Treesearch

Background: The current state-of-the-art for feld wood identifcation to combat illegal logging relies on experienced practitioners using hand lenses, specialized identifcation keys, atlases of woods, and feld manuals. Accumulation of this expertise is time-consuming and access to training is relatively rare compared to the international demand for feld wood identifcation. A reliable, consistent and cost efective feld screening method is necessary for efective global scale enforcement of international treaties such as the Convention on the International Trade in Endagered Species (CITES) or...

The use of Unmanned Aerial Systems (UASs), commonly known as drones, has significantly increased over recent years in the field of civil engineering. In detail, the need for a more efficient alternative for bridge inspection has risen because of the increased interest from bridge owners. The primary goal of this paper is to evaluate the efficiency of a drone as a supplemental bridge inspection tool. To complete this study, a glued laminated (glulam) girder with a composite concrete deck bridge was chosen in South Dakota, and a Dà-Jiāng Innovations (DJI) Phantom 4 drone, was employed to...

The field of Civil Engineering has lately gained increasing interest in Unmanned Aerial Vehicles (UAV), commonly referred to as drones. Due to an increase of deteriorating bridges according to the report released by the American Society of Civil Engineers (ASCE), a more efficient and cost-effective alternative for bridge inspection is required. The goal of this paper was to analyze the effectiveness of drones as supplemental bridge inspection tools. In pursuit of this goal, the selected bridge for inspection was a three-span gluedlaminated timber girder with a composite concrete deck...

Unmanned aerial vehicle (UAV)-enabled bridge inspection has gained more interest over recent years among bridge owners, researchers, and stakeholders due to inefficiency and high cost of conventional access inspection techniques. A large number of deteriorating bridges can be efficiently inspected using UAVs equipped with various sensors. In fact, some departments of transportation (DOTs) (e.g., Minnesota DOT) in cooperation with research institutions have investigated the effectiveness of UAVs as a cost-efficient bridge inspection alternative. Based on the findings from the projects done...

This paper focuses on evaluating the effectiveness of an unmanned aerial vehicle (UAV) as a supplementary bridge damage quan-tification tool. For this study, a glued-laminated timber arch bridge in South Dakota was selected, and an UAV was utilized for the bridge dam-age quantification. A recommended four-stage UAV-enabled bridge damage quantification protocol involving image quality assessment and image-based damage quantification was developed. A field application using the UAV to measure crack lengths, thicknesses, and rust stain areas of the selected bridge was conducted following the...

This paper is intended to provide the state-of-the-art and of-the-practice on visual inspection, monitoring, and analysis of infra-structure using unmanned aerial vehicles (UAVs). Several researchers have inspected various civil infrastructures, including bridges, build-ings, and other structures, by capturing close-up images or recording videos, while operating UAVs. Various image analysis tools, such as the algorithm Morphological Link for Crack (Morpholink-C), were able to conduct precise measurements of crack thickness and length. Corrosion has also been detected using texture and...

Mass timber is a category of framing components that can be built with a variety of materials. Engineered wood products have become the backbone of the mass timber movement. Some of the most common mass timber structural elements used in buildings are glue-laminated beams (glulam), laminated veneer lumber (LVL) and cross laminated timber (CLT). However, wood is a natural material which is susceptible to decay and termite attack. Subterranean termites cause billions of dollars in damage each year and their primary food is wood. In the past few years, there has been an effort to expand the...

The paper industry produces a large volume of paper sludge as a byproduct of the paper making process. This results in a substantial environmental burden to the industry from the high levels of heavy metals contained in the sludge and can limit land management applications. Biochar may have the potential to reduce environmental impacts of paper sludge by immobilizing heavy metals in soil. In this study, modified rice straw biochars were produced using a gradient of heat treatments and potassium permanganate activation levels. The physiochemical and morphological properties of the produced...

A new method is described for producing high-lignin-containing and lignin-free cellulose nanocrystals from poplar wood (HLCNCs and LFCNCs, respectively). This was accomplished by first hydrothermally treating the poplar wood fibers at 170°C for 45 min in a Parr reactor. For obtaining HLCNCs, the treated fibers were directly hydrolyzed by 64% sulfuric acid whereas for LFCNCs, the fibers were delignified prior to the acid hydrolysis. The CNCs thus produced were characterized using spectroscopy, microscopy, and diffraction techniques and compared with bleached kraft pulp-CNCs. The comparison...

White pine (Pinus strobus) is commonly found in naturally regenerated even-aged stands on former agricultural lands throughout its range. These stands can be managed for rapid production of high-quality sawtimber, and are thus a valuable timber resource. Yet, periodic growth decline and mortality events have occurred, such as that observed in the late 1990s in southern Maine, USA. The present study uses increment measurements from white pine tree cores collected in the early 2000s to compare increment chronologies in high- and low-mortality stands in southern Maine. Periods and severity of...