We review some of the main physical and statistical properties of the X-ray absorber in AGNs. In particular, we review the distribution of the absorbing column density inferred from X-ray observations of various AGN samples. We discuss the location of the X-ray absorber and the relation with the dust absorption at optical and infrared wavelengths. Finally, we shortly review the recent findings ...

Car body lightening and crashworthiness are two important objectives of car design. Due to their excellent performance, composite materials are extensively used in the car industries. In addition, reducing the weight of vehicle is effective in decreasing the fuel consumption. Hat shape energy absorber is used in car’s doors for side impact protection. The aim of these numerical models and expe...

We present XMM-Newton observations of the AGN SDSS 1430-0011. The low S/N spectrum of this source obtained in a snap shot Chandra observation showed an unusually flat continuum. With the follow up XMM-Newton observations we find that the source spectrum is complex; it either has an ionized absorber or a partially covering absorber. The underlying power-law is in the normal range observed for AG...

An efficient resolution for ultrathin metamaterial perfect absorber (MPA) is proposed and demonstrated in the VHF radio band (30-300 MHz). By adjusting the lumped capacitors and the through vertical interconnects, the absorber is miniaturized to be only λ/816 and λ/84 for its thickness and periodicity with respect to the operating wavelength (at 102 MHz), respectively. The detailed simulation a...

We report the results of XMM-Newton observations of the X-ray bright, radio-loud blazar GB B1428+4217 at a redshift of z = 4.72. We confirm the presence of soft X-ray spectral flattening at energies . 0.7 keV as reported in previous ROSAT and BeppoSAX observations. At hard X-ray energies the spectrum is consistent with a power-law although we find the spectral slope varied between both XMM-Newt...

X-ray spectroscopy of Seyfert 1 galaxies often reveal absorption edges resulting from photoionized gas along the line-of-sight to the central engine, the so-called warm absorber. I discuss how recent ASCA observations of warm absorber variability in MCG−6-30-15 can lead us to reject a one-zone model and, instead, have suggested a multi-zone warm absorber. The evidence for dust within the warm a...

We present a theory of perfect absorption in a bilayer model composed of a mu-near-zero (MNZ) metamaterial (MM) absorbing layer on a metallic substrate. Our analytical solutions reveal that a MM layer with a large purely imaginary permeability and a moderate permittivity backed by a metallic plane has a zero reflection at normal incidence when the thickness is ultrathin. The impedance-mismatche...

In this paper, different semi-active control strategies for non-linear quarter car model equipped with controllable magneto-rheological (MR) shock absorbers and fuzzy logic controller are compared. Polynomial model is selected to characterize the experimental results of MR shock absorber. A combination of Forward Fuzzy Logic Controller (FFLC) and Inverse Fuzzy Logic Controller (IFLC) is designe...

Future experiments to probe the Cosmic Microwave Background (CMB) polarization will need arrays of 1000s of sensitive bolometers. We are developing a Transition-edge Hot-electron Microbolometer (THM) to fill this need. This small-volume bolometer consists of a superconducting bilayer Transition-Edge Sensor (TES) with a thin-film absorber. Unlike traditional monolithic bolometers which make use ...

Finite settling time control of the double integrator is considered. The approach taken is to design a compensator based on a virtual lossless absorber which is tuned so that, at some predetermined time, the virtual subsystem possesses all of the system’s energy. At this time the controller is turned off, and the double integrator remains at rest at the origin. This strategy gives the appearanc...