Fullerene stability under shock-wave and static loading

1994 ◽  
Vol 30 (2) ◽  
pp. 259-260
Author(s):  
O. G. Epanchintsev ◽  
A. A. Dityat'ev
Keyword(s):  
Shock Wave ◽  
Static Loading ◽  
Fullerene Stability

scholarly journals Behaviour of the peach under underwater shock wave loading

2008 ◽  
Vol 56 (4) ◽  
pp. 151-160
Author(s):  
Libor Severa
Keyword(s):  
Numerical Simulation ◽  
Shock Wave ◽  
Strain Rate ◽  
Compression Test ◽  
Static Loading ◽  
Surface Velocity ◽  
Shock Wave Loading ◽  
Wave Loading ◽  
Underwater Shock Wave ◽  
Underwater Shock

The paper concerns with the experimental and numerical study of the peach (Red Haven) at underwater shock wave loading. The behaviour of the peach skin as well as peach stone can be described in terms of elasticity. Following experiments have been performed: tensile testing of the skin (exocarp) specimens at constant elongation at strain rate 0.01 s−1, compression test of the mesocarp specimens at different strain rates corresponding to quasi – static loading, compression test of the mesocarp spe­ci­mens at the high rates of strain (about 1000 s−1), and compression test of the whole peach stone at strain rate corresponding to quasi – static loading. The model of the peach has been suggested. The model is used for the numerical simulation, which was performed on the software LS DYNA 3D finite element code. Pressure wave propagation in the water has been studied and following quantities evaluated: pressure on the peach surface, displacement, and surface velocity. Two different models (Maxwell and Kelvin) have been used. The results of this simulation show some agreement with results of the observation (undamaged peach skin). The numerical simulation also gives an insight on the details of the loading, which was recently tested as a tool of fruit treatment. It has been shown that undewater shock wave treatment of peaches can lead to their softening.

scholarly journals Optimization and Experimental Investigation of the Ability of New Material from Aluminum Casting on Pumice Particles to Reduce Shock Wave

2020 ◽  
Vol 64 (3) ◽  
pp. 224-232
Author(s):  
Masoud Rahmani ◽  
Amin Moslemi Petrudi
Keyword(s):  
Shock Wave ◽  
Static Loading ◽  
Aluminum Foam ◽  
Strain Curve ◽  
Sudden Increase ◽  
Constituent Material ◽  
Smooth Region ◽  
New Material ◽  
Casting Aluminum ◽  
Shock Tube Test

Some materials, due to their inherent properties, can be used as shock and wave absorbers. These materials include foam and porous materials, in this study, specimens were made by casting aluminum on porous mineral pumice. Which can replace aluminum foam in some applications with lesser cost, at first, the material is compared with aluminum foam using compression test and quasi-static loading diagram. Which compares the diagrams of these two materials showing the similarity of their behavior in quasi-static loading. Initially, the elastic bending of the walls causes an elastic region in the stress-strain curve of the material. Then, the plastic collapsing of the cells forms a large and relatively smooth region along the elastic and after the plastic collapse of the cells, the area known as foam densification begins where the density of the foam closer to the density of its constituent material causes a sudden increase in the stress level in the specimen. These steps have also been seen in the quasi-static loading of aluminum foam. Then, by using numerical simulations with ANSYS AUTODYN and the shock tube test the ability of these specimens were investigated to reduce the shock wave. The behavior of the material in this case is also very similar to the results of previous studies on aluminum foam.

A new type of defect structure in 124-superconducting oxide revealed by HREM

1991 ◽  
Vol 49 ◽  
pp. 1092-1093
Author(s):  
R. Sharma ◽  
B.L. Ramakrishna ◽  
N.N. Thadhani ◽  
D. Hianes ◽  
Z. Iqbal
Keyword(s):  
Shock Wave ◽  
Defect Structure ◽  
Neutron Radiation ◽  
Weak Links ◽  
Defect Structures ◽  
New Materials ◽  
New Type ◽  
Current Densities ◽  
Processing Techniques ◽  
Microstructural Studies

After materials with superconducting temperatures higher than liquid nitrogen have been prepared, more emphasis has been on increasing the current densities (Jc) of high Tc superconductors than finding new materials with higher transition temperatures. Different processing techniques i.e thin films, shock wave processing, neutron radiation etc. have been applied in order to increase Jc. Microstructural studies of compounds thus prepared have shown either a decrease in gram boundaries that act as weak-links or increase in defect structure that act as flux-pinning centers. We have studied shock wave synthesized Tl-Ba-Cu-O and shock wave processed Y-123 superconductors with somewhat different properties compared to those prepared by solid-state reaction. Here we report the defect structures observed in the shock-processed Y-124 superconductors.

Investigation of shock-wave deformation history from recovered structure

1986 ◽  
Vol 44 ◽  
pp. 434-435
Author(s):  
M.A. Mogilevsky ◽  
L.S. Bushnev
Keyword(s):  
Shock Wave ◽  
Plastic Deformation ◽  
Dislocation Density ◽  
Shock Waves ◽  
Shock Front ◽  
Single Crystals ◽  
Residual Deformation ◽  
Deformation Structure ◽  
Deformation History ◽  
Deformation Velocity

Single crystals of Al were loaded by 15 to 40 GPa shock waves at 77 K with a pulse duration of 1.0 to 0.5 μs and a residual deformation of ∼1%. The analysis of deformation structure peculiarities allows the deformation history to be re-established.After a 20 to 40 GPa loading the dislocation density in the recovered samples was about 1010 cm-2. By measuring the thickness of the 40 GPa shock front in Al, a plastic deformation velocity of 1.07 x 108 s-1 is obtained, from where the moving dislocation density at the front is 7 x 1010 cm-2. A very small part of dislocations moves during the whole time of compression, i.e. a total dislocation density at the front must be in excess of this value by one or two orders. Consequently, due to extremely high stresses, at the front there exists a very unstable structure which is rearranged later with a noticeable decrease in dislocation density.

Microstructural and fractographic characterization of B4C-Al cermets tested under dynamic and static loading

1989 ◽  
Vol 47 ◽  
pp. 562-563
Author(s):  
Gyeung Ho Kim ◽  
Mehmet Sarikaya ◽  
D. L. Milius ◽  
I. A. Aksay
Keyword(s):  
Thin Film ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
Static Loading ◽  
Carbon Deposition ◽  
Full Density ◽  
Unique Combination ◽  
Strong Component ◽  
Reaction Products

Cermets are designed to optimize the mechanical properties of ceramics (hard and strong component) and metals (ductile and tough component) into one system. However, the processing of such systems is a problem in obtaining fully dense composite without deleterious reaction products. In the lightweight (2.65 g/cc) B4C-Al cermet, many of the processing problems have been circumvented. It is now possible to process fully dense B4C-Al cermet with tailored microstructures and achieve unique combination of mechanical properties (fracture strength of over 600 MPa and fracture toughness of 12 MPa-m1/2). In this paper, microstructure and fractography of B4C-Al cermets, tested under dynamic and static loading conditions, are described.The cermet is prepared by infiltration of Al at 1150°C into partially sintered B4C compact under vacuum to full density. Fracture surface replicas were prepared by using cellulose acetate and thin-film carbon deposition. Samples were observed with a Philips 3000 at 100 kV.

Electron microscopy study of shock synthesis of silicides

1993 ◽  
Vol 51 ◽  
pp. 1162-1163
Author(s):  
Kenneth S. Vecchio
Keyword(s):  
Shock Wave ◽  
Plastic Deformation ◽  
Close Contact ◽  
Microscopy Study ◽  
High Energy ◽  
Electron Microscopy Study ◽  
Powder Materials ◽  
Porous Powder ◽  
Wave Effects ◽  
Wave Passage

Shock-induced reactions (or shock synthesis) have been studied since the 1960’s but are still poorly understood, partly due to the fact that the reaction kinetics are very fast making experimental analysis of the reaction difficult. Shock synthesis is closely related to combustion synthesis, and occurs in the same systems that undergo exothermic gasless combustion reactions. The thermite reaction (Fe2O3 + 2Al -> 2Fe + Al2O3) is prototypical of this class of reactions. The effects of shock-wave passage through porous (powder) materials are complex, because intense and non-uniform plastic deformation is coupled with the shock-wave effects. Thus, the particle interiors experience primarily the effects of shock waves, while the surfaces undergo intense plastic deformation which can often result in interfacial melting. Shock synthesis of compounds from powders is triggered by the extraordinarily high energy deposition rate at the surfaces of the powders, forcing them in close contact, activating them by introducing defects, and heating them close to or even above their melting temperatures.

1264: Predictors of Shock-Wave Lithotripsy Success for Proximal Ureteral Calculi on Non-Contrast CT?

2007 ◽  
Vol 177 (4S) ◽  
pp. 417-417
Author(s):  
Eric A. Singer ◽  
Jared D. Christensen ◽  
Susan Messing ◽  
Erdal Erturk
Keyword(s):  
Shock Wave ◽  
Shock Wave Lithotripsy ◽  
Ureteral Calculi ◽  
Contrast Ct

1108: Treatment Strategy Improves the in Vivo Stone Comminution Efficiency and Reduces Renal Tissue Injury During Shock Wave Lithotripsy

2005 ◽  
Vol 173 (4S) ◽  
pp. 300-301
Author(s):  
Michaella E. Maloney ◽  
Pei Zhong ◽  
Charles G. Marguet ◽  
Yufeng F. Zhou ◽  
Jeffrey C. Sung ◽  
...  
Keyword(s):  
Shock Wave ◽  
Treatment Strategy ◽  
Shock Wave Lithotripsy ◽  
Tissue Injury ◽  
Renal Tissue
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