The impact of drying and steaming processes on surface color changes of tension and normal beech wood

The drying process was examined relative to parameters’ influence on the deformation and surface layer color changes of beech wood (Fagus sylvatica L.) and oak wood (Quercus robur L.). The goal was to analyze the impact of drying process conditions, wood and growth rings types, and load on the deformation and surface color changes of drying thin wooden elements. A further aim was to reduce the time of the lamella drying and minimize wood products defects. During each drying, 40 pieces of wood were dried, divided into two groups. For the first group, 30 pieces were dried under a uniformly distributed load of approximately 50 kg, while for the second group, 10 samples were dried without weight. The lamellas dried under load exhibited fewer cup, bow, and twist deformations than the lamellas dried without load. Cracks in the dried lamellas occurred comparably in those dried under and without load. Color changes in the specimens before and after drying were observed and measured. The differences in colorimetric parameters (a, b, and L) between wood without defects and with defects were less marked after drying than before drying. The color changes were only noticed in the surface layers of the specimens.

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Impact of Preharvest and Postharvest on Color Changes during Convective Drying of Mangoes

Foods ◽

10.3390/foods10030490 ◽

2021 ◽

Vol 10 (3) ◽

pp. 490

Author(s):

Alioune Diop ◽

Jean–Michel Méot ◽

Mathieu Léchaudel ◽

Frédéric Chiroleu ◽

Nafissatou Diop Ndiaye ◽

...

Keyword(s):

Regression Models ◽

Convective Drying ◽

Color Changes ◽

Ripening Time ◽

Physico Chemical ◽

C 30 ◽

The Impact

The purpose of this study was to evaluate the impact of the harvest stage, ripening conditions and maturity on color changes of cv. ‘Cogshall’ and cv. ‘Kent’ variety mangoes during drying. A total of four harvests were undertaken, and the fruits were ripened at 20 and 35 °C for five different ripening times at each temperature. At each ripening time, mangoes were dried at 60 °C/30% RH/1.5 m/s for 5 h. A wide physico-chemical and color variability of fresh and dry pulp was created. The relationships according to the L*, H* and C* coordinates were established using mixed covariance regression models in relation to the above pre- and postharvest (preprocess) parameters. According to the L* coordinate results, browning during drying was not affected by the preprocess parameters. However, dried slices from mangoes ripened at 35 °C exhibited better retention of the initial chroma, and had a greater decrease in hue than dried slices from mangoes ripened at 20 °C. However, fresh mango color, successfully managed by the pre- and postharvest conditions, had more impact on dried mango color than the studied parameters. The preprocess parameters were effective levers for improving fresh mango color, and consequently dried mango color.

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Treatment of wood with atmospheric plasma discharge: study of the treatment process, dynamic wettability and interactions with a waterborne coating

Holzforschung ◽

10.1515/hf-2020-0182 ◽

2020 ◽

Vol 0 (0) ◽

Author(s):

Jure Žigon ◽

Matjaž Pavlič ◽

Pierre Kibleur ◽

Jan Van den Bulcke ◽

Marko Petrič ◽

...

Keyword(s):

Plasma Treatment ◽

Treatment Process ◽

Beech Wood ◽

Treated Wood ◽

Plasma Discharge ◽

Contact Angles ◽

Atmospheric Plasma ◽

Waterborne Coating ◽

Spruce Wood ◽

The Impact

AbstractPlasma treatment is becoming a mature technique for modification of surfaces of various materials, including wood. A better insight in the treatment process and the impact of the plasma on properties of wood bulk are still needed. The study was performed on Norway spruce and common beech wood, as well as their thermally modified variations. The formations of the airborne discharge, as well as mass changes of the treated wood, were monitored. The impact of such treatment on wood-coating interaction was investigated by evaluating the dynamic wettability and penetration into wood. At the wood surface, plasma streamers were observed more intense on denser latewood regions. Wood mass loss was higher with increasing number of passes through the plasma discharge and was lower for thermally modified wood than for unmodified wood. Plasma treatment increased the surface free energy of all wood species and lowered the contact angles of a waterborne coating, these together indicating enhanced wettability after treatment. Finally, the distribution and penetration depth of the coating were studied with X-ray microtomography. It was found that the coating penetrated deeper into beech than into spruce wood. However, the treatment with plasma increased the penetration of the coating only into spruce wood.

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Fusarium graminearum Colors and Deoxynivalenol Synthesis at Different Water Activity

Foods ◽

10.3390/foods8010007 ◽

2018 ◽

Vol 8 (1) ◽

pp. 7 ◽

Cited By ~ 3

Author(s):

Edgar Cambaza ◽

Shigenobu Koseki ◽

Shuso Kawamura

Keyword(s):

Fusarium Graminearum ◽

Color Change ◽

High Growth ◽

Cereal Crops ◽

Color Analysis ◽

Surface Color ◽

Color Changes ◽

White Mycelium ◽

Imagej Software ◽

Inverse Proportionality

Deoxynivalenol (DON) is a well-known mycotoxin, responsible for outbreaks of gastrointestinal disorders in Japan. Fusarium graminearum, a parasite of cereal crops, produces this toxin and this is one of the reasons why it is important to understand its metabolism. It is possible to predict the mold’s color change and the quantity of DON synthesized throughout its lifecycle. Furthermore, aw has been found to affect the amount of DON. This study aimed to analyze the potential of F. graminearum surface color as a predictor of DON concentration at aw = 0.94, 0.97, and 0.99. Thus, 36 specimens were incubated at 25 °C, 12 at each aw. After 4, 8, 12, and 16 days, three specimens from each aw were collected for color analysis and DON quantification. For color analysis, photos were taken and red, green and blue (RGB) channels were measured on ImageJ software. DON was quantified through liquid chromatography (HPLC). Color changes were only observed at aw = 0.99 because at lower aw the molds presented high growth of white mycelium. Yet, DON increased in all cases. It was only possible to relate the colors with DON concentration at aw = 0.99, where they presented inverse proportionality.

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The Impact of Paraffin-Thermal Modification of Beech Wood on Its Biological, Physical and Mechanical Properties

Forests ◽

10.3390/f10121102 ◽

2019 ◽

Vol 10 (12) ◽

pp. 1102 ◽

Cited By ~ 3

Author(s):

Ladislav Reinprecht ◽

Miroslav Repák

Keyword(s):

Mechanical Properties ◽

Bending Strength ◽

Beech Wood ◽

Physical And Mechanical Properties ◽

Brown Rot ◽

European Beech ◽

White Rot ◽

White Rot Fungus ◽

Poria Placenta ◽

The Impact

The European beech (Fagus sylvatica L.) wood was thermally modified in the presence of paraffin at the temperatures of 190 or 210 °C for 1, 2, 3 or 4 h. A significant increase in its resistance to the brown-rot fungus Poria placenta (by 71.4%–98.4%) and the white-rot fungus Trametes versicolor (by 50.1%–99.5%) was observed as a result of all modification modes. However, an increase in the resistance of beech wood surfaces to the mold Aspergillus niger was achieved only under more severe modification regimes taking 4 h at 190 or 210 °C. Water resistance of paraffin-thermally modified beech wood improved—soaking reduced by 30.2%–35.8% and volume swelling by 26.8%–62.9% after 336 h of exposure in water. On the contrary, its mechanical properties worsened—impact bending strength decreased by 17.8%–48.3% and Brinell hardness by 2.4%–63.9%.

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Weath ering Performance of Beech Wood Coated with Acrylic Paint Containing UV Stabilizers of Dihydroxy Benzophenone and Nano Zinc Oxide

Drvna industrija ◽

10.5552/drvind.2020.1912 ◽

2020 ◽

Vol 71 (4) ◽

pp. 403-409

Author(s):

Mehrnaz Akbarnezhad ◽

Davood Rasouli ◽

Hossein Yousefi ◽

Mahdi Mashkour

Keyword(s):

Contact Angle ◽

Zinc Oxide ◽

Beech Wood ◽

Mold Growth ◽

Acrylic Paint ◽

Color Changes ◽

Acrylic Coating ◽

Nano Zinc Oxide ◽

Water Based ◽

Nano Zinc

In this study, the effect of UV stabilizers (dihydroxy benzophenone and nano zinc oxide) on the weathering degradation of water-based acrylic coating on beech wood was investigated. The wood specimens were coated by brush and then weathered naturally for six months. The obtained results showed that the use of nano zinc oxide reduced color changes and mold growth on the surface of weathered samples. However, the results of contact angle, pull-off adhesion, colorimeter and FTIR revealed that the dihydroxyl benzophenone was not effective in preventing weathering degradation of coated wood.

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Wood Surface Changes of Heat-Treated Cunninghamia lanceolate Following Natural Weathering

Forests ◽

10.3390/f10090791 ◽

2019 ◽

Vol 10 (9) ◽

pp. 791

Author(s):

Xinjie Cui ◽

Junji Matsumura

Keyword(s):

Heat Treatment ◽

Wood Surface ◽

Color Change ◽

Thermal Modification ◽

Protective Measure ◽

Surface Color ◽

Natural Exposure ◽

Heat Treated ◽

The Impact ◽

Cunninghamia Lanceolate

To quickly clarify the effect of heat treatment on weatherability of Cunninghamia lanceolate (Lamb.) Hook., we investigated the surface degradation under natural exposure. A comparison between heat-treated and untreated samples was taken based on surface color changes and structural decay at each interval. Over four weeks of natural exposure, multiple measurements were carried out. Results show that color change decreased in the order of 220 °C heat-treated > untreated > 190 °C heat-treated. The results also indicate that the wood surface color stability was improved via the proper temperature of thermal modification. Low vacuum scanning electron microscopy (LVSEM) results expressed that thermal modification itself had caused shrinking in the wood surface structure. From the beginning of the weathering process, the heat treatment affected the surface structural stability. After natural exposure, the degree of wood structure decay followed the pattern 220 °C heat-treated > 190 °C heat-treated > untreated. Therefore, when considering the impact on the structure, thermal modification treatment as a protective measure to prevent weathering was not an ideal approach and requires further improvement.

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Peroxide Post-Treatment of Wood Impregnated with Micronized Basic Copper Carbonate

Coatings ◽

10.3390/coatings10121213 ◽

2020 ◽

Vol 10 (12) ◽

pp. 1213

Author(s):

Rod Stirling ◽

Gabrielle Boivin ◽

Adnan Uzunovic ◽

Stacey Kus ◽

John N. R. Ruddick

Keyword(s):

Color Change ◽

Treated Wood ◽

Post Treatment ◽

Fungal Resistance ◽

Copper Carbonate ◽

Photo Degradation ◽

Color Changes ◽

Copper Leaching ◽

The Impact ◽

Increased Susceptibility

Wood is vulnerable to significant color changes when used in exterior applications. Some copper-based wood preservatives use colorants to minimize this color change. This paper examines the ability of a peroxide post-treatment to turn wood impregnated with micronized basic copper carbonate (CuCO3·Cu(OH)2) (MBCC) a stable brown color. MBCC-treated wood, with and without peroxide post-treatment, along with associated controls were evaluated for color change, erosion and black-stain fungal resistance after exposure to artificial photo-degradation. The impact of the peroxide treatment on copper leaching was assessed in a laboratory experiment, and the impact on copper reactivity was assessed by electron parametric resonance (EPR) spectroscopy. Peroxide post-treatment of wood pressure impregnated with MBCC was shown to reduce color change by more than 50% compared to controls. Erosion due to photo-degradation and colonization by black-stain fungi were lower in samples treated with MBCC than in untreated controls and were relatively unaffected by peroxide post-treatment. The peroxide post-treatment was associated with increased amounts of mobile copper. This led to increased susceptibility to leaching and to a more than 60% increase in the amount of copper than had reacted with the wood.

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