The development of laser speckle metrology for the study of vibration and fluid flow

SIGLEAvailable from British Library Document Supply Centre- DSC:D80015 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

The SMA: an effective damper in civil engineering that smoothes oscillations

The properties of SMA (Shape Memory Alloys, smart materials) are associated to a first order phase transition named martensitic transformation that occurs between metastable phases: austenite and martensite. At higher temperature phase or at lower stress the austenite is the metastable phase. The martensite appears at lower temperature phase or higher stresses. The hysteresis of the transformation permits different levels of applications, i.e., in their use as a damper. Two types of applications can be considered in damping of structures in Civil Engineering. The first one is related to diminishing the damage induced by earthquakes. The second one is a reduction of oscillation amplitude associate to an increase of the lifetime for the stayed cables in bridges. Different fundamental behavior of the SMA needs to be guaranteed in each case

A method of manufacturing delta-valerolactam

Translated from Japanese (Japanese Patent 26530-1965)SIGLEAvailable from British Library Document Supply Centre- DSC:5828.4(M--50441)T / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Pre-stressed NiTi: effects of the thermodynamic forces and time

The use of NiTi in damping devices for Civil Engineering requires stable behavior of the stress-strain curves with time and cycling. In particular, the use of pre-stressed samples improves the damping efficiency. Since earthquakes can appear after several years (or decades) of calmness, it is required that the alloy maintains their properties unchanged even after long time in the pre-stressed situation. The static experimental analysis in parent phase, in phase coexistence and in martensite shows minor changes after one month at the pre-stressed condition. These changes increase when the room temperature is increased from 293 to 303 K. The study of aging at 373 K by calorimetric measurements shows relevant changes of both the R-phase and the martensitic transformation temperatures, with time constants near 70 days, in agreement with X-ray diffraction analysis. Preliminary observations associated to dynamic actions (cycling and pauses) shows that the accumulated deformation partially recovers in the pauses

On the nature of oceanic eddies shed by the Island of Gran Canaria

Publicado

Vertical distribution of meroplankton in the Antarctic Sound, Antarctica

Publicado