Showing papers in "China Wood Industry in 2010"

Relationship between Modulus of Rupture and Ultimate Tension Strength of Dimensional Larch Lumber

Abstract: The modulus of rupture(MOR) and ultimate tensile strength(UTS) of dimensional larch(Larix gmelinii) lumber were tested according to ASTM D 4761-1996.The probability density function was used to describe MOR and UTS data.The results indicated that logarithmic distribution had the best goodness of fit with MOR and Weibull distribution had the best goodness of fit with UTS.The relationship between MOR and UTS was established as a power function from the cumulative distributions of MOR and UTS.

Current Status and Future Challenges of Wood-based Panel Industry in China

Abstract: After the impact of world financial crises the economy in China is on the way of V shaped recovery. With increasing of economic growth rate,business confidence,domestic demand and export,the demand for wood based panel and other wood related products is steadily growing. This demonstrates the huge potential of the investment market. Large amount of Private Equity capital has started a new round of investment into the wood-based panel industry and speeded up the industry and market consolidation. The study discusses how the wood product industry to face the challenges to the changing economic environments.

The Present Status of Lumber Energy-Saving Drying Technology

Abstract: The authors reviewed the present research status on lumber energy-saving drying technology,and summarized the recent research achievements of wood energy-saving dryingThey considered that solar drying technology was suitable for pre-drying,and that phase change thermal storage was an effective way to solve the intermittent solar drying problemA Solar-heat pump and a solar-conventional combination were ideal drying processesA dehumidifier was commonly used in heat recycling and it was found that it could save up to 40%drying energyThe oscillating-flow heat pipe applied in heat recycling was cost effective equipment and could save 20%～50% drying energy

Predicting Bending Performance of Larch Dimensional Lumber by an Ultrasonic Technique

Abstract: The ultrasonic method,one of the important non-destructive evaluation(NDE) technologies,was used to determine the dynamic modulus of elasticity(DMOE) of dimensional lumber collected from a commercial larch(Larix gmelinii) forestry plantation in China.The modulus of elasticity(MOE) and modulus of rupture(MOR) were measured by a three-point bending test.The relationship between DMOE and static MOE,as well as the one between DMOE and static MOR were analyzed.The results indicated that the average DMOE value was greater than the average MOE value.Moreover,the relationship between DMOE and MOE and the relationship between DMOE and MOR were both significant at the 0.01 level.On the other hand,the determination coefficient between DMOE and MOE was greater than that between DMOE and MOR.

Utilization of Wheat Straw as a Building Material——Oriented Structural Straw Board in a Housing System

Abstract: Considerable straw-based composite research has been done due to the shortage of wood resources and environmental impact from burning straw.To date,various efforts have involved making straw panels with a mixed degree of success.The Forest Products business unit of Alberta Research Council has developed oriented structural straw board(OSSB) in cooperation with Panel Board Holding BV of The Netherlands(PBH).PBH has built up the world's first OSSB factory in China – Yangling board manufacturing of the Leenderson Panel Company.The OSSB product is comparable to wood-based oriented strand board(OSB) in both physical and mechanical properties at comparable densities.For their OSSB application,PBH has also developed a light steel-framed OSSB housing system.This paper will outline the OSSB's manufacturing technique,panel properties,and its housing system.

Processing and Application Technology Development for Larch Dimensional Lumber

Abstract: Larch is one of the most important commercial forestry species in China.Research development,processing and application technology for larch dimension lumber was introduced in this paper.Sponsored by the China National Program for Applied Research,this study focused on lumber sawing,drying,grading,non-destructive testing,static testing of mechanical performance and connection.This work initiated construction of the key and common technological platform for processing dimensional lumbers from domestic resources.

Current Status,Development and Prospect of Wood Identification Technology

Abstract: The current status of wood identification technology,which primarily includes macro-and macro-/micro-identification techniques,was reviewed in this paper.The description of the glossary,the definitions of wood features,and the assistant tools and the basis of wood nomenclature were explained.Three new technologies,DNA markers,stable isotope,and near-infrared spectroscopy(NIR),were described.The authors believe that the new technologies could be used to identify the botanical species and trace the location from where the wood originated.However,further research and development should be enhanced for their commercialization in the wood identification field.

Mold and Decay Resistance of Reconstituted Bamboo Lumber

Abstract: Reconstituted bamboo lumber(RBL) made with phenol-formaldehyde resin(PF),thermo-treated RBL also made with PF,and a commercial RBL product were compared and evaluated for mold and decay resistance performanceThe results showed that all RBL samples had good decay resistance and met the grade requirementHowever,all products had a little effect on mould growth and none were able to prevent blue stain fungus

Energy Consumption Analysis for High-Temperature and Dehumidification Drying

Abstract: Populus deltoides lumber were dried using high temperature dehumidification and conventional methods under the same schedule.Energy consumption and drying quality during the two drying methods were monitored and compared.Results showed that the energy consumption was different during various drying stages.It was found that the most effective way to save energy was in the initial period and it could save up to 30.5%.The high-temperature dehumidification drying consumed 34.1% less energy than the conventional drying without compromising the drying quality.It was expected that high-temperature dehumidification would increase its popularity along with the conventional drying in the future.

Effects of Major Defects on Dimensional Larch Lumber Visual Grading

Abstract: Three groups of Dahurian larch(Larix gmelinii) dimension lumber with different dimensions of 40 mm × 65 mm × 4000 mm,40 mm × 90 mm× 4000 mm,and 40 mm × 140 mm× 4000 mm,were visually graded according to Chinese Standard GB 50005-2003.The main defect causes that degraded the lumber were identified for each group.The results showed that:1) different sizes of lumber differentiated in proportion to each grade of dimension lumber;2) knots,shake/checks and skips were the main defects that lowered the lumber grade.It was proposed that further study should be conducted toward optimizing processing and drying methods to improve the quality of dimension lumber.

Process of Chemical Modification and Multilayer-Press Drying of Radiata Pine

Abstract: The authors impregnated radiata pine(Pinus radiata,from New Zealand)logs with a modified urea solution to improve lumber performance,sawed the logs into dimensional lumber after chemical treatment,and then densified the lumber with a multilayer press at 90 ℃ in a drying kilnThe densified lumber bending strength,modulus of elasticity,compressive strength parallel to wood grain,and drying qualities were improved considerably and met the specification of the Chinese national standard GB/T 6491-1999 for second grade lumber

Nailed Joint Performance of Larch Dimensional Lumber

Abstract: The nail joint is a common connection used in timber structures.This paper focuses on nailed joint performance of larch lumber,a common species in northeast China.The authors introduced the test methods for American nailed joints and how to develop the design values for wood structures with domestic wood species. The results could be used to develop design values of larch in this area.

Research and Development of Bamboo Fiber for Textile Applications in China

Abstract: The authors summarized the classification and basic properties of bamboo fiber used in textile applications.They then reviewed how the status and standards related to this material and applications.Finally,they analyzed the problems in the development and utilization of bamboo fibers,and trends for further research and development.

Surface Roughness of Wood Cut by Extra-High Pressure Water-Jet

Abstract: High pressure water-jet cutting technique is increasingly visible in furniture and floor manufacturing process in ChinaIn order to evaluate the surface quality and efficiency of extra-high pressure water-jet cutting,an orthogonal experiment was designed for three wood species to determine the effect of wood density,water pressure,feed-in speed,sand particle size,and cutting thickness on the surface qualityThe test result would provide a useful reference to improve rare tropical wood flooring production

Value Engineering Analysis on Soundproof Flooring

Abstract: A soundproof flooring,made with a wood-rubber composite,is a new flooring product for the Chinese market.The authors used a value engineering system to evaluate the flooring cost and function.First,they analyzed the function of each flooring component and estimated the cost coefficients on a 0～1 evaluation method.Then,they adopted the most appropriate method to conduct the evaluation.The results showed that the structure and material consumption of the soundproof flooring was optimized.

Mold Inhibition of Heat-Treated Lumber

Abstract: This study was performed to evaluate the mildew resistance of heat-treated lumber Dinitrosalicylic acid was used to estimate the sugar content in heat-treated birch and Mongolian pine samples The results showed that heat-treated lumber was more susceptible to mold growth than their untreated control samples Furthermore,the outside layers of the heat-treated samples were more prone to mold growth than the inside layers No mold growth was observed on the surfaces coated with varnish The sugar content of heat-treated samples increased with higher treatment temperature and the sugar content of the outside layers was usually higher than the core

Density Distribution of Reconstituted Birch Lumber with Different Hot Pressing Processes

Abstract: Birch veneers impregnated with melamine-formaldehyde resin (MF) were used to make reconstituted lumber. Two hot pressing methods,high-frequency and traditional hot-platen,were used and their influences on the density distribution of reconstituted birch lumber was analyzed. The results showed different heat transfer due to the different hot pressing methods and had considerable impact on the density distribution in the length,width and the thickness directions. Thus,when producing reconstituted lumber with thickness above 30 mm,we recommend using a high frequency hot-pressing method to maintain a uniform density distribution.

Forming and Influencing Factors of Veneer Back Clearance during Longitudinal Slicing

Abstract: A typical process for slicing oak veneer was recorded using a camera with a magnifier.The development and formation of back clearance were described,and observed and analyzed during slicing.We found that cutting thickness,inclination angle,and cutting speed were the major factors influencing veneer back clearance during slicing.

Effect of Superheated Steam Pretreatment on Drying Quality of Larch Square during Radio Frequency/Vacuum Drying

Abstract: Different temperatures of superheated steam were used to pre-treat boxed-heart larch lumber.A series of radio frequency vacuum drying tests were then conducted on the pretreated lumber.The results showed that the number and the total length of surface checks decreased considerably in the samples pretreated under 105 ℃ atmospheric superheated steam for 31 hours.We also observed that the final moisture content distribution was more uniform with the pretreatment.Based on the drying cycle and drying quality,we concluded that the superheated steam pretreatment was feasible for mills even though it required a longer drying cycle.

Optimizing Poplar Veneer Dyeing Process by Response Surface Methodology

Abstract: The author investigated the influence on fast grown poplar veneer color caused by acid-based dye stains at various concentrations,times,and temperatures.She developed a quadratic regression model between the influencing factors and the color performance using a response surface method.She found the optimized parameters were: 0.52% dye concentration,4.2 hours dyeing time,and 72 ℃ temperature.The veneer color difference under the optimized condition was 62.54 NBS.

Color Fastness of Veneer with Nano-TiO_2 Modified Waterborne Coating

Abstract: This paper studied the process of preparing nano-TiO2 slurry and use the slurry to modify waterborne polyacrylate wood coating to improve their anti-ultraviolet performance. The effects of the processing nano-TiO2 slurry and the content of nano-TiO2 varnish on anti-ultraviolet performance were discussed. The coating films didn’t change their transparence and also showed good anti-ultraviolet resistance for both the dyed veneers and un-dyed veneers when nano-TiO2 content reached 1.5%.The nano-TiO2 modified films were better than commonly-used additive films which could change the chromatism by 1/3 to 2/5.

Dimensional Stability of Heat-Treated Lumber

Abstract: The authors evaluated the dimensional stability of lumbers with heat-treated,chemically modified and ammoniacal copper quaternary preservatives.The results showed that moisture absorption and volume expansion or shrinkage of the treated lumbers decreased.