We present spectroscopic observations of the damped Lyα absorber at redshift z = 1.9342 seen in the spectrum of the quasar Q0151+048A. The redshift of the absorber is greater than the redshift of the quasar, so the system resembles the zabs ≈ zem damped absorber at z = 2.81 towards the quasar PKS0528-250. We have previously reported the detection of Lyα emission from the latter absorber, one of...

Linear passive vibration absorbers, such as tuned mass dampers, often contain springs, dampers and masses, although recently there has been a growing trend to employ or supplement the mass elements with inerters. When considering possible configurations with these elements broadly, two approaches are normally used: one structure-based and one immittance-based. Both approaches have their advanta...

We compare three different approaches to high-resolution contact lithography with special emphasis on contrast mechanisms for subwavelength structures. Masks with protruding metal absorbers, masks with absorbers embedded in the transparent background, and masks with air gaps and recessed absorbers are studied. Using the Green’s tensor technique we compute the light intensity distribution in the...

In this work, a system consisting of a main structure with a nonlinear tuned vibration absorber having a hardening spring attached to it is considered. The nonlinearity in the absorber's spring is a cubic nonlinearity and is obtained by attaching two additional, relatively soft, similar linear springs to the absorber's mass. These added springs are attached to the absorber's mass in such a way ...

In this paper, the bursting oscillation phenomenon in coupled systems with two time scales is introduced. Firstly, several types of bifurcation are briefly introduced: fold bifurcation, Hopf limit cycle homoclinic etc. The oscillations system excitation terms and delay considered. Secondly, some simple introduced, such as fold/fold bursting, fold/supHopf subHopf/subHopf fold/LPC Hopf/LPC fold/h...

Formulas for the optimal design of single-degree-of-freedom (SDOF) tuned-mass dampers (or dynamic vibration absorbers) for SDOF structures under random and harmonic excitations have been available for many years. Whenever an absorber body is attached to a primary system, there is potential for utilization of motion in more than one degree of freedom of the body relative to the primary system. I...

We describe recent discoveries of low column density (NHI ≤ 10 cm) H I Lyα absorbers made with the Hubble Space Telescope (HST) which have allowed us a first look at gas in local intergalactic space between us and the “Great Wall”. Despite the mere 2.4m aperture of HST, these new observations allow us to detect absorbers with column densities, NHI ≈ 10 12.5 cm, as low as those found using Keck/...