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The objective of this study was to evaluate the potential use of solid wood waste of the following species Cedrela odorata, Enterolobium schomburgkii, Erisma uncinatum, and Qualea paraensis for the manufacture of edge glued panels. The quality of the finger joint and edge bonding with PVA and EPI adhesives, respectively, with spreading rates of 180 g.m-2, was evaluated through static bending, parallel tensile, and shear tests, using ASTM D 5572, EN 13353, and EN 13354 standards. A total of 1,460 test specimens exposed to dry, high temperature, triple cycle, and wet pre-treatments were tested for glue line resistance. The results of all tests for all pre-treatments of finger joints and edge bonding demonstrated the potential of wood waste for the manufacture of edge glued panels for interior use in dry environments. There was a tendency for resistance values to be balanced in splices and joints combined with mixtures of species, possibly due to the densities of the wood pieces. Wet pre-treatment delivered excellent lower 5th percentile results, highlighting the potential of Amazonian tropical solid wood waste for the production of edge glued panels.

In this study, three PLA-TPU compounds were prepared by the melt mixing method and after the process of compounding, filament preparation, and 3D printing with Fused Deposition Modeling (FDM). The mechanical properties under compression, tensile, bending, shear modes, and fracture toughness were comprehensively and experimentally assessed. Also, for thermal analysis and microstructural evaluation, Dynamic Mechanical Thermal Analysis (DMTA) and Scanning Electron Microscopy (SEM) were used. The thermal analysis of the PLA-TPU compounds showed an increase and decrease in the loss and storage modulus with increasing PLA value, while all compounds had almost the same glass transition temperature. The results of mechanical tests showed that by raising the amount of PLA, the strength and formability increased and decreased, respectively in all loading modes. The UTS values for PLA50, PLA70, and PLA90 were achieved 27.27 MPa, 40.91 MPa, and 54.18 MPa, respectively. Also, the fracture toughness results were consistent with the mechanical properties. The PLA90 had 1.69 and 2.36 times higher fracture toughness than the PLA70 and PLA50 compounds, respectively. SEM images showed that with the increase in the amount of TPU, the voids caused by the printing and neck growth due to the incomplete integration of the inter and intralayer rasters rises, which is the reason for the decrease in strength and printability. The shear test results also confirmed the SEM images quantitatively and showed that the connection between the layers and density improves with increasing the amount of PLA.

The proper choice of raw materials and manufacturing parameters for Cross Laminated Timber is essential to promote the proper bonding of the lamellas, aiming at their application in construction. However, few Brazilian species are currently used in the production of Cross Laminated Timber. The aim of this work was to characterize the bonding quality of four Brazilian reforestation species (Pinus elliottii, Eucalyptus grandis, Toona ciliata and Acrocarpus fraxinifolius) in the manufacture of Cross Laminated Timber with two-component polyurethane adhesive and five different pressure levels (from 0,1 MPa to 1,3 MPa). Bonding quality was evaluated through delamination and glue line shear tests based on the standard EN 14080 (2013). Delamination was affected by the wood species, and the best adhesion occurred for the Cross Laminated Timber manufactured with Pinus elliottii and Acrocarpus fraxinifolius at the bonding pressure of 0,7 MPa. Cross Laminated Timber bonding pressure did not affect the percentage of wood in the shear test fractured surface, whereas higher density Cross Laminated Timber showed higher percentages.

In this work, the effects of some geometric and mechanical parameters that characterize curved and relatively soft structures integrated with piezoelectric actuators are investigated. The effect of parameters such as the curvature, location, and extension of the piezo device, as well as the thickness of the bonding and its strength, are considered in view of a potentially lighter model that replaces the piezoelectric device via its actions, namely pin forces, whose layout and values are strongly dependent on the curvature. When comparing the results obtained by a finite element model of the structure with the piezo device and of the structure alone under the action of pin forces, dedicated indicators were found, which could be useful to support lighter modeling approaches and to predict the authority of the piezoelectric device.

The objective of this study was to analyze machining performance (characteristic and quality), as well as bonding quality of densified wood, and then compared to those of un-treated (control) wood and boron-treated wood. Characteristic and quality of machining properties were directly evaluated by qualified technician during processing, while bonding quality was evaluated through its shear strength. The results showed that densification employed was able to improve machining performance and bonding quality of the 5-year-old faster-grown teakwood. Compared to control wood and boron-treated wood, machining performances of densified teakwood are greater, while bonding quality increased by 18.79 and 26.86%, respectively. The surface became much fine and even, and has similar colour to older teakwood. Analysis hierarchy process (AHP) proves that densified teakwood is the best raw material for furniture manufacturing since its machining performances, appearance, colour, and bonding quality are better either than control wood or boron-treated wood.

Three-ply plywoods were produced using pine and Eucalyptus northeast Argentinian woods. A no-added formaldehyde biobased-adhesive was used for assembly, based on chemically modified soy protein concentrate. In this work we focused on the relationship between bonding quality parameters of the plywoods and the morphology of the glued line. Wood characteristics such as contact angle, roughness, density and moisture content were measured prior to plywood assembly. Bonding quality parameters (percentage of wood failure and shear strength) of the plywood were measured according to Argentinean standard IRAM 9562 and the results were evaluated with respect to microscopic observations of the glue joint. Eucalyptus wood was suitable for plywood interior condition applications, while pine barely exceeded the standards imposed by the norm.

The objective of this study was to evaluate the density, chemical properties and bonding quality of two lesser-used Mozambican wood species known as messassas (Brachystegia spiciformis and Julbernardia globiflora) aiming at edge-glued panel production. The bonding was performed using structural adhesive polyvinyl acetate D4, semi-structural adhesive emulsion polymer isocyanate and non-structural polyvinyl acetate D3 applied at 120·m-2 and 180·m-2 weights. Density, chemistry, edge shear bonding, wood failure percentage and the finger-joint tests were performed in accordance with ISO 13061-2:2014 (E), TAPPI, EN 13354:2008, ABNT-NBR ISO 12466-1:2006 and ASTM 5572:2005 standards, respectively. The results showed that both species have medium density, high extractives and lignin contents typical of tropical wood. The emulsion polymer isocyanate adhesive was approved with better performance compared to polyvinyl acetate D3 and D4 adhesives. It can also be affirmed that Brachystegia spiciformis and Julbernardia globiflora have similar bonding behaviour and the potential for producing edge glued panel panels, especially for indoor use.

By adding Na₂B₄O₇ into the Al-Fe₂O₃-Cr₂O₃ reaction system, the Al₂O₃ ceramic-lined steel pipe was prepared with the gravitational separation SHS method, and the influence of the Na₂B₄O₇ addition on the structure and properties of the produced composite steel pipe was investigated. The obtained results showed that the phase composition of the ceramic coating was Al₂O₃-FeCr Alloy-(Al0.9Cr0.1)₂O₃ composite, and with the increase of the amount of Na₂B₄O₇ addition, the Fe-Cr alloy particles left in the ceramic coating increased and distributed uniformly, and the denser ceramic coating was obtained. However, when the amount of Na₂B₄O₇ addition increased further to over 4%, the ceramic coating became fractures, the hardness of ceramic coating decreased. The transition structure of steel pipe-transition layer-ceramic coating was formed, the thickness of the transition layer decreased with the addition of Na₂B₄O₇, and the boundaries between the transition layer and the ceramic layer were less obvious, which would have a significant effect on the improvement of the bonding quality of the composite steel pipe.

The present paper investigates the physical and mechanical modifications of both poplar (I-214 clone) and ceiba veneers and plywood after heat treatments of different intensities (5 and 7 % of dry mass losses). Plywood panels were glued before and after heat treatment with urea-formaldehyde (UF) and melamine-urea-formaldehyde (MUF) resins. In order to assess the treatments’ effects on both the wood and the glues, the dry mass, the density, the bending strength, the Young’s modulus and the bonding quality were measured before and after heat treatment. The results of the different treatments were compared as well. Results showed that the loss in cell wall polymers due to the heat treatment caused a significant reduction of the equilibrium moisture content of the samples. From a mechanical point of view the treatment resulted in an important reduction of strength and in a small reduction of stiffness. Bonding quality as well as mechanical properties were widely affected by the heat treatment. The different intensities of the treatments (the treatment range was up to 5% and 7% of dry mass loss) did not show significant differences for most of the features assessed. The mechanical performance as well as the bonding quality of treated samples suggested that veneers should be glued after heat treatment. Apparent cohesive wood failure showed that different degradations affect wood and glues with a prominent effect on the glues for UF resins and a prominent effect on the wood for MUF resins.

Through using a novel micro-coating metal additive manufacturing (MCMAM) process in this study, the forming characteristics of the multilayer single-pass specimens were investigated. The forming defects including the porosity and the bonding quality between layers were analyzed. Moreover, we also attempted to study the effect of process parameters such as flow rate, deposition velocity, and layer thickness on the forming morphology. Based on the results, the optimization of process parameters was conducted for the fabrication of thin-wall MCMAM. Finally, estimation criteria for the integrity of the interfacial bond were established.