Eucalyptus Amplifolia and Corymbia Torelliana in the Southeastern USA: Genetic Improvement and Potential Uses

Eucalyptus amplifolia and Corymbia torelliana genetic improvement has been conducted in the lower southeastern USA by UF and collaborators since 1980. The collective accomplishments in genetic resources and potential commercial uses are summarized. For example, fast-growing, freeze-resilient E. amplifolia seeds are provided by 1st and 2nd generation seedling seed orchards (SSO) and a 2nd generation clonal seed orchard (CSO), while C. torelliana seed are available from 1st and 2nd generation SSOs. Breeding values (BV) have been developed for guiding the deployment of improved genotypes. Collaborative genetic improvement of these species is ongoing, including testing E. amplifolia in 11 countries and development of hybrid clones. Short Rotation Woody Crop (SRWC) systems may increase productivity and extend uses beyond conventional mulchwood to products such as medium density fiberboard (MDF), biochar, and energywood, while other possible applications include honey production, windbreaks, dendroremediation, and carbon sequestration. C. torelliana may be paired with E. grandis in two-row windbreaks to maximum windbreak effectiveness and may sequester as much carbon as E. grandis.

In Situ Wood Fiber Dyeing Through Laccase Catalysis for Fiberboard Production

The aim of the present work was to develop an innovative and environmentally friendly process for wood fiber dyeing and to produce 3-dimensionally fully colored medium-density fiberboard (MDF). The potential of laccase-catalyzed polymerization of selected precursors to form dyes useful in fiberboard manufacturing, a technique used for the first time in this field, was demonstrated. Some of the 7 aromatic compounds tested yielded colored products after laccase treatment under both acid and alkaline conditions, and a good variety of colors was attained by using mixtures of two different monomers. To demonstrate the coloration and design potential of laccase conversion of aromatic compounds, MDFs were enzymatically dyed using an in situ one-step laccase-catalyzed coloration process, and the results were compared against commercial MDFs obtained by using organic coloring agents. Important advantages over conventional processing methods include good color fastness and, in some cases, new hydrophobic properties, allowing designers and woodworkers to explore the beauty of textures and the use of simpler and milder processing conditions that eliminate harsh chemical use and reduce energy consumption.

Analysis of the Internal Mounting Forces and Strength of Newly Designed Fastener to Joints Wood and Wood-Based Panels

This study aimed to numerically and experimentally analyze the effects of internal mounting forces and selected materials on the stiffness and bending moment capacity of L-type corner joints connected with novelty-designed 3D printed fasteners. The experiments were carried out using medium-density fiberboard, high-density fiberboard, beech plywood, particleboard, and beech (Fagus silvatica L.) wood. The results showed that the joints made of beech wood were characterized by the largest bending moment capacity (12.34 Nm), while the worst properties were shown by particleboard (2.18 Nm). The highest stiffness was demonstrated by plywood joints (6.56 kNm/rad), and the lowest by particleboard (0.42 kNm/rad). Experimental studies have reasonably verified the results of numerical calculations. The test results confirmed that the geometry of new fasteners promotes the mounting forces under the assembly of the joints. It was shown that the higher the density of the materials, the greater the value of the mounting forces (164 N–189 N).

Experimental Investigation of Vertical Density Profile of Medium Density Fiberboard in Hot Press

This research investigates the performance of medium density fiberboard (MDF) with respect to hot press parameters. The performance of the board, type of glue, and production efficiency determine the optimum temperature and pressure for hot pressing. The actual temperature of the hot press inside the MDF board determines the properties of the final product. Hence, the optimal hot press parameters for the desired product are experimentally obtained. Moreover, MDF is experimentally investigated in terms of its vertical density profile, bending, and internal bonding under the various input parameters of temperature, pressure, cycle time, and moisture content during the manufacturing process. The experimental study is carried out by varying the temperature, pressure, cycle time, and moisture content in the ranges of 200–220 °C, 145–155 bar, 260–275 s, and 8–10%, respectively. Consequently, the optimum input parameters of a hot-pressing temperature of 220 °C, pressure of 155 bar, cycle time of 256 s, and moisture content of 8% are identified for the required internal bonding (0.64 N/mm2), bending (32 N/mm2), and increase in both the core and peak density of the vertical density profile as per the ASTM standard.

Comparison Failure and Successful Methodologies for Diffusion Measurements Undertaken inside Two Different Testing Rooms

The scattering phenomenon is known to be of great importance for the acoustic quality of a performance arts space. The scattering of sound can be achieved in different ways: it can be obtained by the presence of architectural and/or decorating elements inside a room (e.g., columns, statues), by the geometry and roughness of a surface (e.g., Quadratic Residue Diffuser (QRD)) and by the diffraction effect occurring when a sound wave hits the edges of an obstacle. This article deals with the surface scattering effects and the diffusion phenomenon only related to MDF and plywood panels tested by disposing the wells both horizontally and vertically. The test results undertaken inside a semi-reverberant room and inside a large reverberant room have been compared to highlight the success and the failure of the measuring methodologies. In detail, according to the existing standards and regulations (i.e., ISO 17497—Part 2), diffusion measurements have been undertaken on a few selected types of panel: two QRD panels (made of Medium Density Fiberboard (MDF) and plywood) with and without a smooth painted solid wood placed behind the QRD. The panels have been tested inside two rooms of different characteristics: a semi-anechoic chamber (Room A) and a large reverberant room (Room B). The volume size influenced the results that have been analyzed for both chambers, showing an overlap of reflections on panels tested inside Room A and a clear diffusion response for the panels tested inside Room B. In terms of the diffusion coefficient in all the octave bands between 125 Hz and 8 kHz, results should not be considered valid for panels tested in Room A because they were negatively impacted by extraneous reflections, while they are reliable for panels tested in Room B.

SHORT NOTES: APPLICATION OF MINERAL FILLER IN MEDIUM DENSITY FIBERBOARD (MDF) AND ITS EFFECT ON MATERIAL PROPERTIES AS A FUNCTION OF PARTICLE SIZE

The addition of inorganic filler material in medium density fiberboard (MDF) and the effect on material properties as a function of particle size was examined. Medium density fiberboard was manufactured in a laboratory scale environment to a target raw densityof 750 kgm-3. Wood fibers were replaced by using calcium carbonate at 3 and 10 wt.% using fillers with weighted median particle sizes of d50= 2.0 μm and d50= 30 μm, respectively. Urea formaldehyde resin was used as binder in all MDF. The influence of filler addition on the modulus of elasticity, bending and tensile strength, dimensional stability and liquid permeability was investigated. The results demonstrate the effect of filler content and its dependence on particle size. The addition of filler with d50= 30 μm does not have any influence on material properties up to a filler content of 10 wt.%. Using the finer filler with d50= 2.0 μm at 10 wt.% filler, the quantity significantly increases the water adsorption and swelling behavior and reduces the strength properties of the MDF.