Material properties and nondestructive evaluation of laminated veneer lumber (LVL) made from Pinus oocarpa and P. kesiya

This study aimed at evaluating the mechanical, physical and biological properties of laminated veneer lumber (LVL) made from Pinus oocarpa Schiede ex Schltdl (PO) and Pinus kesiya Royle ex Gordon (PK) and at providing a nondestructive characterization thereof. Four PO and four PK LVL boards from 22 randomly selected 2-mm thickness veneers were produced according to the following characteristics: phenol-formaldehyde (190 g/m²), hot-pressing at 150°C for 45 min and 2.8 N/mm² of specific pressure. After board production, nondestructive evaluation was conducted, and stress wave velocity (v ₀) and dynamic modulus of elasticity (E _Md ) were determined. The following mechanical and physical properties were then evaluated: static bending modulus of elasticity (E _M ), modulus of rupture (f _M ), compression strength parallel to grain (f _c,0), shear strength parallel to glue-line (f _v,0), shear strength perpendicular to glue-line (f _v,90), thickness swelling (TS), water absorption (WA), and permanent thickness swelling (PTS) for 2, 24, and 96-hour of water immersion. Biological property was also evaluated by measuring the weight loss by Trametes versicolor (Linnaeus ex Fries) Pilát (white-rot) and Gloeophyllum trabeum (Persoon ex Fries.) Murrill (brown-rot). After hot-pressing, no bubbles, delamination nor warping were observed for both species. In general, PK boards presented higher mechanical properties: E _M , E _Md , f _M , f _c,0 whereas PO boards were dimensionally more stable, with lower values of WA, TS and PTS in the 2, 24, and 96-hour immersion periods. Board density, f _v,0, f _v,90 and rot weight loss were statistically equal for PO and PK LVL. The prediction of flexural properties of consolidated LVL by the nondestructive method used was not very efficient, and the fitted models presented lower predictability.     

Potential of structural pozzolanic matrix–hemp fiber grid composites

Currently, sustainability represents a primary issue for construction industry. New material and technological solutions are widely proposed and investigated to meet sustainability requirements and natural fibers represent one of the most studied materials. The work presented here investigated the mechanical behavior of a sustainable composite system made by pozzolanic mortar reinforced with hemp fiber grids. To improve the durability of the system and in particular of the fibers in the pozzolanic mortar environment a latex coating was used. The objective of the study was to investigate the mechanical behavior of the proposed composite system and assess the feasibility of using the system for structural retrofit applications on existing structures. A mechanical characterization of the fibers was conducted and the effectiveness of the latex coating in improving the durability of the fibers was investigated. The mechanical behavior of the composite system was studied, through a three-point bending test program.     

Advantages of a combined method of decalcification compared to EDTA

Decalcification of mineralized tissues is an essential step during tissue processing in the routine histopathology. The time required for complete decalcification, and the effect of decalcifier on cellular and tissue morphology are important parameters which influence the selection of decalcifying agents. In this study, we compared a decalcifying solution (ETDA) composed of both acid and chelating agents to a classical and well‐known decalcifying agent (EDTA). To this purpose, the optic density of bone radiographs, residual calcium analysis, bone sample weight, and histological and immunohistochemical analysis were performed. Our data suggest that, similarly to EDTA, the ETDA solution completely removes the calcium ions from the samples enabling easy sectioning. However, unlike the EDTA, this agent takes much less time. Furthermore, both agents showed comparable decalcification efficacy, and similarly, they did not produce cellular, tissue or antigenicity impairments. Therefore, ETDA may be a suitable option when it is necessary an association between a rapid and complete removal of calcium minerals, and a suitable preservation of structure and antigenicity of tissues. Microsc. Res. Tech. 78:111–118, 2015. © 2014 Wiley Periodicals, Inc.     

Equilibrium modified atmosphere packaging of wild strawberries

Wild strawberries (Fragaria vesca L.) are high‐added‐value fruits but their marketing is complex owing to their short postharvest life. In this work, equilibrium modified atmosphere packaging (EMAP) technology was used to maintain their quality and consequently to extend their life. Fresh strawberries were packaged with two continuous and three microperforated films (with different gas permeabilities) with the purpose of obtaining equilibrium atmospheres of diverse compositions. Weight loss, pH and acidity, solid content, colour, firmness, fungal decay and development of off‐flavours were selected to monitor fruit quality during 6 days at 10 °C. Among the five packages tested, microperforated films with one and three perforations provided adequate CO₂ and O₂ equilibrium concentrations in view of the evolution of chemical and physical quality parameters. These results were confirmed by sensory analysis. Copyright © 2007 Society of Chemical Industry