Treesearch

This report summarizes information on condition assessment of in-service wood, including visual inspection of wood and timbers, use of ultrasound and probing/boring techniques for inspection, and assessment of wood and timbers that have been exposed to fire. The report also includes information on assigning allowable design values for in-service wood.

Cellulose is the most abundant naturally occurring polysaccharide. Its inherent mechanical stability, biocompatibility, biodegradability, and abundant hydroxyl groups available for derivatization provide benefits in the production of fiber-based materials such as conductive fibers. Cellulose derivatives, including cellulose esters such as cellulose acetate (CA), are readily generated in the fiber form following dissolution using a variety of solvents. Electrospinning is one of the emerging technologies with an outstanding ability to regenerate fibers in the nanoscale range. Polyaniline...

As CO2 emissions reach record highs, finding renewable, low-cost, and low-carbon alternatives to fossil fuel-based products is critical. This study examines the techno-economic and life cycle assessment (TEA-LCA) of lignin-based blended resin for 3D printing, investigating lignin, a renewable and affordable resource, as an alternative to petroleum-derived resins. Kraft lignin was fractionated into a low molecular weight fraction and combined with commercial resin in a 9:1 ratio or 10 % by weight. TEA estimated the production cost of the resin at $38.43/kg with a minimum selling price of...

Three-dimensional (3D) printing has emerged as a transformative technology in the construction sector; however, cementitious composites are hindered by high costs and substantial environmental impacts. This study investigates cellulose nanocrystals (CNC)-reinforced cementitious mixture for its economic feasibility and environmental impacts in the 3D printing sector. In this study, a commercial large-scale process model with a daily capacity of 100 m3 for cementitious mixture production for 3D printing was developed. The estimated minimum selling price (MSP) of CNC-reinforced cementitious...

Knowledge of wood property variation within trees is critical for understanding age effects on wood formation and for improved utilization of forests, and maps provide an effective way to efficiently summarize and visually represent variability. Despite the importance of maps, examples for North American conifers are rare. Most studies focus on plantation grown trees, with the majority examining loblolly and radiata pine. For these species almost all maps can be categorized into two groups related to tracheid differentiation processes. One group includes properties related to secondary...

Audible sound is known to originate from wildland fires. We show audible sound is accompanied by infrasound emissions, originating from the active combustion zone in a prescribed fire. We collected data from one of multiple prescribed burns conducted at Eglin Airforce Base, Florida in March of 2023. Single-unit infrasonic sensors and a six-element array were deployed outside the burn unit to capture acoustic signals. The array was configured as a hexagon with aperture of ~10 m. Dual-band radiometers were deployed inside the unit to track the fire’s evolution. A broadband signal is observed...

Distribution shift, a phenomenon in machine learning characterized by a change in input data distribution between training and testing, can reduce the predictive accuracy of deep learning models. As operator and hardware conditions at the time of training are not always consistent with those after deployment, computer vision wood identification (CVWID) models are potentially susceptible to the negative impacts of distribution shift in the field. To maximize the robustness of CVWID models, it is critical to evaluate the influence of distribution shifts on model performance. In this study, a...

Hardwood porosity domains (diffuse-, semi-ring-, and ring-porosity) exist along a spectrum with some taxa embodying only one porosity domain and others spanning more than one. A cascading model scheme involving a root-level porosity classifier and second-level taxonomical classifiers might be useful for mitigating reductions in the predictive accuracy of North American computer vision wood identification (CVWID) models when the number of classes increases. Thus far, the porosity classifier has been trained on images covering the breadth of the porosity spectrum. By reducing ambiguity near...

The USDA Forest Service, Forest Products Laboratory, was asked to inspect the timber frame that supports the USS Cairo, a historic civil war ship at the Vicksburg National Military Park in Vicksburg, Mississippi. Because the display of the historic ship and its support structure are located outdoors and are exposed to the elements, there is concern about deterioration from decay of the support structure. This report summarizes the results obtained from the inspection and assessment. It includes a summary of observations, wood species identification, and recommendations. The timber support...

Lignin possesses diverse bioactivities due to its unique physicochemical structure. This study investigates the structural-bioactivity relationships of lignin derived from maleic acid hydrotropic fractionation (MAHF) of two types of herbaceous biomass. The results indicated that lignin with higher phenolic hydroxyl (-OH) content (up to 2.0 mmol/g) and carboxyl (-COOH) groups (up to 0.89 mmol/g) exhibited significantly enhanced antioxidant activity. The highest antioxidant of MAHF lignin (MAHL) reached 98 % for scavenging DPPH (2,2-diphenyl-1-(2,4,6-trinitrophenyl)hydrazyl) at 0.56 mg/mL....