USDA Forest Products Laboratory Research Articles

Species, grading, and mechanical properties of locally sourced timber in the Joyabaj region of Guatemala

The purpose of this project was to research the timber used by Engineers without Borders (EWB) groups in the Joyabaj region of Guatemala. This project aimed to investigate the species of wood, evaluate the quality by assessing the distribution of timber grades, and determine mechanical properties. The results will aid EWB groups in the design of wood structures in the Joyabaj region of Guatemala.Samples were collected for species investigation and mechanical testing. Species investigation was triangulated from interviews with the sawmill owner, construction foreman, testing by the USDA Forest Products Laboratory, and comparisons to literature. The results were inconclusive and indicated multiple species were intermixed at the sawmill with no distinction made when purchased. Timber quality was evaluated by using a visual grading guide developed by the authors to assess the distribution of grades within a large order of lumber. Static bending and compression parallel to grain tests were conducted to obtain modulus of rupture, compression parallel to grain, and modulus of elasticity. Specific gravity was also obtained.The results indicate that three different species were collected. Ninety per cent (90%) of the timber was No. 3 or better and 50% to 80% was No. 2 or better depending on the size. Clear wood testing values were similar to those of Eastern White Pine. Structural design should be performed based on National Design Specification (NDS) design values for a No. 3 or No. 2 Eastern White Pine, depending on the degree of wood selection in the construction process.

Conversion Economics of Forest Biomaterials: Risk and Financial Analysis of CNC Manufacturing

AbstractCommercialization of cellulose nanocrystals (CNC) presents opportunities for a wide range of new products. Techno‐economic assessments can provide insightful information for the efficient design of conversion processes, drive cost‐saving efforts, and reduce financial risks. In this study, we conducted techno‐economic assessments for CNC production using information from the USDA Forest Products Laboratory Pilot Plant, literature, and discussions with experts. Scenarios considered included variations related to greenfield, co‐location, and acid recovery. Operating costs, capital investment, minimum product selling price (MPSP), financial performance metrics, and the effect of drying and higher reaction yields on CNC manufacturing financials were estimated for each scenario. The lowest MPSP was found for the co‐location without acid recovery scenario, mainly driven by capital investment. Risk analysis indicates 95% probability of manufacturing costs lower than USD 5900/t of CNC (dry equivalent) and a MPSP lower than USD 7200/t of CNC (dry equivalent). Finally, based on our analysis, we provide guidance on process optimizations that can improve the economic performance of CNC manufacturing process. In addition, a risk profile of the CNC manufacturing business is provided. © 2017 Society of Chemical Industry and John Wiley & Sons, Ltd

Rate of convergence of k-step Newton estimators to efficient likelihood estimators

We make use of Cramér conditions together with the well-known local quadratic convergence of Newton's method to establish the asymptotic closeness of k-step Newton estimators to efficient likelihood estimators. In Verrill and Johnson [2007. Confidence bounds and hypothesis tests for normal distribution coefficients of variation. USDA Forest Products Laboratory Research Paper FPL-RP-638], we use this result to establish that estimators based on Newton steps from n -consistent estimators may be used in place of efficient solutions of the likelihood equations in likelihood ratio, Wald, and Rao tests. Taking a quadratic mean differentiability approach rather than our Cramér condition approach, Lehmann and Romano [2005. Testing Statistical Hypotheses, third ed. Springer, New York] have outlined proofs of similar results. However, their Newton step estimator results actually rely on unstated assumptions about Cramér conditions. Here we make our Cramér condition assumptions and their use explicit.

Erratum: Genome sequence of the lignocellulose degrading fungus Phanerochaete chrysosporium strain RP78

Nat. Biotechnol. 22, 695–700 (2004) The credit on the contents page for the cover image of the June issue read “Photo courtesy of T. Kuster (USDA Forest Products Laboratory, Madison, WI).” The credit should have included L. Hornick (US DoE Joint Genome Institute, Walnut Creek, CA).

An evaluation of two acid Hydrolysis processes for the conversion of cellulosic feedstocks to Ethanol and other chemicals

The Tennessee Valley Authority (TVA) has been actively involved in the development of acid hydrolysis processes for the conversion of cellulosic feedstocks to ethanol since 1981. At that time, the TVA renewed earlier work conducted in the 1950s with the USDA Forest Products Laboratory to develop a dilute sulfuric acid hydrolysis process. Hydrolysis research at the TVA was further expanded in 1983 with the development of a concentrated sulfuric acid hyrolysis process for converting cellulosic feedstocks to sugars for ethanol production. Both processes are being developed in laboratory-, bench-, and pilot-scale studies. Ethanol yields from the two processes are 63 gal/t using dilute acid hydrolysis and 72 gal/t using the concentrated acid hydrolysis. An economic assessment of the two processes has been conducted using a base-case, commercial-scale design for producing 11M gal/yr of ethanol. Hardwoods and corn stover are used as feedstocks for the dilute and concentrated sulfuric acid hydrolysis processes, respectively. This paper will evaluate the effects of both internal and external factors on ethanol production costs. The sensitivity of these costs to technology, market, and economic changes will be presented.

Silicon-29 NMR aids study of lignins

Silicon nuclear magnetic resonance spectra of silylated lignins offer numerous advantages for studying the complex wood polymers, says chemist John Ralph of the Department of Agriculture's dairy forage research center in Madison, Wis. Compared with carbon-13 NMR, silicon-29 spectra offer greater sensitivity and can be obtained faster, he says. Ralph presented his research at a symposium on NMR characterization of plant cell wall polymers that focused primarily on lignin. Although organic chemists have been studying lignin for decades, its structure is so complex and varies so much from tree to tree that many details remain to be filled in, says Lawrence L. Landucci, a chemist with USDA's forest products laboratory in Madison, who was one of the symposium organizers. The fastpaced development of new NMR techniques in the past decade has prompted lignin chemists to reinvestigate the technique. Lignin contains numerous phenolic, primary, and secondary hydroxyl groups that can form silyl ethers, Ralph points ...

Light-Frame Construction Research at USDA Forest Products Laboratory — A Status Report

USDA Forest Products Laboratory research aimed at improved performance of structural components and more effective use of wood for light-frame construction is described. In addition, dissemination of research results through in-house publications and technology transfer is discussed.