The essential oil components of cedar heartwoods play an important role in the durability of these trees. Yet, the composition of these oils and identity of many of the compounds remains unknown, or incompletely know for some commercially important cedar heartwoods. The essential oil extracts of Alaska Yellow Cedar (Chamaecyparis...
There is a continual interest in developing robust, flexible, durable, lightweight, waterborne polymer barrier coatings which are increasingly resistant towards both chemical warfare agents as well as an ever growing number of toxic industrial chemicals. In this study, barrier films were prepared with poly(vinyl alcohol) (PVOH) and varying amounts of...
Synthetic adhesives, such as phenol-formaldehyde (PF) resins and urea-formaldehyde (UF) resins, have dominated the wood adhesive market since they were introduced in the wood products industry. Formaldehyde, as a key component in the manufacturing of PF and UF resins, has been classified as a known human carcinogen by the International...
Agroforestry is a traditional farming practice in American Samoa that has helped to sustain the livelihood of the native population for centuries. These once self-sufficient islands have become economically dependent on U.S monies and other external resources during the past century. Dependency has caused a shift in the carrying capacity...
High density polyethylene (HDPE) is a ubiquitous material with versatile properties. It is produced and used in greater volume than any other thermoplastic. HDPE is often filled with a variety of materials for various applications. Glass fiber and wood flour are two common fillers for HDPE. Recently there has been...
Many herbivores of the Pacific Northwest rely on forest understory shrub leaves for a source of nitrogen, energy, and moisture. I measured nitrogen, protein-binding capacity, and condensed tannin concentration as indicators of available nitrogen; cell wall constituents and lignin as indicators of available energy; and moisture concentration in young and...
In undisturbed N-limited forested catchments, DON may represent over 90% of the total N lost in streams. Some ecologists have suggested that plant-derived reactive polyphenols may be responsible for DON binding and transport because polyphenol-protein complexes are known to precipitate out of solution, bind to mineral surfaces or organic matter...
Formaldehyde-based adhesives such as urea-formaldehyde (UF) and phenol-formaldehyde (PF) adhesives dominate the current wood adhesive market. However, these adhesives are derived from petrochemicals and carcinogenic formaldehyde. In this study, we developed two formaldehyde-free adhesives based on abundant, renewable, and inexpensive soy flour (SF).
The first adhesive was mainly composed of...
Large numbers of vintage reinforced concrete deck-girder bridges remain in the national bridge inventory. Many of these exhibit diagonal cracking and other distress. Due to the design practices of the time, it is common to observe cracks at locations where flexural reinforcing steel is terminated along the span. The presence...
Microchannel devices are rapidly evolving process technology with a wide variety of applications. Microchannel devices hold the potential to transform many separation processes. One potential application for such microchannel devices is kidney dialysis. By reducing the size and cost of the device, this technology offers the potential to allow dialysis...
This study examined the relationship of interfacial shear strength (IFSS) and
bending strength (MOR) of several different wood-plastic composites (WPC's).
Plastics utilized were high-density polyethylene (HDPE) and polypropylene (PP).
Pine and oak were used as the wood species. Compatibilizers used included maleicanhydride
polyethylene (MAPE), polymeric methylene diphenyl diisocyanate (PMDI),
KymeneTM,...
Spotted knapweed, Centaurea maculosa Lam. (Compositae) is an extremely
successful introduced weed species in the northwestern United States. Multiple factors
may be responsible for its success, including chemical defense. Two different types of
putative chemical defense agents are the focus of this thesis. The first is a bitter-tasting
sesquiterpene lactone,...
While the heartwood of many wood species exhibits excellent resistance to fungal and insect attack, this resistance is sometimes diminished in second-growth material of the same species. The reasons for the reduced durability are unclear, but they may reflect a combination of both higher proportions of sapwood as well as...
Copper migration from treated wood has created concerns within the
environmental community because of the potential effects of this heavy
metal on aquatic organisms. Migration can be limited, to some extent, by
more controlled treatments and by post-treatment processing, but these
actions cannot completely overcome the problem. An alternative approach...
This research provides details of water resource conflict and cooperation in Oregon between 1990 and 2004 by using an event database methodology. Events were concentrated in four of 18 basins. No basin accounted for more that 25% of the total water rights events, the most evenly distributed issue type. Overall...
