrews, 1989) and experimental fuel data. Fire behavior was simulated by setting different weather scenarios representing the most frequent summer meteorological conditions. The simulation outputs (fireline intensity, rate of spread, flame length) were then analyzed for clustering the different fuel types in relation to their potential fire behavior. The results of this analysis can be used to produce fire behavior fuel maps that are important tools in evaluating fire hazard and risk for land management planning, locating and rating fuel treatments, and aiding in environmental assessments and fire danger programs modeling.

In situ Raman scattering studies allow following real-time evolutions of volume or surface structures under extreme conditions. In nuclear materials sciences, ion irradiation-induced atomic organization modification and water radiolysis are of a major interest. In order to better understand these phenomena, we have developed an in situ versatile portable Raman spectroscopy system coupled with a cyclotron accelerator, allowing monitoring of a solid/liquid interface under irradiation and thus giving access to effects of radiolysis. The different parts of the system and their improvements are described in details. The system efficiency is highlighted by a comparative study of the time dependence of UO2 surface modification induced, on one hand by contact with water under irradiation by 5?MeV He2+ particles, and on the other hand by pure chemical alteration, through contact with a hydrogen peroxide solution. Copyright (c) 2012 John Wiley & Sons, Ltd.

Peat is an organic and flammable material used for energy generation and involved in accidental wildfires. Smoldering combustion is governed by heterogeneous chemical reactions of drying and pyrolysis of the bulk solid and oxidation at the surface. In these phenomena, the drying process and its rate is an important mechanism. The aim of this research was to determine thermokinetic constants (TKCs) for the drying process at different scales for boreal peat samples from two regions and three depths. The drying experiments of various kinds of peat were mathematically described by two methods. To calculate the heat of water evaporation, inverse kinectic problems and the Kissinger–Akahira–Sunose method were used. For the determination of kinetic parameters, dynamic for micro scale and isothermal for macro scale experiments were conducted. The experimental data and corresponding TKCs for each peat type do not differ significantly from each other. This suggests that neither the scale nor the peat origin have a s...

Advanced knowledge of the mechanisms and kinetic parameters controlling the thermal decomposition of peat is of importance for understanding smouldering peat fires and quantify fire risk. Smouldering fires do not have the visual impact of the flaming front but constitute an important wildfire phenomenon because of the associated large carbon emissions and damage to a valuable ecosystem. Moreover, in case of extreme dry conditions or strong winds, smouldering fires develop easily into scrub or forest flaming fire. In this context, a thermal study on three different types of peat has been conducted: two high-moor peat types collected in Edinburgh (Scotland) and in Tomsk (Siberia), and one transition peat from Tomsk. The botanical composition, degree of decomposition and ultimate analysis were determined for the different samples and compared. These parameters were correlated to thermal behaviour obtained by Thermogravimetry experiments. Significantly different degradation behaviour is observed for the different peat types. A kinetic method to predict the temperature of the sample at high heating rates is applied. Comparison shows a good correlation between experimental and numerical results. (C) 2011 Elsevier Ltd. All rights reserved.

The analysis of combustion kinetics in the gas-phase is decisive for wild land fire behavior modeling. However, the use of detailed reaction mechanisms, which involves a large number of species and reactions, is impractical due to large computational time requirements. The present work proposes a five-step chemical kinetic mechanism to simulate the gas phase combustion processes taking place in wildland fires. Both experimental data and data from simulations run using the PSR code from the CHEMKIN-II package with a detailed kinetic mechanism (GDF-kin 3.0) have been used to calibrate and evaluate the global model under typical wild land fire conditions in terms of the inlet mixture composition, equivalence ratio, and range of temperatures.

Forest fires are can be fatal for firefighters owing to the phenomenon of eruptive fire. The hypothesis of this study is that biogenic volatile organic compounds (BVOCs) accumulate in the vicinity of the fire front. One of the factors required for an eruptive fire to take place is that BVOC concentrations must be between their lower flammable limit and upper flammable limit. When this accumulation of BVOCs is exacerbated by specific geographical zones (e.g. small valleys, thalwegs, canyons), the combination of these two factors can lead to situations with a very high flammability potential, representing a considerable risk for firefighters. In France, 16 firefighters have been fatally injured over the last 15 years. This work was carried out on three species of the Mediterranean basin: Pinus laricio Poir., Pinus pinaster Ait. and Cistus monspeliensis L. The maximum BVOCs emitted as a function of temperature (50–200°C) by these species were 147.9, 11.6 and 56.0 g m–3 respectively. The quantities of BOVCs emitted by P. laricio and C. monspeliensis were sufficiently high for eruptive fires to occur.

We studied the parameters to optimize the production of negatively-charged nitrogen-vacancy color centers (NV-) in type~1b single crystal diamond using proton irradiation followed by thermal annealing under vacuum. Several samples were treated under different irradiation and annealing conditions and characterized by slow positron beam Doppler-broadening and photoluminescence (PL) spectroscopies. At high proton fluences another complex vacancy defect appears limiting the formation of NV-. Concentrations as high as 2.3 x 10^18 cm^-3 of NV- have been estimated from PL measurements. Furthermore, we inferred the trapping coefficient of positrons by NV-. This study brings insight into the production of a high concentration of NV- in diamond, which is of utmost importance in ultra-sensitive magnetometry and quantum hybrid systems applications.

The aim of this work is to study the NO emissions under typical wildland fires conditions, paying special attention to the effect of the fuel-bound nitrogen. For this purpose, numerical simulations have been run using the PSR code from the CHEMKIN II package with a full mechanism (GDF-Kin® 3.0). Fuel bound-nitrogen has been included in the pyrolysis gaseous mixture of vegetation as NH3. Results have shown that if fuel-nitrogen is not considered on the pyrolysis mixture, NO emissions in wildland fire conditions are strongly under-estimated. Simulations results have been compared to experimental data.

POSTERSallowing cap-independent translation.The majority of these IRES-competent transcripts and their corresponding proteins are involved in tumor progression.Recently we described the IRESdependent translation of LamininB1 (LamB1) and its upregulation during epithelial to mesenchymal transition (EMT) of malignant hepatocytes.Now we focused on the role of IRES mediated LamB1 translation during hepatocellular carcinoma progression and its selective advantages compared to cap-dependent translation.Methods and Results: Polysome gradient analysis revealed LamB1 to be translationally upregulated upon hepatocellular EMT.The 5'untranslated region (5'-UTR) of LamB1 was competent to direct mRNA utilization in Renilla-Firefly luciferase and the beta-Gal-CAT bicistronic reporter assays.Additional assays for cryptic promoter or splice sites suggested that bicistronic reporter activities exclusively depend on internal initiation.In accordance, LamB1 levels increased upon induction of cellular stress and negative interference with cap-dependent translation.Enhanced translation of LamB1 in EMT transformed cells correlated with elevated IRES activity.In particular during initiation phase of EMT, IRES-mediated translation of LamB1 remained constant while cap-dependent translation was repressed.Time course analysis of Ras subeffector pathways revealed reduced MAPK and PI3K signaling during the initiation phase of EMT, while those pathways were stimulated after long-term treatment with TGF-beta.Interestingly, IRES-mediated translation of LamB1 increased upon inhibition of MAPK but not PI3K signaling suggesting that the activation of IRES translation is independent of MAPK.Conclusions: Together, these data show that the 5'-UTR of LamB1 contains an IRES which directs translational control of LamB1 during carcinoma progression.IRES mediated translation allows maintaining LamininB1-levels during the induction phase of hepatocellular EMT and upon cellular stress conditions.This activation of IRES translation seems to be connected with a downregulation of MAPK signaling.

Prescribed fires can be used as a forest management tool to reduce the severity of wildfires. Thus, over prolonged and repeated periods, firefighters are exposed to toxic air contaminants. This work consisted in collecting and analysing smoke released by typical Mediterranean vegetation during prescribed burning. Sampling was performed at five active zones on the island of Corsica. Seventy‐nine compounds were identified: volatile organic compounds and semi‐volatile organic compounds, including polycyclic aromatic hydrocarbons. Depending on exposure levels, the toxins present in smoke may cause short‐term or long‐term damage to firefighters’ health. The dangerous compounds emitted, benzene, toluene, ethylbenzene and xylenes, were quantified. Their concentrations varied as a function of the study site. These variations were due to the intrinsic and extrinsic characteristics of the fire site (e.g. plant species, fire intensity and wind). Our results show that benzene concentration is high during prescribed burning, close to the exposure limit value or short‐term exposure limit. Benzene can be considered as a toxicity tracer for prescribed burning because its concentration was above the exposure limit value at all the study sites. The authors suggest that respirators should be used to protect staff during prescribed burning operations.

The kinetics of thermal decomposition of a forest fuel was studied by thermogravimetry. Experiments were monitored under air and non-isothermal conditions from 400 to 900K. We used a classical model-free method, the Kissinger–Akahira–Sunose (KAS) method to calculate the activation energy vs. the conversion degree of the reaction on the whole temperature domain. Analyses were performed at 10, 20 and 30K/min. As expected, the complex structure of lignocellulosic fuels involved several steps with different energies in the degradation processes. The algorithm developed here, allows the calculation and the simulation of the solid temperature at different conversion degree for various heating rates. The good correlation between experiments and simulations validated the proposed algorithm. Then, kinetics parameters were used to perform simulations up to heating rates outside the functioning range of the thermal analyser.

An experimental study is conducted on the emission of volatile organic compounds (VOCs) emitted by Rosmarinus officinalis plants when exposed to an external radiant flux. The thermal radiation heats the plant and causes the emission of VOCs. The thermal radiation simulates the radiant flux received by vegetation in a forest fire. The results of the experiments are used in a simplified analysis to determine if the emissions of VOCs in an actual forest fire situation could produce a flammable gas mixture and potentially lead to the onset of an accelerating forest fire. The experiments consist of placing a plant in a hermetic enclosure and heating it with a radiant panel. The VOCs produced are collected and analyzed with an automatic thermal desorber coupled with a gas chromatograph/mass spectrometer (ATD-GC/MS). The effects of the fire intensity (radiant panel heat flux) and the fire retardant on the VOCs emission are then investigated. Two thresholds of the VOCs emission are observed. The first is for plant temperatures of around 120°C and appears to be caused by the evaporation of the water in the plant, which carries with it a certain amount of VOCs. The second one is around 175°C, which is due to the vaporization of the major parts of VOCs. The application of a fire retardant increases the emission of VOCs due to the presence of the water (80%) in the fire retardant. However, the use of the retardant results in a lower production of VOCs than using water alone. The measurements are used to estimate the concentration of VOCs potentially produced during the propagation of a specific fire and compared to the flammability limits of α-pinene. It is concluded that the quantities of VOCs emitted by Rosmarinus officinalis shrubs under certain fire conditions are capable of creating an accelerating forest fire.