1,721,168 research outputs found
TeraHertz Phonons and Piezonuclear Reactions from Nano-scale Mechanical Instabilities
No full textTeraHertz phonons are produced in condensed matter by mechanical instabilities at the nano-scale (fracture, turbulence, buckling). They present a frequency that is close to the resonance frequency of the atomic lattices and an energy that is close to that of thermal neutrons. A series of fracture experiments on natural rocks has recently demonstrated that the TeraHertz phonons are able to induce fission reactions on medium weight elements with neutron and/or alpha particle emissions. The same phenomenon appears to have occurred in several different situations and to explain puzzles related to the history of our planet, like the ocean formation or the primordial carbon pollution, as well as scientific mysteries, like the so-called "cold nuclear fusion" or the correct radio-carbon dating of organic materials. Very important applications to earthquake precursors, climate change, energy production, and cell biology can not be exclude
Effetto delle tamponature nelle strutture intelaiate sottoposte a sollecitazione sismica
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Lateral loading distribution between the elements of a three-dimensional civil structure
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Is the shroud of turin in relation to the old jerusalem historical earthquake?
No full textPhillips and Hedges suggested, in the scientific magazine Nature (1989), that neutron radiation could be liable of a wrong radiocarbon dating, while proton radiation could be responsible of the Shroud body image formation. On the other hand, no plausible physical reason has been proposed so far to explain the radiation source origin, and its effects on the linen fibres. However, some recent studies, carried out by the first author and his Team at the Laboratory of Fracture Mechanics of the Politecnico di Torino, found that it is possible to generate neutron emissions from very brittle rock specimens in compression through piezonuclear fission reactions. Analogously, neutron flux increments, in correspondence to seismic activity, should be a result of the same reactions. A group of Russian scientists measured a neutron flux exceeding the background level by three orders of magnitude in correspondence to rather appreciable earthquakes (4th degree in Richter Scale). The authors consider the possibility that neutron emissions by earthquakes could have induced the image formation on Shroud linen fibres, trough thermal neutron capture by Nitrogen nuclei, and provided a wrong radiocarbon dating due to an increment in C14, 6, content. Let us consider that, although the calculated integral flux of 10^13 neutrons per square centimetre is 10 times greater than the cancer therapy dose, nevertheless it is 100 times smaller than the lethal dos
An experimental compliance calibration strategy for estimating the elastic interface constants of delamination test specimens
No full textThe delamination of composite laminates can be effectively modelled by considering a delaminated laminate as an assemblage of sublaminates connected by an elastic interlaminar interface. In this context, the question arises on the values to be assigned to the elastic interface constants. In the present study, we show how the elastic interface constants can be estimated through an experimental compliance calibration strategy. The method is based on the analytical solution for the MMB test, derived in a previous study. Here, a nonlinear least squares fitting procedure is applied to obtain the values of the elastic interface constants from the experimental results of DCB and ENF tests. Preliminary experimental tests have been conducted to check the effectiveness of the proposed strategy
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