Treesearch

Utility pole failures are a known cause of wildland fires. Over the past 15 years in the U.S. Department of Interior, Bureau of Land Management (BLM) Idaho Boise District, 299 wildland fires have been related to electric utility powerline structure failures, an average of 20 wildland fires per year. Routine inspection and maintenance would likely reduce the number of wildland fires caused by utility pole failures. The sheer number of poles and the great distances over which electrical lines span in the BLM Idaho Boise District are factors that complicate regular inspections. BLM recognizes...

Bark beetles and root weevils can impact forests through tree death on landscape scales. Recently, subterranean termites have been linked to these beetles via the presence of bluestain fungi (Ascomycota: Ophiostomataceae), which are vectored to trees by beetles. However, only a small subset of bluestain species have been examined. Here, we tested whether termite-bluestain association patterns in the field reflect termite feeding preference in laboratory choice trials. We documented the presence of four bluestain fungi (Leptographium procerum (W.B. Kendr.), L. terebrantis (Barras & Perry),...

As one of the most abundant and versatile natural materials on Earth, recently wood has attracted tremendous attention from scientists and engineers due to its outstanding advantages, including hierarchically porous microstructure, high mechanical strength, environmental friendliness, renewability, and biodegradability. Wood’s hierarchically porous structure and chemical components (e.g., cellulose, hemicelluloses, and lignin) enable its mechanical, ionic, optical, and thermal properties to be tuned via physical, chemical, and/or thermal modifications. Among these various approaches, the...

In cellulose materials, the cellulose II allomorph is often present either exclusively or in conjunction with cellulose I, the natural cellulose. Moreover, in regenerated and mercerized fibers (e,g., lyocell and viscose), natural cellulose adopts to the crystal structure cellulose II. Therefore, its detection and quantitation are important for a complete assessment of such materials investigations. In the Raman spectra of such materials, a band at 577 cm -1 is typically observed indicating the presence of this allomorph. In the present study, to quantify the content of cellulose II, a...

Colloidal lignin nanoparticles (LNPs) from low temperature acid hydrotropic fractionation (AHF) of poplar wood and commercial alkali lignin using p-Toluenesulfonic acid (p-TsOH) were directly mixed with PVA to make PVA/AHF-LNP nanocomposite films. p-TsOH itself acted as a plasticizer for PVA; however the application of p-TsOH alone reduced PVA film tensile strength and therefore toughness. At proper loadings of LNPs and p-TsOH, both the failure strain and tensile strength of PVA/AHF-LNP composites were improved. The formation of hydrogen bonding between the p-TsOH/AHF-LNP aggregates with...

Development of a novel and efficient inverse method for anisotropic material identification based on a complex-variable formulation of Airy stress function is presented. The overall equilibrium and compatibility, as well as the free traction along the boundary of the internal geometric cutouts, are analytically satisfied by means of conformal mapping and analytic continuation. The inverse problem is posed as an optimization problem where the objective functional is the difference between the measured data and its counterpart evaluated using the complex-variable method. Validity of the...

This paper highlights research results from a joint effort between the Forest Products Laboratory (FPL) in the United States of America (USA) and the University of Coimbra (UC) in Portugal (PT). The main objective is the development of a Timber-Concrete Composite system (TCC) that utilizes precast concrete deck panels that accelerate construction times and can easily be removed to facilitate bridge repair/rehabilitation efforts and reuse options. The research is focused on various critical aspects such as the type of interconnection between the concrete deck and the glued laminated timber...

This paper presents a framework to better identify and measure defects in a bridge using drone-based inspection images integrated with grayscale image enhancement techniques. For this study, a DJI Matrice 210 drone was used for the inspection of a three-span timber bridge with concrete decking located in Keystone, South Dakota. During the inspection, the drone recorded a series of videos of the bridge using the MOVie (MOV, video file extension) video format. MOV-based image analysis was conducted to identify a variety of defect types (i.e., efflorescence, water leakage, spalling, and...

The Equivalent Lateral Force (ELF) procedure is the most widely used seismic analysis approach, because of its simplicity and practicality in preliminary and final design phases. This paper applies the ELF procedure to a hypothetical building that stands 5 stories tall, with a 4-story superstructure supported on a rocking story of elliptically profiled cross-laminated timber (CLT) walls. First-generation prototypes made from six CLT panels of 5-ply, 175 mm, thickness—each measuring 2.44 m by 3.66 m in respective width and height—demonstrated that elliptical geometry controls lateral...

During the summer of 2019, seven stress-laminated deck timber bridges were evaluated to assess their field performance and serviceability. These bridges were originally constructed during a six year period (1988-1994) using hardwood lumber as part of a national program initiative in the USA. Its aim was to increase the use of wood in transportation structures primarily in the rural regions of the country. To assess bridge performance, comprehensive visual inspections were conducted and advanced inspection tools were utilized to accurately assess the bridge superstructure components using a...