Treesearch

Seismic force resisting systems based on cross-laminated timber (CLT) shear walls have garnered considerable attention for in mid-rise construction around the world. The purpose of this study was to determine seismic performance factors for CLT shear wall systems in platform type construction. These factors, namely, the response modification factors, R, overstrength factor, Ωo and deflection amplification factor, Cd, have been developed in this study for CLT walls and proposed for inclusion in ASCE 7. The study follows the FEMA P695 methodology that incorporates testing, evaluating a...

Improving productivity and lipid concentration in microalgae is important for the economic success of both biofuel and microalgae coproducts production. Nannochloropsis spp. are marine microalgae currently being grown at large-scale for the production of biofuel and lipid coproducts. Here we demonstrate improvements of growth and omega-3 production in Nannochloropsis gaditana CCMP526 and Nannochloropsis oceanica CCAP849/10 with plant substrate addition, a potentially economical option for increasing microalgal productivity. We examine growth in the presence of corn stover, switchgrass,...

In July, the resiliency of the U.S. housing market was a bright spot for the aggregate U.S. economy. Most month-over-month sectors were positive, and the majority of year-over-year categories were positive as well. Year-over-year, total multifamily permits, single-family housing under construction, single-family completions, and single-family construction spending indicated declines.

During adaptive metabolic evolution a native glycerol dehydrogenase (GDH) acquired a D-lactate dehydrogenase (LDH) activity. Two active-site amino acid changes were detected in the altered protein. Biochemical studies along with comparative structure analysis using an X-ray crystallographic structure model of the protein with the two different amino acids allowed prediction of pyruvate binding into the active site. We propose that the F245S alteration increased the capacity of the glycerol binding site and facilitated hydrogen bonding between the S245 γ-O and the C1 carboxylate of pyruvate....

This study was focused on measuring the properties of twenty-three commercially available coatings formulated for exterior wood applications. The coatings were characterized by measuring their surface tension, solid content, viscosity, pH, and glass transition temperatures (Tg). Additionally, the wetting properties of coating droplets on wood substrates were measured. The contact angle of solvent-based and water-based coatings were characterized on untreated southern yellow pine wood samples using high-resolution image analysis and the Young–Laplace solution. An innovative image processing...

Arabinofuranose substitutions on xylan are known to interfere with enzymatic hydrolysis of this primary hemicellulose. In this work, two novel α-L-arabinofuranosidases (ABFs), TtABF51A from Thielavia terrestris and EpABF62C from Eupenicillium parvum, were characterized and functionally analyzed. From sequences analyses, TtABF51A and EpABF62C belong to glycoside hydrolase (GH) families 51 and 62, respectively. Recombinant TtABF51A showed high activity on 4-nitrophenyl-α-Larabinofuranoside (83.39 U/mg), low-viscosity wheat arabinoxylan (WAX, 39.66 U/mg), high-viscosity rye arabinoxylan (RAX,...

Acetylation is widely used as a wood modifcation process that protects wood from fungal decay. The mechanisms by which acetylation protects wood are not fully understood. With these experiments, we expand upon the literature and test whether previously observed differences in iron uptake by wood were a result of decreased iron binding capacity or slower diffusion. We measured the concentration of iron in 2 mm thick wood sections at 0, 10, and 20% acetylation as a function of time after exposure to iron solutions. The iron was introduced either strongly chelated with oxalate or weakly...

Global demand for renewable and sustainable materials such as wood products is growing. To support this growth, a scientific approach is necessary to illustrate the environmental benefits of wood products. This report contains a detailed cradle-to-gate life-cycle assessment method including data collection, development of life-cycle inventory, and life-cycle impact assessment for production of redwood lumber in the United States. The results illustrated that redwood lumber production has a very low carbon footprint (37.97 kg CO2e/m3 of lumber) and stores about 18 times more carbon compared...

A thorough understanding of microbial communities in the gut of lower termites is needed to develop target-specifc and environmentally benign wood protection systems. In this study, the bacterial community from Reticulitermes virginicus was examined by Illumina sequencing of 16S ribosomal RNA (rRNA) spanning the V3 and V4 regions. Prior to library preparation, the termites were subjected to fve treatments over an 18-day period: three groups were fed on wood treated with 0.5% chitosan, 25% acetic acid, or water, the fourth group was taken directly from the original collection log, and the...

This study reports on acomparative study of acid hydrotropic fractionation (AHF) of birch wood using maleic acid (MA) and p-toluenesulfonicacid (p-TsOH). Under the same level of delignification, lignin dissolved by MA is much less condensed with ahigher content of ether aryl b-O-4 linkages. Lignin depolymerization dominated in MA hydrotropic fractionation (MAHF) and resulted in asinglelower molecular weightpeak, in contrast to the competitive depolymerizationand repolymerization in p-TsOH AHF with abimodal distribution. The less condensed MA-dissolved lignin facilitated catalytic conversion...