§ 149. Congestion mitigation and air quality improvement program (a) Establishment.— The Secretary shall establish and implement a congestion mitigation and air quality improvement program in accordance with this section. (b) Eligible Projects.— Except as provided in subsection (c), a State may obligate funds apportioned to it under section 104 (b)(2) for the congestion mitigation and air quality improvement program only for a transportation project or program if the project or program is for an area in the State that is or was designated as a nonattainment area for ozone, carbon monoxide, or particulate matter under section 107(d) of the Clean Air Act (42 U.S.C. 7407 (d)) and classified pursuant to section 181(a), 186(a), 188(a), or 188(b) of the Clean Air Act (42 U.S.C. 7511 (a), 7512 (a), 7513 (a), or 7513 (b)) or is or was designated as a nonattainment area under such section 107 (d) after December 31, 1997, or is required to prepare, and file with the Administrator of the Environmental Protection Agency, maintenance plans under the Clean Air Act (42 U.S.C. 7401 et seq.) and— (1)(A)(i) if the Secretary, after consultation with the Administrator determines, on the basis of information published by the Environmental Protection Agency pursuant to section 108(f)(1)(A) of the Clean Air Act (other than clause (xvi)) that the project or program is likely to contribute to— (I) the attainment of a national ambient air quality standard; or (II) the maintenance of a national ambient air quality standard in a maintenance area; and (ii) a high level of effectiveness in reducing air pollution, in cases of projects or programs where sufficient information is available in the database established pursuant to subsection (h) to determine the relative effectiveness of such projects or programs; or, (B) in any case in which such information is not available, if the Secretary, after such consultation, determines that the project or program is part of a program, method, or strategy described in such section 108(f)(1)(A); (2) if the project or program is included in a State implementation plan that has been approved pursuant to the Clean Air Act and the project will have air quality benefits; (3) the Secretary, after consultation with the Administrator of the Environmental Protection Agency, determines that the project or program is likely to contribute to the attainment of a national ambient air quality standard, whether through reductions in vehicle miles traveled, fuel consumption, or through …

A. Federal Highway Administration

ion between fibre lignin and laccase in qualitative difference in temporal phases than laccase does alone. Resulting distinguished lignin modifications may have consequences for subsequent fibre behaviour (Barsberg 2002). Lund & Felby (2001) applied a range of mediators in laccase-modification of spruce and pine fibres and found ABTS and PPT (phenothiazine-10-propionic acid) to be effective in enhancing wet tensile strength of paper handsheets made from the pulp. Similar results were obtained with ABTS by Elegir et al. (2005, 2007). Treatment of fibres with laccase and gallic acid were also reported to change wet tensile strength (Chandra et al. 2004b), indicating that laccase-mediator system can influence properties of the fibre surfaces. Various mediators are therefore currently tested in MDF production with laccase in order to achieve higher reactivity between laccase and lignin and better board properties (Müller et al. 2006). The unfortunately limited availability of cheap and non-toxic mediators is of course a restricting factor in such approaches (Rochefort et al. 2004, Morozova et al. 2007). So far, in laccase-mediated bleaching of lignocellulosic fibres 1-hydroxybenzotriazole and the lignin-derived phenols acetosyringone and syringaldehyde acid have been positively tested as mediators whereas negligible effects were seen with p-coumaric acid (Ibarra et al. 2006, Camamero et al. 2007, Gutiérrez et al. 2007). Oppositional ABTS-mediated depolymerisation and polymerisation effects on kraft lignin samples (González Arzola et al. 2006, Hernández Fernaud et al. 2006) imply that the doses and times of mediators and enzymes applied have to be expected to play an important role in activating of fibre material. In line with this, dosages of 4-hydroxybenzoic acid were most influential in laccase-mediated modification of paper pulp (Chandra et al. 2004a). Further to applications of mediators to improve mechanical properties by laccase action, recent studies suggest that a successive xylanase and laccase treatment with or without mediators might also be useful in efficiently modifying fibre surfaces at least in paper production. As the gallic acid mediator treatment, successive xylanase-laccase treatment has been reported to increase the wet tensile strength of paper (Chandra & Raugaskas 2005, Kapoor et al. 2007). 2-component adhesives based on lignin and enzymes In the wood composite industry, addition of lignosulphonates (spent sulphite liquor) or kraft lignins from sulphate pulping, to conventional PF resins is targeted at replacing parts of the phenol component made from petrochemicals (e.g. see Roffael & Rauch 1971, Shen 1974, Nimz 1983, Ayla & Nimz 1984, Danielson & Simonson 1998a,b, Tejado et al. 2007; further reading in Chapter 16 of this book). Formaldehyde from the PF resin may act in such mixtures as a cross-linker between the reactive sites of the technical lignins and the synthetic phenol binder (Kuo et al. 1991, Vázquez et al. 1999, El Mansouri & Salvadó 2006, 2007). As first

/pdf/wood-production-wood-technology-and-biotechnological-impacts-5gpvoylcbz.pdf

Wood production, wood technology, and biotechnological impacts

Two ultrasonic technologies, acoustic emission and acousto-ultrasonics, are reviewed in terms of characteristics and applications to wood and wood-based materials. The background is given on the two technologies, including the effect of wood on wave propagation and sensitivity to defects and other properties. The factors that affect wave injection and processing are reviewed for each technology. Four applications are given as examples: particleboard springback, creep/creep-rupture, adhesive curing, and deterioration detection. Recent developments in the technologies are discussed.

Overview of the use of ultrasonic technologies in research on wood properties

Effect of steam explosion treatment on characteristics of wheat straw.

The building sector, including building operations and materials, was responsible for the emission of ∼11.9 gigatons of global energy-related CO2 in 2020, accounting for 37% of the total CO2 emissions, the largest share among different sectors. Lowering the carbon footprint of buildings requires the development of carbon-storage materials as well as novel designs that could enable multifunctional components to achieve widespread applications. Wood is one of the most abundant biomaterials on Earth and has been used for construction historically. Recent research breakthroughs on advanced engineered wood products epitomize this material's tremendous yet largely untapped potential for addressing global sustainability challenges. In this review, we explore recent developments in chemically modified wood that will produce a new generation of engineered wood products for building applications. Traditionally, engineered wood products have primarily had a structural purpose, but this review broadens the classification to encompass more aspects of building performance. We begin by providing multiscale design principles of wood products from a computational point of view, followed by discussion of the chemical modifications and structural engineering methods used to modify wood in terms of its mechanical, thermal, optical, and energy-related performance. Additionally, we explore life cycle assessment and techno-economic analysis tools for guiding future research toward environmentally friendly and economically feasible directions for engineered wood products. Finally, this review highlights the current challenges and perspectives on future directions in this research field. By leveraging these new wood-based technologies and analysis tools for the fabrication of carbon-storage materials, it is possible to design sustainable and carbon-negative buildings, which could have a significant impact on mitigating climate change.

Emerging Engineered Wood for Building Applications.

Localized modulus of elasticity (MOE) and tensile strength (T) were modeled for two visual grades of Douglas-fir laminating lumber. These material property models will be used as input to other structural analysis models that predict the strength and reliability of glued-laminated beams. Tensile strength and MOE are important material properties since most glued-laminated (glulam) timber beam failures initiate in the tension zone. Localized MOE and T exhibited significant within-piece variability as well as between-piece variability. These localized properties were also spatially correlated. A method that uses a transformation of the multivariate normal distribution was developed to simulate these localized properties for lumber up to 8-ft long. This method preserved the probability distributions of localized MOE and T as well as the spatial correlations between the localized property values. Procedures were described for expanding the model to simulate boards of any length. The method was also used to simulate long-span tensile strength. Mean simulated tensile strengths compared favorably with test results. Test results also confirmed a reduction in tensile strength as test span increased.

/pdf/stochastic-model-for-localized-tensile-strength-and-modulus-ap9zc24tp2.pdf

Stochastic Model for Localized Tensile Strength and Modulus of Elasticity in Lumber

Sawmills can implement quality control procedures to lower their lumber target sizes and/or sawkerf widths, but the economic benefit of such programs has been uncertain. A methodology using sawmill simulation to estimate the value and volume recovery from changes in sawkerfs and target sizes is demonstrated. A specific example for an interior British Columbia sawmill producing dimension lumber is described. Reductions in target sizes and sawkerfs were shown to significantly increase mill revenues. Target size and sawkerf reductions were found to have a much larger effect on sawmill revenue than on volume recovery. Reductions in green target sizes are shown to have a significantly larger impact on mill net revenues and recovery than sawkerf reductions. It was also found that producing 1-inch lumber in the product line significantly increases lumber recovery, but has a minimal effect on mill net revenue. Equations were developed that predict the net effect in revenue and volume recovery of specific changes in target size and sawkerf for the study mill.

The influence of sawkerf and target size reductions on sawmill revenue and volume recovery.

International Particleboard/Composite Materials Symposium Proceedings

The objective of this paper is to present a critically refracted longitudinal wave (L CR ) technique that allows localized ultrasonic inspection of wood parallel-to-grain by accessing only a single side of the material. The L CR technique has been widely applied to other materials, but not to wood. The chief advantage of the L CR technique is that ultrasonic waves can be transmitted through wood at frequencies much higher than previously possible (up to 1.5 MHz), leading to potential gains in sensitivity over lower frequency methods. The L CR technique was verified using southern pine lumber. Transducer beam characteristics were examined and the influence of growth ring angle was observed. Ultrasonic wave energy was found to travel near to the inspection surface. Further, localized growth ring angle was significantly correlated to signal amplitude and frequency.

/pdf/a-critical-angle-ultrasonic-technique-for-the-inspection-of-l7ezchdxf5.pdf

A Critical-Angle Ultrasonic Technique for the Inspection of Wood Parallel-to-Grain

Low-rise buildings are typically designed with shear walls and horizontal diaphragms to resist lateral load during windstorms and earthquakes. Although seismic performance and lateral load resistance behavior are generally well-understood for light-frame wood construction, this is not true for log construction. Research is needed to characterize log shear wall behavior subject to racking loads, and to develop recommendations for designing log walls to resist lateral loads from seismic or wind events. Monotonic and reverse-cyclic tests were conducted on log shear walls with 1:1, 2:1, and 4:1 aspect ratios. These walls showed higher resistance than conventional light-frame shear walls and similar hysteretic behavior to concrete and masonry shear walls. Log walls withstood large in-plane displacements without significant load reduction using lateral bracing typical of that used for light-frame wall testing; however, the test procedure would be improved by providing full-wall support to resist out-of-plane displacements of log shear walls. Design recommendations were developed based on the experiments reported herein.

Performance of Log Shear Walls Subjected to Monotonic and Reverse-Cyclic Loading

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