When helicopters operate close to the ground in desert conditions, the rotor wake can entrain large amounts of dust into the flow field surrounding the aircraft. This entrainment of dust can result in the potentially dangerous condition known as brownout where the pilot loses situational awareness. Understanding the physics that governs the entrainment of dust from the ground may eventually all...

Measurements of the charge of dust grains have been performed in a quasineutral plasma over a wide range of grain sizes. A new method was established for measuring the charge on grains levitating in the striations of a dc glow discharge. A single dust particle is moved out of a dust cloud with the help of a focused laser beam. When it leaves the beam it returns back to the cloud, and the charge...

Using far-infrared emission maps taken by IRAS and Spitzer and a near-infrared extinction map derived from 2MASS data, we have made dust temperature and column density maps of the Perseus molecular cloud. We show that the emission from transiently heated very small grains (VSGs) and the big grain dust emissivity vary as a function of extinction and dust temperature, with higher dust emissivitie...

We investigate the dust associated with the supernova remnant (SNR) N49 in the Large Magellanic Cloud (LMC) as observed with the Herschel Space Observatory. N49 is unusually bright because of an interaction with a molecular cloud along its eastern edge. We have used PACS and SPIRE to measure the far IR flux densities of the entire SNR and of a bright region on the eastern edge of the SNR where ...

We present a full sky 100m map that is a reprocessed composite of the COBE/DIRBE and IRAS/ISSA maps, with the zodiacal foreground and connrmed point sources removed. Before using the ISSA maps, we remove the remaining artifacts from the IRAS scan pattern. Using the DIRBE 100m and 240m data, we have constructed a map of the dust temperature, so that the 100m map may be converted to a map proport...

Abstract. There have been numerous recent publications showing that mineral dust might be a good absorber for solar radiation in addition to its capability to act as cloud condensation nuclei (CCN) and ice forming nuclei (IFN), and could lead to reduced cloud cover and precipitation in the region where it is present. This effect is investigated using a dynamic cloud model with detailed microphy...

The exquisite angular resolution available with Chandra should allow precision measurements of faint diffuse emission surrounding bright sources, such as the X-ray scattering halos created by interstellar dust. However, the ACIS CCDs suffer from pileup when observing bright sources, and this creates difficulties when trying to extract the scattered halo near the source. The initial study of the...