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Some meaningful advances have been made these last years to value precise and reliable way the residual stresses experimentally created by the autofrettage. The autofrettage process is used widely to introduce residual stresses into thick walled tubes; traditionally residual stresses have been measured using the Sachs method destructive or non-destructive methods. In this paper we describe the application of the X-rays diffraction; this technique permits to justify the presence of the compressive tangential residual stresses, and to value their distribution after two different autofrettage internal pressures loading. The results show that there is a large difference in the residual stresses find in the different autofrettege pressure. One can see the influence of the autofrettage’s pressure quantity on residual stresses created in the thickness of the test tubes.
In-depth studies of solar
flares emissions and energy releases include analyses of polarization data. Polarization
gives clear information about mechanisms and processes leading to electron acceleration
and photon production. Despite of many past attempts, the key energy range of
hard X-rays was only rarely explored and results were inconclusive. To large extend
it was due to greater instrumental complications. Currently several novel
polarimeters are either to be employed or under constructions for both balloon
and satellite based observations. The novel hard X-ray polarimeter POLAR is an
instrument developed by a collaboration between Switzerland, China and Poland.
It is primarily designed for high accuracy polarization measurements from the
prompt photon emissions of the gamma-ray bursts. The satellite orientation and
instrument pointing direction make it also capable for precise measurements of
polarization in solar flares. The instrument should fly in near future onboard
of the Chinese Space Station TG2.