Showing papers in "China Wood Industry in 2007"

The Development of Straw-based Composites Industry in China

Abstract: The development of straw-based composites industry in China would help solve the shortage of timber supply and contribute to the protection of forest resources and the environment. Thes first presented the current status of agri-residue straw resource utilization both in China and abroad;then listed the primary products manufactured with straw-based panels,analysed the characteristics of the manufacturing technology of these panels as well the panel application in different fields.Finally,some suggestions were made for further development for the straw-based composites industry in China.

Progress on the Testing Methods for Mechanical Properties of Dimensional Lumber

Abstract: Dimensional lumber is an important building material in modern lightweight timber frame structure.As a newly introduced building material,research on its properties remain at a preliminary stage in China.The authors first describe the concept of dimensional lumber and the progress of in-grade testing for dimensional lumber in North America.They then analyze the effects of different testing conditions for mechanical properties and predict the trend of testing methods for mechanical properties of dimensional lumber.Finally,the authors make some suggestions for further research for testing methods.

Surface Roughness and Sanding Quality Control for Wood Furniture

Abstract: The author first analyzed some problems in the engineering practice of sanding work according to the national standards.Currently,many workers in furniture factories actually judge the quality of sanding work by relying on their experience.The author made suggestions on how to improve the efficiency and quality of sanding work.

Aldehyde and Terpene Emissions from Four Species of Wood at Normal Temperature

Abstract: Pure helium gas was applied to wood particles which were placed in a vessel.Aldehyde was collected by a 2.4-DNPH cartridge and analyzed by HPLC.Terpene was collected by an active carbon tube and analyzed by GC-FID.The results showed that aldehydes,such as formaldehyde,acetaldehyde,hexaldehyde,etc,and terpenes,including α-pinene,β-pinene and D-limonene,were released from green wood particles of Chinese Fir,Poplar,Masson's Pine and Eucalyptus urophylla at 40℃.Acetaldehyde emission was much more than other components.Aldehyde emissions from Chinese Fir and Poplar were higher than from Masson's Pine and E.urophylla.Terpene emission from Chinese Fir was much more than from the other 3 species of wood.When the temperature rose from 20℃ to 40℃,the volume of aldehyde and terpine emissions from Chinese Fir increased considerably.

Study on the Effectiveness of Plywood as an Electromagnetic-shield

Abstract: Some electric materials,such as Ni powder,graphite powder,stainless steel fiber and copper fiber,were added to urea-formaldehyde resin to manufacture plywood that would act as an electromagnetic shield.The influence of different electro-conductive elements and adhesive spread on shielding and bonding strength of Larix plywood was investigated.The results showed that shielding from plywood with the addition of pure Ni powder was nearly zero and that the addition of graphite powder,stainless steel fiber and copper fiber were 5~10 dB,17~21 dB and 6~17 dB respectively.Except the bonding strength was 0.46 MPa,which was lower than the national standard when the spread of stainless steel fiber was 80 g/m2,under other conditions,the bonding strength of the plywood could meet or exceed the requirements of the related national standard.

Detection of Decay and Insect Attacked Ancient Wood Members with Stress Wave Methods

Abstract: Decayed and insect attacked ancient poplar and larch wood components from the buildings of Tibet were inspected by a stress wave meter(FAKOPP).The decay in each wood component was observed and classified after having been measured by FAKOPP.The comparison between the stress wave evaluation and visual classification showed that internal wood decay and insect infestation on ancient wood components could be detected accurately by stress wave.The decay situation evaluated by stress wave was almost consistent with the visual classification.Based on the results,the authors determined that visual observation combined with stress wave methods could examine the degradation of wood members in ancient buildings.

Present Status of Fireproofing for Wooden Buildings

Abstract: With greater economic development and the improvement of people's standard of living,modern wooden structures have become a new hot spot in current construction.Therefore,fireproof performance of wooden buildings is becoming more and more important.The authors first introduce the development status of wooden buildings in China.They then describe the advantages of fireproofing wooden buildings as compared to steel construction and reinforced concrete construction.In conclusion,they make some suggestions for further research and development trends on fireproofing of wooden buildings.

Analysis on Feasibility of Industrialization for Reconstituted Bamboo Timber

Abstract: This paper summarized research progress in reconstituted bamboo timber,and discussed the feasibility of its industrialization from four aspects:resource,technology,marketing and investment benefitsIt was proposed that developing reconstituted timber could change the current status of basically depending on large-size Moso bamboo and low utilization rate for bamboo resourcesIncreasing the use of small diameter bamboo and bamboo residues would help save precious bamboo resources and improve economic benefits

Technology and Application on Heat-treated Solid Wood Flooring

Abstract: White ash(Fraxinus chinensis),Mongolian oak(Quercus mongolica),Camphor wood(Cinnamomum camphora),Chinese gugertree(Schima superba) blanks of solid-wood flooring were heat-treated with super-high temperature.The technology was applied in a wood factory in Nanxun,Zhejiang Province based on laboratory experiments.Compared with the common solid wood flooring,moisture adsorption of heat-treated wood decreased by 51.87% and dimensional stability increased by 42.36%.Also,tangential modulus of elasticity and longitudinal compression strength increased by 1.15% and 2.19% respectively,but tangential bending strength reduced substantially.Heat-conduction ability was better than untreated solid-wood flooring used as ground heating flooring.

Effect of Alternate Adsorption-Desorption Treatments on Shrinkage and Bulking Properties of Eucalyptus urophylla×grandis

Abstract: Alternate adsorption-desorption treatments were carried out on Eucalyptus urophylla ×grandis wood through cyclic humidity exposure and recording the real-time tangential shrinkage and bulking properties.The results showed that the initial moisture content had a notable effect on the tangential shrinkage of Eucalyptus urophylla×grandis,while the times of alternate adsorption-desorption treatments only affected the tangential bulking property.The cyclic humidity treatments also shortened the shrinkage and bulking vibration periods,and thus was helpful in alleviating deformation and keeping dimensional stabilization.

A Study on the Surface Hardening of Soft Wood

Abstract: Experiments for surface hardening of soft wood were described.The effects of compression of soft wood impregnated with phenol-formaldehyde resin were studied.The results showed that the density of the treated wood samples varied in a gradient from the outer shell to the inner core.The density of the surface was higher than that of the core and the average density.The hardness and abrasive property of the surface,and the anti-shrink efficiency of the treated wood samples,were all improved.

Design of the Veneer Automatic Classification System Based on Computer Vision

Abstract: This paper discusses the research and development of wood and veneer automatic classification technology,and proposes a design method for the classification system based on computer vision.

Research on the Gluability of Four Plantation Grown Eucalyptus Species

Abstract: This paper analyzed and tested the gluability of glued laminated lumber by four plantation grown Eucalyptus species focusing on gluing pressure and adhesive consumption. The results showed that two high density species of Eucalyptus (E.citriodora and E.exserta) have poor bonding performance with lower wood failure.The other two Eucalyptus species (E.grandis and E.urophylla×E.grandis) with lower density showed better performance.

Research Status and Developing Trends of Finger-jointed Lumber

Abstract: This paper first reviews the research that has been done on finger-jointed lumber.It then analyzes the main problems that exist in the finger joint industry,such as low strength,poor quality,poor fit and surface roughness,etc.Finally,it presents some suggestions for future research on finger joints from finger cutter,adhesive and property evaluation methods.

Review of Research on Electromagnetic Shielding Wood Composites

Abstract: This paper summarizes the research on electromagnetic shielding for wood composites both in China and abroad.It also analyzes the future development and potential applications of electromagnetic shielding of wood composites.

Log Storage from Ancient Architectural Structures in Need of Repair or Replacement

Abstract: The repair and replacement of the wood components in ancient buildings is one of the main aims of ancient architectural repair.The problem of wood material storage,for wood that is in need of repair,is an urgent one requiring a solution This paper discusses the problem,and solution,of choosing wood material and the storage of logs from ancient wooden structures that need repair.As the zone of concern expands and complex climate conditions are encountered,more species are found that are at great risk.The protective treatment processes for log storage will change with the change in conditions.

An Accelerated Laboratory Test Method to Assess Wood Decay

Abstract: A carton with a polyethylene bag lining was used as a culture vessel for sweet gum veneer feeder strips.Soil,water,feeder strips,and specimens were sterilized and added to the culture bag for a decay test.Variance of analysis results by Statistical Analysis System(SAS)showed that the effect of fungi species and exposure periods on the weight loss and strength loss of wood decay was significant(at 0.05 level),and the relationship between weight loss and strength loss due to biological decay were also very significant.The results suggested that the experimental method designed by the authors was a feasible way to assess wood decay.

A Study on the Color Fastness of Dyed Veneer to Water

Abstract: Veneer,dyed by acid dyes,easily fades because of its poor color fastness to water.In order to improve the color fastness to water,the veneers(Betula spp.)were treated with different color fastening agents after dyeing,and the influences of the different agents to the dyed veneer were investigated in this paper.The results proved that the veneer dyed with the color fastening agent of KAl(SO4)2,compared with other five mineral salts such as Na2SO4,CuSO4,etc.,had advantages of small color variation and excellent color fastness.The veneer treated by fastening agent Y could also gain a good effectiveness but was not environmentally-friendly.The effectiveness of veneer coated by chitosan after dyeing was the best among those treated with KAl(SO4)2 and fastening agent Y,respectively,that not only had small color variation but considerably improved the stability of dyeing.

Plant-based Phenolic Compounds as Raw Materials for Replacing Petroleum Phenol in the Formulation of Resol

Abstract: The utilization of plant-based phenolic compounds enlarges the sources of raw materials, reduces cost,and promotes implementation of sustainable development.This paper reviews the research on adhesives derived from lignin,tannin,wood liquefaction,and oil pyrolysis.In order to obtain wider application of these adhesives,it also indicates that it should be necessary to further explore the mechanism of these adhesives,strengthen the modification studies,further lessen the cost,and continue to expand the sources of new raw materials.

Effect of the Amount of Resin Impregnation on the Properties of Poplar LVL

Abstract: Laminated veneer lumber(LVL) was manufactured from poplar veneer,that had been impregnated with low-molecular-weight water-soluble phenol-formaldehyde resin.The effects on the mechanical and physical properties of the LVL were investigated when made from veneer that had been subjected to various levels of the resin treatment.The results indicated that either at normal temperature and pressure,or under an increased pressure condition,the resin impregnation in veneer increased as the impregnating time was prolonged.When the resin impregnation increased,LVL physical and mechanical properties improved significantly.When the resin impregnation was 168%,the modulus of elasticity(MOE)and modulus of rupture(MOR) of the LVL reached 140E and 180E grade of JAS SIS-24 《Structural Laminated Veneer Lumber》 standard,respectively.

The Effects of Wood/Jute/Polypropylene Fiber Contents on the Properties of the Composite

Abstract: The effects of the different fiber contents on the properties of the Wood fiber/jute fiber/polypropylene fiber composite are discussed in this paper.The composites are formed with nonwoven air formed method in mats and are pressed in panels.The results indicate that the MOR and water resistance properties of the composites were improved by adding much more PP fibers.Increasing jute fiber can improve the MOR and MOE of the composites obviously,but the water resistance properties are decreased at the same time.The composite will get the best properties while it consists of 40% PP fiber,30% jute fiber and 30% wood fiber.

Withdrawal Strength of Wooden Rectangular Mortise-tenon Joint without Bond

Abstract: Rectangular mortise and tenon joints are widely used in the furniture industry and wood timber engineeringIn this study,the effects of tolerance,embedded length,and grain direction on the pull-out resistance of the rectangular mortise and tenon joint were investigatedThe main findings were summarized as follows:1) The pull-out load vspull-out displacement curve of the rectangular mortise and tenon joint consisted of a linearly ascending part and a descending part2) The pull-out load was improved by tightening the assembling tolerance within the range without the mortise and tenon joint causing damage during assembly3) The pull-out load increased with the increase of the embedded lengthHowever,the maximum pull-out load was found to be at 35 mm embedment length4) The pull-out load along the grain direction was greater than that across the grain direction under the same conditions

Wood Preservation Plants in China:Problems and Suggestions

Abstract: The authors analyzed the problems existing in some wood preservation plants in China such as plant design,equipment installation,product quality control,production process,safety production and environmental protection.Some suggestions were then made for solving the problems that had been identified.

A Study on Manufacturing Technology for Bamboo OSB with PF Resin

Abstract: Bamboo Oriented Strand Board(BOSB),a multi-layer structural board,is made from bamboo strands by oriented forming and hot pressing.The technology for BOSB manufacturing was studied and the technological parameters,such as bamboo strand dimensions,PF resin consumption, and hot pressing conditions,were determined.The testing results showed that the properties of BOSB could meet the requirements of the Forestry Industrial Standard LY/T 1580-2000 for OSB/3 in grade one.

Effect of Different Heating Methods on Wood Drying Characteristics

Abstract: A series of drying experiments was conducted on plantation grown Poplar(Populus deltoids cvI-69-55)and Masson’s pine(Pinus massoniana)lumber by three different heating methods,namely,convection,infrared and microwaveThis paper determined the drying rate and energy consumption for those three drying methods,and also analyzed how the wood drying characteristics were influenced by the heating methods,wood species and lumber thicknessResults found that:1) The heating method affected the drying rate significantlyOne-way hyperbola model indicated that the relationship between heating method and drying rate was close for the convection and infrared method,but not clear for the microwave method;2) The average energy consumption ratio of the 3 heating ways of convection,infrared and microwave,was 1∶101∶064;3) As for the drying quality,convection drying had a long cycle which easily developed defects such as surface or internal cracks in the wood;microwave drying had a more rapid rate,but was likely to result in internal cracks or carbonization,so it was suitable for slabs;infrared drying was inferior in quality,and was only suitable for thin panels

Study on VOC Emissions from Plywood Using a Climate Chamber

Abstract: A climate chamber was used to study the emission of formaldehyde from plywood.Results showed that under certain conditions,the concentration of formaldehyde emitted quickly increased to a maximum value in several hours,and then began to decline until it reached a steady value.In the steady emission state,environmental factors had remarkable effects on formaldehyde and other VOC emissions.A test on the composition of the emissions found the presence of eight different VOCs.