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.

Research of the Relationship between Hemp Fiber Density and its Chemical Composition

2011 ◽  
Vol 332-334 ◽  
pp. 152-155
Author(s):  
Ying Chao Ji ◽  
Jin Xing Ju ◽  
Yu Jia Liang
Keyword(s):  
Chemical Composition ◽  
Lignin Content ◽  
Chemical Compositions ◽  
Cellulose Content ◽  
Fiber Density ◽  
Hemp Fiber ◽  
Pectin Content ◽  
Density Values ◽  
The Relationship ◽  
Range Of Variation

Currently available data on density of hemp are all specific values, and their differences are obvious, which could bring trouble to the related products’ development and actual production. Therefore, provide accurate density values conducive to better achieve the development and use of hemp fiber related products. This paper mainly analysis the relevancy between hemp bast fibers’ chemical compositions and its density after degumming, and draw a conclusion that the density of hemp fiber is not a fixed value but a range of variation. The density will be changed when chemical composition contents in different hemp fiber are different. Which chemical composition that affected the density most is cellulose content, followed by pectin content, and than, the lignin content and hemi cellulose content.

Permanent Mold Casting Practice and Microstructure and Mechanical Properties of Thin-Sectioned ADI Casting

2007 ◽  
Vol 26-28 ◽  
pp. 531-534
Author(s):  
B.M. Moon ◽  
Bong Hwan Kim ◽  
Je Sik Shin ◽  
Sang Mok Lee
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Ductile Cast Iron ◽  
Treatment Temperature ◽  
Chemical Compositions ◽  
Permanent Mold ◽  
Permanent Mold Casting ◽  
Treatment Practice ◽  
Mold Casting ◽  
Si Content

For thin-walled casting development of austempered ductile iron (ADI), permanent mold casting and accompanied heat treatment practice were systematically investigated to suppress and/or remove chill defects of ductile cast iron (DCI) with various thickness of 2 to 9 mm and to ensure mechanical properties of the final ADI casting. Si content was increased up to 3.8% to reduce the chill formation tendency under a high cooling rate. The residual Mg content remarkably affected the nodule count, while the nodule size and spherodization were proven to have weak relationships. Austenitizing process followed by austempering was very sensitive to chemical compositions (Si and Sn) and heat treatment temperature. As a practical application, the steel bar coupler for a structural frame was tried to produce without subsequent machining.

scholarly journals Self-Toughening and Self-Enhancement Poly(arylene ether nitrile) with Low Dielectric Constant by Solid Crosslinking Reaction

Polymers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1403 ◽  
Author(s):  
Lifen Tong ◽  
Xiting Lei ◽  
Guangyao Yang ◽  
Xiaobo Liu
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Dielectric Constant ◽  
Thermal Properties ◽  
Heat Treatment Temperature ◽  
Treatment Temperature ◽  
Cross Linking ◽  
Hydroxyl Groups ◽  
Crosslinking Reaction ◽  
Arylene Ether

A novel poly(arylene ether nitrile) terminated with hydroxyl groups (PEN–OH) was synthesized successfully. The effects of heat-treatment temperature on the thermal properties, mechanical properties, and dielectric properties of the PEN–OH films were studied in detail. Due to the cross-linking reaction occurring, at high temperature, among the nitrile groups on the side of the PEN–OH main chain to form a structurally stable triazine ring, the structure of materials changes from a linear structure to a bulk structure. Thus, the thermal properties and mechanical properties were improved. In addition, the occurrence of cross-linking reactions can reduce the polar groups in the material, leading to the decrease of dielectric constant. As the heat-treatment temperature increased, the glass-transition temperature increased from 180.6 °C to 203.6 °C, and the dielectric constant decreased from 3.4 to 2.8 at 1 MHz. Proper temperature heat-treatment could improve the tensile strength, as well as the elongation, at the break of the PEN–OH films. Moreover, because of the excellent adhesive property of PEN–OH to copper foil, a double-layer flexible copper clad laminate (FCCL) without any adhesives based on PEN–OH was prepared by a simple hot-press method, which possessed high peel strength with 1.01 N/mm. Therefore, the PEN–OH has potential applications in the electronic field.

scholarly journals Calorific Power Improvement of Wood by Heat Treatment and Its Relation to Chemical Composition

Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5322
Author(s):  
Idalina Domingos ◽  
Umit Ayata ◽  
José Ferreira ◽  
Luisa Cruz-Lopes ◽  
Ali Sen ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Chemical Composition ◽  
Lignin Content ◽  
Treated Wood ◽  
Untreated Wood ◽  
High Heating Value ◽  
Heat Treated ◽  
Positive Linear Correlation ◽  
Total Extractives ◽  
Calorific Power

Chemical composition influences the calorific power of wood, mainly due to the calorific power of structural compounds and extractives. Heat treatment changes the chemical composition of treated wood. This work studies the relationship between chemical composition and calorific power improvement by heat treatment. Samples were heat-treated by the ThermoWood process ® for 1 h and 2 h. High heating value (HHV) and chemical composition; lignin, cellulose, hemicelluloses and extractives in dichloromethane, ethanol, and water were determined. The HHV of untreated wood ranged between 18.54–19.92 MJ/kg and increased with heat treatment for all the tested species. A positive linear correlation was found between HHV and Klason lignin (R2 = 0.60). A negative trend was observed for holocellulose, cellulose, and hemicelluloses content against HHV, but with low determination coefficients for linear regression. The best adjust for polysaccharides was found for hemicelluloses content. A positive correlation could be found for dichloromethane extractives (R2 = 0.04). The same was obtained in relation to ethanol extractives with R2 = 0.20. For water and total extractives, no clear positive or negative trends could be achieved. The results showed that the HHV of wood increased with heat treatment and that this increase was mainly due to the increase in lignin content.

scholarly journals Research on NDT Technology in Inference of Steel Member Strength Based on Macro/Micro Model

2017 ◽  
Vol 2017 ◽  
pp. 1-11
Author(s):  
Beidou Ding ◽  
Naiqiang Xiao ◽  
Shuxun Zhang ◽  
Yong Wang
Keyword(s):  
Grain Size ◽  
Regression Analysis ◽  
Chemical Composition ◽  
Carbon Steel ◽  
Quantitative Relationship ◽  
Engineering Practice ◽  
Composition Analysis ◽  
Chemical Compositions ◽  
Steel Strength ◽  
Tension Properties

In consideration of correlations among hardness, chemical composition, grain size, and strength of carbon steel, a new nondestructive testing technology (NDT) of inferring the carbon steel strength was explored. First, the hardness test, chemical composition analysis, and metallographic analysis of 162 low-carbon steel samples were conducted. Second, the following works were carried out: (1) quantitative relationship between steel Leeb hardness and carbon steel strength was studied on the basis of regression analysis of experimental data; (2) influences of chemical composition and grain size on tension properties of carbon steel were analyzed on the basis of stepwise regression analysis, and quantitative relationship between conventional compositions and grain size with steel strength was obtained; (3) according to the macro and/or micro factors such as hardness, chemical compositions, and grain size of carbon steel, the fitting formula of steel strength was established based on MLR (multiple linear regressions) method. The above relationships and fitting formula based on MLR method could be used to estimate the steel strength with no damage to the structure in engineering practice.

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 Investigation of the Resistance and Sensitivity of Infectious Bacteria to Dendrostellera lessertii and Chemical Composition Analysis

2021 ◽  
Vol 6 (1) ◽  
pp. 30-36
Author(s):  
Mostafa Alamholo
Keyword(s):  
Chemical Composition ◽  
Methanolic Extract ◽  
Antibacterial Properties ◽  
Gas Chromatography Mass Spectrometry ◽  
Total Phenolic ◽  
Dilution Method ◽  
Composition Analysis ◽  
Chemical Compositions ◽  
Root Extract ◽  
Chemical Composition Analysis

Introduction: Herbal plants are important sources for finding new and rare products of medicinal value for drug development. The present research aimed to investigate the antibacterial properties of Dendrostellera lessertii against infectious bacteria and analyze its chemical composition. Methods: The different organs comprising root, stem, and leaf of D. lessertii from Lorestan province, Iran, were tested. Antibacterial activity was assessed using the agar well-diffusion assay. The total phenolic content (TPC) and total flavonoid content (TFC) were assessed by the Folin Ciocalteu and aluminum chloride methods, respectively. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were tested by the serial dilution method, and chemical compositions were analyzed by gas chromatography-mass spectrometry (GC/MS). Results: The chemical composition analysis showed the dominance of bergamotol (10.62%) and bis (2-ethylhexyl) phthalate (7.49%) in the stem extract. However, phytol (12.64%) and E-11-hexadecenal (12.53%) were major constituents in the root extract. Furthermore, major constituents in the leaf extract were phytol (19.658%) and hexadecanoic acid (7.151%). The methanolic extract of root exhibited the highest TPC as 109.1±2.2 mgGA/g and TFC as 2.1±0.33 mgQ/g. The root methanolic extract demonstrated a MIC of 3.125 mg/mL against Enterococcus faecalis. Accordingly, the highest sensitivity and resistance were observed on E. faecalis and Pseudomonas aeruginosa, respectively. Conclusion: Dendrostellera lessertii extract is suggested as a source for antimicrobial drugs, especially to treat bacterial infections.

scholarly journals The Influence of the Precipitation Heat Treatment Temperature on the Metallurgical, Microstructure, Thermal Properties, and Microhardness of an Alpha Brass

2018 ◽  
Vol 09 (04) ◽  
pp. 440-454 ◽  
Author(s):  
Ignacio Rojas-Rodríguez ◽  
Alberto Lara-Guevara ◽  
Mauricio Salazar-Sicacha ◽  
Julio Cesar Mosquera-Mosquera ◽  
Minerva Robles-Agudo ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Thermal Properties ◽  
Heat Treatment Temperature ◽  
Treatment Temperature ◽  
Alpha Brass ◽  
Precipitation Heat ◽  
Metallurgical Microstructure

Tribological Behavior of Electroless Ni-P, Ni-P-W and Ni-P-Cu Coatings

2017 ◽  
Vol 5 (1) ◽  
pp. 1-15 ◽  
Author(s):  
Prasanta Sahoo ◽  
Supriyo Roy
Keyword(s):  
Heat Treatment ◽  
Heat Treatment Temperature ◽  
Tribological Behavior ◽  
Treatment Temperature ◽  
Chemical Compositions ◽  
Heat Treated ◽  
Tungsten Concentration ◽  
The Comparative Study ◽  
Main Effects ◽  
Electroless Ni

The present paper considers the comparative study of tribological characteristics of various electroless alloy coatings viz. Ni-P, Ni-P-W and Ni-P-Cu. The tribological behavior of these coatings depends on various parameters like load, speed, lubricant, chemical compositions and heat treatment temperature to a great extent. One of the main effects of heat treatment on these coatings is phosphide precipitation, which makes them suitable for anti-wear applications. The property of binary Ni-P can be further improved by depositing third particles electrolessly. The phase structure of the coatings depends on the amount of phosphorous and heat treatment temperature. The tribological behavior of heat treated samples reveals that Ni-P-W deposit shows higher coefficient of friction and lowest wear among these three types coatings. Very high tungsten concentration retard the phosphide precipitation, thus low concentration of tungsten and low heat treatment temperature produce better coating. In case of Ni-P-Cu, medium concentration of copper and medium heat treatment temperature produces better coating.

The Discrepancy between Gross Features and Chemical Compositions in Gallbladder Stone: A Descriptive Single Center Study in the United Arab Emirates

2021 ◽  
Vol 02 ◽  
Author(s):  
Byung Hyo Cha ◽  
Min Jung Park ◽  
Joo Yeong Baeg ◽  
Sunpyo Lee ◽  
Young Joon Ahn ◽  
...  
Keyword(s):  
Chemical Composition ◽  
United Arab Emirates ◽  
Gastrointestinal Disease ◽  
Chemical Constituents ◽  
Composition Analysis ◽  
Cholesterol Stone ◽  
Chemical Compositions ◽  
Gallbladder Stone ◽  
Tertiary Referral Hospital ◽  
Primary Indication

Background and Study Aim: Gallbladder stone (GBS) is a common gastrointestinal disease that is the primary indication for cholecystectomy. The present study was conducted to describe the chemical composition of gallstones in a tertiary referral hospital in the United Arab Emirates. Materials and Methods: Patients diagnosed with GBS and who underwent cholecystectomy due to symptomatic GBS and cholecystitis in Sheikh Khalifa Specialty Hospital were enrolled in this study. After cholecystectomy, all stone specimens were classified according to their gross findings into 4 groups, namely black pigmented stones (BLPS), brown pigmented stones (BRPS), mixed cholesterol stones, and cholesterol stones (CLS). Quantitative analysis using Fourier transform infrared spectroscopy was then performed to define the stones’ chemical constituents. They were reclassified into two groups as CLS (cholesterol ≥ 60%) and pigmented stones (PGS, cholesterol ≤ 59%) based on gallstone composition analysis. Results: A total of 237 stones were divided into four groups based on their gross findings; cholesterol stones (32.0%), mixed cholesterol (29.2%), black pigmented (26.4%), and brown pigmented (12.3%). After chemical composition analysis, they were resorted into the two following groups according to their cholesterol proportions: pigmented (28.3%) and cholesterol (71.7%). There were significant statistical mean age differences between the pigmented and cholesterol stone groups (58.5±19.8 vs. 34.4±11.0, p < 0.01). Conclusion: This descriptive study showed the hospital-based clinical incidence of GBS and suggested that there might be a discrepancy in stone classification based on gross findings and chemical compositions. Moreover, pigmented stones are more likely to be present in older patients than cholesterol stones.

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