Changes in the Properties of Light-Irradiated Wood with Heat Treatment. Part 1. Effect of Treatment Conditions on the Change in Color

Holzforschung ◽  
2001 ◽  
Vol 55 (6) ◽  
pp. 601-605 ◽  
Author(s):  
K. Mitsui ◽  
H. Takada ◽  
M. Sugiyama ◽  
R. Hasegawa
Keyword(s):  
Heat Treatment ◽  
Chemical Composition ◽  
Relative Humidity ◽  
Sharp Increase ◽  
Temperature Treatment ◽  
Treatment Temperature ◽  
Low Temperature Treatment ◽  
Treatment Conditions ◽  
Short Period ◽  
Effect Of Treatment

Summary The effect of heat treatment on changing the color of light-irradiated wood was investigated. The change in the lightness, ∆L*, of light-irradiated wood with heat treatment was much greater than that of unirradiated wood. The chroma coordinates, ∆a*, of irradiated wood increased with treatment temperature and time. ∆b* decreased after showing a sharp increase with a short period of heat treatment. It is thought that the changes are related to a change in the chemical composition which was accelerated by heat. With low temperature treatment, the color of irradiated wood changed remarkably with high relative humidity. Little change in color was observed with low relative humidity. Therefore, heat and the presence of water accelerated the change in the color of irradiated wood. This treatment is available as a new coloring method.

Characteristics of Lithium Polysilicate Electrolyte Synthesized by Sol-Gel Processing

2007 ◽  
Vol 124-126 ◽  
pp. 1031-1034
Author(s):  
Bong Soo Jin ◽  
Bok Ki Min ◽  
Chil Hoon Doh
Keyword(s):  
Heat Treatment ◽  
Acid Treatment ◽  
Treatment Time ◽  
Sol Gel ◽  
Silicate Solution ◽  
Treatment Temperature ◽  
Lithium Silicate ◽  
Treatment Conditions ◽  
Xrd Patterns ◽  
Si Wafer

To find out suitable Si surface treatment and heat treatment conditions, acid treatment of Si wafer was done for lithium polysilicate electrolyte coating on Si wafer. In case of HCl treatment, the wet angle of a sample is 30o, which is the smallest wet angle of other acid in this experiment. Acid treatment time is 10 min, which is no more change of wet angle. Lithium polysilicate electrolyte was synthesized by hydrolysis and condensation of lithium silicate solution using perchloric acid. Thermal analysis of lithium polysilicate electrolyte shows the weight loss of ~23 % between 400 and 500 , which is due to the decomposition of LiClO4. The XRD patterns of the obtained lithium polysilicate electrolyte also show the decrement of LiClO4 peak at 400 . The optimum heat treatment temperature is below 400 , which is the suitable answer for lithium polysilicate electrolyte.

Changes caused by heat treatment in chemical composition and some physical properties of acacia hybrid sapwood

Holzforschung ◽  
2011 ◽  
Vol 65 (1) ◽  
pp. 67-72 ◽  
Author(s):  
Vu Manh Tuong ◽  
Jian Li
Keyword(s):  
Heat Treatment ◽  
Chemical Composition ◽  
Physical Properties ◽  
Water Absorption ◽  
Degradation Products ◽  
Interactive Effect ◽  
Treatment Temperature ◽  
Hydroxyl Group ◽  
Effect Of Temperature ◽  
Acacia Hybrid

Abstract Acacia hybrid (Acacia mangium×auriculiformis) sapwood was heat-treated in nitrogen under laboratory conditions for 2–6 h at 210°C–230°C. Chemical composition and physical properties including water absorption and swelling were examined. The results showed that these properties were reduced significantly by heat treatment, and there is an interactive effect of temperature and time on them. Chemical changes of the wood surface were determined by X-ray photo-electron spectroscopy analysis. Results indicate that the O/C ratio decreases as a function of treatment intensity due to the migration of extractives and degradation products to the surface during heat treatment. The C1s peaks showed an elevated content of lignin and extractives, whereas the hydroxyl group content was diminished with elevated treatment temperature. The O1s peaks revealed an increase in the O1 peak and confirmed the course of C1s peaks. These results coincide with the decrease in water absorption and swelling of wood after heat treatment.

scholarly journals Comparison of colors, microstructure, chemical composition and thermal properties of bamboo fibers and parenchyma cells with heat treatment

2021 ◽  
Vol 67 (1) ◽  
Author(s):  
Jieyu Wu ◽  
Tuhua Zhong ◽  
Wenfu Zhang ◽  
Jiangjing Shi ◽  
Benhua Fei ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Thermal Properties ◽  
Chemical Composition ◽  
Lignin Content ◽  
Treatment Temperature ◽  
Composition Analysis ◽  
Chemical Compositions ◽  
Cellulose Content ◽  
Parenchyma Cells ◽  
Bamboo Fibers

AbstractThe effects of heat treatment at various temperatures on mechanically separated bamboo fibers and parenchyma cells were examined in terms of color, microstructure, chemical composition, crystallinity, and thermal properties. The heat-treated parenchyma cells and fibers were characterized by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), chemical composition analysis, and thermogravimetric analysis (TGA). The results revealed that the colors of bamboo fibers and parenchyma cells were darkened as treatment temperature increased. The microstructure of the treated fibers and parenchyma cells slightly changed, yet the shape of starch granules in parenchyma cells markedly altered at a temperature of above 160 °C. The chemical compositions varied depending on the heat treatment temperature. When treated at 220 °C, the cellulose content was almost unchanged in fibers but increased by 15% in parenchyma cells; the hemicellulose content decreased and the lignin content increased regardless of fibers and parenchyma cells. The cellulose crystal structure was nearly unaffected by heat treatment, but the cellulose crystallinity of fibers changed more pronouncedly than that of parenchyma cells. The thermal stability of parenchyma cells after heat treatment was affected more substantially compared to fibers.

Fabrication and Characterization of Photocatalyst Coatings by Heat Treatment in Carbon Powder for TiC Coatings

2017 ◽  
Vol 263 ◽  
pp. 137-141
Author(s):  
Su Jun Guan ◽  
Liang Hao ◽  
Hiroyuki Yoshida ◽  
Hiroshi Asanuma ◽  
Fu Sheng Pan ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Oxygen Vacancies ◽  
Treatment Temperature ◽  
Carbon Powder ◽  
Treatment Conditions ◽  
Fabrication And Characterization ◽  
Mechanical Coating

Photocatalyst coatings on alumina (Al2O3) balls had been successfully fabricated by mechanical coating technique, with titanium carbide (TiC) powder and subsequent heat treatment in carbon powder. The effect of heat treatment conditions in carbon powder on the formed compounds, surface morphology and photocatalytic activity of photocatalyst coatings was investigated. XRD results show that the formed compounds change with increasing the heat treatment temperature in carbon powder, and rutile TiO2 on the surface of TiC coatings at 1073 K and 1173 K. The generated oxygen vacancies confirmed by XPS measurement, are in favor of narrowing band gap to enhance the visible-light photocatalytic activity of photocatalyst coatings. The photocatalytic activity of photocatalyst coatings has been effectively enhanced, and the samples fabricated at 1073 K and 1173 K for 2 h show higher activity. The fabrication strategy provides us a facile preparation procedure of visible-light responsive photocatalyst coatings.

Influence of Heat Treatment Conditions on Crystallization and Thermal Expansion of Las Glass-Ceramics

2010 ◽  
Vol 168-170 ◽  
pp. 1712-1716
Author(s):  
Zhuo Hao Xiao ◽  
Ming Hua Luo
Keyword(s):  
Heat Treatment ◽  
Thermal Expansion ◽  
Heat Treatment Temperature ◽  
Glass Ceramics ◽  
Treatment Temperature ◽  
Matrix Glass ◽  
Treatment Conditions ◽  
The Matrix ◽  
Crystal Phases ◽  
Quenching Method

The LAS glass containing P2O5has been prepared by conventional molten quenching method. The influence of heat treatment conditions on crystallization behavior, including phase transformation and microstructure, and thermal expansion coefficient (TEC) of Li2O–Al2O3–SiO2(LAS) glass-ceramics were investigated. DSC, XRD, SEM and TEC were used to detect the microstructure and properties of glass-ceramics under the different heat-treatment conditions. The results show the virgilite crystalline separated firstly from the matrix glass when heat treatment temperature was 850 °C. As the heat treatment temperature increased from 850 °C to 1050 °C, virgilite and β-spodumene were identified as main crystal phases. The TEC of glass-ceramics ranges from 0.5×10-6 °C-1to 2.8×10-6 °C-1, which is much lower than that of matrix glass.

Effect of Structure on the Mechanical Properties of PAN-Based Carbon Fibers during Graphitization

2011 ◽  
Vol 686 ◽  
pp. 770-777 ◽  
Author(s):  
Hao Xiao ◽  
Yong Gen Lu ◽  
Xian Ying Qin ◽  
Ya Wen
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Fiber Surface ◽  
Total Porosity ◽  
Interlayer Spacing ◽  
Temperature Treatment ◽  
Treatment Temperature ◽  
High Temperature Treatment ◽  
X Ray Diffraction ◽  
Crystallite Sizes

An investigation was conducted to determine the influence of high temperature treatment from 1600°C to 2800°C under stretching stress of 10MPa on PAN-based carbon fiber structure and physical properties. The tensile strength of fibers decreased from 4.5GPa to 2.97GPa with increasing treatment temperature up to 2800°C，while the modulus of fibers increased from 230GPa to 375GPa The texture in the longitudinal surface of fibers through heat treatment was characterized using a scanning electron microscopy. The contours of fiber surface became accidented with gaps becoming deeper as temperature increased. It has been observed that both the crystallite sizes (La, Lc) and the degree of preferred orientation increasd, while the crystallite interlayer spacing (d002) decreased by X-ray diffraction analysis with increasing heat-treatment temperature. The total porosity of fibers decreased from 21.01% to 15.09% and while the density of fibers increased from 1.720g/cm-3to1.886 g/cm-3with increasing heat-treatment. In addition, the relationship between mechanical properties and structure of variants was also explored in detail.

The Effect of Heat Treatment on the Shape Memory Effect of Ni-Ti Alloy Ultra-Thin Wires

2011 ◽  
Vol 332-334 ◽  
pp. 912-915
Author(s):  
Dan Zhang ◽  
Lei Xu ◽  
Rui Wang ◽  
Li Feng Xu
Keyword(s):  
Heat Treatment ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Crystal Morphology ◽  
Treatment Temperature ◽  
Ti Alloy ◽  
Thin Wires ◽  
Treatment Conditions

Various heat treatment conditions with temperature scans of 300-700 °C, and annealing time scans of 1-4 hours were adopted in the annealing of Ti-49.5at.%-Ni shape memory alloy ultra thin wires. The mechanical hysteretic curves and the crystal morphology were obtained by the tensile-recovery testing and scan electric microscopes (SEM). The result shows that the shape memory effect of Ni-Ti alloy first decline after rising with the heat treatment temperature increases. Alloy with heat treatment effect in 500°C, presents the best. Time is not a significant factor for heat treatment.

Influence of lime (CaO) on low temperature leaching of some types of bauxite from Guinea

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Marie Constance Béavogui ◽  
Irina Viktorovna Loginova ◽  
Ahmed Amara Konaté ◽  
Sékou Amadou Condé
Keyword(s):  
Chemical Composition ◽  
Low Temperature ◽  
Temperature Increase ◽  
Temperature Treatment ◽  
Bayer Process ◽  
Leaching Rate ◽  
Low Temperature Treatment ◽  
Leaching Efficiency

Abstract In Bayer process, low temperature treatment of bauxite generally applicable to gibbsite in the presence of a significant amount of boehmite (>3%), requires a temperature increase and the addition of an additive to improve the leaching conditions. This research is based on improvement of low temperature leaching conditions 108 °C and the addition of lime during the attack of some types of bauxite in Guinea. TRUhat is Low Mono Grade Bauxite (LMG), Standard Metal Grade (SMG) and Fria Bauxite (BF). The results of this study confirm an improvement in the extraction yields. Additionally, it shows an increase in yields of two points when the lime dosage is low, and between 0.5 and 3% of the bauxite weight. Based on the mineralogical and chemical composition findings, minerals contain of SMG bauxites are difficult to decompose while BF bauxites are easy to process. Sougueta limestone was used for testing. After calcination, we obtained CaO added at a rate of: 0.3; 0.5; 1; 3 and 6% of the bauxite weight to finally obtain the highest leaching efficiency compared to the leaching efficiency of bauxite without addition. The best leaching rate obtained for LMG, SMG and BF are respectively: 89.01, 87.15 and 89.74% for additions of 1, 0.5 and 3% CaO respectively.

scholarly journals Different Temperature Regimes Influenced the Quality of Broccoli Seedlings, Which Caused a Change in the Chemical Composition of Mature Heads

Agronomy ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1806
Author(s):  
Andrzej Kalisz ◽  
Joanna Gil ◽  
Edward Kunicki ◽  
Agnieszka Sękara ◽  
Andrzej Sałata ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Chemical Composition ◽  
Chemical Constituents ◽  
Chilling Stress ◽  
Soluble Sugars ◽  
Ascorbic Acid Content ◽  
Dry Weight ◽  
Temperature Treatment ◽  
Long Term Effects ◽  
Low Temperature Treatment

Exposure of vegetable seedlings to lowered temperature affects their growth and the content of certain chemical constituents. Chilling activates defensive mechanisms against stress and leads to acclimatization which increases plant ability to withstand harsh field conditions. Thus, seedlings subjected to low-temperature treatment had altered metabolic pathways, and these changes can persist until harvest. We therefore assessed: (i) the direct response of broccoli seedlings to 1 week or 2 weeks at lowered temperatures (6 °C, 10 °C, 14 °C, and 18 °C—control); and (ii) the long-term effects of the latter treatments on phytochemical components level in mature heads of broccoli cultivated in the field. Chilling stress decreased seedling shoot and root fresh and dry weights, plant height, number of leaves, leaf area, leaf perimeter, and leaf width. The most spectacular reductions in these parameters were observed at 6 °C and 10 °C. Longer exposure to lowered temperature resulted in greater reduction in the values of morphological traits. Chilling led to reduction in L-ascorbic acid content in broccoli seedlings, while a 6 °C temperature caused an increase in soluble sugars. The highest content of dry weight, soluble sugars, and L-ascorbic acid were observed in the heads of plants exposed to 14 °C; however, the content of dry weight (at 10 °C) and L-ascorbic acid (at 6 °C and 10 °C) also increased in broccoli heads in comparison with the control. Longer chilling (for 2 weeks) generally increased the content of these constituents in mature broccoli. Lower temperature (6–14 °C) applied at seedling stage increased P and Zn contents in broccoli heads in comparison to the control, whereas plants treated with 10 °C had more K, Fe, and, together with 6 °C treatment, Cu. The lowest temperature applied to the seedlings (6 °C) caused an increase in Mn content, while no effects of seedling chilling was noted for Ca levels. Significant linear correlations were noted and regression models were developed for the content of dry weight, soluble sugars, and L-ascorbic acid in the broccoli heads based on the chosen seedling parameters. The results show that the effect of lowered temperature to which the seedlings were subjected persists also in the further stages of plant ontogenesis, causing permanent changes in the chemical composition of mature broccoli heads.

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