Use of radiofrequency heating to glue wood products with polyvinyl acetate adhesives. Adhesive layers perpendicular to the electric field

Il manuale costituisce una trattazione pratica sull’utilizzo delle radiofrequenze per l’incollaggio di prodotti a base legnosa con adesivi acetovinilici. Esso ha quindi l’obiettivo di porsi come guida pratica per gli operatori del settore legno e funge da supporto per una migliore comprensione di tecnologie già in uso o innovative. Visto il taglio, il manuale colma una lacuna presente nella letteratura tecnico-scientifica. Oltre a una breve trattazione teorica dei principi generali del riscaldamento dielettrico, il manuale descrive i criteri per ottimizzare i parametri del generatore di radiofrequenze al fine di ottenere le migliori prestazioni del giunto incollato. Illustra inoltre i vantaggi dell’impiego di radiofrequenze in confronto al riscaldamento tradizionale (presse a caldo), soffermandosi in particolare sul bilancio tra risparmio energetico, costi di investimento e valutazione del rischio in termini di sicurezza nell’ambiente di lavoro. Nel manuale viene mostrato come vari tipi e classi di colle viniliche possono essere utilizzate con le radiofrequenze, che inducono lo sviluppo di energia termica in grado di avviare il processo di evaporazione dell’acqua dalla linea di colla

Structural Performance of a novel Interlocking Glued Solid Timber system

Purpose This paper introduces a novel Mass Timber Construction (MTC) system and presents the results of an initial exploration of its structural performance. This system is called Interlocking Glued Solid Timber (IGST) and employs standard-sized solid timber joists, glued together in overlapping patterns. Diagonal cuts are utilised in order to bond adjoining elements. Methods For the purposes of the tests described in this paper, a total of 70 spruce joists were collected at a sawmill and categorised via dynamic modulus of elasticity measurements. Materials testing provided the compressive strength perpendicular to the grain and the shear strength parallel to the grain. Three different types of IGST prototypes were manufactured and tested to failure in a four-point bending test. An additional two series were tested, one of solid joists and one of a glued joist. Three-dimensional finite element models (FEM) were also developed to perform numerical analyses. Results The results demonstrated that the ultimate capacity of one type of IGST prototype was very similar to that of a solid joist of equal cross-section. Conclusions As the IGST prototype if scalable, it could allow for applications similar to other MTC systems. Finally, the FEMs were generally accurate in predicting the performance of the IGST assemblies, thus allowing them to be used to simulate performance

Stabilizing Immature Dendritic Spines in the Auditory Cortex: A Key Mechanism for mTORC1-mediated Enhancement of Long-term Fear Memories

Mammalian target of rapamycin (mTOR) pathway has emerged as a key molecular mechanism underlying memory processes. Although mTOR inhibition is known to block memory processes, it remains elusive whether and how an enhancement of mTOR signaling may improve memory processes. Here we found in male mice that the administration of VO-OHpic, an inhibitor of the phosphatase and tensin homolog (PTEN) that negatively modulates AKT-mTOR pathway, enhanced auditory fear memory for days and weeks, while it left short-term memory unchanged. Memory enhancement was associated with a long-lasting increase in immature-type dendritic spines of pyramidal neurons into the auditory cortex. The persistence of spine remodeling over time arose by the interplay between PTEN inhibition and memory processes, as VO-OHpic induced only a transient immature spines growth in the somatosensory cortex, a region not involved in long-term auditory memory. Both the potentiation of fear memories and increase in immature spines were hampered by rapamycin, a selective inhibitor of mTORC1.These data revealed that memory can be potentiated over time by the administration of a selective PTEN inhibitor. Besides disclosing new information on the cellular mechanisms underlying long-term memory maintenance, our study provides new insights on the cellular mechanisms that aid enhancing memories over time.Significance StatementThe neuronal mechanisms that may help improve the maintenance of long-term memories are still elusive. The inhibition of mammalian-target of rapamycin (mTOR) signaling shows that this pathway plays a crucial role in synaptic plasticity and memory formation. However, if its activation may strengthen long-term memory storage is unclear. We assessed the consequences of positive modulation of AKT-mTOR pathway obtained by VO-OHpic administration, a phosphatase and tensin homolog inhibitor, on memory retention and underlying synaptic modifications. We found that mTOR activation greatly enhanced memory maintenance for weeks by producing a long-lasting increase of immature-type dendritic spines in pyramidal neurons of the auditory cortex. These results offer new insights on the cellular and molecular mechanisms that can aid enhancing memories over time

A peculiar Spanish Timber Floor, the "Revoltón": a Diagnostic Example at the "Palacio del Marqués de Benicarló"

The paper deals with the application of the Italian method for assessing on-site and diagnosing timber elements to a distinctive Spanish type of horizontal structure called "revolton" i.e. jack arch floor. As in Spain does not exist a specific regulation for the on-site diagnosis of timber elements, this analysis was performed according to the Italian standard UNI 11119. Due to the peculiar features of the jack arch floor some modifications were applied to the method. During spring 2012 the authors had the opportunity to carry out a pilot project by making a diagnostic analysis on a whole three stories building. The building, Marquees of Benicarlo's Palace, located in Spain in the town of Benicarlo, between Barcelona and Valencia, was erected during the second half of the XVIII century. It maintains the original internal distribution and structure, and it is characterized by precious ceramic decorations on walls and floors. All the horizontal structures studied inside the palace were jack arch floor except the roof structure that was also made of timber. The results of the project described in the paper clarify the specific problems of the horizontal structures and the roof surveyed during the fieldwork. These results are accompanied by several plans that represent the information recovered on-site and lead to a complete assessment of the structures. The plans include the grading based on wood defects, the local moisture content of wood, the superficial and inner decay due to insects and rot and the deformation of the joists. In this way it was possible to locate the areas of the palace where more problems were concentrated, and better understand the causes and origin of the damages.Diodato, M.; Macchioni, N.; Brunetti, M.; Pizzo, B.; Nocetti, M.; Burato, P.; Sozzi, L.... (2013). A peculiar Spanish Timber Floor, the "Revoltón": a Diagnostic Example at the "Palacio del Marqués de Benicarló". Advanced Materials Research. 778:1064-1071. doi:10.4028/www.scientific.net/AMR.778.1064S10641071778E. Cubero, El lujo señorial de lo sencillo (The noble luxury of simplicity), Revistart: Revista de las artes, 125 (2007) pp.8-10.C. Colón de Carvajal y Fibla, La casa-palacio de los Marqueses de Benicarló (The Marquees of Benicarló's Palace), Numen. Revista de excelencia, (2011) on-line.La casa de los Marqueses de Benicarló nos abre sus puertas (The Marquees of Benicarló's House opens its doors), MasQrural, 21 (2008) pp.85-94.M. Diodato, Variaciones constructivas y formales en forjados y cubiertas (Constructive and formal variations in floors and roofs), in: F. Vegas, C. Mileto, Valencia. Centro histórico. Ocho siglos de arquitectura residencial (Historic centre. Eight Centuries of residential architecture), Generalitat Valenciana, Valencia, (2013).N. Macchioni, Inspection techniques for ancient wooden structures, in: P. Roca, J.L. Gonzalez, E. Onate, P.B. Lourenco (Eds. ), Structural analysis of historical constructions II: possibilities of numerical and experimental techniques, CIMNE, Barcelona, 1998, pp.149-162.N. Macchioni, M. Piazza, Italian standardization activity in the field of diagnosis and restoration of ancient timber structures, in: F.M. Mazzolani (Ed. ), Protection of historical buildings - PROHITECH 09, vol. 1-2, Taylor & Francis Group, London, 2009, pp.349-353.G. Lear, B. Kasal, R. Anthony, Resistance drilling, in: B. Kasal, T. Tannert (Eds. ), In situ assessment of structural timber, State of the art report of the RILEM TC 215-AST, Springer.N. Macchioni, M. Brunetti, B. Pizzo, P. Burato, M. Nocetti, S. Palanti, The timber structures in the Church of the Nativity in Bethlehem: Typologies and diagnosis, Journal of cultural heritage, Vol. 13 Issue 4 Supplement S (2012) pp. E42-E53

Understanding Spanish Timber Jack Arch Floors: Examples of Assessment and Conservation Issues

[EN] Jack arch floors are structures made of timber joists, with round or squared section, and segmental vaults either made of flat tiles or poured plaster conglomerate. They are especially diffused along the Mediterranean coast of Spain and can be considered as a main feature of the historical and vernacular architecture of the area. In order to assess and grade these structures several Spanish standards have been considered; however, even if the information contained is useful the Italian standard for the on-site diagnosis UNI 11119 of 2004 has been preferred. The method described in this standard leads the assessment through the grading of each and every timber element and the assignation of bearing properties that are essential for the consolidation project. This article will expose three examples of jack arch floors of the Valencian Community graded using the Italian standard and the conservation issues that arise from the results.Diodato, M.; Macchioni, N.; Brunetti, M.; Pizzo, B.; Nocetti, M.; Burato, P.; Sozzi, L.... (2015). Understanding Spanish Timber Jack Arch Floors: Examples of Assessment and Conservation Issues. International Journal of Architectural Heritage. 9(6):641-654. https://doi.org/10.1080/15583058.2015.104119364165496Diodato, M., Macchioni, N., Brunetti, M., Pizzo, B., Nocetti, M., Burato, P., … Mileto, C. (2013). A Peculiar Spanish Timber Floor, the «Revoltón»: A Diagnostic Example at the «Palacio del Marqués de Benicarló». Advanced Materials Research, 778, 1064-1071. doi:10.4028/www.scientific.net/amr.778.1064Lear, G., Kasal, B., & Anthony, R. (2010). Resistance Drilling. RILEM State of the Art Reports, 51-57. doi:10.1007/978-94-007-0560-9_5Macchioni, N., Brunetti, M., Pizzo, B., Burato, P., Nocetti, M., & Palanti, S. (2012). The timber structures in the Church of the Nativity in Bethlehem: Typologies and diagnosis. Journal of Cultural Heritage, 13(4), e42-e53. doi:10.1016/j.culher.2012.10.004Riggio, M., Anthony, R. W., Augelli, F., Kasal, B., Lechner, T., Muller, W., & Tannert, T. (2013). In situ assessment of structural timber using non-destructive techniques. Materials and Structures, 47(5), 749-766. doi:10.1617/s11527-013-0093-6Tannert, T., Anthony, R. W., Kasal, B., Kloiber, M., Piazza, M., Riggio, M., … Yamaguchi, N. (2013). In situ assessment of structural timber using semi-destructive techniques. Materials and Structures, 47(5), 767-785. doi:10.1617/s11527-013-0094-5Vegas, F. (2013). Parameterisation of Gypsum Mortar for Alternative Structural Consolidation of Traditional Floors. Advances in Materials, 2(4), 48. doi:10.11648/j.am.20130204.1

Travels of a Rayed Head: imagery, fiber, structure and connotations of early textiles from the South Central Andes

The rayed head image has long been identified as a central symbol associated with the Paracas tradition, also called the sun face 1 and associated with the concept of Oculate Being developed by the Berkeley School. 2 Prominently repeated on the central ground of the famous Paracas Textile at the Brooklyn Museum, this image has much earlier antecedents in the region. Scholars disagree on the extent to which many Paracas, Topara and early Nasca images with large round eyes, grinning mouths, and serpentlike appendages emitting from the head and body may also be manifestations of a particular Oculate Being or of more general concepts of natural or supernatural power. Recently, contemporary textiles found in the Sihuas valley to the south (see Haeberli in this volume) challenge us to reexamine the similarities and distinctions among rayed heads. One of the great challenges of the history of material culture, envisioned as a history of philosophical concepts, social values and cultural practices through their inscription in material objects, is the degree to which a recurrent image, pattern or special arrangement reflects a similar idea. A number of quite different images have been associated with the concept of an Oculate Being proposed by John Rowe and others of the Berkeley school based on their analysis of Ica valley ceramics and Ocucaje gravelots in the 1950s. I here trace the rayed head or sun face image as it occurs over at least 500 years in the region of Ica and Paracas. I then briefly consider its relationship to other contemporary imagery and later imagery featuring ray-like elements emitted from the head, both in the same contexts where the rayed head appears, and in other cemeteries to the south in southern Peru and northern Chile. All the imagery discussed here is associated with a period between about 450 BC and AD 450 called the Formative in the South Central Andes (Bolivia and northern Chile) and called the Early Horizon (or late Formative) and Early Intermediate (or Regional Development) Period in the Central Andes. Most of the images I discuss are created on textiles. While only recovered from burials on the desert coast, textile materials draw on relationships of production and exchange that spanned the Andean cordillera to the montane rainforest to the east, and stretched to the north and south. Either as clothing or cargo, textiles themselves traveled and were no doubt a primary source of non-local imagery. I do consider related images on non-textile artifacts. I compare textile based imagery with contemporary imagery on engraved and painted ceramics and gourds to try to distinguish among design features specific to medium, style and iconography

Improvement of Water Resistance of Vegetable Proteins by the Use of Synthetic Origin Additives: Trials with Resins and Metal Ions

The adhesives industry is increasingly interested in products coming from natural and renewable resources. The aim of the present work was to improve the water resistance of soy-based proteins by using synthetic and formaldehyde-free additives. These include polyamide-amine epichlorohydrin (PAE), different types of isocyanates, and combinations of these cross-linkers between them and with other agents, including metal ions. In addition, the effect of both curing temperature and maturation time was assessed. Performances were evaluated by means of shear strength tests, solubility tests, and spectroscopic analysis. The obtained results showed that while isocyanates reacted completely but with water instead of proteins, tests with PAE were generally successful. In fact, the insoluble residue as well as the shear strength in wet conditions dramatically increased after PAE addition. Moreover, the wet performances of protein/PAE formulations appreciably increased gluing at 60 °C instead of room temperature. Furthermore, the maturation time had a positive effect on the formulations where metal ions were added, both for solubility and wet shear strength. Actually, for the very long conditioning time of 3 months, a significant and substantial increase of wet shear strength was observed for the series protein/PAE/aluminum