Treesearch

This fully bilingual revised and expanded edition of the 2011 publication, Identification of Central American Woods, will serve as a field manual for the identification of the common commercial timbers of Central America, Mexico, and the Caribbean. It is intended as a tool for customs inspectors and other officials to control and regulate the flow of timber and wood products into and out of their countries and can be used as an academic reference to train wood anatomists.

Nickel (Ni)-lignin nanocomposites were synthesized from nickel nitrate and kraft lignin then catalytically graphitized to few-layer graphene-encapsulated nickel nanoparticles (Ni@G). Ni@G nanoparticles were used for catalytic decomposition of methane (CDM) to produce COx-free hydrogen and graphene nanoplatelets. Ni@G showed high catalytic activity for methane decomposition at temperatures of 800 to 900 °C and exhibited long-term stability of 600 min time-on-stream (TOS) without apparent deactivation. The catalytic stability may be attributed to the nickel dispersion in the Ni@G sample....

In this work, few-layer graphene materials were produced from Fe-lignin nanocomposites through a molecular cracking and welding (MCW) method. MCW process is a low-cost, scalable technique to fabricate few-layer graphene materials. It involves preparing metal (M)-lignin nanocomposites from kraft lignin and a transition metal catalyst, pretreating the M-lignin composites, and forming of the graphene-encapsulated metal structures by catalytic graphitization the M-lignin composites. Then, these graphene-encapsulated metal structures are opened by the molecule cracking reagents. The graphene...

Layers of cellulose nanofibers (CNF) have great potential to be used in food packaging applications because of their oxygen and grease barrier properties. However, because of their sensitivity to moisture, they likely will need to be used in a layered structure with water vapor barrier layers. Waterborne barrier coatings (WBBC) have the potential to provide this water vapor barrier, but their performance on paper with a CNF layer has not been described in the literature. Paper that had a CNF layer was coated with three different WBBC with various levels of two different barrier pigments to...

The brown rot fungus Fomitopsis pinicola efficiently depolymerizes wood cellulose via the combined activities of oxidative and hydrolytic enzymes. Mass spectrometric analyses of culture filtrates identified specific proteins, many of which were differentially regulated in response to substrate composition.

Knowledge of local mechanical behaviour of wood is especially important as silvicultural practices are modified to allow wood to compete as a relevant material in high technology applications. Challenges associated with identification of local mechanical behaviour have resulted in simplified test geometries designed to determine one or two constitutive parameters. The objective of this work was to design and simulate an entire experiment developed to simultaneously identify the earlywood and latewood orthotropic stiffnesses in loblolly pine in a single specimen and load geometry. The...

To better reserve food from the interaction with oxygen, moisture, and (light) ultraviolet (UV) radiation, typical polymer film packaging is produced as opaque or metalized sheets. There is increasing consumer demand for multifunctional transparent packaging or a transparent window to allow viewing of food before consumer purchase. Cellulose nanocrystals (CNCs), as a type of sustainable and biodegradable material, show great potential for transparent food packaging by providing good oxygen permeation resistance. However, CNCs are poor in preventing UV light transmission, sensitive to...

Paper based packaging has the potential to replace many plastic-based systems if the required barrier properties can be obtained. Water borne barrier coatings have the potential to generate good barrier layers, but their performance is often less than expected. Recent work has shown improved performance of these coatings when applied on paper that has a cellulose nanofiber layer. Here, papers with a cellulose nanofiber layer were coated with barrier coatings at different coat weights applied as single-layers, as double-layers, and single-layers pressed together in a hot press in order to...

The effect of foam discontinuity in the shear zone of structural insulated panel (SIP) beams was investigated in the current research. Two depths of 15.24 cm and 31.11 cm (6.5 in. and 12.25 in.) SIPs were evaluated in 1/3-point bending. Panels were sawn into beams, each approximately 29.84 cm (11.75 in.) wide, for the mechanical testing. Half of the panels had joints or discontinuities in the foam layer in a location that was subject to shear stress during the bending tests. Half of the panels did not have joints or discontinuities in the foam layer in the locations that were subject to...

The utility sector has been employing ultrasonic-based nondestructive evaluation (NDE) to determine the cross-sectional groundline integrity of wooden utility poles. While it is far less invasive than other methods, its efficacy has not been thoroughly studied. This study aims to fill this technical gap by analyzing the correlation between the propagational characteristics of the ultrasonic stress wave using a novel embedded waveguide technique and the existing destructive testing methods. The proposed embedded waveguide technique excites diffusive Rayleigh mode (AW2) propagating in the...