The aim of this study was to determine the changes occurring in the wood cellulose of the fast-gr... more The aim of this study was to determine the changes occurring in the wood cellulose of the fast-growing poplar (Populus deltoides x maximowiczii) under the influence of steam explosion (SE) pretreatment. Cellulose from native wood and after pretreatment at 160°C and 205°C was isolated. Cellulose polymerization degree by size exclusion chromatography (SEC) and cellulose crystallinity index by Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR) were determined. The profiles of sugars in the native wood and in the solid fraction after pretreatment (using the acid hydrolysis method) were also determined. In addition, the profile of monosaccharides in the liquid fraction obtained after steam explosion and in the liquid fraction after acid hydrolysis of the oligosaccharides were investigated using high-performance liquid chromatography (HPLC). This allowed to determine the change in the content of hexoses and pentoses in the studied material. The behavior of cel...
Termickým zaťažením dreva dochádza k významným zmenám v jeho chemickom zložení a vlastnostiach. Š... more Termickým zaťažením dreva dochádza k významným zmenám v jeho chemickom zložení a vlastnostiach. Štúdium týchto zmien je dôležité tiež z pohľadu požiarnej bezpečnosti pri využívaní dreva ako stavebného materiálu. V tejto práci boli vzorky smrekového dreva (Picea abies L. Karst.) tepelne zaťažené pri teplotách 100, 150, 200, 220, 240, 260, 280 a 300 °C po dobu 1, 3 a 5 hodín za prístupu vzduchu. Hmotnostný úbytok sa výrazne zvyšuje nad teplotou 220 °C počas celej doby termického zaťaženia. Zmeny v dreve spôsobené termickou úpravou boli sledované pomocou ATR-FTIR spektroskopie. Získané výsledky poukazujú na kondenzačné reakcie lignínu a zmeny v jeho štruktúre. Pri teplote okolo 240 °C bol pozorovaný začiatok degradácie celulózy.The thermal treatment of wood causes signifi cant alterations in its chemical composition and properties. The study of these alterations is important also from view point of fi re safety at the wood utilisation as a construction material. In this study the sampl...
Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology, 2011
Evaluation of recycled fibers by hydrolysis. Pulp and paper industry produce a lot of waste which... more Evaluation of recycled fibers by hydrolysis. Pulp and paper industry produce a lot of waste which contains the rest of pulp fibers. Solution is burning and gaining energy. The most effective way to execute pulps fibers are hydrolyses. Acquirement sugars maybe further utilize e.g. for fermentation of monosaccharide on ethanol (how potential raw material, which replacement fossil fuels). In this paper there is described influence of acid hydrolysis with 1 % H2SO4 (temperature 140, 160 °C, time 30, 60, 90, 120 min, hydromodule 1:40 (w/v)) on samples of recycling fibers from waste paper. Rhamnose, arabinose, xylose, manose and glucose were determined in hydrolysate by the gas chromatography. Volatile compounds like acetic acid, propionic acid, methanol, ethanol and 2-furaldehyde were specified by the gas chromatography.
Liquid hot-water pretreatment is a hydrothermal process that does not require rapid decompression... more Liquid hot-water pretreatment is a hydrothermal process that does not require rapid decompression and the addition of any catalyst or chemicals. It allows the removal of hemicelluloses from lignocellulosic materials, which makes the cellulose more accessible to hydrolysis. In this study, willow wood (Salix alba L.) was subjected to hot-water pretreatment at varying pretreatment times and the temperature of 160 °C. Then, the native willow wood and the hydrolysates were analysed to determine their content of saccharides according to the National Renewable Energy Laboratory analytical procedure. It was determined that the native willow wood contained glucose (49.72%), xylose (12.84%), galactose (2.90%), arabinose (2.00%) and mannose (1.87%), which were also found in the hydrolysates. The optimal amount of saccharides in the hydrolysates was found for a pretreatment time of 60 min (at 160 °C).
The experimental tests of selected tribo-pair in three loading cycles were compared in this paper... more The experimental tests of selected tribo-pair in three loading cycles were compared in this paper. Tests were performed with mineral transmission oil and ecological synthetic ester base oil, which were dropping by Gravity Force through the overhead part of measuring head of the laboratory testing device. The influence of factors (load cycle, lubricant) on the bearing shells and shafts was statistically verified by analysis of variance (ANOVA). The relevant differences between average values of each specimens were defined using Duncan`s multiple range test with a p-value of 0.05. Dynamically loaded tribo-pairs showed bigger mass losses and higher friction coefficients compared to the static cycle in conditions of the experiment, regardless of the lubrication method. This effect was even more significant in environment lubricated with mineral oil. Results confirmed that processes of dynamic loading play a significant role in evaluating selected parameters (wear, friction force, friction coefficient) tribological nodes of agricultural, forestry and other industrial machines.
Abstract Liquid hot water pretreatment modifies the physiochemical features of plant cell walls, ... more Abstract Liquid hot water pretreatment modifies the physiochemical features of plant cell walls, including cell wall chemistry and composition, as well as cellulose and lignin ultrastuctures. This study was designed to assess how the presence of insoluble lignin, lignin monomer composition, and the macromolecular traits of deconstructed cellulose influence the content of glucose, xylose and total saccharides within solids during liquid hot water pretreatment of hybrid poplar wood. Hydrothermal pretreatments at 180 °C for both 5 and 10 min were found to be the most effective conditions to achieve maximum glucose content. Under these pretreatment conditions, it was possible to achieve a more than 50% decrease in xylose content due to the solubilization of hemicelluloses, a low lignin content, and severe drops in the macromolecular traits of cellulose such as number-average molecular weight, weight-average molecular weight, degree of polymerization and polydispersity index. A continuous increase in the severity of the hydrothermal pretreatment resulted in a decrease in glucose content, an increase in insoluble lignin content, and an ongoing scission of cellulose chains. The amounts of glucose, xylose and total saccharides within solids were negatively influenced by the insoluble lignin content and the syringyl-to-guaiacyl ratio in lignin, but at the same time positively correlated with the cellulose degree of polymerization, weight-average molecular weight and hydrogen bond intensity. Four groups of compact clusters of hydrothermal pretreatment conditions were identified in a multivariate wood trait analysis.
The visual inspection of fresh cut spruce wood (Picea abies, L. Karst.) showed the variability of... more The visual inspection of fresh cut spruce wood (Picea abies, L. Karst.) showed the variability of its colour. Wood visual inspection is a part of wood quality assessment, for example, prior to or after its processing. The detail spruce wood colour analysis was performed using spectrophotometric data. The colour was measured by the bench-top spectrophotometer CM-5 Konica Minolta. The spectrophotometer was calibrated with a built-in white standard and on air. The whole analysis was performed in an xy chromaticity diagram supplemented with coordinate Y and CIE L*a*b* colour spaces. The ratio of the white chromophore amount to the amount of all achromatic chromophores is related to the Y coordinate. The ratio of the chromatic chromophore amount to all chromophores amount is saturation. The constructed model of the spruce wood colour is composed of four chromophores. The white chromophore belongs to holocellulose. The black chromophore belongs to lignin. The saturation is influenced by t...
Biobutanol is a renewable, less polluting, and potentially viable alternative fuel to conventiona... more Biobutanol is a renewable, less polluting, and potentially viable alternative fuel to conventional gasoline. Biobutanol can be produced from same sources as bioethanol, and it has many advantages over the widespread bioethanol. This paper systematically analyzes biobutanol fuel as an alternative to bioethanol in alcohol–gasoline mixtures and the physicochemical properties. Based on the conducted analyses, it was found that biobutanol mixtures have a more suitable behavior of vapor pressure without the occurrence of azeotrope, do not form a separate phase in lower temperature, it has higher energy density, but slightly reduce the octane number and a have higher viscosity. However, in general, biobutanol has many advantageous properties that could allow its use in gasoline engines instead of the commonly used bioethanol.
This article focuses on the issue of motor oils used in the engines of non-road mobile machinery ... more This article focuses on the issue of motor oils used in the engines of non-road mobile machinery (NRMM), more specifically tractors. The primary goal of the paper is to determine the appropriate replacement interval for these oils. The physical properties of the examined samples were first determined by conventional instruments. Furthermore, the concentrations of abrasive metals, contaminants, and additive elements were measured using an optical emission spectrometer. Lastly, the content of water, fuel, and glycol and the products of oxidation, nitration, and sulfation were determined by using infrared spectrometry. The measured values were compared to the limit values. Based on the processing and evaluation of these analyses, the overall condition of the oils was assessed and subsequently the optimal exchange interval of the examined oils was determined. In addition, a risk analysis of the outage was performed. Due to the high yields of crops, farmers can lose a significant amount ...
There is a global need to increase the production of alternative sources of energy due to many is... more There is a global need to increase the production of alternative sources of energy due to many issues related to conventional sources, such as environmental degradation or energy security. In this paper, decentralized liquefied natural gas production is analyzed. Liquefied natural gas, according to the analysis, can be considered a viable alternative even for decentralized applications Design and economic analysis of a small-scale biogas LNG plan together with the necessary technology and economic evaluation are presented in the paper. The results show that a project of the proposed size (EUR 3 million) offers a relatively good profitability level. Specifically, the net present value of the project is mostly positive (around EUR 0.1 million up to EUR 0.8 million). Therefore, based on the research, small LNG plants operating across the continent can be recommended for the processing of local sources of biogas.
Wood stock in a warehouse is a necessary precondition for reliable manufacturing. However, wood c... more Wood stock in a warehouse is a necessary precondition for reliable manufacturing. However, wood can degrade and lose the matter during storage. “Dry-matter loss (DML)” is used to quantify the degradation following the changes in weight of a wood substance. The proposed calculation of DML is based on using parallel figures. The calculated loss of spruce wood substance harvested in winter during a six-month period was 4.5%. The estimated annual loss of wood substance was 5.7%. The loss was caused by a factor with a gradually eliminated effect. The changes in the chemical composition of wood substance were not proportional to the original amount of the isolated chemical substances. Hemicelluloses and lignin suffered from the loss faster than there was a change in the DML of spruce wood. Hemicelluloses were the most unstable isolated compound, with an increased rate of change during the first four months. The number of extractive substances significantly decreased during two months of s...
Fungi play a critical role in the decomposition of wood and wood-based products in use. The abili... more Fungi play a critical role in the decomposition of wood and wood-based products in use. The ability of decaying fungi to cause degradation of polysaccharides and lignin in the thermally modified Norway spruce (Picea abies L. Karst.) wood was examined with pure culture decomposition tests in laboratory conditions using the brown-rot fungus Serpula lacrymans (Schumacher ex Fries) S.F. Gray and white-rot fungus Trametes versicolor (Linnaeus ex Fries) Pilat. Spruce wood samples were primary thermally treated under atmospheric pressure at the temperatures of 100, 150, 200, 220, 240 and 260 °C during 1, 3 and 5 h, whereby larger losses in their mass, holocellulose, mannose and xylose were achieved at harder thermal regimes. Meanwhile, the holocellulose percent content reduced considerably, and the percent content of lignin increased sharply. Spruce wood thermally modified at and above 200 °C better resisted to brown-rot fungus S. lacrymans than the white-rot fungus T. versicolor. Due to t...
This paper presents the differences in the color changes of unsteamed and steamed beech wood (Fag... more This paper presents the differences in the color changes of unsteamed and steamed beech wood (Fagus sylvatica L.) caused by long-term exposure to sunlight on the surface of wood in interiors for 36 months. The light white-gray color of the yellow tinge of native beech wood darkened under the influence of sunlight, and the wood took on a pale brown color of yellow tinge. The degree of darkening and browning is quantified by the value of the total color difference ∆E* = 13.0. The deep brown-red color of steamed beech under the influence of sunlight during the exposure brightened, and the surface of the wood took on a pale brown hue. The degree of lightening of the color of steamed beech wood in the color space CIE L*a*b* is quantified by the value of the total color difference ∆E* = 7.1. A comparison of the color changes of unsteamed and steamed beech wood through the total color difference ∆E* due to daylight shows that the surface of steamed beech wood shows 52.2% smaller changes th...
The bonding of wood with assembly adhesives is crucial for manufacturing wood composites, such as... more The bonding of wood with assembly adhesives is crucial for manufacturing wood composites, such as solid wood panels, glulam, furniture parts, and sport and musical instruments. This work investigates 13 hardwoods—bangkirai, beech, black locust, bubinga, ipé, iroko, maçaranduba, meranti, oak, palisander, sapelli, wengé and zebrano—and analyzes the impact of their selected structural and physical characteristics (e.g., the density, cold water extract, pH value, roughness, and wettability) on the adhesion strength with the polyvinyl acetate (PVAc) adhesive Multibond SK8. The adhesion strength of the bonded hardwoods, determined by the standard EN 205, ranged in the dry state from 9.5 MPa to 17.2 MPa, from 0.6 MPa to 2.6 MPa in the wet state, and from 8.5 MPa to 19.2 MPa in the reconditioned state. The adhesion strength in the dry state of the bonded hardwoods was not influenced by their cold water extracts, pH values, or roughness parallel with the grain. On the contrary, the adhesion ...
Chemical composition and morphological properties of Norway spruce wood and bark were evaluated. ... more Chemical composition and morphological properties of Norway spruce wood and bark were evaluated. The extractives, cellulose, hemicelluloses, and lignin contents were determined by wet chemistry methods. The dimensional characteristics of the fibers (length and width) were measured by Fiber Tester. The results of the chemical analysis of wood and bark show the differences between the trunk and top part, as well as in the different heights of the trunk and in the cross section of the trunk. The biggest changes were noticed between bark trunk and bark top. The bark top contains 10% more of extractives and 9.5% less of lignin. Fiber length and width depends on the part of the tree, while the average of these properties are larger depending on height. Both wood and bark from the trunk contains a higher content of fines (fibers <0.3 mm) and less content of longer fibers (>0.5 mm) compared to the top. During storage, it reached a decrease of extractives mainly in bark. Wood from the ...
The chemical properties of willow were studied following liquid hot water pretreatment. Three dif... more The chemical properties of willow were studied following liquid hot water pretreatment. Three different temperatures of liquid hot water pretreatment were used (160, 180, and 200 °C) for periods of 30, 60, 120, and 240 min. The contents of extractives, lignin, holocellulose, glucose, and xylose was determined. Compared with the original sample, the results indicated that lignin and extractives content increased after pretreatment. Further, the content of xylose decreased significantly with increasing pretreatment time for all three temperatures. The highest glucose content was obtained under the conditions of 180 °C for 240 min. In addition, a significant correlation was found between the content of xylose in the solid fraction and the severity factor of treatment. To determine the changes in cellulose crystallinity, the total crystallinity index (TCI) and the lateral order index (LOI) were calculated from the Fourier-transform infrared spectroscopy spectra of cellulose. An increase...
Spruce boards with dimensions of 500 × 500 × 100 mm were thermally loaded during 90 minutes accor... more Spruce boards with dimensions of 500 × 500 × 100 mm were thermally loaded during 90 minutes according the temperature curves PAR1, PAR2 and TNK. In the samples there was determined amount of extractive matters and cellulose. The alterations of degree of polymerisation (DP) and molecular weight distribution (MWD) were analyzed by gel permeation chromatography (GPC) of cellulose tricarbanilates. The amount of cellulose and extractive matters increased and cellulose DP decreased after the thermal loading. The highest decrease of cellulose DP was determined at the temperature curve PAR1 (from 870 to 604), less at the PAR2 (from 845 to 660) and at the least at the TNK (from 890 to 862).
The interaction of water and oak wood is common in outdoor expositions and will remain a probable... more The interaction of water and oak wood is common in outdoor expositions and will remain a probable occurrence in the future. New insights into the recognition of a cell wall saturation limit are presented by a double-weighing method at 20 °C. The cell wall saturation limit, as the property of thermally modified oak wood, is significantly influenced by different treatment temperatures (20, 160, 180, 210 and 240 °C) on a 5% alpha level. A significantly higher equilibrium moisture content was reached by thermally modified oak wood at a temperature of 20 °C and relative humidity of 65% after its equilibrium in the water-in-reservoir. Moreover, the results are used in the treatment of woodchips to produce cellulose or decomposition of thermally modified wood to its basic chemical components. The investigated properties of cellulose revealed its relationship with water. The number of water molecules bonded to a cellulose chain was correlated with other measured compositions: average molecu...
Alterations in the chemical composition of silver fir wood (Abies alba L.) during thermal treatme... more Alterations in the chemical composition of silver fir wood (Abies alba L.) during thermal treatment were investigated. The mass loss, extractives, saccharides, and lignin were determined. In both untreated and heat-treated wood, extractives were determined according to ASTM D1107-96, lignin content according to ASTM D1106-96, and saccharides by high-performance liquid chromatography. During the thermal treatment, mass loss and the chemical composition of the wood were found to change. The extractives content decreased up to 200 °C, and then increased at higher temperatures. The mass loss increased with increasing temperature and time of thermal treatment. A relative increase in lignin content and a decrease in saccharides were observed. The color of the wood was stable at temperatures up to 150 °C when treated up to 1 h. A change in color significantly depends on thermal energy intake above that level. Saccharides, color coordinates L* and b*, lignin, mass loss, temperature, and color change ΔE* strongly vary together. These investigated properties of fir wood set out the boundaries for high-temperature treatment and show potential for utilization of this species.
Correlations between the chemical composition and physical properties of oak wood were studied by... more Correlations between the chemical composition and physical properties of oak wood were studied by correlation analysis. The specimens were produced from thermally treated oak wood at temperatures of 20 °C, 160 °C, 180 °C, 210 °C, and 240 °C. The physical properties were affected by the chemical composition of oak wood. The correlations of equilibrium moisture content (EMC) and oak density at EMC were similar, in accordance with the investigated properties. Oak end hardness was affected by treatment temperature. The depth of indentation significantly affected the hardness. Mass specific heat capacity and effusivity were positively correlated with EMC, sugars, holocellulose, cellulose traits, and ash and negatively affected by total extractives. Thermal diffusivity was slightly affected by treatment temperature.
The aim of this study was to determine the changes occurring in the wood cellulose of the fast-gr... more The aim of this study was to determine the changes occurring in the wood cellulose of the fast-growing poplar (Populus deltoides x maximowiczii) under the influence of steam explosion (SE) pretreatment. Cellulose from native wood and after pretreatment at 160°C and 205°C was isolated. Cellulose polymerization degree by size exclusion chromatography (SEC) and cellulose crystallinity index by Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR) were determined. The profiles of sugars in the native wood and in the solid fraction after pretreatment (using the acid hydrolysis method) were also determined. In addition, the profile of monosaccharides in the liquid fraction obtained after steam explosion and in the liquid fraction after acid hydrolysis of the oligosaccharides were investigated using high-performance liquid chromatography (HPLC). This allowed to determine the change in the content of hexoses and pentoses in the studied material. The behavior of cel...
Termickým zaťažením dreva dochádza k významným zmenám v jeho chemickom zložení a vlastnostiach. Š... more Termickým zaťažením dreva dochádza k významným zmenám v jeho chemickom zložení a vlastnostiach. Štúdium týchto zmien je dôležité tiež z pohľadu požiarnej bezpečnosti pri využívaní dreva ako stavebného materiálu. V tejto práci boli vzorky smrekového dreva (Picea abies L. Karst.) tepelne zaťažené pri teplotách 100, 150, 200, 220, 240, 260, 280 a 300 °C po dobu 1, 3 a 5 hodín za prístupu vzduchu. Hmotnostný úbytok sa výrazne zvyšuje nad teplotou 220 °C počas celej doby termického zaťaženia. Zmeny v dreve spôsobené termickou úpravou boli sledované pomocou ATR-FTIR spektroskopie. Získané výsledky poukazujú na kondenzačné reakcie lignínu a zmeny v jeho štruktúre. Pri teplote okolo 240 °C bol pozorovaný začiatok degradácie celulózy.The thermal treatment of wood causes signifi cant alterations in its chemical composition and properties. The study of these alterations is important also from view point of fi re safety at the wood utilisation as a construction material. In this study the sampl...
Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology, 2011
Evaluation of recycled fibers by hydrolysis. Pulp and paper industry produce a lot of waste which... more Evaluation of recycled fibers by hydrolysis. Pulp and paper industry produce a lot of waste which contains the rest of pulp fibers. Solution is burning and gaining energy. The most effective way to execute pulps fibers are hydrolyses. Acquirement sugars maybe further utilize e.g. for fermentation of monosaccharide on ethanol (how potential raw material, which replacement fossil fuels). In this paper there is described influence of acid hydrolysis with 1 % H2SO4 (temperature 140, 160 °C, time 30, 60, 90, 120 min, hydromodule 1:40 (w/v)) on samples of recycling fibers from waste paper. Rhamnose, arabinose, xylose, manose and glucose were determined in hydrolysate by the gas chromatography. Volatile compounds like acetic acid, propionic acid, methanol, ethanol and 2-furaldehyde were specified by the gas chromatography.
Liquid hot-water pretreatment is a hydrothermal process that does not require rapid decompression... more Liquid hot-water pretreatment is a hydrothermal process that does not require rapid decompression and the addition of any catalyst or chemicals. It allows the removal of hemicelluloses from lignocellulosic materials, which makes the cellulose more accessible to hydrolysis. In this study, willow wood (Salix alba L.) was subjected to hot-water pretreatment at varying pretreatment times and the temperature of 160 °C. Then, the native willow wood and the hydrolysates were analysed to determine their content of saccharides according to the National Renewable Energy Laboratory analytical procedure. It was determined that the native willow wood contained glucose (49.72%), xylose (12.84%), galactose (2.90%), arabinose (2.00%) and mannose (1.87%), which were also found in the hydrolysates. The optimal amount of saccharides in the hydrolysates was found for a pretreatment time of 60 min (at 160 °C).
The experimental tests of selected tribo-pair in three loading cycles were compared in this paper... more The experimental tests of selected tribo-pair in three loading cycles were compared in this paper. Tests were performed with mineral transmission oil and ecological synthetic ester base oil, which were dropping by Gravity Force through the overhead part of measuring head of the laboratory testing device. The influence of factors (load cycle, lubricant) on the bearing shells and shafts was statistically verified by analysis of variance (ANOVA). The relevant differences between average values of each specimens were defined using Duncan`s multiple range test with a p-value of 0.05. Dynamically loaded tribo-pairs showed bigger mass losses and higher friction coefficients compared to the static cycle in conditions of the experiment, regardless of the lubrication method. This effect was even more significant in environment lubricated with mineral oil. Results confirmed that processes of dynamic loading play a significant role in evaluating selected parameters (wear, friction force, friction coefficient) tribological nodes of agricultural, forestry and other industrial machines.
Abstract Liquid hot water pretreatment modifies the physiochemical features of plant cell walls, ... more Abstract Liquid hot water pretreatment modifies the physiochemical features of plant cell walls, including cell wall chemistry and composition, as well as cellulose and lignin ultrastuctures. This study was designed to assess how the presence of insoluble lignin, lignin monomer composition, and the macromolecular traits of deconstructed cellulose influence the content of glucose, xylose and total saccharides within solids during liquid hot water pretreatment of hybrid poplar wood. Hydrothermal pretreatments at 180 °C for both 5 and 10 min were found to be the most effective conditions to achieve maximum glucose content. Under these pretreatment conditions, it was possible to achieve a more than 50% decrease in xylose content due to the solubilization of hemicelluloses, a low lignin content, and severe drops in the macromolecular traits of cellulose such as number-average molecular weight, weight-average molecular weight, degree of polymerization and polydispersity index. A continuous increase in the severity of the hydrothermal pretreatment resulted in a decrease in glucose content, an increase in insoluble lignin content, and an ongoing scission of cellulose chains. The amounts of glucose, xylose and total saccharides within solids were negatively influenced by the insoluble lignin content and the syringyl-to-guaiacyl ratio in lignin, but at the same time positively correlated with the cellulose degree of polymerization, weight-average molecular weight and hydrogen bond intensity. Four groups of compact clusters of hydrothermal pretreatment conditions were identified in a multivariate wood trait analysis.
The visual inspection of fresh cut spruce wood (Picea abies, L. Karst.) showed the variability of... more The visual inspection of fresh cut spruce wood (Picea abies, L. Karst.) showed the variability of its colour. Wood visual inspection is a part of wood quality assessment, for example, prior to or after its processing. The detail spruce wood colour analysis was performed using spectrophotometric data. The colour was measured by the bench-top spectrophotometer CM-5 Konica Minolta. The spectrophotometer was calibrated with a built-in white standard and on air. The whole analysis was performed in an xy chromaticity diagram supplemented with coordinate Y and CIE L*a*b* colour spaces. The ratio of the white chromophore amount to the amount of all achromatic chromophores is related to the Y coordinate. The ratio of the chromatic chromophore amount to all chromophores amount is saturation. The constructed model of the spruce wood colour is composed of four chromophores. The white chromophore belongs to holocellulose. The black chromophore belongs to lignin. The saturation is influenced by t...
Biobutanol is a renewable, less polluting, and potentially viable alternative fuel to conventiona... more Biobutanol is a renewable, less polluting, and potentially viable alternative fuel to conventional gasoline. Biobutanol can be produced from same sources as bioethanol, and it has many advantages over the widespread bioethanol. This paper systematically analyzes biobutanol fuel as an alternative to bioethanol in alcohol–gasoline mixtures and the physicochemical properties. Based on the conducted analyses, it was found that biobutanol mixtures have a more suitable behavior of vapor pressure without the occurrence of azeotrope, do not form a separate phase in lower temperature, it has higher energy density, but slightly reduce the octane number and a have higher viscosity. However, in general, biobutanol has many advantageous properties that could allow its use in gasoline engines instead of the commonly used bioethanol.
This article focuses on the issue of motor oils used in the engines of non-road mobile machinery ... more This article focuses on the issue of motor oils used in the engines of non-road mobile machinery (NRMM), more specifically tractors. The primary goal of the paper is to determine the appropriate replacement interval for these oils. The physical properties of the examined samples were first determined by conventional instruments. Furthermore, the concentrations of abrasive metals, contaminants, and additive elements were measured using an optical emission spectrometer. Lastly, the content of water, fuel, and glycol and the products of oxidation, nitration, and sulfation were determined by using infrared spectrometry. The measured values were compared to the limit values. Based on the processing and evaluation of these analyses, the overall condition of the oils was assessed and subsequently the optimal exchange interval of the examined oils was determined. In addition, a risk analysis of the outage was performed. Due to the high yields of crops, farmers can lose a significant amount ...
There is a global need to increase the production of alternative sources of energy due to many is... more There is a global need to increase the production of alternative sources of energy due to many issues related to conventional sources, such as environmental degradation or energy security. In this paper, decentralized liquefied natural gas production is analyzed. Liquefied natural gas, according to the analysis, can be considered a viable alternative even for decentralized applications Design and economic analysis of a small-scale biogas LNG plan together with the necessary technology and economic evaluation are presented in the paper. The results show that a project of the proposed size (EUR 3 million) offers a relatively good profitability level. Specifically, the net present value of the project is mostly positive (around EUR 0.1 million up to EUR 0.8 million). Therefore, based on the research, small LNG plants operating across the continent can be recommended for the processing of local sources of biogas.
Wood stock in a warehouse is a necessary precondition for reliable manufacturing. However, wood c... more Wood stock in a warehouse is a necessary precondition for reliable manufacturing. However, wood can degrade and lose the matter during storage. “Dry-matter loss (DML)” is used to quantify the degradation following the changes in weight of a wood substance. The proposed calculation of DML is based on using parallel figures. The calculated loss of spruce wood substance harvested in winter during a six-month period was 4.5%. The estimated annual loss of wood substance was 5.7%. The loss was caused by a factor with a gradually eliminated effect. The changes in the chemical composition of wood substance were not proportional to the original amount of the isolated chemical substances. Hemicelluloses and lignin suffered from the loss faster than there was a change in the DML of spruce wood. Hemicelluloses were the most unstable isolated compound, with an increased rate of change during the first four months. The number of extractive substances significantly decreased during two months of s...
Fungi play a critical role in the decomposition of wood and wood-based products in use. The abili... more Fungi play a critical role in the decomposition of wood and wood-based products in use. The ability of decaying fungi to cause degradation of polysaccharides and lignin in the thermally modified Norway spruce (Picea abies L. Karst.) wood was examined with pure culture decomposition tests in laboratory conditions using the brown-rot fungus Serpula lacrymans (Schumacher ex Fries) S.F. Gray and white-rot fungus Trametes versicolor (Linnaeus ex Fries) Pilat. Spruce wood samples were primary thermally treated under atmospheric pressure at the temperatures of 100, 150, 200, 220, 240 and 260 °C during 1, 3 and 5 h, whereby larger losses in their mass, holocellulose, mannose and xylose were achieved at harder thermal regimes. Meanwhile, the holocellulose percent content reduced considerably, and the percent content of lignin increased sharply. Spruce wood thermally modified at and above 200 °C better resisted to brown-rot fungus S. lacrymans than the white-rot fungus T. versicolor. Due to t...
This paper presents the differences in the color changes of unsteamed and steamed beech wood (Fag... more This paper presents the differences in the color changes of unsteamed and steamed beech wood (Fagus sylvatica L.) caused by long-term exposure to sunlight on the surface of wood in interiors for 36 months. The light white-gray color of the yellow tinge of native beech wood darkened under the influence of sunlight, and the wood took on a pale brown color of yellow tinge. The degree of darkening and browning is quantified by the value of the total color difference ∆E* = 13.0. The deep brown-red color of steamed beech under the influence of sunlight during the exposure brightened, and the surface of the wood took on a pale brown hue. The degree of lightening of the color of steamed beech wood in the color space CIE L*a*b* is quantified by the value of the total color difference ∆E* = 7.1. A comparison of the color changes of unsteamed and steamed beech wood through the total color difference ∆E* due to daylight shows that the surface of steamed beech wood shows 52.2% smaller changes th...
The bonding of wood with assembly adhesives is crucial for manufacturing wood composites, such as... more The bonding of wood with assembly adhesives is crucial for manufacturing wood composites, such as solid wood panels, glulam, furniture parts, and sport and musical instruments. This work investigates 13 hardwoods—bangkirai, beech, black locust, bubinga, ipé, iroko, maçaranduba, meranti, oak, palisander, sapelli, wengé and zebrano—and analyzes the impact of their selected structural and physical characteristics (e.g., the density, cold water extract, pH value, roughness, and wettability) on the adhesion strength with the polyvinyl acetate (PVAc) adhesive Multibond SK8. The adhesion strength of the bonded hardwoods, determined by the standard EN 205, ranged in the dry state from 9.5 MPa to 17.2 MPa, from 0.6 MPa to 2.6 MPa in the wet state, and from 8.5 MPa to 19.2 MPa in the reconditioned state. The adhesion strength in the dry state of the bonded hardwoods was not influenced by their cold water extracts, pH values, or roughness parallel with the grain. On the contrary, the adhesion ...
Chemical composition and morphological properties of Norway spruce wood and bark were evaluated. ... more Chemical composition and morphological properties of Norway spruce wood and bark were evaluated. The extractives, cellulose, hemicelluloses, and lignin contents were determined by wet chemistry methods. The dimensional characteristics of the fibers (length and width) were measured by Fiber Tester. The results of the chemical analysis of wood and bark show the differences between the trunk and top part, as well as in the different heights of the trunk and in the cross section of the trunk. The biggest changes were noticed between bark trunk and bark top. The bark top contains 10% more of extractives and 9.5% less of lignin. Fiber length and width depends on the part of the tree, while the average of these properties are larger depending on height. Both wood and bark from the trunk contains a higher content of fines (fibers <0.3 mm) and less content of longer fibers (>0.5 mm) compared to the top. During storage, it reached a decrease of extractives mainly in bark. Wood from the ...
The chemical properties of willow were studied following liquid hot water pretreatment. Three dif... more The chemical properties of willow were studied following liquid hot water pretreatment. Three different temperatures of liquid hot water pretreatment were used (160, 180, and 200 °C) for periods of 30, 60, 120, and 240 min. The contents of extractives, lignin, holocellulose, glucose, and xylose was determined. Compared with the original sample, the results indicated that lignin and extractives content increased after pretreatment. Further, the content of xylose decreased significantly with increasing pretreatment time for all three temperatures. The highest glucose content was obtained under the conditions of 180 °C for 240 min. In addition, a significant correlation was found between the content of xylose in the solid fraction and the severity factor of treatment. To determine the changes in cellulose crystallinity, the total crystallinity index (TCI) and the lateral order index (LOI) were calculated from the Fourier-transform infrared spectroscopy spectra of cellulose. An increase...
Spruce boards with dimensions of 500 × 500 × 100 mm were thermally loaded during 90 minutes accor... more Spruce boards with dimensions of 500 × 500 × 100 mm were thermally loaded during 90 minutes according the temperature curves PAR1, PAR2 and TNK. In the samples there was determined amount of extractive matters and cellulose. The alterations of degree of polymerisation (DP) and molecular weight distribution (MWD) were analyzed by gel permeation chromatography (GPC) of cellulose tricarbanilates. The amount of cellulose and extractive matters increased and cellulose DP decreased after the thermal loading. The highest decrease of cellulose DP was determined at the temperature curve PAR1 (from 870 to 604), less at the PAR2 (from 845 to 660) and at the least at the TNK (from 890 to 862).
The interaction of water and oak wood is common in outdoor expositions and will remain a probable... more The interaction of water and oak wood is common in outdoor expositions and will remain a probable occurrence in the future. New insights into the recognition of a cell wall saturation limit are presented by a double-weighing method at 20 °C. The cell wall saturation limit, as the property of thermally modified oak wood, is significantly influenced by different treatment temperatures (20, 160, 180, 210 and 240 °C) on a 5% alpha level. A significantly higher equilibrium moisture content was reached by thermally modified oak wood at a temperature of 20 °C and relative humidity of 65% after its equilibrium in the water-in-reservoir. Moreover, the results are used in the treatment of woodchips to produce cellulose or decomposition of thermally modified wood to its basic chemical components. The investigated properties of cellulose revealed its relationship with water. The number of water molecules bonded to a cellulose chain was correlated with other measured compositions: average molecu...
Alterations in the chemical composition of silver fir wood (Abies alba L.) during thermal treatme... more Alterations in the chemical composition of silver fir wood (Abies alba L.) during thermal treatment were investigated. The mass loss, extractives, saccharides, and lignin were determined. In both untreated and heat-treated wood, extractives were determined according to ASTM D1107-96, lignin content according to ASTM D1106-96, and saccharides by high-performance liquid chromatography. During the thermal treatment, mass loss and the chemical composition of the wood were found to change. The extractives content decreased up to 200 °C, and then increased at higher temperatures. The mass loss increased with increasing temperature and time of thermal treatment. A relative increase in lignin content and a decrease in saccharides were observed. The color of the wood was stable at temperatures up to 150 °C when treated up to 1 h. A change in color significantly depends on thermal energy intake above that level. Saccharides, color coordinates L* and b*, lignin, mass loss, temperature, and color change ΔE* strongly vary together. These investigated properties of fir wood set out the boundaries for high-temperature treatment and show potential for utilization of this species.
Correlations between the chemical composition and physical properties of oak wood were studied by... more Correlations between the chemical composition and physical properties of oak wood were studied by correlation analysis. The specimens were produced from thermally treated oak wood at temperatures of 20 °C, 160 °C, 180 °C, 210 °C, and 240 °C. The physical properties were affected by the chemical composition of oak wood. The correlations of equilibrium moisture content (EMC) and oak density at EMC were similar, in accordance with the investigated properties. Oak end hardness was affected by treatment temperature. The depth of indentation significantly affected the hardness. Mass specific heat capacity and effusivity were positively correlated with EMC, sugars, holocellulose, cellulose traits, and ash and negatively affected by total extractives. Thermal diffusivity was slightly affected by treatment temperature.
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Papers by Viera Kučerová