Treesearch

Lignin valorization is significantly influenced by the degrees of lignin condensation measured by the amount of cleaved βeOe4 ether linkages and interunit CeC linkages formed during biomass fractionation. To minimize the cleavage of aryl ether and formation of CeC linkages, a p–toluenesulfonic acid (p–TsOH)/choline chloride (ChCl) solvent system with hydrotropic properties was evaluated. The ChCl was chosen to control the H+ concentration of the p–TsOH/ChCl solvent system. Compared with p–TsOH/H2O, the degradation of βeOe4 was kept in a similar rate during p–TsOH/ChCl fractionation;...

Poplar trees can be grown on marginal land to conserve water and recycle nutrients, but the wood has poor mechanical properties for structural applications. This study evaluated the feasibility of densifying poplar wood through delignification to improve mechanical properties. Delignification was conducted using a commercial soda pulping process under various NaOH concentrations of 0–6% with a reduced liquor-to-wood ratio of 3, along with a novel hydrotropic fractionation process using maleic acid. Delignified wood was pressed with or without stop bars at a low pressure of 1 MPa at 150 °C...

Pacific Northwest policy makers are excited about the emergence of mass timber into U.S. construction markets as the product potentially creates local manufacturing jobs while utilizing Douglas fir growing sustainably in the region. This study assessed regional economic impacts generated by mass timber high-rise construction in Oregon. Economic impact estimates were derived using a regionally specific input-output model combined with analysis-by-parts methodology. Financial data from Portland’s 12-story Framework building, estimated using RSMeans software, provided purchasing information....

Brown rot (BR) decay mechanisms employ carbohydrate-active enzymes (CAZymes) as well as a unique non-enzymatic chelator-mediated Fenton (CMF) chemistry to deconstruct lignocellulosic materials. Unlike white rot fungi, BR fungi lack peroxidases for lignin deconstruction, and also lack some endoglucanase/cellobiohydrolase activities. The role that the CMF mechanism plays in “opening up” the wood cell wall structure in advance of enzymatic action, and any interaction between CMF constituents and the selective CAZyme suite that BRs possess, is still unclear. Expression patterns for CMF redox...

In April, the vast majority of month-over-month and year-over-year categories were negative. The substantial declines are attributed to the impact of the Covid-19 virus. On a month-over-month basis, single-family under construction and new single-family sales were positive. Year-over-year, total multifamily housing under construction and private residential and single-family construction spending indicated improvement.

To evaluate the reliability of lumber structures, good models for the strength and stiffness distributions of visual and machine stress–rated (MSR) grades of lumber are necessary. Verrill and coworkers established theoretically and empirically that the strength properties of visual and MSR grades of lumber are not distributed as 2-parameter Weibulls. Instead, strength properties of grades of lumber must have “pseudo-truncated” distributions. To properly implement the pseudo-truncation theory (to correctly estimate the MOR and MOE distributions of graded subpopulations), one must know the...

This article details techno-economic analyses for producing alternative jet fuel (AJF) at a greenfield integrated biorefinery (IBR) using softwood forest residues. The scenarios and their corresponding economic outcomes differ based on the co-product selections. The selected technology to produce AJF uses a mild bisulfite pretreatment process to prepare the feedstock for enzymatic hydrolysis and fermentation to isobutanol, which is then upgraded to hydrocarbon ‘drop-in’ fuels using an alcohol-to-jet process. The hydrocarbons are a combination of jet fuel and aviation gasoline (AvGas). The...

The above-ground performance of decking treated with two alternative copper-based preservative formulations is being evaluated at a test site near Madison, Wisconsin, USA. Southern pine sapwood lumber specimens (38 mm by 140 mm by 910 mm) were pressure treated with 0,93 %, 1,40 % or 2,34 % (oxide basis) actives concentrations of a boron-copper formulation (BC) composed of 7,2 % copper hydroxide and 92,8 % sodium tetraborate decahydrate. Similar specimens were pressure-treated with 0,66 % or 1,32 % actives concentrations of a copper-zinc formulation (CZDP) composed of 18 % copper (CuO...

Machine lumber grading has been applied in commercial operations in North America since before 1963, and research has shown that machine grading can improve the efficient use of wood. However, industry had been reluctant to apply research findings without clear evidence that the change from visual to machine grading would be a profitable one. Since 2000, when the most recent version (FPL-GTR-7) of this report was published, new equipment, production scenarios, forest resource changes, and other issues have arisen, resulting in the need for another update. This new report provides key...

Summary of presentation given at the RTA annual meeting in 2019. The presentation discussed the use of born rods as a form of passive dual treatment for borate/creosote treated ties/timbers.