scholarly journals Room Temperature Ferroelastic Creep Behavior of Porous (La0.6Sr0.4)0.95Co0.2Fe0.8O3-δ

Processes ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 1346
Author(s):  
Barbara Arnauda ◽  
Ali Akbari-Fakhrabadi ◽  
Nina Orlovskaya ◽  
Viviana Meruane ◽  
Wakako Araki
Keyword(s):  
Room Temperature ◽  
Time Dependent ◽  
Compression Stress ◽  
Lateral Stress ◽  
Deformation Curves ◽  
Lateral Contraction ◽  
Negative Creep ◽  
Creep Deformations ◽  
Uniaxial Compressive Stress ◽  
Applied Stresses

The time-dependent deformation of porous (La0.6Sr0.4)0.95Co0.2Fe0.8O3-δ (LSCF) under constant uniaxial compressive stress at room temperature has been studied. Both axial and lateral stress–strain deformation curves clearly show the non-linear ferroelastic behavior of LSCF perovskite during compression. The ferroelastic characteristics of deformation curves such as coercive stress and apparent loading moduli decrease when the porosity of the samples increases. Ferroelastic creep deformations at applied stresses of 25 and 50 MPa demonstrate that stress and porosity are influencing factors on creep deformation, which increases with increasing stress and porosity. A negative creep or axial expansion and lateral contraction were observed in the sample with 35% porosity under 50-MPa constant compression stress.

scholarly journals Revealing the Plastic Mode of Time-Dependent Deformation of a LiTaO3 Single Crystal by Nanoindentation

Micromachines ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 878
Author(s):  
Shengyun Zhou ◽  
Xianwei Huang ◽  
Congda Lu ◽  
Yunfeng Liu ◽  
Taihua Zhang ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Single Crystal ◽  
Room Temperature ◽  
Time Dependent ◽  
High Shear ◽  
Compression Stress ◽  
Creep Flow ◽  
Secondary Cracks ◽  
Loading Sequence ◽  
Surface Morphologies

Recently, instrumental nanoindentation has been widely applied to detect time-dependent plastic deformation or creep behavior in numerous materials, particularly thin films and heterogeneous materials. However, deformation mechanism at nanoindentation holding stage has not been well revealed hitherto. In the current work, nanoindentation holding tests with high loads were performed on a brittle LiTaO3 single crystal. The surface morphologies of residual impressions with various holding times were investigated. It was indicated that generation of secondary cracks and propagation of both main and secondary cracks were the dominating mechanism for time-dependent plastic deformation at the initial holding stage, and the density and length of cracks were invariable at the steady-state holding stage, which suggested a nonlocalized plastic deformation beneath the indenter. It could be concluded that time-dependent plastic deformation of brittle ceramic under nanoindentation is composed of instant cracking as the continuation of loading sequence and homogeneous creep flow by high shear-compression stress at room temperature.

scholarly journals A Facile Co-crystallization Approach to Fabricate Two-component Carbon Dots Composites Showing Time-Dependent Evolutive Room Temperature Phosphorescence Colors

2021 ◽  
Author(s):  
Jian Qu ◽  
Xin Zhang ◽  
Zhong-Jie Wang ◽  
Shuyan Zhang ◽  
Yejian Yu ◽  
...  
Keyword(s):  
Carbon Dots ◽  
Room Temperature ◽  
Data Encryption ◽  
Time Dependent ◽  
Security Level ◽  
Room Temperature Phosphorescence ◽  
Two Component ◽  
Carbon Based

Time-dependent evolutive afterglow materials can increase the security level by providing additional encryption modes in anti-counterfeiting and data encryption. The design of carbon-based materials with dynamic afterglow colors is attractive...

scholarly journals Artifacts associated with mithramycin fluorescence in the clinical detection and quantitation of aneuploidy by flow cytometry.

1982 ◽  
Vol 30 (4) ◽  
pp. 317-322 ◽  
Author(s):  
R E Cunningham ◽  
K S Skramstad ◽  
A E Newburger ◽  
S E Shackney
Keyword(s):  
Flow Cytometry ◽  
Room Temperature ◽  
Human Melanoma ◽  
Time Dependent ◽  
Clinical Samples ◽  
Fixation Time ◽  
C Cells ◽  
Temperature Dependent ◽  
Clinical Detection

Ethanol-fixed cells stored at 4 degrees C exhibit fixation time-dependent hyperchromatism in comparison with freshly fixed cells when stained with mithramycin and examined by flow cytometry. This hyperchromatism has been found to be temperature-dependent, developing fully within 72 hr at room temperature, and within 2 hr at 37 degrees C. Cells from normal donors that are stained with mithramycin exhibit spurious aneuploid peaks. These spurious aneuploid peaks can be eliminated by incubating ethanol-fixed cells at 37 degrees C for 2 hr prior to staining; true aneuploidy is not affected by this procedure. In rare instances, cytoplasmic fluorescence can be observed in mithramycin-stained cells. In addition, unexplained hypochromatism and hyperchromatism can be observed in some clinical samples, particularly in human melanoma. The effects of these unexplained staining artifacts can be minimized or eliminated by adopting strict criteria for the clinical detection of aneuploidy by flow cytometry.

The use of a bree simulation to investigate strain accumulation in 316 stainless steel at temperatures between room temperature and 500°c

1989 ◽  
Vol 24 (2) ◽  
pp. 95-102 ◽  
Author(s):  
D J Brookfield ◽  
D N Moreton
Keyword(s):  
Stainless Steel ◽  
Transition Temperature ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Cyclic Change ◽  
Strain Accumulation ◽  
Temperature Behaviour ◽  
Design Rules ◽  
Axial Tension ◽  
Applied Stresses

This paper details tests undertaken to determine the 1 per cent strain accumulation boundary in stainless steel type 316 strip subjected to constant axial tension and a cyclic change of curvature. Boundaries are obtained for temperatures between 300 and 500°C. These are compared with two design rules, both of which are shown to be conservative. Additionally, the temperature at which the transition from the characteristic room temperature behaviour of continued ratchetting to the ‘shakedown’ observed at elevated temperatures is investigated. Results obtained indicate that this transition temperature is influenced by the magnitude of the applied stresses.

scholarly journals Chiral Separation of rac-Propylene Oxide on Penicillamine Coated Gold NPs

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1716
Author(s):  
Nisha Shukla ◽  
Zachary Blonder ◽  
Andrew J. Gellman
Keyword(s):  
Propylene Oxide ◽  
Room Temperature ◽  
Adsorption Properties ◽  
Time Dependent ◽  
Prior Work ◽  
Au Nps ◽  
The Past ◽  
Racemic Mixtures ◽  
Enantioselective Adsorption ◽  
Gold Nps

The surfaces of chemically synthesized spherical gold NPs (Au-NPs) have been modified using chiral L- or D-penicillamine (Pen) in order to impart enantioselective adsorption properties. These chiral Au-NPs have been used to demonstrate enantioselective adsorption of racemic propylene oxide (PO) from aqueous solution. In the past we have studied enantioselective adsorption of racemic PO on L- or D-cysteine (Cys)-coated Au-NPs. This prior work suggested that adsorption of PO on Cys-coated Au-NPs equilibrates within an hour. In this work, we have studied the effect of time on the enantioselective adsorption of racemic PO from solution onto chiral Pen/Au-NPs. Enantioselective adsorption of PO on chiral Pen/Au-NPs is time-dependent but reaches a steady state after ~18 h at room temperature. More importantly, L- or D-Pen/Au-NPs are shown to adsorb R- or S-PO enantiospecifically and to separate the two PO enantiomers from racemic mixtures of RS-PO.

Time-dependent lateral transmission of force in skeletal muscle

2009 ◽  
Vol 465 (2108) ◽  
pp. 2441-2460 ◽  
Author(s):  
Yingxin Gao ◽  
Alan S. Wineman ◽  
Anthony M. Waas
Keyword(s):  
Skeletal Muscle ◽  
Relaxation Time ◽  
Muscle Fibre ◽  
Composite System ◽  
Stress Transfer ◽  
Time Dependent ◽  
Muscle Fibres ◽  
Strain History ◽  
Shear Stresses ◽  
Lateral Stress

There is experimental evidence to suggest that extensible connective tissues are mechanically time-dependent. In view of this, the mechanics of time-dependent lateral stress transfer in skeletal muscle is investigated by employing a viscoelastic shear lag model for the transfer of tensile stress between muscle fibres and the surrounding extracellular matrix (ECM) by means of shear stresses at the interface between the muscle fibre and the ECM. The model allows for both mechanical strains in the muscle as well as the strain owing to muscle contraction. Both the ECM and the muscle fibre are modelled as viscoelastic solids. As a result, time-dependent lateral stress transfer can be studied under a variety of loading and muscle stimulation conditions. The results show that the larger the muscle fibre creep time relative to the ECM relaxation time, the longer it takes for the muscle fibre stress to relax. It also shows that the response of the muscle–ECM composite system also depends on the characteristic time of a strain history relative to the characteristic relaxation time of the ECM. The results from the present model provide significant insight into the role of the parameters that characterize the response of the muscle composite system.

Elastic-Viscoplastic Behaviour of Plain-Woven GFRP Laminates: Analysis Using Homogenization Theory

2007 ◽  
Vol 334-335 ◽  
pp. 45-48
Author(s):  
Tetsuya Matsuda ◽  
Y. Nimiya ◽  
Nobutada Ohno ◽  
Masamichi Kawai
Keyword(s):  
Present Method ◽  
Room Temperature ◽  
Constant Strain Rate ◽  
Tensile Tests ◽  
Time Dependent ◽  
Homogenization Theory ◽  
Point Symmetry ◽  
Quantitative Prediction ◽  
Viscoplastic Deformation ◽  
Internal Structures

In the present study, a method for reducing the domain of analysis is developed for the homogenization analysis of plain-woven laminates. Moreover, the method is applied to the quantitative prediction of elastic-viscoplastic deformation of plain-woven GFRP laminates. It is first shown that the internal structures of plain-woven laminates satisfy point-symmetry on the assumption that the laminates have the in-phase or out-of-phase laminate configuration of plain fabrics. The point-symmetry is then utilized for the boundary condition of unit cell problems, reducing the domain of analysis to 1/4 and 1/8 for the in-phase and out-of-phase laminate configurations, respectively. Using the present method combined with the nonlinear time-dependent homogenization theory, the elastic-viscoplastic behavior of plain-woven GFRP laminates under in-plane on- and off-axis loading is analyzed. In addition, the tensile tests of a plain-woven GFRP laminate at a constant strain rate are performed at a room temperature. Comparing the results of the present analysis with the experimental ones, it is shown that the analysis successfully predicts the in-plane elastic-viscoplastic behavior of the plain-woven GFRP laminate.

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