Browsing by Author "Rodriguez-Grau, Gonzalo"

Now showing 1 - 5 of 5
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    Applicability of Paper and Pulp Industry Waste for Manufacturing Mycelium-Based Materials for Thermoacoustic Insulation
    (2024) Munoz, Hugo; Molina, Paulo; Urzua-Parra, Ignacio A.; Vasco, Diego A.; Walczak, Magdalena; Rodriguez-Grau, Gonzalo; Chateau, Francisco; Sancy, Mamie
    Cellulose and paper produce significant waste such as ash, activated sludge, and sludge from the pulp and paper industry. Depending on the raw material, legislation, and subprocesses, these sludges contain around 30-50% organic matter, mainly composed of less than 0.02 mm cellulose fibers and hemicellulose and lignin. This work used sludge from the pulp and paper industry as a substrate for manufacturing mycelium-based biomaterials using the white rot fungus Trametes versicolor. Chemical and surface analyses revealed the formation of new materials. Acoustic impedance analyses revealed that these materials have a noise reduction coefficient and sound absorption average comparable to extruded polystyrene and polyurethane. In addition, the material's thermal conductivity was near that of sheep wool. Therefore, the biomaterials fabricated using sludge and Trametes versicolor have the potential to be a game-changer in the industry as promising thermoacoustic insulators.
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    Feasibility of Bonding High-Moisture-Content Wood Using Nothofagus chilean Species
    (2023) Rosales, Victor; Rodriguez-Grau, Gonzalo; Galarce, Carlos; Montero, Claudio; Alvarado, Claudia; Munoz, Lisa; Pommier, Regis
    Appraising and protecting forests requires a management plan and the creation of innovative products for the market. The development of the green gluing technique could add value to native timber. However, there is a lack of knowledge concerning the response and the productive process of Nothofagus species using this technique. This work investigated the viability of implementing the green gluing method using three types of Nothofagus. Wood pieces were made using a one-component polyurethane adhesive. Delamination, shear tests, morphological characterization, and bond line thickness analysis tested their capacity. The results showed a variable response depending on the Nothofagus type, where the surface treatment could improve the green gluing performance. The findings highlight the relevance of increasing knowledge about the essayed species and their preparation to maintain their natural moisture condition.
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    Flexural performance assessment of the effect of the splice length of the Jupiter ray type made of radiata pine using computer-aided design and computer-assisted manufacturing
    (2024) Veliz-Fadic, Felipe Ignacio; Rodriguez-Grau, Gonzalo; Marin-Uribe, Carlos Rodolfo; Garcia-Giraldo, John Mario; Gonzalez-Palacio, Liliana; Araya-Letelier, Gerardo
    The length of timber beams of restricted commercial lengths can be increased by carpenter splices, which requires a thorough characterization of the flexural performance of these beams. An experimental study was carried out addressing timber beams joined with Jupiter ray splices to identify the influence of height-to-length (h:l) ratios of the splices on the mechanical performance in terms of deflection and flexural capacity. Jupiter ray splices with height-to-length (h:l) ratios of 1:2, 1:3, 1:4, and 1:5 were manufactured using computer-aided design (CAD) and computer-assisted manufacturing (CAM). The flexural performance of the tested beams was characterized in terms of modulus of rupture (MOR), modulus of elasticity (MOE), inelastic stiffness (K-inelastic), mid-span deflection (delta), and shear modulus values, measured using a four-point bending test setup under pure bending. Results indicate that implementing these joints reduces the flexural performance compared to equivalent solid timber beams without carpenter splices. The ratio concerning solid beams varies in ranges of 12-24 %, 26-43 %, 57-71 %, and 21-35 % of the corresponding solid beams average MOR, MOE, delta, and K-inelastic values, respectively. Moreover, a high linear correlation was observed between the average values obtained at the bending tests with h:l ratios in this study. Finally, the predominant failure patterns are described, identifying the critical points of stress concentration.
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    The Adhesion Performance in Green-Glued Finger Joints Using Different Wood Ring Orientations
    (2024) Rodriguez-Grau, Gonzalo; Cordonnier, Pierre-Louis; Navarrete, Benjamin; Montero, Claudio; Alvarado, Claudia; Pommier, Regis; Rosales, Victor; Galarce, Carlos
    Structural lumber is designed to meet the technical standards that ensure safety, cost-effectiveness, and sustainability. However, some tree species face limitations in their growth, which restricts their widespread use. An example of this is Nothofagus alpina, which has excellent mechanical properties but is not utilized much due to the challenges in extracting its timber and poor utilization, mainly because of the length of the wood. There is little information concerned with the uses and better management of small pieces using Nothofagus species, but it is still insufficient. This study investigates the adhesion performance of green-glued finger joints with varying wood ring orientations and moisture contents ranging from 21% to 25% using Nothofagus alpina. The primary aim is to assess how ring orientation and wet timber affect the green gluing process for creating larger wood pieces than sawn wood. The resulting products could meet the standards for wood serviceability number three for native Chilean wood. The findings indicate that finger joint performance improves with higher timber moisture levels. However, the orientation of the wood fibers did not significantly affect the performance under the tested conditions. It is important to note that this effect may become more significant near the fiber saturation point. These findings emphasize the need for a detailed protocol on the green gluing technique for Nothofagus alpina and the associated drying and surface processes in finger joint construction.
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    The Effect of the Addition of Copper Particles in High-Density Recycled Polyethylene Matrices by Extrusion
    (2022) Arcos, Camila; Munoz, Lisa; Cordova, Deborah; Munoz, Hugo; Walter, Mariana; Azocar, Manuel I.; Leiva, Angel; Sancy, Mamie; Rodriguez-Grau, Gonzalo
    In this study, the effect of the recycling process and copper particle incorporation on virgin and recycled pellet HDPE were investigated by thermo-chemical analysis, mechanical characterization, and antibacterial analysis. Copper particles were added to pellet HDPE, virgin and recycled, using a tabletop single screw extruder. Some copper particles, called copper nano-particles (Cu-NPs), had a spherical morphology and an average particle size near 20 nm. The others had a cubic morphology and an average particle size close to 300 nm, labeled copper nano-cubes (Cu-NCs). The thermo-chemical analysis revealed that the degree of crystallization was not influenced by the recycling process: 55.38 % for virgin HDPE and 56.01% for recycled HDPE. The degree of crystallization decreased with the addition of the copper particles. Possibly due to a modification in the structure, packaging organization, and crystalline ordering, the recycled HDPE reached a degree of crystallization close to 44.78% with 0.5 wt.% copper nano-particles and close to 36.57% for the recycled HDPE modified with 0.7 wt.% Cu-NCs. Tensile tests revealed a slight reduction in the tensile strength related to the recycling process, being close to 26 MPa for the virgin HDPE and 15.99 MPa for the recycled HDPE, which was improved by adding copper particles, which were near 25.39 MPa for 0.7 wt.% copper nano-cubes. Antibacterial analysis showed a reduction in the viability of E. coli in virgin HDPE samples, which was close to 8% for HDPE containing copper nano-particles and lower than 2% for HDPE having copper nano-cubes. In contrast, the recycled HDPE revealed viability close to 95% for HDPE with copper nano-particles and nearly 50% for HDPE with copper nano-cubes. The viability of S. aureus for HDPE was lower than containing copper nano-particles and copper nano-cubes, which increased dramatically close to 80% for recycled HDPE with copper nano-particles 80% and 75% with copper nano-cubes.