The objective of this study was to determine the impact on termite feeding of wood sample size and species and test photoperiod in standard tests. Native species (Reticulitermes flavipes) and introduced species (Coptotermes formosanus) were tested in an American Wood-Preservers' Association E1 standard laboratory test. For testing involving treated wood, southern yellow pine was determined to be preferable to spruce based on its treatability and availability. Test blocks of 25 by 25 by 6 mm were deemed adequate for testing, with large blocks presenting difficulty with retrieval of termites to determine mortality and smaller blocks being consumed too rapidly by the termites in the test. Photoperiod comparisons were not significantly different for R. flavipes; however, C. formosanus indicated a preference for 100 percent darkness. Therefore, the recommendation is to maintain tests using each species in a 100 percent dark environment.Abstract
Planning and scheduling wood lumber drying operations is a very difficult problem. The literature proposes different methods aiming to minimize order lateness. They all make use of pre-established kiln loading patterns that are known to offer good physical stability in the kiln and allow full kiln space utilization. Instead, we propose a mixed integer programming (MIP) model, which can be used to generate loading patterns “on the fly.” This MIP model can be integrated into existing kiln drying operation planning/scheduling systems in order to improve their solutions. We show how this integration can be done by adapting a state of the art drying operations planning and scheduling methodology from the literature. We compare the solutions obtained by this system using the predefined loading patterns versus the solutions it generates if it is connected to our loading patterns generator MIP model. The study shows it is much better to dynamically create loading patterns than to use predefined ones, as most North American sawmills do.Abstract
As long-spanning timber floor elements attempt to achieve a meaningful market share, proof of serviceability continues to be a demanding task as international consensus remains unsettled. Initiatives to improve vibration levels are achievable, but a lack of confidence in the market is resulting in increases in margins for both manufacturers and contractors. State-of-the-art concrete alternatives are offered at less than half the price, and even though timber floors offer reduced completion costs and low carbon emissions, the market is continuously reserved. Cost reductions for timber floor elements to competitive levels must be pursued throughout the product details and in the stages of manufacturing. As new wood products are introduced to the market, solution space is increased to levels that demand computerized optimization models, which require accurate expenditure predictions. To meet this challenge, a method called item-driven activity-based consumption (IDABC) has been developed and presented in this study. The method establishes an accurate relationship between product specifications and overall resource consumption linked to finished manufactured products. In addition to production time, method outcomes include cost distributions, including labor costs, and carbon emissions for both accrued materials and production-line activities. A novel approach to resource estimation linked to assembly friendliness is also presented. IDABC has been applied to a timber component and assembly line operated by a major manufacturer in Norway and demonstrates good agreement with empirical data.Abstract
Cross laminated timber (CLT) is a mass timber product that is gaining popularity in construction within North America. CLT is made up of wood, a building material of biological origin. Therefore, these materials are at a risk of decay upon intrusion of moisture, a situation that could lead to loss of confidence in the material. Ensuring durability and optimum performance of building elements throughout their expected service life will require an understanding of the potential for decay and the possible consequences. This paper reviews the various possibilities of moisture intrusion in CLT, their potential effects on the physical and mechanical properties of CLT, and ultimately the associated biological decay risks. The paper concludes by enumerating variables that are critical and should be evaluated to completely understand decay in CLT panels, stemming from a thorough review of previous studies and methods used to evaluate decay in mass timber.Abstract
This article documents how the hardwood industry, in the absence of a standardized, industry-wide log grading system, has gone about grading and scaling hardwood logs by surveying mills, primarily in the Appalachian region. In total, 135 surveys were completed by respondents and returned via mail, with only 110 of those surveys considered usable for further analysis, after a thorough review of the individual surveys. Survey responses were grouped around annual production level, with three defined levels; ≤2.5 million board feet (MMBF), >2.5 and ≤8.0 MMBF, and >8.0 MMBF. Responding mills used some variation of a log grading system based on the number of clear faces on the log and the small end diameter of the log. The most common log rule used by mills in this study was the Doyle log rule, with over 75 percent using Doyle for scaling logs. Nearly 90 percent of all mills sampled graded logs without rolling the log to examine all four sides/faces. Half of all the sawmills surveyed pay the same price per thousand board feet (MBF) for butt logs and uppers. When asked if they would support the development of a standard log grading system, about two-thirds of the respondents (66%) indicated they would indeed support a standardized system for Appalachian hardwoods. These findings can help guide the development of a set of log grading standards for buyers and sellers in the Appalachian region and other parts of the world where hardwood lumber is produced.Abstract
Metasequoia-based three-layer parquet flooring (MPF) was prepared under the following conditions: hot-pressing temperature of 95°C, hot-pressing time of 7 minutes, hot-pressing pressure of 9 kg·cm−2, and addition of 200 g·m−2 urea-formaldehyde resin adhesive. The results showed that the moisture content, density, formaldehyde emission, static bending strength, and elastic modulus of the three kinds of parquet flooring were not much different than poplar-based multilayer parquet flooring (PPF) or fir-based three-layer parquet flooring (FPF) on the market. The thermal conductivity of the MPF was 0.195 W·m−1·K−1, which was the lowest among the three kinds of parquet flooring. The sound absorption coefficient of MPF under 11 frequency conditions in the range of 0.2 to 2 kHz was higher than that of PPF and FPF under the same frequency condition. The research results provide a reference value for the efficient use of low-quality M. glyptostroboides wood.Abstract
In the past, the wood products industry has often struggled with effectively marketing products to the public. With the increase of globalization and wood substitutions, the industry may need new ways to attract customers. Targeting younger customers who have recently joined the buyer's market may be a way to increase the industry's market share and customer base. A study was conducted to understand the millennial generation's (individuals born from 1980 to 2000) knowledge and perception of wood products. In 2018, an online survey was distributed to over 1,500 millennial-aged individuals and 1,479 usable survey responses were returned. Results indicate that respondents have a favorable perception of wood products and that there is potential to change uncertain or negative perceptions by providing informative facts about wood products. Approximately 71 percent of millennials indicated paper and pulp to be the most popular wood product, followed by lumber (51%) Responses also showed that 84 percent of respondents perceived wood as beautiful and 54 percent indicated it appealed to their sense of style. In terms of strength and durability, 46 percent of the respondents did not perceive wood to be as strong as steel. They were unaware of cross-laminated timber (74%) and its structural benefits and did not feel it was a safe product to use in tall buildings (54%). Millennial females and all millennials ages 18–20 held particularly stronger attitudes about wood products. The information gained from this research can be valuable when developing strategies to promote products and attract new customers.Abstract
Transverse modal analysis of timber panels is a proven effective alternative method for approximating a material's elastic constants. Specific testing configurations, such as boundary conditions (BC) and location of sensor and impact, play a critical role in the accuracy of the results obtained from the experimental assessment. This article investigates signal-specific details, such as the signal quality factor, that directly relate to the damping properties and internal friction as well as frequency shifting obtained from six different BCs. A freely supported (FFFF), opposing minor sides (shorter length) simply supported, and major sides (longest length) free (SFSF), as well as the reverse of the SFSF configuration with minor sides free and major lengths simply supported (FSFS) and all sides simply supported (SSSS) setup, are investigated. Variations into the proposed methods used to achieve an FFFF supported system are also considered. A combination of experimental testing in parallel with finite element analysis was conducted to re-create the setup that would be used within a manufacturing facility for nondestructive assessment of full-size cross-laminated timber panels. The differences between all BC configurations for their resonance frequency quality and location indicate that a freely supported system provides higher-resolution results, good comparison of less than 10 percent error with the finite element analysis and experimental results, and advantages in a simple experimental setup for the intended application.Abstract
Deck boards are key components in outdoor decks and balconies. The deck board market is shared primarily between solid-sawn and composite products. The focus of this article is solid-sawn wood deck boards, which are manufactured in North America as span-rated products following a policy promulgated by the American Lumber Standard Committee (ALSC). The latest revision of the ALSC span rating policy was approved in November 2020, and this article describes the technical basis for the changes. Distributed and concentrated design loads specified in the policy exceed building code minimum requirements. In addition, dynamic load amplification due to deck occupants is included in the new policy. Testing was performed to characterize the effects of partial fixity at joist supports caused by screw fasteners and was incorporated into the span rating methodology.Abstract
We examined timber price trends along the Mississippi roundwood supply chain. Quarterly statewide data from Timber Mart-South for pine sawtimber, pine pulpwood, mixed hardwood sawtimber, and pulpwood were obtained covering 1992 to 2018. Prices for stumpage, delivered logs, and timber conversion—measured as the difference between delivered wood and stumpage—were analyzed across products for the 27-year series, as well as three equally spaced 9-year periods (Period 1, 1992 to 2000; Period 2, 2001 to 2009; Period 3, 2010 to 2018). Flat delivered wood prices, increased rates for timber conversion, and declining pine sawtimber and pulpwood stumpage prices were revealed over the long term. Hardwood product prices, however, increased across their supply chains. Prices have generally become less volatile, particularly from Period 2 to Period 3, indicating an increasing degree of price homogeneity within each product's market. The exception to this was pine sawtimber, suggesting resource, locational, and/or market differences may have emerged for this product. The hardwood price trends supported, as appropriate, considering silvicultural options to allow this resource's continued growth. Declining price expectations for pine products call into question any strictly financial rationale for extending rotation length.Abstract
With the rise of new retail concepts, commodity trading has evolved from the traditional supply-to-consumer linear single-track relationship into a brand-new Internet platform-based S2b2c social networking system.1 Despite this, over 90 percent of wood product enterprises have an extremely limited understanding and application of this new kind of web service platform-based marketing systems. To reveal the impact of web service platforms on the growth of wood product enterprises, this study proposes an analytical framework that integrates the web service platform synergy, the social network synergy, and the corporate innovation capability. Using this framework, the effects of social network and web service platform synergies on the corporate innovation capability are analyzed, with a particular focus on exploring the mediating role of web service platform synergy between the social network synergy and the corporate innovation capability. Based on the questionnaire survey data of 489 large, medium, and small-wood product enterprises in the Pearl River Delta and the Yangtze River Delta regions, the following empirical results are derived through a combination of stepwise regression and Sobel test: (1) Web service platform synergy has a significant positive impact on the corporate innovation capability; (2) Social network synergy has a significant positive impact on the corporate innovation capability; (3) Social network synergy has a significant positive impact on the establishment of web service platforms; and (4) Web service platform synergy has a partial intermediary relationship between social network synergy and innovation capability, accounting for 34.05 percent of the total effect. The results of this study indicate that like social networks, web service platforms are the strategic resources of enterprises. In the context of open innovation, it is essential for the wood product enterprises to deeply integrate with the social networks and web service platforms, which helps enhance their innovation capability.
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