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Advancing climate change is affecting the health and vitality of forests in many parts of the world. Europe is currently facing spruce bark beetle outbreaks, which are most often caused by wind disturbances, hot summers, or lack of rainfall and are having a massive economic impact on the forestry sector. The aim of this research article was to summarize current scientific knowledge about the structure and physical and mechanical properties of wood from bark beetle-attacked trees. Spruce stands are attacked by a number of beetles, of which Ips typographus is the most common and widespread in Central Europe. When attacking a tree, bark beetles introduce ophiostomatoid fungi into the tree, which then have a greater effect on the properties of the wood than the beetles themselves. Fungal hyphae grow through the lumina of wood cells and spread between individual cells through pits. Both white rot and brown rot fungi are associated with enzymatic degradation of lignin or holocellulose, which is subsequently reflected in the change of the physical and mechanical properties of wood. Wood-decay fungi that colonize wood after infestation of a tree with bark beetles can cause significant changes in the structure and properties of the wood, and these changes are predominantly negative, in the form of reducing modulus of rupture, modulus of elasticity, discolouration, or, over time, weight loss. In certain specific examples, a reduction in energy consumption for the production of wood particles from beetle-attacked trees, or an increase in surface free energy due to wood infestation by staining fungi in order to achieve better adhesion of paints or glues, can be evaluated positively.
Štěpán Hýsek; Radim Löwe; Marek Turčáni. What Happens to Wood after a Tree Is Attacked by a Bark Beetle? Forests 2021, 12, 1163 .
AMA StyleŠtěpán Hýsek, Radim Löwe, Marek Turčáni. What Happens to Wood after a Tree Is Attacked by a Bark Beetle? Forests. 2021; 12 (9):1163.
Chicago/Turabian StyleŠtěpán Hýsek; Radim Löwe; Marek Turčáni. 2021. "What Happens to Wood after a Tree Is Attacked by a Bark Beetle?" Forests 12, no. 9: 1163.
The aim of this study was to test caffeine – harmless to health and eco-friendly natural compound – as a potentially effective fungicide and insecticide for wood protection. Caffeine treatment of wood, using simple and cheap long-term dipping technology, was tested against the brown-rot fungus Rhodonia placenta and termite Reticulitermes flavipes. Fungi and insects can cause severe loss of functionality of wooden structures. The current search for of nature-friendly products is understandable in the context of the changing world environment. The experiment with caffeine-treated refractory Norway spruce (Picea abies) wood lasted for 16 weeks against the rot attack according to EN 113, and for 6 weeks against the termite attack according to EN 118. Mass losses of caffeine treated wood samples without ageing, caused by R. placenta and R. flavipes were small, only 1.4% or 0.5%, respectively. Results clearly suggested that caffeine is an alternative to commercial biocides, e.g., to the reference in wood well fixable Bochemit QB, containing boric acid and alkylbenzyldimethylammonium chloride. Caffeine was sensitive for leaching out from wood by water even in the presence of an additional hydrophobic protective layer. Based on the achieved results it is possible to recommend caffeine treatment as an environmentally friendly alternative for wood protection, but only in the interior or outdoor under roof area against termite attack and also against brown-rot fungi. Treatment with caffeine had no negative impact on the compression strength and colour of the spruce wood, while it improved surface wetting important for potentially follow-up coating or adhesive applications.
Kristýna Šimůnková; Ladislav Reinprecht; Jana Nábělková; Štěpán Hýsek; Jiří Kindl; Vlastimil Borůvka; Tereza Lišková; Jan Šobotník; Miloš Pánek. Caffeine – Perspective natural biocide for wood protection against decaying fungi and termites. Journal of Cleaner Production 2021, 304, 127110 .
AMA StyleKristýna Šimůnková, Ladislav Reinprecht, Jana Nábělková, Štěpán Hýsek, Jiří Kindl, Vlastimil Borůvka, Tereza Lišková, Jan Šobotník, Miloš Pánek. Caffeine – Perspective natural biocide for wood protection against decaying fungi and termites. Journal of Cleaner Production. 2021; 304 ():127110.
Chicago/Turabian StyleKristýna Šimůnková; Ladislav Reinprecht; Jana Nábělková; Štěpán Hýsek; Jiří Kindl; Vlastimil Borůvka; Tereza Lišková; Jan Šobotník; Miloš Pánek. 2021. "Caffeine – Perspective natural biocide for wood protection against decaying fungi and termites." Journal of Cleaner Production 304, no. : 127110.
The paper investigated the torrefaction of cones from three tree species: Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies L.), and European larch (Larix decidua Mill.). The objective was to determine the effects of torrefaction temperature on the properties of cones with a view to their further use as a renewable energy source. Torrefaction was conducted at 200, 235, 275, and 320 °C for 60 min under an inert gas atmosphere. Elemental composition, ash content, and lower heating value (LHV) were measured for the original and torrefied samples. Torrefaction performance was evaluated using formulas for solid yield, higher heating value (HHV), HHV enhancement factor, as well as energy yield. Scanning electron microscopy (SEM) was used to assess elemental composition and structural changes at the surface of the torrefied material. For all the studied conifer species, the higher the torrefaction temperature, the greater the carbon and ash content and the higher the LHV (a maximum of 27.6 MJ·kg−1 was recorded for spruce and larch cones torrefied at 320 °C). SEM images showed that an increase in process temperature from 200 to 320 °C led to partial decomposition of the scale surface as a result of lignin degradation. Cone scales from all tree species revealed C, O, N, Mg, K, and Si at the surface (except for pine scales, which did not contain Si). Furthermore, the higher the temperature, the higher the enhancement factor and the lower the energy yield of the torrefied biomass. Under the experimental conditions, spruce cones were characterized by the lowest weight loss, the highest HHV, and the highest energy yield, and so they are deemed the best raw material for torrefaction among the studied species.
Monika Aniszewska; Arkadiusz Gendek; Štěpán Hýsek; Jan Malaťák; Jan Velebil; Barbora Tamelová. Changes in the Composition and Surface Properties of Torrefied Conifer Cones. Materials 2020, 13, 5660 .
AMA StyleMonika Aniszewska, Arkadiusz Gendek, Štěpán Hýsek, Jan Malaťák, Jan Velebil, Barbora Tamelová. Changes in the Composition and Surface Properties of Torrefied Conifer Cones. Materials. 2020; 13 (24):5660.
Chicago/Turabian StyleMonika Aniszewska; Arkadiusz Gendek; Štěpán Hýsek; Jan Malaťák; Jan Velebil; Barbora Tamelová. 2020. "Changes in the Composition and Surface Properties of Torrefied Conifer Cones." Materials 13, no. 24: 5660.
Deforestation is a global threat in the form of the reduction of all of the ecosystem services provided to humans by forest ecosystems. For this reason, this article deals with the protection of forest ecosystem services by searching for a substitute for wood biomass. In recent years, the post-harvest residues of agricultural crops have been used mainly for energy and material uses. If this raw material is to be used industrially in the long term, we must have an idea of its future production. In most studies, predictions of future post-harvest residue productions are resolved in terms of the availability for energy sectors. This paper deals with the total amount of produced post-harvest residues that can be taken from the field; the post-harvest residue production for selected sectors is not subtracted from the overall prediction. Post-harvest residue production was estimated using the residue to product ratio (RPR), wherein the RPR coefficient was calculated for the monitored crops in each year, and the post-harvest residue production was subsequently calculated in each year according to the conversion rate characteristic for each year. The production of two widespread agricultural crops—wheat and rapeseed—was predicted. Linear regression models were used for the estimations. Based on these models, we predict the production of 58.3 million tonnes of post-harvest wheat residues and 22.4 million tonnes of post-harvest rapeseed residues in 2030 in the European Union. In the Czech Republic, we predict the production of 1.8 million tonnes of post-harvest wheat residues and 1.3 million tonnes of post-harvest rapeseed residues. The presented results can be used as the basis for further considerations of the material use of post-harvest residues and for the substitution of wood with these residues.
Petra Hýsková; Štěpán Hýsek; Vilém Jarský. The Utilization of Crop Residues as Forest Protection: Predicting the Production of Wheat and Rapeseed Residues. Sustainability 2020, 12, 5828 .
AMA StylePetra Hýsková, Štěpán Hýsek, Vilém Jarský. The Utilization of Crop Residues as Forest Protection: Predicting the Production of Wheat and Rapeseed Residues. Sustainability. 2020; 12 (14):5828.
Chicago/Turabian StylePetra Hýsková; Štěpán Hýsek; Vilém Jarský. 2020. "The Utilization of Crop Residues as Forest Protection: Predicting the Production of Wheat and Rapeseed Residues." Sustainability 12, no. 14: 5828.
The paper deals with the possibility of using post-harvest crop residues, namely winter wheat straw and winter rapeseed straw for the purpose of producing particleboards. In order to increase particle surface energy, particles were treated with enzymes prior to application of the adhesive; xylanases, pectinase, and a combination of both. The effect of the enzymatic treatment on the properties of the treated particles was monitored and, after the production of the boards, the influence of particle treatment on the mechanical and physical properties of the composites was also monitored. The effect of enzymatic modification on the properties of wheat and rapeseed particles was observed. The enzymes used influenced the particle surface morphology, their surface energy and equilibrium moisture content. Only the combination of pectinase and xylanase (Texazym SER 7) increased the surface energy of wheat surface from 26 mN/m (untreated) to 30 mN/m. The greatest erosion of the surface was achieved by the combination of xylanases and pectinases. After enzymatic treatment both wheat and rapeseed straw exhibited higher equilibrium moisture content. The increase of moisture of wheat straw was from 11.9 %–13.2 % and of rapeseed straw from 12.4 %–13.44 %. Although the selected enzymes had an effect on the properties of the particles, the effect of the enzymatic treatment on the equilibrium moisture, the internal bond strength and the bending characteristics of the produced particleboards were not observed. Produced boards reached low mechanical properties, internal bond strength reached values form to 61–99 mN/mm2.
Petra Hýsková; Štěpán Hýsek; Ondřej Schönfelder; Přemysl Šedivka; Martin Lexa; Vilém Jarský. Utilization of agricultural rests: Straw-based composite panels made from enzymatic modified wheat and rapeseed straw. Industrial Crops and Products 2019, 144, 112067 .
AMA StylePetra Hýsková, Štěpán Hýsek, Ondřej Schönfelder, Přemysl Šedivka, Martin Lexa, Vilém Jarský. Utilization of agricultural rests: Straw-based composite panels made from enzymatic modified wheat and rapeseed straw. Industrial Crops and Products. 2019; 144 ():112067.
Chicago/Turabian StylePetra Hýsková; Štěpán Hýsek; Ondřej Schönfelder; Přemysl Šedivka; Martin Lexa; Vilém Jarský. 2019. "Utilization of agricultural rests: Straw-based composite panels made from enzymatic modified wheat and rapeseed straw." Industrial Crops and Products 144, no. : 112067.
The submitted paper deals with the physical and mechanical properties of geopolymer composite materials reinforced with natural fibres. For this study, we aimed to develop a geopolymer composite reinforced with long flax fibres, which were implemented in the geopolymer in the form of a nonwoven fabric that reinforced the structure of the geopolymer over the entire thickness of the board. In order to compare the properties of the developed composite with natural fibres, a geopolymer without fibres and a geopolymer reinforced with basalt fibres were also produced. The monitored mechanical properties were impact bending, bending strength and compressive strength. Differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR) and microscopic analysis were also carried out. The results clearly showed the positive effect of the addition of natural fibres on impact bending and bending strength. However, the addition of natural fibres in the form of a nonwoven fabric significantly increased the variability of the properties of the developed composites. In addition, a different pattern of joint failure was noted between geopolymer reinforced with flax fibres and geopolymer reinforced with basalt fibres.
Miroslav Frydrych; Štěpán Hýsek; Ludmila Fridrichová; Su Le Van; Miroslav Herclík; Miroslava Pechočiaková; Hiep Le Chi; Petr Louda. Impact of Flax and Basalt Fibre Reinforcement on Selected Properties of Geopolymer Composites. Sustainability 2019, 12, 118 .
AMA StyleMiroslav Frydrych, Štěpán Hýsek, Ludmila Fridrichová, Su Le Van, Miroslav Herclík, Miroslava Pechočiaková, Hiep Le Chi, Petr Louda. Impact of Flax and Basalt Fibre Reinforcement on Selected Properties of Geopolymer Composites. Sustainability. 2019; 12 (1):118.
Chicago/Turabian StyleMiroslav Frydrych; Štěpán Hýsek; Ludmila Fridrichová; Su Le Van; Miroslav Herclík; Miroslava Pechočiaková; Hiep Le Chi; Petr Louda. 2019. "Impact of Flax and Basalt Fibre Reinforcement on Selected Properties of Geopolymer Composites." Sustainability 12, no. 1: 118.
Changes in surface material characteristics can significantly affect the adhesion and overall life of coatings on wood. In order to increase the durability of transparent exterior coatings, it is possible to use the surface modification of wood with UV-stabilizing substances. In this work, selected types of surface modifications using benzotriazoles, HALS, ZnO and TiO2 nanoparticles, and their combinations were applied to oak wood (Quercus robur, L.). On such modified surfaces, the surface free energy, roughness, and contact wetting angle with three selected types of exterior transparent coatings were subsequently determined. An oil-based coating, waterborne acrylic thick layer coating, and thin-layer synthetic coating were tested and interaction with the aforementioned surface modifications was investigated after 6 weeks of accelerated artificial weathering. The results of changes in the initially measured surface characteristics of the modified oak wood were compared to the real results of degradation of coatings after artificial accelerated weathering. The positive effect of surface modification, in particular the mixture of benzotriazoles, HALS, and ZnO nanoparticles on all kinds of coatings was proven, and the best results were observed in thick-film waterborne acrylic coating. The changes in the measured surface characteristics corresponded to the observed durability of the coatings only when measured by wetting using drops of the tested coatings.
Miloš Pánek; Štěpán Hýsek; Ondřej Dvořák; Aleš Zeidler; Eliška Oberhofnerová; Kristýna Šimůnková; Přemysl Šedivka. Durability of the Exterior Transparent Coatings on Nano-Photostabilized English Oak Wood and Possibility of Its Prediction before Artificial Accelerated Weathering. Nanomaterials 2019, 9, 1568 .
AMA StyleMiloš Pánek, Štěpán Hýsek, Ondřej Dvořák, Aleš Zeidler, Eliška Oberhofnerová, Kristýna Šimůnková, Přemysl Šedivka. Durability of the Exterior Transparent Coatings on Nano-Photostabilized English Oak Wood and Possibility of Its Prediction before Artificial Accelerated Weathering. Nanomaterials. 2019; 9 (11):1568.
Chicago/Turabian StyleMiloš Pánek; Štěpán Hýsek; Ondřej Dvořák; Aleš Zeidler; Eliška Oberhofnerová; Kristýna Šimůnková; Přemysl Šedivka. 2019. "Durability of the Exterior Transparent Coatings on Nano-Photostabilized English Oak Wood and Possibility of Its Prediction before Artificial Accelerated Weathering." Nanomaterials 9, no. 11: 1568.
Totora (Schoenoplectus californicus. C.A. Mey, Sojak) is an annual-cycled macrophyte from the Cyperaceae family that has been used by indigenous people of the Americas for more than 500 years to produce a wide range of objects from handicrafts to boats and huts. In this study, the hot-pressing process was applied to produce boards from totora particles without added adhesives. First, the physical and mechanical properties of totora binder-free boards are described. Secondly, several factors that influence the properties of totora boards are taken into account. However, is it worth it to produce such boards? In this paper, the reasonability of potential production of these boards is considered from a complex point of view. Although totora shows several benefits such as its fast-growth rate, high dry matter productivity, and potential environmental benefits; the water uptake (92–341%), thickness swelling (75–227%) and internal bonding (18–85 kPa) of the binderless boards made with the parameters described in this study could not comply with current standards. Further research on treatments or different production parameters can lead to better properties.
Petra Hýsková; Milan Gaff; Juan Fernando Hidalgo-Cordero; Štěpán Hýsek. Composite materials from totora (Schoenoplectus californicus. C.A. Mey, Sojak): Is it worth it? Composite Structures 2019, 232, 111572 .
AMA StylePetra Hýsková, Milan Gaff, Juan Fernando Hidalgo-Cordero, Štěpán Hýsek. Composite materials from totora (Schoenoplectus californicus. C.A. Mey, Sojak): Is it worth it? Composite Structures. 2019; 232 ():111572.
Chicago/Turabian StylePetra Hýsková; Milan Gaff; Juan Fernando Hidalgo-Cordero; Štěpán Hýsek. 2019. "Composite materials from totora (Schoenoplectus californicus. C.A. Mey, Sojak): Is it worth it?" Composite Structures 232, no. : 111572.
This study provides a solution for the utilization of two waste materials, namely the residues of soft polyurethane foam from the production of mattresses and winter wheat husks. Thermal insulation panels with a nominal density of 50–150 kg/m3, bonded one-component moisture curing polyurethane adhesive, were developed, and the effect of the ratio between recycled polyurethane foam and winter wheat husk on internal bond strength, compressive stress at 10% strain, water uptake, coefficient of thermal conductivity, and volumetric heat capacity was observed. The developed composite materials make use of the very good thermal insulation properties of the two input waste materials, and the coefficient of thermal conductivity of the resulting boards achieves excellent values, namely 0.0418–0.0574 W/(m.K). The developed boards can be used as thermal insulation in the structures of environmentally friendly buildings.
Štěpán Hýsek; Pavel Neuberger; Adam Sikora; Ondřej Schönfelder; Gianluca DiTommaso. Waste Utilization: Insulation Panel from Recycled Polyurethane Particles and Wheat Husks. Materials 2019, 12, 3075 .
AMA StyleŠtěpán Hýsek, Pavel Neuberger, Adam Sikora, Ondřej Schönfelder, Gianluca DiTommaso. Waste Utilization: Insulation Panel from Recycled Polyurethane Particles and Wheat Husks. Materials. 2019; 12 (19):3075.
Chicago/Turabian StyleŠtěpán Hýsek; Pavel Neuberger; Adam Sikora; Ondřej Schönfelder; Gianluca DiTommaso. 2019. "Waste Utilization: Insulation Panel from Recycled Polyurethane Particles and Wheat Husks." Materials 12, no. 19: 3075.
This paper deals with the development and characteristics of the properties of a permeable water-resistant heat insulation panel based on recycled materials. The insulation panel consists of a thermal insulation core of recycled soft polyurethane foam and winter wheat husk, a layer of geopolymer that gives the entire sandwich composite strength and fire resistance, and a nanofibrous membrane that permits water vapor permeability, but not water in liquid form. The observed properties are the thermal conductivity coefficient, volumetric heat capacity, fire resistance, resistance to long-term exposure of a water column, and the tensile strength perpendicular to the plane of the board. The results showed that while the addition of husk to the thermal insulation core does not significantly impair its thermal insulation properties, the tensile strength perpendicular to the plane of these boards was impaired by the addition of husk. The geopolymer layer increased the fire resistance of the panel for up to 13 min, and the implementation of the nanofibrous membrane resulted in a water flow of 154 cm2 in the amount of 486 g of water per 24 h at a water column height of 0.8 m.
Štěpán Hýsek; Miroslav Frydrych; Miroslav Herclík; Ludmila Fridrichová; Petr Louda; Roman Knížek; Su Le Van; Hiep Le Chi. Permeable Water-Resistant Heat Insulation Panel Based on Recycled Materials and Its Physical and Mechanical Properties. Molecules 2019, 24, 3300 .
AMA StyleŠtěpán Hýsek, Miroslav Frydrych, Miroslav Herclík, Ludmila Fridrichová, Petr Louda, Roman Knížek, Su Le Van, Hiep Le Chi. Permeable Water-Resistant Heat Insulation Panel Based on Recycled Materials and Its Physical and Mechanical Properties. Molecules. 2019; 24 (18):3300.
Chicago/Turabian StyleŠtěpán Hýsek; Miroslav Frydrych; Miroslav Herclík; Ludmila Fridrichová; Petr Louda; Roman Knížek; Su Le Van; Hiep Le Chi. 2019. "Permeable Water-Resistant Heat Insulation Panel Based on Recycled Materials and Its Physical and Mechanical Properties." Molecules 24, no. 18: 3300.
Post-harvest crop residues are an interesting raw material for the production of composite materials. However, their surface often contains waxy and siliceous substances, which can cause adhesion problems. Therefore, various surface pre-treatment methods have been developed to increase the surface tension of these particles and hence to improve adhesive adhesion. The influence of hydrothermal, chemical, plasma and enzymatic treatment was investigated. The aim of the paper is to evaluate the effect of pre-treatments of post-harvest crop residues on the nature of joint failure and adhesive dispersion on the particles. The evaluation is based on microscopic analysis of particles obtained from the rupture area after internal bonding tests. The nature of bond failure and adhesive dispersion on the particle surface is evaluated. The results show a clear influence of material pre-treatment on the failure bond of the bond and, to a large extent, correlate with the mechanical properties of composites published in previous studies. The most suitable treatment appears to be a plasma treatment at a properly adjusted intensity. Conversely, the unsuitable treatment was alkaline, which, although it increased adhesion, deteriorated the overall mechanical properties. Hydrothermal treatment could be also considered as an industrially suitable method.
Štěpán Hýsek; Jaroslav Čermák; Martin Lexa. Influence of Lignocellulosic Waste Pre-Treatment on the Characteristics of Bond Rupture. Sustainability 2019, 11, 4784 .
AMA StyleŠtěpán Hýsek, Jaroslav Čermák, Martin Lexa. Influence of Lignocellulosic Waste Pre-Treatment on the Characteristics of Bond Rupture. Sustainability. 2019; 11 (17):4784.
Chicago/Turabian StyleŠtěpán Hýsek; Jaroslav Čermák; Martin Lexa. 2019. "Influence of Lignocellulosic Waste Pre-Treatment on the Characteristics of Bond Rupture." Sustainability 11, no. 17: 4784.
The development of composite materials from alternative raw materials, and the design of their properties for the intended purpose is an integral part of the rational management of raw materials and waste recycling. The submitted paper comprehensively assesses the physical and mechanical properties of sandwich composite material made from particles of winter rapeseed stalks, geopolymer and reinforcing basalt lattices. The developed composite panel is designed for use as a filler in constructions (building or building joinery). The observed properties were: bending characteristics, internal bonding, thermal conductivity coefficient and combustion characteristics. The results showed that the density of the particleboard has a significant effect on the resulting mechanical properties of the entire sandwich panel. On the contrary, the density of the second layer of the sandwich panel, geopolymer, did not have the same influence on its mechanical properties as the density of the particleboard. The basalt fibre reinforcement lattice positively affected the mechanical properties of sandwich composites only if it was sufficiently embedded in the structure of the particle board. All of the manufactured sandwich composites resisted flame for more than 13 min and the fire resistance was positively affected by the density of the geopolymer layer.
Štěpán Hýsek; Miroslav Frydrych; Miroslav Herclík; Petr Louda; Ludmila Fridrichová; Su Le Van; Hiep Le Chi. Fire-Resistant Sandwich-Structured Composite Material Based on Alternative Materials and Its Physical and Mechanical Properties. Materials 2019, 12, 1432 .
AMA StyleŠtěpán Hýsek, Miroslav Frydrych, Miroslav Herclík, Petr Louda, Ludmila Fridrichová, Su Le Van, Hiep Le Chi. Fire-Resistant Sandwich-Structured Composite Material Based on Alternative Materials and Its Physical and Mechanical Properties. Materials. 2019; 12 (9):1432.
Chicago/Turabian StyleŠtěpán Hýsek; Miroslav Frydrych; Miroslav Herclík; Petr Louda; Ludmila Fridrichová; Su Le Van; Hiep Le Chi. 2019. "Fire-Resistant Sandwich-Structured Composite Material Based on Alternative Materials and Its Physical and Mechanical Properties." Materials 12, no. 9: 1432.
Colour changes and associated wood degradation in exterior and interior applications influenced by ultraviolet (UV) and visible radiation (VIS) decreases the aesthetic value of the products and shortens the overall life of transparent coatings. The aim of the paper is to achieve colour stabilization of oak, larch, Douglas fir and spruce heartwood via surface treatment with UV stabilizers, hindered amine light stabilizers (HALS), nanoparticles TiO2, ZnO, and mixtures thereof, during exposure to UV and VIS radiation. Colour changes were evaluated during accelerated artificial ageing testing in Xenotest. The distinctly individual character of colour changes in surface treatments due to the underlying wood species was confirmed. A synergistic effect was found when using a combination of active substances compared to substances used individually. The mixture of benzotriazoles with HALS (Tinuvin 5151) in combination with TiO2 and ZnO nanoparticles was confirmed as one of the most effective treatments for colour stabilization of wood due to UV and VIS spectrums.
Miloš Pánek; Eliška Oberhofnerová; Štěpán Hýsek; Přemysl Šedivka; Aleš Zeidler. Colour Stabilization of Oak, Spruce, Larch and Douglas Fir Heartwood Treated with Mixtures of Nanoparticle Dispersions and UV-Stabilizers after Exposure to UV and VIS-Radiation. Materials 2018, 11, 1653 .
AMA StyleMiloš Pánek, Eliška Oberhofnerová, Štěpán Hýsek, Přemysl Šedivka, Aleš Zeidler. Colour Stabilization of Oak, Spruce, Larch and Douglas Fir Heartwood Treated with Mixtures of Nanoparticle Dispersions and UV-Stabilizers after Exposure to UV and VIS-Radiation. Materials. 2018; 11 (9):1653.
Chicago/Turabian StyleMiloš Pánek; Eliška Oberhofnerová; Štěpán Hýsek; Přemysl Šedivka; Aleš Zeidler. 2018. "Colour Stabilization of Oak, Spruce, Larch and Douglas Fir Heartwood Treated with Mixtures of Nanoparticle Dispersions and UV-Stabilizers after Exposure to UV and VIS-Radiation." Materials 11, no. 9: 1653.
The effect of different types of winter wheat husks treatments (alkaline, hydrothermal and plasma treatment) on the properties of the particle material, as well as on composite materials made from such pre-treated husks, was studied. After pre-treatment, the surface energy, equilibrium moisture content, surface morphology using SEM, elemental content on the surface and the fluorescence life time (FLIM) of husks were estimated, as well as the IR spectra (FTIR) of pre-treated husks. Boards with target density of 450 kg/m3 were produced using urea-formaldehyde resin (resination 9%) and the equilibrium moisture content, thickness swelling, vertical density profile, internal bonding, bending strength and insulation properties of boards were examined. Modification in 2% sodium hydroxide solution caused noticeable erosion of husks resulting in higher lignin content, higher equilibrium moisture of husks and consequently higher thickness swelling of boards made from pre-treated husks and lower mechanical properties of those boards. Both hydrothermal (boiling in water) and plasma treatment (air plasma at atmospheric pressure, jet system of application) resulted in the desired effect in terms of an increase in the surface energy of husks, decrease of husk equilibrium moisture content and increase of mechanical properties of boards. All of the manufactured boards exhibited low thermal conductivity that ranged from 0.0714 W/(mK) to 0.0783 W/(mK).
Štěpán Hýsek; Milan Podlena; Henry Bartsch; Christoph Wenderdel; Martin Bohm. Effect of wheat husk surface pre-treatment on the properties of husk-based composite materials. Industrial Crops and Products 2018, 125, 105 -113.
AMA StyleŠtěpán Hýsek, Milan Podlena, Henry Bartsch, Christoph Wenderdel, Martin Bohm. Effect of wheat husk surface pre-treatment on the properties of husk-based composite materials. Industrial Crops and Products. 2018; 125 ():105-113.
Chicago/Turabian StyleŠtěpán Hýsek; Milan Podlena; Henry Bartsch; Christoph Wenderdel; Martin Bohm. 2018. "Effect of wheat husk surface pre-treatment on the properties of husk-based composite materials." Industrial Crops and Products 125, no. : 105-113.
Using crop residues for the production of composite materials is increasingly substantiated due to the increasing lack of quality wood pulp in the wood processing industry. Crop residues of winter rapeseed, the stems of which are produced in the amount of 42 million tons each year in the European Union and have not yet been exploited for products with high added value, are a potentially interesting raw material for the manufacture of composite materials. If materials based on annual plants are to fully replace the use of materials based on wood, glass, metal or plastic, it is necessary to know their characteristics. In the wood processing industry most of the attention is focused on physical properties, which have an immediate effect on the mechanical properties. Knowledge of the effect of the interaction of several factors (feedstock, technological parameters) on characteristics describing the elastic properties of the material is this article's contribution. Knowledge of the interaction of these factors gives the manufacturer instructions for modifying the input parameters with the aim of producing a material with specific mechanical properties appropriate for the intended use.The article deals with the mechanical properties of composite materials manufactured from winter rapeseed crop residues subjected to bending. The results of the research describe the effect of surface modification (chemical or hydrothermal) of particles on the bending characteristics measured within the elastic region: bending modulus of elasticity „MOE“, elastic potential „EP“, stress at the limit of proportionality „LOP“. Thanks to the acquired knowledge, we can specifically modify the properties of composite material for the intended use in the future.
Štepán Hýsek; Milan Gaff; Adam Sikora; Marián Babiak. New composite material based on winter rapeseed and his elasticity properties as a function of selected factors. Composites Part B: Engineering 2018, 153, 108 -116.
AMA StyleŠtepán Hýsek, Milan Gaff, Adam Sikora, Marián Babiak. New composite material based on winter rapeseed and his elasticity properties as a function of selected factors. Composites Part B: Engineering. 2018; 153 ():108-116.
Chicago/Turabian StyleŠtepán Hýsek; Milan Gaff; Adam Sikora; Marián Babiak. 2018. "New composite material based on winter rapeseed and his elasticity properties as a function of selected factors." Composites Part B: Engineering 153, no. : 108-116.
Permeability of coatings for water and water vapor is an important factor in their wood protective function. In this study, the permeability of coatings in terms of liquid water and water vapor absorption and desorption was measured based on different parts of the standard EN 927. This study evaluated the permeability of commercial coating systems and ascertained effects of coating layering on the coating permeability. For this measurement, six different waterborne acrylate dispersions were used as paint on spruce test samples. The results clearly revealed that liquid water and water vapor uptake were affected by coating film thickness, number of coats, and coating composition (producer). It was ascertained that the type of coating pigmentation affected water absorption of coatings and that with a constant coating film thickness, the number of coats affected water vapor absorption and desorption, but not water absorption. Furthermore, it was observed that the number of coats affected the correlation between the coating film thickness and water vapor absorption and desorption. The values for water vapor absorption were much higher than for liquid water absorption and, unlike the water vapor absorption rate, the water vapor desorption rate was approximately 50% lower.
Štěpán Hýsek; Hakan Fidan; Miloš Pánek; Martin Böhm; Kamil Trgala. WATER PERMEABILITY OF EXTERIOR WOOD COATINGS: WATERBORNE ACRYLATE DISPERSIONS FOR WINDOWS. Journal of Green Building 2018, 13, 1 -16.
AMA StyleŠtěpán Hýsek, Hakan Fidan, Miloš Pánek, Martin Böhm, Kamil Trgala. WATER PERMEABILITY OF EXTERIOR WOOD COATINGS: WATERBORNE ACRYLATE DISPERSIONS FOR WINDOWS. Journal of Green Building. 2018; 13 (3):1-16.
Chicago/Turabian StyleŠtěpán Hýsek; Hakan Fidan; Miloš Pánek; Martin Böhm; Kamil Trgala. 2018. "WATER PERMEABILITY OF EXTERIOR WOOD COATINGS: WATERBORNE ACRYLATE DISPERSIONS FOR WINDOWS." Journal of Green Building 13, no. 3: 1-16.
Fillers can greatly affect the properties of adhesives, and this research aimed at enhancing the performance of adhesives by using different concentrations of fillers. This paper describes the influence of using recycled polyurethane particles (powder of particle size from 10 µm to 50 µm) as a filler on some properties of polyurethane adhesives for the gluing of wood. Two kinds of one-component, moisture-curing polyurethane adhesives were used. The observed properties were the contact angle between the wood and adhesive droplet, and the strength of bonded joints (shear strength). From the results, it was concluded that the contact angle increased with an increase in filler (in the entire observed range from 0% to 15% filler). The content of filler also affected the strength of bonded joints and their thermal stability. The strength of bonded joints decreased with an increase in filler content when samples were conditioned in cold water. However, the strength of bonded joints increased with an increase in filler content when samples were boiled in water.
Štepán Hysek; Přemysl Šedivka; Martin Böhm; Ondřej Schönfelder; Rudolf Beran. Influence of Using Recycled Polyurethane Particles as a Filler on Properties of Polyurethane Adhesives for Gluing of Wood. BioResources 2018, 13, 2592-2601 .
AMA StyleŠtepán Hysek, Přemysl Šedivka, Martin Böhm, Ondřej Schönfelder, Rudolf Beran. Influence of Using Recycled Polyurethane Particles as a Filler on Properties of Polyurethane Adhesives for Gluing of Wood. BioResources. 2018; 13 (2):2592-2601.
Chicago/Turabian StyleŠtepán Hysek; Přemysl Šedivka; Martin Böhm; Ondřej Schönfelder; Rudolf Beran. 2018. "Influence of Using Recycled Polyurethane Particles as a Filler on Properties of Polyurethane Adhesives for Gluing of Wood." BioResources 13, no. 2: 2592-2601.
The effects of ultraviolet light irradiation and water spray and temperature cycling on the color stability of waterborne coating systems on spruce were investigated. The test samples were treated with three coating systems (white and brown pigmented acrylate waterborne coatings systems with different layering) from six producers. The artificial weathering was carried out based on standardized (504 h) and increased weathering parameters (504 h). Thirty cycles of temperature changes were performed. Discoloration suggesting the rate of degradation process and color stability was measured by a spectrophotometer in L*a*b* color space. The results showed greater color stability of white coating systems during both experiments. The producer of acrylate coatings with iodopropynyl butyl carbamate and permethrin as biocides and benzotriazole, silicon dioxide and methylsiloxane as additives was characterized by the best coatings performance. The most sensitive color parameter to describe the surface quality as a result of irradiation and water spray has proven to be a change of lightness. A tendency towards degradation with increasing lightness was observed during weathering. The effect of temperature itself on color change was minimal. Scanning electron microscopy and energy dispersive spectroscopy revealed microscopic changes of coatings caused by artificial weathering.
Eliška Oberhofnerová; Štěpán Hýsek; Miloš Pánek; Martin Bohm. Effect of artificial weathering and temperature cycling on the performance of coating systems used for wooden windows. Journal of Coatings Technology and Research 2018, 15, 851 -865.
AMA StyleEliška Oberhofnerová, Štěpán Hýsek, Miloš Pánek, Martin Bohm. Effect of artificial weathering and temperature cycling on the performance of coating systems used for wooden windows. Journal of Coatings Technology and Research. 2018; 15 (4):851-865.
Chicago/Turabian StyleEliška Oberhofnerová; Štěpán Hýsek; Miloš Pánek; Martin Bohm. 2018. "Effect of artificial weathering and temperature cycling on the performance of coating systems used for wooden windows." Journal of Coatings Technology and Research 15, no. 4: 851-865.
The purpose of this study was to evaluate the impact of glue line thickness on joint strength properties, while using two types of PVAc adhesive (i,e. one-component Rhenocell 3W, 4B Plus, resistivity class D3, and two-component Protovil VP244/2C, resistivity class D4) belonging to the group of thermoplastic adhesives intended for non-construction joints. Joint strength testing was carried out using the transverse tensile test for estimation of the joint strength method. It was proven that if specimens were conditioned for 7 days at 20 ± 2°C and a relative air humidity of 65 ± 5%, when testing one-component Rhenocell 3W, 4B Plus (D3) adhesive, increasing thickness of the glue line results in falling strength of the bonded joint. When testing the two-component Protovil VP244/2C (D4) adhesive, increasing thickness of the glue line always results in increasing joint strength, even under conditions when water is directly affecting the joint, or under increased temperatures.
Jan Bomba; Přemysl Šedivka; Štěpán Hýsek; Jiří Fáber; Eliška Oberhofnerová. Influence of Glue Line Thickness on the Strength of Joints Bonded with PVAc Adhesives. Forest Products Journal 2017, 1 .
AMA StyleJan Bomba, Přemysl Šedivka, Štěpán Hýsek, Jiří Fáber, Eliška Oberhofnerová. Influence of Glue Line Thickness on the Strength of Joints Bonded with PVAc Adhesives. Forest Products Journal. 2017; ():1.
Chicago/Turabian StyleJan Bomba; Přemysl Šedivka; Štěpán Hýsek; Jiří Fáber; Eliška Oberhofnerová. 2017. "Influence of Glue Line Thickness on the Strength of Joints Bonded with PVAc Adhesives." Forest Products Journal , no. : 1.
Material alternatives to wood, such as rape straw, are needed for the production of composite materials. This study performed an analysis of rape straw as a composite material source for production. There were three types of rape straw particle modification: untreated particles as reference variant, boiling in water, and soaking in sodium hydroxide (NaOH) solution. The pH and calorific value were highest for the variant soaked in NaOH. The total elemental content and the elements on the rape straw surface varied between variants. The modification method chosen influenced the pH, calorific value, elemental composition, and contact angle.
Tereza Castkova; Štepán Hysek; Adam Sikora; Ondřej Schönfelder; Martin Böhm. Chemical and Physical Parameters of Different Modifications of Rape Straw (Brassica napus L.). BioResources 2017, 13, 104-114 .
AMA StyleTereza Castkova, Štepán Hysek, Adam Sikora, Ondřej Schönfelder, Martin Böhm. Chemical and Physical Parameters of Different Modifications of Rape Straw (Brassica napus L.). BioResources. 2017; 13 (1):104-114.
Chicago/Turabian StyleTereza Castkova; Štepán Hysek; Adam Sikora; Ondřej Schönfelder; Martin Böhm. 2017. "Chemical and Physical Parameters of Different Modifications of Rape Straw (Brassica napus L.)." BioResources 13, no. 1: 104-114.