How adaptable is the hydraulic system of European beech in the face of climate change-related precipitation reduction?

Climate warming will increase the drought exposure of many forests world-wide. It is not well understood how trees adapt their hydraulic architecture to a long-term decrease in water availability. We examined 23 traits characterizing the hydraulic architecture and growth rate of branches and the dependent foliage of mature European beech (Fagus sylvatica) trees along a precipitation gradient (855-594 mm yr(-1) ) on uniform soil. A main goal was to identify traits that are associated with xylem efficiency, safety and growth. Our data demonstrate for the first time a linear increase in embolism resistance with climatic aridity (by 10%) across populations within a species. Simultaneously, vessel diameter declined by 7% and pit membrane thickness (Tm ) increased by 15%. Although specific conductivity did not change, leaf-specific conductivity declined by 40% with decreasing precipitation. Of eight plant traits commonly associated with embolism resistance, only vessel density in combination with pathway redundancy and Tm were related. We did not confirm the widely assumed trade-off between xylem safety and efficiency but obtained evidence in support of a positive relationship between hydraulic efficiency and growth. We conclude that the branch hydraulic system of beech has a distinct adaptive potential to respond to a precipitation reduction as a result of the environmental control of embolism resistance.

Biocomposites from waste derived biochars: Mechanical, thermal, chemical, and morphological properties

To identify a route for organic wastes utilisation, biochar made from various feedstocks (landfill pine saw dust, sewage sludge, and poultry litter) and at diverse pyrolysis conditions, were collected. These biochars were used to fabricate wood and polypropylene biocomposites with a loading level of 24 mass%. The composites were tested for their mechanical, chemical, thermal, morphological, and fire properties. The poultry litter biochar biocomposite, with highest ash content, was found to have high values of tensile/flexural strength, tensile/flexural modulus, and impact strength, compared to other composites. In general, addition of all the biochars enhanced the tensile/flexural moduli of the composites. The crystal structure of polypropylene in the composite was intact after the incorporation of all the biochars. The final chemical and crystal structure of the composite were an additive function of the individual components. The biochar particles along with wood acted as nucleating agents for the recrystallization of polypropylene in composite. Each component in the composites was found to decompose individually under thermal regime. The electron microscopy revealed the infiltration of polypropylene into the biochar pores and a general good dispersion in most composites. The poultry litter composite was found to have lower heat release rate under combustion regime.

Adsorption of methylene blue on biochar microparticles derived from different waste materials

Biochar microparticles were prepared from three different types of biochar, derived from waste materials, such as pine wood (BC-PW), pig manure (BC-PM) and cardboard (BC-PD) under various pyrolysis conditions. The microparticles were prepared by dry grinding and sequential sieving through various ASTM sieves. Particle size and specific surface area were analyzed using laser particle size analyzer. The particles were further characterized using scanning electron microscope (SEM). The adsorption capacity of each class of adsorbent was determined by methylene blue adsorption tests in comparison with commercially available activated carbon. Experimental results showed that dye adsorption increased with initial concentration of the adsorbate and biochar dosage. Biochar microparticles prepared from different sources exhibited improvement in adsorption capacity (7.8±0.5 mg g(-1) to 25±1.3 mg g(-1)) in comparison with raw biochar and commercially available activated carbon. The adsorption capacity varied with source material and method of production of biochar. The maximum adsorption capacity was 25 mg g(-1) for BC-PM microparticles at 25°C for an adsorbate concentration of 500 mg L(-1) in comparison with 48.30±3.6 mg g(-1) for activated carbon. The equilibrium adsorption data were best described by Langmuir model for BC-PM and BC-PD and Freundlich model for BC-PW.

Assessment of chemical and material contamination in waste wood fuels--A case study ranging over nine years

The increased demand for waste wood (WW) as fuel in Swedish co-combustion facilities during the last years has increased the import of this material. Each country has different laws governing the use of chemicals and therefore the composition of the fuel will likely change when combining WW from different origins. To cope with this, enhanced knowledge is needed on WW composition and the performance of pre-treatment techniques for reduction of its contaminants. In this study, the chemical and physical characteristics of 500 WW samples collected at a co-combustion facility in Sweden between 2004 and 2013 were investigated to determine the variation of contaminant content over time. Multivariate data analysis was used for the interpretation of the data. The concentrations of all the studied contaminants varied widely between sampling occasions, demonstrating the highly variable composition of WW fuels. The efficiency of sieving as a pre-treatment measure to reduce the levels of contaminants was not sufficient, revealing that sieving should be used in combination with other pre-treatment methods. The results from this case study provide knowledge on waste wood composition that may benefit its management. This knowledge can be applied for selection of the most suitable pre-treatments to obtain high quality sustainable WW fuels.

Exposure of wood in floodplains affects its chemical quality and its subsequent breakdown in streams

In stream ecosystems, coarse organic matter from the riparian vegetation, a key food resource, is often retained in the floodplains before reaching the channel. During floodplain exposure, organic matter can be affected by abiotic and biotic processes ("preconditioning"), which alter its quality and affect its subsequent decomposition in streams. We analyzed the effect of floodplain preconditioning on wood quality (lignin, C, N, P, K, among others), and its subsequent aquatic breakdown, paying special attention to microbial activity. We simulated preconditioned standard wooden sticks on one arid stream floodplain for 3 and 4 months, and then monitored their breakdown in three different streams, together with control (non-preconditioned) sticks. Preconditioning reduced lignin mass and C:N and lignin:N ratios, caused the leaching of soluble nutrients such as P and K, as well as N immobilization by microbes. These changes enhanced the breakdown of wood in the first week of immersion, but had no effect on breakdown rates after 4 months of incubation in the streams, although N immobilization was diminished. Our results suggest that terrestrial preconditioning could alter the role of wood as a long-lasting nutrients and energy source for freshwater ecosystem.

Modeling the influence of alternative forest management scenarios on wood production and carbon storage: A case study in the Mediterranean region

Forest ecosystems are fundamental for the terrestrial biosphere as they deliver multiple essential ecosystem services (ES). In environmental management, understanding ES distribution and interactions and assessing the economic value of forest ES represent future challenges. In this study, we developed a spatially explicit method based on a multi-scale approach (MiMoSe-Multiscale Mapping of ecoSystem services) to assess the current and future potential of a given forest area to provide ES. To do this we modified and improved the InVEST model in order to adapt input data and simulations to the context of Mediterranean forest ecosystems. Specifically, we integrated a GIS-based model, scenario model, and economic valuation to investigate two ES (wood production and carbon sequestration) and their trade-offs in a test area located in Molise region (Central Italy). Spatial information and trade-off analyses were used to assess the influence of alternative forest management scenarios on investigated services. Scenario A was designed to describe the current Business as Usual approach. Two alternative scenarios were designed to describe management approaches oriented towards nature protection (scenario B) or wood production (scenario C) and compared to scenario A. Management scenarios were simulated at the scale of forest management units over a 20-year time period. Our results show that forest management influenced ES provision and associated benefits at the regional scale. In the test area, the Total Ecosystem Services Value of the investigated ES increases 85% in scenario B and decreases 82% in scenario C, when compared to scenario A. Our study contributes to the ongoing debate about trade-offs and synergies between carbon sequestration and wood production benefits associated with socio-ecological systems. The MiMoSe approach can be replicated in other contexts with similar characteristics, thus providing a useful basis for the projection of benefits from forest ecosystems over the future.

Cardboard/sawdust briquettes as biomass fuel: Physical-mechanical and thermal characteristics

This paper elaborates experimental analysis of cardboard/sawdust briquettes as a viable option for biomass fuel. Physical-mechanical and thermal characteristics of cardboard/sawdust briquettes were investigated. The influence of the main parameters on heating content was also examined through an ANOVA and regression analysis, i.e. pressure influence (that was applied in a punch-and-die process), cardboard/sawdust ratio influence and finally drying temperature influence. In order to find the maximum heating value, minimum ash content and maximum compressive strength optimization were done. The optimal values obtained for the studied briquetting process parameters are a compression force of 588.6 kN, a sawdust mass of 46.66% and a drying temperature of 22°C. According to the mathematical model obtained, these optimal values give a maximum higher heating value of 17.41 MJ/kg, a minimum ash content of 6.62% and a maximum compressive strength of 149.54 N/mm. Finally, Cardboard/sawdust briquettes showed potential for application as viable biomass fuel.

Quantification of obeche wood allergen: Development of a sensitive sandwich-ELISA for occupational exposure assessment

Obeche wood is a prominent cause of allergic occupational asthma. To reduce the risk of immunoglobulin E (IgE)-mediated sensitization it is important to assess airborne obeche wood allergen concentrations at exposed workplaces. Therefore, a highly sensitive obeche wood allergen immunoassay was developed and applicability was proven on airborne passive dust samples in Spanish wood workshops. Obeche wood sandwich enzyme-linked immunosorbent assay (ELISA) polyclonal antibodies (pAbs) were developed. Test specificity was verified by different wood and mold extracts. Obeche wood allergen monitoring was conducted in four Spanish wood workshops, including wood-dust-exposed and nonexposed areas inside and outside the workplaces, as well as controls. Dust was collected with electrostatic dust collectors (EDC). Measuring range of the obeche wood sandwich-ELISA was between 36 pg/ml and 1.6 µg/ml. The test system showed only marginal reactivity to other hardwoods and no reactivity to softwoods and molds. Obeche allergen was detected in all EDC from workplaces. The highest concentration was measured in the workshop with the longest obeche wood exposure (geometric mean [GM]: 7548 µg/m²); shorter obeche wood processing periods resulted in lower amounts of allergen (GM: 29 µg/m²). Obeche wood allergen transfer from exposed workplaces to nonexposed areas inside and outside the workshop was assessed. In control EDC from nonexposed facilities/homes no obeche wood allergen was found. The new obeche wood sandwich-ELISA is a valid tool to quantify obeche allergen exposure. Evidence indicates it will be possible to monitor obeche allergen exposure during different processes, as well as transfer effects in nonexposed areas.

Substitution potentials of recycled HDPE and wood particles from post-consumer packaging waste in Wood-Plastic Composites

The market share of Wood-Plastic Composites (WPC) is small but expected to grow sharply in Europe. This raises some concerns about suitable wood particles needed in the wood-based panels industry in Europe. Concerns are stimulated by the competition between the promotion of wooden products through the European Bioeconomy Strategy and wood as an energy carrier through the Renewable Energy Directive. Cascade use of resources and valorisation of waste are potential strategies to overcome resource scarcity. Under experimental design conditions, WPC made from post-consumer recycled wood and plastic (HDPE) were compared to WPC made from virgin resources. Wood content in the polymer matrix was raised in two steps from 0% to 30% and 60%. Mechanical and physical properties and colour differences were characterized. The feasibility of using cascaded resources for WPC is discussed. Results indicate the technical and economic feasibility of using recycled HDPE from packaging waste for WPC. Based on technical properties, 30% recycled wood content for WPC is feasible, but economic and political barriers of efficient cascading of biomass need to be overcome.

Influence of nitrogen sources on the enzymatic activity and grown by Lentinula edodes in biomass Eucalyptus benthamii

Lignocellulose is the most abundant environmental component and a renewable organic resource in soil. There are some filamentous fungi which developed the ability to break down and use cellulose, hemicellulose and lignin as an energy source. The objective of this research was to analyze the effect of three nitrogen resources (ammonium sulfate, saltpetre, soybean) in the holocellulolitic activity of Lentinula edodes EF 50 using as substrate sawdust E. benthamii. An experimental design mixture was applied with repetition in the central point consisting of seven treatments (T) of equal concentrations of nitrogen in ammonium sulfate, potassium nitrate and soybean. The enzymatic activity of avicelase, carboxymetilcellulase, β-glucosidase, xylanases and manganese peroxidase was determined. The humidity, pH, water activity (aw) and qualitative analysis of mycelial growth in 8 times of cultivation were evaluated. The results showed negative effect on enzyme production in treatments with maximum concentration of ammonium sulfate and potassium nitrate. The treatments with cooked soybean flour expressed higher enzymatic activities in times of 3, 6 and 9 days of culture, except in the activity of manganese peroxidase. The highest production was observed in the treatment with ammonium sulfate, and soybean (83.86 UI.L-1) at 20 days of cultivation.

Distribution and leaching characteristics of trace elements in ashes as a function of different waste fuels and incineration technologies

Impact of waste fuels (virgin/waste wood, mixed biofuel (peat, bark, wood chips) industrial, household, mixed waste fuel) and incineration technologies on partitioning and leaching behavior of trace elements has been investigated. Study included 4 grate fired and 9 fluidized boilers. Results showed that mixed waste incineration mostly caused increased transfer of trace elements to fly ash; particularly Pb/Zn. Waste wood incineration showed higher transfer of Cr, As and Zn to fly ash as compared to virgin wood. The possible reasons could be high input of trace element in waste fuel/change in volatilization behavior due to addition of certain waste fractions. The concentration of Cd and Zn increased in fly ash with incineration temperature. Total concentration in ashes decreased in order of Zn>Cu>Pb>Cr>Sb>As>Mo. The concentration levels of trace elements were mostly higher in fluidized boilers fly ashes as compared to grate boilers (especially for biofuel incineration). It might be attributed to high combustion efficiency due to pre-treatment of waste in fluidized boilers. Leaching results indicated that water soluble forms of elements in ashes were low with few exceptions. Concentration levels in ash and ash matrix properties (association of elements on ash particles) are crucial parameters affecting leaching. Leached amounts of Pb, Zn and Cr in >50% of fly ashes exceeded regulatory limit for disposal. 87% of chlorine in fly ashes washed out with water at the liquid to solid ratio 10 indicating excessive presence of alkali metal chlorides/alkaline earths.

Roofing Materials Assessment: Investigation of Five Metals in Runoff from Roofing Materials

To assess the contribution of five toxic metals from new roofing materials to stormwater, runoff was collected from 14 types of roofing materials and controls during 20 rain events and analyzed for metals. Many of the new roofing materials evaluated did not show elevated metals concentrations in the runoff. Runoff from several other roofing materials was significantly higher than the controls for arsenic, copper, and zinc. Notably, treated wood shakes released arsenic and copper, copper roofing released copper, PVC roofing released arsenic, and Zincalume® and EPDM roofing released zinc. For the runoff from some of the roofing materials, metals concentrations decreased significantly over an approximately one-year period of aging. Metals concentrations in runoff were demonstrated to depend on a number of factors, such as roofing materials, age of the materials, and climatic conditions. Thus, application of runoff concentrations from roofing materials to estimate basin-wide releases should be undertaken cautiously.

Techno-economic analysis of CHP system supplied by waste forest biomass

Poland, as for Europe, is a country with an average forest cover of approximately 30%. In these forests, more than 37M m3 of wood, mostly coniferous (over 80%), is harvested per year. In 2012, 4.2M m3 of sawn timber was produced (sawn timber without factory lumber). At the same time, in Poland there are over 8000 sawmills, whereas only about 700 of them saw over 90% of the harvested timber. So much fragmentation is a major cause of low sawmills innovation, particularly of those small ones. However, in recent years, a trend of development in this sector is noticeable, and it is through rationalisation of material and energy economy. One of the methods to increase the technical and economic effectiveness of enterprises involved in woodworking is to build in the combined heat and power system (CHP) plant with the ORC system into the existing infrastructure, which will be matched to the needs of the company. This article presents an analysis of the profitability of the investment based on the example of a medium-sized company sawing approximately 50,000 m3 of timber per year, and the economic analysis was performed for prices and costs valid in Poland. The analysis made for the 1650 kW(el) organic Rankine cycle (ORC) system, has resulted in a profitability index PI = 1.3, on the assumptions that the ORC system operates for 6000 h y(-1), will be purchased at the price of 4500 € kW(el)(-1) and at the price of electricity sales of 130 € MWh(-1).

δ²H, δ¹³C and δ¹⁸O from whole wood, α-cellulose and lignin methoxyl groups in Pinus sylvestris: a multi-parameter approach

Novel tree ring parameters - δ(13)C and δ(2)H from methoxyl groups - have been developed to reconstruct palaeoclimate. Tests with δ(13)C and δ(18)O derived from whole wood and cellulose samples, however, indicated differences in the isotopic composition and climate signal, depending on the extracted wood component. We assess this signal dependency by analysing (i) δ(13)C and δ(18)O from whole wood and cellulose and (ii) δ(13)C and δ(2)H from methoxyl groups, using Pinus sylvestris L. growing near Altenkirchen (Germany). Results indicate significant correlations among the time series derived from whole wood, cellulose, and lignin methoxyl groups. Compared with the whole wood samples, δ(13)C from methoxyl groups showed a different and overall lower response to climate parameters. On the other hand, δ(2)H from methoxyl groups showed high correlations with temperature and was also correlated with ring width, indicating its potential as a temperature proxy. Isotope time series with the highest correlation with climatic parameter were: (i) whole wood and cellulose δ(13)C with growing season precipitation and summer temperature; (ii) methoxyl groups with spring precipitation; (iii) whole wood and cellulose δ(18)O correlates with annual evapotranspiration and water balance; and (iv) methoxyl group δ(2)H with spring temperatures. These findings reveal that multiple climate elements can be reconstructed from different wood components and that whole wood proxies perform comparably to cellulose time series.

The decay of wood in landfills in contrasting climates in Australia

Wood products in landfill are commonly assumed to decay within several decades, returning the carbon contained therein to the atmosphere, with about half the carbon released as methane. However, the rate and extent of decay is not well known, as very few studies have examined the decay of wood products in landfills. This study reports on the findings from landfill excavations conducted in the Australian cities of Sydney and Cairns located in temperate and tropical environments, respectively. The objective of this study was to determine whether burial of the wood in warmer, more tropical conditions in Cairns would result in greater levels of decay than occurs in the temperate environment of Sydney. Wood samples recovered after 16-44years in landfill were examined through physical, chemical and microscopic analyses, and compared with control samples to determine the carbon loss. There was typically little or no decay in the wood samples analysed from the landfill in Sydney. Although there was significant decay in rainforest wood species excavated from Cairns, decay levels for wood types that were common to both Cairns and Sydney landfills were similar. The current Intergovernmental Panel on Climate Change (IPCC, 2006) default decay factor for organic materials in landfills is 50%. In contrast, the carbon loss determined for Pinus radiata recovered from Sydney and Cairns landfills was 7.9% and 4.4%, respectively, and 0% for Agathis sp. This suggests that climate did not influence decay, and that the more extensive levels of decay observed for some wood samples from Cairns indicates that those wood types were more susceptible to biodegradation. Microscopic analyses revealed that most decay patterns observed in samples analysed from Sydney were consistent with aerobic fungal decay. Only a minor portion of the microbial decay was due to erosion bacteria active in anaerobic/near anaerobic environments. The findings of this study strongly suggest that models that adopt current accepted default factors for the decay of wood in landfills greatly overestimate methane emissions.

Effect of turning frequency and season on composting materials from swine high-rise facilities

Composting swine slurries has several advantages, liquid slurries are converted to solids at lower moisture, the total volume and weight of material is reduced and the stabilized product is more easily transported off-site. Despite this, swine waste is generally stored, treated and applied in its liquid form. High-rise finishing facilities (HRFF) permit liquid slurries to be converted to solids which are partially decomposed underneath the HRFF and then finished in compost windrows. The purpose of this study was to evaluate the effect of turning frequency and ambient weather conditions on biological, physical and chemical properties of composted slurry-woodchip mixtures from HRFF. Compost trials were conducted in either fall (FT) or spring (ST) and piles were turned once or three times per week or upon compost temperature reaching 65°C. Physical, chemical and microbiological characteristics were measured over the course of 112 (FT) or 143 (ST) days of composting. Total carbon, total nitrogen (N) and inorganic N decreased in all piles. Ammonium decreased while nitrate increased in all piles (including unturned), but total N losses were greatest in piles turned more frequently during the ST. Microbial populations of nitrifiers were dominated by ammonia-oxidizing archaea (3.0×10(3)-4.2×10(6)cellsg(-1) compost) but ammonia oxidizing bacteria (below detection to 6.0×10(5)cellsg(-1) compost) varied in response to turning and compost temperature; denitrifiers were present in high concentrations throughout the process. Swine HRFF materials composted well in windrows regardless of turning frequency and despite significant differences in starting materials and low initial C/N. Volume reduction, low moisture and low readily degradable organic matter suggest that the finished compost would have lower transportation costs and should provide value as a soil conditioner.

Chemical composition and physical properties of filter fly ashes from eight grate-fired biomass combustion plants

For the handling, treatment and utilization of fly ash from biomass combustion its chemical composition and physical properties are important. In this study eight filter fly ashes from different grate-fired biomass combustion plants were investigated. In fly ash from straw combustion high concentrations of (K) were found, whereas in the fly ash from wood combustion the concentrations of Ca and Mg were higher. The average concentration of PO4(3-) was similar in both types of fly ashes. In all wood fly ashes some measured heavy metal concentrations were above the limits for utilization. The straw fly ashes were much less contaminated and can be utilized. For wood fly ash most parameters showed little variation, except from one fly ash where the dust pre-separator is in poor condition. The average values were: mass median diameter 4.3±0.8 μm, spread of particle size distribution 19±11, particle density 2620±80 kg/m3 and angle of repose 50°±1°. The density of the straw fly ashes is lower (2260±80 kg/m3) and the spread of the size distribution is higher (72±24). For one straw combustion fly ash the values of the mass median diameter and the angle of repose were similar to the values of wood combustion fly ash, for the other straw fly ash the values differed considerably. While the particle size of this fly ash was much smaller, surprisingly the angle of repose was also lower. This can be attributed to the formation of small agglomerates in this fly ash, which were not disintegrated without a certain stress.

LCA-based optimization of wood utilization under special consideration of a cascading use of wood

Cascading, the use of the same unit of a resource in multiple successional applications, is considered as a viable means to improve the efficiency of resource utilization and to decrease environmental impacts. Wood, as a regrowing but nevertheless limited and increasingly in demand resource, can be used in cascades, thereby increasing the potential efficiency per unit of wood. This study aims to assess the influence of cascading wood utilization on optimizing the overall environmental impact of wood utilization. By combining a material flow model of existing wood applications - both for materials provision and energy production - with an algebraic optimization tool, the effects of the use of wood in cascades can be modelled and quantified based on life cycle impact assessment results for all production processes. To identify the most efficient wood allocation, the effects of a potential substitution of non-wood products were taken into account in a part of the model runs. The considered environmental indicators were global warming potential, particulate matter formation, land occupation and an aggregated single score indicator. We found that optimizing either the overall global warming potential or the value of the single score indicator of the system leads to a simultaneous relative decrease of all other considered environmental impacts. The relative differences between the impacts of the model run with and without the possibility of a cascading use of wood were 7% for global warming potential and the single score indicator, despite cascading only influencing a small part of the overall system, namely wood panel production. Cascading led to savings of up to 14% of the annual primary wood supply of the study area. We conclude that cascading can improve the overall performance of a wood utilization system.

Co-composting of rose oil processing waste with caged layer manure and straw or sawdust: effects of carbon source and C/N ratio on decomposition

Rose oil is a specific essential oil that is produced mainly for the cosmetics industry in a few selected locations around the world. Rose oil production is a water distillation process from petals of Rosa damascena Mill. Since the oil content of the rose petals of this variety is between 0.3-0.4% (w/w), almost 4000 to 3000 kg of rose petals are needed to produce 1 kg of rose oil. Rose oil production is a seasonal activity and takes place during the relatively short period where the roses are blooming. As a result, large quantities of solid waste are produced over a limited time interval. This research aims: (i) to determine the possibilities of aerobic co-composting as a waste management option for rose oil processing waste with caged layer manure; (ii) to identify effects of different carbon sources - straw or sawdust on co-composting of rose oil processing waste and caged layer manure, which are both readily available in Isparta, where significant rose oil production also takes place; (iii) to determine the effects of different C/N ratios on co-composting by the means of organic matter decomposition and dry matter loss. Composting experiments were carried out by 12 identical laboratory-scale composting reactors (60 L) simultaneously. The results of the study showed that the best results were obtained with a mixture consisting of 50% rose oil processing waste, 64% caged layer manure and 15% straw wet weight in terms of organic matter loss (66%) and dry matter loss (38%).

A novel approach in organic waste utilization through biochar addition in wood/polypropylene composites

In an attempt to concurrently address the issues related to landfill gas emission and utilization of organic wastes, a relatively novel idea is introduced to develop biocomposites where biochar made from pyrolysis of waste wood (Pinus radiata) is added with the same wood, plastic/polymer (polypropylene) and maleated anhydride polypropylene (MAPP). Experiments were conducted by manufacturing wood and polypropylene composites (WPCs) mixed with 6 wt%, 12 wt%, 18 wt%, 24 wt%, and 30 wt% biochar. Though 6 wt% addition had similar properties to that of the control (composite without biochar), increasing biochar content to 24 wt% improved the composite's tensile/flexural strengths and moduli. The biochar, having high surface area due to fine particles and being highly carbonised, acted as reinforcing filler in the biocomposite. Composites having 12 wt% and 18 wt% of biochar were found to be the most ductile and thermally stable, respectively. This study demonstrates that, WPCs added with biochar has good potential to mitigate wastes while simultaneously producing biocomposites having properties that might be suited for various end applications.

Aryl hydrocarbon receptor activation and developmental toxicity in zebrafish in response to soil extracts containing unsubstituted and oxygenated PAHs

Many industrial sites are polluted by complex mixtures of polycyclic aromatic compounds (PACs). Besides polycyclic aromatic hydrocarbons (PAHs), these mixtures often contain significant amounts of more polar PACs including oxygenated PAHs (oxy-PAHs). The effects of oxy-PAHs are, however, poorly known. Here we used zebrafish embryos to examine toxicities and transcriptional changes induced by PAC containing soil extracts from three different industrial sites: a gasworks (GAS), a former wood preservation site (WOOD), and a coke oven (COKE), and to PAH and oxy-PAH containing fractions of these. All extracts induced aryl hydrocarbon receptor (Ahr)-regulated mRNAs, malformations, and mortality. The WOOD extract was most toxic and the GAS extract least toxic. The extracts induced glutathione transferases and heat shock protein 70, suggesting that the toxicity also involved oxidative stress. With all extracts, Ahr2-knock-down reduced the toxicity, indicating a significant Ahr2-dependence on the effects. Ahr2-knock-down was most effective with the PAH fraction of the WOOD extract and with the oxy-PAH fraction of the COKE extract. Our results indicate that oxy-PAH containing mixtures can be as potent Ahr activators and developmental toxicants as PAHs. In addition to Ahr activating potency, the profile of cytochrome P4501 inhibitors may also determine the toxic potency of the extracts.

Edge effects on moisture reduce wood decomposition rate in a temperate forest

Forests around the world are increasingly fragmented, and edge effects on forest microclimates have the potential to affect ecosystem functions such as carbon and nutrient cycling. Edges tend to be drier and warmer due to the effects of insolation, wind, and evapotranspiration and these gradients can penetrate hundreds of metres into the forest. Litter decomposition is a key component of the carbon cycle, which is largely controlled by saprotrophic fungi that respond to variation in temperature and moisture. However, the impact of forest fragmentation on litter decay is poorly understood. Here, we investigate edge effects on the decay of wood in a temperate forest using an experimental approach, whereby mass loss in wood blocks placed along 100 m transects from the forest edge to core was monitored over 2 years. Decomposition rate increased with distance from the edge, and was correlated with increasing humidity and moisture content of the decaying wood, such that the decay constant at 100 m was nearly twice that at the edge. Mean air temperature decreased slightly with distance from the edge. The variation in decay constant due to edge effects was larger than that expected from any reasonable estimates of climatic variation, based on a published regional model. We modelled the influence of edge effects on the decay constant at the landscape scale using functions for forest area within different distances from edge across the UK. We found that taking edge effects into account would decrease the decay rate by nearly one quarter, compared with estimates that assumed no edge effect.

Fragmentation of protonated 2-(2-phenylethyl)chromones from agarwood: the diagnostic role of ion/neutral complexes as reactive intermediates

A positive-ion electrospray ionisation collision-induced dissociation mass spectrometric study on the fragmentation of the [M + H](+) ions of 2-(2-phenylethyl)chromone and a set of nine hydroxyl- and/or methoxy-substituted derivatives has revealed a highly prominent fragmentation channel, the loss of benzoquinomethanes or a benzaldehyde, respectively, as a diagnostic feature for 2-(2-phenylethyl)chromones that bear a hydroxyl group at the para- (4'-), ortho- (2'-) and/or benzylic (α-) position of the phenylethyl residue. Derivatives that bear only a meta- (3'-) hydroxyl group do not undergo this elimination. The intermediacy of ion/neutral complexes (INCs) is invoked to explain this fragmentation, which involves the remarkable intra-complex proton or hydrogen atom transfer from the remote 4'-OH (or the 2'- or α-OH) functionalities. Density functional theory (B3LYP/6-31G(d)) calculations confirm the energetic preference for these elimination channels and agree with the limited thermochemical data known for para- and ortho- benzoquinomethanes. The INC-mediated losses of the benzaldehydes from the [M + H](+) ions of the α-hydroxy-substituted 2-(2-phenylethyl)chromones correspond to a particularly facile (vinylogous) Grob fragmentation. The study may be viewed as a telling example of the diagnostic role of ion/neutral complexes as intermediates for the structural assignment of constitutional isomers by mass spectrometry.

Quality improvement of pyrolysis oil from waste rubber by adding sawdust

This work was aimed at improving the pyrolysis oil quality of waste rubber by adding larch sawdust. Using a 1 kg/h stainless pyrolysis reactor, the contents of sawdust in rubber were gradually increased from 0%, 50%, 100% and 200% (wt%) during the pyrolysis process. Using a thermo-gravimetric (TG) analyzer coupled with Fourier transform infrared (FTIR) analysis of evolving products (TG-FTIR), the weight loss characteristics of the heat under different mixtures of sawdust/rubber were observed. Using the pyrolysis-gas chromatography (GC)-mass spectrometry (Py-GC/MS), the vapors from the pyrolysis processes were collected and the compositions of the vapors were examined. During the pyrolysis process, the recovery of the pyrolysis gas and its composition were measured in-situ at a reaction temperature of 450 °C and a retaining time of 1.2s. The results indicated that the efficiency of pyrolysis was increased and the residual carbon was reduced as the percentage of sawdust increased. The adding of sawdust significantly improved the pyrolysis oil quality by reducing the polycyclic aromatic hydrocarbons (PAHs) and nitrogen and sulfur compounds contents, resulting in an improvement in the combustion efficiency of the pyrolysis oil.

Experimental and predicted approaches for biomass gasification with enriched air-steam in a fluidised bed

Thermo-chemical gasification of sawdust refuse-derived fuel was performed on a bench-scale fluidised bed gasifier with enriched air and steam as fluidising and oxidising agents. Dolomite as a natural mineral catalyst was used as bed material to reform tars and hydrocarbons. A series of experiments were carried out under typical operating conditions for gasification, as reported in the article. A modified equilibrium model, based on equilibrium constants, was developed to predict the gasification process. The sensitivity analysis of operating parameters, such as the fluidisation velocity, oxygen percentage of the enriched air and steam to biomass ratios on the produced gas composition, lower heating value, carbon conversion and cold gas efficiency was investigated. The results showed that the predicted syngas composition was in better agreement with the experimental data compared with the original equilibrium model. The higher fluidisation velocity enhanced gas-solid mixing, heat and mass transfers, and carbon fines elutriation, simultaneously. With the increase of oxygen percentage from 21% to 45%, the lower heating value of syngas increased from 5.52 MJ m(-3) to 7.75 MJ m(-3) and cold gas efficiency from 49.09% to 61.39%. The introduction of steam improved gas quality, but a higher steam to biomass ratio could decrease carbon conversion and gasification efficiency owing to a low steam temperature. The optimal value of steam to biomass ratio in this work was 1.0.