Vortex motion of the dust in a dusty plasma is shown to result because non-parallelism of the ion density gradient and the gradient of the magnitude of the ion ambipolar velocity cause the ion drag force on dust grains to be non-conservative. Dust grain poloidal vortices consistent with the model predictions are experimentally observed, and the vortices change character with imposed changes in ...

We report the first resolved scattered light images of the circumstellar dust disk around the old Pre-Main Sequence star HD141569A. The disk seen in HST/NICMOS2 images shapes a bright annulus inclined at 37.5±4.5 from edge-on. This ring peaks at 325±10AU from the star with a characteristic width of ∼ 150AU. At 1.6μm, the dust grains scatter a total flux density of at least 4.5±0.5mJy. Our disk ...

It is simulated the non-linear one-dimensional sheaths with dust particles of the given size, density and profile in an oblique magnetic field, using the modified PIC method with self-consistent dust particle charge. The Coulomb scattering and the collection of electrons and ions by dust particles are simulated by the Monte-Carlo method with 3D velocity distribution functions for electrons and ...

We investigated the cause of optical transmittance degradation in tapered fibers. Degradation commences immediately after fabrication and it eventually reduces the transmittance to almost zero. It is a major problem that limits applications of tapered fibers. We systematically investigated the effect of the dust-particle density and the humidity on the degradation dynamics. The results clearly ...

In self-similar fragmentations with a negative index, fragments split even faster as their mass is smaller, so that the fragmentation runs away and some mass is reduced to dust. Our purpose is to investigate the regularity of this formation of dust. Let M(t) denote the mass of dust at time t.We give some sufficient and some necessary conditions for the measure dM to be absolutely continuous. In...

We present the results of 1.3mm dust continuum observations for a sample of 17 X-ray selected TTauri stars in the Ophiuchus star forming region performed with the MPIfR 7-channel bolometer arraymounted at the IRAM30mMillimeter Radio Telescope. We have detected cold dust emission from 3 of the objects and have derived 3σ upper limits (∼ 21mJy on average) for the remaining objects. These upper li...

as surfactants enhance the membrane transport of organic compounds, it has to be assumed that they decisively influence the absorption of pollutants from house dust. sampling sites for the surfactant analysis include housing areas, each location of which has different surroundings such as rural, urban, construction, and industrial area. three stations had been selected for each housing area and...

We have considered the thermal equilibrium in pre-protostellar cores in the approximation where the dust temperature is independent of interactions with the gas and where the gas is heated both by collisions with dust grains and ionization by cosmic rays. We have then used these results to study the stability of cores in hydrostatic equilibrium in the limit where thermal pressure dominates over...