Treesearch

Global demand for construction materials from population growth and higher standards of living stresses the climate. Natural solutions such as renewable construction materials from wood aid in sustainable growth and decrease our environmental footprint. Wood can be used along the entire supply chain in producing these renewable products. Lower quality logs, sawmill residues, and construction waste are forms of wood resources processed to make engineered wood products such as cellulosic fiberboard. These engineered wood products are used in building construction and can store carbon for...

When a new engineered wood adhesive is developed for use in a fire-rated assembly, it must first pass a full-scale fire test, for example, a test in accordance with ASTM E119 in the United States. Although full-scale tests serve as the necessary entry to the marketplace, they are extremely costly and reflect the performance of the entire assembly and not just the adhesive. As a result, it is difficult to quantify differences in adhesive performance under elevated temperatures or fire conditions with these tests. Here, we present the results from a new test method developed at the USDA...

In this study, cellulose nanocrystals (CNCs) with PEG grafts of various lengths (1 k, 2 k, 5 k, and 10 kDa) were prepared via a polydopamine (PDA) mediated method in the aqueous solution. The prepared CNC-PEGs were further used to reinforce the polyvinyl alcohol (PVA) at the loading of 0, 1, 3, 5, and 7 wt% in order to demonstrate the effects of the PEG length on the properties of the PVA/CNC nanocomposites. PEG surface modification resulted in simultaneous improvements in stiffness and toughness. The graft lengths have noticeable impacts on the properties of composites. The shorter graft...

The aim of this research was to explore the potential of acoustic impact test to evaluate the condition of hardwood logs in regard to internal decay, void, crack and defect ratio using an acoustic signal separation and enhancement algorithm. Longitudinal acoustic signals were obtained from 15 logs of four hardwood species through acoustic impact testing. The defect components were separated from the acoustic response signals and enhanced based on the autoregressive minimum entropy deconvolution (AR-MED) method, and from which the kurtosis was derived and used as the global feature parameter...

Carbon foams have been prepared using Kraft lignin as the solely resource. No catalysts, foaming/blowing agents, surfactants, and/or crosslinking agents are used for the foam preparation. The process includes pressing carbon foam precursors into molds followed by formation of lignin foam through heating and carbonization/graphitization of the lignin derived foams. The resultant lignin carbon foam (LCF) has an open-cell structure with densities ranging from about 0.18 g/cm3 to 0.68 g/cm3. The compressive strengths of LCFs increase with increasing of bulk density, from 7.03 ± 1.25 MPa of...

This study evaluated the mechanical properties of hybrid (mixed-species) cross-laminated timber (CLT) panels made of low-value sugar maple (Acer saccharum) and white spruce (Picea glauca). The modulus of elasticity (MOE) of the laminations was measured with a nondestructive method. Three-layer hybrid CLT panels with layup combinations of sugar maple–white spruce–sugar maple and white spruce–sugar maple–white spruce were prepared to evaluate the effects of layups on the performance of the CLT samples. The mechanical properties of hybrid CLT panels were evaluated with different layups and...

Aggregate housing data were overwhelmingly positive in March. Total March housing starts achieved their greatest level since July 2006. Total and single-family permits rebounded strongly as well. Houses under construction and housing completions also attained their highest levels in 13 years. New single-family house sales recorded significant gains. Existing house sales were negative month-over-month, and housing doyens attributed this to a lack of inventory. Total and single-family construction spending were positive month-over-month and year-over-year. In sum, private residential...

The year-over-year housing data for April were all robustly positive. However, month-over-month declines were reported for total and single-family housing starts, total and single-family permits, total housing completions, and new single-family and existing house sales. Total and single-family houses under construction and total and single-family construction spending were positive month-over-month.

In 2017, a moisture monitoring study was initiated on an eight-story, mass timber building located in Portland, Oregon. A detailed description of the monitoring program and initial monitoring results from the first year of the program were published previously. It was discovered that by the end of Year 1, some of the mass timber components had not dried below 19% moisture content (MC). This technical note is a follow-up to the original paper to examine how the building changed over its first 3 years after construction. All of the locations monitored over 3 years have reached stable...

Wood extractives, solvent-soluble fractions of woody biomass, are considered to be a factor impeding or excluding fungal colonization on the freshly harvested conifers. Among wood decay fungi, the basidiomycete Phlebiopsis gigantea has evolved a unique enzyme system to efciently transform or degrade conifer extractives but little is known about the mechanism(s). In this study, to clarify the mechanism(s) of softwood degradation, we examined the transcriptome, proteome, and metabolome of P. gigantea when grown on defned media containing microcrystalline cellulose and pine sapwood extractives...