scholarly journals Influence of Natural and Artificial Weathering on the Colour Change of Different Wood and Wood-Based Materials

Forests ◽  
2018 ◽  
Vol 9 (8) ◽  
pp. 488 ◽  
Author(s):  
Davor Kržišnik ◽  
Boštjan Lesar ◽  
Nejc Thaler ◽  
Miha Humar
Keyword(s):  
Laboratory Test ◽  
Colour Change ◽  
Natural Weathering ◽  
Blue Staining ◽  
Artificial Weathering ◽  
Blue Stain Fungi ◽  
Colour Changes ◽  
Blue Stain ◽  
Positive Correlations ◽  
The Aesthetic

The importance of the aesthetic performance of wood is increasing and the colour is one of the most important parameters of aesthetics, hence the colour stability of twelve different wood-based materials was evaluated by several in-service and laboratory tests. The wood used for wooden façades and decking belongs to a group of severely exposed surfaces. Discolouration of wood in such applications is a long-known phenomenon, which is a result of different biotic and abiotic causes. The ongoing in-service trial started in October 2013, whilst a laboratory test mimicking seasonal exposure was performed in parallel. Samples were exposed to blue stain fungi (Aureobasidium pullulans and Dothichiza pithyophila) in a laboratory test according to the EN 152 procedure. Afterwards, the same samples were artificially weathered and re-exposed to the same blue stain fungi for the second time. The purpose of this experiment was to investigate the synergistic effect of weathering and staining. The broader aim of the study was to determine the correlation factors between artificial and natural weathering and to compare laboratory and field test data of fungal disfigurement of various bio-based materials. During the four years of exposure, the most prominent colour changes were determined on decking. Respective changes on the façade elements were significantly less prominent, being the lest evident on the south and east façade. The results showed that there are positive correlations between natural weathering and the combination of artificial weathering and blue staining. Hence, the artificial weathering of wood-based materials in the laboratory should consist of two steps, blue staining and artificial weathering, in order to simulate colour changes.

The chemistry of the blue stain fungi. Part 1. Some metabolites of Ceratocystis species associated with mountain pine beetle infected lodgepole pine

1986 ◽  
Vol 64 (5) ◽  
pp. 904-909 ◽  
Author(s):  
William A. Ayer ◽  
Lois M. Browne ◽  
Meow-Chen Feng ◽  
Helena Orszanska ◽  
Hussein Saeedi-Ghomi
Keyword(s):  
Mountain Pine Beetle ◽  
Blue Staining ◽  
Fungal Metabolites ◽  
Dihydroxybenzoic Acid ◽  
Phenyllactic Acid ◽  
Ergosterol Peroxide ◽  
Pine Beetle ◽  
Blue Stain Fungi ◽  
Hydroxyphenylacetic Acid ◽  
Blue Stain

Metabolites formed in still culture by Ceratocystisclavigera, C. ips, and C. huntii, three of the four Ceratocystis species associated with the blue stain disease of pine, have been identified. In addition to the ubiquitous fungal metabolites ergosterol, ergosterol peroxide, and fatty acids we have isolated succinic acid, β-phenethyl alcohol (1), tryptophol (2), prolylleucyl anhydride (3), tyrosol (4), 3-phenylpropane-1,2-diol (5), 6,8-dihydroxy-3-methylisocoumarin (8), 6,8-dihydroxy-3-hydroxymethylisocoumarin (9), p-hydroxybenzaldehyde (10), phenylacetic acid (11), p-hydroxyphenylacetic acid (12), phenyllactic acid (13), p-hydroxyphenyllactic acid (14), and 2,3-dihydroxybenzoic acid (15). The complex formed by chelation of iron with 2,3-dihydroxybenzoic acid may be responsible, at least in part, for the blue staining of the sapwood of diseased pine.

scholarly journals Comparison of Exterior Coatings Applied to Oak Wood as a Function of Natural and Artificial Weathering Exposure

Coatings ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 864
Author(s):  
Eliška Oberhofnerová ◽  
Kristýna Šimůnková ◽  
Ondřej Dvořák ◽  
Irena Štěrbová ◽  
Salim Hiziroglu ◽  
...  
Keyword(s):  
Laboratory Tests ◽  
Surface Wettability ◽  
Natural Weathering ◽  
Testing Time ◽  
Artificial Weathering ◽  
Oak Wood ◽  
Microscopic Evaluation ◽  
Colour Changes ◽  
Coating Durability ◽  
Pigmented Coatings

Artificial weathering can significantly reduce the testing time needed for proving coating durability, nevertheless its reliability is still not thoroughly proven. In this study, eight different transparent and pigmented coating systems, namely oil, acrylate, alkyd and urethane alkyd were evaluated through natural and artificial weathering tests on oak samples by measuring colour, gloss and surface wettability and by macroscopic and microscopic evaluation. The oil coatings performed well in wood colour stability evaluations, while the best gloss and wettability change results were noted for acrylate coatings. Pigmented coatings were characterized by significantly lower colour changes than transparent ones. The gloss and wettability changes were more sensitive to coating disruption than to total colour changes of coated wood associated with chemical changes in wood. The findings in this work showed that values of gloss changes and surface wettability for all types of coatings exposed to artificial and natural weathering resulted in significant differences from each other. The data obtained by artificial weathering method provide basic results of coatings durability and, ideally, natural weathering should be performed at the same time to support the results from laboratory tests by exposing wood under real conditions.

The study of colour changes under artificial weathering of light red meranti and yellow balau wood from Shorea genus

2020 ◽  
Vol 111 ◽  
pp. 37-42
Author(s):  
Agnieszka Jankowska
Keyword(s):  
Uv Irradiation ◽  
Wood Species ◽  
Wood Surface ◽  
Aging Process ◽  
Colour Change ◽  
Colour Stability ◽  
Artificial Weathering ◽  
Colour Parameters ◽  
Colour Changes ◽  
Weathering Process

The study of colour changes under artificial weathering of light red meranti and yellow balau wood from Shorea genus. This paper deals with the change in colour of selected tropical wood species from Shorea genus such as light red meranti and yellow balau. The artificial weathering method was used to determine the colour stability of wood surface. The used ageing method consisted of alternating soaking wood in water, drying at a temperature of 70°C and UV irradiation exposure. The colour changes were evaluated using CIE L*C*h system. Changes of particular colour parameters (lightness L*, chroma C*, hue h) were determine as well as the total colour change ΔE*. The results showed that tested species of wood change their colour similarly under the influence of the artificial weathering (the changes in the tested wood appearance occurred in similar scope). Surfaces of tested wood species initially became darker and then lighter. The largest changes in intensity of the colour of wood took place at the beginning of artificial weathering process. The intensity of changes decreased with the progress of aging process.

scholarly journals Alteration of Tissue Marking Dyes Depends on Used Chromogen during Immunohistochemistry

Cells ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 835
Author(s):  
Selina Kiefer ◽  
Julia Huber ◽  
Hannah Füllgraf ◽  
Kristin Sörensen ◽  
Agnes Csanadi ◽  
...  
Keyword(s):  
Colour Change ◽  
Residual Tumour ◽  
Blue Colour ◽  
Close Margin ◽  
Correct Orientation ◽  
Therapeutic Regime ◽  
Colour Changes ◽  
Tissue Specimens ◽  
Immunohistochemical Analyses ◽  
Colour Signal

Pathological biopsy protocols require tissue marking dye (TMD) for orientation. In some cases (e.g., close margin), additional immunohistochemical analyses can be necessary. Therefore, the correlation between the applied TMD during macroscopy and the examined TMD during microscopy is crucial for the correct orientation, the residual tumour status and the subsequent therapeutic regime. In this context, our group observed colour changes during routine immunohistochemistry. Tissue specimens were marked with various TMD and processed by two different methods. TMD (blue, red, black, yellow and green) obtained from three different providers (A, B and C, and Whiteout/Tipp-Ex®) were used. Immunohistochemistry was performed manually via stepwise omission of reagents to identify the colour changing mechanism. Blue colour from provider A changed during immunohistochemistry into black, when 3,3′-Diaminobenzidine-tetrahydrochloride-dihydrate (DAB) and H2O2 was applied as an immunoperoxidase-based terminal colour signal. No other applied reagents, nor tissue texture or processing showed any influence on the colour. The remaining colours from provider A and the other colours did not show any changes during immunohistochemistry. Our results demonstrate an interesting and important pitfall in routine immunohistochemistry-based diagnostics that pathologists should be aware of. Furthermore, the chemical rationale behind the observed misleading colour change is discussed.

scholarly journals Endemic Jeffrey Pine Beetle Associates: Beetle/Mite Fungal Dissemination Strategies and Interactions That May Influence Beetle Population Levels

2021 ◽  
Vol 9 (8) ◽  
pp. 1641
Author(s):  
Javier E. Mercado ◽  
Beatriz Ortiz-Santana ◽  
Shannon L. Kay
Keyword(s):  
Bark Beetle ◽  
Mountain Pine Beetle ◽  
Jeffrey Pine ◽  
Mutualistic Interaction ◽  
Pine Beetle ◽  
Blue Stain Fungi ◽  
Blue Stain ◽  
Grosmannia Clavigera ◽  
Mutualistic Fungus ◽  
Jeffrey Pine Beetle

Fungal and mite associates may drive changes in bark beetle populations, and mechanisms constraining beetle irruptions may be hidden in endemic populations. We characterized common fungi of endemic-level Jeffrey pine beetle (JPB) in western USA and analyzed their dissemination by JPB (maxillae and fecal pellet) and fungivorous mites to identify if endogenous regulation drove the population. We hypothesized that: (1) as in near-endemic mountain pine beetle populations, JPB’s mutualistic fungus would either be less abundant in endemic than in non-endemic populations or that another fungus may be more prevalent; (2) JPB primarily transports its mutualistic fungus, while its fungivorous mites primarily transport another fungus, and (3) based on the prevalence of yeasts in bark beetle symbioses, that a mutualistic interaction with blue-stain fungi present in that system may exist. Grosmannia clavigera was the most frequent JPB symbiont; however, the new here reported antagonist, Ophiostoma minus, was second in frequency. As hypothesized, JPB mostly carried its mutualist fungus while another fungus (i.e., antagonistic) was mainly carried by mites, but no fungal transport was obligate. Furthermore, we found a novel mutualistic interaction between the yeast Kuraishia molischiana and G. clavigera which fostered a growth advantage at temperatures associated with beetle colonization.

scholarly journals Indicator Layers Based on Ethylene-Vinyl Acetate Copolymer (EVA) and Dicyanovinyl Azobenzene Dyes for Fast and Selective Evaluation of Vaporous Biogenic Amines

Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4361
Author(s):  
Tinkara Mastnak ◽  
Aleksandra Lobnik ◽  
Gerhard Mohr ◽  
Matjaž Finšgar
Keyword(s):  
Biogenic Amines ◽  
Vinyl Acetate ◽  
Colour Change ◽  
Ethylene Vinyl Acetate ◽  
Yellow Orange ◽  
Colour Changes ◽  
Limit Sensitivity ◽  
Linear Concentration Range ◽  
Acetate Copolymer ◽  
Ethylene Vinyl Acetate Copolymer

The article presents naked-eye methods for fast, sensitive, and selective detection of isopentylamine and cadaverine vapours based on 4-N,N-dioctylamino-4′-dicyanovinylazobenzene (CR-528) and 4-N,N-dioctylamino-2′-nitro-4′-dicyanovinylazobenzene (CR-555) dyes immobilized in ethylene-vinyl acetate copolymer (EVA). The reaction of CR-528/EVA and CR-555/EVA indicator layers with isopentylamine vapours caused a vivid colour change from pink/purple to yellow/orange-yellow. Additionally, CR-555/EVA showed colour changes upon exposure to cadaverine. The colour changes were analysed by ultraviolet–visible (UV/VIS) molecular absorption spectroscopy for amine quantification, and the method was partially validated for the detection limit, sensitivity, and linear concentration range. The lowest detection limits were reached with CR-555/EVA indicator layers (0.41 ppm for isopentylamine and 1.80 ppm for cadaverine). The indicator layers based on EVA and dicyanovinyl azobenzene dyes complement the existing library of colorimetric probes for the detection of biogenic amines and show great potential for food quality control.

scholarly journals Colour Stabilization of Oak, Spruce, Larch and Douglas Fir Heartwood Treated with Mixtures of Nanoparticle Dispersions and UV-Stabilizers after Exposure to UV and VIS-Radiation

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1653 ◽  
Author(s):  
Miloš Pánek ◽  
Eliška Oberhofnerová ◽  
Štěpán Hýsek ◽  
Přemysl Šedivka ◽  
Aleš Zeidler
Keyword(s):  
Douglas Fir ◽  
Artificial Ageing ◽  
Visible Radiation ◽  
Aesthetic Value ◽  
Nanoparticle Dispersions ◽  
Individual Character ◽  
Colour Changes ◽  
The Aesthetic ◽  
Transparent Coatings ◽  
Hindered Amine Light Stabilizers

Colour changes and associated wood degradation in exterior and interior applications influenced by ultraviolet (UV) and visible radiation (VIS) decreases the aesthetic value of the products and shortens the overall life of transparent coatings. The aim of the paper is to achieve colour stabilization of oak, larch, Douglas fir and spruce heartwood via surface treatment with UV stabilizers, hindered amine light stabilizers (HALS), nanoparticles TiO2, ZnO, and mixtures thereof, during exposure to UV and VIS radiation. Colour changes were evaluated during accelerated artificial ageing testing in Xenotest. The distinctly individual character of colour changes in surface treatments due to the underlying wood species was confirmed. A synergistic effect was found when using a combination of active substances compared to substances used individually. The mixture of benzotriazoles with HALS (Tinuvin 5151) in combination with TiO2 and ZnO nanoparticles was confirmed as one of the most effective treatments for colour stabilization of wood due to UV and VIS spectrums.

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