A Simple Method for Determining the Coefficient of Restitution

In this paper, a simple method for measuring the recovery coefficient of gravel was proposed by the definition of the coefficient of restitution and the principle of kinematics. The recovery coefficient between gravel and slate was obtained by the experiment; meanwhile the reason of error was analyzed and discussed. Finally, the experimental results were compared with the simulation data of the EDEM software. It was concluded that the data were more appropriate when the gravel particles were smaller.

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Models for Materials Damping, Loss Factor, and Coefficient of Restitution

Journal of Engineering Materials and Technology ◽

10.1115/1.4044281 ◽

2019 ◽

Vol 142 (1) ◽

Cited By ~ 1

Author(s):

Hany A. Sherif ◽

Fahad. A. Almufadi

Keyword(s):

Loss Factor ◽

Polymeric Materials ◽

Theoretical Models ◽

Coefficient Of Restitution ◽

Complex Model ◽

Damping Coefficient ◽

Damping Factor ◽

Simple Method ◽

Adopted Model ◽

The Impact

Common parameters between metallic and polymeric materials are the coefficient of restitution, the damping coefficient, and loss factor. Although the relationship between the coefficient of restitution and the loss factor is quite direct, their dependence on the damping coefficient is not so simple and mainly affected by the adopted model used to describe the material response under impact. In the present study, Kelvin–Voigt linear model and Hunt–Crossley complex model are analyzed to describe how the coefficient of restitution depends on the viscous damping coefficient of impact. The correlation between the theoretical models and the experimental data is also shown. A simple method to predict the impact damping factor of both polymeric and metallic materials from the measured temporal signal of the impact force is demonstrated.

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A simple way for producing holographic filters suitable for image improvement

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100108271 ◽

1978 ◽

Vol 36 (1) ◽

pp. 226-227

Author(s):

K.-H. Herrmann ◽

E. Reuber ◽

P. Schiske

Keyword(s):

Transfer Functions ◽

Diffraction Order ◽

Lateral Position ◽

Simple Method ◽

Spatial Frequencies ◽

Resolution Electron ◽

Wiener Filters ◽

Image Improvement ◽

Optical Reconstruction ◽

Set Up

Aposteriori deblurring of high resolution electron micrographs of weak phase objects can be performed by holographic filters [1,2] which are arranged in the Fourier domain of a light-optical reconstruction set-up. According to the diffraction efficiency and the lateral position of the grating structure, the filters permit adjustment of the amplitudes and phases of the spatial frequencies in the image which is obtained in the first diffraction order.In the case of bright field imaging with axial illumination, the Contrast Transfer Functions (CTF) are oscillating, but real. For different imageforming conditions and several signal-to-noise ratios an extensive set of Wiener-filters should be available. A simple method of producing such filters by only photographic and mechanical means will be described here.A transparent master grating with 6.25 lines/mm and 160 mm diameter was produced by a high precision computer plotter. It is photographed through a rotating mask, plotted by a standard plotter.

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Rotary Beveling for In Situ Thin-Section Microscopy of Cell Cultures

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100099192 ◽

1981 ◽

Vol 39 ◽

pp. 550-551

Author(s):

Dean A. Handley ◽

Jack T. Alexander ◽

Shu Chien

Keyword(s):

Cell Growth ◽

Cell Cultures ◽

Molecular Interactions ◽

Convenient Method ◽

Petri Dish ◽

Simple Method ◽

Thin Section Microscopy ◽

Thin Sectioning ◽

Organic Fluids

In situ preparation of cell cultures for ultrastructural investigations is a convenient method by which fixation, dehydration and embedment are carried out in the culture petri dish. The in situ method offers the advantage of preserving the native orientation of cell-cell interactions, junctional regions and overlapping configurations. In order to section after embedment, the petri dish is usually separated from the polymerized resin by either differential cryo-contraction or solvation in organic fluids. The remaining resin block must be re-embedded before sectioning. Although removal of the petri dish may not disrupt the native cellular geometry, it does sacrifice what is now recognized as an important characteristic of cell growth: cell-substratum molecular interactions. To preserve the topographic cell-substratum relationship, we developed a simple method of tapered rotary beveling to reduce the petri dish thickness to a dimension suitable for direct thin sectioning.

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