We review some approaches to macroscopic irreversibility from reversible microscopic dynamics, introducing the contribution of time dependent perturbations within the framework of recent developments in non-equilibrium statistical physics. We show that situations commonly assumed to violate the time reversal symmetry (presence of magnetic fields, rotating reference frames, and some time depende...

A new 4π-spectroradiometer was developed for measuring actinic flux especially under cloudy conditions based on a fixed grating imaging spectrograph and a CCDdetector leading to a simultaneous measurement of the spectrum. The new instrument incorporates a novel optical head with a 4π-field of view independent of angle of incidence. Comparisons with the actinic flux spectroradiometer of the Inst...

BACKGROUND Extraction of a broken tooth root is often a traumatic experience for both the practitioner and the patient. To extract broken roots, generally invasive approaches as open window surgeries or mucoperiosteal flap and/or removal of buccal bone are performed. PRESENTATION OF THE HYPOTHESIS Expandable micro-motor bur (EMB) is a hypothetical design of a dental instrument proposed for re...

the rotor of enegelberg whitener was equipped with a screw conveyor to reduce broken rice percentage. according to preliminary experiments this modification could reduce broken rice percentage about 2.5%. further experiment was performed to determine the effect of rotor speeds and blade positions on white rice quality. to do this, five rotor speeds, consisting 500, 600, 700, 800 and 900 r.p.m a...