The physical conditions within damped Lyα systems (DLAs) can reveal the star formation history, determine the chemical composition of the associated ISM, and hence document the first steps in the formation of present day galaxies. Here we present calculations that self-consistently determine the gas ionization, level populations (atomic fine-structure levels and rotational levels of H2), grain ...

Observations are presented showing the doublet C ivλλ1548, 1551 absorption lines superimposed on the C iv emission in the radio galaxy 0943–242. Within the errors, the redshift of the absorption system that has a column density of NCIV = 1014.5±0.1 cm−2 coincides with that of the deep Lyα absorption trough observed by Röttgering et al. (1995). The gas seen in absorption has a resolved spatial e...

Observations of the C iv and Mg ii absorption lines in the Seyfert 1 galaxy NGC 4151 obtained with the GHRS in October 1994 are presented. The data from the STScI archive show multiple broad and narrow components in both species. In addition to Galactic absorption, four narrow and four broad systems associated with NGC 4151 are identified. Two broad systems dominate the total equivalent width, ...

The main objective of this paper is to examine the effect of nanomaterials on mass transfer coefficient in bubble type absorption of carbon dioxide by experiment. The absorption process is carried out in a bubble column and in room temperature. Mass transfer coefficient, saturated concentration of CO2, and gas holdup are determined in this system. The kinds of nanomaterials, the concentrations ...

This paper deals with an absorption spectroscopic method for trace gas measurements called DOAS (Diierential Optical Absorption Spectroscopy) from a statistical point of view. The DOAS technique is an absorption spectrosco-pic technique to measure trace gas concentrations. It is capable of detecting and measuring a number of important trace gases at tropospheric concentration levels by observin...

Nitrogen dioxide (NO2) is a ubiquitous, pollutant gas that produces a broad range of pathological and physiological effects on the lung. Absorption of inhaled NO2 is coupled to near-interfacial reactions between the solute gas and constituents of the airway and alveolar epithelial lining fluid. Although alveolar surfactant imparts limited resistance to respiratory gas exchange compared with tha...

We calculate the neutral hydrogen column density of self-absorption in QSOs predicted in a model where the QSOs are located in the same halos that contain the gas in damped Lyα absorption systems. The model is parameterized by the probability P0 that any halo has an active QSO. We assume that the QSOs ionize the gas, but do not expel or heat it. The derived H I column densities produce negligib...

ORFEUS far UV echelle spectra have been used to investigate H I, H2 and CO absorption lines along the line of sight towards LH 10:3120 in the LMC, extending the study presented by de Boer et al. (1998). While H2 absorption is clearly visible, no CO absorption at LMC velocities is detected, but an upper limit of N(CO) ≤ 3.3 × 10 cm for the CO column density is derived for the C-X band near 1088 ...

This paper addresses the problem of reconstructing the 3D structure of planetary nebulae from 2D observations. Assuming axial symmetry, our method jointly reconstructs the distribution of dust and ionized gas in the nebulae from observations at two different wavelengths. In an inverse rendering framework we optimize for the emission and absorption densities which are correlated to the gas and d...