The Sloan Digital Sky Survey can be used to detect and characterize red and reddened quasars. In Richards et al. (2003), we showed that 6% of SDSS quasars have red colors consistent with significant dust reddening by an extinction curve similar to that of the Small Magellanic Cloud (SMC). We estimate that a further 10% of the luminous quasar population is missing from our magnitude-limited SDSS...

Compared to starburst galaxies, normal star forming galaxies have been shown to display a much larger dispersion of the dust attenuation at fixed reddening through studies of the IRX-β diagram (the IR/UV ratio “IRX” versus the UV color “β”). To investigate the causes of this larger dispersion and attempt to isolate second parameters, we have used GALEX UV, ground-based optical, and Spitzer infr...

in order to compare sampling efficiencies of total and inhalable dust methods, three airborne dust sampling systems , 7-hole sampler , close and open face filter cassette were compared side-by-side , as stationary and for the personal samplers , in a wood working industry to evaluate their relative efficiency. a total of 162 samples were collected. the study of particle size distribution by cas...

cement dust exposure is associated with increased respiratory impairment. as the major occupational hazard in the cement production industry is cement particles, our aim was to more thoroughly examine the acute effects of occupational exposure to cement dust on the respiratory system. a cross-shift study was conducted in a cement factory in iran. 100 high exposed workers from production and pac...

Introduction: Magnesium rich amorphous silicates are major component of dust in the interstellar medium. At the birth of stars, when the ISM cloud collapses, dusts are incorporated in the forming disk. Temperature progressively increases along the disk when approaching the inner regions [1,2,3]. So they were subjected to various temperature conditions for long periods as they travel along the d...

We are working on a spectroscopic survey of an unbiased, extinction-limited sample of candidate young stars in the Rho Ophiuchi. While infrared, X-ray and optical surveys of the cloud have identified many young stellar objects (YSOs), these surveys yield little or no information on the YSOs’ ages and masses and are biased towards particular stages of stellar evolution. The goals of our study ar...

We have observed a quiescent small globule, the Thumbprint Nebula, with the ISOPHOT far-infrared camera at 100 and 200μm. The observed emission is optically thin thermal emission from dust at a temperature of ∼14–16 K. The energy budget of the cloud is studied by considering the energy input (interstellar radiation field, ISRF), and outputs (scattered and emitted radiation). It is found that th...

Supplemental water sprays were placed along the sides of a continuous mining machine to improve suppression and confinement of the dust cloud under the cutting boom to reduce downwind dust levels. Using a full-scale mock-up of a continuous mining machine, preliminary work showed that these side sprays improved suppression of the dust cloud and redistributed this cloud under the cutting head. Th...