DEM analysis of small and small-to-medium strain shear modulus of sands

The effect of dynamic curing of PP/EPDM blends with sulfur and thiuram disulfide systems on their mechanical properties was studied. The results were interpreted using the knowledge of the formation of phase structure in the blends during their melt mixing. It was shown, that a sufficiently slow curing reaction is necessary if a high impact strength is to be obtained. Only in such case, a fine and homogeneous dispersion of elastomer can be formed, which is the necessary condition for high impact strength of the blend. Using an inhibitor of curing in the system and a one-step method of dynamic curing leads to an increase in impact strength of blends. From the comparison of shear modulus and impact strength values, it follows that, at the stiffness, the dynamically cured blends have higher impact strength than the uncured ones.

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A Method for Extracting Some Key Terrain Features from Shaded Relief of Digital Terrain Models

Remote Sensing ◽

10.3390/rs12172809 ◽

2020 ◽

Vol 12 (17) ◽

pp. 2809

Author(s):

Meirman Syzdykbayev ◽

Bobak Karimi ◽

Hassan A. Karimi

Keyword(s):

Land Surface ◽

Basic Research ◽

Probabilistic Methods ◽

Detection Methods ◽

Computational Techniques ◽

Surface Evolution ◽

Dem Analysis ◽

High Degree ◽

Terrain Features ◽

Shaded Relief

Detection of terrain features (ridges, spurs, cliffs, and peaks) is a basic research topic in digital elevation model (DEM) analysis and is essential for learning about factors that influence terrain surfaces, such as geologic structures and geomorphologic processes. Detection of terrain features based on general geomorphometry is challenging and has a high degree of uncertainty, mostly due to a variety of controlling factors on surface evolution in different regions. Currently, there are different computational techniques for obtaining detailed information about terrain features using DEM analysis. One of the most common techniques is numerically identifying or classifying terrain elements where regional topologies of the land surface are constructed by using DEMs or by combining derivatives of DEM. The main drawbacks of these techniques are that they cannot differentiate between ridges, spurs, and cliffs, or result in a high degree of false positives when detecting spur lines. In this paper, we propose a new method for automatically detecting terrain features such as ridges, spurs, cliffs, and peaks, using shaded relief by controlling altitude and azimuth of illumination sources on both smooth and rough surfaces. In our proposed method, we use edge detection filters based on azimuth angle on shaded relief to identify specific terrain features. Results show that the proposed method performs similar to or in some cases better (when detecting spurs than current terrain features detection methods, such as geomorphon, curvature, and probabilistic methods.

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Measurement of Young’s Modulus and Shear Modulus of Some Structures Welded Using Flux Cored Wire by Vibration Tests

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.216.151 ◽

2014 ◽

Vol 216 ◽

pp. 151-156 ◽

Cited By ~ 1

Author(s):

Liviu Bereteu ◽

Mircea Vodǎ ◽

Gheorghe Drăgănescu

Keyword(s):

Shear Modulus ◽

Arc Welding ◽

Natural Frequencies ◽

Free Vibrations ◽

Vibration Modes ◽

Cored Wire ◽

Flux Cored Arc Welding ◽

Longitudinal Elastic Modulus ◽

Vibration Tests ◽

Non Destructive

The aim of this work was to determine by vibration tests the longitudinal elastic modulus and shear modulus of welded joints by flux cored arc welding. These two material properties are characteristic elastic constants of tensile stress respectively torsion stress and can be determined by several non-destructive methods. One of the latest non-destructive experimental techniques in this field is based on the analysis of the vibratory signal response from the welded sample. An algorithm based on Pronys series method is used for processing the acquired signal due to sample response of free vibrations. By the means of Finite Element Method (FEM), the natural frequencies and modes shapes of the same specimen of carbon steel were determined. These results help to interpret experimental measurements and the vibration modes identification, and Youngs modulus and shear modulus determination.

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Evaluation of Dynamic Properties of Sodium-Alginate-Reinforced Soil Using A Resonant-Column Test

Materials ◽

10.3390/ma14112743 ◽

2021 ◽

Vol 14 (11) ◽

pp. 2743

Author(s):

Seongnoh Ahn ◽

Jae-Eun Ryou ◽

Kwangkuk Ahn ◽

Changho Lee ◽

Jun-Dae Lee ◽

...

Keyword(s):

Shear Modulus ◽

Sodium Alginate ◽

Shear Failure ◽

Dynamic Properties ◽

Damping Ratio ◽

Reinforced Soil ◽

Resonant Column ◽

Column Test ◽

Alginate Solution ◽

Resonant Column Test

Ground reinforcement is a method used to reduce the damage caused by earthquakes. Usually, cement-based reinforcement methods are used because they are inexpensive and show excellent performance. Recently, however, reinforcement methods using eco-friendly materials have been proposed due to environmental issues. In this study, the cement reinforcement method and the biopolymer reinforcement method using sodium alginate were compared. The dynamic properties of the reinforced ground, including shear modulus and damping ratio, were measured through a resonant-column test. Also, the viscosity of sodium alginate solution, which is a non-Newtonian fluid, was also explored and found to increase with concentration. The maximum shear modulus and minimum damping ratio increased, and the linear range of the shear modulus curve decreased, when cement and sodium alginate solution were mixed. Addition of biopolymer showed similar reinforcing effect in a lesser amount of additive compared to the cement-reinforced ground, but the effect decreased above a certain viscosity because the biopolymer solution was not homogeneously distributed. This was examined through a shear-failure-mode test.

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