Effect of heat treatment on shore-D hardness of some wood species

Esteves, Bruno; Şahin, Sırrı; Ayata, Ümit; Domingos, Idalina; Ferreira, José; Gürleyen, Levent

doi:10.15376/biores.16.1.1482-1495

Cited by 14 publications

(10 citation statements)

References 36 publications

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“…where Q is the energy required to break the test piece (J), and b and h are the dimensions of the test piece in the radial and tangential directions (mm). The Shore-D hardness measurements of control and frozen samples were carried out according to the ASTM D2240-15 (2021) standard with Shore-D hardness device Hardmatic HH-334, Mitutoyo, (Neuss, Germany) (Esteves et al 2021). The dimensions of Shore-D test samples were 30 mm × 20 mm × 20 mm (L × R × T).…”

Section: Methodsmentioning

confidence: 99%

Effect of freezing temperature on impact bending strength and shore-D hardness of some wood species

Özkan

2022

BioRes

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Wood is exposed to variable environmental conditions during its use. Low temperature is one of the most important environmental factors affecting the behavior of wood in use. Contrary to other mechanical properties, there are not enough studies on how the impact bending strength is affected during freezing of wood. This study evaluated the effect of various freezing temperatures (-20, -40, -78.5, and -196 °C) on the impact bending strengths of beech (Fagus orientalis Lipsky), Scotch pine (Pinus sylvestris L.), fir (Abies nordmanniana subsp. bornmulleriana), and spruce (Picea orientalis L.) wood in comparison with non-frozen wood (+20 °C). During the freezing, the impact bending strength generally increased in softwood species but decreased in hardwood. The highest drop in impact bending strength value of -30.6% was found at -196 °C for beech wood. For this reason, precautions should be taken when using beech wood at ultra-low temperatures, due to substantial decreases in impact bending strength values. The good impact bending strength properties of the softwood while frozen allows application in low temperature environments.

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Section: Methodsmentioning

confidence: 99%

Effect of freezing temperature on impact bending strength and shore-D hardness of some wood species

Özkan

2022

BioRes

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“…A betel nut was split into two parts and placed on the loading platform, with the epidermis facing upward. The Shore hardness of the betel nut was determined using an XHS Shore A hardness tester (Yingkou Material Testing Machine Co., Ltd., China) with a press pin diameter of 0.79 mm and a load of 750 g. The Shore hardness is inversely proportional to the depth of the pointer in the middle of the betel nut (Esteves et al, 2021). Testing for each sample was repeated 20 times.…”

Section: Determination Of Betel Nut Shore a Hardnessmentioning

confidence: 99%

Effect of Steam Explosion on the Morphological, Textural and Chemical Composition Characteristics of Betel Nut

Yang

Chen

et al. 2023

Preprint

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To reduce the adverse physical effects on the oral mucosa caused by excessive hardness of betel nut fibres, steam explosion was used to soften betel nuts. The effect of 3 operating parameters (pressure holding time, explosion pressure and initial moisture content) on the morphology, texture and chemical composition of the betel nuts was investigated. The fibre hardness and Shore hardness decreased by 56.17%-89.28% and 7.03%-34.29%, respectively, and the transverse tensile strength and fibre tensile strength also decreased by up to 60.72% and 24.62%, respectively. Moreover, the coefficient of friction and moisture content increased. After steam explosion, the betel nut increased in transverse diameter, became darker and more yellow‒red in colour, and showed a damaged microstructure. The contents of lignin, hemicellulose, free phenol, bound phenol and alkaloids decreased after steam treatment, with total phenols and alkaloids decreasing from 44.07 mg(GAE)/g and 7.84 mg/g to 30.61 mg(GAE)/g and 6.50 mg/g, respectively, after the A-50 s treatment condition. A slight increase in cellulose was observed when steam explosion conditions exceeded 80 s or 0.75 MPa. The steam explosion increased the quantity of phenols, alkaloids and soluble solids released from the betel nut under the same simulated release conditions. The research also showed that the explosion efficiency was positively correlated with the pressure holding time and explosion pressure, while the initial moisture content was reduced the explosion efficiency. Therefore, steam explosion is an effective pretreatment approach to soften betel nut and facilitate healthy development of the betel nut industry.

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“…The Shore-D hardness tester (LX-D, Xi Jing, Wuxi, China) was used to measure the hardness of wood according to the ASTM D2240 (2010) standard [18,19]. A 5 kg load was used as the weight to determine the hardness.…”

Section: Mechanical Properties Testmentioning

confidence: 99%

Effects of Low-Energy-Density Microwave Treatment on Graphene/Polyvinyl Alcohol-Modified Poplar Veneer

2022

Forests

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The combination of natural wood and graphene can provide a new type of material with excellent mechanical properties and thermal conductivity. However, it is difficult for graphene to uniformly penetrate the wood due to the anisotropy of natural wood and the agglomeration of graphene. In this work, poplar veneer was treated with low-energy-density microwave to expand the entry pathways for the graphene steering liquid. The porosity, weight percent gain, and chromatic aberration were used to examine the impact of the microwave time and power. We tested the mechanical properties, thermal conductivity of the graphene/polyvinyl alcohol-modified poplar veneer to evaluate its properties. At the same time, SEM, XRD, and FT-IR were used to characterize its physical and chemical structure. The results showed that low-energy-density microwave treatment increased the weight percentage gain (WPG) and porosity without affecting the mechanical properties of the poplar veneer. The graphene-modified poplar veneer with the optimal overall performance was obtained by microwave treatment at 100% microwave power for 50 s. Indeed, the micro-characterization also revealed that the microwave treatment mostly attacked the wood rays but had little effect on the materialized structure. Therefore, low-energy-density microwave treatment could be an energy-saving and efficient way to improve graphene-impregnated veneers.

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Effect of heat treatment on shore-D hardness of some wood species

Cited by 14 publications

References 36 publications

Effect of freezing temperature on impact bending strength and shore-D hardness of some wood species

Effect of freezing temperature on impact bending strength and shore-D hardness of some wood species

Effect of Steam Explosion on the Morphological, Textural and Chemical Composition Characteristics of Betel Nut

Effects of Low-Energy-Density Microwave Treatment on Graphene/Polyvinyl Alcohol-Modified Poplar Veneer

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