Wood and Fiber Science (E-Journal)
Not a member yet
2592 research outputs found
Sort by
SURVEY RESPONSE RATES IN THE FOREST PRODUCTS LITERATURE FROM 2000 TO 2015
Get PDFA literature analysis was conducted to synthesize typical response rates from forest-products-industry-based survey studies published from 2000 to mid-2015. One hundred and ninety-five surveys published in several forest products and forestry journals and proceedings (mostly North American based) were analyzed. Overall, the typical response rate was found to be about 26.0% (median) to 31.6% (mean). The median survey size in terms of number surveyed was 543.0, and the median for responses received was 131.5. Several factors were found to influence response rates and numbers surveyed. The results indicated that response rates were highest for surveys conducted at the regional or international level, that were interview based, and that were geared toward consumers. The majority of the surveys conducted were mail based (79.0%) and were directed at manufacturers (51.8%) followed by loggers (15.4%) and engineers (14.4%). There was no indication that the year of publication had an effect on observed response rates. Most studies reported testing for nonresponse bias (64.4%), with early vs late respondent comparisons being the most common method used. These results can be used as a benchmark for whathave been typical response rates for survey-based research in the forest products industry.
LOWER TOLERANCE LIMIT APPROACH TO EQUATION-BASED RATIONAL DESIGN VALUES FOR L-SHAPED MORTISE AND TENON JOINTS
Get PDFStatistical lower tolerance limits (LTLs) were computed for the ratios obtained by dividing the test values for 360 L-shaped rectangular mortise and tenon joints consisting of 72 different configurations of five specimens each by the corresponding values estimated by a nonlinear-regression expression fitted to the test data. LTLs were computed for the resulting ratios at the 75∣75, 90∣75, 75∣90, and 90∣90 confidence∣proportion levels. At these levels, the corresponding LTLs amounted to 88.1%, 87.4%, 75.8%, and 74.9%, respectively, of the estimates. The percentages of values that fell below the above stated LTLs were 24.2%, 23.3%, 8.3%, and 7.5%. On average, 53% of the test values below a given tolerance limit fell in the range of 90-99% of that limit. Differences between 75∣75 and 90∣75 limits as well as between 75∣90 and 90∣90 limits were sufficiently small that the greater confidence level appears desirable. This study is too limited in scope to suggest the appropriate confidence∣proportion level that might be used in determining design values for joints as a percentage of estimated values, but it does raise the question and emphasizes the importance of determining what percentage of failure is acceptable along with what level of confidence is appropriate for furniture design.
DYNAMIC RESPONSE OF WOOD BASED BIO-COMPOSITIES UNDER HIGH-STRAIN RATE COMPRESSIVE LOADING.
Get PDFThis paper focuses on obtaining a high-strain compressive response of various wood-based biocomposites. The dynamic stress-strain curves of various wood-based biocomposites at three different strain rates were obtained using a split-Hopkinson pressure bar (SHPB) and were compared. The specific energy of each composite sample at three different strain rates was obtained and compared. It was found that 4% methylene diphenyl diisocyanate (MDI), 4% processed corn starch (CS) 600S had the highest specific energy for all nine different kinds of wood-based biocomposites tested in this study. The panel produced with 4% MDI and formed at the highest pressure (mat pressure of 1523 psi) consistently had the highest yield strength in the Hopkinson bar tests conducted at 10 psi (560-1053 s-1, was the range of strain rate achieved under this pressure), 15 psi (727-1380 s-1, was the range of strain rate achieved under this pressure), and 20 psi (766-15837 s-1, was the range rate of strain achieved under this pressure). When comparing samples that were formed under similar mat pressures, the material formed at the longest curing time (600 s) had the highest yield strength at 10 psi. At similar mat pressures, when tested at 15 psi, the material formed from 2% CS and 4% MDI at 140 s had the highest yield strength. At similar mat pressures, when tested at 20 psi, the material formed from 2% CS and 2% MDI at 140 s had the highest yield strength. Samples containing CS had a high average strain rate when compared with other wood samples, and this shows that the CS contributed to the high stain rate of the material.
DEVELOPING A RAPID TEST METHOD FOR MEASURING VOLATILE ORGANIC COMPOUNDS FROM THREE-LAYER PARQUET WITH MICROCHAMBER
Get PDFThe volatile organic compounds (VOCs) released from wooden floors can cause poor indoor air quality; therefore, the 1-m3 chamber method is usually used with wooden floors to test for those VOC emissions. However, that method is costly, time consuming, and has limited application in various test environments. In this study, a rapid test method was used to detect VOC emissions from three-layer parquet under various test conditions and to compare the results with those from the traditional 1-m3 chamber method. The VOC constituents and mass were confirmed by gas chromatography-mass spectrometry. Results showed that the VOCs emitted from three-layer parquet comprised aromatic hydrocarbons and esters. The optimum conditions when sampling VOCs emitted from three-layer parquet using the rapid test method were 80°C, 60% RH, and 0.2 m3·m2·h1 area-specific airflow rate. The time required for the total VOC emissions to reach a state of equilibrium was 10 da for the rapid test method, which was 18 da shorter than the time required by the 1 m3 chamber method. Both methods detected the same VOCs and the R2 of two methods was 0.9598, which, being close to one, showed good correlation. Therefore, the rapid test method may be helpful in improving efficiency and reducing the costs associated with detection of VOCs released from wood flooring.
STRESS ANALYSIS OF CELLULOSIC-MANURE COMPOSITES
Get PDFAbility to determine stresses in loaded, perforated cellulosic-manure composites from recorded temperature information was demonstrated. Being able to stress analyze such green materials addresses several societal issues. These include providing engineering members fabricated from materials that are suitable for developed and developing nations, relieving a troubling by-product of agricultural regions and reducing demands on our landfills. Most engineering applications of these materials necessitate knowing their structural integrity eg capability to evaluate stresses.
EFFECT OF LANDFILL BURIAL ON CONDITION OF WOOD: PRELIMINARY TESTS
Get PDFThe effect of landfill exposure on residual levels of cellulose, hemicellulose and lignin was investigated on wood materials removed from differing depths in a 5 year old landfill cell in western Oregon. There was little evidence of change in the levels of these components with increasing landfill cell depth in softwood lumber, softwood plywood, or hardwood lumber. The results confirm studies at other landfills showing that wood degradation rates under anaerobic conditions in landfills are much slower than predicted and that models to predict these rates need to be modified
INVESTIGATING SYNERGISTIC INTERACTION OF BAMBOO AND TORREFIED BAMBOO WITH COAL DURING COCOMBUSTION
Get PDFTo investigate if there is synergistic interaction between bamboo with coal, or between torrefied bamboo with coal during cocombustion, bamboo and torrefied bamboo separately were respectively uniformly mixed with coal and the weight percentage of bamboo or torrefied bamboo in the mixture were 10%, 20%, 30%, and 40%. The combustion behaviors of blends were characterized using thermogravimentric analyzer at heating rates of 10°C/min, 20°C/min, 30°C/min, and 40°C/min. Results showed that the combustion process of bamboo and coal combustion was separated during cocombustion, and the higher temperature zone corresponding to coal combustion had a higher activation energy. Cocombustion of torrefied bamboo and coal had a combustion zone. Combustion characteristics gradually increased with increase in heating rates and decrease in mixing ratios. Theoretical combustion characteristics obviously shifted to higher temperatures, indicating synergistic interactions between bamboo/torrefied bamboo and coal. Cocombustion of torrefied bamboo and coal was more feasible with a stabler combustion process. The results might be helpful to promote bamboo resources as a blend fuel for co-firing application with coal
EFFECT OF CHEMICAL TREATMENT ON FIRE-RETARDANT PROPERTIES OF MEDIUM DENSITY COIR FIBER BOARDS
Get PDFCoir fiber is a natural fiber extracted from the husk of coconut and medium-density panel boards made from coir are being investigated worldwide for their ability to substitute wood. Fire-retardant properties of the panel boards made from coir fiber need to be enhanced for its wider acceptance. In the present study, panel boards have been subjected to chemical treatment with an aqueous solution containing preservative boron compounds and the samples after treatment showed very significant improvement in resistance to flammability, flame penetration, and reduced rate of burning. The test for limiting oxygen index showed reduced values of ignitability, suggesting the use of the earlier methods to enhance the fire-retardant properties of coir fiber–based panel boards and use of the panels as substitute for wood-based applications.
Influence of Calcination Temperature on the Structure and Visible Light Photocatalysis Performance of Mn–TiO2-Loaded Wooden Activated Carbon Fibers
Get PDFMn–TiO2-loaded wooden activated carbon fibers (Mn/TiO2-WACF) were prepared through sol–gel and impregnation methods and characterized by X-ray diffractometer, scanning electron microscope, Fourier transform IR spectrometer, and automatic adsorption apparatus to observe the influence of load calcination temperature on its morphological structure and visible light photocatalysis performance. Results showed that Mn doping elevated the phase transformation temperature (650 °C–750 °C) of TiO2 in Mn/TiO2-WACF; the particle size of anatase TiO2 in the sample gradually enlarged with the increase of calcination temperature. The N2 adsorbing quantity of Mn/TiO2-WACF sample initially increased and then decreased as calcination temperature increased, and 650 °C became the turning point of its N2 adsorbing quantity. The degradation methylene blue solution for Mn/TiO2-WACF sample under visible light gradually decreased with the increase of calcination temperature, and the methylene blue solution degradation by the sample obtained under 450 °C calcination temperature reached 93%
Properties of Pine Scrim Lumber Made From Modified Scrim
Get PDFIn this study, scrim from small-diameter southern pine bolts was treated with melamine formaldehyde (MF), phenol formaldehyde (PF), and furfuryl alcohol (FA) at different loadings and formed into 25-mm-thick pine scrim lumber (PSL) panels. MOE, MOR, work to maximum load (WML), internal bond (IB), toughness, water absorption, thickness swelling, 5-h tangential dynamic swelling, and termite resistance were evaluated. Results showed that samples treated with 5% MF resin had the highest MOE, MOR, and WML values (15.3 GPa, 54.2 MPa, and 25.4 kJ/m3, respectively), whereas those treated with 10% MF resin had the highest IB and edgewise toughness values of 390 kPa and 12 N m, respectively. With respect to dimensional stability, samples treated with 20% FA had the lowest swelling values after 24-h submersion in water (anti-swelling efficiency [ASE] . 36.8%), and the lowest water absorption value (27.5%). Five-hour tangential dynamic swelling test revealed much higher dimensional stability for furfurylated samples (ASE >45%). As for termite resistance, both untreated and treated PSL had little weight loss (1.10-1.56%), high visual rating (8-9.3/10), and high mortality (100%) in laboratory tests. MF and FA impregnation proved to be feasible modification methods in this study.