Six wood species generally accepted to represent a range of natural durability were exposed in American Wood Protection Association (AWPA) E7-09 (ground-contact) and AWPA E25-08 (aboveground) decay tests at field sites located near Maple Ridge, British Columbia, and Petawawa, Ontario, in Canada and Gainesville, Florida, and Hilo, Hawaii, in the United States. Variables examined included comparisons of sapwood to heartwood, old growth to second growth, and effect of a protective coating. The tests began between October 2004 and February 2005. Results are reported after 5 years of exposure. Ground-contact decay rates were fastest at sites in Florida and Hawaii. Yellow cedar (Callitropsis nootkatensis (D. Don) Örsted), western red cedar (Thuja plicata Donn ex D. Don), and eastern white cedar (Thuja occidentalis L.) had the highest condition ratings (least decay) for this measure after 5 years of exposure, followed by western larch (Larix occidentalis Nutt.), Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), and then tamarack (Larix laricina (Du Roi) K. Koch). The aboveground decay rate was highest in Hawaii. For this measure, yellow cedar and western red cedar again had the highest average decay ratings (least decay) after 5 years of field exposure, followed by Douglas-fir, western larch, and tamarack. Eastern white cedar did not fit neatly into this pattern. It was durable at three of the four sites but failed rapidly in Hawaii. Sapwood appeared to have a larger impact on aboveground decay than on ground-contact decay. No substantial difference was found between old-growth and second-growth decay rates.
A comparison of liquid water absorption in uncoated Norway spruce (Picea abies L.) claddings before and after 1 year of outdoor weathering was performed. The study was based on 150 specimens from two sites with high-productive forest and two sites with low-productive forest in southern Norway. The specimens included inner and outer boards; density, annual ring width, and proportion of heartwood were recorded. Water absorption increased after weathering. The relative change of short-term absorption was larger for outer boards than for inner boards, whereas it did not vary between origins. The outer boards also had more cracks than the inner boards after weathering. The differences between inner and outer boards were explained by different heartwood proportion and different annual ring orientation. The variability of short-term absorption increased after weathering since the sample groups with the highest initial absorption also had the largest increase after weathering. The change of long-term absorption did not vary between inner and outer boards or between origins.
One of the frequent signs of early failure in semitransparent wood coatings is colonization by “black stain” fungi, such as Aureobasidium pullulans. A laboratory method evaluating the ability of various wood coating formulations to inhibit the growth of black stain fungi on artificially weathered, coated wood in petri dishes was developed. Meaningful results were obtained after only 6 weeks of incubation. Selected biocides and biocide combinations formulated in a semitransparent coating including selected combinations of diiodomethyl-p-tolylsulfone, 3-iodo-2-propynyl butylcarbamate (IPBC), propiconazole, tebuconazole, thiabendazole, fludioxonil, chlorothalonil, oxine copper, copper metal, and naphthoquinone were evaluated. Combinations of propiconazole with IPBC and propiconazole with IPBC and thiabendazole were most effective in this test. Further work is needed to evaluate the use of other coatings and test fungi with the laboratory test method and to evaluate the performance of the best-performing biocides in field exposures.
The potential for high intensity ultrasound for the phytosanitation of wood products was tested using decay (rot) and mold fungi and termites. The treatment was not effective in killing these organisms in wood.
The influences of temperature, heating rate, purge gas type, and flow rate on the yield of chars produced from pyrolyzing southern pine chips were investigated. Pyrolysis temperatures were between 450°C and 1,000°C, with heating rates of 0.5°C/min, 1.0°C/min, 10°C/min, 30°C/min, 50°C/min, and 100° C/min. Purge gases, nitrogen (N2), hydrogen (H2), and N2–H2 mixture (10% H2), were used at flow rates from 100 to 1,000 mL/min. Pine char yield decreased as temperature, heating rate, or purge gas flow rate increased. Two regions with significantly different decrease rates of pine char yield can be identified for temperature or heating rate as they increase. The yield decrease rate turning points were 550°C and 10°C/min for yield-temperature and yield-heating rate charts, respectively. The pine char yield was lowest when hydrogen was the purge gas and highest with nitrogen.
The sanding of black spruce wood prior to coating application was optimized for feed speed and grit size. As feed speed increased, the surface roughness and the surface energy of the samples increased. For the different sanding programs, reductions of the surface roughness and the contact angles were observed with a finer grit abrasive. The initial pull-off strength was statistically similar regardless of the feed speed and grit size. However, both the feed speed and the grit size affected coating adhesion following the accelerated weathering treatment. Because there was no correlation between the surface quality parameters and the pull-off strength, the latter had to be measured to determine coating performance on black spruce wood. In the present work, a two-stage sanding program combined with a feed speed of 17 m/min resulted in good surface quality and pull-off strength.
Structural honeycomb panels consist of a lightweight, often paper, honeycomb column core between two thin, stiff face sheets, which results in a very light structure with high strength and stiffness. These panels have long been used in the shipping and aerospace industries and for furniture components in Europe. The wider adoption of honeycomb panels by Canadian furniture manufacturers is hampered by a lack of experience and technical data on their manufacture, properties, and performance. This study attempts to address this missing information with a series of experiments to test the influence of Kraft paper honeycomb type, orientation, cell wall height, and face sheet type on sandwich strength properties (flexural, shear rigidity, and panel deflection). Failure of sandwich panels occurs by buckling of the honeycomb cell walls under the load point; panel load-bearing capacity is significantly improved by the use of stiff face sheets such as plywood. The strongest and stiffest panels are made with small honeycomb cells (16 mm). The extra cost and bulk associated with using paper-laminated pre-expanded honeycomb is not matched by increased bending strength and is therefore unnecessary. Bending strength is significantly enhanced by aligning the honeycomb so that the nodes and ribbon direction are perpendicular to the long axis (loading direction) of the panel due to the ability of the core to flex and conform to the curvature of the face sheets under load. The results from this study offer insights that furniture manufacturers may use to fabricate and potentially improve the properties of honeycomb sandwich panels.
Effects of changes on industry sector data for the Mississippi logging industry were examined to determine importance to and economic impact in that state's economy. Quantification, evaluation, and improvements upon current methodology of data and data collection for use in the Impact Analysis for Planning (IMPLAN) software model to more accurately reflect and support IMPLAN inputs and outputs were also determined. Economic impact estimates derived from model default data were compared with estimates derived from survey-based expenditure data collected within the state. The top 20 output sectors in the state economy resulting from logging expenditures were determined. In turn, new data were acquired to replace 4 of the top 20 sectors and new economic impact estimates derived. Economic impact assessment results on the model default data showed total economic impacts of $2.309 billion and $2.489 billion in industry output in 2006 and 2009 dollars, respectively. Total economic impacts generated using survey-based data from a sample of 33 loggers were $129.310 million and $131.747 million in 2006 and 2009 dollars, respectively. Total economic impacts generated by replacing 4 of the top 20 sectors from 33 loggers were $109.979 million in 2009 dollars. While this study was limited by a small sample size in regard to making statewide estimates, results indicated that limitations within the IMPLAN model further manifest themselves when implementing economic impact assessments. Rather than just relying on the default model data, more localized data should be collected when doing studies of this type.
An optimal three-dimensional visualization system was developed for edging and trimming of rough lumber in central Appalachia. ActiveX Data Objects were implemented via MS Visual C++/Open Graphics Library to manipulate board data at the backend supported by a relational data model with four data entity types: Board, Shape, Defect, and Defect Type. Exhaustive search procedures and a dynamic programming algorithm were used to achieve the optimal edging and trimming solution. A lumber grading module was also developed to grade hardwood lumber based on National Hardwood Lumber Association grading rules. The system was validated through comparing the total lumber values generated by the system with those generated by six local sawmills. A total of 360 boards were measured for board dimensions, defects, shape, wane, and the results of edging and trimming. Results indicated that the lumber value and surface measure gained in these six sawmills could be increased, on average, by 21.37 and 6.1 percent, respectively, using the optimal edging and trimming system. The optimal edging and trimming system not only can be used as a training tool but also can be installed on a field PC to aid the edging and trimming process.
This study presents a systematic approach of streamlining an upholstery furniture engineering process based on a case study in one of the largest export-oriented furniture manufacturers in China. The approach encompasses an analysis of the current state of the engineering process and the proposal of a lean future state value stream map (VSM). The current state analysis includes the definition of the product family, analysis of current customer demands, and the definition of the process metrics of the engineering process. Data were collected during a half-month visit to the furniture plant in China. Results from the current state VSM show that the value-added ratio of the current engineering process is 26.0 percent. Many engineering steps present deficiencies, such as the processes of creating drawings, compiling mass production documents, checking and signing off on engineering documents, creating CNC programs, and generating packaging files. After the current state VSM, it is found that unpredictable process cycle time and expediting engineering change orders are two major problems in the current engineering process. Based on current state VSM, the research focuses on countermeasures to solve the root causes of the major problems and proposes the best practices for the future VSM.