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Pyrolysis is carried out by means of a packed bed, heated along the lateral surface at a moderate temperature (about 585 K), of a significant number of nut shells (pine, macadamia and Brazil nuts, hazelnut, walnut, almond, coconut, chestnut, peanut, and pistachio) and fruit stones (olive, nectarine, peach, plum, cherry, and apricot). With the exception of pistachio shells, the residues own fixed carbon (and C) and lignin/extractive contents higher than those of wood. The SEM images of chars reveal a nonporous vesicular or foamed tissue generally crossed by a very few large hollow vessels surrounded by bundles of small void fibers and/or hosting elongated rolled elements again of much smaller size. The EDX analysis indicates that the deposits, scattered on the charred tissue, are generally rich in potassium. As a consequence, secondary reaction activity is enhanced and, compared with wood, pyrolysis-induced overheating is always higher. However, despite the similarities, feedstock differences during pyrolysis are remarkable, as testified by maximum temperature overshoots between 60-225 K (versus 50K for wood) and severe pyrolytic runaway established only for about half of the samples.

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Packed-bed pyrolysis is carried out of beech wood preliminarily impregnated with potassium compounds (KOH, KCl, KC2H3O2, and K2CO3) for ion percentages corresponding to 0-1.8 wt %. The study is mainly aimed at examining the influence of the chemical state of potassium on the global thermicity of packed-bed conversion never examined before. The lowering of primary decomposition temperatures and the enhancement of secondary decomposition of tarry vapors is associated with a remarkable increase in the global exothermicity of the process which highly modifies the conversion conditions and product distribution. Maximum temperature overshoots over a large part of the bed, with respect to the programmed value of 605 K, reach 100-150 K and correspond to minima in the char yields. The quantitative effects are dependent on the content and chemical state of potassium which exerts its action via first the alkaline pretreatment and then catalysis. Moreover, thermogravimetric curves show that the diminution in the primary decomposition temperature is directly related to the K content and the basicity of the additive.

The pyrolytic conversion of industrial hemp ( Cannabis sativa ), subjected to various pretreatments, and its parts (woody core and fibers) has been investigated. For the conditions of thermal analysis, dominated by primary decomposition, the qualitative features of hemp and woody core devolatilization are practically coincident with those of wheat straw and beech wood, respectively. Retting and decortication significantly affect the magnitude and position of the peak rate and the char yield. Fiber decomposition, though reflecting the qualitative behavior of the majoritarian component cellulose, is deeply affected by hemicellulose/lignin/ash contamination. Packed-bed pyrolysis reproduces the qualitative similarities between hemp and wheat straw, on one side, and woody core and beech wood, on the other, mainly in relation to the thermal field (magnitude of reaction-induced overheating) with differences in the yields/composition of the lumped classes of products.

Thermogravimetric curves are measured, at heating rates of 5, 10 and 20 K/min under a nitrogen flow, of industrial hemp and shives, a by-product of bast fiber production, after water retting and mechanical decortication of the plant stalk. To understand the influences of the pretreatments, measurements are also made for water-retted and water-washed hemp, and shives obtained from manual decortication. Beech wood is used for comparison. It is found that a five-component degradation scheme (in number of two, one and two, for the pseudo- hemicellulose, cellulose and lignin, in the order) provides an excellent description in all cases. The kinetic parameters are affected more by pretreatments (retting and decortication) than chemical composition (hemp stalks or shives). Moreover, in addition to the quantitative similarities between shives and beech wood, the differences between hemp and shives can be taken into account by slightly higher activation energies of the latter for the second and third component (177 and 195 kJ/mol versus 160 and 177 kJ/mol), thus describing its higher thermal stability. The performances of a standard three-component scheme are also evaluated.

Kinetic models of beech wood decomposition, based on the three main pseudo-components, hemicellulose (one or two steps), cellulose (one step) and lignin (one or two steps), are applied for the first time to predict differential thermogravimetric (DTG) and differential scanning calorimeter (DSC) curves available from the literature. For the conditions that minimize the activity of secondary reactions, it is found that while the DTG curves are already well predicted by the extensively used three-step model, at least an additional step is required for the pseudo-lignin decomposition for a good prediction of the DSC data. The pseudo-cellulose decomposition is a globally endothermic process with the corresponding heat varying from about 601–528 J/g (of volatile evolved), as the number of reaction steps is increased from three to five. Pseudo-hemicellulose decomposition also takes place endothermally with reaction heats of 245 J/g (one step) or 321 and 226 J/g (two steps). Instead pseudo-lignin decomposition occurs with remarkable exothermicity corresponding to −923 J/g (one step) or −728 and −635 J/g (two steps).

Packed-bed experiments are conducted to examine the effects of moisture evaporation on the global exothermicity of hazelnut shell pyrolysis. Percentages typically reached from ambient conditioning (9-12 wt %, dry basis) do not modify the features of the pyrolytic runaway, with respect to bone-dry samples, apart from the obvious temporal delay. In fact, consequent to moderate external heating, moisture evaporation and solid decomposition take place sequentially. Instead, higher moisture contents lower the display of the reaction exothermicity, owing to the simultaneous occurrence of the two processes at different spatial positions. The interaction between the two is also highly dependent upon the thermal severity of the external heating. Finally, induced humidification by wetting small-sized particles (versus steaming), applied to achieve moisture contents above those of ambient conditioning, modifies the sample chemical properties, thus giving only a qualitative valence to the measurements.

The gaseous and liquid products of the fixed-bed pyrolysis of agricultural residues (hazelnut shells, olive pomace, straw pellets) and wood (beech wood and softwood pellets) are chemically characterized and compared. The heating temperature is varied in the range 473–800 K but the process occurs in the presence of large thermal overshoots. These reach their maxima for heating temperatures below (residues, overshoots up to about 225 K) or above (wood, overshoots up to about 85 K) approximately 650 K. Though mainly originated from secondary decomposition, overheating also highly enhances the primary decomposition rates, globally leading to short volatile residence times. As a consequence, the product distribution is modified. In particular, at low heating temperatures, also following pyrolytic runaway, the residues produce the largest amounts of volatiles and the yields of several condensable organic compounds (acetic acid, propionic acid, formic acid, hydroxypropanone, levoglucosan, guiacols and syringols) reach their maxima, with even qualitative deviations from the usual trends observed in pyrolysis.

The influence of the loaded zinc chloride content (0–11 wt %, dry sample basis) on the pyrolysis of beechwood particles packed in a bench-scale bed was studied. Given an external heating temperature of 655 K, the temporal profiles of the thermal field showed maximum values progressively increasing from 683 to 790 K as the catalyst content was increased from 0 to about 5 wt %. Based on cumulative char and water yields increasing from about 51 to 70 wt % and yields of condensable organics decreasing from about 35 to 15 wt %, the enhancement in the global exothermicity of the conversion process can be attributed to the successive predominance of dehydration with cross-linking reactions over depolymerization reactions. The exothermic effects were found to be qualitatively similar to but quantitatively lower than those associated with a sulfuric acid treatment. For higher acid contents and both additives, the noncatalytic effects associated with their loading were also found to contribute significantly to the ...

Thermogravimetric curves are measured, by means of a flexible home-made (HM) system, of the oxidation of wood chars generated from packed-bed pyrolysis at 800 K. A careful control of the sample temperature and a small mass/size (4 mg mass corresponding to 140micron thick particle layer) allow a kinetic regime to be established for heating rates between 5 and 10 K/min. Good quantitative predictions are obtained based on a two-step mechanism, with activation energies affected by the hardwood or softwood origin of chars (125–143 kJ/mol and 186–207 kJ/mol for the devolatilization and oxidation reaction, respectively). The same conditions applied for a standard commercial (SC) thermogravimetric system result into remarkable self-heating leading to uncontrolled ignition and too slow oxygen diffusion rates. Only extremely small sample masses (≤1mg) and slow heating rates (≤5K/min) permit to completely eliminate heat and mass transfer intrusions but the actual limits are strictly related to the specific char reactivity.

Potato plant waste pyrolysis is investigated by means of a cylindrical packed-bed reactor exposed along the lateral surface to heat fluxes of 20.6-33.2 kW/m2 (corresponding to heating temperatures, Ts, around 530-770 K). After an abrupt transition from torrefaction, a pyrolytic runaway regime is established (570 K 620 K when, in the presence of increasing radial gradients, a self-controlled pyrolysis regime is established with the reaction heat mainly exploited to preheat the bed.

A transient one-dimensional model, including the description of the chief chemical and physical mechanisms of the thermo-oxidative decomposition of poly(methyl methacrylate)/carbon nanotube composite and the parent polymer, combined with the critical mass flux criterion, quantitatively predicts the ignition times measured in a cone calorimeter. At low heat fluxes, the ignition times are longer for the composite, owing to the flame retardancy action of the carbon nanotubes resulting in the formation of a surface charred barrier, prior the attainment of sufficiently high rates of volatile release. Instead, at high heat fluxes, surface (versus in depth) absorption of the thermal radiation locally enhances the decomposition rate leading to shorter ignition times for the composite. Of paramount importance for the quantitative prediction of the ignition time is not only the empirical criterion (critical surface temperature or volatile mass flux) but also accurate kinetics taking into account the polymer properties, in particular the polymerization degree, and the presence of oxygen during the initial transient stage.

The pyrolysis of wastes from the production of cereals (rice husks, wheat and barley straw, spelt husk and straw, corn cobs, hulls and stalks) and protein and oil-protein crops (chickling vetch, lentil, chickpea and soybean straw and pods, sunflower stalks and husks) is investigated for the conditions of thermal analysis and packed-bed conversion. The differences in the thermogravimetric curves (heating rate 5 K/min) can be summarized by about 40–50 K for the peak temperature and 50–60 K for the temperature range where devolatilization occurs and by factors of about 2 and 1.6 for the peak rate and the char yield. They reduce when the comparison is limited to the same part of the plants, such as pods/husks and straws. Hot water washing emphasizes the qualitative similarity in the shape of the rate curves, which becomes the same as for hardwoods, and quantitatively reduces the differences in the peak rate. The different chemical properties of the feedstock also affect the magnitude of the reaction-induced overheating in the packed bed and consequently the yields of products though pyrolytic runaway never occurs.

Pyrolysis of KOH impregnated wood is investigated by means of thermogravimetric analysis and a packed-bed reactor. Apart from a confirmation in the trend of product yields and composition versus the additive content, profound modifications in the devolatilization curves and the bed thermal field are for the first time observed. For KOH contents up to about 1 wt %, the effects are essentially of catalytic type. The usual shape of the thermogravimetric curves is preserved though with a progressive displacement at significantly lower temperatures. For higher KOH contents, also associated with wood structure deterioration during aqueous impregnation, even the qualitative features are altered. The bed heating dynamics are strongly modified by the enhanced reaction exothermicity which, for high KOH contents, tend to turn the role of the external heat source simply into a starter for a self-sustaining process. The magnitude of the exothermic effect display, also including pyrolytic runaway, depends on the additive percentage and the heating conditions.

Pyrolysis is carried out using beech wood for packed beds, consisting of pellets and particles of various sizes, and a block in the same shape and size as the beds. The different physical properties of the samples affect the heat- and mass-transfer rates and, consequently, the conversion time. However, the effects on the yields and composition of the lumped product classes are generally negligible. An exception is observed for the packed beds made of pulverized material, where re-evaporation and pyrolysis of the vapors, previously migrated and condensed in cold zones, result in reduced yields of some organic products (hydroxyacetaldehyde, levoglucosan, syringols) and an increased carbon content of the char. These effects are enhanced by successively smaller particle sizes and more severe heating conditions.

The thermal degradation is modeled of a one-dimensional disk of poly(methyl methacrylate) (PMMA) with and without the dispersion of carbon nanotubes exposed to a fire-level heat flux. The description of the chief transport processes (conductive, convective and radiative heat transfer, convective mass transport) is combined with a one-step finite-rate reaction for polymer decomposition resulting in surface ablation (absence of nanotubes) or the formation of network-structured continuous layer of carbon nanotubes. Good agreement is obtained between the predicted and measured mass loss rates for the two cases. The presence of nanotubes reduces the peak in the mass loss rate and increases the conversion time, owing to the insulating effects of the surface layer and the much larger surface re-radiation losses. The effects of flame retardance are enhanced by increasing the growth rate and/or the thickness of the surface layer.

A comprehensive mathematical model is applied to simulate the effects of the input power and tar cracking on the pyrolysis of wood blocks for both microwave-induced and conventional heating. Despite of the highly different process dynamics for the two cases, the yields of the primary product classes (char, tar, gas) are comparable. Instead, while in the case of conventional heating the presence of secondary reactions leads to very low yields of the condensable products, these are always produced in high quantities in the other heating modality (50–56% for the typical kinetics of wood tar cracking). Also, the conversion times increase by a factor of about three (input power between 1500 and 500 W) and up to factors of 6–7 (input power 250 W) (versus factors of 3–16 for conventional heating).

Fir wood pyrolysis is carried out for extracted, KOH and KCl impregnated, and impregnated-extracted samples. For Kþ concentrations in wood of 0.14% (dry mass basis), the effects of KOH are quantitatively higher, but both additives produce a significant diminution in the yields of hydroxyacetaldehyde, furfural, and sugars, the decomposition temperature, and the conversion time. Water extraction of KCl impregnated samples is apt to reproduce again the characteristics of extracted wood pyrolysis. Instead, water extraction of KOH impregnated samples only reports the yields of hydroxyacetaldehyde, acetic acid, and hydroxypropanone to the original values whereas differences in the other variables, especially characteristic times and temperatures and levoglucosan yields, remain very large. Therefore, the action of the impregnated Kþ compounds during wood pyrolysis can be attributed to both irreversible modifications in the wood structure during impregnation, whose entity depends on the basicity of the aqueous solution, and intrinsic action of the Kþ ion on the activity of the decomposition reactions.

A detailed two-dimensional mathematical model is studied for the unsteady heat-and mass-transfer equations coupled with a quasi-steady formulation of the electromagnetic field for the microwave-induced pyrolysis of a wood block. The aspects examined include the description of the flow field based on either the assumption of constant pressure and one-dimensional flow velocity directed along the wood fibers or the linked two-dimensional variation of pressure and velocity in accordance with the Darcy law and deviations from the assumptions of local thermal equilibrium between the solid and gas/vapor phase. © 2011 American Institute of Chemical Engineers AIChE J, 52: 610–624, 2012

Packed-bed pyrolysis (heating temperature 800 K) is studied of beech and fir wood, several agro-industrial residues (corn cobs and stalks, olive husks, wheat straw, hazelnut and almond shells, orange peels, grape residues, artichoke stems, brewer's spent grain, and pruning cuts from cherry, olive, vine, and poplar trees) and cellulose, aimed at determining the potentially most promising feedstock for the production of furfural. Parameters associated with conversion dynamics are mainly affected by the packed-bed density (0.1-1.1 g/cm3) whereas products mainly depend upon the feedstock chemical composition. In particular, the yields of condensable organic products increase with the holocellulose content (10-85%) up to 25-40% (dry sample mass basis). The higher yields of furfural (dry organics mass basis), in the range 2-0.8%, are obtained from feedstocks with significant contents of cellulose/ pentoses (corn cobs, almond shells, hardwoods such as beech, cherry, olive, and poplar woods, orange peels, corn stalks, and hazelnut shells), while interesting quantities (approximately 1-0.4%) of 2(5H)-furanone are observed in all cases. As expected, the highest yields of hydroxyacetaldehyde and levoglucosan (about 8 and 3%) are produced from fir wood. On the other hand, some agro-industrial residues (hazelnut and almond shells and olive husks), apart from acetic acid, also produce high yields of phenolic compounds.

This study examines the effects of various pretreatments (size reduction, pelletization, hot water washing, torrefaction) on the pyrolysis of packed beds of hazelnut shells, exposed to moderate heating along the lateral surface, aimed at identifying the controlling or predominant mechanisms for the high reaction exothermicity leading to thermal runaway. As long as the particles preserve their chief structural properties (roughly or finely crushed shells), the process dynamics are not altered by size variation. Instead exothermic effects are highly reduced or almost disappear for milled shells, even in the pelletized form, depending on the actual powder size. Hence, secondary intraparticle reactions, owing to a peculiar scarcely porous microstructure, play a paramount role in the process exothermicity and thermal runaway. The displacement of the beginning of the reaction process at higher temperature, following sample washing, is enhanced by deepening the pretreatment. In this way sample conversion takes place in the presence of large spatial gradients, which hinder the occurrence of thermal runaway. Finally torrefaction, by partial or complete conversion of the more thermally labile chemical components, also eliminates the conditions that trigger and partly sustain the thermal runaway.

The sulfuric acid catalyzed pyrolysis of beech wood particles packed in a cylindrical bed, rapidly heated along the lateral surface, is carried out with special emphasis on the effects of the impregnated catalyst on the reaction heats (acid contents in wood between 0 and 11%). The complexity of the conversion process is augmented by the evaporation of the residual water not removed during the drying stage, owing to the formation of the sulfuric acid/water azeotrope and the endothermicity of acid decomposition. However, the overall exothermicity of wood decomposition is highly increased with maximum temperature overshoots, with respect to the heating temperature, that increase from 28 to 200 K and give rise, under appropriate conditions, to thermal runaway. The strong exothermicity of the decomposition process is attributable to the successive enhancement of dehydration, condensation and cross-linking reactions (char, water, and carbon dioxide formation) at the expense of depolymerization reactions (condensable organics formation). The changes in the depolymerization paths from low to intermediate acid concentrations, associated with a shift from levoglucosan formation to levoglucosenone, 1,4:3,6-dianhydro-?-d-glucopyranose, and furfural formation, do not appear to play a significant role in the process exothermicity.

The thermal decomposition of a cylindrical fixed bed consisting of agricultural residues (hazelnut shells, olive pomace, straw pellets) or softwood pellets, uniformly heated along the lateral surface, is investigated for heating temperatures in the range 473-800 K, and a comparison is made with results previously obtained for beech wood pellets. Although dependent on the external heating conditions, exothermic reaction heat effects are evident for all the biomasses, giving rise to maximum temperature overshoots of 225 K (hazelnut shells), 170 K (olive pomace), 78 K (straw), and 53 K (softwood pellets) (versus 86 K for beech wood pellets). For the first two materials and mild/moderate heating conditions, the entire bed volume experiences large temperature overshoots, so that the qualitative features of the pyrolytic conversion are those of a thermal runaway. Explanations are given, based on the different chemical and physical properties of the samples, for the different exothermicity level, and its implications in the practical application of torrefaction and pyrolysis are discussed.

Oxidative degradation and ignition of straw and rain-leached straw were investigated at a laboratory scale. Leaching reduced the ash content (by about 50 wt.%), in particular chlorine and potassium, and caused some swelling. A loose-packed bed (density 50 kg/m 3 ) was exposed to a forced flow (velocities in the range 0.34–1.9 m/s) of hot air (temperatures in the range 540–890 K). Degradation rates became significant for bed temperatures of about 500 K. However, the ignition temperatures were only slightly higher, hence oxidative degradation is a slow process, resulting in maximum conversions of about 50 wt.% (slightly lower for leached straw). Ignition temperatures increased, as the heating conditions were made more severe, and were lower for untreated straw, compared to leached straw. The ignition times were initially shorter and then longer for untreated straw, as the solid heating rate was increased. These results are due to a lower reactivity of leached straw, as a consequence of the partial ash removal, and its swelling, which modifies the heat transfer conditions across the bed.

A laboratory-scale countercurrent fixed-bed gasification plant has been designed and constructed to produce data for process modeling and to compare the gasification characteristics of several biomasses (beechwood, nutshells, olive husks, and grape residues). The composition of producer gas and spatial temperature profiles have been measured for biomass gasification at different air flow rates. The gas-heating value always attains a maximum as a function of this operating variable, associated with a decrease of the air-to-fuel ratio. Optimal gasification conditions of wood and agricultural residues give rise to comparable gas-heating values, comprised in the range 5−5.5 MJ/Nm3 with 28−30% CO, 5−7% CO2, 6−8% H2, 1−2% CH4, and small amounts of C2− hydrocarbons (apart from nitrogen). However, gasification of agricultural residues is more difficult because of bed transport, partial ash sintering, nonuniform flow distribution, and the presence of a muddy phase in the effluents, so that proper pretreatments are...

A new experimental system is presented to investigate the fast pyrolysis of solid fuels, in the absence of heat- and mass-transfer limitations. It consists of an electrically heated furnace, where a thin layer of powdered solid is exposed, on both sides, to radiative heating. A PID temperature controller is programmed for two different working conditions: the usual constant furnace temperature (A) and a constant sample temperature (B). Cellulose pyrolysis is investigated in the temperature range 523−699 K. It is shown that significant heat-transfer limitations cannot be avoided with the modality A, unless very slow heating rates, as in the classical TGA systems, are applied. In the modality B (global heating rates 19−56 K/s), the independence of the char yields from the sample thickness, for values of this below a critical value, indicates negligible spatial temperature gradients and activity of intraparticle secondary reactions of primary vapors. External heat-transfer limitations, due mainly to endothe...

The pyrolytic behavior of a cylindrical packed bed of beech wood pellets, uniformly heated along the lateral surface, is studied. As the heating conditions are varied, the trends shown by the mass loss rate and the yields of the lumped product classes are in agreement with previous literature. Moreover, detailed measurements of the thermal field permit, for the first time, the observation at the central core of the bed, of sequential (a) exothermic, (b) endothermic, and (c) exothermic effects. The examination of the corresponding temperature ranges indicates that they are linked, in the order, to the (primary and secondary) degradation of (a) hemicellulose, (b) cellulose and lignin, and (c) lignin. The dependence on the heating conditions is also explained of the center temperature overshoot (with respect to the steady value) which attains maximum values around 90 K.

A comprehensive transport model (conductive, convective and radiative heat transfer, convective mass transport) is applied to simulate the thermal decomposition of thermoplastic polymer/carbon nanotube nanocomposites and corresponding neat polymers (poly(methylmethacrylatye), polypropylene, polystyrene). The flame retardant effectiveness of nanocomposites is confirmed and good quantitative agreement with measurements is shown. The effects of flame retardance are enhanced by increasing the intensity of the radiative heat flux and/or the sample thickness. Moreover, extensive parametric and sensitivity analyses, carried out by varying kinetic constants and polymer physical properties, indicate that activation energy, density, reaction heat and thermal conductivity exert the most significant role. Finally a crucial aspect in relation to the differences in the initial degradation behavior of neat polymers versus nanocomposites is played by the in-depth radiation absorption coefficient. © 2013 Elsevier Ltd.

A detailed mathematical model, comprehensive of the main chemical and physical processes, is proposed for the open-core downdraft gasification of wood pellets, which permits a dual air entry: from the top section (primary air) and at a certain height of the packed bed (secondary air). A transition is simulated from a single, top-stabilized front (zero percentage of secondary air), to a double front stabilization (percentages of secondary air up to 60–70%) and finally to a single, forced center-stabilized front at the position of secondary air injection. For sufficiently high percentages of secondary air, following the complete or partial separation between the zone of primary wood degradation and a high-temperature, oxygen-rich zone and higher temperatures along the char bed, tar and char conversion is highly enhanced. Good agreement is obtained between model predictions and measurements for a pilot-scale plant.

The pyrolysis of particles of glucomannan, the main component of softwood hemicelluloses, is investigated in a fluidized-bed reactor. A first set of experiments is carried out for temperatures in the range 530-690 K to determine yields and composition of products. The most abundant are char, water, and carbon dioxide. The condensable organic fraction mainly consists of acetic acid, formic acid, hydroxypropanone, hydroxyacetaldehyde, and furfuryl alcohol. The second set of experiments is made to determine the weight loss characteristics of small samples exposed in the expanded bed at temperatures of 503-593 K that are then used to develop one- or two-stage pyrolysis mechanisms.

The absence of dystrophin in muscle fibers is associated with a major reduction in dystrophin-associated proteins (DAPs) and disruption of the linkage between the subsarcolemmal cytoskeleton and the extracellular matrix. We investigated the expression of the DAPs beta-dystroglycan, alpha-sarcoglycan, gamma-sarcoglycan and syntrophin as well as utrophin in the muscles of 13 Duchenne muscular dystrophy (DMD) carriers (with variable percentages of dystrophin-deficient fibers and with a range of clinical symptoms), 2 Becker muscular dystrophy (BMD) carriers (expressing a highly truncated protein in some fibers), 2 girls with a DMD-like phenotype, and 11 BMD carriers with almost normal dystrophin expression (reduced or patchy distribution in a few fibers only and rare dystrophin-deficient fibers). DAPs were highly reduced in all fibers lacking dystrophin in the DMD carriers, but were almost normal in the dystrophin-deficient fibers of the 2 BMD carriers with highly truncated dystrophin. In the 11 BMD carriers with nearly normal dystrophin, the few fibers with reduced or patchy dystrophin immunostaining also showed reduced DAP expression in correlation with dystrophin expression. Immunoblot for beta-dystroglycan and alpha-sarcoglycan confirmed the immunohistochemical findings. Utrophin expression was slightly increased in a proportion of fibers in the DMD and BMD carriers with dystrophin mosaicism. We found no correlation between utrophin expression and DAP expression. We conclude that absence or reduction of dystrophin in muscle fibers of DMD and BMD carriers causes a reduction of DAPs in the same fibers, as observed in DMD and BMD patients, while utrophin does not seem to play a role in DAP expression in adult muscle.

The coupled effects of particle size and external heating conditions (reactor heating rate and final temperature) on cellulose pyrolysis are investigated by means of a computer model accounting for all main transport phenomena, variable thermophysical properties and primary, and secondary reaction processes. The dynamics of particle conversion are predicted, and final product distributions are favorably compared with experimental measurements. A map is constructed, in terms of particle size as a function of the reactor temperature, to identify the transition from a kinetically controlled conversion to a heat transfer controlled conversion (thermally thin and thermally thick regimes) and from flash to slow-conventional pyrolysis. Conditions for maximizing oil, gas, or char yields are also discussed.

We report on a family with a boy affected by Duchenne muscular dystrophy (DMD) and an asymptomatic cousin with a Becker-type dystrophin abnormality, diagnosed by chance. Dystrophin gene analysis showed that these conditions were caused by two distinct deletions with breakpoints in different exons. In Xp21 families, DNA analysis and dystrophin testing of asymptomatic males with high CK plasma levels might detect different dystrophin mutations in separate haplotypes as in our family, although we stress there should be clear clinical or familial indications for such testing.

The problem of downward flame spread over composite, thermally thick materials is theoretically investigated by means of a thermal, analytical model and a numerical model based on the reactive fully elliptic Navier-Stokes equations. The solid, made of a thermoplastic polymer and inert additives, undergoes in-depth endothermic pyrolysis, for the active part, with volatile monomer formation. The effective thermal conductivity of the composite material depends on the content of inert and the variable content of the active part, whose thermal conductivity varies between that of the polymer and that of the melted phase monomer. Even though surface regression is not taken into account, polymer consumption is modeled through a mass balance. The changes in the flame spread mechanisms with solid phase properties are investigated. The spread process is strongly affected by the solid perpendicular (to the spread direction) thermal conductivity which, when it decreases, causes a continuous increase in the spread rate. On the other hand, both numerical and analytical solutions give no dependence of the spread rate on the solid parallel (to the spread direction) thermal conductivity for a wide range of variation. In agreement with previous experimental results, at very large values of the latter, the finite-rate reaction model predicts a decrease in the spread rate. However, in contrast to certain experiments performed for non homogeneous composite samples, an increase of the spread rate with the effective solid parallel thermal conductivity or thermal capacity has not been found.

Acidic pyrolysis of corncobs is carried out at 800 K in a packed-bed reactor using several catalysts (H2SO4, H3PO4, H3BO3, (NH4)2SO4, ZnCl2, NiCl2, MgCl2, and Fe2(SO4)3). In all cases, the yields of char, water, and some condensable organic compounds (acetic acid, levoglucosenone, 1,4:3,6-dyanhydro-?-D-glucopyranose, and furfural) are significantly increased at the expense of the phenolic and carbohydrate products typical of uncatalyzed pyrolysis. The maximum yields of furfural (FF) are around 5-6% for the H2SO4, Fe2(SO4)3 ,and ZnCl2 treatments, with potential further increase, following secondary degradation of the main anhydrosugars, up to 8.5% (H2SO4, Fe2(SO4)3) or 6.5% (ZnCl2). Additional experiments made with a wide range of Fe2(SO4)3 concentrations, and a comparison with previous results obtained for H2SO4 and ZnCl2 treatments indicate that the best performances are shown by the first catalyst with potential FF yields up to 10%. Moreover, at low concentrations, it also highly promotes the formation of levoglucosan, 5-methylfurfural, 5-hydroxymethylfurfural, 4-hydroxy-5,6-dihydro-(2H)-pyran-2-one, and 3-hydroxy-2-penteno-1,5-lactone, 1-hydroxy-3,6-dioxabicyclo[3.2.1]octan-2-one.

Devolatilization and oxidation kinetics of torrefied wood have been studied by evaluating thermogravimetric curves measured in nitrogen and air at various heating rates. Samples consist of Norway spruce wood chips torrefied at several process temperatures and residence times. Data about untreated wood have also been obtained for comparison. Measured curves are well predicted by means of a five-reaction mechanism, consisting of three devolatilization reactions for the pseudo-components hemicellulose, cellulose and lignin and, in air, of two additional reactions for char devolatilization and combustion. The torrefaction pre-treatment only requires model modifications in the amounts of volatiles generated from the decomposition of pseudo-components, indicating that only their relative percentages and not their reactivities are modified. On the other hand, a slightly different thermal stability is found for the char generated from torrefied wood, which results in higher activation energy and lower reaction order for the oxidation step. Hence torrefaction conditions can affect the subsequent conversion characteristics of the char product.

The acid catalyzed pyrolysis of corncobs is investigated for the production of chemicals (in particular furfural) and bioproducts. Particles, pre-impregnated with H2SO4 concentrations up to about 4% (dry sample mass basis) and pre-dried at 343K, are exposed in the form of a packed-bed at a heating temperature of 800K. The gas release rate remains approximately constant, at a value about the half with respect to the maximum detected for acid-free samples, for a large part of the process transients. Conversion times are roughly increased by 50% while reaction temperatures, on the average, become lower by about 20-40K. Dehydrating and charring reactions become successively more favored suppressing the formation of condensable organic compounds. A decay is observed in the yields of both some carbohydrates (hydroxyacetaldehyde, hydroxypropanone, furfuryl alcohol, etc.) and phenolics (phenol, guiacol, 4-methyguaicol, 4-ethylguaicol, syringol) although less steep for the latter. However, catalyst concentrations below 0.5% lead to maxima in the yields of levoglucosan, 5-hydroxymethylfurfural and 1,6-anhydro-?-D-glucofuranose. Moreover, the production is significantly enhanced of levoglucosenone (from trace amounts up to 4.5%) and furfural (from 0.65% up to 5%) at catalyst concentrations around 1-2% and 2-3%, with 1,4:3,6-dianhydro-?-D-glucopyranose (maximum yield 0.65%) acting as a reaction intermediate. The yield of acetic acid remains constant at 4% up to catalyst concentration around 3%. Higher catalyst concentrations are associated with a rapid decline in the yields of all these organic compounds with the total amount of char, carbon dioxide and water reaching 70%.

The pyrolysis of corncobs impregnated with variable amounts of zinc chloride (ZnCl2) (up to 11%, on a dry sample mass basis) is investigated and compared with fir wood results. As expected, a continuous increase with the amount of impregnated catalyst in corncobs is observed of the formation rates of char and water (total yields from 46% up to 64%) associated with a decline in the yields of organic condensable products (from 38% to 18%) and gas (from 13% to 9%). Moderate ZnCl2 concentrations (2%−5%) favor the production of levoglucosenone (from trace amounts to 1%), acetic acid (from 4% to 6%), and furfural (from 0.65% to 6%). Moreover, low values, although causing the prompt decay in the yields of hydroxyacetaldehyde, hydroxypropanone, levoglucosan, minor carbohydrates, phenols, and guaiacols, enhance the formation rate of 5-hydroxy-methylfurfural, 4-hydroxy-5,6-dihydro-(2H)-pyran-2-one, 1-hydroxy-3,6-dioxabicyclo[3.2.1]octan-2-one, and 1,4:3,6-dianhydro-α-d-glucopyranose. Results support the speculation...

A theoretical model describing the behavior of a thermally thin cellulosic sheet heated by external thermal radiation in a quiescent microgravity environment is developed. This model describes thermal and oxidative degradation of the sheet and the heat and mass transfer of evolved degradation products from the heated cellulosic surface into the gas phase. At present, gas phase oxidation reactions are not included. Without buoyancy, the dominant vorticity creation mechanism in the bulk of the gas is absent except at the material surface by the requirement of the no-slip condition. The no-slip condition is relaxed, permitting the flow to be represented by a velocity potential. This approximation is permissible due to the combination of a microgravity environment and low Reynolds number associated with slow small-area heating by external radiation. Two calculations are carried out: heating without thermal degradation, and heating with thermal degradation of the sheet with endothermic pyrolysis, exothermic thermal oxidative degradation, and highly exothermic char oxidation. The results show that pyrolysis is the main degradation reaction. Moreover, self-sustained propagation of smoldering for cellulosic materials is very difficult due to the lack of sufficient oxygen supply in a quiescent environment.

Momentum, energy and chemical species balances for the gas phase coupled to momentum and energy balances for the liquid phase are used to model hydrodynamics and flame spread across liquid fuels. The unsteady formulation of the two-dimensional model equations including the buoyancy and surface tension variation effects, the description of liquid fuel vaporization as well as of finite rate combustion kinetics has allowed the simulation of oscillatory spread rate conditions. This behaviour has been observed, in agreement with experiments, for fuels at low initial temperature (below the flash point) when surface tension driven flows are established in the liquid phase. The role played by the liquid phase convective motions and by the structure of the gas phase flow field for the type of spread observed has been investigated by varying the liquid viscosity and the mechanisms controlling whether the spread is uniform or pulsating have been determined.

A one-dimensional unsteady mathematical model of solid fuel ignition is presented. The solid fuel is heated by an external radiative heat source. Some radiation is absorbed in depth by the solid fuel and some by the decomposition products in the gas phase. Solid fuel degradation occurs according to a zero-order Arrhenius pyrolysis reaction and gas-phase combustion according to a second-order Arrhenius reaction. Gas-phase heat and mass transfer and solid phase heat transfer are described by differential balance equations that are coupled through the boundary conditions at the interface. The solution is computed numerically by an implicit finite difference method. PMMA radiative ignition is simulated by varying the intensity of the radiative heat flux and predictions show quite good agreement with experiments. The ignition process oceurs in the gas phase in a premixed fashion, rapidly followed by the transition to a diffusion flame. As the radiative heat flux is increased, higher surface temperatures and pyrolysis mass fluxes are reached, ignition occurs closer and closer to the fuel surface, and ignition delay times decrease. Gas-phase absorption of radiation plays a fundamental role in the predicted ignition phenomenon and ignition delay times. In particular, with realistic data and no absorption of radiation in the gas phase, ignition does not occur at all. Finally, a parametric study is performed in order to analyze the dependence of the predicted ignition phenomenon on key parameters used to model degradation and combustion processes, such as preexponential factors and activation energies of the reactions.

The main physical and chemical processes of flame spread across laminar liquid fuel pools (heat and mass transfer, hydrodynamics, liquid fuel vaporization and gas phase finite rate reaction) are described by unsteady, two-dimensional, fully elliptic, balance equations for both the liquid phase and the gas phase. Solution is computed by a semi-implicit finite difference method. The flame spread over alcohol fuels at low initial liquid temperature is studied. Predicted flame structure changes from a premixed type at the leading edge to a diffusive type downstream. Recirculation is observed both in the liquid phase and, ahead of the flame, in the gas phase. Convective motions in the liquid precede flame spread and play a very important role in the pre-heating of the liquid. In agreement with experiments, as the initial liquid temperature is decreased, the flame motion turns from uniform spread, when liquid-phase convective heat uniform spread. The controlling mechanisms and the interactions between liquid phase phenomena and gas phase phenomena, responsible for the changes in the type of spread, have been determined.

Hyperventilation is a widely used EEG activation method. Aim of the study was to evaluate the modifications in brain connectivity due to hyperventilation in normal subjects and in cryptogenic focal epileptic patients. We examined EEG recordings from 19 scalp electrodes of 22 normal subjects and 22 focal cryptogenic epileptic patients. Exclusion criteria were: migraine, cerebrovascular disease, MRI abnormalities and use of drugs, apart from Antiepileptic drugs in epileptic group. We selected segments before (PRE), during (HYPER) and five minutes after (POST) hyperventilation. We analyzed neural generators through low resolution electromagnetic tomography (sLORETA) for the following bands: delta (1–4 Hz), theta (5–7 Hz), alpha (8–13 Hz), beta (14–30 Hz) and gamma (31–60 Hz). We also computed EEG lagged coherence between 19 Regions Of Interest for the same bands. Finally, we performed intergroup analysis of Mean Lagged Coherence. In both groups hyperventilation significantly increases EEG ( p p p

s of Poster Presentations / Clinical Neurophysiology 125, Supplement 1 (2014) S1–S339 S145 behavioural patterns and neural substrates of aphasic and apraxic deficits after left-hemispheric stroke, neuropsychological testing and statistical lesion analyses were performed in 50 sub-acute stroke patients. Methods: Eight neuropsychological tests were administered to detect and characterise aphasic and apraxic deficits. Voxel-based lesion symptom mapping (VLSM) was performed to identify lesion sites associated with aphasic and apraxic deficits as well as combinations thereof. Results: Behaviourally, half of all patients or two-thirds of the 37 aphasic patients suffered from co-morbid aphasia and apraxia. While 24% (n=12) of the patients exhibited aphasia without apraxia, apraxia without aphasia was rare (n=2, 4%). As expected, VLSM revealed that aphasic deficits were associated with lesions to left inferior frontal, superior temporal and supramarginal gyrus. Apraxic deficits correlated with lesions to left inferior frontal gyrus, the central region, and parietal lesions for imitation. Lesions to the opercular part of the left inferior frontal gyrus (i.e. Brodmann’s area 44 as part of Broca’s region) led to combined apraxic and aphasic deficits. Conclusions: This is the first study which demonstrates the lesion site for comorbidity of aphasia and apraxia. Our findings stress the importance of Brodmann’s area 44 (as part of Broca’s region) as an interface between language and praxis. P367 High frequency deep rTMS over the right homologous Broca’s region improves naming in chronic post-stroke aphasia: a pilot study R. Chieffo1, F. Ferrari1, P. Battista1, E. Houdayer1, A. Nuara1, F. Alemanno1, J. Abutalebi1, A. Zangen2, G. Comi1, S.F. Cappa1, L. Leocani1 1Scientific Institute Hospital San Raffaele, Milan, Italy, Italy; 2Department of Life Sciences Ben-Gurion University, Beer-Sheva, Israel, Israel Objective: This study aimed to compare the effect of excitatory, inhibitory and sham rTMS delivered with H-coil over the right inferior frontal gyrus (IFG) in chronic post-stroke aphasic patients. Methods: Five right-handed post-stroke aphasic patients underwent a picture naming task before and immediately after each of three sessions of rTMS: excitatory (10 Hz), inhibitory (1 Hz) and sham rTMS, in random sequence and separated by at least one week. Results: Only the excitatory 10 Hz stimulation was associated with a significant improvement in naming performance, (p=0.043) and was significantly more effective than 1Hz rTMS (p=0.043). Conclusions: A single session of excitatory deep brain rTMS over the right IFG with H-coil significantly improves naming in right-handed chronic post-stroke aphasic patients. This result is in line with the hypothesis of a positive, rather than detrimental role, of the right hemisphere in chronic aphasia due to a left-hemispheric stroke. P368 Association between dysphagia and OSAS in acute stroke patients C. Di Blasi, G. Della Marca, A. Broccolini, F. Pilato, P. Profice, G. Frisullo, P. Caliandro, R. Morosetti, V. Brunetti, N.M. Giannantoni, E. Testani, A. Losurdo, V. Gnoni, P.M. Rossini Catholic University, Geriatric, Neuroscience and Orthopedic, Rome, Italy Introduction: Co-occurrence of dysphagia and Obstructive sleep apnoea (OSAS) may negatively impact clinical course in stroke. Objective: The objective of this study is to evaluate the correlation between dysphagia and sleep apnoea in acute stroke patients. Methods: Inclusion criteria: ischemic or hemorrhagic stroke (≤48 hours). Exclusion criteria: NIH stroke scale

Background Acute pericarditis is defined as at least 2 of the following: typical chest pain (sharp and pleuritic, improved by sitting up and leaning forward), pericardial friction rub, suggestive EKG changes (widespread ST elevation or PR depression), new or worsening pericardial effusion. Pericarditis may recur in 15-30% of cases; these children are frequently followed by pediatric Rheumatologists. At present the largest case series described 15 children affected by recurrent pericarditis. Objectives This is a multicenter, retrospective cohort study including all consecutive cases of recurrent pericarditis with at least 2 recurrences in pediatric patients seen in 7 referral centers in Italy. Methods We analyzed 107 children; the mean age at the time of the first attack was 11,1 years; 67 were males and 40 females. Results The mean recurrence number was 4.8 (2-25); pericarditis was idiopathic in the majority of cases (88%), post-pericardiotomic in 10%, related to Familiar Mediterranean fever in 2%. Most children had fever and CRP elevation at disease onset (77% fever, 93% CRP elevation), and so was pericardial effusion (76%: typically mild, with cardiac tamponade in 13%, only at disease onset), while pericardial rub and EKG changes were detected in a smaller number of patients (28% and 45% respectively). After a mean follow-up of 73 months, none of the patients with idiopathic RP developed a systemic autoimmune disease (even if ANA was positive in 19%) or was found as having an infectious disease. 80% children were treated with NSAIDs, 64% with steroids and 63% with colchicine. Refractory cases were treated with immunosuppressant drugs (AZA: 4, MTX: 2, IVIG: 1, Antimalarials: 5, CSA: 1), and 11 with Anakinra. Children treated with corticosteroids experienced more recurrences (5,9 vs 2,6, p Conclusions This is the largest ever published case-series on pediatric recurrent pericarditis. Because of lack of standardized treatment guidelines, we believe that our data will help clinicians in manage these children, typically treated with rheumatological drugs. Corticosteroids should be used with extreme caution and NSAIDs remain the mainstay of the therapy. Anti-IL1 may be useful in very selected cases. The long term outcome is good. References Imazio M, et al. A randomized trial of colchicines for acute pericarditis. New Engl J Med 2013; 369:1522-8. Gaspari S. et al. New insights in the pathogenesis and therapy of idiopathic recurrent pericarditis in children. Clin Exp Rheumatol 2013;31:788-94. Raatikka M et al. Recurrent pericarditis in children and adolescents. Report of 15 cases. J Am Coll Cardiol 2003;42:759-64. Disclosure of Interest None declared DOI 10.1136/annrheumdis-2014-eular.1952