Improvement of Heartwood Color of Black-Colored Sugi (Cryptomeria japonica D. Don) by UV Irradiation after Smoke Heating

Holzforschung ◽  
2000 ◽  
Vol 54 (3) ◽  
pp. 294-300 ◽  
Author(s):  
Futoshi Ishiguri ◽  
Kikuko Saitoh ◽  
Minoru Andoh ◽  
Zensaku Abe ◽  
Shinso Yokota ◽  
...  
Keyword(s):  
Metal Ions ◽  
Uv Irradiation ◽  
Cryptomeria Japonica ◽  
Treated Wood ◽  
Hot Water ◽  
Sodium Potassium ◽  
Color Changes ◽  
Red Color ◽  
Treatment Changes ◽  
Weak Acidic Condition

Summary Black-colored heartwood of sugi (Cryptomeria japonica D. Don) logs with bark attached were smoked, heated, and smoke-heated separately to improve the heartwood color. After each treatment, changes of heartwood color, amounts of extracts (hot water, 1 % sodium hydroxide, and ethanol-toluene), metal ions (sodium, potassium, calcium and magnesium), and pH were examined. In addition, changes of heartwood color by UV irradiation (wavelength at 254 nm and 365 nm) also were studied. Heating and smoke-heating of logs prevented blackening of the heartwood, leading to a yellow-white heartwood color, whereas smoking did not largely change the heartwood color. Almost no differences in the amounts of extracts and metal ions were found in the control and treated woods. Thermal and smoke treatments decreased the pH from the original 8.1 to 6.0 and 7.4, respectively. The results obtained suggest that the changes of pH by both heating and smoking relate to the heartwood color changes in black-colored sugi. In the heated and smoke-heated woods, redness and yellowness were increased by the subsequent UV irradiation at 365 nm, whereas brightness was decreased. Apparently, the heartwood color of black-colored sugi was changed from yellow-white to red by the UV irradiation, the red color being the normal heartwood color of sugi. However, UV irradiation did not cause significant changes in the heartwood color in the control and smoked woods. These results suggest that UV irradiation of the thermally treated wood showing the resulting yellow-white color recovered the redness as found in normal red-colored heartwood, which seems to be caused by chemical changes of pigments under a weak acidic condition in the black-colored heartwood of sugi.

scholarly journals Surface and Physical Features of Thermo-Mechanically Modified Iroko and Tauari Wood for Flooring Application

Coatings ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1528
Author(s):  
Agnieszka Laskowska ◽  
Monika Marchwicka ◽  
Agata Trzaska ◽  
Piotr Boruszewski
Keyword(s):  
Sessile Drop ◽  
Color Space ◽  
Treated Wood ◽  
Contact Angles ◽  
Hydraulic Press ◽  
Hot Water ◽  
Densified Wood ◽  
Extractive Content ◽  
Dimensional Changes ◽  
Color Changes

The aim of the study was to determine the selected surface and physical properties of iroko (Milicia excelsa (Welw.) C.C. Berg) and tauari (Couratari spp.) wood after thermo-mechanical treatment (TMT) in relation to extractive content. During TMT, no chemicals are introduced into the wood, which distinguishes this method from a number of wood modification methods. The iroko and tauari wood were subjected to volumetric densification in a hydraulic press. The wood was densified in a radial direction at a temperature of 100 and 150 °C. The wood color parameters were measured using the mathematical CIE L*a*b* and L*C*h color space models. The roughness parameters of Ra and Rz parallel and perpendicular to the grain were investigated. The contact angle (CA) of the wood with distilled water was determined based on the sessile drop method. The equilibrium moisture content (EMC) and dimensional changes of the wood were determined for a climate with a temperature of 20 °C and a relative humidity (RH) of 9%, 34%, 55%, 75% and 98%. The tauari wood was less prone to color changes under the influence of TMT than the iroko wood. After densification, the iroko and tauari wood displayed a different character of roughness changes. The iroko wood featured the lowest level of roughness after TMT at 100 °C, and the tauari wood after TMT at 150 °C. The densified iroko and tauari wood were characterized by weaker dynamics in the changes in their respective contact angles than the non-densified wood. The higher the temperature of the TMT, the lower the EMC of the wood. Higher EMC values were observed for the tauari wood than for the iroko wood. This was due to the lower content of chloroform-ethanol extractives. Similar dependencies were obtained in the case of hot water extractives. The thermo-mechanically treated wood displayed a greater tendency towards dimensional changes in a climate with high relative air humidity, i.e., above 70%, compared to the non-modified wood.

Reddening by UV Irradiation after Smoke-Heating in Sugi (Cryptomeria japonica D. Don) Black Heartwood

Holzforschung ◽  
2001 ◽  
Vol 55 (4) ◽  
pp. 347-354 ◽  
Author(s):  
Saori Maruyama ◽  
Futoshi Ishiguri ◽  
Minoru Andoh ◽  
Zensaku Abe ◽  
Shinso Yokota ◽  
...  
Keyword(s):  
Thermal Treatment ◽  
Uv Irradiation ◽  
Cryptomeria Japonica ◽  
Color Change ◽  
Ph Value ◽  
Uv Light ◽  
Japanese Cedar ◽  
Color Changes ◽  
Black Heartwood ◽  
Thermally Treated

Summary Sugi (Japanese cedar, Cryptomeria japonica D. Don) green logs with black heartwood were smoked, heated, and smoke-heated separately to improve the heartwood color. After each treatment, changes in heartwood color, pH, and extract amounts were examined. In addition, changes in heartwood color caused by UV irradiation were observed. Heating and smoke-heating of logs prevented the heartwood from discoloring to black, and the resulting color of thermally-treated heartwoods was yellow-white, whereas smoking alone allowed discoloration to black. The pH value decreased from the original 7.6 to 6.8 by smoking and to 6.5 by thermal treatment. The results obtained here suggest that a pH drop in heartwood by thermal treatment is involved in color changes of black heartwood. When thermally-treated black heartwood was exposed to UV light, redness and yellowness increased and brightness decreased. The resulting color tone was reddish brown. The color of non-thermally-treated woods, however, showed little change. Furthermore, acetone, ethanol, and methanol extracts of thermally-treated black heartwood showed an increase in redness by UV irradiation, but the residues showed little color change. The coloring substances relating to the reddening of heartwood could be extracted with these solvents, particularly with methanol. Reddening in black heartwood by a combination of smoke-heating and UV irradiation is considered to be due to a decrease in brightness and an increase in both redness and yellowness.

scholarly journals Metal Binding Proteins

Encyclopedia ◽  
2021 ◽  
Vol 1 (1) ◽  
pp. 261-292
Author(s):  
Eugene A. Permyakov
Keyword(s):  
Metal Ions ◽  
Metal Binding ◽  
Transition Metal Ions ◽  
Short Review ◽  
Sodium Potassium ◽  
Physical Chemical ◽  
Physiological Properties ◽  
Cell Processes ◽  
Living Organisms ◽  
Potassium Magnesium

Metal ions play several major roles in proteins: structural, regulatory, and enzymatic. The binding of some metal ions increase stability of proteins or protein domains. Some metal ions can regulate various cell processes being first, second, or third messengers. Some metal ions, especially transition metal ions, take part in catalysis in many enzymes. From ten to twelve metals are vitally important for activity of living organisms: sodium, potassium, magnesium, calcium, manganese, iron, cobalt, zinc, nickel, vanadium, molybdenum, and tungsten. This short review is devoted to structural, physical, chemical, and physiological properties of proteins, which specifically bind these metal cations.

Red color enhancement of sugi (Cryptomeria japonica D. Don) heartwood by light irradiation

1999 ◽  
Vol 45 (3) ◽  
pp. 271-273 ◽  
Author(s):  
Shang-Tzen Chang ◽  
Sheng-Yang Wang ◽  
Sen-Sung Cheng
Keyword(s):  
Cryptomeria Japonica ◽  
Light Irradiation ◽  
Red Color ◽  
Color Enhancement

AMMONOLYSIS OF URONIC ESTER GROUPS IN BIRCH XYLAN

1964 ◽  
Vol 42 (11) ◽  
pp. 2434-2439 ◽  
Author(s):  
Paul Y. Wang ◽  
H. I. Bolker ◽  
C. B. Purves
Keyword(s):  
Alkaline Hydrolysis ◽  
Uronic Acid ◽  
Liquid Ammonia ◽  
Treated Wood ◽  
Hot Water ◽  
Amide Nitrogen ◽  
White Birch

Solvent-extracted white birch, kept near 20° in liquid ammonia under pressure for 72 h and then extracted with methanol to remove acetamide, retained 0.25% of amide nitrogen. Extraction of the very finely ground residual wood with hot water yielded 21% as a 4-O-methylglucuronoxylan containing 0.53% of amide nitrogen. Alkaline hydrolysis removed the amide absorption in the infrared and restored the normal xylan spectrum. These results, supported by various control experiments, showed that amide groups in the ammonia-treated wood were derived from lactone or ester groups in the original 4-O-methylglucuronoxylan. Some of the uronic acid groups in the native wood presumably existed as ester crosslinks.

Comparison of the color and weight change in Paulownia tomentosa and Pinus koraiensis wood heat-treated in hot oil and hot air

BioResources ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. 5574-5585
Author(s):  
Intan Fajar Suri ◽  
Jong Ho Kim ◽  
Byantara Darsan Purusatama ◽  
Go Un Yang ◽  
Denni Prasetia ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Color Change ◽  
Treated Wood ◽  
Pinus Koraiensis ◽  
Weight Changes ◽  
Paulownia Tomentosa ◽  
Wood Color ◽  
Color Changes ◽  
Hot Air ◽  
Heat Treated

Color changes were tested and compared for heat-treated Paulownia tomentosa and Pinus koraiensis wood treated with hot oil or hot air for further utilization of these species. Hot oil and hot air treatments were conducted at 180, 200, and 220 °C for 1, 2, and 3 h. Heat-treated wood color changes were determined using the CIE-Lab color system. Weight changes of the wood before and after heat treatment were also determined. The weight of the oil heat-treated wood increased considerably but it decreased in air heat-treated wood. The oil heat-treated samples showed a greater decrease in lightness (L*) than air heat-treated samples. A significant change in L* was observed in Paulownia tomentosa. The red/green chromaticity (a*) of both wood samples increased at 180 and 200 °C and slightly decreased at 220 °C. The yellow/blue chromaticity (b*) in both wood samples increased at 180 °C, but it rapidly decreased with increasing treatment durations at 200 and 220 °C. The overall color change (ΔE*) in both heat treatments increased with increasing temperature, being higher in Paulownia tomentosa than in Pinus koraiensis. In conclusion, oil heat treatment reduced treatment duration and was a more effective method than air heat treatment in improving wood color.

Extractives relating to heartwood color changes in sugi (Cryptomeria japonica) by a combination of smoke-heating and UV radiation exposure

2003 ◽  
Vol 49 (2) ◽  
pp. 135-139 ◽  
Author(s):  
F. Ishiguri ◽  
S. Maruyama ◽  
K. Takahashi ◽  
Z. Abe ◽  
S. Yokota ◽  
...  
Keyword(s):  
Radiation Exposure ◽  
Uv Radiation ◽  
Cryptomeria Japonica ◽  
Color Changes

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

Coatings ◽  
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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