Internal Stress Generation in Rattan Canes

IAWA Journal ◽  
1999 ◽  
Vol 20 (1) ◽  
pp. 45-58 ◽  
Author(s):  
Willie Abasolo ◽  
Masato Yoshida ◽  
Hiroyuki Yamamoto ◽  
Takashi Okuyama
Keyword(s):  
Tensile Stress ◽  
Internal Stress ◽  
Compressive Stress ◽  
Compression Wood ◽  
Lignin Content ◽  
Stress Generation ◽  
Tensile Stresses ◽  
Stress Development ◽  
The Core ◽  
Compressive Stresses

Internal stress development was investigated in rattan canes (Calamus merrillii Becc.) following the procedures used in trees. Measurements showed that longitudinal compressive stresses existed at the periphery while longitudinal tensile stresses existed at the core. Such stresses originated from the fibers. Fiber MFA was observed to be beyond 20" and the lignin content was above 30%. Considering its similarities to compression wood tracheids, it was assumed that the rattan fibers generated longitudinal compressive stress. The amount of stress varied from base to top and from periphery to core because of the variation in the proportion of fibers along these points. This is why the longitudinal compressive stress that was generated at the base was higher than at the top and high longitudinal compressive stress was developed at the periphery. As a response to this high peripheral stress, longitudinal tensile stress was induced at the core.

scholarly journals Long-Term Behaviour of Precast Concrete Deck Using Longitudinal Prestressed Tendons in Composite I-Girder Bridges

2018 ◽  
Vol 8 (12) ◽  
pp. 2598 ◽  
Author(s):  
Haiying Ma ◽  
Xuefei Shi ◽  
Yin Zhang
Keyword(s):  
Tensile Stress ◽  
Compressive Stress ◽  
Precast Concrete ◽  
Concrete Strength ◽  
Steel Girders ◽  
Concrete Creep ◽  
Compressive Stresses ◽  
Girder Bridge ◽  
Concrete Deck

Twin-I girder bridge systems composite with precast concrete deck have advantages including construction simplification and improved concrete strength compared with traditional multi-I girder bridge systems with cast-in-place concrete deck. But the cracking is still a big issue at interior support for continuous span bridges using twin-I girders. To reduce cracks occurrence in the hogging regions subject to negative moments and to guarantee the durability of bridges, the most essential way is to reduce the tensile stress of concrete deck within the hogging regions. In this paper, the prestressed tendons are arranged to prestress the precast concrete deck before it is connected with the steel girders. In this way, the initial compressive stress induced by the prestressed tendons in the concrete deck within the hogging region is much higher than that in regular concrete deck without prestressed tendons. A finite element analysis is developed to study the long-term behaviour of prestressed concrete deck for a twin-I girder bridge. The results show that the prestressed tendons induce large compressive stresses in the concrete deck but the compressive stresses are reduced due to concrete creep. The final compressive stresses in the concrete deck are about half of the initial compressive stresses. Additionally, parametric study is conducted to find the effect to the long-term behaviour of concrete deck including girder depth, deck size, prestressing stress and additional imposed load. The results show that the prestressing compressive stress in precast concrete deck is transferred to steel girders due to concrete creep. The prestressed forces transfer between the concrete deck and steel girder cause the loss of compressive stresses in precast concrete deck. The prestressed tendons can introduce some compressive stress in the concrete deck to overcome the tensile stress induced by the live load but the force transfer due to concrete creep needs be considered. The concrete creep makes the compressive stress loss and the force redistribution in the hogging regions, which should be considered in the design the twin-I girder bridge composite with prestressed precast concrete deck.

scholarly journals Local, transient tensile stress on the nuclear membrane causes membrane rupture

2019 ◽  
Vol 30 (7) ◽  
pp. 899-906 ◽  
Author(s):  
Qiao Zhang ◽  
Andrew C. Tamashunas ◽  
Ashutosh Agrawal ◽  
Mehdi Torbati ◽  
Aditya Katiyar ◽  
...  
Keyword(s):  
Tensile Stress ◽  
Nuclear Membrane ◽  
Mammary Epithelial Cells ◽  
Mammary Epithelial ◽  
Tensile Stresses ◽  
Membrane Rupture ◽  
Nuclear Membranes ◽  
Compressive Stresses ◽  
Diffusive Fluxes ◽  
Nuclear Deformations

Cancer cell migration through narrow constrictions generates compressive stresses on the nucleus that deform it and cause rupture of nuclear membranes. Nuclear membrane rupture allows uncontrolled exchange between nuclear and cytoplasmic contents. Local tensile stresses can also cause nuclear deformations, but whether such deformations are accompanied by nuclear membrane rupture is unknown. Here we used a direct force probe to locally deform the nucleus by applying a transient tensile stress to the nuclear membrane. We found that a transient (∼0.2 s) deformation (∼1% projected area strain) in normal mammary epithelial cells (MCF-10A cells) was sufficient to cause rupture of the nuclear membrane. Nuclear membrane rupture scaled with the magnitude of nuclear deformation and the magnitude of applied tensile stress. Comparison of diffusive fluxes of nuclear probes between wild-type and lamin-depleted MCF-10A cells revealed that lamin A/C, but not lamin B2, protects the nuclear membranes against rupture from tensile stress. Our results suggest that transient nuclear deformations typically caused by local tensile stresses are sufficient to cause nuclear membrane rupture.

scholarly journals Direct observation of pore collapse and tensile stress generation on pore walls due to salt crystallization in a PDMS channel

Soft Matter ◽  
2019 ◽  
Vol 15 (22) ◽  
pp. 4562-4569 ◽  
Author(s):  
Antoine Naillon ◽  
Pierre Joseph ◽  
Marc Prat
Keyword(s):  
Tensile Stress ◽  
Compressive Stress ◽  
Direct Observation ◽  
Stress Generation ◽  
Salt Crystallization ◽  
Pore Collapse ◽  
Crystallization Pressure ◽  
Salt Crystallisation ◽  
Pdms Channel ◽  
Classical Picture

In contrast with the classical picture where the generation of stress on pore walls due to salt crystallisation is analysed by a compressive stress using the concept of crystallization pressure, we report a mechanism leading to the generation of a local tensile stress.

INTERNAL STRESS OF CHROME COATINGS ELECTRODEPOSITED FROM SOLUTIONS OF CHROMIUM (III) SALTS

2019 ◽  
Vol 62 (12) ◽  
pp. 33-38 ◽  
Author(s):  
Evgeniy G. Vinokurov
Keyword(s):  
Experimental Data ◽  
Tensile Stress ◽  
Internal Stress ◽  
Compressive Stress ◽  
Current Density ◽  
Plate Thickness ◽  
Similar Data ◽  
Thin Coatings ◽  
The Difference

Experimental data on internal stress in chromium coatings electrodeposited from Cr(III)-solutions have been obtained. Tensile stress 250-300 MPa is observed in thin coatings with thickness was below 1-3 μm. The internal stress is practically independent on current density and pH of the solution. A reduction in the plate thickness corresponding to σ=0 is observed, when pH has changed from 1.2 to 1.6 and current density from 30 to 35 A/dm2 at higher values of pH and current density compressive stress is observed and increases the difference in the stress values at greater thicknesses of the coatings: ((– 10) - (– 50) MPa). These results have been compared with similar data for the coatings deposited from Cr(VI) solutions including the effects of the non-metal inclusions in the coatings (for Cr(III)-bath H – 10.5 - 13 at. % (26 - 32 ml H2 / g Cr), O – 0.06-0.6 at. %, С – 0.04-7.8 at. %; for Cr(VI)-bath H – 1.8 at. %, O – 1.2 at. %, С – 0 at. %)). Compressive stress, related with the inclusions (including carbides) is the major cause, limiting the possibility to improve the characteristics of chromium coatings and to deposit coatings of the quality comparable to that of chrome plated from Cr(VI) baths.

Effect of internal stress on elemental diffusion and crystallization of electroless Ni–Cu–P deposit on Al

2003 ◽  
Vol 18 (9) ◽  
pp. 2221-2227 ◽  
Author(s):  
Jen-Che Hsu ◽  
Kwang-Lung Lin
Keyword(s):  
Tensile Stress ◽  
Diffusion Couple ◽  
Internal Stress ◽  
Compressive Stress ◽  
Crystallization Behavior ◽  
Amorphous Structure ◽  
Diffusion Behavior ◽  
Elemental Diffusion ◽  
Plating Solution ◽  
Electroless Ni

The type and magnitude of stress in electroless Ni–Cu–P deposits on Al were manipulated by controlling the concentration of saccharin in the plating solution. Tensile, zero, and compressive stress of the electroless Ni–Cu–P deposits was obtained with 0, 8, and 10 g/l saccharin for studying the effect of stress on the diffusion and crystallization behavior of the deposit. The effect of stress on the diffusion behavior of Cu, Ni, and Al elements during annealing was investigated. Interdiffusion between Al and Ni in an amorphous Ni–Cu–P/crystal Al diffusion couple is abated by the effects of amorphous structure, atomic affinity, and backstress. Therefore, the effect of stress on diffusion is manifested by Cu elemental diffusion. The tensile stress promotes the formation of Ni3P and the diffusion of Cu into the substrate.

Tensile and Compressive Responses of Nociceptors in Rat Hairy Skin

1997 ◽  
Vol 78 (1) ◽  
pp. 492-505 ◽  
Author(s):  
Partap S. Khalsa ◽  
Robert H. Lamotte ◽  
Peter Grigg
Keyword(s):  
Compressive Stress ◽  
Compressive Loading ◽  
Skin Thickness ◽  
Tensile Stresses ◽  
Compressive Stresses ◽  
Hairy Skin ◽  
Surface Displacements ◽  
Compressive Loads ◽  
Tension And Compression ◽  
Highly Uniform

Khalsa, Partap S., Robert H. LaMotte, and Peter Grigg. Tensive and compressive responses of nociceptors in rat hairy skin. J. Neurophysiol. 78: 492–505, 1997. Mechanically sensitive nociceptor afferents were studied in a preparation of isolated skin from rat leg. Each neuron was studied while the skin was subjected to tensile and compressive loading. The experiment was designed to create highly uniform states of stress in both tension and compression. Tensile loads were applied by pulling on the edges of the sample. Applied loads were used to determine the tensile stresses. Surface displacements were used to determine tensile strains. Compressive loads were applied by indenting the surface of the skin with flat indenter tips applied under force control. The skin was supported by a flat, hard substrate. Compressive stresses were determined from the applied loads and tip geometry. Compressive strains were determined from skin thickness and tip excursions. All nociceptors were activated by both tensile and compressive loading. There was no interaction between the responses to compressive and tensile stimuli (i.e., the responses were simply additive). Responses of nociceptors were better related to tensile and compressive stresses than to strains. Nociceptors responded better to tensile loading than to compressive loading. Response thresholds were lower and sensitivities were higher for tensile stress than for compressive stress. The response to compression was better related to compressive stress than to other stimulus parameters (i.e., load/circumference or simply load). Indentations of intact skin over a soft substrate such as muscle would be expected to cause widespread activation of nociceptors because of tensile stresses.

"New Donors" in Czochralski Grown Silicon Annealed at T≥ 600°C under Compressive Stress

2005 ◽  
Vol 108-109 ◽  
pp. 181-186 ◽  
Author(s):  
Valentin V. Emtsev ◽  
Boris A. Andreev ◽  
Gagik A. Oganesyan ◽  
D.I. Kryzhkov ◽  
Andrzej Misiuk ◽  
...  
Keyword(s):  
Mechanical Stress ◽  
Compressive Stress ◽  
Reference Temperature ◽  
Enhancement Effect ◽  
Shallow Acceptor ◽  
Thermal Donor ◽  
Compressive Stresses ◽  
Heat Treated ◽  
Donor Formation ◽  
New Donors

Effects of compressive stress on oxygen agglomeration processes in Czochralski grown silicon heat treated at T= 450OC, used as a reference temperature, and T= 600OC to 800OC are investigated in some detail. Compressive stresses of about P= 1 GPa lead to enhanced formation of Thermal Double Donors in materials annealed over a temperature range of T= 450OC – 600OC. It has been shown that the formation of thermal donors at T= 450OC under normal conditions and compressive stress is accompanied with loss of substitutional boron. In contrast, the concentration of the shallow acceptor states of substitutional boron in silicon annealed under stress at T≥ 600OC remains constant. An enhancement effect of thermal donor formation is gradually weakened at T≥ 700OC. The oxygen diffusivity sensitive to mechanical stress is believed to be responsible for the observed effects in heat-treated silicon.

scholarly journals Stress–strain relationship model of glulam bamboo under axial loading

2020 ◽  
Vol 29 ◽  
pp. 2633366X2095872
Author(s):  
Yang Wei ◽  
Mengqian Zhou ◽  
Kunpeng Zhao ◽  
Kang Zhao ◽  
Guofen Li
Keyword(s):  
Tensile Stress ◽  
Compressive Stress ◽  
Failure Modes ◽  
Axial Loading ◽  
Tensile Failure ◽  
Stress Strain ◽  
Laminated Bamboo ◽  
Bamboo Scrimber ◽  
Strain Relationship ◽  
Strain Model

Glulam bamboo has been preliminarily explored for use as a structural building material, and its stress–strain model under axial loading has a fundamental role in the analysis of bamboo components. To study the tension and compression behaviour of glulam bamboo, the bamboo scrimber and laminated bamboo as two kinds of typical glulam bamboo materials were tested under axial loading. Their mechanical behaviour and failure modes were investigated. The results showed that the bamboo scrimber and laminated bamboo have similar failure modes. For tensile failure, bamboo fibres were ruptured with sawtooth failure surfaces shown as brittle failure; for compression failure, the two modes of compression are buckling and compression shear failure. The stress–strain relationship curves of the bamboo scrimber and laminated bamboo are also similar. The tensile stress–strain curves showed a linear relationship, and the compressive stress–strain curves can be divided into three stages: elastic, elastoplastic and post-yield. Based on the test results, the stress–strain model was proposed for glulam bamboo, in which a linear equation was used to describe the tensile stress–strain relationship and the Richard–Abbott model was employed to model the compressive stress–strain relationship. A comparison with the experimental results shows that the predicted results are in good agreement with the experimental curves.

The Influence of Different Subbase Materials on the Crack of Cement Stabilized Macadam Base during Construction

2012 ◽  
Vol 591-593 ◽  
pp. 955-959 ◽  
Author(s):  
Xiao Feng Liao ◽  
Fen Xiao ◽  
Zhong Da Chen ◽  
Lei Xing
Keyword(s):  
Tensile Stress ◽  
Shrinkage Strain ◽  
Mechanical Parameters ◽  
Tensile Stresses ◽  
Shrinkage Crack ◽  
Dry Shrinkage ◽  
Base Course ◽  
Shrinkage Coefficient ◽  
Crack Space

According to actual axle load data and the measured mechanical parameters of cement stabilized macadam material with different cement dosages, the bottom tensile stresses of different subbase structures are calculated and the results show that: to graded gravel subbase, the weight of construction vehicle is inadvisable to be more than 35t and the cement dosage of base course shall be more than 3.0%; and, the maximum bottom tensile stress of graded gravel subbase shall be much more than that of lime-flyash soil subbase. According to the measured dry shrinkage strain and dry shrinkage coefficient, the dry shrinkage crack space of base course is analyzed and the results show that: under the same cement dosage, the crack space of the base course with graded gravel subbase is smaller than that of lime-flyash soil subbase; with the increase of cement dosage, the crack space of base course increase first and then decrease, and when the cement dosage is 3.5%, the dry shrinkage strain and dry shrinkage coefficient is minimum and the crack space of base course is maximum.

Experimental Study on the Relationship between Dislocation Density and Internal Stress in Micro Electroforming Layer

2015 ◽  
Vol 645-646 ◽  
pp. 405-410 ◽  
Author(s):  
Chang Song ◽  
Li Qun Du ◽  
Tong Yang ◽  
Lei Luo ◽  
You Sheng Tao ◽  
...  
Keyword(s):  
Experimental Study ◽  
Dislocation Density ◽  
Internal Stress ◽  
Compressive Stress ◽  
Stress Relief ◽  
Ultrasonic Power ◽  
Pile Up ◽  
Ultrasonic Stress Relief ◽  
The Relationship ◽  
Dislocation Density Increase

In the micro electroforming process, the existence of electroforming layer defects caused by macro internal stress seriously limits the application and development of the micro electroforming technology. Currently, some studies have shown that ultrasonic can reduce the internal stress. But the formation process of the internal stress and the mechanism of ultrasonic stress relief in micro electroforming layer are still unclear now. In this paper, the relationship between dislocation density and internal stress under ultrasonic was studied. The results show that the ultrasonic can make the dislocation density increase and the compressive stress decrease. When the ultrasonic power is 200W, the dislocation density and the compressive stress culminate 3.8×10-15m-2 and-144.4MPa, respectively. The ultrasonic can excite the movement of dislocation proliferation, pile-up and opening, which leads to a micro plastic deformation in the crystal, and thereby releases the internal stress.

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