Einfluß von Holzfeuchtigkeit und Rohdichte auf die Schlagbiegefestigkeit von Kiefern-, Fichten- und Buchenholz/ Influence of moisture content and density on impact bending strength of spruce, pine and beech wood/ L’influence de l’humidité et de la densité sur la résistance à la flexion au choc du bois de pin, d’ épicéa et de hêtre

1970 ◽  
Vol 12 (9) ◽  
pp. 313-316
Author(s):  
Arno Burmester
Keyword(s):  
Moisture Content ◽  
Bending Strength ◽  
Beech Wood ◽  
Du Bois ◽  
Impact Bending

Mechanical properties of Ficus vallis-choudae (Delile), a lesser utilized species in Nigeria

BioResources ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 6550-6560
Author(s):  
Lawrence Aguda ◽  
Babatunde Ajayi ◽  
Sylvester Areghan ◽  
Yetunde Olayiwola ◽  
Aina Kehinde ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Moisture Content ◽  
Modulus Of Elasticity ◽  
Bending Strength ◽  
High Strength ◽  
Strength Properties ◽  
Modulus Of Rupture ◽  
Impact Bending ◽  
Timber Market

Declining availability of the prime economic species in the Nigerian timber market has led to the introduction of Lesser-Used Species (LUS) as alternatives. Their acceptability demands information on the technical properties of their wood. The aim of this study was to investigate the mechanical properties of Ficus vallis-choudae to determine its potential for timber. Three mature Ficus vallis-choudae trees were selected and harvested from a free forest area in Ibadan, Oyo State, Nigeria. Samples were collected from the base (10%), middle (50%), and top (90%) along the sampling heights of each tree, which was further partitioned into innerwood, centrewood, and outerwood across the sampling radial position. Investigations were carried out to determine the age, density, moisture content, impact strength, modulus of elasticity, modulus of rupture, compressive strength parallel-to-grain, and shear strength parallel-to-grain. The mean impact bending strength, modulus of rupture, modulus of elasticity, maximum shear strength parallel-to-grain, and maximum compression strength parallel-to-grain for Ficus vallis-choudae at 12% moisture content were 20.4 N/mm2, 85.8 N/mm2, 709 N/mm2, 10.7 N/mm2, and 33.6 N/mm2, respectively. The study found the species to be dense with high strength properties in comparison with well-known timbers used for constructional purposes.

scholarly journals Effects of Nanosilver Impregnation on Impact Bending Strength of Ice-Blasted Beech and Poplar Woods

2018 ◽  
Vol 15 (7) ◽  
pp. 481-489 ◽  
Author(s):  
Ayoub ESMAILPOUR ◽  
Mohammad Sadegh TAHER TOLOU DEL ◽  
Hamid Reza TAGHIYARI ◽  
Adrian Cheng Yong CHOO ◽  
Hassan SIAHPOSHT
Keyword(s):  
Impact Strength ◽  
Bending Strength ◽  
Size Range ◽  
Beech Wood ◽  
Solid Wood ◽  
Strength Increase ◽  
Environment Effects ◽  
Negative Effect ◽  
Impact Bending ◽  
The Impact

Ice-blasting (frozen CO2 at minus 78.5 ºC) is one of the modern methods of cleaning for industrial purposes without any contamination or hazard to the environment. Effects of ice-blasting were studied here on the basis of normal solid wood as well as nanosilver-impregnated Populus nigra and Fagus orientalis. The size range of silver nanoparticles was 20 - 90 nm. Specimens were free from any knots,  splits, rot, or other visual defects. Results showed that ice-blasting made impact strength decrease in beech by 8.4 %; however, an insignificant increase of 0.8 % was observed in poplar. Impregnating the specimens with a nanosilver suspension before ice-blasting made impact strength increase by 25.8 % in poplar; it also mitigated the impact loss in beech (5.2 % in comparison to control specimens). It can be concluded that the negative effect of ice-blast treatment is less in lower-density poplar wood; also, impregnation with nanosilver can even increase its impact strength. In higher-density beech wood, however, the impregnation can mitigate the significant negative effect of the ice-blast treatment on impact bending strength.

scholarly journals Impact Bending Strength and Brinell Hardness of Densified Hardwoods

BioResources ◽  
2016 ◽  
Vol 11 (4) ◽  
Author(s):  
Miroslav Gašparík ◽  
Milan Gaff ◽  
Lenka Šafaříková ◽  
Carlos Rodriguez Vallejo ◽  
Tomáš Svoboda
Keyword(s):  
Bending Strength ◽  
Brinell Hardness ◽  
Impact Bending

Glass Transition Temperature, Mechanical Properties of Rice and their Relationships with Milling Quality

2012 ◽  
Vol 8 (3) ◽  
Author(s):  
Kobra Tajaddodi Talab ◽  
Mohd. Nordin Ibrahim ◽  
Sergey Spotar ◽  
Rosnita A. Talib ◽  
Kharidah Muhammad
Keyword(s):  
Mechanical Properties ◽  
Glass Transition ◽  
Moisture Content ◽  
Bending Strength ◽  
Bending Test ◽  
Transition Line ◽  
Transition Temperatures ◽  
Drying Process ◽  
Glass Transition Temperatures ◽  
Grain Moisture

Abstract Glass transition temperatures (Tg) of MR219 rice variety were measured by differential scanning calorimeter (DSC). State diagram was developed and used to evaluate drying process in this study. Glass transition temperatures range of 9.65- 61.79°C were observed for gains with moisture content of 26.8 – 7.4% (w.b.). For mechanical properties and milling test, statistical analysis was performed by using a two factor experiment in completely randomized design (CRD). Two selected factors were drying temperatures at 5 levels (40, 45, 50, 55, and 60°C) and final moisture content (FMC) at 4 levels (10-10.5, 11-11.5, 12-12.5 and 13-13.5%). Three–point bending test was applied to measure the mechanical properties of rice kernel. Generally, bending strength, apparent modulus of elasticity and fracture energy of brown rice kernel increased with decreasing the grain moisture content. Maximum bending strength was 35.69 and 33.64 MPa for 55, and 60°C, respectively. All samples that were dried at 55 and 60°C experienced to go through the glass transition line after reaching their temperature to the room temperature at the end of drying process. The effect of drying temperature, paddy FMC and their interactions on whole kernel percentage (WKP) and mechanical properties were significant (α = 0.05). An inverse relationship was observed between WKP and the percentage of strong kernels for all treatments.

CORRELATION DEPENDENCES OF THE BENDING STRENGTH OF POLYMER COMPOSITE MATERIALS MODIFIED IN A MICROWAVE ELECTROMAGNETIC FIELD ON THE MOISTURE CONTENT DURING EXPOSURE IN FULL-SCALE CONDITIONS

2021 ◽  
pp. 3-9
Author(s):  
I. V. Zlobina ◽  
I. S. Katsuba
Keyword(s):  
Electromagnetic Field ◽  
Composite Materials ◽  
Carbon Fiber ◽  
Moisture Content ◽  
Bending Strength ◽  
Climatic Factors ◽  
Experimental Studies ◽  
Three Point Bending ◽  
Treated Carbon ◽  
Control Samples

Experimental studies of the influence of external climatic factors, taking into account exposure, on the change in the bending strength of control and microwave – treated carbon and fiberglass samples in the cured state were performed. An increase in the limit stresses of three – point bending of experimental carbon fiber samples compared to the control ones was found by 7…12 %, and fiberglassby 4…7 %. It is shown that with an increase in exposure to 14 months, the strength of control samples of carbon and fiberglass decreases by an average of 10 %. At the same time, the strength of the prototypes is reduced only by 4.4 %. With an increase in the moisture content of both control and experimental samples, a decrease in their strength is observed. In this case, the linear correlation is average (from– 0.44 to – 0.615). It is established that for experimental samples, the influence of the amount of absorbed moisture on the strength is manifested to a much lesser extent. For carbon fiber, the reduction is 16.6 %, for fiberglass – 12 %.

scholarly journals The Impact of Paraffin-Thermal Modification of Beech Wood on Its Biological, Physical and Mechanical Properties

Forests ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 1102 ◽  
Author(s):  
Ladislav Reinprecht ◽  
Miroslav Repák
Keyword(s):  
Mechanical Properties ◽  
Bending Strength ◽  
Beech Wood ◽  
Physical And Mechanical Properties ◽  
Brown Rot ◽  
European Beech ◽  
White Rot ◽  
White Rot Fungus ◽  
Poria Placenta ◽  
The Impact

The European beech (Fagus sylvatica L.) wood was thermally modified in the presence of paraffin at the temperatures of 190 or 210 °C for 1, 2, 3 or 4 h. A significant increase in its resistance to the brown-rot fungus Poria placenta (by 71.4%–98.4%) and the white-rot fungus Trametes versicolor (by 50.1%–99.5%) was observed as a result of all modification modes. However, an increase in the resistance of beech wood surfaces to the mold Aspergillus niger was achieved only under more severe modification regimes taking 4 h at 190 or 210 °C. Water resistance of paraffin-thermally modified beech wood improved—soaking reduced by 30.2%–35.8% and volume swelling by 26.8%–62.9% after 336 h of exposure in water. On the contrary, its mechanical properties worsened—impact bending strength decreased by 17.8%–48.3% and Brinell hardness by 2.4%–63.9%.

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