The power of jets from black holes are expected to depend on both the spin of the black hole and the structure of the accretion disk in the region of the last stable orbit. We investigate these dependencies using two different physical models for the jet power: the classical Blandford-Znajek (BZ) model and a hybrid model developed by Meier (2001). In the BZ case, the jets are powered by magneti...

We explore an accretion model for low luminosity AGN (LLAGN) that attributes the low radiative output to a low mass accretion rate, Ṁa, rather than a low radiative efficiency. In this model, electrons are assumed to drain energy from the ions as a result of collisionless plasma microinstabilities. Consequently, the accreting gas collapses to form a geometrically thin disk at small radii and is ...

Abstract We perform a full 3D general relativistic magnetohydrodynamical (GRMHD) simulation of an equal-mass, spinning, binary black hole approaching merger, surrounded by circumbinary disk and with minidisk around each hole. For this purpose, we evolve the ideal GRMHD equations on top approximated spacetime for that is valid in every position space, including horizons, during inspiral regime. ...

The outer segment portion of photoreceptor rod cells is composed of a stacked array of disk membranes. Newly formed disks are found at the base of the rod outer segment (ROS) and are relatively high in membrane cholesterol. Older disks are found at the apical tip of the ROS and are low in membrane cholesterol. Disk membranes were separated based on their membrane cholesterol content and the ext...

We report on the results of spectral fits made to a NuSTAR observation of the black hole GRS 1915+105 in a “plateau” state. This state is of special interest because it is similar to the “low/hard” state seen in other black holes, especially in that compact, steady jets are launched in this phase. The 3–79 keV bandpass of NuSTAR, and its ability to obtain moderate–resolution spectra free from d...

Using Suzaku observations of three neutron star low-mass X-ray binaries (Ser X−1, 4U 1820−30 and GX 349+2) we have found broad, asymmetric, relativistic Fe K emission lines in all three objects. These Fe K lines can be well fit by a model for lines from a relativistic accretion disk (‘diskline’), allowing a measurement of the inner radius of the accretion disk, and hence an upper limit on the n...

The paper presents the research results on electrostatic charging tendency (ECT) of transformer oil in a spinning disk system. The measurements were performed at different aging severity. Changes in static electrificationwere related to some classical aging indexes (conductivity, dissipation factor, water content, resistivity, etc.). Fast, inexpensive and reliable laboratory testing procedures ...

The mechanical response of a circularly driven disk in a dissipative medium is considered. We focus on the role played by viscous friction in the spinning motion of the disk, especially on the effect called reverse rotation, where the intrinsic and orbital rotations are antiparallel. Contrary to what happens in the frictionless case, where steady reverse rotations are possible, we find that thi...

We present Kepler light curves and optical spectroscopy of twenty X-ray bright stars located in the Kepler field of view. The stars, spectral type F-K, show evidence for rapid rotation including chromospheric activity 100 times or more above the Sun at maximum and flaring behavior in their light curves. Eighteen of our objects appear to be (sub)giants and may belong to the class of FK Com varia...

The sampling rate in most hard disk drives (HDDs) is limited by the number of servo burst sectors that have prewritten position error signal (PES) data and by the spinning speed of the HDD. This paper presents an algorithm that can generate estimates of the PES during read at high sampling rates by processing the dedicated servo burst measurements and the mean square error (MSE) path metric dat...