Effects of cell size and cell wall thickness variations on the strength of closed-cell foams

2017 ◽  
Vol 120 ◽  
pp. 220-240 ◽  
Author(s):  
Youming Chen ◽  
Raj Das ◽  
Mark Battley
Keyword(s):  
Cell Wall ◽  
Cell Size ◽  
Wall Thickness ◽  
Cell Wall Thickness ◽  
Closed Cell ◽  
Thickness Variations

Characterization of microstructures of SAN foam core using micro-computed tomography

2021 ◽  
pp. 026248932110068
Author(s):  
Youming Chen ◽  
Raj Das ◽  
Hui Wang ◽  
Mark Battley
Keyword(s):  
Cell Wall ◽  
Cell Size ◽  
Wall Thickness ◽  
Strain Localization ◽  
Cell Wall Thickness ◽  
Micro Computed Tomography ◽  
Average Cell Size ◽  
Average Cell ◽  
3D Images ◽  
Compressive Tests

In this study, the microstructure of a SAN foam was imaged using a micro-CT scanner. Through image processing and analysis, variations in density, cell wall thickness and cell size in the foam were quantitatively explored. It is found that cells in the foam are not elongated in the thickness (or rise) direction of foam sheets, but rather equiaxed. Cell walls in the foam are significantly straight. Density, cell size and cell wall thickness all vary along the thickness direction of foam sheets. The low density in the vicinity of one face of foam sheets leads to low compressive stiffness and strength, resulting in the strain localization observed in our previous compressive tests. For M80, large open cells on the top face of foam sheets are likely to buckle in compressive tests, therefore being another potential contributor to the strain localization as well. The average cell wall thickness measured from 2D slice images is around 1.4 times that measured from 3D images, and the average cell size measured from 2D slice images is about 13.8% smaller than that measured from 3D images. The dispersions of cell wall thickness measured from 2D slice images are 1.16–1.20 times those measured from 3D images. The dispersions of cell size measured from 2D slice images are 1.12–1.36 times those measured from 3D images.

Effects of cell size vs. cell-wall thickness gradients on compressive behavior of additively manufactured foams

2020 ◽  
Vol 199 ◽  
pp. 108339 ◽  
Author(s):  
Yu Duan ◽  
Yi Ding ◽  
Zhiyong Liu ◽  
Naidan Hou ◽  
Xianhang Zhao ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cell Size ◽  
Wall Thickness ◽  
Cell Wall Thickness ◽  
Compressive Behavior

scholarly journals Nitrogen deprivation of microalgae: effect on cell size, cell wall thickness, cell strength, and resistance to mechanical disruption

2016 ◽  
Vol 43 (12) ◽  
pp. 1671-1680 ◽  
Author(s):  
Benjamin H. J. Yap ◽  
Simon A. Crawford ◽  
Raymond R. Dagastine ◽  
Peter J. Scales ◽  
Gregory J. O. Martin
Keyword(s):  
Cell Wall ◽  
Cell Size ◽  
Wall Thickness ◽  
Cell Wall Thickness ◽  
Nitrogen Deprivation ◽  
Mechanical Disruption ◽  
Cell Strength

scholarly journals Anatomical Features Facilitating Supercooling of the Flower within the Dormant Peach Flower Bud

1995 ◽  
Vol 120 (5) ◽  
pp. 814-822 ◽  
Author(s):  
H.A. Quamme ◽  
Wei Ai Su ◽  
L.J. Veto
Keyword(s):  
Cell Wall ◽  
Cell Size ◽  
Wall Thickness ◽  
Prunus Persica ◽  
Cell Wall Thickness ◽  
Freezing Injury ◽  
Flower Bud ◽  
A Cell ◽  
Temperature Scanning ◽  
Cell Zone

Excision of the flower from the peach [Prunus persica (L.) Batsch.] flower bud raised the 50% injury temperature of flowers (cooled at 1C/hour) from -18 and -20C to -10 and -13C on two test dates, 26 Feb. 1988 and 5 Dec. 1990, respectively. Ice inoculation of the excised flowers at -3C further raised the 50% injury temperature to -7 and -8C for the two dates, respectively. These observations suggest that supercooling is a true mechanism for avoiding freezing injury. Low temperature scanning electron microscopy of freeze fractured cells verified that the flower froze intracellularly, whereas the subtending tissue froze extracellularly. Ice inoculation of the flower and the flower bud axis from which the scales were removed demonstrated that a barrier to ice propagation (effective to -11C) from the flower bud axis to the flower was present. This barrier may involve the provascular strands and a cell zone at the flower base (BZ) that were devoid of intercellular spaces. These tissues also had smaller cells, smaller vacuoles, greater ratio of cell wall thickness to cell size than tissue just below the BZ, which may result in greater cell rigidity and restriction of extracellular freezing. The cells outside the provascular strands at the base of the flower were also lacking in intercellular space, were smaller in size, and had a higher ratio of cell wall thickness to cell size compared to cells near the base of the scales. In the intact flower buds in which the flowers supercool below -11C, the presence of the first and second scales was important to full expression of supercooling because their removal raised the supercooling point, whereas the removal of lower scales did not. Sequestration of ice by the first two subtending scales during the early stages of freezing may be important to the creation of a dry region at the flower base that prevents ice propagation into the flower at temperatures below -11C.

Properties of Gliricidia Wood (Gliricidia sepium) lntercropped with Cocoa (Theobroma cocoa) in Malaysia

2014 ◽  
Vol 11 (1) ◽  
pp. 51
Author(s):  
Mohd Helmy Ibrahim ◽  
Mohd Nazip Suratman ◽  
Razali Abd Kader
Keyword(s):  
Cell Wall ◽  
Specific Gravity ◽  
Moisture Content ◽  
Wall Thickness ◽  
Age Groups ◽  
Gliricidia Sepium ◽  
Cell Wall Thickness ◽  
Tree Age ◽  
Lumen Diameter ◽  
Significant Difference

Trees planted from agroforestry practices can become valuable resources in meeting the wood requirements of many nations. Gliricidia sepium is an exotic species introduced to the agricultural sector in Malaysia mainly for providing shade for cocoa and coffee plantations. This study investigates its wood physical properties (specific gravity and moisture content) and fibre morphology (length, lumen diameter and cell wall thickness) of G. sepium at three intervals according to age groups ( three, five and seven years of ages). Specific gravity (0.72) was significantly higher at seven years ofage as compared to five (0.41) and three (0.35) years age group with a mean of 0.43 (p<0.05). Mean moisture content was 58.3% with no significant difference existing between the tree age groups. Fibre diameter (22.4 mm) was significantly lower (p<0.05) for the trees which were three years of age when compared to five and seven years age groups (26.6 mm and 24. 7 mm), respectively. Means of fibre length, lumen diameter and cell wall thickness were 0.83 mm, 18.3 mm, and 6.2 mm, respectively, with no significant differences detected between trees in all age groups. Further calculation on the coefficient of suppleness and runkel ratio suggest that wood from G.sepium may have the potential for insulation board manufacturing and paper making. However, future studies should experiment the utilisation of this species for these products to determine its full potential.

Summer temperature in northeastern Siberia since 1642 reconstructed from tracheid dimensions and cell numbers of Larix cajanderi

2003 ◽  
Vol 33 (10) ◽  
pp. 1905-1914 ◽  
Author(s):  
Irina P Panyushkina ◽  
Malcolm K Hughes ◽  
Eugene A Vaganov ◽  
Martin AR Munro
Keyword(s):  
Cell Wall ◽  
Wall Thickness ◽  
Cell Number ◽  
Cell Wall Thickness ◽  
Cell Dimension ◽  
Cell Numbers ◽  
Age Related ◽  
Cambial Age ◽  
Northeastern Siberia ◽  
Larix Cajanderi

We reconstructed air temperature for two periods in the growth season from cell dimension and cell number variability in cross-dated tree rings of Larix cajanderi Mayr. from northeastern Siberia. Thirteen tree-ring chronologies based on cell size, cell wall thickness, and cell number were developed for AD 1642–1993. No clear evidence was found of an age-related trend in cell dimensions in the sampled materials, but cell numbers were correlated with cambial age. The chronologies contain strong temperature signals associated with the timing of xylem growth. We obtained reliable reconstructions of mean June temperature from the total cell number and July–September temperature from the cell wall thickness of latewood. June temperature and July–September temperature covaried for most of the period from AD 1642 to AD 1978. After that time, June temperature became cooler relative to July–September temperature. This difference caused disproportional changes in earlywood tracheids because of the late start of growth and cool conditions in June followed by warming during the rest of the season. The identification of this unusual recent change has shown that intraseasonal resolution may be achieved by cell dimension and cell number chronologies.

Sign in / Sign up

Export Citation Format

Share Document