Treesearch

Cellulose nanocrystals (CNCs) are biobased materials with many desirable properties such as high aspect ratio, mechanical strength, crystalline nature, and biodegradability. This study developed a commercial-scale process model of CNC production from wood pulp using sulfuric acid treatment and evaluated its techno-economic and environmental performance with and without acid recovery. The results indicated that CNC produced with acid recovery process was financially more profitable with higher project net present values than without acid recovery process but required higher capital which...

For the existence of biorefineries, a consistent supply of sustainable crop residues is critical. Crop residue removal may adversely affect the overall sustainability, i.e., soil productivity and economics of crop residue removal. Therefore, it is necessary to develop a tool or method to estimate the sustainable removal of crop residues which is critical to various stakeholders including farmers, biorefinery, and policymakers. We proposed a robust deep ensemble machine learning(ML) model to estimate soil sustainability indicators [i.e., soil-erosion-factor(SEF), soil-conditioning-index(SCI)...

The 3rd Mass Timber Research Needs Assessment was held on September 20–22, 2022, at a location nearby the USDA Forest Service, Forest Products Laboratory. The workshop was co-sponsored by the Forest Products Lab and WoodWorks. The purpose of the workshop was to gather a diverse group of people with expertise in mass timber, in particular cross-laminated timber, to discuss and prioritize the research needed to move the mass timber industry forward in North America. The workshop was attended by more than 130 design professionals, researchers, manufacturers, industry leaders, and government...

Specific heat capacity of red oak and Douglas fir was measured from 0°C to 438°C using differential scanning calorimetry to provide input parameters for fire modeling. Techniques that allow for measurement of the standard heat capacity, excluding the effects of heat of reaction, were explored. Results show the specific heat capacity of wood becomes nearly constant with increasing temperature once pyrolysis starts. Furthermore, for both species of woods, the heat capacity values level out at a higher temperature than leaves, with correspondingly higher final specific heat capacity values.

As wood is exposed to high temperatures, pyrolysis begins, permanently altering the material properties as volatiles and char are formed. The rate at which char is formed is used to predict failure times for timber members and has been shown to be inversely related to the density of the wood. Because the density is a function of local exposure temperatures, it is inherently difficult to measure and typically is simplified to a single bulk value for either unmodified wood or the density of wood and char. Here, we report the use of two fast, simple density measurement techniques to characteri...

Brown rot fungi are primary decomposers of wood and litter in northern forests. Relative to other microbes, these fungi have evolved distinct mechanisms that rapidly depolymerize and metabolize cellulose and hemicellulose without digesting the more recalcitrant lignin. Its efficient degradative system has therefore attracted considerable attention for the development of sustainable biomass conversion technologies. However, there has been a significant lack of genetic tools in brown rot species by which to manipulate genes for both mechanistic studies and engineering applications. To...

Wood stiffness (modulus of elasticity, MOE) is an important property for conifer wood, with the variability in MOE largely being a function of both the specific gravity (SG) (wood density) and the angle of the microfibrils within the S2 layer of longitudinal tracheids. Rapid analysis techniques can be used together to quantify MOE; while SG can be determined with relative ease, this is not the case for microfibril angle, requiring expensive X-ray diffraction equipment. An alternative to microfibril angle is to measure longitudinal acoustic velocity. The objective of this study was to...

A new mold growth model was developed to aid in moisture risk assessment of wood-based building assemblies. This proposed simple model relies on several features common to existing mold growth models but combines them in a new way with improved predictive power. Structurally the model is based on a dose-response relationship. Hygrothermal conditions conducive to mold growth are represented using a mold germination isopleth, i.e., a critical relative humidity curve as a function of temperature. The dose at a given time step depends on the difference between surface relative humidity and the...

Cross-laminated timber (CLT) is an increasingly popular wood-based alternative for large building applications. CLT panels are typically not treated due in part to a perceived lack of efficient and effective methods for treating large panels and a lack of information on what effect treatment processes may have on the panels’ mechanical properties. We propose that treating CLT panels with borate solution, applied under vacuum in flexible bags, could provide a practical and effective option for providing preservative protection for interior applications. Samples were cut from commercially...

In September, month-over-month data were negative in several categories. Year-over-year data were similar. Single-family permits and starts decreased again, month-over-month and year-over-year. The impact of increasing borrowing costs and slow income growth combined with still elevated house prices resulted in a major obstacle for new and existing house sales. September was the eighth consecutive monthly decrease for existing house sales. Single-family construction spending decreased for the fourth straight month.