Istraživanje faktora trenja između furnira kao funkcije smjera protezanja vlakanaca i sadržaja vode

During the manufacture of veneer based moulded parts, veneers move against one another. Friction is caused due to this movement. Different conditions, such as gluing or fibre direction, could influence the friction coefficients and thus the moulding process. For a better understanding of the manufacturing process of veneer based moulded parts, it is important to know which parameters influence friction and friction coefficients. In this paper, results of friction investigations are presented. Thereby the moisture content of the used veneers was varied as well as the fibre direction. Considering the manufacture conditions, the investigations were also conducted with glue-coated veneers. The results prove an influence of fibre direction but this influence depends on moisture content.Tijekom proizvodnje furnirskih otpresaka furniri se gibaju jedan nasuprot drugome. Zbog toga gibanja nastaje trenje. Različiti uvjeti kao što su lijepljenje i smjer protezanja vlakanaca mogu utjecati na faktor trenja, a time i na proces izrade otpresaka. Za bolje razumijevanje procesa proizvodnje furnirskih otpresaka važno je znati koji čimbenici utječu na trenje i faktor trenja. U ovom su radu prezentirani rezultati istraživanja trenja između furnira. Varirani su sadržaj vode upotrijebljenih furnira, kao i smjer protezanja vlakanaca. Uzimajući u obzir i proizvodne uvjete, istraživanje se provodilo i s furnirima premazanim ljepilom. Rezultati su potvrdili utjecaj smjera protezanja vlakanaca, ali taj utjecaj ovisi o sadržaju vode u furniru

Identification of fungicidal components in poplar bark from short rotation plantations

Growth of mould fungi on packaging material reduces the product quality. Eco-fungicidal substances ensure an environmentally friendly approach to prevent this problem during the service life of the product. The bark of poplar trees, as a by-product of short rotation plantations, can be a new source for obtaining bio-fungicidal substances. The types and amount of the eco-fungicidal substances in different poplar clones were investigated with GC/MS and extracted from the raw material with different methods and adapted solvent series. After applying the eco-fungicidal substances to packaging material exposed to a mixture of mould fungi, the resistance against mould growth was monitored for several weeks. The bark extracts have shown promising results in reducing the growth speed of the mould and testing of separate fungicidal substances in the bark showed that substances such as phenol, chatecol and salicylic alcohol can prevent the mould growth.:1 Introduction 2 Material and Methods 2.1 Poplar bark 2.2 Bark Extraction 2.3 Bark fibre production 2.4 Laboratory sheets 2.5 Mould fungi 3 Results and discussion 3.1 Fungicidal components in poplar bark 3.2 Evaluating the fungicidal properties 4 Outlook 5 Acknowledgement 6 LiteratureEin Wachstum von Schimmelpilzen auf Verpackungsmaterialien reduziert deren Produktqualität. Biofungizide Substanzen stellen eine umweltfreundliche Variante zur Vermeidung dieses Problems während der Nutzungsdauer des Produktes dar. Pappelrinde als Nebenprodukt von Kurzumtriebsplantagen ist neue Quelle für die Gewinnung fungizider Substanzen. Art und Menge der biofungiziden Substanzen wurden mittels GC/MS untersucht, die geeigneten Substanzen wurden mittels verschiedener Methoden und angepasster Lösemittelreihen aus dem Rohmaterial gewonnen. Verpackungsmaterialien mit applizierten biofungiziden Substanzen wurden einer Mischung aus verschiedenen Schimmelpilzen ausgesetzt. Die Resistenz gegenüber dem Wachstum der Schimmelpilze wurde über mehrere Wochen beobachtet. Die Rindenextrakte zeigten vielversprechende Ergebnisse bei der Reduzierung der Geschwindigkeit des Wachstums der Schimmelpilze. Die Prüfung ausgewählter, in der Rinde vorhandener Substanzen hat gezeigt, dass beispielsweise Phenol, Brenzcatechin und Salizylalkohol das Wachstum von Schimmelpilzen einschränken kann.:1 Introduction 2 Material and Methods 2.1 Poplar bark 2.2 Bark Extraction 2.3 Bark fibre production 2.4 Laboratory sheets 2.5 Mould fungi 3 Results and discussion 3.1 Fungicidal components in poplar bark 3.2 Evaluating the fungicidal properties 4 Outlook 5 Acknowledgement 6 Literatur

Zone line formation on artificial media and in hardwoods by basidiomycetes for production of spalted wood

One of the visual modification of wood is the formation of dark zone lines (ZLs) via interaction of fungi. The result is called spalted wood, which has hitherto been produced mainly in small batches. The main goal of the present study is to further develop techniques for rapid formation of ZLs in hardwoods. Various white rot and brown rot fungi were tested to this purpose. Initially, interactions of 148 combinations of 17 basidiomycetes in malt extract agar were evaluated and their antagonistic interactions were characterised in order to identify fungal pairs capable of rapidly forming high-quality ZLs. Six types of interactions were observed, among others; antibiosis and inhibition in contact, which differ in terms of variables including mycelial overgrowth and zone line formation. Furthermore, 23 pairs of ZL forming fungi on malt extract agar were identified. Then the interactions of five selected pairs of fungi grown on the hardwood species Acer pseudoplatanus L., Betula pendula Roth. and Populus nigra L. were examined to assess their utility for controlled mycological wood modification, also in terms of a possible substrate dependency of their interactions. The results indicate that Lentinus tigrinus fungus is one of the best and quickest producer of ZLs in mycological wood modification

Composites en matières premières renouvelables et leurs procédés

National audienceThe development of new bio-based composites and efficient manufacturing methods that are suitable for series processing is the purpose of the current sub-project C4 of the Excellence Cluster MERGE, sponsored by DFG (Deutsche Forschungsgemeinschaft). Two different types of materials are combined: bio-based thermoplastic biopolymers such as bio-polyethylene (BioPE) or bio-polyamides (BioPA) and renewable reinforcing materials such as thin wood veneer or unidirectional flax fibers. To achieve a high-efficiency in terms of mass-production, reproducibility and flexibility, it is required to overlap several steps in the realization of semi-finished and final products. The improvement of the adhesion at the interface of the components, the implementation of continuous processes in order to increase energetically the yielding and the final design, through several methods, for the future potential applications are so many perspectives to achieve. MOTS-CLÉS : polymère bio-basé thermoplastique; renforcement naturel (Lin ou placage en bois) ; Amélioration de l'adhésion à l'interface matrice/renforcement ; Procédés plastic/textile continu ; Application dans l'automobile et équipement sportifsLe développement de matériaux bio-basés et de méthodes efficaces de mise en forme, adaptable à la production en série, est le but de l'actuel sous-projet C4 du programme d'excellence MERGE financé par la DFG (Deutsche Forschungsgemeinschaft). Ainsi, deux types de matériaux sont combinés : Des polymères bio-ressourcés thermoplastiques tels que bio-polyéthylène (BioPE) ou bio-polyamide (BioPA) et des matériaux de renforcements renouvelables tels que le placage en bois ou des fibres de lin unidirectionnelles continues. Pour atteindre un haut rendement en termes de production en masse, de reproductibilité et de flexibilité, il est requis de suivre plusieurs étapes dans la réalisation de produits semi-finis et finis. L'amélioration de l'adhésion à l'interface des composantes, la mise en place de procédés continus afin d'augmenter leur rendement, et la mise en forme finale, par diverses méthodes, pour des futures potentiels applications sont autant d'objectifs à atteindre

Production of natural colorants by liquid fermentation with Chlorociboria aeruginascens and Laetiporus sulphureus and prospective applications

The replacement of potentially hazardous synthetic dyes with natural dyes and pigments are of great interest for a sustainable economy. In order to obtain cost-efficient, environmentally friendly and competitive products, improvements in the cultivation and extraction of pigment-producing organisms and in dyeing processes are necessary. In our study, we were able to scale up the production of xylindein by Chlorociboria aeruginascens from 3 to 70 L bioreactor cultivations. We have identified important bioprocess parameters like low shear stress (150 rpm, tip speed <0.5 m/s) for optimal pigment yield (4.8 mg/L/d). Additionally, we have demonstrated the potential of laetiporic acid production by Laetiporus sulphureus in various cultivation systems and media, achieving dried biomass concentrations of almost 10 g/L with a 7 L bioreactor cultivation after 17 days. Extractions performed at 70°C and 15 min incubation time showed optimal results. To the best of our knowledge, we have described for the first time the use of this pigment in silk dyeing, which results in a brilliant hue that cannot easily be produced by other natural pigments. © 2020 The Authors. Engineering in Life Sciences published by Wiley-VCH Gmb

70 years of wood modification with fungi

To obtain special wood properties for various technical applications, fungi with their broad spectrum of activity can make a contribution. The foundations for today's mycological wood modifications were laid by researchers who wanted to increase the yield of edible mushrooms. They noticed the changed properties of the wooden substrate by the progressive wood degradation. Controlled use of fungi and an eye for the technical benefits of mycologically degraded wood revolutionized the fundaments of wood modification, primarily biological. In this context, the so-called Myko-Holz (myco-wood) plays a unique role and influences the current research for pencil wood, tone wood or even spalting

Transfer of the Interlaminar Shear Test to Veneer Layer-based Composites for Qualitative Evaluation of Layer Adhesion

This study aimed to investigate the suitability of the interlaminar shear (ILS) testing method for veneer-based composites. The ILS testing method is an established method for composite materials as a qualitative evaluation of the adhesion within the composite. The applicability of this method to veneer based composites enables a simple qualitative statement on the adhesion of the individual layers. The ILS method complements existing wood-based material tests that focus on bonding, using significantly smaller material dimensions

Testing of set recovery of unmodified and furfurylated densified wood by means of water storage and alternating climate tests

Densification is a well-known method for improving the mechanical properties of wood. In the present study, unmodified and furfurylated wood samples were densified and submitted to cyclic water storage tests and cyclic alternating climate tests. Swelling coefficients and spring-back data were determined for the evaluation of the quality of densification. The study shows that results depend on the test method applied. Simple water storage tests do not reflect the behavior of densified wood in the high humidity range. The spring-back data of unmodified samples are more influenced by the testing method than those of the furfurylated ones