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  • 1.
    Ah Shenga, Pedro António
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Bomark, Peter
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Broman, Olof
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Sandberg, Dick
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Simulation of Tropical Hardwood Processing: Sawing Methods, Log Positioning, and Outer Shape2015In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 10, no 4, p. 7640-7652Article in journal (Refereed)
    Abstract [en]

    To increase understanding of breakdown strategies for Mozambican timber, simulations were carried out using different sawing patterns that can be alternatives to the low degree of refinement performed for export today. For the simulations, 3D models of 10 Jambirre and 5 Umbila logs were used. The log shape was described as a point cloud and was acquired by 3D-laser scanning of real logs. Three sawing patterns (cant-sawing, through-and-through sawing, and square-sawing) were studied in combination with the log positioning variables skew and rotation. The results showed that both positioning and choice of sawing pattern had a great influence on the volume yield. The results also showed that the log grade had an impact on the sawing pattern that should be used for a high volume yield. The volume yield could be increased by 3 percentage points by choosing alternative sawing patterns for fairly straight logs and by 6 percentage points for crooked logs, compared to the worst choice of sawing pattern.

  • 2.
    Ah Shenga, Pedro
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Bomark, Peter
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Broman, Olof
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Hagman, Olle
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    3D Phase-shift Laser Scanning of Log Shape2014In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 9, no 4, p. 7593-7605Article in journal (Refereed)
    Abstract [en]

    In this paper, a portable scanner to determine the 3D shape of logs was evaluated and compared with the measurement result of a computer tomography scanner. Focus was on the accuracy of the shape geometry representation. The objective is to find a feasible method to use for future data collection in Mozambique in order to build up a database of logs of tropical species for sawing simulations. The method chosen here was a 3D phase-shift laser scanner. Two logs, a birch log with bark and a Scots pine log without bark, were scanned, resulting in 450 cross sectional “images” of the pine log and 300 of the birch log. The areas of each point cloud cross section were calculated and compared to that of the corresponding computer tomography cross section. The average area difference between the two methods was 2.23% and 3.73%, with standard deviations of 1.54 and 0.91, for the Scots pine and birch logs, respectively. The differences in results between the two logs are discussed and had mainly to do with presence of bark and mantle surface evenness. Results show that the shape measurements derived from these methods were well correlated, which indicates the applicability of a 3D phase-shift laser scanning technology for gathering log data.

  • 3.
    Ah Shenga, Pedro
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Bomark, Peter
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Broman, Olof
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Sandberg, Dick
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    The Effect of Log Position Accuracy on the Volume Yield in Sawmilling of Tropical Hardwood2016In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 11, no 4, p. 9560-9571Article in journal (Refereed)
    Abstract [en]

    This study investigated the effect of the positioning of the log before sawing on the volume yield of sawn timber from tropical hardwood species. Three positioning parameters were studied, the offset, skew, and rotation, combined with two sawing patterns of cant-sawing and through-and-through sawing. A database consisting of two tropical hardwood species with very different outer shapes, jambirre (Millettia stuhllmannii Taub.) and umbila (Pterocarpus angolensis DC.), was used to simulate the sawing process. The result of the simulation revealed that, according to the combined effect of offset, skew, and rotation positioning, the positioning of the log before sawing is extremely important to achieve a high volume yield of sawn timber. The positioning parameter that has the highest effect on the volume yield is the rotation, and the variation in the volume yield associated with a deviation in the positioning can reduce the volume yield of sawn timber by between 7.7% and 12.5%.

  • 4.
    Axelsson, Ann
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    How Planer Settings Affect Timber Properties2014In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 9, no 4, p. 6432-6439Article in journal (Refereed)
  • 5.
    Berg, Sven
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Turesson, Jonas
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Ekevad, Mats
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Björnfot, Anders
    Faculty of Engineering, Department of Manufacturing and Civil Engineering, Norwegian University of Science and Technology, Gjøvik, Norway.
    In-plane Shear Modulus of Cross-laminated Timber by Diagonal Compression Test2019In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 14, no 3, p. 5559-5572Article in journal (Refereed)
    Abstract [en]

    Cross-laminated timber (CLT) is an engineered wood material that is used in the construction industry, e.g., for floors, walls, and beams. In cases where CLT-elements are used as shear walls, the in-plane-stiffness is an important property. For non-edge glued CLT, in-plane shear stiffness is lower than for edge-glued CLT. To evaluate the non-edge glued CLT panel’s in-plane shear modulus, the diagonal compression test and finite element (FE) simulation was used. FE-models with both isotropic and orthotropic material models were used to calculate the shear stiffness. The FE models using pure shear loads were used as a reference to determine the correct value of the shear modulus. To verify the FE simulations, diagonal compression tests were conducted on 30 CLT samples. A calibration formula was derived using the least square method for calculation of shear modulus. The formula gave accurate results. The results showed that FE simulations can reproduce the same shear stiffness as tests of non-edge glued 3-layer and 5-layer CLT panels.

  • 6.
    Björngrim, Niclas
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Fjellström, Per-Anders
    Science Partner.
    Hagman, Olle
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Factory Mounted and Retrofit Passive Resistance Sensors Adapted to Monitor Moisture Content in Timber Bridges2017In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 12, no 4, p. 7218-7227Article in journal (Refereed)
    Abstract [en]

    The biggest threats to the longevity of a timber bridge are rot and decay. Wood protection by design, inspections, and monitoring of the bridge for elevated moisture content will ensure that the full service life of the structure can be achieved. Today's sensors for moisture content measurements are limited in their functionality and range. This paper presents a sensor that can be both factory installed and retrofitted, which can measure the moisture content through the cross-section of the member in a timber bridge. The sensor has been mounted on Sundbron bridge during manufacturing and retrofitted on Gislaved bridge. The ensuing measurements helped to adjust a design flaw on Gislaved bridge. Monitoring of Sundbron showed that the bridge deck dried up after the bridge had been exposed to sleet and snow during the on-site assembly of the stress laminated bridge deck

  • 7.
    Björngrim, Niclas
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Fjellström, Per-Anders
    SP - Science Partner.
    Hagman, Olle
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Resistance measurements to find high moisture content inclusions adapted for large timber bridge cross-sections2017In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 12, no 2, p. 3570-3582Article in journal (Refereed)
    Abstract [en]

    One challenge of monitoring and inspecting timber bridges is the difficulty of measuring the moisture content anywhere other than close to the surface. Damage or design mistakes leading to water penetration might not be detected in time, leading to costly repairs. By placing electrodes between the glulam beams, the moisture content through the bridge deck can be measured. Due to the logarithmic decrease of the resistance in wood as a function of electrode length, the model must be calibrated for measurement depth. Two models were created: one for electrode lengths of 50 mm and one for electrode lengths up to 1355 mm. The model for short electrodes differed by no more than 1 percentage points compared with the oven dry specimens. The model for long electrodes differed up to 2 percentage points for lengths up to 905 mm, and over that it could differ up to 4 percentage points.

  • 8.
    Björngrim, Niclas
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Hagman, Olle
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Wang, Alice
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Multivariate Screening of the Weather Effect on Timber Bridge Movements2016In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 11, no 4, p. 8890-8899Article in journal (Refereed)
    Abstract [en]

    Monitoring displacements and weather impact of complex structures such as a large cable stayed footbridge generates large amount of data. In order to extract, visualize and classify health-monitoring data to get a better comprehension multivariate statistical analysis is a powerful tool. This paper is a screening to evaluate if principal component analysis is useful on health monitoring data. Principal component analysis (PCA) and projections to latent structures by means of partial least squares (PLS) modeling were used to achieve a better understanding of the complex interaction between bridge dynamics and weather effects. The results show that principal component analysis (PCA) give good overview of the collected data, and PLS modeling show that winds from east and west best explain bridge movements.

  • 9.
    Björngrim, Niclas
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Hagman, Olle
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Wang, Xiaodong (Alice)
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Moisture Content Monitoring of a Timber footbridge2016In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 11, no 2, p. 3904-3913Article in journal (Refereed)
  • 10.
    Blomqvist, Lars
    et al.
    Linnӕus University, Department of Building Technology, Växjö, Sweden. RISE, Research Institute of Sweden.
    Berg, Sven
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Sandberg, Dick
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering. Department of Wood Processing and Biomaterials, Czech University of Life Sciences Prague, Prague, Czech Republic.
    Distortion in laminated veneer products exposed to relative-humidity variations: Experimental studies and finite-element modelling2019In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 14, no 2, p. 3768-3779Article in journal (Refereed)
    Abstract [en]

    A shortcoming of the laminated bending process is that the product may become distorted after moulding. This study focused on the influence of fibre orientation deviation for individual veneers on the distortion of a moulded shell. The distortion of 90 cross-laminated shells of the same geometrical shape, consisting of seven peeled birch veneers, were studied under relative humidity variation. All the veneers were straight-grained in the longitudinal-tangential plane, but to simulate a deviation in fibre orientation, some of the individual veneers were oriented at an angle of 7° relative to the main orientation of the other veneers in the laminate. A finite element model (FEM) was applied to study the possibility of predicting the results of a practical experiment. The study confirms the well-known fact that deviation in fibre orientation influences shape stability. The results also show how the placement of the abnormal veneer influences the degree of distortion. From this basic knowledge, some improvements in the industrial production were suggested. However, the FE model significantly underestimated the results, according to the empirical experiment, and it did not show full coherence. The survey shows the complexity of modelling the behaviour of laminated veneer products under changing climate conditions and that there is a great need to improve the material and process data to achieve accurate simulations. Examples of such parameters that may lead to distortion are density, annual ring orientation in the cross section of the veneer, the orientation of the loose and tight sides of the veneer, and parameters related to the design of the moulding tool.

  • 11.
    Brännström, Mattias
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    The impact of a strength grading process on sawmill profitability and product quality2009In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 4, no 4, p. 1430-1454Article in journal (Refereed)
    Abstract [en]

    A strength grading process, starting with log grading, was studied with respect to grading yield, impact on quality, and economic efficiency when visual grades according to Nordic grading rules were used for alternate product comparison. Pine (Pinus sylvestris) and spruce (Picea abies) logs and boards were graded with several varieties of commercial grading and strength-grading equipment. The boards were destructively tested, and the European grade-determining properties strength, stiffness, and density were measured. Models for these were made by partial least squares and validated. A method for the derivation of settings for multiple indicating properties, which increased yield in some cases, was proposed and evaluated. Grading to grade combinations of C40, C30, and C18 was done. The impact of visual override based on deformations was also studied. A simplified economic and sensitivity analysis was done. The outcome was that log grading can be used for strength grading with good economic and quality results. Strength pregrading on logs improves sawmill economy, depending on the species and market situation. Drying quality greatly influences the yield through visual override grading on deformations. Market prices of high grades (>C30) must improve in order to stimulate supply, as it is more economical to produce lower grades.

  • 12. Brännström, Mattias
    et al.
    Manninen, Janne
    Stora Enso AB, Porvoo.
    Oja, Johan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Predicting the strength of sawn wood by tracheid laser scattering2008In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 3, no 2, p. 437-451Article in journal (Refereed)
    Abstract [en]

    An industrial laser light scattering scanner, designed to detect the spiral grain angle of logs by the light scattering along the grain, was used on two large samples of Norway spruce (Picea abies (var. Karst)) in various sawn dimensions (approximately 750 pieces). Additional measurements were made by other techniques, such as X-ray scanning, resonance frequency measurement, and various manual measurements. The strength properties of the boards were measured by destructive testing in four-point bending according to European standard. Multivariate methods (PLS) were used to model the relationship between the bending strength of the board (MOR) and the measurements. Based only on the output from the simple tracheid scattering equipment, a model for MOR achieved an R² exceeding 0.3. Combinations with average density or outer shape parameters from log scanning resulted in R² 0.4 and 0.3 respectively, although these parameters alone only accounted for R² 0.2. The results can be used to increase the understanding of strength in wood and in an improved industrial strength-grading process.

  • 13.
    Buck, Dietrich
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Hagman, Olle
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Production and In-Plane Compression Mechanics of Alternatively Angled Layered Cross-Laminated Timber2018In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 13, no 2, p. 4029-4045Article in journal (Refereed)
    Abstract [en]

    Increasing awareness of sustainable building materials has led to interest in enhancing the structural performance of engineered wood products. This paper reports mechanical properties of cross-laminated timber (CLT) panels constructed with layers angled in an alternative configuration on a modified industrial CLT production line. Timber lamellae were adhesively bonded together in a single-step press procedure to form CLT panels. Transverse layers were laid at an angle of 45°, instead of the conventional 90° angle with respect to the longitudinal layers’ 0° angle. Tests were carried out on 20 five-layered CLT panels divided into two matched groups with either a 45° or a 90° configuration; an in-plane uniaxial compressive loading was applied in the principal orientation of the panels. These tests showed that the 45°-configured panels had a 30% higher compression stiffness and a 15% higher compression strength than the 90° configuration. The results also revealed that the 45°-configured CLT can be industrially produced without using more material than is required for conventional CLT 90° panels. In addition, the design possibility that the 45°-configured CLT can carry a given load while using less material also suggests that it is possible to use CLT in a wider range of structural applications.

  • 14.
    Buck, Dietrich
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Wang, Alice
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Hagman, Olle
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Gustafsson, Anders
    SP Technical Research Institute of Sweden, SP Sustainable Built Environment, Skellefteå, Sweden, SP Trätek, SP Technical Research Institute of Sweden, Skellefteå.
    Bending Properties of Cross Laminated Timber (CLT) with a 45° Alternating Layer Configuration2016In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 11, no 2, p. 4633-4644Article in journal (Refereed)
    Abstract [en]

    Bending tests were conducted with cross laminated timber (CLT) panels made using an alternating layer arrangement. Boards of Norway spruce were used to manufacture five-layer panels on an industrial CLT production line. In total, 20 samples were tested, consisting of two CLT configurations with 10 samples of each type: transverse layers at 45° and the conventional 90° arrangement. Sample dimensions were 95 mm × 590 mm × 2000 mm. The CLT panels were tested by four point bending in the main load-carrying direction in a flatwise panel layup. The results indicated that bending strength increased by 35% for elements assembled with 45° layers in comparison with 90° layers. Improved mechanical load bearing panel properties could lead to a larger span length with less material.

  • 15.
    Buck, Dietrich
    et al.
    Department of Engineering Sciences and Mathematics, Luleå University of Technology.
    Wang, Xiaodong (Alice)
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Hagman, Olle
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Gustafsson, Anders
    SP Technical Research Institute of Sweden, SP Sustainable Built Environment, Skellefteå, Sweden.
    Comparison of Different Assembling Techniques Regarding Cost, Durability, and Ecology: A Survey of Multi-layer Wooden Panel Assembly Load-Bearing Construction Elements2015In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 10, no 4, p. 8378-8396Article in journal (Refereed)
    Abstract [en]

    Wood is a pure, sustainable, renewable material. The increasing use of wood for construction can improve its sustainability. There are various techniques to assemble multi-layer wooden panels into prefabricated, load-bearing construction elements. However, comparative market and economy studies are still scarce. In this study, the following assembling techniques were compared: laminating, nailing, stapling, screwing, stress laminating, doweling, dovetailing, and wood welding. The production costs, durability, and ecological considerations were presented. This study was based on reviews of published works and information gathered from 27 leading wood product manufacturing companies in six European countries. The study shows that the various techniques of assembling multi-layer wooden construction panel elements are very different. Cross laminated timber (CLT) exhibited the best results in terms of cost and durability. With regard to ecological concerns, dovetailing is the best. Taking into account both durability and ecological considerations, wooden screw-doweling is the best. These alternatives give manufacturers some freedom of choice regarding the visibility of surfaces and the efficient use of lower-quality timber. CLT is the most cost-effective, is not patented, and is a well-established option on the market today.

  • 16.
    Cai, Lili
    et al.
    Department of Material Science and Engineering, Fujian Agriculture and Forestry University, Fuzhou.
    Chen, Tingjie
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering. tingjie.chen@ltu.se .
    Wang, Wei
    Department of Material Science and Engineering, Fujian Agriculture and Forestry University, Fuzhou.
    Huang, Daobang
    Department of Material Science and Engineering, Fujian Agriculture and Forestry University, Fuzhou.
    Wei, Qihua
    Department of Material Science and Engineering, Fujian Agriculture and Forestry University, Fuzhou.
    Lin, Ming
    Department of Material Science and Engineering, Fujian Agriculture and Forestry University, Fuzhou.
    Xie, Yongqun
    Department of Material Science and Engineering, Fujian Agriculture and Forestry University, Fuzhou.
    Optimization of aluminum/silicon compounds on fire resistance of old corrugated container fiber foam material2016In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 11, no 3, p. 6505-6517Article in journal (Refereed)
    Abstract [en]

    Old corrugated container fiber foam material (OCCM) was prepared using a liquid frothing approach. The effect of the content of Al/Si compounds, the molar ratio of Al3+/SiO2, and different addition form on the limited oxygen index (LOI) and residue percentage of OCCM was optimized using an orthogonal design. The fire resistance of OCCM was best when the content of Al/Si compounds was 900 mL, the molar ratio of Al3+/SiO2 was 1:1, and the aluminum sulfate solution was added first, followed by the separately added sodium silicate solution. Under these conditions, the LOI and residue percentage of OCCM reached 32.3 and 53.51%, respectively. Thermogravimetric analysis indicated that Al/Si compounds promoted char formation and reduced the heat release of the optimized OCCMs during depolymerisation. Compared with the control group, the residue percentage of optimized OCCM was increased from 12.49% to 37.98%. Fourier transform infrared spectroscopy identified the functional groups of Al/Si compounds in the optimized OCCMs, confirming that pyrolysis of the optimized OCCMs was affected by Al/Si compounds.

  • 17.
    Cai, Lili
    et al.
    Fujian Agriculture and Forestry University, Fuzhou, China.
    Zhuang, Biaorong
    Fujian Agriculture and Forestry University, Fuzhou, China.
    Hang, Daobang
    Fujian Agriculture and Forestry University, Fuzhou, China.
    Wang, Wei
    Fujian Agriculture and Forestry University, Fuzhou, China.
    Niu, Min
    Fujian Agriculture and Forestry University, Fuzhou, China.
    Xie, Yongqun
    Fujian Agriculture and Forestry University, Fuzhou, China.
    Chen, Tingjie
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Wang, Alice
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Ultra-Low Density Fibreboard with Improved Fire Retardance and Thermal Stability using a Novel Fire- Resistant Adhesive2016In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 11, no 2, p. 5215-5229Article in journal (Refereed)
    Abstract [en]

    A novel fire-resistant adhesive made from polyvinyl alcohol, urea, phosphoric acid, and starch was demonstrated for use as a binder and fire retardant to produce ultra-low density fibreboard (ULDF) with clear environmental benefits. The results from Fourier transform infrared spectroscopy showed the presence of chemical bonding between fire- resistant adhesives and ULDFs. The limiting oxygen index (LOI), combustion behaviour, and thermal stability were characterized using a LOI text, cone calorimeter, and thermal analyzer, respectively. The results demonstrated that the LOI value of the fire-retardant ULDF can reach up to 34.2 with 300 mL of fire-resistant adhesive. It was established that the additive noticeably reduced the peak of heat release rate, total heat release, and total smoke release of ULDF. Their morphologies after combustion were elucidated using a scanning electron microscope, and a char layer in the condensed phase was observed. Thermal analysis showed that the thermal stability of ULDF improved dramatically and the residual weight increased 4-fold, to 48.32%. Therefore, such ULDFs will be tremendously attractive as renewable, sustainable, and bio-based insulating materials.

  • 18.
    Chen, Tingjie
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering. Fujian Agriculture and Forestry University, Fuzhou, China.
    Liu, Jinghong
    Fujian Agriculture and Forestry University, Fuzhou, China.
    Wu, Zhenzeng
    Fujian Agriculture and Forestry University, Fuzhou, China.
    Wang, Wei
    Fujian Agriculture and Forestry University, Fuzhou, China.
    Niu, Min
    Fujian Agriculture and Forestry University, Fuzhou, China.
    Wang, Alice
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Xie, Yongqun
    Fujian Agriculture and Forestry University, Fuzhou, China.
    Evaluating the Effectiveness of Complex Fire-Retardants on the Fire Properties of Ultra-low Density Fiberboard (ULDF)2016In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 11, no 1, p. 1796-1807Article in journal (Refereed)
    Abstract [en]

    The preparation conditions of complex fire-retardant (FR) agents containing boron compounds (BF, X1), nitrogen-phosphorus compounds (NPF, X2), silicon compounds (SF, X3), and halogen compounds (HF, X4) for ultra-low density fiberboard (ULDF) were optimized using a response surface methodology. The effects and interactions of X1, X2, X3, and X4 on the fire properties of ULDF were investigated. An optimum char yield of 61.4% was obtained when the complex fire-retardant agents contained 33.9% boron, 27.2% nitrogen-phosphorus, 15.0% silicon, and 28.6% halogen. Compared with control fiberboard (CF), the heat release rate (HRR) profiles of all fiberboards with FRs were reduced. The peak HRR reduction in BF and NPF was more pronounced than for SF and HF at this stage. And the mixed fiberboard (MF) had the lowest pkHRR of 75.02 kW m−2. In total heat release (THR) profiles, all fiberboards with FRs were lower than the CF. Unlike the HRR profiles, HF had the lowest THR profile of 15.33 MJ/m−2. Additionally, Si compounds showed greater effectiveness in preventing ULDF mass loss than BF, NPF, and HF. MF showed the highest residual mass (40.94%). Furthermore, the synergistic effect between four FR agents showed more significant results in ULDFs.

  • 19.
    Chen, Tingjie
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Wu, Zhenzeng
    College of Material Engineering, Fujian Agricultural and Forestry University.
    Wei, Wei
    College of Material Engineering, Fujian Agricultural and Forestry Universit.
    Xie, Yongqun
    College of Material Engineering, Fujian Agricultural and Forestry Universit.
    Wei, Qihua
    College of Material Engineering, Fujian Agricultural and Forestry Universit.
    Wang, Alice
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Hagman, Olle
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Karlsson, Olov
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Optimizing Refining Conditions of Pinus massoniana Cellulose Fibers for Improving the Mechanical Properties of Ultra-Low Density Plant Fiber  Composite (ULD_UFC)2017In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 12, no 1, p. 8-18Article in journal (Refereed)
    Abstract [en]

    Response surface methodology was used to optimize the refining conditions of Pinus massoniana cellulose fiber and to improve the mechanical properties of ultra-low density plant fiber composite (ULD_PFC). The effects and interactions of the pulp consistency (X1), the number of passes (X2), and the beating gap (X3) on the internal bond strength of ULD_PFC were investigated. The results showed that the optimum internal bond strength (91.72 ± 2.28 kPa) was obtained under the conditions of 8.0% pulp consistency, two passes through the refiner, and a 30.0 μm beating gap. Analysis of the physical properties of the fibers and handsheets showed that the fibrillation of fibers with optimum refining conditions was improved. Also, the tear index of the optimal specimen was 13.9% and 24.5% higher than specimen-1 with a lowest beating degree of 24 oSR and specimen-6 with a highest beating degree of 73 oSR, respectively. Consequently, the optimal refining conditions of the fibers are valid for preparing ULD_PFCs.

  • 20.
    Chen, Tingjie
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering. tingjie.chen@ltu.se .
    Xie, Yongqun
    Department of Material Science and Engineering, Fujian Agriculture and Forestry University, Fuzhou.
    Wei, Qihua
    Department of Material Science and Engineering, Fujian Agriculture and Forestry University, Fuzhou.
    Wang, Alice
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Hagman, Olle
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Karlsson, Olov
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Liu, Jinghong
    Department of Material Science and Engineering, Fujian Agriculture and Forestry University, Fuzhou.
    Effect of Refining on Physical Properties and Paper Strength of Pinus massoniana and China Fir Cellulose Fibers2016In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 11, no 3, p. 7839-7848Article in journal (Refereed)
    Abstract [en]

    To obtain a suitable refining process for Pinus massoniana cellulose fibers (PMCF) and China fir cellulose fibers (CFCF), the effects of the beating gap and the pulp consistency on the physical properties and the morphology of the two cellulose fibers were investigated. The results showed that the physical properties of the PMCF and the CFCF were well affected by the beating gap and the pulp consistency. The CFCF showed a smaller weight-average length and width than that of the PMCF. The CFCF exhibited smaller weight-average length, width, and kink index than the PMCF. It is easy to get the high beating degree, indicating it is more easily to be refined. Additionally, the tensile index and burst index of PMCFP and CFCFP increased with increasing beating degree, while the tear index decreased. Compared to the CFCF, the paper made from PMCF had superior strength properties. Consequently, the PMCF was suitable for refining with a high pulp consistency and a medium beating gap, whereas the CFCF had a medium pulp consistency and a big beating gap.

  • 21.
    Chen, Tingjie
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Xie, Yongqun
    College of Material Engineering, Fujian Agriculture and Forestry University.
    Wei, Qihua
    College of Material Engineering, Fujian Agriculture and Forestry University.
    Wang, Xiaodong (Alice)
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Hagman, Olle
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Karlsson, Olov
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Liu, Jinghong
    College of Material Engineering, Fujian Agriculture and Forestry University.
    Lin, Ming
    College of Material Engineering, Fujian Agriculture and Forestry University.
    Improving the Mechanical Properties of Ultra-Low Density Plant Fiber Composite (ULD_PFC) by Refining Treatment2016In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 11, no 4, p. 8558-8569Article in journal (Refereed)
    Abstract [en]

    To improve the mechanical properties of ultra-low density plant fiber composite (ULD_PFC), a suitable beating process to improve the fibrillation of cellulose fibers and maintain their length was investigated. The physical properties of cellulose fibers and papers, surface chemical bonds, and internal bond strength (IB) of ULD_PFCs were analyzed. The results showed that the beating degrees, degree of fibrillation, and fiber fines increased with the decreasing of beating gap, except for the fiber weight-average length, width, kink index, and curl index. The tensile index and burst index of paper showed an increasing trend with an increase in beating degree, while the tear index showed a decreasing trend. FTIR results showed that intermolecular and intramolecular hydrogen bonds in ULDF were broken. A suitable beating gap of 30 μm with a beating degree of 35 °SR was obtained. The corresponding IB was 50.9 kPa, which represented an increase of 73.1% over fibers with a beating degree of 13 °SR.

  • 22. Cristescu, Carmen
    et al.
    Karlsson, Olov
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Changes in content of furfurals and phenols in self-bonded laminated boards2013In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 8, no 3, p. 4056-4071Article in journal (Refereed)
    Abstract [en]

    Pressing beech veneers at high temperatures has been shown to be a reliable method for manufacturing laminated boards without adhesives. The reasons behind the self-bonding phenomenon as well as the causes of the waterproof character gained by the boards being pressed at 250 degrees C were investigated. Water leachates from the dried and the hot-pressed veneers were analysed by UV-spectroscopy, high-performance liquid chromatography (HPLC), and solid-state cross-polarization magic angle spinning carbon-13 nuclear magnetic resonance (CP/MAS 13C NMR). Press-plate temperatures during hot pressing were 200, 225, and 250 degrees C. After pressing, an increased content of 5-(hydroxymethyl) furfural (not at 250 degrees C) and conjugated phenols was observed in the bonding lines (interfaces) compared to the inner part of veneers of the self-bonded boards. Furfural contents were low and relatively similar, but 5-(hydroxymethyl) furfural (HMF) showed an abrupt decrease in the bonding line when the temperature increased from 200 degrees C to 225 degrees C and especially to 250 degrees C. The contribution of caramelization to browning and bonding is suggested. In studies with CP/MAS 13C NMR, a higher content of phenolic units in beech lignin was observed during hot pressing at 225 degrees C. Homolytical cleavage of beta-O-4 structures in lignin as well as the condensation reactions involved are discussed

  • 23.
    Cristovao, Luis
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Ekevad, Mats
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Grönlund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Industrial Sawing of Pinus Sylvestris L.: Power consumption2013In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 8, no 4, p. 6044-6053Article in journal (Refereed)
    Abstract [en]

    The wood industry continues to strive to reduce production costs and increase productivity to remain competitive. Knowledge of the effect of wood cutting parameters on power consumption could increase energy efficiency, reducing operating costs and increasing profitability. Measuring power consumption also provides information about other variables, such as tool edge wear, occurrence of catastrophic failures, and other parameters that affect the quality of the sawn boards and the momentary efficiency of the breakdown process. In this work, power consumption during sawing of Pinus sylvestris L. using a double arbor circular saw was investigated. Both climb-sawing and counter-sawing were considered. The experiments were carried out under normal production circumstances in two Swedish sawmills. The relationship between cutting parameters and theoretical power consumption was investigated. The experimental power consumption increased by 11 to 35% during an 8-h shift, mainly due to an increase in the tooth radius. Additionally, this study showed that climb-sawing consumed more power than counter-sawing.

  • 24.
    Cristovao, Luis
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Ekevad, Mats
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Grönlund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Natural frequencies of roll-tensioned circular sawblades: Effects of roller loads, number of grooves and groove positions2012In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 7, no 2, p. 2209-2219Article in journal (Refereed)
  • 25.
    Duchesne, Isabelle
    et al.
    Natural Resources Canada, Canadian Wood Fibre Centre, Québec, QC, Canada.
    Vincent, Manon
    Ministère des Forêts, de la Faune et des Parcs du Québec, Québec, QC, Canada.
    Wang, Xiaodong (Alice)
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Ung, Chhun-Huor
    Natural Resources Canada, Canadian Wood Fibre Centre, Québec, QC, Canada.
    Swift, D. Edwin
    Natural Resources Canada, Canadian Wood Fibre Centre, Fredericton, NB, Canada.
    Wood Mechanical Properties and Discoloured Heartwood Proportion in Sugar Maple and Yellow Birch Grown in New Brunswick2016In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 11, no 1, p. 2007-2019Article in journal (Refereed)
    Abstract [en]

    Rising interest in using wood in non-residential multi-story building structures opens up new opportunities for utilising low-grade hardwoods. The primary objective of this study was to evaluate the geographic variation in modulus of elasticity (MOE) and modulus of rupture (MOR) of sugar maple and yellow birch wood in relation to stand and tree characteristics for two regions in New Brunswick, Canada. Mixed effects statistical models were developed to test the effects of stand, tree, and wood sample variables. A second objective was to examine geographic variation in heartwood discolouration in relation to stand and tree characteristics. Between-tree differences (trees nested within sites) accounted for 44% and 35% of the total variation in yellow birch (MOE and MOR, respectively) and for 69% and 60% of total variation in sugar maple. The fixed effects explained only a very small part for the variation in MOE and MOR in the sugar maple data (10% for MOE and 5% for MOR). For sugar maple, mechanical properties (MOE and MOR) at 50% of the radius were considerably lower than those close to the bark, but this radial variation was not noteworthy for yellow birch. Discoloured heartwood proportion had no significant effect on wood mechanical properties.

  • 26.
    Ekevad, Mats
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Axelsson, Ann
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Variation of modulus of elasticity in the tangential direction with moisture content and temperature for Norway Spruce (Picea abies)2012In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 7, no 4, p. 4730-4743Article in journal (Refereed)
    Abstract [en]

    Modulus of elasticity (MOE) in the tangential direction for Norway spruce, Picea abies (L.) H.Karst was measured. Test samples were tested in three-point bending, and moisture content (MC) and temperature were varied between the green condition and 7% MC and between 20°C and 80°C, respectively. An adjustment of measured MOE to the ideally tangential direction was made by using correction factors calculated from finite element simulations. The results show MOE and the gradients with respect to MC and temperature and how they vary with MC and temperature. The gradients are factors in gradient terms in the incremental stress-strain relation for linear elastic behaviour during load cycles where there are mechanical loads and at the same time varying MC and temperature. The gradient terms add to the temperature and MC expansion coefficients and may be of significant size for cases with high stress, high temperature and high MC.

  • 27.
    Elustondo, Diego
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Myronycheva, Olena
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Sundqvist, Bror
    SP Technical Research Institute of Sweden.
    Karlsson, Olov
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Localized Wood Surface Modification: Part I: Method Characterization2016In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 12, no 1, p. 283-295Article in journal (Refereed)
    Abstract [en]

    This study assesses the potential of an open process for treatment of European Scots pine (Pinus sylvestris) with chemicals that could potentially make the surfaces stronger, more dimensionally stable, or more durable, depending on the treatment solution. The method provides an intermediate solution between full volume impregnation by pressure treatment and superficial surface treatment by dipping. Figuratively speaking, the process creates the equivalent of a layer of coating applied below the wood surfaces rather than above. Two different techniques were compared, namely, heating-and-cooling (H&C) and compression-and-expansion (C&E). Taking into account that commercial suppliers recommend 0.15 to 0.25 L/m2 of coating in sawn wood and 0.1 to 0.15 L/m2 in planed wood surfaces, then this study demonstrates that the H&C method can impregnate an equivalent amount of solution under the surfaces in less than 15 min using treatment temperatures below 150 °C.

  • 28.
    Farzaneh, Amirfarrokh
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Richards, Tobias
    University of Borås.
    Heiningen, Adrian van
    Aalto University, Espoo.
    Sklavounos, Evangelos
    Aalto University, Espoo.
    A Kinetic Study of CO2 and Steam Gasification of Char from Lignin Produced in the SEW Process2014In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 9, no 2, p. 3052-3063Article in journal (Refereed)
    Abstract [en]

    The reaction kinetics of gasification are important for the design of gasifiers using biomass feedstocks, such as lignin, produced in biorefinery processes. Condensed and uncondensed lignin samples used in the present study were prepared using the SEW (SO2-ethanol-water) fractionation process applied to spruce wood chips: the dissolved lignin is precipitated during the recovery of SO2 and ethanol from the spent fractionation liquor. The gasification of char made from condensed and uncondensed SEW lignin was investigated using thermogravimetric analysis (TGA) at atmospheric pressure using either CO2 or steam. The main aim of this study was to quantify the reaction rate during the gasification process, which was found to be best described as zero-order. All experiments were performed at constant temperatures between 700 and 1050 °C to obtain the necessary information for describing the reaction rate equation in an Arrhenius form; the heating rate was 20 °C/min for both samples. The experiments led to almost similar results for both samples. The activation energies of CO2 gasification were approximately 160 kJ/mol and 170 kJ/mol for uncondensed and condensed lignin char, respectively. The activation energies of steam gasification were approximately 90 kJ/mol and 100 kJ/mol for uncondensed and condensed lignin char, respectively.

  • 29.
    Fredriksson, Magnus
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Bomark, Peter
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Broman, Olof
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Grönlund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Using Small Diameter Logs for Cross Laminated Timber Production2015In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 10, no 1, p. 1477-1486Article in journal (Refereed)
    Abstract [en]

    Sawing small diameter logs results in lower yield compared to sawing large diameter logs. This is due to geometry; fitting rectangular blocks inside an approximately cylindrical shape is more difficult for small than for large diameters. If small diameter logs were sawn in a way that follows the outer shape, yield would increase. The present study considers whether this can be done by sawing flitches into trapeze shapes. These can be glued together into rectangular products. Cross laminated timber (CLT) products are suitable for this. The study was based on 4,860 softwood logs that where scanned, and the scanning data was used for sawing simulation. The log top diameters ranged from 92 to 434 mm. The volume yield of CLT production using trapeze edging was compared to cant sawing of boards. The trapeze edging and CLT production process improved yield compared to cant sawing by 17.4 percent units, for logs of a top diameter smaller than 185 mm. For all logs, the yield decreased using the trapeze edging method. To conclude, a trapeze edging method shows promise in terms of increasing volume yield for small diameter logs, if boards can be properly taken care of in a CLT production process

  • 30.
    Fredriksson, Magnus
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Johansson, Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Berglund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Rotating Pinus sylvestris sawlogs by projecting knots from computed tomography images onto a plane2014In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 9, no 1, p. 816-827Article in journal (Refereed)
  • 31.
    Guo, Xiaolei
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Ekevad, Mats
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Grönlund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Marklund, Birger
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Cao, Pingxiang
    Nanjing Forestry University.
    Tool wear and machined surface roughness during wood flour/polyethylene composite peripheral upmilling using cemented tungsten carbide grades2014In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 9, no 3, p. 3779-3791Article in journal (Refereed)
    Abstract [en]

    The effect of sharpness angle on tool wear and the effect of tool wear on machined surface roughness were investigated in wood flour/polyethylene composite (WFPEC) peripheral up-milling using cemented tungsten carbide (TC) tools. It was shown that nose width and edge recession increased with increasing feeding length. During the milling process, the wear of the nose width was smallest for the tool with a sharpness angle of 45°, followed by tools with sharpness angles of 55° and 65°. The wear of edge recession was highest for the tool with a sharpness angle of 45°, followed by tools with sharpness angles of 55° and 65°. The nose width increased with increasing sharpness angle, the edge recession decreased with increasing sharpness angle, and the machined surface roughness increased with increasing sharpness angle after a feeding length of 40 m. The nose width had a positive effect on the machined surface roughness, and the machined surface roughness increased with increasing nose width. The edge recession had little effect on the machined surface roughness. The clearance face roughness of the worn tool increased with increasing sharpness angle. The analysis of the SEM micrographs and EDS of the clearance face of the worn tool showed that the wear mechanisms of the cemented tungsten carbide tool were oxidation and abrasion in the range tested during cutting. Thus, a slight wear of the edge recession is gained in exchange for a lower machined surface roughness by decreasing the sharpness angle.

  • 32.
    Guo, Xiaolei
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Ekevad, Mats
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Marklund, Birger
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Li, Rongrong
    Nanjing Forestry University.
    Cao, Pingxiang
    Nanjing Forestry University.
    Grönlund, Anders
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Cutting Forces and Chip Morphology during Wood Plastic Composites Orthogonal Cutting2014In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 9, no 2, p. 2090-2106Article in journal (Refereed)
  • 33.
    Guo, Xiaolei
    et al.
    Nanjing Forestry University, College of Material Science and Engineering.
    Lin, Yubin
    Nanjing Forestry University, College of Material Science and Engineering.
    Na, Bin
    Nanjing Forestry University, College of Material Science and Engineering.
    Liang, Xingyu
    Nanjing Forestry University, College of Material Science and Engineering.
    Ekevad, Mats
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Ji, Futang
    Nanjing Forestry University, College of Material Science and Engineering.
    Huang, Lingling
    Nanjing Forestry University, College of Material Science and Engineering.
    Evaluation of physical and mechanical properties of fiber-reinforced poplar scrimber2017In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 12, no 1, p. 43-55Article in journal (Refereed)
    Abstract [en]

    The mechanical properties of poplar scrimber reinforced with glass fiber mesh were investigated. The influence of the different structures and densities were studied with respect to the modulus of rupture (MOR), modulus of elasticity (MOE), and impact toughness (IT). The glass fiber improved the mechanical properties of poplar scrimber. The MOR, MOE, and IT of the scrimber had an obvious dependence on the number of glass fiber layers. When the layers of glass fiber meshes were increased, the MOR, MOE, and IT were increased compared to the control group (scrimber without glass fiber reinforcement). The MOR, MOE, and IT of single-layer glass fiber reinforced scrimber increased a lot compared to the control group. The MOR, MOE, and IT of double-layer glass fiber reinforced scrimber (DGRS) were increased, but the amplitude of the increase was smaller than that of SGRS. Compared to the MOR, MOE, and IT of DGRS, the MOR, MOE, and IT of triple-layer glass fiber reinforced scrimber (TGRS) decreased slightly. When the density was increased, the increasing rate of the MOR, MOE, and IT of the glass fiber reinforced scrimber showed a downward trend, and the glass fiber had better strengthen effects on the scrimber at low density (0.6 g/cm3 and 0.7 g/cm3).

  • 34.
    He, Guojing
    et al.
    Department of Civil Engineering and Mechanics, Central South University of Forestry and Technology.
    Xie, Lan
    Department of Civil Engineering and Mechanics, Central South University of Forestry and Technology.
    Wang, Xiaodong (Alice)
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Yi, Jin
    Department of Civil Engineering and Mechanics, Central South University of Forestry and Technology.
    Peng, Lening
    Department of Civil Engineering and Mechanics, Central South University of Forestry and Technology.
    Chen, Zi'ang
    Department of Civil Engineering and Mechanics, Central South University of Forestry and Technology.
    Gustafsson, Per Johan
    Division of Structural Mechanics, Lund University.
    Crocetti, Roberto
    Division of Structural Mechanics, Lund University.
    Shear Behavior Study on Timber-Concrete Composite Structures with Bolts2016In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 11, no 4, p. 9205-9218Article in journal (Refereed)
    Abstract [en]

    The key point of design for timber-concrete composite structure is to ensure the reliability of shear connectors. This study examined the mechanical properties of bolt-type connectors in timber-concrete composite structures theoretically and experimentally. The theoretical study was based on the Johansen yield theory (European Yield Model). Push-out specimens with different bolt dimensions were tested to determine the shear capacity and slip modulus. According to the experimental results, bolts yielded without timber or concrete cracks when the stiffness of bolts was not very great. The shear capacity and slip modulus of the bolt connectors were directly proportional to the diameter of the bolt. The strength of concrete was found to significantly affect the shear capacity of bolt connectors. Comparison between the theoretical and the experimental shear strength results showed reasonable agreement. 

  • 35.
    Hietala, Maiju
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Niinimäki, Jouko
    University of Oulu.
    Oksman, Kristiina
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    The use of twin-screw extrusion in processing of wood: The effect of processing parameter and pretreatment2011In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 6, no 4, p. 4615-4625Article in journal (Refereed)
    Abstract [en]

    In this study the effect of processing parameters on different types of wood raw material in extrusion was examined. The study consisted of two parts: the first part was to break and separate individual fibers from wood chips during the extrusion process; in the second part the effect of chemical pre-treatment and screw elements on wood raw material was evaluated. Statistical analysis was performed to evaluate the most important factors affecting wood particle size in extrusion. The statistical analysis showed that the screw speed is the main factor affecting wood fiber length in twin-screw extrusion of wood chips. This study showed that a twin-screw extruder can be used to separate individual fibers from wood chips, and the separated fibers have higher aspect ratios than the wood flour particles typically used in wood-polymer composites. When more fibrous and chemically softened wood raw material was used, fibers with even higher aspect ratios were obtained.

  • 36.
    Jonoobi, Mehdi
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Harun, Jalaludin
    University of Putra Malaysia.
    Mishra, Manju
    University of Guelph.
    Oksman, Kristiina
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Chemical composition, crystallinity and thermal degradation of bleached and unbleached kenaf bast (Hibiscus cannabinus) pulp and nanofiber2009In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 4, no 2, p. 626-639Article in journal (Refereed)
    Abstract [en]

    Kenaf (Hibiscus cannabinus) nanofibers were isolated from unbleached and bleached pulp by a combination of chemical and mechanical treatments. The chemical methods were based on NaOH-AQ (anthraquinone) and three-stage bleaching (DEpD) processes, whereas the mechanical techniques involved refining, cryo-crushing, and high-pressure homogenization. The size and morphology of the obtained fibers were characterized by environmental scanning electron microscopy (ESEM) and transmission electron microscopy (TEM), and the studies showed that the isolated nanofibers from unbleached and bleached pulp had diameters between 10-90 nm, while their length was in the micrometer range. Fourier transform infrared (FTIR) spectroscopy demonstrated that the content of lignin and hemicellulose decreased in the pulping process and that lignin was almost completely removed during bleaching. Moreover, thermogravimetric analysis (TGA) indicated that both pulp types as well as the nanofibers displayed a superior thermal stability as compared to the raw kenaf. Finally, X-ray analyses showed that the chemo-mechanical treatments altered the crystallinity of the pulp and the nanofibers: the bleached pulp had a higher crystallinity than its unbleached counterpart, and the bleached nanofibers presented the highest crystallinity of all the investigated materials.

  • 37.
    Karlsson, Olov
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Sehlstedt-Persson, Margot
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Morén, Tom
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Yang, Qian
    Heat treatments of high temperature dried norway spruce boards: Saccharides and furfurals in sapwood surfaces2012In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 7, no 2, p. 2284-2299Article in journal (Refereed)
    Abstract [en]

    Carbohydrates that migrate to wood surfaces in sapwood during drying might influence properties such as mould susceptibility and colour. Sugars on the surface of Norway spruce boards during various heat treatments were studied. Samples (350mm×125mm×25mm) were double-stacked, facing sapwood-side outwards, and dried at 110°C to a target moisture content (MC) of 40%. Dried sub-samples (80 mm × 125 mm × 25 mm) were stacked in a similar way and further heated at 110°C and at 130°C for 12, 24, and 36 hours, respectively. Glucose, fructose, and sucrose as well as 5-hydroxymethylfurfural (HMF) and furfural in the sapwood surface layer of treated wood were analysed using HPLC (RI- and UV-detectors). Carbohydrates degraded to a lower extent at 110°C than at 130°C. Furfural and to a larger extent HMF increased with treatment period and temperature. Heat treatment led to a decrease in lightness and hue of the sapwood surface of sub-samples, while chroma increased somewhat. Furthermore, considerably faster degradation (within a few minutes) of the carbohydrates on the surface of the dried spruce boards was observed when single sub-samples were conductively hot pressed at 200°C. Treatment period and initial MC influenced the presence of the carbohydrates in wood surface as well as colour change (ΔE ab) of the hot pressed sub-samples.

  • 38.
    Karlsson, Olov
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Sidorova, Ekaterina
    SP Technical Research Institute of Sweden.
    Morén, Tom
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Influence of heat transferring media on durability of thermally modified wood2011In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 6, no 1, p. 356-372Article in journal (Refereed)
    Abstract [en]

    Studies on the durability and dimensional stability of a series of hardwoods and softwoods after thermal modification in vegetable oils and in steam atmospheres have been performed. Mass loss after exposure to Coniophora puteana (BAM Ebw. 15) for 16 weeks was very low for European birch, European aspen, Norway spruce, and Scots pine thermally modified in a linseed oil product with preservative (for 1 hour at 200 degrees C). Fairly low mass losses were obtained for wood thermally modified in linseed-, tung-and rapeseed oil, and losses were related to the wood species. Low mass loss during rot test was also found for Norway spruce and Scots pine modified in saturated steam at 180 degrees C. Water absorption of pine and aspen was reduced by the thermal treatments and the extent of reduction was dependent on wood species and thermal modification method. Thermally modified aspen was stable during cycling climate tests, whereas pine showed considerable cracking when modified under superheated steam conditions (Thermo D). At lower modification temperature (180 degrees C) an increase in mass after modification in rapeseed oil of spruce, aspen and sapwood as well as heartwood of pine was observed, whereas at high temperature (240 degrees C) a mass loss could be found. Oil absorption in room tempered oil after thermal modification in oil was high for the more permeable aspen and pine (sapwood).

  • 39.
    Karlsson, Olov
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Torniainen, Petteri
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Dagbro, Ola
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Granlund, Kurt
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Morén, Tom
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Presence of water-soluble compounds in thermally modified wood: carbohydrates and furfurals2012In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 7, no 3, p. 3679-3689Article in journal (Refereed)
    Abstract [en]

    With thermal modification, changes in properties of wood, such as the presence of VOC and water-soluble carbohydrates, may occur. Thermal modifications under saturated steam conditions (160°C or 170°C) and superheated steam conditions (170, 185, and 212°C) were investigated by analysing the presence of water-soluble 5-(hydroxymethyl)furfural (HMF), furfural, and carbohydrates in heat-treated wood. The influence of thermal modifications on Scots pine, Norway spruce, and silver birch was also studied. Furfurals were analysed using HPLC at 280 nm, while monosaccharides and water-soluble carbohydrates were determined by GC-FID as their acetylated alditiols and, after methanolysis, as their trimethylsilylated methyl-glycosides, respectively. The amount of furfurals was larger in boards thermally modified under saturated steam conditions than those treated under superheated steam conditions. Generally, more of HMF than furfural was found in the thermally modified boards. In process water, in which saturated steam conditions had been used, furfural and only traces of HMF were found. Higher content of water-soluble carbohydrates was found in boards treated in saturated steam rather than in superheated steam. After modification in saturated steam, substantial parts of the water-soluble carbohydrates were due to monosaccharides, but only traces of monosaccharides were found in boards treated under superheated steam conditions.

  • 40.
    Li, Rongrong
    et al.
    Nanjing Forestry University, College of Furnitures & Industrial Design, Nanjing.
    Cao, Pingxiang
    Nanjing Forestry University, College of Material Science & Engineering, Nanjing.
    Xu, Wei
    Nanjing Forestry University, College of Furnitures & Industrial Design, Nanjing.
    Ekevad, Mats
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Wang, Alice
    Department of Wood and Forest Sciences, Laval University.
    Experimental and Numerical Study of Moisture-induced Stress Formation in Hexagonal Glulam Using X-ray Computed Tomography and Finite-element Analysis2018In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 13, no 4, p. 7395-7403Article in journal (Refereed)
    Abstract [en]

    Hexagonal glue-laminated timber with large cross-sections, made from small diameter logs, was studied. Effects of relative humidity variations on the moisture-induced stresses were investigated to evaluate how the prediction model compared to a real outcome. The test samples were exposed to an environment with relative humidity variations from 80% to 30%. The moisture content inside the samples was measured via X-ray computed tomography scanning. A moisture transport and a hygromechanical finite element simulation model was used for the prediction of moisture content and resulting stress distribution. The results from both the test and simulation showed that the moisture content in the edge angles of the samples dropped rapidly due to a large moisture diffusion rate. The moisture gradient was generated via a different moisture transfer rate at the inner and external parts of the samples. The maximum stress perpendicular to the grain in the simulation was 8 MPa and was located at the surface near the corners. This stress peak caused cracking according to the model, which was also seen in the test samples. The results for the measured moisture content agreed with the simulated results and this indicated that the moisture transfer model was adequate for simulation.

  • 41.
    Li, Rongrong
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering. Nanjing Forestry University.
    Ekevad, Mats
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Guo, Xiaolei
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering. Nanjing Forestry University.
    Cao, Pingxiang
    Nanjing Forestry University.
    Wang, Jie
    Nanjing Forestry University.
    Chen, Qingqing
    Nanjing Forestry University.
    Xue, Hong
    Nanjing Forestry University.
    Pressure, Feed Rate, and Abrasive Mass Flow Rate Influence on Surface Roughness for Recombinant Bamboo Abrasive Water Jet Cutting2015In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 10, no 2, p. 1998-2008Article in journal (Refereed)
    Abstract [en]

    The effects of pressure, feed rate, and abrasive mass flow rate on surface roughness were investigated during abrasive water cutting of recombinant bamboo. Two different thicknesses (10 mm and 15 mm) of recombinant bamboo were cut in the longitudinal and transversal directions by abrasive water jet. All experiments were arranged using response surface methodology. The parameter Ra was selected to represent the surface roughness. The value of Ra increased with an increase in feed rate and abrasive mass flow rate, but decreased with an increase in pressure. The surface roughness was lower when cutting the fiber longitudinally than when cutting transversally.

  • 42.
    Li, Rongrong
    et al.
    Nanjing Forestry University.
    Ekevad, Mats
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Guo, Xiaolei
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering. Nanjing Forestry University.
    Ding, Jianwen
    Nanjing Forestry University.
    Cao, Pingxiang
    Nanjing Forestry University.
    Effect of Pressure, Feed Rate, and Abrasive Mass Flow Rate on Water Jet Cutting Efficiency When Cutting Recombinant Bamboo2015In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 10, no 1, p. 499-509Article in journal (Refereed)
    Abstract [en]

    Recombinant bamboo with a thickness of 15 mm was drilled on a CNC machine. The process parameters considered were spindle speed, feed rate, and diameter of the drill, and the response parameters were thrust force and torque. Mathematical models were developed to establish the relationship between the process parameters and the response parameters. The results showed that the main influence on thrust force came from spindle speed and feed rate. High spindle speed with low feed rate was a combination that minimized the thrust force. The process parameters that have a major effect on torque are the diameter of the drill and the spindle speed.

  • 43.
    Li, Rongrong
    et al.
    Nanjing Forestry University.
    Ekevad, Mats
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Wang, Jie
    Nanjing Forestry University.
    Guo, Xiaolei
    Nanjing Forestry University.
    Cao, Pingxiang
    Nanjing Forestry University.
    Testing and Modeling of Thrust Force and Torque in Drilling Recombinant Bamboo2014In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 9, no 4, p. 7326-7335Article in journal (Refereed)
  • 44.
    Li, Rongrong
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Guo, Xiaolei
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Ekevad, Mats
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Marklund, Birger
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Cao, Pingxiang
    Faculty of Material Science and Engineering. Nanjing Forestry University.
    Investigation of Glueline Shear Strength of Pine Wood Bonded with PVAc by Response Surface Methodology2015In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 10, no 3, p. 3831-3838Article in journal (Refereed)
  • 45.
    Liu, Jinghong
    et al.
    College of Material Engineering, Fujian Agriculture and Forestry University.
    Chen, Tingjie
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering. College of Material Engineering, Fujian Agriculture and Forestry University.
    Xie, Yongqun
    College of Material Engineering, Fujian Agriculture and Forestry University.
    Wei, Qihua
    College of Material Engineering, Fujian Agriculture and Forestry University.
    Chen, Yan
    College of Material Engineering, Fujian Agriculture and Forestry University.
    Rao, Jiuping
    College of Material Engineering, Fujian Agriculture and Forestry University.
    Niu, Min
    College of Material Engineering, Fujian Agriculture and Forestry University.
    Wang, Xiaodong (Alice)
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Fire Performance of Ultra-Low Density Fiberboard (ULDF) with Complex Fire-Retardants2016In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 11, no 4, p. 10261-10272Article in journal (Refereed)
    Abstract [en]

    To clarify how the fire performance of ultra-low density fiberboard (ULDF) can be improved by complex fire-retardants, the limiting oxygen index (LOI) and microstructure of ULDFs with different additive amounts of complex fire-retardants was analyzed. The char yield, chemical bonding, and thermostability of ULDFs treated by different temperatures were also tested. Results showed that the LOI values and compactness of ULDFs were increased with increased amounts of fire-retardants. Three steps of char yield curves in control fiberboard (CF) and mixed fiberboard (MF) were apparent. The preliminary degradation in lignin and cellulose of CF occurred at 300 °C. The cellulose had completely decomposed at 400 °C, but in the case of MF, the lignin and cellulose were not completely decomposed at 400 °C. It was shown that there are different ways to improve the fire resistance of ULDF using boron, nitrogen-phosphorus, silica, and halogen-based fire-retardants. The fiberboard with silicium compounds had the lowest mass loss in three stages and total mass loss. Compared with CF, MF had a lower mass loss. Furthermore, the exothermic peak for MF at around 400.0 °C was decreased, indicating that the fire resistance of ULDF was improved by the complex fire-retardants. 

  • 46.
    Liu, Xiaomei
    et al.
    Mississippi State University, Department of Sustainable Bioproducts, Mississippi.
    Wu, Yiqiang
    Central South University of Forestry and Technology, School of Materials Science and Engineering, Changsha, China.
    Shmulsky, Rubin
    Mississippi State University, Department of Sustainable Bioproducts, Mississippi.
    Luo, Yan
    Mississippi State University, Department of Sustainable Bioproducts, Mississippi.
    Wang, Xiaodong (Alice)
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Chu, I wei
    Institute for Imaging and Analytical Technologies, Mississippi State University, Mississippi State.
    Wan, Hui
    Mississippi State University, Department of Sustainable Bioproducts, Mississippi.
    Developing a Renewable Hybrid Resin System: Part I: Characterization of Co-Polymers of Isocyanate with Different Molecular Weights of Phenolic Resins2016In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 11, no 2, p. 5299-5311Article in journal (Refereed)
    Abstract [en]

    Co-polymer systems of methylene diphenyl diisocyanate (MDI) and phenol-formaldehyde (PF) resins with different molecular weights were characterized by infrared spectroscopy (FTIR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The FTIR and TGA coupled with differential thermogravimetric (DTG) results showed that higher molecular weight of PF resins not only promoted the reaction of isocyanate and PF co-polymer system, but also resulted in a better thermal property of prepared co-polymers. The XRD results revealed that higher molecular weight led to a higher proportion of ordered or crosslinking structures in the hybrid resin system. The relationship between the thermal resistance, mechanical properties and the molecular weights of phenolic resins needs further study.

  • 47.
    Matsakas, Leonidas
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Antonopoulou, Io
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Christakopoulos, Paul
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Evaluation of Myceliopthora thermophila as an enzyme factory for the production of thermophilic cellulolytic enzymes2015In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 10, no 3, p. 5140-5158Article in journal (Refereed)
    Abstract [en]

    Enzymatic hydrolysis is a key step in bioethanol production. Efficient hydrolysis requires a consortium of different enzymes that are able to hydrolyze cellulose and hemicellulose into fermentable sugars. Myceliopthora thermophila is a promising candidate for the production of thermophilic cellulolytic enzymes, the use of which could reduce the cost of ethanol production. The growth conditions of the fungus were optimized in order to achieve increased secretion of extracellular cellulases. Optimal conditions were found to be 7.0% w/v brewer’s spent grain as the carbon source and 0.4% w/v ammonium sulfate as the nitrogen source. The cellulases obtained were characterized for their optimum activity. The optimum temperature and pH for cellulase activity are 65 °C and pH 5.5, respectively. Studies on thermal inactivation of the crude extract showed that the cellulases of M. thermophila are stable for temperatures up to 60 °C. At this temperature the half-life was found to be as high as 27 h. Enzymatic hydrolysis of cellulose resulted in 31.4% hydrolysis yield at 60 °C after 24 h of incubation. Finally, the recalcitrance constant for cellulose and cellulose pretreated with ionic liquids was calculated to be 5.46 and 2.69, respectively.

  • 48.
    Matsakas, Leonidas
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Rova, Ulrika
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Christakopoulos, Paul
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Strategies for Enhanced Biogas Generation through Anaerobic Digestion of Forest Material: An Overview2016In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 11, no 2, p. 5482-5499Article in journal (Refereed)
    Abstract [en]

    Incorporation of biofuels into the existing selection of fuels is a very important measure to slow down environmental destruction and to counter the imminent fossil fuel shortage. Biogas is a very interesting option for use in both electricity and heat production, and also as a fuel for vehicles. The positive fuel characteristics of biogas and the high yields of biogas obtained from traditional raw materials (e.g., animal manure) have resulted in operation of several commercial units around the globe. On the other hand, there is an increased demand for biogas production which, for the need to be met, should have renewable resources incorporated into it. Forest materials are an interesting candidate, and there is a rising interest in the research and industrial communities to exploit them as raw materials for anaerobic digestion in biogas production. In this review article, we aim to give the reader an insight into the most recent processes for conversion of various sources of forest materials into biogas.

  • 49.
    Myronycheva, Olena
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Bandura, Iryna
    Department of Technology Processing and Storag e of Agricultural Products, Tavria State Agrotecnological University.
    Bisko, Nina
    Department of Mycology, Institute of Botany, National Academy of Sciences of Ukraine.
    Grygansky, Andrii P.
    LF Lambert Spawn Co..
    Karlsson, Olov
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Assessment of the Growth and Fruiting of 19 Oyster Mushroom Strains for Indoor Cultivation on Lignocellulosic Wastes2017In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 12, no 3, p. 4606-4626Article in journal (Refereed)
    Abstract [en]

    AbstractTwelve Pleurotus ostreatus (Jacq. ex Fr.) P. Kumm and six Pleurotus pulmonarius (Fr.) Quél. strains were characterized from the National Culture Collection of Mushrooms, Institute of Botany Kholodny, National Academy of Science, Kyiv, Ukraine (IBK). The strains were grown under commercial conditions on a mixture of wheat straw and sunflower shells under both winter and summer temperatures typical for those climatic conditions. The strains were divided into three groups according to their growing patterns. Important characteristics were compared with a commercial analogue, HK-35, such as vegetative growth, generative growth, and biological efficiency (1.9- to 3.1-fold), and were recorded for strains 2251, 2292, 2316, 2319, and 2320 of P. ostreatus and 2314 of P. pulmonarius. Strains 2251, 2292, 2301, 2321 and 2323 were the most suitable for commercial production, while strains 2319 and 2320 could satisfy processing industry requirements with their high biological efficiency. Strains 2287 and 2317 produced high-quality fruit bodies but probably required a higher temperature for cultivation. Strain 2318 might be attractive for some consumers due to its unique and unusual fruit body shape. Strain 2314 was the most promising for summer cultivation, while strain 537 produced the highest quality fruit bodies.KeywordsOyster mushroom; Strain; Vegetative growth; Fruit body; Biological efficiency; Conversion Factor (CF); Asymmetry of the Fruit Body Cap (Cas)

  • 50.
    Myronycheva, Olena
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Sehlstedt-Persson, Margot
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Karlsson, Olov
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Sandberg, Dick
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Growth of mold and rot fungi on copper-impregnated Scots pine sapwood: Influence of planing depth and inoculation pattern.2018In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 13, no 4, p. 8787-8801Article in journal (Refereed)
    Abstract [en]

    The biocidal properties of an industrially used copper-based preservative were evaluated at different planing depths on exposure of pine wood to mold fungi in direct and indirect contamination methods, with simultaneous verification of white rot fungi virulence on wood. The preservative was an aqueous solution of copper carbonate, 2-aminoethanol, and quaternary ammonium compounds. Full cell preservative impregnation efficiency against visual mold fungi growth was tested on sapwood surfaces planed to different depths before impregnation. The virulence of two white rot fungal strains of Trametes versicolor (441 and JPEI) against the dried non-impregnated and impregnated wood samples was also tested. The unplaned surface of impregnated timber was occupied by air-borne contaminants, such as Paecilomyces variottiand Aspergillus niger up to 30%, and, even after impregnation it was necessary to process the surface to avoid micro-fungi settlement. The virulence of the tested rot fungi strains was confirmed by the aggressive degradation of non-impregnated wood with a mass loss of over 40%. Both Trametes sp. strains degraded the preservative-impregnated wood with a mass loss of 3.1% to 4.8%, but degradation by the JPEI strain was more intensive and more dependent on planing depth than the other strain (441).

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