scholarly journals Solid matter with zero shear modulus in flat universe

Author(s):  
Peter Mészáros
2015 ◽  
Vol 24 (08) ◽  
pp. 1550063 ◽  
Author(s):  
Matej Škovran

We construct explicit solutions for scalar, vector and tensor perturbations in a less known setting, a flat universe filled by an isotropic elastic solid with pressure and shear modulus proportional to energy density. The solutions generalize the well-known formulas for cosmological perturbations in a universe filled by ideal fluid.


2016 ◽  
pp. 3524-3528
Author(s):  
Casey Ray McMahon

In this paper, I discuss the theory behind the use of a dense, concentrated neutron particle-based beam. I look at the particle based physics behind such a beam, when it is focused against solid material matter. Although this idea is still only theoretical, it appears that such a beam may be capable of disrupting the stability of the atoms within solid matter- in some cases by passing great volumes of neutrons between the electron and nucleus thus effectively “shielding” the electron from the charge of the nucleus. In other cases, by disrupting the nucleus by firing neutrons into it, disrupting the nucleus and weakening its bond on electrons. In either case- the resulting effect would be a disruption of the atom, which in the case of material matter would cause said material matter to fail, which would appear to the observer as liquification with some plasma generation. Thus, a dense neutron particle based beam could be used to effectively liquefy material matter. Such a beam could bore through rock, metal, or even thick, military grade armour, like that used on tanks- causing such materials to rapidly liquefy. The denser and thicker the neutron beam, the more devastating the effect of the beam- thus the faster material matter will liquefy and the greater the area of liquification. Such a beam would have applications in Defence, mining and drilling operations.


1993 ◽  
Vol 58 (11) ◽  
pp. 2642-2650 ◽  
Author(s):  
Zdeněk Kruliš ◽  
Ivan Fortelný ◽  
Josef Kovář

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.


2014 ◽  
Vol 216 ◽  
pp. 151-156 ◽  
Author(s):  
Liviu Bereteu ◽  
Mircea Vodǎ ◽  
Gheorghe Drăgănescu

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.


Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2743
Author(s):  
Seongnoh Ahn ◽  
Jae-Eun Ryou ◽  
Kwangkuk Ahn ◽  
Changho Lee ◽  
Jun-Dae Lee ◽  
...  

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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