Treesearch

Loblolly pine (Pinus taeda L.) is increasingly grown on intensively managed plantations that yield high growth rates. Wood properties, including specifc gravity (SG), change with cambial age, and thus intensively managed trees contain a high proportion of low density corewood when harvested because of reduced rotation lengths. This study was undertaken to develop models of ring-level properties (SG and width) in intensively managed loblolly pine plantations. Ninety-three trees from fve stands aged from 24 to 33 years were harvested, and 490 disks were obtained from in between the 5.2-m...

This article presents a new apparatus for collecting water vapor sorption isotherms in parallel with example data from acetylated and thermally modified loblolly pine. The experimental setup consists of an enclosure that is continuously flushed with a carrier gas of known RH supplied by an RH generator and a balance with precision of 0.1 mg. All samples are placed on the balance and the mass is monitored as a function of time. At a given RH, the measurements are stopped when the change in the total mass of all samples are less than or equal to a change in MC of 0.1 μg g-
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The apparent thermal conductivity of several insulation materials was measured over a range of temper- atures. A newly developed multilayer reflective insulation system called Mirrorpanel was tested against existing products. Mirrorpanel samples were prepared using layers of aluminum foil (emissivity of 0.11) and coated paper (emissivity of 0.52) separated by air spaces of approximately 5 mm, with fiberboard structural spacers. Steady-state heat flux was measured in the laboratory for 500 mm ×500 mm samples including several Mirrorpanel configurations as well as expanded polystyrene and...

Activated carbon (AC) developed and marketed for water and gas purification is traditionally made from hard coals (fossil-based materials). However, increasing awareness of environmental impacts caused by fossil fuel consumption and fossil-based products has provided a market opportunity for renewable and low-impact biobased products as alternatives including AC. The huge volumes of woody biomass generated from forest management activities could be used as feedstocks for these new bioproducts. These new bioproducts require evaluation to determine if they are low impact. To aid in quantifyin...

The fracture properties and toughening mechanisms of cellulose- and cellulose-rubber hybrid-modified epoxy polymers and glass-fibre (GF) composites are investigated. The cellulose modifiers used are microcrystalline cellulose (MCC) and cellulose nanocrystals (CNC), and the rubber modifiers are carboxyl-terminated butadiene-acrylonitrile (CTBN) and core-shell rubber (CSR). The toughening mechanisms of the MCC-epoxy and CNC-epoxy were identified to be crack deflection, shear band yielding, particle rupture or pull-out and debonding of the cellulose particles, which was followed by plastic...

This study systematically evaluated the influence of masterbatch preparation techniques, solvent casting and spin-coating methods, on composite properties. Composites were manufactured by combining CNCs masterbatches and PLA resin using twin screw extruder followed by injection molding. Different microscopy techniques were used to investigate the dispersion of CNCs in masterbatches and composites. Thermal, thermomechanical, and mechanical properties of composites were evaluated. Scanning electron microscopy (SEM) images showed superior dispersion of CNCs in spin-coated masterbatches...

Applications of cellulose nanomaterials (CNMs) have attracted increasing attention in recent years. One conceivable path lies in their commercial applications for packaging, in which their barrier properties will play an important role in determining their competiveness with conventional materials. This review critically analyzes the performance of CNMs acting as a barrier against moisture and oxygen permeation in CNM films, CNM-coated polymers and papers, and CNM-reinforced polymer composites, gives some insights into remaining challenges, and brings an overall perspective of compositing...

Coir is a natural, lignin rich, fber that can be found between the hard internal shell and the outer coat of a coconut. There are multiple products made from coir fbers but a signifcant amount of fbers accumulating from coconut processing remains unutilized. Coir fbers obtained from ripe (brown fbers) and unripe (white fbers) have a high lignin content about 41–42 wt%, a low ash content < 15 wt% and a high heating value of about 18.5–19 mj kg−1. The pelletizing properties were studied in a laboratory scale, single pellet press, and produced pellets were of high mechanical properties....

Mass timber structures have the potential to change wooden construction on a global scale. Numerous mass timber high-rise buildings are in planning, under development or already built and their performance will alter how architects and engineers view wood as a material. To date, the discussion of material durability and biodegradation in these structures has been limited. While all materials can be degraded by wetting, the potential for biodegradation of wood in a mass timber building requires special consideration. Identifying and eliminating the conditions that might lead to this...

Wooden bridges, such as historic covered bridges or modern railroad and highway bridges, can become susceptible to subterranean termite feeding. This can result in weakened structural integrity of the wooden members of these bridges, and possibly even structural failure if damage is not discovered early and control measures are not implemented. The goal of this study was to evaluate the use of various remote detection methods, including acoustic emission sound waves, interruption of light transmission, radar and microwave transmission, moisture monitoring, and changes in gas concentrations...