The Joule–Thomson expansion is studied for Reissner–Nordström-Anti-de Sitter black holes with cloud of strings and quintessence, as well its thermodynamics. cosmological constant treated thermodynamic pressure, whose conjugate variable considered the volume. characteristics are in four main aspects case ω=−1 ω=−23, including coefficient, inversion curves, isenthalpic curves ratio between minimu...

We use ROSAT PSPC data to study the X-ray properties of a sample of twelve poor groups that have extensive membership information (Zabludoff & Mulchaey 1997; Paper I). Diffuse X-ray emission is detected in nine of these groups. In all but one of the X-ray detected groups, the X-ray emission is centered on a luminous elliptical galaxy. Fits to the surface brightness profiles of the X-ray emissio...

In this paper hydrographic observations made over a fringing coral reef at the northern end of the Gulf of Aqaba near Eilat, Israel, are discussed. These data show exchange flows driven by the onshore–offshore temperature gradients that develop because shallow regions near shore experience larger temperature changes than do deeper regions offshore when subjected to the same rate of heating or c...

Accumulating observational evidence for a number of radio galaxies suggests an association between their jets and regions of active star formation. The standard picture is that shocks generated by the jet propagate through an inhomogeneous medium and trigger the collapse of overdense clouds, which then become active star-forming regions. In this contribution, we report on recent hydrodynamic si...

We report on Keck optical BVRI images and spectroscopy of the companion of the binary millisecond pulsar PSR J0218+4232. A faint bluish (V = 24.2, B − V = 0.25) counterpart is observed at the pulsar location. Spectra of this counterpart reveal Balmer lines which confirm that the companion is a Helium–core white dwarf. We find that the white dwarf has a temperature of Teff = 8060 ± 150 K. Unfort...

Based on the hypothesis that reclaimed water for irrigating is the cardinal source of heavy metals pollution in soil, and the heavy metals leave from soil mainly by plant harvest, the article constructs a differential equation and simulates the cumulation of Cd in wheat soil of southeast suburb in Beijing based on simulink of matlab. With the data relative Cd mass proportion in soil as predicto...

The evolution of white dwarfs can be described as a simple cooling process. Recently, it has been possible to determine with an unprecedented precision their luminosity function, that is, the number of stars per unit volume and luminosity interval. Since the shape of the bright branch of this function is only sensitive to the average cooling rate, we use this property to check the possible exis...