Search results for " materia"
showing 10 items of 18071 documents
Fibre extraction from oleaginous flax for technical textile applications: influence of pre-processing parameters on fibre extraction yield, size dist…
2017
International audience; Cultivated primarily for its seeds, oleaginous flax could also be valued for the different fractions that can be extracted from the straw. However, as the straws are not harvested with the same technique and care than for the textile flax, the classical scutching technique cannot be used. As a consequence, an “all fibre” device was used to perform the separation of the different constituents of the oleaginous flax straws. The different fractions were quantified for two retting levels and for two degrees of rewetting of the stems. The physical and mechanical properties of fibres were then evaluated. It appears that the relative amount of fibres extracted from oleagino…
Conifer Needles as Thermoplastic Composite Fillers: Structure and Properties
2016
This study describes the properties of thermoplastic polymer composites based on polyethylene (of low and high density) and ethylene-propylene copolymers using various types of conifer needles (pine, spruce, fir, and cedar) as fillers. For the needles, thermogravimetric analysis (TGA) and TGA/Fourier transform infrared spectroscopy (TGA/FTIR) were performed to investigate their structures and thermal resistance, as required for the composite processing methods. Moreover, structural differences were studied for the analyzed fillers and composite materials (FTIR). The results were compared with the values obtained for composites with conifer wood flour. Composites with conifer needles (pine) …
Decomposition of nest material in tree holes and nest-boxes occupied by European Starlings Sturnus vulgaris: an experimental study
2017
Numerous bird species depend on the availability of tree cavities, and most non-excavators fill their cavities with considerable amounts of nest material. If not removed, this material can accumulate and render cavities unusable, as recorded in some nest-box studies. Data from earlier studies of tree cavities, however, showed that nest material can decrease mostly due to in situ decomposition, but the relative difference between nest decomposition in tree holes and nest-boxes is still unknown. We undertook parallel studies of decay in tree holes and nest-boxes used by European Starlings Sturnus vulgaris in oak-hornbeam stands (SW Poland). We inserted into its tree holes and nest-boxes litte…
Fast pyrolysis of hot-water-extracted and soda-AQ-delignified okra (Abelmoschus esculentus) and miscanthus (miscanthus x giganteus) stalks by Py-GC/MS
2018
Abstract The thermochemical behavior of various samples of okra ( Abelmoschus esculentus ) and miscanthus ( Miscanthus x giganteus ) stalks (initial, hot-water-extracted, and those from sulfur-free delignification) were studied by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). In all cases, major GC-amenable condensable products were measured semi-quantitatively and classified into several product groups. The formation of these product groups from different feedstock samples with varying mass portions of their structural constituents (carbohydrates and lignin) was investigated at 500 °C and 700 °C with a residence time of 5 s and 20 s. The main product groups were aliphatic comp…
Interaction of Oily Water with Floating Porous Ceramic and Immobilized Microorganisms
2018
Oily water was treated with porous ceramic granules and immobilized microorganisms. Floating granules with bulk density of 0.63-0.66 g cm-3were used. The sorption of motor oil was investigated for dry and wetted granules. Respiration experiments showed that microorganisms immobilized on floating ceramic carrier and treated with oily water were influenced by agitation of liquid. The treatment of oily water with low salinity (1-9 g L-1) showed that oil removal efficiency decreased after increasing water salinity. Likewise, oil removal efficiency decreased from 12 to 9% per gram of ceramic carrier after increasing the spill of oil from 9 to 35 g per square meter. Porous granules with immobiliz…
Utilization of lignin powder for manufacturing self-binding HDF
2017
Abstract The preparation of self-binding lignocellulosic fibreboards has been investigated. Different high-density fibreboards (HDF) were hot-pressed based on a mixture of grey alder (Alnus incana L. Moench) wood chips processed by steam explosion auto-hydrolysis (SE) and 15% or 25% lignin content from three different industrial sources: softwood kraft lignin (SWKL), soda wheat straw lignin (SoWhStL) and hydrolysis wheat straw lignin (HWhStL). Density, thickness swelling (TS) after immersion in water for 24 h, modulus of rupture (MOR), modulus of elasticity (MOE) and strength of internal bond (IB) of the board samples were determined. The amount (15% or 25%) and moisture content (MC) (18±1%…
Effect of Seasonal Storage on Single-Stem Bark Extractives of Norway Spruce (Picea abies)
2021
Increasing the net value of forestry side-streams has both ecological as well as economic benefits for emerging biorefining industries. Spruce bark represents one of the nature’s abundant sources of valuable extractives. In this study, the impact of storage on the quality and quantity of Norway spruce (Picea abies) extractives was examined as a function of storage time, environmental conditions and season (i.e., winter or summer). The bark from stored spruce saw logs was extracted with an accelerated solvent extractor (ASE) at 120 °C with hexane and water. The produced extracts were analysed qualitatively and quantitatively by gas chromatography with a flame ionisation detector (GC-FID) and…
The cork viewed from the inside
2015
International audience; Cork is the natural material stripped from the outer bark of cork oak. It is still the most used stopper to seal wine bottles and to preserve wine during storage. Cork stoppers are sorted in different classes according to apparent defects, named lenticels, which can be related to the cork macroporosity. The more lenticels there are, the worst cork quality is. The present work aims at investigating defects analysis of cork stoppers from two classes by comparing images recorded by digital photography and neutron imaging. Surface analysis of defects obtained from photography leads to more surface defects in class 4 (6.7%) than in class 0 (4.1%). Neutron radiography and …
Colorimetic biosensing dispositive based on reagentless hybrid biocomposite: Application to hydrogen peroxide determination
2016
Abstract An efficient approach to enhance the performance of colorimetric biosensors has been developed. The biosensor is based on the co-immobilization of the reagent 3,3′,5,5′-teramethylbencidine (TMB) and the enzyme horseradish peroxidase (HRP) in a PDMS-TEOS-SiO2NPs support. The HRP, in presence of H2O2, catalyzes the oxidation of TMB, producing a blue color. The generated biosensor, doped with the substrate (TMB) and the enzyme (HRP) (entrapped or adsorbed), has been used to determine H2O2 in real samples. Firstly, the immobilization of TMB and HRP in the composite has been studied in order to find the best suitable configuration. The kinetic parameters Vmax (maximum reaction rate) and…
Liquid Crystal Phases in Suspensions of Charged Plate-Like Particles
2012
International audience; Anisotropic interactions in colloidal suspensions have recently emerged as a route for the design of new soft materials. Nonisotropic particles can form nematic, smectic, hexatic, and columnar liquid crystals. Although the formation of these phases is well rationalized when excluded volume is solely at play, the role of electrostatic interactions still remains unclear and even less so when particles present a charge heterogeneity, for example, clays. Here, we use Monte Carlo simulations of concentrated suspensions of charged disk-like particles to reveal the role of Coulomb interactions and charge anisotropy underlying liquid crystal formation and structures. We obse…