Microstructure, mechanical, and thermogravimetric characterization of cellulosic by-products obtained from biomass seeds

The microstructural, thermal, and nanomechanical characterization of biomass by-products coming from the food industry were studied. Scanning electron microscopy showed a microstructure formed by polygonal grains. The thermal behavior of seeds, evaluated by thermogravimetric analysis, revealed three main components (hemicellulose, cellulose, and lignin). Walnut shell showed the highest thermal stability and also the highest amount of lignin. The nanomechanical aspects were evaluated by nanoindentation. Samples with higher amount of cellulose presented minor modulus values. In accordance with the thermal stability, the highest modulus and hardness were observed in walnut. These by-products could be useful as reinforcement materials for biodegradable plastic industry.This work has been supported by the Spanish Ministry of Science and Innovation (MAT2011-28468-C02-02) and the Autonomous Government of Valencia (Spain) through the research program Geronimo Forteza (62/2010, 9 de Junio DOCV no 6291). M.P. Arrieta is granted by Santiago Grisolia program (GRISOLIA/2011/007).Rayón Encinas, E.; Ferrándiz Bou, S.; Rico Beneito, MI.; López Martínez, J.; Arrieta, MP. (2015). Microstructure, mechanical, and thermogravimetric characterization of cellulosic by-products obtained from biomass seeds. International Journal of Food Properties. 18(6):1211-1222. https://doi.org/10.1080/10942912.2014.884578S1211122218

THERMOPLASTIC STARCH/WOOD COMPOSITES: INTERFACIAL INTERACTIONS AND FUNCTIONAL PROPERTIES

Thermoplastic starch (TPS)/wood composites were prepared from starch plasticized with 36 wt% glycerol. The components were homogenized by dry-blending, extruded and injection molded to tensile bars. Tensile properties, structure, deformation, water adsorption and shrinkage were determined as a function of wood content, which changed between 0 and 40 vol% in 7 steps. The modification of TPS with wood particles improves several properties considerably. Stiffness and strength increases, and the effect is stronger for fibers with larger aspect ratio. Wood fibers reinforce TPS considerably due to poor ma-trix properties and strong interfacial interactions, the latter resulting in the decreased mo-bility of starch molecules and in the fracture of large wood particles during deformation. Strong interfacial adhesion leads to smaller water absorption than predicted from additivity, but water uptake remains relatively large even in the presence of wood particles. The shrinkage of injection molded TPS parts is very large, around 10 %, and dimensional changes occur on a very long timescale of several hundred hours. Shrinkage decreases to a low level already at 15-20 vol% wood content rendering the composites good dimensional stability

Wood in the cultural heritage of the Cyclades Islands: species, uses, protection

Τhe limited acknowledgement of wood as one of the most significant parts of Greek cultural heritage, despite its continuous and versatile exploitation, leads gradually to the degradation of valuable wooden structures of the past, due to biological factors and implemented renovations, especially in areas such as the Cyclades islands, where the shortage of wood production forests has created the distorted view of the absence of such constructions. The present thesis aims to identify and record the wooden structural or stable decorative elements and mechanisms that were constructed until the end of the 19th century in the Cyclades islands (Folegandros, Milos, Kimolos, Kythnos, Anafi, with emphasis on Sikinos island) and to analyze the most typical and remarkable ones, by specifying the wood species used for their manufacturing, with a view to contribute to the highlighting, acknowledgement and protection of them. Ιn reference to the building constructions, most of the old structures are manufactured using the «flat roof» technique, involving visible beams, which vary in shape and species of wood depending on the island and use, although, in most cases, almost unprocessed logs of the species of juniper, native to several islands, were used, whose short length determined the dimensions and proportions of buildings. Concerning the utilization of wood in mechanisms construction, all islands include abandoned windmills, some of which retain the whole or part of the old mechanisms, with the highest number of them being found in the islands of Kythnos (6 mechanisms) and Folegandros (5 mechanisms), while the lower number is detected in the island of Milos, as the majority of windmills have nowadays been converted into houses. These mechanisms generally have the same basic characteristics, although some differences were identified in the individual components and wood species, which are various, showing however some specialization and almost exclusive use of hardwood species. Regarding the hand-crafted wood carved iconostases, their number is high in most of the islands, although the products transfer has been a laborious and costly process in those days. Most of them are located on the islands of Sikinos and Milos and only few of them on the island of Anafi, while Sikinos island includes 13 old churches bearing wood carved iconostases. Many of them constitute exceptional artworks, constructed mainly with cypress wood, although in mainland of Greece mostly wood from hardwood species was used, a fact strongly associated with the influences from the island of Crete. As it was concluded in the present thesis, the Cyclades islands have a great wealth of old structures, partly or entirely made of wood, which constitute an important component of the cultural heritage and have not yet been acknowledged, unlike other areas of Greece. Particularly the island of Sikinos, which has preserved its traditional wooden structures to a considerable extent, could become a «model» island for highlighting the wood-related cultural heritage, as part of properly organized management, which will be consistent with a new way of attracting tourism and primarily with the respect to the protection and preservation of this unknown cultural treasure of Greece.Η περιορισμένη ανάδειξη της αξίας του ξύλου ως στοιχείου της ελληνικής πολιτιστικής κληρονομιάς, παρά τη συνεχή και πολυδιάστατη αξιοποίησή του, οδηγεί σταδιακά στην καταστροφή αξιόλογων κατασκευών του παρελθόντος, εξαιτίας βιολογικών παραγόντων και ανακαινίσεων, ειδικά σε περιοχές όπως είναι οι Κυκλάδες, όπου η έλλειψη ξυλοπαραγωγικών δασών έχει δημιουργήσει μία διαχέουσα άποψη περί απουσίας τέτοιων κατασκευών. Σκοπός της παρούσας διδακτορικής διατριβής ήταν ο εντοπισμός και η καταγραφή ξύλινων δομικών ή σταθερών διακοσμητικών στοιχείων ή μηχανισμών που κατασκευάστηκαν μέχρι τα τέλη του 19ου αιώνα σε νησιά των Κυκλάδων (Φολέγανδρος, Μήλος, Κίμωλος, Κύθνος, Ανάφη, με έμφαση στη νήσο Σίκινο) και στη μελέτη των πιο αντιπροσωπευτικών και πιο αξιόλογων από αυτά, με προσδιορισμό του είδους ξύλου που χρησιμοποιήθηκε για την κατασκευή τους, έχοντας ως απώτερο στόχο την προβολή και την προστασία τους. Όσον αφορά στις δομικές κατασκευές, η πλειονότητα των παλαιών κτισμάτων είναι κατασκευασμένα με την τεχνική του δώματος, περιλαμβάνοντας εμφανείς δοκούς, με τη μορφή και το είδος ξύλου να διαφέρει εν μέρει ανάλογα με το νησί και τη χρήση, αν και στην πλειονότητα χρησιμοποιήθηκαν σχεδόν ακατέργαστοι κορμοί από το αυτοφυές σε αρκετά κυκλαδίτικα νησιά είδος της αρκεύθου, το μικρό μήκος των οποίων καθόρισε τις διαστάσεις και τις αναλογίες των κτισμάτων. Όσον αφορά στη χρήση του ξύλου στην κατασκευή ξύλινων μηχανισμών, όλα τα νησιά περιλαμβάνουν εγκαταλελειμμένους ανεμόμυλους, κάποιοι από τους οποίους διατηρούν στην πλειονότητα ή εν μέρει τους παλαιούς μηχανισμούς, με το μεγαλύτερο αριθμό να εντοπίζεται στα νησιά Κύθνο (6 μηχανισμοί) και Φολέγανδρο (5 μηχανισμοί), ενώ ο μικρότερος αριθμός εντοπίζεται στη νήσο Μήλο, καθώς η πλειονότητα των ανεμόμυλων έχει πλέον μετατραπεί σε οικίες. Οι εν λόγω μηχανισμοί εμφανίζουν γενικά τα ίδια βασικά χαρακτηριστικά, αν και διαπιστώθηκαν κάποιες διαφορές σε επιμέρους εξαρτήματα, αλλά και στα χρησιμοποιούμενα είδη ξύλου που είναι ποικίλα, με κάποια ωστόσο εξειδίκευση και αποκλειστική σχεδόν χρήση πλατύφυλλων ειδών. Όσον αφορά στα χειροποίητα ξυλόγλυπτα τέμπλα, ο αριθμός τους είναι μεγάλος στην πλειονότητα των νησιών, παρόλο που η μεταφορά τους κατά το παρελθόν αποτελούσε δύσκολη και πολυδάπανη διαδικασία. Τα περισσότερα βρίσκονται στα νησιά Σίκινο και Μήλο και τα λιγότερα στη νήσο Ανάφη, με τη Σίκινο να διαθέτει 13 παλαιούς ναούς που φέρουν χειροποίητα ξυλόγλυπτα τέμπλα. Πολλά από αυτά αποτελούν εξαιρετικά έργα τέχνης, κατασκευασμένα σε μεγάλο ποσοστό από ξύλο κυπαρισσιού, αν και στην ηπειρωτική Ελλάδα χρησιμοποιήθηκαν εκτεταμένα τα πλατύφυλλα είδη, γεγονός που συνδέεται με κρητικές επιρροές. Όπως διαπιστώθηκε στην παρούσα διατριβή, τα κυκλαδίτικα νησιά παρουσιάζουν μεγάλο πλούτο παλαιών κατασκευών, αποτελούμενες εν μέρει ή εξ ολοκλήρου από ξύλο, οι οποίες συνιστούν σημαντικό τμήμα της πολιτιστικής κληρονομιάς και δεν αναδείχθηκαν μέχρι σήμερα, σε αντίθεση με άλλα μέρη της Ελλάδας. Ιδιαίτερα η νήσος Σίκινος, η οποία έχει διατηρήσει αναλλοίωτες, σε σημαντικό βαθμό, τις παραδοσιακές ξύλινες κατασκευές της, θα μπορούσε να αποτελέσει ένα νησί πρότυπο για την ανάδειξη της πολιτιστικής κληρονομιάς που σχετίζεται με το ξύλο, ως τμήμα ενός οργανωμένου, νέου τρόπου προσέγγισης της τουριστικής ανάπτυξης, παρουσιάζοντας πρωτίστως σεβασμό στην προστασία του άγνωστου αυτού πολιτιστικού θησαυρού της Ελλάδας

Wood Utilization in Windmill Mechanisms on Sikinos Island (Greece)

Windmills constitute a valuable part of cultural heritage, especially in Greece, as unique structures of popular architecture and know-how of the pre-industrial era. Their wooden mechanisms were of exceptional constructional ingenuity, with the Mediterranean ones bearing a vertical wing and a rotating roof (“trula”), with a manual torsion mechanism that allowed for operation in all wind directions. Sikinos is a small Aegean island characterized by rich landscapes, which do not have wood-producing forests, but only sparse Juniperus phoenicea shrub land mixed with evergreen hardwood species and the presence of numerous sclerophyllus vegetation species (maquis). Three abandoned windmills are still preserved on the island today, but only two of them appear to have their wooden mechanisms left. In the one windmill mechanism examined, it was found that different wood species were used to manufacture its individual parts. Oak wood was used in most of the large elements, with the exception of the sprattle beam (“zigos”), which is made of fir wood. The local juniper was not used in any crucial part of the mechanism, though it was used only as a structural material on the first floor (“anogio”) flooring, along with large-diameter olive trunks. The findings of this study highlighted the thorough knowledge of the properties of various wood species and the effective use of simple tools toward the construction of functional and effective windmill mechanisms