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  • 1.
    Sun, Ying
    et al.
    University of Texas at Austin, Austin, USA.
    Gu, Lianhong
    Oak Ridge National Laboratory, USA.
    Dickinson, Robert E.
    University of Texas at Austin, USA.
    Pallardy, Stephen G.
    University of Missouri, USA.
    Baker, John
    University of Minnesota, USA.
    Cao, Yonghui
    Chinese Academy of Forestry, China.
    Damatta, Fábio Murilo
    Universidade Federal de Viçosa, Brazil.
    Dong, Xuejun
    North Dakota State University, USA.
    Ellsworth, David
    University of Western Sydney, Australia.
    Van Goethem, Davina
    University of Antwerp, Belgium.
    Jensen, Anna M.
    Oak Ridge National Laboratory, USA.
    Law, Beverly E.
    Oregon State University, USA.
    Loos, Rodolfo
    Technology Center, Fibria Celulose S.A, Aracruz, Brazil.
    Martins, Samuel C. Vitor
    Universidade Federal de Viçosa, Brazil.
    Norby, Richard J.
    Oak Ridge National Laboratory, USA.
    Warren, Jeffrey M.
    Oak Ridge National Laboratory, USA.
    Weston, David
    Oak Ridge National Laboratory, USA.
    Winter, Klaus
    Smithsonian Tropical Research Institute, Republic of Panama.
    Asymmetrical effects of mesophyll conductance on fundamental photosynthetic parameters and their relationships estimated from leaf gas exchange measurements2014Ingår i: Plant, Cell and Environment, ISSN 0140-7791, E-ISSN 1365-3040, Vol. 37, nr 4, 978-994 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Worldwide measurements of nearly 130 C3 species covering all major plant functional types are analysed in conjunction with model simulations to determine the effects of mesophyll conductance (gm) on photosynthetic parameters and their relationships estimated fromA/Ci curves. We find that an assumption of infinite gm results in up to 75% underestimation for maximum carboxylation rate Vcmax, 60% for maximum electron transport rate Jmax, and 40% for triose phosphate utilization rate TuVcmax is most sensitive, Jmax is less sensitive, and Tuhas the least sensitivity to the variation of gm. Because of this asymmetrical effect of gm, the ratios of Jmax to VcmaxTu to Vcmax and Tu toJmax are all overestimated. An infinite gm assumption also limits the freedom of variation of estimated parameters and artificially constrains parameter relationships to stronger shapes. These findings suggest the importance of quantifying gm for understanding in situphotosynthetic machinery functioning. We show that a nonzero resistance to CO2 movement in chloroplasts has small effects on estimated parameters. A non-linear function with gm as input is developed to convert the parameters estimated under an assumption of infinite gm to proper values. This function will facilitate gm representation in global carbon cycle models.

  • 2.
    Poudel, Bishnu Chandra
    Mid Sweden University.
    Carbon Balance Implications of Forest Biomass Production Potential2014Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Forests in boreal and temperate forest-ecosystems have importance for carbonbalance since they sequester large amount of atmospheric carbon by uptake ofcarbon-dioxide during photosynthesis, and transfer and store carbon in the forestecosystem. Forest material can be used for bio-fuel purposes and substitute fossilfuels, and supply wood products, which can replace carbon-and-energy-intensivematerials. Therefore it is vital to consider the role of forests regarding today´s aimto mitigate climate change. This thesis assess (i) how climate change affects futureforest carbon balance, (ii) the importance of different strategies for forestmanagement systems, and biomass production for the carbon balance, (iii) how theuse of forest production affect the total carbon balance in a lifecycle perspective,and (iv) how the Swedish carbon balance is affected from the standpoint of boththe actual use of forest raw material within Sweden and what Swedish forestryexports. The analysis was made mainly in a long-term perspective (60-300 years) toillustrate the importance of temporal and also the spatial perspective, as theanalysis includes stand level, landscape level, and national level.

    In this thesis, forestry was considered a system. All activities, from forestregeneration to end use of forest products, were entities of this system. In theevaluation, made from a systems perspective, we used life-cycle analysis toestimate carbon stock in different system flows. Different forest managementsystems and forest production were integrated in the analyses. Different forestmanagement scenarios were designed for the Swedish forest management incombination with the effect of future climate change; (i) intensive forest practiceaiming at increased growth, (ii) increased forest set-aside areas, changes in forestmanagement systems for biomass production, and (iii) how the use of forestproducts affect the total carbon balance (construction material, bioenergy and otherdomestic use).

    The results showed that future climate changes and intensive forest managementwith increased production could increase the biomass production and the potentialuse of forest raw material. This has a positive effect on carbon stock change in theforest biomass, litter production and below ground carbon stock and help reducingcarbon-dioxide emissions. Increased forest set-aside areas can increase the shorttermcarbon stock in forest ecosystems, but will reduce the total long-term carbonbalance. The net carbon balance for clear-cut forestry did not differ significantlyfrom continuous-cover forestry, but was rather a question of level of growth. Mostimportant, in the long term, was according to our analysis, how forest raw materialis used. Present Swedish forestry and use of forest raw material, both withinSweden and abroad, reduce carbon-dioxide emissions and mitigate climate change.The positive effect for the total carbon balance and climate benefit mostly takeplace abroad, due to the Swedish high level of export of wood products and thehigher substitution effects achieved outside Swedish borders. One strategy is toincrease production, harvest and use Swedish forest raw material to replace morecarbon intensive material, which can contribute to significant emission reduction.Carbon-dioxide mitigation, as a result of present Swedish forestry, was shown tobe almost of the same level as the total yearly emission of greenhouse gases. Thetotal carbon benefit would increase if the biomass production and felling increasedand if Swedish wood products replaced carbon intensive materials.

    This thesis shows also that, by changing forest management, increase thegrowth and the use of forest raw material and export of forest material we cancontribute to even larger climate benefits. In a long-term perspective, thesubstitution effects and replacement of carbon-and energy-intensive materials areof greater significance than carbon storage effects in forests. A more productionoriented forestry needs to make balances and increase the prerequisite forbiological diversity, improve recreation possibilities, and protect sensitive landareas and watersheds.

    Climate benefits, from Swedish forestry, are highly dependent on policydecision-making and how that can steer the direction for the Swedish forestry.

  • 3.
    Svensson, Henric
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM).
    Characterization, toxicity and treatment of wood leachate generated outdoors by the wood-based industry2014Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [sv]

    Trä är ett naturligt råmaterial som knappast anses vara en risk för miljön. Däremot har hanteringen av trämaterial i industriell skala visat sig ha negativ inverkan på vattendrag. De flesta utredningar avseende vattenföroreningar inom träbaserade industrier har fokuserat på stora industrier med stor vattenförbrukning så som massa- och pappersbruk. Lakvatten som alstras vid kontakten mellan vatten och trä innehåller höga halter av organiska ämnen som är potentiellt farliga för vattendrag. Målet med denna avhandling är att få kunskap om ovanstående miljöproblem och möjlig behandlingar av dessa. Förorenat lakvatten skapas av industrier, där stora mängder timmer och sågspån är placerade utomhus och utsätts för regn och bevattning, såsom inom trägolv och bioenergisektorn. Man har funnit att lakning från olika träslag ger olika sammansättningar på lakvattnet, där lakvatten från ek har den högsta halten av föroreningar följt av furu. Denna undersökning visar att ek har potential att laka ut tio gånger så mycket polyfenoler jämfört med andra undersökta arter (tall, bok och lönn). Dessutom har lakvatten från ek den lägsta andelen av biologisk syreförbrukning efter 7dagar per kemisk syreförbrukning (0,12), vilket tyder på ett potentiellt problem med den biologiska nedbrytningen av detta lakvatten. Man har även påvisat att lakvattnet från trä är potentiellt giftigt för akvatiska organismer.

    Studier för att försöka minska miljöpåverkan av lakvatten från denna trädsort gjordes i pilotskala inom ramen för denna avhandling. Dessa studier visade bland annat på möjligheterna att använda sig av våtmarker som reningsmetod, där växter och luftning påverkar hur bra en våtmark fungerar. Men den viktigaste faktorn var den ökade uppehållstiden som vattnet får i våtmarken. Utöver studier av våtmarker har också ett filtermaterial studerats, filtret bestod av en blandning av torv och aska, som användes för att absorbera en specifik kemisk grupp i lakvattnet (polyfenoler). I en tredje typ av behandlingsprocess visade det sig också att polyfenoler effektivt kan brytas ned av ozon.

  • 4.
    Kielmann, B
    et al.
    Georg-August-University Göttingen, Germany.
    Adamopoulos, Stergios
    Georg-August-University Göttingen, Germany ; Technological Educational Institute of Thessaly, Greece.
    Militz, H
    Georg-August-University Göttingen, Germany.
    Mai, C
    Georg-August-University Göttingen, Germany.
    Decay resistance of ash, beech and maple wood modified with N-methylol melamine and a metal complex dye2014Ingår i: International Biodeterioration & Biodegradation, ISSN 0964-8305, E-ISSN 1879-0208, Vol. 89, 110-114 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study evaluated the decay resistance of ash (Fraxinus excelsior L.), beech (Fagus sylvatica L.), and maple (Acer platanoides L.) wood impregnated by a full cell process with N-methylol melamine (NMM) and combined NMM-metal complex dye (NMM-BS) in aqueous solutions. Basidiomycete decay testing involved incubation with Coniophora puteana (brown rot) and Trametes versicolor (white rot) according to a modified EN 113 (1996) standard, while for the soft rot fungal resistance was evaluated following the standard ENv 807 (2001). NMM and NMM-BS modifications at a WPG range of 7–11% provided decay protection against brown rot resulting in a mass loss less than the required limit (3%). The NMM and NMM-BS modified wood showed increased resistance to white rot decay; however, a higher WPG is needed to prohibit attack from this hardwood specific fungus. The metal-complex dye alone revealed biocidal effects against basidiomycetes. An increased WPG in NMM or NMM-BS had a positive impact against soft rot decay and the lowest mass losses after 32 weeks of exposure were obtained with NMM modification at about 18–21% WPG. NMM modification at this WPG range, however, was not sufficient to protect the wood from soft rot decay. The wood of beech and maple showed slightly higher resistance to all decay types than ash, probably due to the poorer degree of modification of the latter.

  • 5.
    Nilsson, Jonaz
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Johansson, Jimmy
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Sandberg, Dick
    Luleå University, Sweden .
    Densified and thermally modified wood as outer layers in light-weight panels for furniture and joinery.2014Ingår i: Final Cost Action FP0904 Conference : “Recent Advances in the Field of TH and THM Wood Treatment” : May 19-21, 2014, Skellefteå, Sweden : book of abstracts, Luleå tekniska universitet, 2014, 79-80 s.Konferensbidrag (Refereegranskat)
  • 6.
    Voulgaridis, Elias
    et al.
    Aristotle University of Thessaloniki, Greece.
    Passialis, Costas
    Aristotle University of Thessaloniki, Greece.
    Karastergiou, Sotirios
    Technological Educational Institute of Thessaly, Greece.
    Adamopoulos, Stergios
    Technological Educational Institute of Thessaly, Greece.
    Kakaras, Ioannis
    Technological Educational Institute of Thessaly, Greece.
    Foti, Dafni
    Aristotle University of Thessaloniki, Greece.
    Koutsianitis, Dimitrios
    Aristotle University of Thessaloniki, Greece.
    Voulgaridou, Eleni
    Aristotle University of Thessaloniki, Greece.
    Effect of laser drilling on impregnability of fir (Abies borisii regis) and spruce (Picea excelsa) wood2014Ingår i: Wood Structure, Properties and Quality – 2014: 5th RCCWS International Symposium, Moscow State University Press, 2014, 51-56 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    Fir and spruce wood specimens, 2×2 cm in cross section and 34 cm long, were pre-pared with true radial and tangential surfaces. All lateral surfaces of the wood specimens were drilled by laser beams to a depth of 0,4 cm (1/5 of specimen thickness) with two drilling patterns (distance between holes 1×1 cm and 1×2 cm) in order to improve the wood permea-bility of these refractory to impregnation species. After drilling and assessing the drilling ef-fect on mechanical properties of wood, wood specimens, 10 cm long, were impregnated with oil and CCB preservatives by using vacuum (0,6 mmHg) and pressure (1,5 bar) for 15 minutes and 30 minutes, respectively. The effects of the two laser drilling patterns on impreg-nability of fir and spruce wood specimens were measured and assessed. The results showed that both drilling patterns created by laser beams on all lateral surfaces of fir and spruce wood specimens at 0,4 mm depth improved the retention and penetration of preservatives in fir and spruce wood specimens. This effect was more pronounced in fir than in spruce. Between the two drilling patterns, the pattern with distances between holes 1×1 cm was more effective than that with distances 1×2 cm, in both species tested.

  • 7.
    Adamopoulos, Stergios
    et al.
    Technological Educational Institute of Thessaly, Greece.
    Passialis, Costas
    Aristotle University of Thessaloniki, Greece.
    Voulgaridis, Elias
    Aristotle University of Thessaloniki, Greece.
    Moustaizis, Stavros
    Technical University of Crete, Greece.
    Kortsalioudakis, Nathanail
    Technical University of Crete, Greece.
    Petrakis, Panagiotis
    Technical University of Crete, Greece.
    Karastergiou, Sotirios
    Technological Educational Institute of Thessaly, Greece.
    Foti, Dafni
    Technological Educational Institute of Thessaly, Greece.
    Koutsianitis, Dimitrios
    Technological Educational Institute of Thessaly, Greece.
    Voulgaridou, Eleni
    Technological Educational Institute of Thessaly, Greece.
    Effect of laser drilling on mechanical properties of fir (Abies borisii regis) and spruce (Picea excelsa) wood2014Ingår i: Wood Structure, Properties and Quality – 2014: 5th RCCWS International Symposium, Moscow State University Press, 2014, 7-12 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    Fir and spruce wood specimens, 2×2 cm in cross section and 34 cm long, were pre-pared with true radial and tangential surfaces. All lateral surfaces of the wood specimens were drilled by laser beams to a depth of 0,4 cm (1/5 of specimen thickness) with two drilling pat-terns (distance between holes 1 × 1 cm and 1 × 2 cm). After drilling, static bending (MOR, MOE), axial compression strength and toughness were determined and compared with non-drilled control specimens. The effects of the two laser drilling patterns on mechanical proper-ties of fir and spruce wood specimens were measured and assessed. The results showed that the two drilling patterns created by laser beams on all lateral surfaces of fir and spruce wood specimens at 0,4 mm depth did not practically affect the mechanical properties of wood.

  • 8.
    Wimmer, Rupert
    et al.
    Univ Bodenkultur Wien BOKU.
    Johansson, Marie
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för bygg- och energiteknik (BE).
    Effects of Reaction Wood on the Performance of Wood and Wood-Based Products2014Ingår i: The Biology of Reaction Wood / [ed] Gardiner, B., Barnett, J., Saranpää, P., Gril, J., Springer, 2014, 1, 225-248 s.Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    Compression wood in softwoods and tension wood in hardwoods have properties, which adversely affect its usefulness for wood products. This chapter shows that reaction wood can be associated with many unsuitable wood properties. The results vary due to the fact that definitions about occurrence and severity of reaction wood are scarcely documented. A few properties seem to be even benefitting from the presence of reaction wood: the higher smoothness of compression wood surfaces, better shear strength of compression wood, higher toughness and impact resistance when tension wood is present, lower water uptake and swelling in fibreboards containing compression wood, and higher durability against fungi of compression wood. However, these are outweighed by disadvantages, which is the reason why reaction wood has a bad reputation in industry. The problem with reaction wood is that it is in most cases mixed with normal wood, which leads to non-uniform and more variable properties. This may lead to non-uniform swelling and shrinking, causing distortions, with additional problems of reduced strength and unfavourable surface properties. Wood-based materials such as particle boards or fibreboards are generally less prone to problems associated with reaction wood than solid wood products. With knowledge-based production methods the utilization of different wood types, including reaction wood, might be feasible.

  • 9.
    Nilsson, Bengt
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Trublins, Renats
    SLU Alnarp.
    Sallnäs, Ola
    SLU Alnarp.
    Dahlin, Bo
    University of Helsinki, Finland.
    Estimating potential stump harvest from multiple data sources: an example from a county in southern Sweden2014Ingår i: Proceedings of the Precision Forestry Symposium 2014: The anchor of your value chain, Stellenbosch: Stellenbosch University , 2014, 33-34 s.Konferensbidrag (Övrigt vetenskapligt)
  • 10.
    Trischler, Johann
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Sandberg, Dick
    Luleå University of Technology.
    Thörnqvist, Thomas
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Estimating the Annual Above-Ground Biomass Production of Various Species on Sites in Sweden on the Basis of Individual Climate and Productivity Values2014Ingår i: Forests, ISSN 1999-4907, E-ISSN 1999-4907, Vol. 5, nr 10, 2521-2541 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The literature contains a large number of bioclimate, climate and biometric models for estimating the production of different species or stands under specific conditions on a defined site or models giving the distribution of a single species. Depending on the model used, the amount of input data required varies considerably and often involves a large investment in time and money. The purpose of this study was to create a model to estimate the annual above-ground biomass production of various species from site conditions defined by mean annual temperature and mean annual precipitation. For this approach, the Miami model of Lieth was used as a base model with some modifications. This first version of the modified model was restricted to sites in Sweden, where changes in the soil and groundwater level were relatively small, and where the growth of land vegetation was mostly dependent on temperature. A validation of this model has shown that it seems possible to use the Miami model to estimate the annual above-ground biomass production of various species, and that it was possible to compare the annual above-ground biomass production of different species on one site, as well as the annual above-ground biomass production of different species on different sites using the modeled data.

  • 11.
    Trischler, Johann
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Sandberg, Dick
    Luleå Univeristy of Technology.
    Thörnqvist, Thomas
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Evaluating the Competition of Lignocellulose Raw Materials for their Use in Particleboard Production, Thermal Energy Recovery, and Pulp- and Papermaking2014Ingår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 9, nr 4, 6591-6613 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    There is increasing competition for raw materials between particleboard production, thermal energy recovery, and pulp-and papermaking. According to different scenarios, the consumption of lignocellulosic raw materials is increasing, which means that the competition is increasing. The primary production of lignocellulosic raw material in some regions may therefore reach the limit of sustainability; i.e., the lignocellulosic raw material must be used more efficiently to reduce the risk of a shortage. The physical and chemical properties of the lignocellulosic raw material of selected species have therefore been surveyed, and the raw material properties that are important for each of the three competitors have been defined. The aim of the study is to characterise the lignocellulosic raw materials according to the three competing users and to show whether they are high or low in competition. As methods, a relative ranking of the species regarding their raw material properties and regarding the requirements of the competitors as well as cluster analysis were chosen. The results show that the most favourable raw materials are from coniferous species, while monocotyledon species show an opposite trend.

  • 12.
    Hedwall, Per-Ola
    et al.
    Swedish University of Agricultural Sciences.
    Gong, Peichen
    Swedish University of Agricultural Sciences ; European Forest Inst EFINORD.
    Ingerslev, Morten
    University of Copenhagen, Denmark.
    Bergh, Johan
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT). Swedish University of Agricultural Sciences.
    Fertilization in northern forests - biological, economic and environmental constraints and possibilities2014Ingår i: Scandinavian Journal of Forest Research, ISSN 0282-7581, E-ISSN 1651-1891, Vol. 29, nr 4, 301-311 s.Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Forests of northern ecosystems respond slowly to management activities and the possibilities to increase the growth in a short-term perspective and meet swift increases in society's demand for biomass are small. An exception among the silvicultural measures is fertilization which can be applied in combination with present management systems and, almost instantly, enhances forest productivity. There may, however, be both economic and environmental constraints to large-scale applications of fertilizers in forest. Here we review the literature concerning biomass production of forests under different fertilization regimens, environmental constraints and possibilities in northern forests on mineral soils. Further on we discuss the implications of both extensive and more intensive fertilization in relation to the developing bioeconomy, which encompasses the production and conversion of renewable biological resources into food, health and industrial products and energy. Fertilization in Sweden and Finland is currently practiced by extensive fertilization regimens where nitrogen fertilizers are applied once, or up to three times, during a rotation period, mainly in mature forest. This type of fertilization gives, in most cases, a small and transient effect on the environment as well as a high rate of return to the forest owner with low-economic risk. The increase in biomass production, however, is relatively small and consequently the impact on the processing industry and the bioeconomy is limited. More intensive fertilization regimens implying intensive fertilization starting in young forests may, on the other hand, considerably increase the biomass supply and value for the industry. The economic and environmental risks of this type of fertilization may, however, be larger and more research is needed on the effects on the stand level, and especially on the landscape level, including late rotation management of the forest.

  • 13.
    Wagner, Leopold
    et al.
    Vienna University of Technology, Austria.
    Bader, Thomas K.
    Vienna University of Technology, Austria.
    Eberhardsteiner, Josef
    Vienna University of Technology, Austria.
    de Borst, Karin
    University of Glasgow, UK.
    Fungal degradation of softwood cell walls: Enhanced insight through micromechanical modeling2014Ingår i: International Biodeterioration & Biodegradation, ISSN 0964-8305, E-ISSN 1879-0208, Vol. 93, 223-234 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Abstract Fungal degradation is among the greatest hazards for standing trees as well as timber constructions. Herein we aim at gaining more detailed insight into the degradation strategies of wood destroying fungi and the consequences on the mechanical performance of wood. At the macroscale, the occurring losses of mass and of mass density mask effects of altered chemical composition and microstructure. Thus, it is necessary to step down the hierarchical organization of wood to the cell wall scale in order to resolve these changes and their mechanical impact. We present a multiscale micromechanical model which is used to estimate the stiffnesses of the S2 cell wall layer and the compound middle lamella of fungal degraded wood. Data from a detailed chemical, microstructural and micromechanical characterization of white rot and brown rot degraded Scots pine sapwood is analyzed. Comparing predicted cell wall stiffnesses with measured ones confirms the suitability of the approach. The model enables to establish structure–stiffness relationships for fungal degraded wood cell walls and to test hypotheses on yet unknown effects of fungal decay. The latter include the evolution of porosity, modifications of the cell wall polymers resulting in changes of their stiffnesses, as well as increasing cell wall crystallinity. The model predictions in general showed good agreement with the predictions not considering pores in the cell wall. However, this finding does not rule out the formation of porosity. Other degradation related effects like modifications of the cell wall polymers as well as increased crystallinity have the potential to account for stiffness decreases upon the formation of pores.

  • 14.
    Adamopoulos, Stergios
    et al.
    Technological Educational Institute of Thessaly, Greece.
    Passialis, C
    Aristotle University of Thessaloniki, Greece.
    Voulgaridis, E
    Aristotle University of Thessaloniki, Greece.
    Oliver, JV
    Polytechnic University of Valencia, Spain.
    Grammage and structural density as quality indexes of packaging grade papers manufactured from recycled pulps2014Ingår i: Drewno, ISSN 1644-3985, Vol. 57, nr 191, 145-151 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Corrugated packaging production is currently facing the challenge to ensure a satisfactory strength of packaging despite the continuous increase in recycled paper as the main fibrous component. This research addresses a very common technical problem for the corrugated board industry – the difficulty of predicting the properties of paper products produced from heterogeneous sources. Grammage and structural density, being easily available data, were examined as quality parameters of the most common categories of packaging paper in Europe. Grammage, ranging from 100 to 225 g/m2, has been found to be a dominant parameter for estimating the strength properties of paper.

  • 15.
    Adamopoulos, Stergios
    et al.
    Technological Educational Institute of Thessaly, Greece.
    Voulgaridis, Elias
    Aristotle University of Thessaloniki, Greece.
    Passialis, Costas
    Aristotle University of Thessaloniki, Greece.
    Gypsum-based bricks (WoodRub BRICKS) manufactured from recovered wood and rubber2014Ingår i: Performance and maintenance of biobased building materials influencing the life cycle and LCA / [ed] Andreja Kutnar, Miha Humar, Michael Burnard, Mojca Žlahtič, Dennis Jones, 2014, 33-34 s.Konferensbidrag (Övrigt vetenskapligt)
  • 16.
    Karastergiou, Sotirios
    et al.
    Technological Educational Institute of Thessaly, Greece.
    Adamopoulos, Stergios
    Technological Educational Institute of Thessaly, Greece.
    Kakaras, Ioannis
    Technological Educational Institute of Thessaly, Greece.
    Voulgaridis, Elias
    Aristotle University of Thessaloniki, Greece.
    Passialis, Costas
    Aristotle University of Thessaloniki, Greece.
    Foti, Dafni
    Aristotle University of Thessaloniki, Greece.
    Koutsianitis, Dimitrios
    Aristotle University of Thessaloniki, Greece.
    Voulgaridou, Eleni
    Aristotle University of Thessaloniki, Greece.
    Blaskova, Genka
    University of Forestry, Bulgaria.
    Impregnation of fir (Abies borisii regis) and spruce (Picea excelsa) wood with rape oil and CCB preservative2014Ingår i: Wood Structure, Properties and Quality – 2014: 5th RCCWS International Symposium, Moscow State University Press, 2014, 77-82 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    The objective of this study was to examine the retention (kg/m³) and the penetration depth (mm) as well as the impregnated area of cross sections (%) along the hole length, in fir (Abies borisii regis) and spruce (Picea excelsa) wood, after preservative treatment with rape oil and CCB preservative (3,2 %). The wood specimens (5×5 cm or 10×10cm in cross section and 40 cm long) with true radial and tangential surfaces, were treated with the full cell pro-cess. In order to determine the effect of direction (axial, lateral/radial or tangential) on pene-tration of rape oil and CCB preservative, the surfaces of the specimens were coated (laterally in all surfaces and in cross sections, respectively). Retention of rape oil ranged between 21,06 and 78,51 kg/m3 in fir specimens and between 11,20 and 90,32 kg/m3 in spruce specimens, while retention of CCB preservatives fluctuated between 1,68 and 10,05 kg/m3 in fir and be-tween 1,86 and 6,80 kg/m3 in spruce specimens. Penetration depth in all directions as well as impregnated area of cross sections of wood specimens were found to be lower in spruce than in fir for rape oil and, in most cases, for CCB preservative tested. The general conclusion is that both species are difficult to impregnation, but fir is more permeable than spruce.

  • 17.
    Blomqvist, Lars
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Sandberg, Dick
    Luleå tekniska universitet, Luleå University of Technology.
    Johansson, Jimmy
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Influence of veneer orientation on shape stability of plane laminated veneer products2014Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 9, nr 4, 224-232 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    One of the most important quality aspects of a laminated veneer product is its shape stability under changing relative humidity (RH). This study aimed to establish an understanding of how the orientation of individual veneers in the laminate, i.e., orientation according to fibre orientation and orientation of the loose (the side with ‘lathe checks’) or tight side of the veneer, affects the shape stability. Three-ply laminates from peeled veneers of beech (Fagus sylvatica L.) were studied. The four types of laminate were the following: loose sides of all veneers in the same direction (cross and parallel centre ply) and loose sides of the outer veneers facing inward (cross and parallel centre ply). Four replicates of each type yielded 16 samples. The samples were exposed to RH cycling at 20% and 85% RH at 20°C, and the shapes of the samples were determined. The shape stability was influenced by the veneer orientation. Laminations with the middle veneer perpendicular to the top and bottom veneer (cross-laminated) showed the best shape stability, especially when the loose sides of the veneers were oriented the same direction. In parallel-laminated veneers, the laminates with opposite directions of the loose sides in the two outermost veneers showed the best shape stability. The major explanation of the behaviour of the laminates is that the loose side expanded more than the tight side from the dry to the humid climate, which was shown by optical 3D deformation analysis (ARAMISTM). After RH cycling, the laminates with cross plies showed visible surface checks only when the tight side was facing outwards.

  • 18.
    Blom, Åsa
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Thörnqvist, Thomas
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Live storage and drying of storm-felled Norwayspruce (Picea abies, L. Karst.) and Scots pine (Pinussylvestris L.) trees2014Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 9, nr 4, 209-213 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Storm-felled trees left in the forest for a shorter or longer period, affect the quality of the logs. The change in quality ismainly because of attack of fungi and insects, which in turn depends on the moisture content (MC) of the sapwood. Thepurpose of this study was to receive more knowledge about drying of storm-felled trees by investigating how fast winterstorm-felled Norway spruce and Scots pine dried when left in the forest. Sixteen storm-felled spruces with part of the rootsstill in ground contact were selected from three stands and in addition to 10 pines from one of the stands. The trees wereexamined for MC in the sapwood until 21 months after the storm. This study indicates that wind-thrown trees with rootsstill connected to the soil can survive one summer without any value loss caused by draught, fungi and insects. The standconditions can be of importance as the storm-felled trees in the stand, with scattered windthrow, were in best condition afterone year, as they were shadowed by the trees still standing. Comparing spruces and pines with the stand with scatteredwindthrow, pines were more sensitive to drought and reached critical MC earlier.

  • 19.
    Hu, Min
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för byggteknik (BY).
    Local variation in bending stiffness in structural timber of Norway spruce: for the purpose of strength grading2014Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [sv]

    De flesta av de utrustningar för hållfasthetssortering som utnyttjas på deneuropeiska marknaden använder ett medelvärde på elasticitetsmodulen(MOE), beräknat på en relativt stor längd av en sågad planka, som indikativparameter (IP). Sådan hållfasthetssortering ger en noggrannhet i termer avförklaringsgrad på R2 ≈ 0.5, vilket är ganska lågt. Arbetet i denna studiemotiveras av en önskan att öka noggrannheten i hållfasthetssorteringen. Syftetmed denna studie är att bidra med kunskap om lokala variationer iböjstyvhet/MOE med hög upplösning och att lokalisera veka snitt (där kvistarär den viktigaste försvagande faktorn) för konstruktionsvirke.Den aktuella studien introducerar tre metoder som omfattar strukturdynamik,klassisk balkteori och optisk mätning vid bedömningen av lokal styvhet imaterialet. Specifikt:

    •  Metod I, där den lokala böjstyvheten studerades genom de dynamiskaegenskaperna såsom egenfrekvens och modform.
    •  Metod II, där en MOE profil beräknas på basis av information om lokalafibervinklar på ett virkesstyckes ytor. Den lokala fiberorienteringen mätsmed högupplöst laserskanning baserad på den så kallade trakeideffekten.
    •  Metod III, där en MOE-profil fastställdes med hjälp avtöjningsinformation för en hel flatsida av en planka belastad med konstantböjmoment. Det högupplösta töjningsfältet erhölls med hjälp av teknikför Digital Image Correlation (DIC).

    Studien visar att de två sistnämnda metoderna är mycket lämpade för attutvärdera den lokala styvheten i ett virkesstycke. Dessutom visar studien att deMOE-profiler som togs fram med hjälp av de två sistnämnda metoderna,vilka baseras på information om lokala fibervinklar och töjningsfältet på ytan,stämde överens för större delen av virkesstycket. För visa kvistgrupper kan dock den lokala böjstyvheten högre med metoden baserad på fibervinklar.

  • 20.
    Sehlstedt-Persson, Margot
    et al.
    Luleå University of Technology.
    Ahmed, Sheikh Ali
    Luleå University of Technology.
    Metodutveckling för mögeltestning av trä - förstudie: Slutrapport2014Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Syftet med denna förstudie har varit att utveckla enkla och robusta forcerade mögeltester på trä som kan följas och utvärderas kontinuerligt i forskningsprojekt som bedrivs inom beständighetsområdet vid LTU och SP Trätek i Skellefteå. Testerna som gjorts i klimatskåp bygger på naturlig kontaminering och klimatval som gynnar mögeltillväxt.De metoder som utvecklats gör inte anspråk på att kunna erbjuda jämförelser med andra etablerade metoder utan enbart jämförelser inom batcher som ingår i de material- och processvariabler som studeras, exempelvis inom virkestorkning, värmebehandling och impregneringsmetoder.I förstudien utvärderades ett antal olika klimatval i ett klimatskåp som användes i försöken. Mögelpåväxt gynnas av stabil och hög RF, mörker och stillastående luft. Därför täcktes glasdörren till skåpet med svart plast och övre delen av klimatskåpet skärmades av med en mellanplåt eftersom en fläkt cirkulerar luften i kammaren nedre delar. I den övre delen av klimatskåpet gjordes noggranna mätningar av klimatet för att säkerställa ett jämnt och stabilt klimat i olika positioner.Mögelkontaminerat furumaterial sparat från tidigare TCN projekt användes som ”smittokälla” genom att placeras i klimatskåpets nedre del vid valt klimat under 2 dygn för att infektera kammaren med mögelsporer. Därefter placerades försöksmaterialet i klimatskåpets övre del. Smittokällan dvs. det kontaminerade materialet befann sig i skåpet under hela försöket. Inspektion av mögelpåväxtengjordes regelbundet fram tills beslut togs att avbryta försöket och utvärdera mögelpåväxten. Den utvärderingsmetod som används för att bedöma mögelpåväxt bygger på en visuell bedömningsskala översatt i ”praktisk användning” som utarbetats i tidigare TCN-projekt.Den lämpligaste metoden bedöms vara att använda klimatskåpets ”set-points” +27°C/95 % RF samt att avbryta försöket efter ca 12-14 dagar. Mögelgraderna på de undersökta proverna har då varit av samma omfattning som efter ca 100 dagars forcerat utomhustest beskrivit i tidigare TCN-projekt.Den framtagna metoden har använts i fyra ”skarpa” studier som publicerats i vetenskapliga tidskrifter. Detta får ses som att projektet varit lyckat och utgör ett viktigt vetenskapligt bidrag.Metoden beskrivs i detalj i en av dessa publikationer som finns som bilaga till denna rapport nämligen: “Development of a new rapid method for mould testing in a climate chamber: Preliminary tests.” Ahmed, S. A., Sehlstedt-Persson, M. & Morén, T. jul 2013 i :Holz als Roh- und Werkstoff .71 ,4 ,s. 451-461.11 s.Den framtagna metoden har fungerat mycket bra. Metoden har följande fördelar:* Den är enkel, robust och billig.* Mögelpåväxten kan följas på plats.* Det är möjligt att få svar redan efter två veckor på inverkan av olika variabler som undersöks.* Enkel kontaminering – ingen uppodling av speciella mögelarter.* Upp till 44 stycken prover kan ingå i en batch, beroende av dimension.Metoden har följande nackdelar:* Ingen standardiserad metod dvs. det är inte möjligt göra jämförelser mellan olika försöksomgångar utan endast möjligt att göra ”inom-batch” jämförelser.* Ingen kontroll av vilka mögelarter som angriper virket.

  • 21.
    Blomqvist, Lars
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Johansson, Jimmy
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Sandberg, Dick
    Luleå tekniska universitet.
    Modification of surface veneer to reduce damage in laminated veneer products during manufacturing2014Ingår i: Final Cost Action FP0904, Recent Advances in the Field of TH and THM Wood Treatment, May 19-21, Skellefteå, Sweden: Book of abstracts / [ed] Dick Sandberg and Mojgan Vaziri, Luleå: Luleå tekniska universitet, 2014, 50-51 s.Konferensbidrag (Refereegranskat)
  • 22.
    Kielmann, B
    et al.
    Georg-August-University Göttingen, Germany.
    Adamopoulos, Stergios
    Georg-August-University Göttingen, Germany.
    Militz, H
    Georg-August-University Göttingen, Germany ; Technological Educational Institute of Larissa, Greece.
    Koch, G
    Federal Research Institute of Rural Areas, Forestry and Fisheries (vTI), Germany.
    Mai, C
    Georg-August-University Göttingen, Germany.
    Modification of three hardwoods with an N-methylol melamine compound and a metal-complex dye2014Ingår i: Wood Science and Technology, ISSN 0043-7719, E-ISSN 1432-5225, Vol. 48, nr 1, 123-136 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study evaluated the combined modification and staining of ash, beech and maple wood with a low molecular weight N-methylol melamine compound (NMM) and a metal-complex dye. Wood samples were treated with aqueous solutions of 10, 20 and 30 wt% NMM and 5 wt% of the dye. The treatment caused the fixation of the water-soluble dye by the NMM resin. Vacuum pressure impregnation of unsealed wood blocks did not result in different solution uptake and weight percent gain after curing among the three species, but sealing of the surfaces of the wood blocks to allow penetration only into one direction revealed easiest penetrability of beech followed by maple and ash. UV micro-spectrophotometry and light microscopy indicated that NMM was partly deposited in the cell wall and partly in the lumens. Penetration of the metal-complex dye was shown by means of X-ray micro-analysis (SEM–EDX). The study shows that a combined resin modification and staining of the three wood species tested is possible and that NMM causes fixation of the water-soluble dye.

  • 23.
    Blomqvist, Lars
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Johansson, Jimmy
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Sandberg, Dick
    Luleå tekniska universitet, Luleå University of Technology.
    Moisture-induced distortion of laminated veneer products2014Ingår i: Forest Products Society (FPS)  68th International Convention, 2014Konferensbidrag (Refereegranskat)
  • 24.
    Trischler, Johann
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Sandberg, Dick
    Luleå University of Technology.
    Monocotyledons in Particleboard Production: Adhesives, Additives, and Surface Modification of Reed Canary Grass2014Ingår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 9, nr 3, 3919-3938 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    As a supplier to the furniture industry, the particleboard industry is searching for opportunities to reduce costs, weight, and formaldehyde emissions. One such opportunity is to use monocotyledons such as straw and hemp, as well as grasses like reed canary grass. A major problem when using reed canary grass or other monocotyledons in combination with wood is the difference in their surface properties, leading to poor reactivity and wettability with adhesives such as melamine urea formaldehyde. To this end, either the surface of the particles must be modified in some way, or different adhesives must be used. The purpose of this paper is to present adhesives, surfactants, coupling agents, and pre-treatment methods that can be used in combination with monocotyledons to improve compatibility with wood. Some of the methods have been tested on reed canary grass. The results show a wide range of strength values for the joint between wood and untreated or pre-treated reed canary grass glued with different adhesives, with and without a surfactant and a coupling agent. Isocyanate-based adhesives provided relatively strong bonds, and polyvinyl acetate, acryl, and epoxy adhesives were also effective. The most effective method was pre-treatment followed by adhesives in combination with a coupling agent.

  • 25.
    Wagner, Leopold
    et al.
    University of Technology, Austira.
    Bader, Thomas K.
    University of Technology, Austira.
    de Borst, Karin
    University of Glasgow, UK.
    Nanoindentation of wood cell walls: effects of sample preparation and indentation protocol2014Ingår i: Journal of Materials Science, ISSN 0022-2461, E-ISSN 1573-4803, Vol. 49, nr 1, 94-102 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Nanoindentation has become a valuable tool in wood science. It enables to examine the mechanical properties of the wood cell walls, which are polymeric, multi-layered structures with typical thicknesses of a few micrometers. Despite the intensive use of the method for the characterization of wood cell walls, it is not entirely clear yet how the measurement results may be affected by the way the sample is prepared and the indentation is carried out. This manuscript contributes to clarify these issues, by presenting indentation data for a variety of sample preparation techniques and indentation protocols, and by critically evaluating the observed differences of the obtained indentation moduli and hardnesses. Investigations covered the effect of different embedding materials, including testing of non-embedded cell walls, and of repeated exposure to high temperatures during harsh drying before the indentation test. Moreover, potential edge effects were studied when the indentation size approaches the width of the individual cell wall layers. Using different embedding materials as well as testing non-embedded cell walls did not lead to significant changes in the measured properties. Due to damage during the sample preparation, non-embedded cell walls tend to show substantially higher experimental scatter. Repeated drying prior to embedding had no significant effect on the resulting moduli and hardnesses. Finally, it was found that reasonable mechanical properties can be extracted from the cell corner middle lamella (CCML), even when the size of the indent approaches the diameter of the CCML.

  • 26.
    Löf, Magnus
    et al.
    Swedish University of Agricultural Sciences, Southern Swedish Forest Research Center, Sweden.
    Bolte, Andreas
    Johann Heinrich von Thünen-Institut (TI), Federal Research Institute for Rural Areas, Forestry and Fisheries, Institute of Forest Ecosystems, Eberswalde, Germany.
    Jacobs, Douglass F.
    Hardwood Tree Improvement and Regeneration Center, Department of Forestry and Natural Resources, Purdue University, West Lafayette, IN, U.S.A.
    Jensen, Anna M.
    Oak Ridge National Laboratory, Climate Change Science Institute, Oak Ridge, TN, U.S.A.
    Nurse Trees as a Forest Restoration Tool for Mixed Plantations: Effects on Competing Vegetation and Performance in Target Tree Species2014Ingår i: Restoration Ecology, ISSN 1061-2971, E-ISSN 1526-100X, Vol. 22, nr 6, 758-765 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Multi-species mixed plantations can be designed to meet social, economic, and environmental objectives during forest restoration. This paper reports results from an experiment in southern Sweden concerning the influence of three different fast growing nurse tree species on the cover of herbaceous vegetation and on the performance of several target tree species. After 10 years, the nurse trees had reduced the competing herbaceous vegetation but the effect was weak and it may take more than a decade to achieve effective vegetation control. The nurse tree species Betula pendula and Larix x eurolepis did improve stem form in some target tree species, but had a minor effect on survival and growth. The open conditions before crown closure of nurse trees strongly influence seedling performance and so delayed planting of target tree species may provide a means to avoid those conditions. Survival and growth differed greatly among the tree species. Besides the two nurse tree species mentioned above, high survival was found in Picea abies and Quercus robur and intermediate survival in Fagus sylvaticaTilia cordata, and in the N-fixing nurse tree Alnus glutinosa. Survival was low in the target tree species Fraxinus excelsior L. and Prunus avium. For restoration practitioners, our results illustrate the potential of using nurse trees for rapidly building a new forest structure and simultaneously increase productivity, which might be a cost-effective strategy for forest restoration.

  • 27.
    Gustafsson, Åsa
    et al.
    Linnéuniversitetet, Ekonomihögskolan (FEH), Institutionen för ekonomistyrning och logistik (ELO).
    Eliasson, Lars
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Product quality deficiencies in the prefabrication industry for single-family houses2014Ingår i: Wood Material Science & Engineering, ISSN 1748-0272, E-ISSN 1748-0280, Vol. 9, nr 1, 1-11 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the industry for the prefabrication of single-family houses, previous research had indicated that individual companies have problems in securing the product quality of incoming softwood timber. This implies that they need to carry out a quality inspection and adjust the softwood timber when it arrives at their facility in order to fit their production. Opinions within the industry concerning product quality deficiencies differ with regard to the handling procedures and the percentage of perceived deficiencies. However, there are prefabricators of single-family houses that need to find additional areas for use for their purchased softwood timber, and spend several working hours on softwood timber to meet the quality criteria agreed upon. A previous study by Eliasson and Gustafsson puts forward a number of proposals regarding the quality deficiencies of softwood timber in this context. The present work transforms some of these proposals into hypotheses and aims at describing and understanding what affects the perception of product quality deficiencies. Questionnaires were used to collect data. The paper concludes that the purchase volume is indicated to be related to the volume portion of the deficiency in the product quality and that the level of information- and communication-technology support in production (i.e. the degree of automation) is indicated to be related to the inspection activity point. An extension of the proposed hypotheses concludes that the inspection activity point on arrival and/or on delivery into production also affects how companies do perceive product quality deficiencies. Research regarding what affects product quality deficiencies is lacking in recognizing and knowing what is aligned with the perception of product quality deficiencies; the individual companies will have an opportunity to affect and manage their appearance and thereby enhance the use of softwood timber.

  • 28.
    Birbilis, Dimitrios
    et al.
    Technological Educational Institute of Thessaly, Greece.
    Karastergiou, Sotirios
    Technological Educational Institute of Thessaly, Greece.
    Adamopoulos, Stergios
    Technological Educational Institute of Thessaly, Greece.
    Kakavas, Konstantinos
    Technological Educational Institute of Thessaly, Greece.
    Tsioukas, Thomas
    Technological Educational Institute of Thessaly, Greece.
    Properties of black pine (Pinus nigra Arn.) wood treated with hot rape oil2014Ingår i: Wood Structure, Properties and Quality – 2014: 5th RCCWS International Symposium, Moscow State University Press, 2014, 30-34 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    The objective of this study was to examine oil-retention, swelling, adsorption, static bending properties and tensile strength of lap joints of black pine (Pinus nigra Arn.) wood treated with hot rape oil. Wood specimens were impregnated in a steel vessel using the empty cell process (Lowry method). Rape oil retention of black pine specimens ranged between 122 and 193 kg/m3. Total swelling of specimens was not affected by the impregnation but the rate of swelling was decreased. The impregnated specimens had an adsorption of 21%, while the untreated 75%. The oil heat-treatment process was found to affect the tensile strength of lap joints. The impregnated specimens showed a lower tensile strength of about 10% than the un-treated. The treatment did not affect the static bending strength of black pine wood as deter-mined by the modulus of rupture (MOR) values. However, wood elasticity was affected with impregnated specimens showing higher modulus of elasticity (MOE) values than the untreated.

  • 29.
    Birbilis, Dimitrios
    et al.
    Technological Educational Institute of Thessaly, Greece.
    Karastergiou, Sotirios
    Technological Educational Institute of Thessaly, Greece.
    Adamopoulos, Stergios
    Technological Educational Institute of Thessaly, Greece.
    Kakavas, Konstantinos
    Technological Educational Institute of Thessaly, Greece.
    Tsioukas, Thomas
    Technological Educational Institute of Thessaly, Greece.
    Properties of pine (Pinus nigra) and beech (Fagus sylvatica) wood impregnated with hot rape oil and surface treated with turpentine2014Ingår i: New Materials and Technologies in the Function of Wooden Products: Proceedings / [ed] Ivica Grbac, Faculty of Forestry , 2014, 1-6 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    The objective of this study was to examine oil-retention, adsorption, swelling and tensile strength of lap joints of wood treated with hot rape oil. Wood specimens of two species (Fagus sylvatika and Pinus nigra) were impregnated in a steel vessel using the empty cell process (Lowry method). Several impregnated specimens were additionally surface treated with turpentine. Rape oil retention ranged between 124 and 189 kg/m3 for pine wood specimens and between 187 and 285 kg/m3 for beech wood specimens. For both species, the impregnated specimens had an adsorption of about 20%, while the untreated near 60%. Total swelling of specimens was not affected by the impregnation but the rate of swelling was decreased. The impregnated specimens had a little lower tensile strength mostly when glued with polyurethane (PU). Surface treatment with turpentine slightly improved tensile strength of lap joints.

  • 30.
    Adamopoulos, Stergios
    TEI Thessaly, Greece.
    Recovery and utilization of wood and rubber at the end of their lifespan to produce innovative products2014Ingår i: Development and Business Prospects in Thessaly by Symbiotic Utilization of Agricultural and Industrial Solid Waste to Produce Materials and Energy, November 24, Larissa, Greece, 2014Konferensbidrag (Övrigt vetenskapligt)
  • 31.
    de Borst, Karin
    et al.
    University of Glasgow, UK.
    Bader, Thomas K.
    Vienna University of Technology, Austria.
    Structure-€“function relationships in hardwood: Insight from micromechanical modelling2014Ingår i: Journal of Theoretical Biology, ISSN 0022-5193, E-ISSN 1095-8541, Vol. 345, 78-91 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Abstract A micromechanical model is presented that predicts the stiffness of wood tissues in their three principal anatomical directions, across various hardwood species. The wood polymers cellulose, hemicellulose, and lignin, common to all wood tissues, serve as the starting point. In seven homogenisation steps, the stiffnesses of these polymers are linked to the macroscopic stiffness. The good agreement of model predictions and corresponding experimental data for ten different European and tropical species confirms the functionality and accuracy of the model. The model enables investigating the influence of individual microstructural features on the overall stiffness. This is exploited to elucidate the mechanical effects of vessels and ray cells. Vessels are shown to reduce the stiffness of wood at constant overall density. This supports that a trade-off exists between the hydraulic efficiency and the mechanical support in relation to the anatomical design of wood. Ray cells are shown to act as reinforcing elements in the radial direction.

  • 32.
    Blomqvist, Lars
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Sterley, Magdalena
    SP Wood Technology.
    Sandberg, Dick
    Luleå tekniska universitet, Luleå University of Technology.
    Johansson, Jimmy
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    The influence of veneer modification on adhesive bond strength2014Ingår i: Proceedings of the 10th meeting of the Northern European network for wood science and engineering (WSE) / [ed] Peter Wilson, Edinburg, Scotland, 2014, 150-155 s.Konferensbidrag (Refereegranskat)
  • 33.
    Högberg, Karl-Anders
    et al.
    Skogforsk.
    Hallingbäck, Henrik
    SLU.
    Säll, Harald
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Johansson, Marie
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för bygg- och energiteknik (BE).
    Jansson, Gunnar
    Skogforsk.
    The potential for the genetic improvement of sawn timber traits in Picea abies2014Ingår i: Canadian Journal of Forest Research, ISSN 0045-5067, E-ISSN 1208-6037, Vol. 44, nr 4, 273-280 s.Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study evaluated the potential for the selective genetic improvement of the structural quality traits important in sawn Norway spruce (Picea abies (L.) Karst.) timber based on early and nondestructively assessed field traits. From a 34-year-old Norway spruce trial situated in southern Sweden, 401 butt logs were sampled and sawn to produce two 50 × 100 mm boards that were dried to an 18% moisture content. Structural quality traits were assessed, and genetic parameters were estimated, including additive genetic variance, heritability, and their genetic correlations with field traits. Board twisting, density, and modulus of elasticity (MOE, stiffness) were found to have appreciable heritabilities (0.23–0.44). Board twist was found to have a strong genetic correlation with grain angle measured under bark in the field (0.93), and both board MOE and density exhibited strong genetic correlations with field-assessed pilodyn penetration (–0.75 and –0.91, respectively). Although these observations were made on a thinning material comprising mainly juvenile wood, they nonetheless suggest grain angle and pilodyn penetration to be promising candidates as selection criteria for Norway spruce breeding. Heritabilities of other sawn timber traits were lower and the genetic correlations between these traits and field traits were also lower, variable, and had large estimation errors.

  • 34.
    Sandberg, Dick
    et al.
    Luleå Univ Technol.
    Vasiri, Mojgan
    Luleå Univ Technol.
    Trischler, Johann
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Ohman, Micael
    Luleå Univ Technol.
    The role of the wood mechanical industry in the Swedish forest industry cluster2014Ingår i: Scandinavian Journal of Forest Research, ISSN 0282-7581, E-ISSN 1651-1891, Vol. 29, nr 4, 352-359 s.Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    The forest and forest products form one of the most important basis for the transfer to a bio-based economy in Sweden. About 75% of the area covered by forest in Sweden is used industrially to produce raw material for the wood-refining industries. Every year, this cluster uses 75 million m(3) of roundwood and has an export value of (sic)12 billion. This review paper is devoted to the wood mechanical industry, i.e. the industry which turns the forest into sawn timber, packaging, construction wood, furniture and interior fittings. The sawmills consume about half of the volume of softwood which is felled, and about two-thirds of the sawn timber go to export without any further refining within the country. Nevertheless, in spite of the relatively low degree of refinement in the sawmill and the fact that the sawmills in general over time have a very low profitability, they are responsible for 70-80% of the forest owners' profits on the sale of timber. An increased upgrading of the sawn timber within the country is desirable from a national economic viewpoint increased employment opportunities, increased export income, etc. It should then in the first place be for products with a higher added value, such as furniture and fittings. Today, the refinement value is 15-20 times higher for products from joinery and furniture industries compared to that of the sawn timber, and the added value of the wood within the building industry is only about 1.5 times.

  • 35.
    Mahnert, Karl-Christian
    et al.
    Norwegian Institute of Wood Technology, Norway ; Georg August University of Göttingen, Germany.
    Adamopoulos, Stergios
    Technological Educational Institute of Thessaly, Greece.
    Koch, Gerald
    Thünen Institute of Wood Research, Germany.
    Militz, Holger
    Georg August University of Göttingen, Germany.
    UV-microspectrophotometry: A method to prove wood-modification with MMF?2014Ingår i: European Conference on Wood Modification 2014, 2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    The modification of wood with methylolated melamine formaldehyde resin (MMF) belongs to the group of impregnation modifications. In the course of this study, Koto sapwood samples were impregnated with MMF-solutions in a full-cell vacuum-pressure process. The samples were cured at a maximum temperature of 120 ºC for 24 hours. To characterize the modification, the solution uptake (SU) and weight percent gain (WPG) of the samples were calculated. The fixation of the melamine as parameter for the degree of curing was examined by C/N analysis. Areal UV-microspectrophotometry (UMSP)-scans of ultra-thin transverse sections of an untreated control and MMFmodified samples at 240 nm were recorded. Additionally, photometric point measurements with a spot size of 1 μm2 in the range 230 nm and 350 nm were conducted. UMSP was proven as suitable technique for the quantitative analysis of MMF-modified wood.

  • 36.
    Blomqvist, Lars
    et al.
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Johansson, Jimmy
    Linnéuniversitetet, Fakulteten för teknik (FTK), Institutionen för skog och träteknik (SOT).
    Sandberg, Dick
    Luleå tekniska universitet, Luleå University of Technology.
    Veneer modification for improved formability when moulding laminated veneer products2014Ingår i: Forest Products Society (FPS)  68th International Convention, 2014Konferensbidrag (Refereegranskat)
  • 37.
    Sidorova, Ekaterina
    et al.
    Luleå University of Technology.
    Ahmed, Sheikh Ali
    Luleå University of Technology.
    Diego, Elustondo
    Luleå University of Technology.
    Wood thermal-modification at Luleå University of Technology2014Ingår i: Final Cost Action FP0904 Conference “Recent Advances in the Field of TH and THM Wood Treatment” May 19-21, 2014, Skellefteå, Sweden: Books of Abstracts / [ed] Mojgan Vaziri, Dick Sandberg, Skellefteå: Luleå tekniska universitet , 2014, 75-75 s.Konferensbidrag (Refereegranskat)
    Abstract [en]

    The Wood Physics group at Luleå University of Technology (LTU) has the vision of transforming Swedish solid wood into the material of choice for the renewable economy of the future. To realize that vision, the group believes, stability and durability of local softwood species must be enhanced at a reasonable cost without jeopardizing the natural beauty of this environmentally friendly material. One of the methods for enhancing stability and durability of solid wood is thermal modification, and LTU's Wood Physics group has vast experience in developing and evaluating thermal modification process. In simple words, thermal modification involves exposing the wood to relatively high temperatures, between 160o C and 240o C depending on the products and technologies used, and in the absence of oxygen to avoid degradation of the wood by combustion. It has been proved that these relatively high temperatures modify the chemical structure of the wood polymers (cellulose, hemicellulose and lignin), and wood becomes less prone to absorb moisture from the environment and more resistance to biological degradation. There are a number of thermal modification methods that have been implemented in Europe at the commercial level, such as ThermoWood® and WTT thermo-treatment. ThermoWood® process is performed under normal atmospheric pressure with superheated steam containing as little oxygen as possible. The wood is first dried to almost 0% moisture content with steam temperatures up to 130°C, and then exposed to steam temperatures between 185°C to 212°C for a few hours. Afterward the vapor temperature is reduced to below 90°C to saturate the steam and allow the wood regain moisture. The WTT thermotreatment is performed with saturated steam under pressure up to 20 bars and temperatures between 160°C and 210°C, so the wood is not dried during the process. In the last years, LTU's Wood Physics group has performed several studies in collaboration with local wood producers interested in the evaluation and optimization of thermal modification processes. To study thermal modification in laboratory, LTU's Wood Physics has built pilot scale kiln/thermal-modification unit that fits through the field of view of a CT-scanner unit specially adapted for wood material studies. This combined equipment allowed measuring wood density profiles through entire thermal modification process, thus providing valuable information about the effect of the process conditions in the material. More recently, LTU's Wood Physics group became interested in the process of thermal modification by boiling in linseed oil for 2 to 4 hours. This technology is available in the market, but the novelty at LTU was the implementation of an additional oil impregnation cooling phase in which the wood is submerged in cool oil after thermal modification. This creates a sudden contraction of the gases inside the wood, which in turn draws considerable amounts of oil into the wood. The authors believe that this combined thermal-modification/oil-impregnation treatment offers a simple but effective methodology for simultaneously: 1) enhance the stability and durability of solid wood, 2) impregnate the wood surfaces with oil for increasing the repellency to moisture. This presentation includes an example of the combined thermal-modification/oil-impregnation treatment applied to common Swedish softwood and hardwood species. Both species were treated by using the WTT heat treatment technology and impregnated with different types of preservative oils. After impregnation, the samples were tested for water repellency, dimensional stability, and resistance to mould. Water repellency and dimensional stability were assessed for both liquid water and air relative humidity, and the resistance to oil leaching was determined by exposing the treated wood to cycles in which the samples absorbed water by immersion and then release the water under vacuum. As expected, the treatments showed a significant improvement in the water repellency and dimensional stability of the wood. Overall, untreated wood was more stable after thermal modification, and thermally modified wood was more stable after oil impregnation. The resistance to mould was evaluated by using an accelerated technique also developed by the Wood Physics group at Luleå University of Technology. The technique consists in placing the wood samples in the upper zone of a conditioning chamber in which there are other pieces of wood already infected by mould in the lower zone. Typically, the source of mould is pine sapwood infected with mould of aspergillus, rhizopus, penicillium genus along with other various species, and the test samples are exposed approximately 20 days to the infected environment. After incubation, the incidence of mould over the surfaces is graded in scale from 0 to 6 based on the visual assessment of two independent observers. The results of the study showed that some of the oil impregnation treatments did not significantly improved mould resistance, and it was still questionable whether the oil would not leach from the wood when the products are in service. Future research in wood modification would be certainly needed to find the right thermal-modification/oil-impregnation combination for the right application, as well as to realize the vision of transforming solid wood in the material of choice for the renewable economy of future.

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