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  • 51.
    Niu, Min
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknologi.
    Hagman, Olle
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknologi.
    Wang, Alice
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknologi.
    Xie, Yongqun
    Fujian Agriculture and Forestry University, Department of Wood Science & Technology.
    Karlsson, Olov
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknologi.
    Cai, LiLi
    Fujian Agriculture and Forestry University, Department of Wood Science & Technology.
    Effect of Si-Al compounds on fire properties of ultra-low density fiberboard2014Inngår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 9, nr 2, s. 2415-2430Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    An ultra-low density fiberboard was made of plant fiber using a liquid frothing approach. The inflammability of the plant fiber limited its application as a candidate for building insulation materials and packaging buffering materials. Si-Al compounds were introduced into the foaming system because of the high temperature resistance of Si and Al compounds. The results from energy-dispersive spectroscopy suggested that the Si and Al relatively evenly covered the surface of the fibers, and their weight ratios in the material increased as a function of the amount of Si-Al compounds. The increasing weight ratios of Si and Al affected the fire properties of the material, reducing the released amount of heat, smoke, and off-gases such as CO and CO2, as well as decreasing the mass loss percentage, shown through the use of a Cone Calorimeter. It follows that Si-Al compounds have an evident collaborative effect on the halogen fire retardant. The system can effectively restrain the fire hazard intensity and the yields of solid and gas volatiles.

  • 52.
    Niu, Min
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknik.
    Wang, Xiaodong (Alice)
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknik.
    Hagman, Olle
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknik.
    Karlsson, Olov
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknik.
    Xie, Yongqun
    Fujian Agriculture and Forestry University.
    Microstructure of Burned Ultra-Low-Density Fiberboards using Plant Fiber as the Matrix and Si-Al compounds as the Filler2015Inngår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 10, nr 2, s. 2903-2912Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Ultra-low-density fiberboards (ULDFs) were prepared by a liquid frothing technique using plant fibers as the matrix and Si-Al compounds as the filler to be used as a versatile bio-based composite. Si-Al compounds played an important role in the fire properties of ULDFs. Fire intensity and the amount of volatiles were significantly restrained because of the Si-Al compounds. To determine the combustion mechanism of ULDFs treated by Si-Al compounds, the microstructure of burned specimens was tested by chemical analysis, X-ray diffractometer (XRD), and infrared spectrometer (IR). According to the results from gas chromatography, glucose, xylose, and mannose disappeared in the bottom ashes. After combustion, the XRD profiles of the two ashes became weaker and broader; the sharpest peaks at 18.6o (2) that represented Si-Al compounds remained; the obvious peaks at 22o (2) from cellulose were gone. The results from IR suggested the characteristic functional groups OH, CH, and C=O from carbohydrate also disappeared, and absorbance at 1200 to 400 cm-1, which attributed to the vibration of Si-O, Al-O, and Si- O-Si bonds, increased. In conclusion, fibers are almost completely pyrolyzed at 780 °C. The crystalline structure of Si-Al compounds is rearranged and more amorphous silicon oxide and aluminum oxide are generated.

  • 53.
    Niu, Min
    et al.
    Fujian Agriculture and Forestry University, Fuzhou, China.
    Wang, Xiaodong (Alice)
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknik.
    Hagman, Olle
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknik.
    Karlsson, Olov
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknik.
    Xie, Yongqun
    Fujian Agriculture and Forestry University.
    Morphology of Burned Ultra-low Density Fiberboards2015Inngår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 10, nr 4, s. 7292-7301Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The synergistic effect of two fire retardants, a Si-Al compound and chlorinated paraffin, was tested on ultra-low density fiberboards (ULDFs). To further understand the mechanism of fire retardancy, morphologies of unburned and burned ULDFs were studied using a scanning electron microscope with energy dispersive spectroscopy. It was found that as the volume of the burned ULDFs shrank, some crevices appeared. In addition, less fly ash formed on the top of specimens, and more bottom ashes remained in the original framework, with a clear network of structure built by the fibers. Carbon was almost absent in the fly ash; however, the weight ratio of C in the bottom ashes reached the maximum (> 43%) of the composition. Oxygen, Al, and Si appeared to have varying weight ratios for different ashes. Oxygen content increased with increasing Si and Al contents. Furthermore, Cl sharply decreased to less than 1% after combustion. Therefore, upon combustion, it was found that almost all of the substances in ULDFs, except for the Si-Al compound, were pyrolyzed to volatile carbon oxides and Cl compounds, especially the fly ash and lightweight C compounds.

  • 54.
    PM, Visakh
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Thomas, S.
    Centre for Nanoscience and Nanotechnology, Mahatma Gandhi University, Kottayam, Kerala.
    Oksman, Kristiina
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Mathew, Aji P.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Effect of cellulose nanofibers isolated from bamboo pulp residue on vulcanized natural rubber2012Inngår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 7, nr 2, s. 2156-2168Artikkel i tidsskrift (Fagfellevurdert)
  • 55.
    Porankiewicz,, Bolesław
    et al.
    University of Zielona Góra.
    Marklund, Birger
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknologi.
    Grönlund, Anders
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknologi.
    Axelsson, Bengt
    Main and normal cutting forces by machining wood of Pinus Sylvestris2011Inngår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 6, nr 4, s. 3687-3713Artikkel i tidsskrift (Fagfellevurdert)
  • 56.
    Ramberg, David
    et al.
    Lulea University of Technology, Skelleftea.
    Jeppson, Per
    Former students at Building Engineering, Lund University, Lund, Sweden.
    Wang, Xiaodong (Alice)
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknik.
    Simulation of Relative Humidity and Temperature and Modeling of Mold Growth in Exterior Walls Insulated with Straw Bales in a Southern Swedish Climate2016Inngår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    There is a growing need for climate-conscious constructions. Exterior walls insulated with straw bales are potentially a step in this direction. The straw is locally produced, carbon neutral, and has good energy efficiency. However, the susceptibility of straw to mold is a major concern in temperate climates. The purpose of this study was to investigate the risk of mold growth in exterior walls insulated with straw bales. Through computer simulations using the software Wärme Und Feuchte Instationär (WUFI), the relative humidity and temperature in vented and unvented exterior straw bale walls were examined under southern Swedish climactic conditions. The relative humidity and temperature were then applied to three different mold models: the Isopleth, the Folos 2D-, and the Mold Resistance Design (MRD) model. A parametric study was also conducted to ascertain the most sensitive parameters for straw bales. One of the primary objectives was to investigate whether there was any construction that had no risk of mold growth. The study showed that the common design solutions for straw bale constructions were likely to incur a risk of mold growth. Ventilated, infrequently used straw bale constructions incurred less risk of mold growth.

  • 57.
    Rudak, Pavel
    et al.
    Belarusian State Technological University.
    Barcik, Stefan
    Technical University in Zvolen.
    Ekevad, Mats
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknik.
    Rudak, Oksana
    Belarusian State Technological University, Department of Technology and Design of Wooden Articles, Forestry and Wood Technology Faculty.
    Vanco, Marek
    Technology University in Zvolen, Depertment of Environmental and Forestry Machinery, Faculty of Environmental and Manufacturing Technology.
    Stefkova, Jaroslava
    Technology University in Zvolen, Institute of Foreign Languages.
    Motion of chips when leaving the cutting zone during chipboard plane milling2017Inngår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 13, nr 1, s. 646-661Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Mathematical equations were established and the following regularities of the plane milling process of wood materials were analyzed: the effect of the cutting edge inclination angle on the chip exit angle, influence of the cutting edge inclination angle on the speed of chip movement along the blade and exit speed of the chips from the cutting zone, the dependence of the chip exit angle on the friction coefficients of the chips on the processed material surface and along the blade surface (the friction coefficients were determined from the results of the experimental measurements), and influence of the mill rotation frequency on the chip exit angle. The milling of the chipboards with various mill designs was performed at different cutting conditions (diameter = 7 mm to 24 mm, number of cutting elements = 1 to 3, cutting edge inclination angle = -5° to 20°, frequency of the mill rotation = 3000 min-1 to 24000 min-1, feed per tooth = 0.1 mm to 1.5 mm). The process of chip exit from the cutting zone was photographed, and the chip exit angles were measured. A comparison of the values of the chip exit angles obtained from the experiments with those from the calculations based on the developed mathematical equations showed a high convergence.

  • 58.
    Sadatnezhad, Seyed Hamzeh
    et al.
    Gorgan University of Agricultural Scienes & Natural Resources.
    Khazaeian, Abolghasem
    Gorgan University of Agricultural Scienes & Natural Resources.
    Sandberg, Dick
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknik.
    Tabarsa, Taghi
    Gorgan University of Agricultural Scienes & Natural Resources.
    Continuous surface densification of wood: A new concept for large-scale industrial processing2017Inngår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 12, nr 2, s. 3122-3132Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Fast growing and low-density species can be modified by various thermo-hydro-mechanical (THM) treatments. Wood densification is one of the promising techniques for broadening the application of these species. This study focuses on the use of a high-capacity continuous pressing technique that considerably increases the density in the region beneath the surface of poplar wood. Prior to densification at 185 °C, a softening stage was implemented, with water spraying followed by heating at a temperature of 205 °C to 235 °C. The density profile, set-recovery, and morphology of the densified surface were investigated. Densitometry revealed that an M-shaped density profile was created through the thickness, with a peak density of approximately 700 kg/m3 close to the surfaces. The set-recovery after three wetting-drying cycles was 44%, which revealed that partial stress relaxation occurred during the densification. Scanning electron microscopy (SEM) confirmed that both sides of the wood were successfully densified and that after the wetting-drying cycles, the deformed cells did not completely recover.

  • 59.
    Sehlstedt-Persson, Margot
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknologi.
    Karlsson, Olov
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknologi.
    Natural durability and phenolic content in dried Scots Pine heartwood2010Inngår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 5, nr 2, s. 1126-1142Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The durability of Scots pine heartwood has previously been shown to be affected by the industrial drying process of sawn lumber. The durability of heartwood from boards dried at temperatures between 20°C-110°C was studied by measuring the mass loss in a decay test with a brown rot fungus (Coniophora puteana), and the concentration of total phenolics was measured according to the Folin-Ciocalteu (FC) assay. The relation between mass loss and phenolics in dried heartwood showed a weaker negative correlation at lower levels of phenolics as compared to the strong relationship found in a study on heartwood from standing Scots pine trees. Mass loss in dried heartwood showed a weak negative correlation to density. Heating of extractives-rich green sawdust under moist conditions resulted in a reduction of phenolics with temperature up to 180 oC and with increasing time. The concentration of phenolics in heated, green sawdust was higher in extractives-rich pine heartwood than in heartwood with a normal extractives content.

  • 60. Torniainen, Petteri
    et al.
    Elustondo, Diego
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknik.
    Dagbro, Ola
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknik.
    Industrial Validation of the Relationship between Color Parameters in Thermally Modified Spruce and Pine2016Inngår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 11, nr 1, s. 1369-1381Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Thermal modification causes the darkening of wood throughout its cross-section because of chemical changes in the wood. After treatment, naturally light wood species look darker or even tropical, depending predominantly on the treatment temperature and processing time. This study investigates the suitability of using color measurement to determine treatment intensity at the industrial scale. The color was determined using the L*, a*, and b* color space, also referred to as CIELab, and the relationship between lightness (L*) and the color parameters (a*) and (b*) was investigated for thermal modification treatments at 190 and 212 °C. The wood species studied were pine (Pinus sylvestris L.) and spruce (Picea abies L.). The results showed that yellowness (+b*) and redness (+a*) had a significant prediction ability for class treatments at 190 and 212 °C, respectively. After treatment, there were no noticeable differences in color between the species, but sapwood was darker than heartwood in both untreated and thermally modified wood. The thickness of the boards had a proportionally darkening effect on the color values.

  • 61.
    Trischler, Johann
    et al.
    Linnéuniversitetet.
    Sandberg, Dick
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknologi.
    Monocotyledons in particleboard production: adhesives, additives and surface modification of Reed canary grass2014Inngår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 9, nr 3, s. 3919-3938Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 62.
    Trischler, Johann
    et al.
    Linnaeus University, Växjö.
    Sandberg, Dick
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknologi.
    Thörnqvist, Thomas
    Linnaeus University.
    Evaluation the competition of lignocellulosic raw materials for their use in particleboard production, thermal energy recovery, and pulp- and papermaking.2014Inngår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 9, nr 4, s. 6591-6613Artikkel i tidsskrift (Fagfellevurdert)
  • 63.
    Turesson, Jonas
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknik.
    Wang, Xiaodong (Alice)
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknik.
    Gustafsson, Anders
    SP Technical Research Institute of Sweden, SP Sustainable Built Environment, Skellefteå, Sweden.
    Wall Heating: An Energy Efficient Solution for Wooden Buildings?2016Inngår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 11, nr 1, s. 530-544Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Wall heating is an alternative method for residential heating that is used in a limited part of Europe. The goal of this study was to show the feasibility of this method for the Nordic market and to provide a comprehensive picture of wall heating and its functionality compared to traditional methods, i.e. radiators and floor heating. The study was conducted using literature reviews, calculations, and a survey. Simulations were made using the computer software EnergyPlus (US Department of Energy). Results showed that placement of wall heating panels in interior walls results in a lower heat loss than placement in outer walls, and that wall heating can have equal or better energy-efficiency compared to floor heating and conventional radiators. Wall heating provides a more comfortable indoor climate, in regard to dust allergies, and there is no need to remove air from each individual heating panel. A disadvantage is the need for hidden installation, which creates a problem for a safe water installation and difficulties in the attachment of fixtures. Also, the wall heating system has difficultly in handling cold drafts. Though wall heating could compete with floor heating and radiators, its disadvantages are sufficient to explain why the system is not yet used in Sweden.

  • 64.
    Wang, Alice
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknik.
    Björnberg, Jonatan
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknik.
    Hagman, Olle
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknik.
    Ahmed, Sheikh Ali
    Department of Forest Products, Linnaeus University, Växjö, Sweden.
    Wan, Hui
    Mississippi State University, Department of Sustainable Bioproducts, Mississippi , Forest Products Laboratory, Mississippi State University, Mississippi State, Department of Sustainable Bioproducts, Mississippi State University, Mississippi State.
    Niemz, Peter
    Department of Civil Engineering, ETH Zurich, Switzerland.
    Effect of Low Temperatures on the Block Shear Strength of Norway Spruce Glulam Joints2016Inngår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 11, nr 4, s. 9638-9648Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The block shear strength of Norway spruce (Picea abies (L.) Karst.) glulam joints was tested under low temperatures. Glulam samples were glued with the three of the most common outdoor structural adhesives. The cold temperatures tested were 20, -20, -30, -40, -50, and -60 degrees C. Within the temperature test range, the block shear strength of the glulam joints was resistant to the effect of temperature. As the temperature decreased, the joints' block shear strength did not show any significant change. In most cases, phenol-resorcinol-formaldehyde (PRF) adhesive yielded the strongest block shear strength, while melamine-formaldehyde (MF) adhesive yielded the weakest block shear strength. Melamine-urea-formaldehyde (MUF) adhesive yielded similar results to those of MF adhesives for all temperatures tested. The block shear strengths of the glulam joints with PRF, MUF, and MF adhesives were not sensitive to temperature change. The results indicated that PRF, MUF, and MF adhesives are stable for outdoor structural engineered wood construction in cold climates. The results also suggest that the SS-EN 14080 (2013) standard for the block shear method may not be the proper standard for testing differences in shear strength at different temperatures. The EN 302-1 (2011) standard could be more suitable for this purpose.

  • 65.
    Wang, Xiaodong (Alice)
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknik.
    Hagman, Olle
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknik.
    Sundqvist, Bror
    SP Technical Research Institute of Sweden, SP Sustainable Built Environment, Skellefteå, Sweden.
    Ormarsson, Sigurdur
    Department of Civil Engineering, Technical University of Denmark, Denmark.
    Wan, Hui
    Department of Sustainable Bioproducts, Mississippi State University, Mississippi State.
    Niemz, Peter
    Department of Civil Engineering, ETH Zurich, Switzerland.
    Shear strength of Scots pine wood and glued joints in cold climate2016Inngår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 11, nr 1, s. 944-956Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The impacts of cold temperatures on the shear strength of Scots pine (Pinus sylvestris) joints (150 mm x 20 mm x 10 mm) glued with seven commercially available adhesives were studied in this work. The adhesives used here were: polyurethane (PUR), polyvinyl acetate (PVAc), emulsion-polymer-isocyanate (EPI), melamine-formaldehyde (MF), phenol-resorcinol-formaldehyde (PRF), melamine-urea-formaldehyde1 (MUF1), and melamine-urea-formaldehyde2 (MUF2). The cold temperatures investigated here were: 20, -20, -30, -40 and -50 °C. Generally, within the temperature test range, the shear strength of Scots pine solid wood and wood joints resisted more temperature effects than Norway spruce. As the temperature decreased, only some of the joints shear strength decreased significant. PUR adhesive in most cases resulted in the strongest shear strength and MUF adhesive resulted in the weakest. MF adhesive responded to temperature changes in a similar manner to that of the PUR and PVAc adhesives. The shear strengths of wood joints with PRF and EPI adhesives were more sensitive to temperature change. For dynamic tests of shear strength, the values for 12 hours and 6 days tests under cycled of temperature (-20°C and 0°C) were compared. For 6 days tests, the values for the various types of the adhesives are lower than for 12 hours. Therefore, the duration of the samples subjected to the same temperature had significant impact on shear strength. PUR is the most stable adhesive; MUF and PRF have significant decrease.

  • 66.
    Wei, Wei
    et al.
    Fujian Agriculture and Forestry University, Fuzhou, China.
    Chen, Tingjie
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknik. Fujian Agriculture and Forestry University, Fuzhou, China.
    Miu, Min
    Fujian Agriculture and Forestry University, Fuzhou, China.
    Xie, Yongqun
    Fujian Agriculture and Forestry University, Fuzhou, China.
    Wang, Alice
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknik.
    Optimized Pretreatment of Kenaf (Hibiscus cannabinus) Phloem Insulation Cotton2016Inngår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 11, nr 1, s. 2583-2596Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Using response surface methodology, the pretreatment conditions of kenaf fibers were optimized to improve the tensile strength of kenaf phloem insulation cotton (KPIC). The effects and interactions of three parameters—sodium hydrate concentration (X1), soaking time (X2), and beating time (X3)—on the tensile strength of the kenaf fibers were investigated. The chemical structure of the specimens was characterized by Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). Sodium hydrate concentration had the greatest effect on kenaf fibers. The maximum tensile strength of 117.6 N resulted from a sodium hydrate concentration of 4%, soaking time of 50 h, and beating time of 12 min. As shown by FTIR and XRD, optimized pretreatment generated surface functional groups and increased the tensile strength of fibers. In conclusion, the pretreatment of kenaf fiber significantly improves the tensile strength of KPIC and also improves the retention rate of the chemicals used during the preparation of KPIC.

  • 67.
    Wu, Zhenzeng
    et al.
    Department of Material Engineering , Fujian Agriculture and Forestry University, 350002, Fuzhou, Fujian.
    Chen, Tingjie
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknik.
    Huang, Daobang
    D epartment of Material Engineering , Fujian Agriculture and Forestry University, 350002, Fuzhou, Fujian.
    Wang, Wei
    D epartment of Material Engineering , Fujian Agriculture and Forestry University, 350002, Fuzhou, Fujian.
    Xie, Yongqun
    D epartment of Material Engineering , Fujian Agriculture and Forestry University, 350002, Fuzhou, Fujian.
    Wan, Hui
    Department of Forest Products, Mississippi State University, P. O. Box 9800, Starkville, MS 39759 - 9820 USA.
    Wang, Xiaodong (Alice)
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknik.
    Effect of PVDC on the Fire Performance of Ultra-Low Density Fiberboards (ULDFs)2016Inngår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 11, nr 4, s. 8653-8663Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Poly vinylidene chloride-vinyl chloride emulsions (PVDC) were added as a substitute for chlorinated paraffin (CP) in the preparation of ultra-low density fiberboards (ULDFs). The micromorphology and fire performance of ULDFs were investigated using a scanning electron microscope, limiting oxygen index instrument, and cone calorimeter. The results showed that PVDC specimens were coated with a regularly smooth film, while the distribution of CP inside CP specimens was uneven. The limiting oxygen index increased with the dosage of PVDC, then reached a plateau at 50 mL and 28%, slightly higher than CP specimens (27.3%). The peak of heat release rate, mean heat release rate, mean CO, and total smoke release of PVDC specimens was reduced 43.3%, 13.5%, 38.5%, and 51.5% lower than respective CP specimens, and with nearly the same total heat release (only 0.04 MJ/m2 higher). Thus, PVDC exhibited excellent heat-reducing and smoke-suppressing properties and could replace CP in ULDFs. 

  • 68.
    Wu, Zhenzeng
    et al.
    Fujian Agriculture and Forestry University, Fuzhou, China.
    Chen, Tingjie
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknik.
    Niu, Min
    Fujian Agriculture and Forestry University, Fuzhou, China.
    Cai, Lili
    Fujian Agriculture and Forestry University, Fuzhou, China.
    Xie, Yongqun
    Fujian Agriculture and Forestry University, Fuzhou, China.
    Wang, Alice
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknik.
    Effect of Boron-Zinc-Aluminum-Silicium Compounds on the Fire Performance of Ultra-Low Density Fiberboards2016Inngår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 11, nr 2, s. 5050-5063Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    B-Zn-Si-Al compounds are modified Si-Al compounds made of sodium silicate, zinc sulfate, borax, and aluminum sulfate. They act as a fire retardant during the preparation of ultra-low density fiberboards (ULDFs). An orthogonal experiment was used to optimize the contents of the four compounds according to the limiting oxygen index. Fourier transform infrared spectroscopy was employed to preliminarily analyze the chemical structure of the compounds. Additionally, a cone calorimeter was used to assess the fire performance of the ULDFs. The results suggested that the optimized solution was made of 27.0 mL of sodium silicate solution, 27.0 mL of aluminum sulfate solution, 3.0 g of zinc sulfate, and 6.5 g of borax, resulting in an oxygen index of 29.5%. The bond Al-O-B was detected at 1397 and 796 cm-1. The Si-O-Zn bonds were detected at 867 cm-1. The heat release rate, total heat release, and total smoke release decreased and the mass residual ratio increased in the sample using the optimal conditions from the orthogonal array design. It was concluded that B-Zn- Si-Al compounds effectively protect fibers from fire.

  • 69.
    Wu, Zhenzeng
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknik.
    Huang, Daobang
    Department of Material Science and Engineering, Fujian Agriculture and Forestry University, Fuzhou.
    Wang, Wei
    Department of Material Science and Engineering, Fujian Agriculture and Forestry University, Fuzhou.
    Chen, Tingjie
    Department of Material Engineering, Fujian Agriculture and Forestry University, Fuzhou, Fujian.
    Lin, Ming
    College of Material Engineering, Fujian Agriculture and Forestry University.
    Xie, Yongqun
    College of Material Engineering, Fujian Agricultural and Forestry Universit.
    Niu, Min
    Department of Material Engineering, Fujian Agriculture and Forestry University, Fuzhou, Fujian.
    Wang, Alice
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknik.
    Optimization for fire performance of ultra-low density fiberboards using response surface methodology2017Inngår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 12, nr 2, s. 3790-3800Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The optimization of the process conditions for fire retardant ultra-low density fiberboards (ULDFs) was investigated using response surface methodology (RSM). Three parameters, namely those of Borax-Zinc-Silicate-Aluminum (B-Zn-Si-Al), chlorinated paraffin (CP), and chloride-vinyl chloride emulsions (PVDC) were chosen as variables. The considerably high R2 value (99.98%) indicated the statistical significance of the model. The optimal process conditions for the limiting oxygen index (LOI) were determined by analyzing the response surface's three-dimensional surface plot and contour plot, and by solving the regression model equation with Design Expert software. The Box-Behnken design (BBD) was used to optimize the process conditions, which showed that the most favorable dosages of B-Zn-Si-Al, CP, and PVDC were 800 mL, 46.47 mL, and 35.64 g, respectively. Under the optimized conditions, the maximum LOI was 48.4.

  • 70.
    Xie, Lan
    et al.
    Department of Civil Engineering and Mechanics, Central South University of Forestry and Technology.
    He, Guojing
    Department of Civil Engineering and Mechanics, Central South University of Forestry and Technology.
    Wang, Alice
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknik.
    Gustafsson, Per Johan
    Division of Structural Mechanics, Department of Building Sciences, Lund University.
    Crocetti, Roberto
    Division of Structural Mechanics, Lund University.
    Chen, Liping
    Hunan Huagang Planning and Design Research Institute Co.
    Li, Li
    Department of Civil Engineering and Mechanics, Central South University of Forestry and Technology.
    Xie, Wenhui
    Department of Civil Engineering and Mechanics, Central South University of Forestry and Technology.
    Shear Capacity of Stud-Groove Connector in Glulamconcrete Composite Structure2017Inngår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 12, nr 3, s. 4690-4706Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    timber-concrete composite structure (TCC) is economically and environmentally friendly. One of the key design points of this kind of structure is to ensure the reliability of the shear connectors. The objective of this paper is to study the mechanical property of stud-groove-type connectors and to provide shear capacity equations for stud-groove connectors in timber-concrete composite structures. Based on the Johansen Yield Theory (European Yield Model), some mechanical models and capacity equations for stud-groove-type connectors in timber-concrete structures were studied. Push-out specimens with different parameters (stud diameter, stud length, groove width, and groove depth) were tested to obtain the shear capacity and slip modulus. The experimental strengths were used to validate equations given in the paper. The shear capacity and slip modulus of stud-groove-type connectors was in direct proportion to the diameter of studs and the dimension of the groove. Comparison between the theoretical and the experimental shear strength results showed reasonable agreement. The highlight of this study on shear capacity equations could significantly reduce the push-out tests before investigating the other properties of TCC

  • 71. Yang, Qian
    et al.
    Karlsson, Olov
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknologi.
    Ahmed, Sheikh Ali
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknologi.
    Morén, Tom
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknologi.
    Dimensional stability and water repellency of european aspen improved by oxidized carbohydrates2013Inngår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 8, nr 1, s. 487-498Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Small samples from European aspen (Populus tremula L.) were impregnated with carbohydrates oxidized by Fenton’s reagent using water in a vacuum, followed by heating in an oven at 103°C. An antiswelling efficiency (ASE) of around 45% for wood treated with oxidized glucose and 35% for wood treated with oxidized sucrose was obtained. Samples treated with oxidized carbohydrates gave water repellent effectiveness (WRE) values over 35%. The decrease in cell wall thickness during impregnation was about 18% less in the presence of oxidized glucose than samples only treated with Fenton’s reagent. An ASE of 20% for the wood samples that had been treated with oxidized glucose was obtained after 7 days of soaking in water. The reasons for the improvement in dimensional stability are discussed in this work.

  • 72.
    Yoon, Kukjin
    et al.
    Graduate School of Life and Environmental Sciences, University of Tsukuba.
    Takahashi, Shiho
    Forestry and Forest Products Research Institute, Tsukuba, Ibaraki.
    Nge, Thi Thi
    Graduate School of Life and Environmental Sciences, University of Tsukuba.
    Karlsson, Olov
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Träteknologi. Forestry and Forest Products Laboratory, Tsukuba, Ibaraki.
    Nakagawa-izumi, Akiko
    Graduate School of Life and Environmental Sciences, University of Tsukuba.
    Ohi, Hiroshi
    Graduate School of Life and Environmental Sciences, University of Tsukuba.
    Uraki, Yasumitsu
    Faculty of Agriculture, Hokkaido University, Sapporo.
    Yamada, Tatsuhiko
    Graduate School of Life and Environmental Sciences, University of Tsukuba, Forestry and Forest Products Research Institute, Tsukuba, Ibaraki.
    Thermal Melting of Lignin Derivates Prepared from Dried Black Liquor Powder of Softwood Soda-AQ Cooking and Polyehylene Glycol2015Inngår i: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 10, nr 1, s. 912-921Artikkel i tidsskrift (Fagfellevurdert)
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