We provide necessary and sufficient conditions for admissible transformations in the projectivised dual quaternion model of rigid body displacements and we characterise constraint varieties of dyads with revolute and prismatic joints in this model. Projective transformations induced by coordinate changes in moving and/or fixed frame fix the quadrics of a pencil and preserve the two families of ...

lateral and anterior displacements of mandible may cause malocclusion. the aim of this study was to determine the prevalence of these displacements in a population of 597 childrens age 12 in mashhad secondary schools. displacment of mandible was shown to be in 11.8 percent of the population (6.2 percent anterior and 5.6 percent lateral displacement).anterior displacement of mandible was diagnos...

We investigate the feasibility of detecting fires in subsurface coal deposits through InSAR observations of accompanying surface displacements. Uncontrolled burning of subsurface coal seams have been reported from many locations around the world. In northern China alone, more than 10 Million tons (Mt) of coal are estimated to burn every year. This has massive implications for the regional econo...

Since 1990 the project ‘Climate Change in the Arid Andes’ has been focusing on past climate and environmental conditions in the high mountain range of the north Chilean Andes (18 S– 28 S). The extreme aridity of this region is shown by the absence of glaciers, even at the highest altitudes above 6700 m a.s.l. More knowledge of the present climatic situation is needed to interpret the proxy data...

Motivated by recent experiments, we have performed simulations which show in detail how the electrons and ions in GaAs respond to fast intense laser pulses ~with durations of order 100 fs and intensities of order 1210 TW/cm). The method of tight-binding electron-ion dynamics is used, in which an arbitrarily strong radiation field is included through a time-dependent Peierls substitution. The po...

In a system with hysteresis, the system response lags the excitation [16, 21] — for any excitation [10]. Hysteretic behavior is commonly depicted as loops in graphs (2D plots) of periodic (oscillatory) output vs. periodic input. In rate-dependent hysteresis, the size and shape of the hysteresis loop changes with the rate or frequency of the input. If the loop collapses to a function (e.g., a cu...

Displacements around a tunnel, occurring as a result of excavation, consist of the elastic and plastic parts. In this paper, we discuss the elastic part of displacements as a result of excavation, called net displacement. In general, the previous analytical solutions presented for determining the displacements around a circular tunnel in an elastic medium do not give the net displacements...