196 research outputs found
Microwave characterization of polymer composite based on Biochar: A comparison of composite behaviour for Biochar and MWCNTs
In this work, Biochar is used as a filler in Epoxy resin for composite preparation. The electrical characteristics of composites are analyzed in function of different filler percentages. Results obtained are compared with composites based on multi-wall carbon nanotubes
Arbuscular mycorrhizal colonization in black poplar roots after defoliation by a non-native and a native insect
A major goal in ecology is to understand how interactions among organisms influence ecosystem services. This work compares the effects of two Lepidoptera defoliators, one non-native (Hyphantria cunea) and one native (Lymantria dispar) to Europe, on the colonization of black poplar (the Populus nigra clone "Jean Pourtet") roots by an arbuscular mycorrhizal (AM) symbiotic fungus (Funneliformis mosseae) in a pot experiment. The effects of defoliation have also been assessed on the expression of fungal and plant genes playing a role during symbiosis. Both control and defoliated poplars have shown a low level of mycorrhization. Additionally, neither the non-native nor the native insect seem to strongly affect the AM colonization, at least at the time of observation (eight days from the end of the defoliation). Concerning the gene expression analysis, our results suggest that defoliation does not influence neither the expression of genes coding for a fungal and a plant phosphate transporter nor that of a gene coding for a fungal ATPase, and that there were no differences between defoliation carried out by the non-native and the native insect. \ua9 SISEF
Mechanical properties of epoxy/multi-walled carbon nanotubes composites
In this paper, two types of multi-wall carbon nanotubes (MWCNTs) were dispersed into two different epoxy resins b high - shear mixing. Dispersion and homogenisation of nanofillers was analysed by Field Emission Scanning Electron Microscopy (FESEM). Microhardness of epoxy/MWCNTs nanocomposites, as well as of neat epoxy resins, is measure by Vickers method. The evolution of nanocomposites microhardness values were studied in function of curing time takin in account the influence of two different epoxy matrix and MWCNTs. Asymptotic values were analysed and compare with those of pure epoxy resin
Development of a simplified analytical model for a passive inertial system solicited by wave motion
This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordThis paper presents a theoretical and experimental investigation about the modelling of a 1:45 scale prototype Wave Energy Converter (WEC). An analytical model is implemented to describe its behaviour in a wave tank. The aim is to provide a contribution to modelling tools used for WEC characterisation and design. Hydrodynamic characterisation software is avoided in favour of a simpler and more versatile design tool destined to a wider range of users. Therefore, an alternative approach is presented, based on mechanical analogies and the use of Matlab/Simulink/SimMechanics environment. This analytical model was constructed using linear wave theory, coupled with a non-linear model for the device and its power take-off system (PTO). Assumptions on incident waves and geometric properties of the device were required and implemented on the basis of literature of naval architecture, ships stabilization and control issues. Simulation results were compared and validated with those obtained in the same range of experimental tests of the prototype in wave tank. Trends and values of both investigation techniques show a good agreement, indicating the validity of the methodology adopted and leaving space for future improvements of the same. Finally, as example of application, the model was applied in a show case in order to estimate the energy yield by the WEC if scaled to real size, using Froude scaling. Results are encouraging and show the viability of the proposed design
Life Cycle Assessment (LCA): New poplar clones allow an environmentally sustainable cultivation
In Italy 72 poplar clones ( Populus spp.) are registered for commercialization. They were selected for fast growth, stem shape and disease resistance. The new selections (named MSA) includes genotypes with very high resistance to all the main diseases and to one insect, Phloeomizus passerinii (Sign.). Fast growth and disease resistance allow to produce wood with low environmental and economic costs; for this reason in some Italian Regions the introduction of a percentage of these clones in poplar stand is mandatory to obtain funding for their establishment (Rural Development Plan). To better understand the environmental advantages deriving from the use of these clones, in comparison with the old genotypes (particularly ‘I-214’), a ‘Life Cycle Assessment’ approach was applied considering as impact indicator the CO 2 equivalent emissions; from stoolbed to commercial stand, primary data were collected from an Italian experience. Firstly with the Inventory Analysis all the raw material, energy, wastes and emissions related were collected for each cultivation phase. The Analysis showed a reduction of 9% of CO 2 eq. ha -1 emitted, growing MSA instead of ‘I-214’. Considering the emissions per volume of wood, ‘I-214’ requests 47.5 kg CO 2 eq. per m 3 , compared with MSA that request 36.6 kg CO 2 eq. per m 3
Qualitative suggestions about chemical weed control of poplar in the nursery and possible improvement on the basis of experimental trials over fifteen years
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