Treesearch

Pyrolysis of wood is a series of chemical and physical changes that occur simultaneously. Previous investigations of pyrolysis have often simplified the process. For wood building materials, the pyrolysis process is typically simplified to the formation of “char” at 300°C. Pyrolysis models are often simplified by using the thermal degradation of isolates reference polymers in an inert atmosphere. This approach assumes that the structure of bulk wood performs similarly to that of the isolated polymers being used and ignores reactions with oxygen. This dissertation explores the molecular-scal...

Wood deterioration, due to decay fungi, shortens the useful life span of wood and wood-based materials. Prescriptive preservative treatment is the most effective way to reduce the detrimental effects of these persistent microorganisms, particularly in soil contact and areas of critical use. A thorough understanding of decay hazard in soil contact is critical for proper selection and use of wood in ground contact. Current AWPA guidelines in the Use Category System specify 5 zones of severity regarding wood decay fungal hazard but contain very little information on diversity and abundance of...

Tungsten carbide (WC) nanostructures were prepared by carbothermal reduction (CR) of tungsten-impregnated pinewood-derived activated carbon (AC) at 1000 ◦C under an inert atmosphere. Brunauer–Emmet–Teller (BET) surface area, pore structures of the AC, and catalyst samples were evaluated by N2 adsorption–desorption experiments. The structures of the catalysts were characterized using X-ray powder diffraction (XRD). The morphologies and particle structures of the synthesized WC nanoparticles were investigated by field emission scanning electron microscopy (FESEM) and high-resolution transmiss...

One rate-limiting factor in the fight against illegal logging is the lack of powerful, affordable, scalable wood identification tools for field screening. Computer vision wood identification using smartphones fitted with customized imaging peripherals offers a potential solution, but to date, such peripherals suffer from one or more weaknesses: low image quality, lack of lighting control, uncontrolled magnification, unknown distortion, and spherical aberration, and/or no accessto or publication of the system design. To address cost, optical concerns, and open access to designs and parameter...

Kraft lignin was catalytically graphitized to graphene-based nanostructures at high temperature under non-oxidative atmospheres. To obtain the best catalytic performance, a uniform catalyst–lignin mixture must be made by bonding transitional metal (M) ions to oxygen (O), sulfur (S) or nitrogen (N)-containing functional groups in kraft lignin. One of the strategies is to dissolve or disperse kraft lignin in a suitable solvent, whereby the polymer chains in the condensed lignin molecules will be detangled and stretched out while the functional groups are solvated, and when mixing lignin...

Canola is widely grown in the northern latitudes for its vegetable oil, generating large quantities of residual, low value canola flour used as animal feed. The common wood adhesive poly(diphenylmethylene diisocyanate) (pMDI) should react with the wide variety of functional groups in proteins. Therefore, it would seem that canola flour with added pMDI could be an effective adhesive. Two main questions are addressed in this study: How do the wood adhesive properties of canola flour compare to the better-studied soy flour? How well do proteins, which contain an abundance of functional...

Mass timber building materials such as cross-laminated timber (CLT) have captured attention in mid- to high-rise building designs because of their potential environmental benefits. The recently updated multistory building code also enables greater utilization of these wood building materials. The cost-effectiveness of mass timber buildings is also undergoing substantial analysis. Given the relatively new presence of CLT in United States, high front-end construction costs are expected. This study presents the life-cycle cost (LCC) for a 12-story, 8,360-m2 mass timber building to be built in...

Researchers have developed various methods and tools for nondestructively testing urban trees for decay and stability. A general review of these methods includes simple visual inspection, acoustic measuring devices, microdrills, pull testing, ground penetrating radar, x-ray scanning, remote sensing, electrical resistivity tomography and infra-red thermography. Along with these testing methods have come support literature to interpret the data.

Cellulose nanocrystals (CNCs) derived from renewable plant-based materials exhibit strong potential for improving properties of polymers by their dispersal in the polymer matrix as a composite phase. However, the hydrophilicity and low thermal stability of CNCs lead to compromised particle dispersibility in common polymers and limit the processing conditions of polymer−CNC composites, respectively. One route that has been explored is the modification of CNCs to alter surface chemistry. Acrylic materials are used in a broad class of polymers and copolymers with wide commercial applications....

Plastic wastes pose a serious threat to the environment and there has been strong interest in developing soy protein isolate (SPI)-based plastics to reduce the use of traditional petroleum-based ones. However, the use of SPI plastics has been hindered due to their inferior mechanical properties and poor water resistance compared with traditional plastics. In this work, SPI plastics with significantly improved mechanical properties and water resistance were developed using UV-curable SPI resin and UV-curable cellulose nanofibers. Three UV-curable materials, i.e., methacrylated SPI (MSPI),...