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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.

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.

In recent decades, the European populations of wild boar have grown substantially, as has the impact of this species, owing above all to its rooting activity. Our aim was to investigate the relationships between vascular plant understorey and wild boar rooting intensity. The questions we addressed are: does rooting intensity influence understorey species composition and diversity? Which functional traits are associated with different levels of rooting? We performed a comparative analysis of plant communities in areas with contrasting levels of rooting intensity within a Mediterranean deciduous lowland forest in central Italy. Besides comparing species composition and diversity, we tested the association between species traits and rooting levels through fourth-corner analysis. We found that contrasting levels of rooting were associated to different understorey species composition and evenness, while we observed no significant difference in species richness. In contrast with our expectations, sites with lower rooting returned i) lower evenness values and ii) a higher proportion of species characterized by traits related to resistance or response to herbivory, i.e., spinescence, clonality, endozoochory, underground storage organs, and low height values. Our findings suggest that current vegetation patterns partly depend on the legacy effect of past rooting disturbance, since the areas currently subjected to low rooting intensity were likely to be intensely rooted in the past. These areas may have developed a marked dominance of clonal thorny species that, in turn, inhibited further feeding activities by wild boar.

Wild boar (Sus scrofa) rooting activities may affect several taxonomic groups. In hardwood forests, wild boar’s diet is predominantly represented by plants of the ground layer. We here report a study conducted in two Mediterranean lowland forests in central Italy (the State Reserve of Castelporziano and the Circeo National Park). The aim of our study was to evaluate whether contrasting levels of rooting (high vs. low) determine different understorey species composition and diversity. Our results show that different rooting levels determine strong differences in the understorey composition. Furthermore, we found that the occurrence of different species (e.g. Ruscus aculeatus) was associated with contrasting rooting levels. Mediterranean species were significantly more frequent in plots with high levels of rooting. Plots sampled in the Castelporziano area were also characterised by species adapted to frequent disturbance and anthropogenic influence (e.g. Piptatherum miliaceum, Conyza albida); whereas species associated to low-rooting plots were typically related to deciduous forests. We found non-significant differences in diversity indices. This study demonstrates that wild boar activities cause substantial alterations in plant communities and underscores the need for long-term exclosure experiments.

The identification of the drivers of diversity in understorey plant assemblages is a major challenge in forest ecology. However, it is not yet fully understood whether the same factors consistently affect different facets of species organization, such as species richness, composition and turnover. Here, we compare the influence of fine-scale environmental variables and spatial organization on the herb-layer flora of two unmanaged and ecologically different forest stands in the Muniellos Biosphere Reserve, Northern Spain. The aims of our study are to identify the most important factors influencing different facets of herb-layer plant organization, and to test whether the effect of such drivers is consistent across facets and forest types. We used Generalized Linear Models, Redundancy Analysis and Multiple Regression on Distance Matrices to model, respectively, the response of species richness, species composition and species turnover to spatial distances as well as to several environmental factors, including forest structure, light conditions, soil and topographical features. We observed a substantial consistency among variables affecting the different facets of ground-layer species organization within stands, with a subset of topographical variables with a transversal effect across facets. Although potential solar radiation was the main variable influencing species richness in the two stands, the factors shaping species composition and turnover varied across forest types: in the beech stand, slope and canopy openness were the main determinants of herb-layer species diversity and turnover; in the oak stand, the main drivers of species composition were related to topography and spatial structure, while spatial distance was the main driver of species turnover. Our study shows that the ecological processes driving fine-scale variation of ground-layer plant richness and composition are similar to those driving species turnover. Although the ecological factors shaping different facets may be the same, we highlight that, at least in temperate forests, these factors are system-specific and vary according to forest types.

We performed a gap analysis of protected area networks in Italy to assess the representativeness of potential natural vegetation (PNV) types of the European Natura 2000 network compared with the National Protected Area network. In this context, the PNV map, reflecting the diversity and spatial arrangement of the natural terrestrial ecosystems, can be considered as an appropriate proxy of environmental and biogeographical diversity of Italy. In this country, 775 protected areas are registered in the Official List of Protected Areas (OLPA), 2281 sites are listed as Sites of Community Interest and 590 as Special Protection Areas, constituting the Natura 2000 network. The adopted conservation target considered that any PNV type included for less than the 10% in the PAs network (OLPA, Natura 2000) was defined as a gap in the system. In particular we defined four categories of PNV protection: any PNV types with a representation of less than 10% in both the OLPA and N2000 was defined as a “total gap” (i.e., under-protected); any PNV type with a representation of less than 10% in either the OLPA or the N2000 was defined as a “partial gap”; any PNV type with a representation of between 10 and 50% in both the OLPA and N2000 was defined as “protected”; lastly, any PNV type with a representation of more than 50% in both the OLPA and N2000 was defined as “widely-protected”. Digital overlays of PNV and PAs networks were separately performed and statistics produced, indicating the current state of protection of Potential Natural Vegetation types in the two networks (OLPA and Natura 2000). We found that more than 59% of PNV types recognized on the Italian territory is not protected by the OLPA network. On the contrary, regarding Natura 2000 network, 68% of PNV types are protected, accounting for 27% more than OLPA. Compared to the National network of OLPA, the European network Natura 2000 is characterized by a larger percentage of territory in terms of area (18% of the Italian territory for Natura 2000 vs 10% of OLPA) but also by a smaller size of the sites, allowing for a more coherent distribution and efficiency in the protection of habitat remnants (68% PNV types protected by Natura 2000 vs 41% by OLPA). The proposed PNV approach can help guiding decisions on where and how to spend scarce conservation management resources.

Weight loss curves of wood fast pyrolysis oils in air have been measured, under controlled thermal conditions, carrying out two separate sets of experiments. The first, which has a final temperature of 600 K, concerns evaporation/cracking of the oil and secondary char formation, processes associated with sample swelling and solidification. After collection and milling, in the second set of experiments, heterogeneous combustion of the secondary char is carried out to temperatures of 873 K. Although the details of the rate curves appear to be dependent on the commercial process (BTG, Dynamotive, Ensyn, Pyrovac) applied to produce the oil, the same qualitative features are observed in all cases. Secondary char formation and sample modification begin for temperatures of about 460−490 K. Moreover, a conceptual reaction mechanism, consisting of six main zones, can always explain the low-temperature (≤600 K) devolatilization characteristics. Similar to primary char produced from wood pyrolysis, secondary char exhibits weight loss curves that present a devolatilization stage and a combustion stage, but with a significantly lower reactivity, as a consequence of a physical structure completely lacking micropore networks.

The variations in chemical composition and the effects of sample origin and pretreatments represent a major problem in the kinetic modeling of wood pyrolysis. This study aims to a deeper understanding of these issues by examining a species, chestnut (Castanea sativa), that contains a higher amount of extractives than the common forest hardwoods of the temperate zone. Thermogravimetric and kinetic analyses were carried out on five chestnut samples obtained from plants grown in France, Italy, and Russia. The results were compared to that of a widely used and investigated species (beech) belonging to the same plant family. Degradation takes place over a narrower range and at lower temperatures, giving higher yields of char. In all cases, hot-water washing causes a decrease in the fixed carbon content and char yield, an increase in the peak rate, a better separation between pseudo-component dynamics, and a displacement of the reaction zones toward higher temperatures. Though with some scatter and quantitatively lower, the same effects are also observed as a consequence of acetone extraction. Both pretreatments act to reduce the differences between chestnut samples and with beech, but peculiarities due to origin and species are preserved. The three parallel reaction mechanism for the hemicellulose, cellulose, and lignin, with the same activation energies previously determined for other hardwood species by Grønli et al. (Ind. Eng. Chem. Res. 2002, 41, 4201) is still acceptable for engineering applications. In contrast, predictions of the process details require single curves evaluations, resulting in kinetic data specific to sample origin, except for the activation energy of the lignin devolatilization step. Kinetic parameters also indicate that the lower char yields, associated with pretreatments, are chiefly due to alterations in the cellulose decomposition kinetics, whereas the effects on the other two components nearly compensate each other. Finally, reliable evaluations are provided of experimental uncertainties associated with repeatability of experiments and reproducibility of sample properties.

SummaryThe forest vegetation of Colchis has been described by some Western European phytogeographers as broad-leaved evergreen. However, this was due to a lack of information. Scientists from Western Europe were not allowed to carry out field studies in Georgia until the country became independent, while no paper in English was available until 1999. Here we present some phytogeographical observations on the Colchic forest based on a study trip undertaken in Colchis and on data contained in papers not easily found in libraries. We show that the Colchic forest is a deciduous forest dominated by Fagus orientalis, Castanea sativa, Carpinus betulus, Alnus glutinosa ssp. barbatain varying proportions depending on altitude and soil, with a thick evergreen shrub layer composed mainly of Rhododendron ponticum, Prunus laurocerasusand Ilex colchica.No evergreen species reach the tree layer, except the lianas Smilax excelsaand Hedera colchicaand, at higher altitudes, the conifers Abies nordmannianaand Picea orientalis.The floristic composition shares most genera and many species with European deciduous forests; from a phytosociological point of view, most forest communities in Colchis belong to Querco robori-Fagetea sylvaticae.Thus there is no “laurisilva” in Colchis, nor is there any floristic, physiognomic or bioclimatic similarity between the Colchic forest and the Macaronesian laurel forest, which is composed entirely of evergreen trees belonging, in the main, to Lauraceae.In his overview of the vegetation belts of Italy published in 1979, S. Pignatti proposed a “Colchic Belt” which he defined as a relict vegetation belt “characterized by the dominance of a temperate evergreen laurophyllous forest (…) which is still well preserved in Colchis.” Over subsequent years frequent reference has been made to this belt in Italian phytosociological and phytogeographical literature. However, since there are no laurophyllous forests in Colchis, we propose that the concept of a “Colchic Belt” should at least be redefined.

We propose a simple mathematical framework to define consistently the environmental quality of a given landscape based on the relative abundances of the constituting land cover classes. Unlike traditional diversity measures, the new method does not evaluate the simple dispersion of the relative abundances of land cover classes, but assigns a weight to each land cover class according to the rank along a gradient of environmental quality. To clarify the ideas discussed, the method is illustrated with data from a pilot study to assess landscape changes in an Italian periurban area over the last 50 years.

Conventional pyrolysis of beech wood has been carried out for heating temperatures in the range 600−900 K, reproducing conditions of interest in countercurrent fixed-bed gasification. The yields of liquids (water and tars) increase with the heating temperature from about 40 to 55% of dry wood mass, confirming results previously obtained with a laboratory-scale gasifier. Apart from qualitative identification of ~90 species, GC/MS techniques have been applied to quantify 40−43% of tars (40 species, with major contributions from acetic acid, hydroxypropanone, hydroxyacetaldehyde, levoglucosan, formic acid, syringol, and 2-furaldehyde). Decomposition of holocellulose leads to the formation of furan derivatives and carbohydrates, with a temperature-dominated selectivity toward hydroxyacetaldehyde against levoglucosan. Syringols and guaiacols, originating from primary degradation of lignin, present a maximum for heating temperatures of about 750−800 K whereas, owing to secondary degradation, phenols continuously increase. A comparison is also provided with fast pyrolysis liquids obtained from four commercial plants.

The unreacted-core-shrinking approximation is used to model one-dimensional transport phenomena and finite-rate kinetics of thick wood pyrolysis. A quasi-steady-state formulation of the equations is suggested because the effects of process transients along the charred region are shown to be negligible. Temperature dynamics of the unreacted core are described with either a concentrated-parameter model or a distributed-parameter model combined with an integral solution method. Though both treatments produce qualitatively similar predictions, only in the latter case is good quantitative agreement obtained with measurements of volatile release characteristics (external radiative heat fluxes in the range 40−80 kW/m²). Depending on material properties and reaction kinetics, convective heat transfer may play an important role in the particle heating rate and conversion time. The model shows significant sensitivity to the activation energy of the pyrolysis reaction, the effective thermal conductivities of wood and char, and the wood thermal capacity.

Thermogravimetric curves have been measured at a heating rate of 5 K/min for several hardwoods (beech, alder, birch, and oak) and softwoods (Douglas fir, two pine species, redwood, and spruce), whose chemical composition varies within the usual standards. The analysis of the devolatilization characteristics is based on the introduction of several reaction temperatures. A comparison between hardwoods and softwoods shows that, in the latter case, the decomposition starts at lower temperatures, the hemicellulose shoulder is more delayed, and both the hemicellulose and cellulose zones are wider. Furthermore, the yields of char are higher. However, a devolatilization mechanism, consisting of three parallel reactions and the same set of activation energies for hemicellulose, cellulose, and lignin (100, 236, and 46 kJ/mol), can describe the high-temperature (>553 K) degradation behavior of all of the woods with a good accuracy. Modifications for the extension of the mechanism at lower temperatures are required only for species with significant extractive contents and consist of two further reactions (activation energies of 105 and 127 kJ/mol, respectively).

The combustion kinetics of a laminate with intumescent behavior were determined by thermogravimetry for heating rates between 5 and 20 K/min and a final temperature of 873 K. The devolatilization stage consists of three consecutive first-order reactions that can be associated with the release of (1) water vapor (from aluminum trihydrate), (2) HCl (from polychloroprene), and (3) a gaseous mixture (from expansible graphite), followed by charring. The corresponding activation energies are 114, 140, and 83 kJ/mol. The second stage is the heterogeneous combustion of the active part of the intumescent char. This process is described by a one-step reaction whose rate presents a power-law dependence (n = 1.98) on the solid conversion and an activation energy of 182 kJ/mol. The thermal response of a composite system that uses the intumescent material as a coating for thin steel slabs was also investigated. For external temperatures of 625−1025 K, the sequential chemico-physical changes undergone by the intumescent coating highly affect the dynamics of steel heating.

Weight loss curves of thin layers (150 μm) of beech wood powder, measured for heating rates of 1000 K/min and final temperatures in the range 573−708 K, show final char yields of 37−11%. The process is kinetically controlled and, for the most part, isothermal. A one-step global reaction, with E = 141.2 ± 15.8 kJ/mol and ln A = 22.2 ± 2.9 s^-1, is a degradation mechanism capable of capturing the main features of the process. The thermogravimetric curves also allow the formation rate constants to be estimated for char and total volatiles (activation energies of 111.7 ± 14.3 and 148.6 ± 17.4 kJ/mol, respectively) and, once integrated byproduct distribution, those for liquids and gases (activation energies of 148 ± 17.2 and 152.7 ± 18.2 kJ/mol, respectively). A comparison is provided with pyrolysis mechanisms available in the literature.

Bulk borosilicate glasses were prepared by the sol−gel process and doped with gold nanoparticles. First, a sol of the host glass (with nominal molar composition of 10% B2O3−90% SiO2) was prepared, and then gold was introduced into the sol by means of a solution of a Au³⁺ complex. The resulting gels were dried at 60 °C and then heated in air at various temperatures up to 600 °C to nucleate the gold particles and sinter the glass matrix. Various gold ligands were tested, and thiourea was found to be the most effective ligand in preventing fast gold reduction and precipitation to the gel surface during drying. A model based on the formation of insoluble gold species during drying of the gel is discussed to explain the phenomenon of gold precipitation to the sample surface. The heated gels were studied by measurements of the BET specific surface area and of the apparent density, showing the densification of the matrix during the heat treatments. UV−vis optical absorption spectroscopy was used to monitor the formation of Au nanoparticles that was effective after heating the gel at 300 °C in air. TEM studies revealed that two kinds of Au particles were present, with mean sizes of 10 and 30 nm. The smaller particles have a lattice spacing corresponding to face-centered cubic Au, whereas electron nanodiffraction patterns of the larger particles exhibit features of orthorhombic Au3Si.

Nonsense mutations outside the splicing consensus sequence have been reported to cause skipping of the nonsense-containing exon in several human diseases. We describe, for the first time, nonsense-mediated exon skipping in the laminin alpha2 (LAMA2) gene. Two siblings from a consanguineous family had altered expression of the laminin alpha2 chain and moderate clinical manifestations. In both we identified the new nonsense mutation Arg744Stop, which we expected to result in a totally non-functional polypeptide. However, analysis of the transcript revealed skipping of exon 15, containing the mutation, even though the consensus sequences for splicing at both ends of the exon and the beginning of intron 15 were unaltered. Exon skipping restored the open reading frame of the mutant transcript and resulted in a truncated protein. In cases where the genetic findings do not elucidate the phenotype, mRNA analysis is necessary to clarify the primary effect of mutations. Our findings also point to the necessity of immunochemical screening for expression of laminin alpha2 chain in atypical dystrophic adults as well as children.

Structure and diversity trends (β-diversity and species richness) across the Fagus sylvatica timberline in the central Apennines were investigated. Twenty-three belt transects were laid out across the upper forest line in the Simbruini Mountains. Number of species, plant cover, and height of different layers were recorded in each quadrat. The moving split-window method was used to detect ecological discontinuities across beech timberlines. We show how β-diversity changes along timberlines and we put forward some hypotheses about the possible dynamics of these transitions. Fourmodels resulted from the analysis of β-diversity trends: two β-diversity peaks indicated a transition where shrubs, mainly Juniperus communis ssp. alpina, (two high peaks) or beech scrub (two small peaks) formed a mantle that could allow forest expansion. One high β-diversity peak referred to an anthropo-zoogenic boundary maintained by disturbance, without the presence of a mantle. A little peak indicated a gradual transition at the upper potential timberline limit where beech forest had lost its typical floristical composition and structural characteristics.

Structure and diversity trends (ß-diversity and species richness) across the Fagus sylvaticatimberline in the central Apennines were investigated. Twenty-three belt transects were laid out across the upper forest line in the Simbruini Mountains. Number of species, plant cover, and height of different layers were recorded in each quadrat. The moving split-window method was used to detect ecological discontinuities across beech timberlines. We show how ß-diversity changes along timberlines and we put forward some hypotheses about the possible dynamics of these transitions. Four models resulted from the analysis of ß-diversity trends: two ß-diversity peaks indicated a transition where shrubs, mainly Juniperus communisssp. alpina, (two high peaks) or beech scrub (two small peaks) formed a mantle that could allow forest expansion. One high ß-diversity peak referred to an anthropo-zoogenic boundary maintained by disturbance, without the presence of a mantle. A little peak indicated a gradual transition at the upper potential timberline limit where beech forest had lost its typical floristical composition and structural characteristics.

The degradation kinetics of untreated and rain-leached (wheat) straw have been investigated under isothermal conditions (500−650 K) in a weakly oxidative atmosphere. For both cases, weight loss curves follow a two reaction zone mechanism. In the first, fast volatile release results in about 20−70% solid conversion, followed by further slow solid devolatilization. A semiglobal kinetic mechanism is proposed and the kinetic constants are estimated for the two reaction zones and the formation of the volatile and the solid-phase product classes. For both cases, the activation energy of the first zone is higher than that of the second, but leaching significantly reduces the reaction rates at low temperatures for the first zone and high temperatures for the second zone.

Connectivity determines a large number of ecological functions of the landscape, including seed and animal dispersal, gene flow and disturbance propagation, and is therefore a key to understanding fluxes of matter and energy within land mosaics. Several approaches to quantifying landscape connectivity are possible. Among these, graph theory may be used to represent a landscape as a series of interconnected patches, where flows occur as a result of structural and/or functional patch connectivity. Within this context, we propose the use of a graph-theoretic index (i.e., the Harary index) as a measure of landscape connectivity. Results derived from the analysis of the vegetation map of Palmarola (central Italy) show that, from a statistical and ecological viewpoint, the Harary index may be a better measure of landscape connectivity than more traditional indices derived from transportation geography.

Radiative pyrolysis of thermally thick beech wood has been investigated through a comparison between dry and moist [11% dry basis (db)] particles, for heat fluxes in the range 27.5−80 kW/m². The initial moisture content has also been varied from 0 to 50% (db) for two radiative fluxes, 27.5 and 49 kW/m², corresponding to slow and fast external heat-transfer rates, as steady surface temperatures are about 625 and 800 K, respectively. For very slow heating, moisture evaporation precedes wood pyrolysis. As the external heating conditions are made more severe and/or the initial moisture content is increased, the two processes take place simultaneously, associated with the propagation of separate fronts along the particle radius. Spatial gradients also increase, while apparent weight loss kinetics from a single-peak rate turn into a two-peak rate. The conversion times increase almost linearly with the initial moisture content, but differences in primary product (char, gas, and liquids) yields and gas composition are negligible.

Two young males with limb-girdle muscular dystrophy (LGMD) resulting from sarcoglycan deficiency died at 27 (patient 1) and 18 years (patient 2) of severe cardiomyopathy. Genetic analysis showed that they were compound heterozygotes for mutations in the β sarcoglycan gene. One of these mutations, an 8 bp duplication in exon 3, was common to both patients. The second mutation in patient 2 was a 4 bp deletion at the splice donor site of intron 2, not reported previously. Patient 2 had more severe heart and skeletal muscle defects with faster deterioration; no sarcoglycans were detected in his skeletal muscle. The second mutation in patient 1, inferred because the unaffected father carries the 8 bp duplication, was not found. In patient 1, both heart and skeletal muscle were analysed and showed reduction of all sarcoglycans in both tissues and incorrect localisation of α and γ sarcoglycans in heart. Therefore mutations in one sarcoglycan gene can disrupt the entire sarcoglycan complex in both skeletal and cardiac muscle. Differing expression patterns of sarcoglycan components in heart and skeletal muscle could be the result of alternatively spliced transcripts in these tissues. By sequencing an alternative transcript, highly expressed in the heart and skeletal muscle of patient 1, we found an 87 bp cryptic exon not previously reported. Although cardiomyopathy can result from mutations in α and γ sarcoglycans, we show for the first time that the condition can also be caused by mutations in the β sarcoglycan gene. This report therefore expands the phenotype of sarcoglycanopathies and suggests that cardiac function in LGMD patients with defective sarcoglycan expression should be monitored.

The simultaneous analysis of spatial pattern in traditional phytosociological research is proposed. Groups of species with similar spatial distribution are identified and related to phytosociological syntaxa. Field data were obtained using the procedures of both approaches, namely phytosociological releves and belt transects. Multivariate analysis was used to examine the spatial patterns. The following phytosociological types (communities) were included in the syndynamic entity Orno-Querceto ilicis sigmetum: a) maquis of the Myrto-Lentiscetum association, b) communities of the Elaeoselino-Ampelodesmetum association in burned areas, usually found as a mosaic with c) therophyte communities (Crucianello-Hypocboeridetum association). Although these communities were homogeneous from the phytosociological point of view, on a detailed scale it was still possible to identify groups of species that tended to occur together and to exclude others. Species belonging to pioneer communities (Elaeoselino-Ampelodesmetum and Crucianello-Hypochoeridetum) were often in opposition to species of less disturbed communities (Myrto-Lentiscetum).

The pyrolysis characteristics of agricultural residues (wheat straw, olive husks, grape residues, and rice husks) and wood chips have been investigated on a bench scale. The experimental system establishes the conditions encountered by a thin (4 × 10^-2 m diameter) packed bed of biomass particles suddenly exposed in a high-temperature environment, simulated by a radiant furnace. Product yields (gases, liquids, and char) and gas composition, measured for surface bed temperatures in the range 650−1000 K, reproduce trends already observed for wood. However, differences are quantitatively large. Pyrolysis of agricultural residues is always associated with much higher solid yields (up to a factor of 2) and lower liquid yields. Differences are lower for the total gas, and approximate relationships exist among the ratios of the main gas species yields, indicating comparable activation energies for the corresponding apparent kinetics of formation. However, while the ratios are about the same for wood chips, rice husks, and straw, much lower values are shown by olive and grape residues. Large differences have also been found in the average values of the specific devolatilization rates. The fastest (up to factors of about 1.5 with respect to wood) have been observed for wheat straw and the slowest (up to factors of 2) for grape residues.

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 needed for large-scale applications.

Oxidative degradation and ignition of straw and rain-leached straw were investigated at a laboratory scale. Leaching reduced the ash content (by about 50wt.%), in particular chlorine and potassium, and caused some swelling. A loose-packed bed (density 50kg/m3) was exposed to a forced flow (velocities in the range 0.34–1.9m/s) of hot air (temperatures in the range 540–890K). Degradation rates became significant for bed temperatures of about 500K. However, the ignition temperatures were only slightly higher, hence oxidative degradation is a slow process, resulting in maximum conversions of about 50wt.% (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.

This study is a comparison of the spontaneous vascular flora of five Italian cities: Milan, Ancona, Rome, Cagliari and Palermo. The aims of the study are to test the hypothesis that urbanization results in uniformity of urban floras, and to evaluate the role of alien species in the flora of settlements located in different phytoclimatic regions. To obtain comparable data, ten plots of 1 ha, each representing typical urban habitats, were analysed in each city. The results indicate a low floristic similarity between the cities, while the strongest similarity appears within each city and between each city and the seminatural vegetation of the surrounding region. In the Mediterranean settlements, even the most urbanized plots reflect the characters of the surrounding landscape and are rich in native species, while aliens are relatively few. These results differ from the reported uniformity and the high proportion of aliens which generally characterize urban floras elsewhere. To explain this trend the importance of apophytes (indigenous plants expanding into man‐made habitats) is highlighted; several Mediterranean species adapted to disturbance (i.e. grazing, trampling, and human activities) are pre‐adapted to the urban environment. In addition, consideration is given to the minor role played by the ‘urban heat island’ in the Mediterranean basin, and to the structure and history of several Italian settlements, where ancient walls, ruins and archaeological sites in the periphery as well as in the historical centres act as conservative habitats and provide connection with seed‐sources on the outskirts.

TEM, THEED and field-assisted silver ion exchange have been employed to study the glow discharge (GD) Si:H:Cl films deposited from SiH4-SiCl4 gas mixtures. The character of the THEED patterns shows that the films are rather amorphous, and that their structure does not alter with the change in the gas mixture. The honeycomb-like morphology of the films is strongly affected by the type of gas in which SiH4 is diluted (Ar or H2). An increase in the SiCl4 partial pressure leads to the uniformity and to the decrease of the island dimension only for the films deposited from SiH4(H2)-SiCl4. A possible correlation between the film morphology and the micropore density is proposed.

Lo studio e basato sul confronto tra la flora di 5 citta localizzate nelle principali regioni fitoclimatiche italiane: Milano, Ancona, Roma, Cagliari e Palermo. L'analisi di 684 specie rilevate in 50 aree campione ha evidenziato l'importanza delle apofite nella flora urbana in Italia e il ruolo delle terofite che provengono direttamente dalla vegetazione mediterranea. Il confronto ha inoltre mostrato la dominanza dei fattori biogeografici nella costituzione della copertura vegetale delle 5 citta. Questi risultati contrastano con l'elevata percentuale di specie esotiche e con l'uniformita floristica osservate nelle aree urbane dell'Europa Centrale.