A commercial three-layer particleboard served as model furniture for testing pretreatment with the oyster mushroom (Pleurotus ostreatus (Jacq.) P. Kumm.) over 9-, 12-, 16-, and 20-week periods based ...on the effects of reducing the enzymatic resistance of component cellulose. The effects of pretreatment were assessed based on Fourier-transform infrared spectroscopy (FTIR) of the treated particleboards, wherein indexes (peaks and peak ratios) connected with parameters influencing enzymatic cellulose hydrolysis were analysed. The data were analysed in two ways: the measurement of peak heights in both primary spectra and deconvoluted spectra. The peak heights for the determination of the total crystallinity index (TCI) were measured according to narrow and broad baselines. Time and how indexes are calculated were found to be the main factors significantly influencing the values of indexes of pretreatment in most cases. Until week 9, P. ostreatus pretreatment seems to be advantageous for biofuel production, which was illustrated by decreases in the intensity of the 1735 and 1505 cm−1 peaks and A1505/A1735, A1505/A1375, A1505/A1158, and A1505/A896 ratios in addition to a reduction in crystallinity.
This study aimed to determine glucose and xylose content by acid hydrolysis of wood samples, both unmodified and thermally modified (modification time was 2, 6, 10 hours), using high performance ...liquid chromatography. Optimization of the hydrolysis process on the native ash wood samples showed that 3 h was the best time in the hydrolysis process. After that time, 58.8% of glucose and 20.8% of xylose were obtained. In turn, chromatographic analysis showed incomplete hydrolysis of ash wood samples, which were modified in a nitrogen atmosphere, especially at shorter times (2 and 6 h) of modification. With longer modification times (10 h), the hydrolysis of ash wood samples was completed. The above mentioned problem was caused mainly by the increase of cellulose crystallinity degree. The decrease of this parameter was observed only after 10 h of thermal modification, which would facilitate the process of acidic hydrolysis. Additionally, it was observed that the thermal modification of ash wood at 190 °C in a nitrogen atmosphere for 10 h caused a drastic decrease in the xylose content (from 20.8% to 8.0%) and only a slight decrease in the glucose content (from 58.8% to 54.9%).
A commercial three-layer particleboard served as model furniture for testing pretreatment with the oyster mushroom (Pleurotus ostreatus (Jacq.) P. Kumm.) over 9-, 12-, 16-, and 20-week periods based ...on the effects of reducing the enzymatic resistance of component cellulose. The effects of pretreatment were assessed based on Fourier-transform infrared spectroscopy (FTIR) of the treated particleboards, wherein indexes (peaks and peak ratios) connected with parameters influencing enzymatic cellulose hydrolysis were analysed. The data were analysed in two ways: the measurement of peak heights in both primary spectra and deconvoluted spectra. The peak heights for the determination of the total crystallinity index (TCI) were measured according to narrow and broad baselines. Time and how indexes are calculated were found to be the main factors significantly influencing the values of indexes of pretreatment in most cases. Until week 9, P. ostreatus pretreatment seems to be advantageous for biofuel production, which was illustrated by decreases in the intensity of the 1735 and 1505 cmsup.−1 peaks and Asub.1505 /Asub.1735 , Asub.1505 /Asub.1375 , Asub.1505 /Asub.1158 , and Asub.1505 /Asub.896 ratios in addition to a reduction in crystallinity.
The aim of this study was to assess the energy consumption during milling and cutting-milling of pine and poplar shavings and the determination of particle size distribution (PSD) characteristics and ...mechanical properties of these materials. Cutting-milling process required less energy (in kJ·kg
–1
) than milling but maximum mass flow rate of shavings was significantly higher and thus the effective power requirement of the knife mill during cutting also was higher. Comminution of plastic poplar shavings was more energy-consuming than harder pine shavings. These features influenced PSD, which was approximated with four mathematical models: Rosin–Rammler-Sperling-Bennett (RRSB), normal, logistic and lognormal. On the basis of the best fitting (
R
adj
2
) for RRSB, detailed PSD parameters were calculated and all PSDs were described as ‘mesokurtic’, ‘fine skewed’ and ‘well-graded’. In comparison to milled shavings, cut-milled shavings had higher density, but were less compressible and had lower unconfined yield strength. However, cut-milled shavings had higher flowability because of lower cohesion and internal friction angles, because after cutting-milling particles were more spherical than elongated particles after milling. Cut-milled poplar shavings had more favourable mechanical parameters and better PSD characteristics, but required more energy for comminution than pine shavings.
The focus of this study was to compare the volatile compounds of unfermented and fermented milk samples containing Lactobacillus casei DN-114 001. Samples were analysed by headspace solid phase micro ...extraction-gas chromatography-mass spectrometry and pH changes were monitored on day zero and at weeks 2 and 4 of storage at 6 °C. Acetic acid was present as the dominant compound in all fermented samples and non-fermented samples from the 2nd week of storage. Other identified compounds were: 2-butanone, ethanol, 2-pentanone, 2-heptanone, amylol, acetoin, 2-nonanone, propionic acid, butyric acid, isovaleric acid, caproic acid, dodecanol, and caprylic acid. Comparison of the volatile compound profiles using cluster analysis revealed a similarity of volatile compounds of fermented and unfermented milk samples stored for 4 weeks. Cluster-analysis comparison and an artificial neural network model enabled demonstration of the close relationship between model non-fermented milk and a commercially-available milk product.
The aim of the study was to investigate the densification characteristics of raw, milled, and cut-milled pine and poplar shavings and determine the strength parameters of pellets, pastilles, and ...granules. In producing agglomerates from hard pine shavings compared to plastic poplar shavings, 19% more specific compaction work was required with over 2-times more specific work to push the agglomerate out of the die opening. Pine agglomerates exhibited lower linear expansion than poplar agglomerates, achieving a higher single density. Due to the elevated content of thermoplastic lignin in the wood (30.7 and 18.4%, respectively), pine agglomerates demonstrated superior radial compression strength parameters, including specific deformation energy, maximum tensile stresses at which agglomerates cracked, and the highest modulus of elasticity. Agglomerates made of cut-milled shavings had the highest single density, but their tensile strength was significantly lower than that of agglomerates made from raw shavings. The susceptibility to densification of the shavings during sequentially repeated densification of small doses during pellet production was the highest, resulting in pellets characterised by the smallest linear and radial expansion, as well as the highest single density of 1081 kg·m
–3
and tensile strength among agglomerates. The smallest single density and strength were observed in granules produced with parameters recommended for particleboard production: a temperature of 170 °C and an agglomeration pressure of 12 MPa, compared to 93 °C and 70 MPa for pellets and pastilles, respectively. The higher temperature did not compensate for the much lower pressure. Shavings compaction parameters for granules are not recommended for particleboard production without a binder, typically urea–formaldehyde resin.
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