Treesearch

The use of mass timber structural products in tall building applications (6–20 stories) is becoming more common around the world including North America. A potential concern is the environmental wetting of mass timber products during construction because such products may dry out more slowly than light-frame structural lumber, and wood, as an organic material, is susceptible to deterioration at elevated moisture contents. In order to better understand the moisture conditions present in high rise timber constructions, a long-term moisture monitoring program was implemented on an eight...

A solvent-free route was developed to fabricate 100% biobased, renewable, and degradable polylactide (PLA) composites reinforced will ball-milled celluloses. The results show that the original pulp cellulose fibers were modified to partial amorphization through 30-min ball milling. Filling the ball-milled celluloses into PLA increased the tensile modulus for the resultant cellulose/PLA composite materials, while decreased their tensile strength and impact resistance. This method can be used to access the cost-efficient PLA-based composite materials with tunable mechanical properties. The...

This paper is a written summary of the keynote lecture presented at the 13th Annual Meeting of the Northern European Network on Wood Science and Engineering (WSE2017). The lecture summarized work performed at the Forest Products Laboratory (Madison, WI, USA) over the past 10 years related to understanding diffusion through cell walls. The highlighted work includes advances in electrical measurements and synchrotron-based X-ray fluorescence microscopy. The paper also discusses how diffusion is related to many wood damage mechanisms. The ultimate goal of the presented research is to develop...

Bridge inspection using a drone, also referred to as an unpiloted aircraft system, has gained more interest in recent years among bridge owners, researchers, and stakeholders because of its efficiency and effectiveness. In fact, numerous bridges classified as structurally deficient in the United States that require more attention and effort for maintenance activities can be inspected using drones in an efficient manner. The primary goal of this project was to evaluate drones as supplemental bridge inspection tools for bridges that present accessibility challenges for inspectors. To...

Lignin is a heterogenous plant cell wall polyphenol derived primarily from hydroxycinnamyl alcohols via combinatorial radical coupling reactions containing ether- and C-C linkages [2]. Its depolymerization is challenging, making lignin a major barrier to gaining access to stored energy within lignocellulosic materials [3]. Termites from the sub family Macrotermitinae form a monophyletic group of species that have cultivated fungi (Termitomyces spp.) using wood materials and are able to decompose lignocellulose almost completely [4]. Fungus-cultivating termites have evolved in mutualistic...

Dynamic vapor sorption (DVS) measurements are widely used to collect water vapor sorption isotherms for wood and other cellulosic materials. Equilibrium moisture content (EMC) is typically assumed to have been reached when the rate of change in moisture content with time (dM∕dt) drops below a certain value. However, the errors associated with determining EMC in this manner have never been characterized. Here, an operational defnition of equilibrium for DVS measurements is provided, and twenty test cases over four cellulosic materials are presented where the relative humidity was stepped up...

A post-esterifcation with a high degree of substitution (hDS) mechanical treatment (Pe(hDS)M) approach was used for the production of highly hydrophobic cellulose nanoparticles (CNPs). The process has the advantages of substantially reducing the mechanical energy input for the production of CNPs and avoiding CNP aggregation through drying or solvent exchange. A conventional esterifcation reaction was carried out using a mixture of acetic anhydride, acetic acid, and concentrated sulfuric acid, but at temperatures of 60–85 ◦C. The successful hDS esterifcation of bleached eucalyptus kraft...

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...