scholarly journals Enhanced Foamability with Shrinking Microfibers in Linear Polymer

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 211 ◽  
Author(s):  
Eric Kim ◽  
Heon Park ◽  
Carlos Lopez-Barron ◽  
Patrick Lee
Keyword(s):  
Strain Hardening ◽  
Polymer Processing ◽  
Expansion Ratio ◽  
Low Frequencies ◽  
Extensional Rheometry ◽  
Enhanced Strain ◽  
Linear Viscoelastic ◽  
Cost Efficient ◽  
Strain Hardening Behavior

Strain hardening has important roles in understanding material structures and polymer processing methods, such as foaming, film forming, and fiber extruding. A common method to improve strain hardening behavior is to chemically branch polymer structures, which is costly, thus preventing users from controlling the degree of behavior. A smart microfiber blending technology, however, would allow cost-efficient tuning of the degree of strain hardening. In this study, we investigated the effects of compounding polymers with microfibers for both shear and extensional rheological behaviors and characteristics and thus for the final foam morphologies formed by batch physical foaming with carbon dioxide. Extensional rheometry showed that compounding of in situ shrinking microfibers significantly enhanced strain hardening compared to compounding of nonshrinking microfibers. Shear rheometry with linear viscoelastic data showed a greater increase in both the loss and storage modulus in composites with shrinking microfibers than in those with nonshrinking microfibers at low frequencies. The batch physical foaming results demonstrated a greater increase in the cell population density and expansion ratio with in situ shrinking microfibers than with nonshrinking microfibers. The enhancement due to the shrinkage of compounded microfibers decreasing with temperature implies that the strain hardening can be tailored by changing processing conditions.

An Adaptive Binarization Method for Cost-efficient Document Image System in Wavelet Domain

2020 ◽  
Vol 64 (3) ◽  
pp. 30401-1-30401-14 ◽  
Author(s):  
Chih-Hsien Hsia ◽  
Ting-Yu Lin ◽  
Jen-Shiun Chiang
Keyword(s):  
Wavelet Transform ◽  
Discrete Wavelet Transform ◽  
Document Image ◽  
Background Information ◽  
Raspberry Pi ◽  
Discrete Wavelet ◽  
Image System ◽  
Low Frequencies ◽  
Cost Efficient ◽  
Binarization Method

Abstract In recent years, the preservation of handwritten historical documents and scripts archived by digitized images has been gradually emphasized. However, the selection of different thicknesses of the paper for printing or writing is likely to make the content of the back page seep into the front page. In order to solve this, a cost-efficient document image system is proposed. In this system, the authors use Adaptive Directional Lifting-Based Discrete Wavelet Transform to transform image data from spatial domain to frequency domain and perform on high and low frequencies, respectively. For low frequencies, the authors use local threshold to remove most background information. For high frequencies, they use modified Least Mean Square training algorithm to produce a unique weighted mask and perform convolution on original frequency, respectively. Afterward, Inverse Adaptive Directional Lifting-Based Discrete Wavelet Transform is performed to reconstruct the four subband images to a resulting image with original size. Finally, a global binarization method, Otsu’s method, is applied to transform a gray scale image to a binary image as the output result. The results show that the difference in operation time of this work between a personal computer (PC) and Raspberry Pi is little. Therefore, the proposed cost-efficient document image system which performed on Raspberry Pi embedded platform has the same performance and obtains the same results as those performed on a PC.

Comprehensive study of strain hardening behavior of CrCoNi medium-entropy alloy

2021 ◽  
pp. 160623
Author(s):  
Bo Guan ◽  
Yitao Wang ◽  
Jianbo Li ◽  
Yu Zhang ◽  
Hao Wang ◽  
...  
Keyword(s):  
Strain Hardening ◽  
Hardening Behavior ◽  
Strain Hardening Behavior ◽  
Comprehensive Study

Low Wave Number Radar Image Energy Influence on Determining Current

2012 ◽  
Vol 433-440 ◽  
pp. 6054-6059
Author(s):  
Gan Nan Yuan ◽  
Rui Cai Jia ◽  
Yun Tao Dai ◽  
Ying Li
Keyword(s):  
Wave Spectrum ◽  
Surface Current ◽  
Sea Surface ◽  
Radar Image ◽  
Wave Number ◽  
Sea State ◽  
Low Frequencies ◽  
In Situ Data ◽  
Main Effects

In the radar imaging mechanism different phenomena are present, as a result the radar image is not a direct representation of the sea state. In analyzing radar image spectra, it can be realized that all of these phenomena produce distortions in the wave spectrum. The main effects are more energy for very low frequencies. This work investigates the structure of the sea clutter spectrum, and analysis the low wave number energy influence on determining sea surface current. Then the radar measure current is validated by experiments. By comparing with the in situ data, we know that the radar results reversed by image spectrum without low wave number spectrum have high precision. The low wave number energy influent determining current seriously.

Cyclic Plasticity for Nonproportional Paths: Part 1—Cyclic Hardening, Erasure of Memory, and Subsequent Strain Hardening Experiments

1978 ◽  
Vol 100 (1) ◽  
pp. 96-103 ◽  
Author(s):  
H. S. Lamba ◽  
O. M. Sidebottom
Keyword(s):  
Strain Hardening ◽  
Effective Strain ◽  
Strain Range ◽  
Cyclic Hardening ◽  
Cyclic Plasticity ◽  
Phase Cycling ◽  
Strain Behavior ◽  
Subsequent Yield Surface ◽  
Strain Hardening Behavior ◽  
Annealed Copper

Extensive experiments were conducted on annealed copper under cyclic nonproportional strain histories. After cyclically stabilizing the material by uniaxial cycling, out-of-phase axial-shear strain cycling for the same effective strain range caused additional increases in stress amplitudes to restabilized levels. Following cyclic stabilization of the material under out-of-phase cycling, a cycle whose effective strain amplitude was comparable to those of previous cycles resulted in stress-strain behavior unique to that cycle and independent of prior stable deformation. The experimental verification of this material property, which has been the subject of much conjecture, allowed the design of a fundamental class of experiments that determined the subsequent yield surface and strain hardening behavior from only one specimen.

The role of forest deadwood in rockfall protection

2021 ◽  
Author(s):  
Adrian Ringenbach ◽  
Peter Bebi ◽  
Perry Bartelt ◽  
Andrin Caviezel
Keyword(s):  
Basal Area ◽  
Spruce Forest ◽  
Runout Distance ◽  
In Situ Sensors ◽  
Efficient Protection ◽  
Cost Efficient ◽  
Study Sites ◽  
Rockfall Protection

<p>Forests with a high density and basal area of living trees are known for their function as natural and cost-efficient protection against rockfall. The role of deadwood, however, is less understood. We address this knowledge gap in this contribution as we present the results of repeated real-scale experiments in a) a montane beech-spruce forest with and without deadwood and b) in a subalpine scrub mountain pine-spruce forest with deadwood. We used artificial rocks with either an equant or platy shape, masses between 45 kg and 800 kg (≈ 0.3 m3), and equipped with in-situ sensors to gain insights into rotational velocities and impact-accelerations. Clusters of deadwood and erected root plates reduced the mean runout distance at both study sites. For site a), we found that more rocks were stopped behind lying than living trees and that the stopping effect of deadwood was greater for equant compared to platy rock shapes. Site b) revealed a braking effect of scrub mountain pines for relatively small (45 kg), but also a visible reduction in rotational velocities for the 800 kg rocks sensor stream. We conclude that deadwood must be taken into account in rockfall modeling and the management of rockfall protection forests.</p>

Revealing the strain-hardening behavior of twinning-induced plasticity steels: Theory, simulations, experiments

2013 ◽  
Vol 61 (2) ◽  
pp. 494-510 ◽  
Author(s):  
David R. Steinmetz ◽  
Tom Jäpel ◽  
Burkhard Wietbrock ◽  
Philip Eisenlohr ◽  
Ivan Gutierrez-Urrutia ◽  
...  
Keyword(s):  
Strain Hardening ◽  
Hardening Behavior ◽  
Strain Hardening Behavior
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