scholarly journals Russet Susceptibility in Apple Is Associated with Skin Cells that Are Larger, More Variable in Size, and of Reduced Fracture Strain

Plants ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1118
Author(s):  
Bishnu P. Khanal ◽  
Thi Lieu Le ◽  
Yiru Si ◽  
Moritz Knoche
Keyword(s):  
Fruit Development ◽  
Fracture Strain ◽  
Indirect Evidence ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Growth Stages ◽  
Skin Cells ◽  
Surface Disorder ◽  
Apple Cultivars ◽  
Tangential Surface

Russeting is an economically important surface disorder in apple (Malus × domestica Borkh). Indirect evidence suggests an irregular skin structure may be the cause of the phenomenon. The objective of this study was to characterize epidermal and hypodermal cell morphology and the mechanical properties of the skins of apple cultivars of differing russet susceptibility. Dimensions of epidermal and hypodermal cells were determined using microscopy. Stiffness (S), maximum force (Fmax), and maximum strain (εmax) at failure were quantified using uniaxial tensile tests of skin strips. Particularly during early fruit development, epidermal cells (EC) and hypodermal cells (HC) in russet non-susceptible cultivars occurred in greater numbers per unit area than in russet-susceptible ones. The EC and HC were lower in height, shorter in length, and of reduced tangential surface area. There were little differences in S or Fmax between non-susceptible and susceptible cultivars. However, the εmax were higher for the skins of non-susceptible cultivars, than for those of susceptible ones. This difference was larger for the young than for the later growth stages. It is concluded that russet-susceptible cultivars generally have larger cells and a wider distribution of cell sizes for both EC and HC. These result in decreased εmax for the skin during early fruit development when russet susceptibility is high. This increases the chances of skin failures which is known to trigger russeting.

Effect of Prestrain on Tensile and Fracture Toughness Properties of Line Pipes

2002 ◽  
Author(s):  
Naoki Fukuda ◽  
Naoto Hagiwara ◽  
Tomoki Masuda
Keyword(s):  
Base Metal ◽  
Bauschinger Effect ◽  
Fracture Strain ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Crack Tip Opening Displacement ◽  
Opening Displacement ◽  
Line Pipe ◽  
Critical Fracture ◽  
Crack Tip Opening

To investigate the mechanical properties of pipeline subjected to plastic deformation, tensile tests and crack-tip-opening displacement (CTOD) tests were conducted on X60, X65 and X80 line pipe steels with uniaxial tensile or compressive prestrain, εpr. The tensile tests revealed that the Bauschinger effect and work hardening were dependent on the yield-to-tensile ratio (Y/T) of the steels; the change in yield stress due to prestrain linearly depended on the Y/T of the base metal. A critical CTOD for crack initiation decreased with increasing |εpr|.Compressive prestrain had a larger effect on the reduction of the critical CTOD than tensile prestrain. The reduction in the critical CTOD due to tensile prestrain was predictable with a simplified theoretical model employing a critical fracture strain of the base metal.

Influences of Specimen Size and Temperature on Viscoelastic Tensile Properties of SU-8 Photoresist Films

2016 ◽  
Vol 138 (2) ◽  
Author(s):  
Takahiro Namazu ◽  
Kenichi Takio ◽  
Shozo Inoue
Keyword(s):  
Stress Relaxation ◽  
Test Temperature ◽  
Fracture Strain ◽  
Thick Films ◽  
Tensile Tests ◽  
Specimen Size ◽  
Uniaxial Tensile ◽  
Apparent Thickness ◽  
The Mean ◽  
Apparent Activation Energies

In this paper, the influences of specimen size and test temperature on the viscoelastic properties of SU-8 photoresist films are described. Films with the thicknesses of 1 μm and 10 μm are subjected to quasi-static uniaxial tensile tests and stress relaxation tests at temperatures ranging from 293 K to 473 K. The average glassy modulus at 293 K is 3.2 GPa, which decreases with an increase in the test temperature irrespective of specimen size. The mean fracture strain depends on film thickness as well as temperature. The fracture strain of the 1-μm thick films is approximately half of that of the 10-μm thick films at each temperature. Stress relaxation tests are conducted for constructing the master curves of the relaxation moduli. There is no apparent thickness dependence on the master curve. Above glass transition temperature, Tg, apparent activation energies for the two films are almost identical, whereas the activation energy for the thinner films is smaller than that for the thicker films below Tg. This size effect is discussed using Fourier transform infrared spectroscopy (FTIR).

Quasi-Static and Fatigue Fracture Strength of Microsized Silicon Film Measured by On-Chip Test Method

2000 ◽  
Author(s):  
Taeko Ando ◽  
Tetsuo Yoshioka ◽  
Mitsuhiro Shikida ◽  
Kazuo Sato
Keyword(s):  
Fracture Strain ◽  
Silicon Film ◽  
Single Crystal Silicon ◽  
Tensile Tests ◽  
Fatigue Tests ◽  
Test Method ◽  
Uniaxial Tensile ◽  
Silicon Thin Film ◽  
Crystal Silicon ◽  
On Chip

Abstract Quasi-static and fatigue tests under uniaxial tensile loading condition were carried out for single-crystal-silicon in a direction of <110> by using on-chip testing method. A film specimen and tensile testing system were integrated on a silicon chip. A measurement system allowing both quasi-static and dynamic loading was newly introduced. In quasi-static loading measured fracture strain of silicon thin-film was 3.4%. Fatigue fractures were observed during 103∼106 cycles when the maximum strains of sinusoidal wave were higher than the average fracture strain of tensile tests.

scholarly journals Mechanical Properties of Apple Skin Are Determined by Epidermis and Hypodermis

2014 ◽  
Vol 139 (2) ◽  
pp. 139-147 ◽  
Author(s):  
Bishnu P. Khanal ◽  
Moritz Knoche
Keyword(s):  
Mechanical Properties ◽  
Cold Storage ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Early Event ◽  
Unit Surface Area ◽  
Fruit Skin ◽  
Unit Surface ◽  
Cell Layers ◽  
Apple Cultivars

Mechanical failure of the fruit skin is an early event in the etiology of the disorders russeting and skin spots in a number of apple cultivars including ‘Elstar’ (Malus ×domestica Borkh.). The objective was to quantify the mechanical properties of excised epidermal segments (ES) of fruit skin and of enzymatically isolated cuticular membranes (CM) using uniaxial tensile tests. ES thickness ranged from 0.25 to 1.8 mm because thin ES samples of more uniform thickness are difficult to prepare. Sample values for stiffness (S), maximum force () and strain at () were recorded. Measured values were adjusted by regression to refer to a hypothetical standard ES of 0.5 mm thickness. Generally, S and values were positively related to ES thickness during the preharvest period from 51 to 141 days after full bloom (DAFB) and during the postharvest period from 141 to 259 DAFB in cold storage (1.7 °C, 92% relative humidity). The recorded were independent of ES thickness. The S of a standardized ES decreased slightly from 51 to 90 DAFB, then increased up to 161 DAFB, and then declined. There were essentially no differences in S recorded for isolated CM and ES. The and were highest in young fruit at 51 DAFB but decreased steadily toward harvest and continued to decrease in cold storage after harvest but at a lower rate. The and were markedly lower for CM samples than for ES ones. Monitoring the increased incidence of CM microcracking during a tensile test performed on an ES revealed that CM failure preceded ES failure. The decrease in the for ES during fruit development was accounted for in part by a decrease in the mass of cell wall per unit surface area. Our results show that the epidermal and hypodermal cell layers represent the structural backbone of an apple skin during pre- and postharvest development. Furthermore, CM microcracking has limited relevance to the overall mechanical properties of the skin.

scholarly journals Texture Selection Mechanisms during Recrystallization and Grain Growth of a Magnesium-Erbium-Zinc Alloy

Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 171
Author(s):  
Fatim-Zahra Mouhib ◽  
Fengyang Sheng ◽  
Ramandeep Mandia ◽  
Risheng Pei ◽  
Sandra Korte-Kerzel ◽  
...  
Keyword(s):  
Grain Growth ◽  
Ternary Alloy ◽  
Solute Drag ◽  
Tensile Tests ◽  
Electron Back Scatter Diffraction ◽  
Zinc Alloy ◽  
Uniaxial Tensile ◽  
Microstructural Stability ◽  
Solid Solution Strengthening ◽  
Zener Drag

Binary and ternary Mg-1%Er/Mg-1%Er-1%Zn alloys were rolled and subsequently subjected to various heat treatments to study texture selection during recrystallization and following grain growth. The results revealed favorable texture alterations in both alloys and the formation of a unique ±40° transvers direction (TD) recrystallization texture in the ternary alloy. While the binary alloy underwent a continuous alteration of its texture and grain size throughout recrystallization and grain growth, the ternary alloy showed a rapid rolling (RD) to transvers direction (TD) texture transition occurring during early stages of recrystallization. Targeted electron back scatter diffraction (EBSD) analysis of the recrystallized fraction unraveled a selective growth behavior of recrystallization nuclei with TD tilted orientations that is likely attributed to solute drag effect on the mobility of specific grain boundaries. Mg-1%Er-1%Zn additionally exhibited a stunning microstructural stability during grain growth annealing. This was attributed to a fine dispersion of dense nanosized particles in the matrix that impeded grain growth by Zener drag. The mechanical properties of both alloys were determined by uniaxial tensile tests combined with EBSD assisted slip trace analysis at 5% tensile strain to investigate non-basal slip behavior. Owing to synergic alloying effects on solid solution strengthening and slip activation, as well as precipitation hardening, the ternary Mg-1%Er-1%Zn alloy demonstrated a remarkable enhancement in the yield strength, strain hardening capability, and failure ductility, compared with the Mg-1%Er alloy.

Comprehensive study on mechanical properties of coated biaxial warp-knitted fabrics

2021 ◽  
pp. 073168442110204
Author(s):  
Bin Yang ◽  
Yingying Shang ◽  
Zeliang Yu ◽  
Minger Wu ◽  
Youji Tao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Failure Modes ◽  
Least Squares Method ◽  
Tensile Tests ◽  
Tensile Creep ◽  
Base Layer ◽  
Sustained Load ◽  
Uniaxial Tensile ◽  
Membrane Structures ◽  
Knitted Fabrics

In recent years, coated fabrics have become the major material used in membrane structures. Due to the special structure of base layer and mechanical properties, coated biaxial warp-knitted fabrics are increasingly applied in pneumatic structures. In this article, the mechanical properties of coated biaxial warp-knitted fabrics are investigated comprehensively. First, off-axial tensile tests are carried out in seven in-plane directions: 0°, 15°, 30°, 45°, 60°, 75°, and 90°. Based on the stress–strain relationship, tensile strengths are obtained and failure modes are studied. The adaptability of Tsai–Hill criterion is analyzed. Then, the uniaxial tensile creep test is performed under 24-h sustained load and the creep elongation is calculated. Besides, tearing strengths in warp and weft directions are obtained by tearing tests. Finally, the biaxial tensile tests under five different load ratios of 1:1, 2:1, 1:2, 1:0, and 0:1 are carried out, and the elastic constants and Poisson’s ratio are calculated using the least squares method based on linear orthotropic assumption. Moreover, biaxial specimens under four load ratios of 3:1, 1:3, 5:1, and 1:5 are further tensile tested to verify the adaptability of linear orthotropic model. These experimental data offer a deeper and comprehensive understanding of mechanical properties of coated biaxial warp-knitted fabrics and could be conveniently adopted in structural design.

scholarly journals A Flow Stress Model of 300M Steel for Isothermal Tension

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 252
Author(s):  
Rongchuang Chen ◽  
Shiyang Zhang ◽  
Xianlong Liu ◽  
Fei Feng
Keyword(s):  
Flow Stress ◽  
Constitutive Model ◽  
Tensile Deformation ◽  
Flow Behavior ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Model Parameters ◽  
Average Deviation ◽  
Cross Sectional ◽  
300M Steel

To investigate the effect of hot working parameters on the flow behavior of 300M steel under tension, hot uniaxial tensile tests were implemented under different temperatures (950 °C, 1000 °C, 1050 °C, 1100 °C, 1150 °C) and strain rates (0.01 s−1, 0.1 s−1, 1 s−1, 10 s−1). Compared with uniaxial compression, the tensile flow stress was 29.1% higher because dynamic recrystallization softening was less sufficient in the tensile stress state. The ultimate elongation of 300M steel increased with the decrease of temperature and the increase of strain rate. To eliminate the influence of sample necking on stress-strain relationship, both the stress and the strain were calibrated using the cross-sectional area of the neck zone. A constitutive model for tensile deformation was established based on the modified Arrhenius model, in which the model parameters (n, α, Q, ln(A)) were described as a function of strain. The average deviation was 6.81 MPa (6.23%), showing good accuracy of the constitutive model.

Experimental Investigation of Ti-6Al-4V with a Biaxial Tensile Test Setup at Elevated Temperature

2014 ◽  
Vol 622-623 ◽  
pp. 273-278 ◽  
Author(s):  
Marion Merklein ◽  
Sebastian Suttner ◽  
Adam Schaub
Keyword(s):  
Elevated Temperature ◽  
Elevated Temperatures ◽  
Tensile Tests ◽  
Advanced Materials ◽  
Uniaxial Tensile ◽  
Plastic Yielding ◽  
Characterization Methods ◽  
Specific Strength ◽  
Biaxial Tensile ◽  
Stress States

The requirement for products to reduce weight while maintaining strength is a major challenge to the development of new advanced materials. Especially in the field of human medicine or aviation and aeronautics new materials are needed to satisfy increasing demands. Therefore the titanium alloy Ti-6Al-4V with its high specific strength and an outstanding corrosion resistance is used for high and reliable performance in sheet metal forming processes as well as in medical applications. Due to a meaningful and accurate numerical process design and to improve the prediction accuracy of the numerical model, advanced material characterization methods are required. To expand the formability and to skillfully use the advantage of Ti-6Al-4V, forming processes are performed at elevated temperatures. Thus the investigation of plastic yielding at different stress states and at an elevated temperature of 400°C is presented in this paper. For this reason biaxial tensile tests with a cruciform shaped specimen are realized at 400°C in addition to uniaxial tensile tests. Moreover the beginning of plastic yielding is analyzed in the first quadrant of the stress space with regard to complex material modeling.

Effect of Polyvinyl Alcohol Concentration on the Mechanical Properties of Collagen/Polyvinyl Alcohol Blends

2015 ◽  
Vol 732 ◽  
pp. 161-164 ◽  
Author(s):  
Jan Vesely ◽  
Lukas Horny ◽  
Hynek Chlup ◽  
Milos Beran ◽  
Milan Krajicek ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Stress ◽  
Polyvinyl Alcohol ◽  
Modulus Of Elasticity ◽  
Tensile Tests ◽  
Ultimate Tensile Stress ◽  
Alcohol Concentration ◽  
Uniaxial Tensile ◽  
Initial Modulus ◽  
Water Saturated

The effects of the polyvinyl alcohol (PVA) concentration on mechanical properties of hydrogels based on blends of native or denatured collagen / PVA were examined. Blends of PVA with collagen were obtained by mixing the solutions in different ratios, using glycerol as a plasticizer. The solutions were cast on polystyrene plates and the solvent was allowed to evaporate at room temperature. Uniaxial tensile tests were performed in order to obtain the initial modulus of elasticity (up to deformation 0.1), the ultimate tensile stress and the deformation at failure of the material in the water-saturated hydrogel form. It was found that the material was elastic and the addition of PVA helped to enhance both the ultimate tensile stress and modulus of elasticity of the films. Samples prepared from denaturated collagen showed the higher ultimate tensile stress and the deformation at failure in comparison with those prepared from native collagen. The results suggest that we could expect successful application of the collagen/PVA biomaterial for tissue engineering.

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