scholarly journals Color Change of Birch Wood During Thermal Exposure

2017 ◽  
Vol 7 (3) ◽  
pp. 15-21 ◽  
Author(s):  
Михаил Ермоченков ◽  
Mihail Ermochenkov ◽  
Андрей Хроменко ◽  
Andrey Khromenko
Keyword(s):  
Heat Treatment ◽  
Thermal Decomposition ◽  
Thermal Degradation ◽  
Color Change ◽  
Thermal Exposure ◽  
Thermal Modification ◽  
Birch Wood ◽  
Color Characteristics ◽  
Physical And Chemical ◽  
Kinetics Of

Heat treatment is widely used to improve the properties of wood. Such processes include drying and thermal modification. Thermal modification is heating wood without oxygen, accompanied by heat destruction. Thermally modified wood can be used as structural and finishing materials. This puts the task of determining its thermal and physical, physical and chemical, biological, and ornamental properties and their change during heat treatment. The article presents the results of experimental and computational studies of color characteristics of the wood of birch, their change in the process of thermal modification. Thermal decomposition is a complicated multi-stage physical and chemical process. Thermal decomposition of material causes changes in its composition, structure, accompanied by alterations of its properties. Wood can be considered as a multicomponent composite material, consisting of hemicellulose, cellulose, lignin and other components. Each component decomposes in the temperature range that causes the multistage process of thermal degradation. The degree of thermal degradation of the material is determined by the kinetics of occurrence of each stage and the degree of its perfection. Thermal decomposition kinetics of wood can be determined by the results of thermal and gravimetric experiments. In the article the model of determining the color characteristics of wood as a function of the degree of completion of individual stages of thermal degradation is suggested. Model of decomposition of color for RGB components is used for identifying. Color identification of the samples of original birch wood in RGB coordinates was performed. The parameters of thermal effects, allowing to obtain wood with given degree of thermal decomposition are defined. Heat treatment of samples and identification of their color is made. The dependence of RGB parameters from time and intensity of heat treatment is studied. Empirical relations to determine the identifying characteristics of color, as a function of the degree of completion of stages of thermal destruction, in RGB and LAB systems are obtained in explicit form.

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

Forests ◽  
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.

INFLUENCE OF HEAT TREATMENT ON AROMA AND COLOR CHARACTERISTICS OF WHEAT BREAD

2021 ◽  
Author(s):  
И.М. ПОЧИЦКАЯ ◽  
Ю.Ф. РОСЛЯКОВ ◽  
В.В. ЛИТВЯК ◽  
Н.В. КОМАРОВА ◽  
Е.И. КОВАЛЕНКО
Keyword(s):  
Heat Treatment ◽  
Color Change ◽  
Consumer Preferences ◽  
Heating Temperature ◽  
Wheat Bread ◽  
Time Interval ◽  
White Bread ◽  
Color Changes ◽  
Color Characteristics ◽  
Essential Contribution

В формировании потребительских предпочтений важная роль отводится внешнему виду и аромату пищевых продуктов. При выпечке хлебобулочных изделий в процессе меланоидинообразования происходит изменение цвета и появление характерного хлебного запаха. Целью работы явилось исследование ароматобразующих веществ и цветовых характеристик белого пшеничного хлеба, подверженного термической обработке. Объектами исследований служили образцы белого пшеничного хлеба, нагревание которых проводили в сушильном шкафу при температурах 90, 120, 150, 180 и 210°С с интервалом в 10 мин на протяжении 2 ч. Исследование летучих компонентов осуществляли методом газовой хроматографии с масс-селективным детектированием. Образцы фиксировали фотоаппаратом Canon EOS 750D. В результате исследований обнаружено более 120 летучих веществ, идентифицировано 76, из них 31 существенно влияет на аромат белого хлеба. В основном это карбонильные соединения и низшие жирные кислоты, а также спирты, сложные эфиры и некоторые серосодержащие соединения. Анализ изменения цветовых характеристик белого пшеничного хлеба показал, что с увеличением температуры нагревания наблюдается значительное потемнение образцов. Если при температуре 90°С происходит еще незначительное изменение цвета, даже после 2-часового воздействия, то при увеличении температуры до 180–210°С цвет образцов хлеба темнеет в первые 10 мин и в последующем меняется незначительно. Таким образом, результаты исследований показали, что температуру и длительность обжарки необходимо оптимизировать для создания наиболее востребованных потребительских свойств продукта. In the formation of consumer preferences FOR food an important role belongs to appearance and aroma. At baking as a result of the melanoid formation process the color changes and typical of bread aroma appears. The purpose of work was studying the aroma-forming substances and color characteristics of the white bread at heat treatment. The objects of the research were samples of white bread heated in a drying oven at temperatures of 90, 120, 150, 180 and 210°C with a time interval of 10 minutes for 2 hours. The volatiles were investigated by gas chromatography with mass-selective detection. The image was recorded on a Canon EOS 750D camera. As a result of the research more than 120 volatile substances were detected, it is identified 76 from which 31 make an essential contribution to aroma of white bread. Basically, these are carbonyl compounds and lower fatty acids, as well as alcohols, esters and some sulfur-containing compounds. An analysis of the change in the color characteristics of white bread showed that with an increase in the heating temperature a significant darkening of the samples is observed. At a temperature of 90°C there is still a slight color change even after a 2-hour exposure to temperature, then as the temperature increases to 180–210°C, the color of the bread samples becomes darker within the first 10 minutes and then changes insignificantly. Thus, the results of research have shown that the temperature and duration of roasting should be optimized to create the most popular consumer properties of the product.

scholarly journals Synthesis and Thermal Degradation Kinetics of Co(II), Ni(II), Cd(II), Zn(II), Pd(II), Rh(III) and Ru(III) Complexes with Methylquinolino[3,2-b]benzodiazepine

2007 ◽  
Vol 4 (2) ◽  
pp. 199-207
Author(s):  
Bennehalli Basavaraju ◽  
Halehatti S. Bhojya Naik
Keyword(s):  
Thermal Decomposition ◽  
Thermal Degradation ◽  
Elemental Analysis ◽  
Degradation Kinetics ◽  
Transition Metal Ions ◽  
Thermal Degradation Kinetics ◽  
Conductivity Measurements ◽  
Tg Studies ◽  
Kinetics Of ◽  
Kinetics And Thermodynamic

A series of new complexes formed by the interaction of a new ligand Methylquinolino[3,2-b]benzodiazepine (L) with various transition metal ions have been isolated and characterized by elemental analysis and electronic, IR, magnetic moment and conductivity measurements. Thermogravimetric (TG) studies of the complexes have been performed in order to establish the mode of their thermal degradation. The thermal degradation was found to proceed in two steps. The kinetics and thermodynamic parameters were computed from the thermal decomposition data.

scholarly journals Physical and chemical properties of Castanopsis fargesii wood after heat treatment in sand or vacuum media

BioResources ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. 5821-5837
Author(s):  
Wen-Yu Qi ◽  
Cai Liu ◽  
Xiao-Lian Wu ◽  
Ji-Qing Li ◽  
Xin Guan ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Dimensional Stability ◽  
Color Change ◽  
Lignin Content ◽  
Chemical Properties ◽  
Dry Density ◽  
Physical And Chemical Properties ◽  
Castanopsis Fargesii ◽  
Physical And Chemical ◽  
And Chemical Properties

Castanopsis fargesii is among the most prevalent hardwood species in South China. To improve the poor dimensional stability of C. fargesii wood, heat treatments were performed using vacuum or sand as the medium at four temperatures from 170 °C to 215 °C for 4 h. As a medium, vacuum or sand can create a low oxygen environment. The results showed that, as the temperature increased, the oven-dry density decreased, whereas the dimensional stability and the total color change (∆E*) increased with both media, two different changing patterns of a* and b* were observed, the lignin content increased, and the holocellulose content decreased. The oven-dry density decreased 9.4% and 25.5%, volume shrinkage ratio decreased 27.8% and 37.7%, and the ∆E* was 19.63 and 45.52, the lignin contents increased from 17.62% to 28.62% and 42.87%, and the holocellulose contents decreased from 80.49% to 69.43% and 51.04% when C. fargesii wood was heated under vacuum and with sand at 215 °C, respectively. Overall, sand heat treatment affected wood physical and chemical properties more than vacuum heat treatment. The analysis of functional groups and crystallinity also showed that there were severe changes in C. fargesii wood under sand heat treatment.

Reaction Kinetics of Paddy Husk Thermal Decomposition

1999 ◽  
Vol 121 (1) ◽  
pp. 25-30 ◽  
Author(s):  
A. K. Jain ◽  
S. K. Sharma ◽  
D. Singh
Keyword(s):  
Thermal Decomposition ◽  
Chemical Analysis ◽  
Thermal Degradation ◽  
Kinetic Parameters ◽  
Elemental Analysis ◽  
Proximate Analysis ◽  
Heating Rates ◽  
Modified Model ◽  
Renewable Source ◽  
Kinetics Of

The physical characteristics, proximate analysis, elemental analysis and chemical analysis of paddy husk, an important renewable source of energy, are reported in this paper. The kinetic parameters for the thermal degradation of paddy husk at heating rates of 10 and 100°C min−1 and under atmospheres of air and oxygennitrogen mixture (5:95) have been evaluated from experimentally obtained TGA data. The limitations of the existing TGA models are discussed, and a modified model has been used for correlation of the data.

scholarly journals Understanding thermal decomposition kinetics of flame-retardant thermoset polylactic acid

RSC Advances ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 3128-3139 ◽  
Author(s):  
Yihan Li ◽  
Zhe Qiang ◽  
Xie Chen ◽  
Jie Ren
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Thermal Degradation ◽  
Flame Retardant ◽  
Polylactic Acid ◽  
Decomposition Kinetics ◽  
Ozawa Method ◽  
Local Activation ◽  
Local Activation Energy ◽  
Kinetics Of

The Flynn–Wall–Ozawa method was applied to study the local activation energy of flame retardant thermoset PLA, and the results showed that with an increase of conversion of thermal degradation, the local activation energy was increased slowly.

scholarly journals Flame Retardant Properties and Thermal Decomposition Kinetics of Wood Treated with Boric Acid Modified Silica Sol

Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4478
Author(s):  
Qiangqiang Liu ◽  
Yubo Chai ◽  
Lin Ni ◽  
Wenhua Lyu
Keyword(s):  
Thermal Decomposition ◽  
Thermal Degradation ◽  
Boric Acid ◽  
Silica Sol ◽  
Decomposition Kinetics ◽  
Thermal Decomposition Kinetics ◽  
Poplar Wood ◽  
Modified Silica ◽  
Flame Retardant Properties ◽  
Kinetics Of

This paper presents experimental research on the flame-retardant properties and thermal decomposition kinetics of wood treated by boric-acid-modified silica sol. The poplar wood was impregnated with pure silica sol and boric-acid-modified silica sol. The results showed that modifiers can be observed in the cell wall and cell lumen. The ignition time, second peak of the heat release rate, total heat release, and mass loss of the W-Si/B were delayed obviously. The composite silicon modification had a positive impact on carbonization. Thermogravimetric analysis showed that the residual mass of W-Si/B was enhanced and the thermal degradation rate was considerably decreased. By thermal decomposition kinetics analysis, the boric acid can catalyze the thermal degradation and carbonization of poplar wood. In other words, wood treated with boric-acid-modified silica sol showed significant improvement in terms of flame retardancy, compared with wood treated with common silica sol.

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