Digital Commons Network^™

Absorption And Fluorescence Spectra Of Sodium In An Argon Matrix, Alan Bruce Tutein

Doctoral Dissertations

A computer simulation of the formation of trapping sites for sodium atoms trapped in a solid argon matrix has been performed, using experimentally determined argon-argon and sodium-argon potentials available in the literature. The simulation method is a greatly simplified version of the more time-consuming molecular dynamics approach. Optical absorption and emission spectra corresponding to the matrix-perturbed 3s-3p sodium transition were calculated for each simulated trapping site, using first-order perturbation theory and the available sodium-argon dimer potentials. Two of the three requisite sodium-argon dimer potentials, the X$\sp2\Sigma$ and the A$\sp2\Pi,$ have been determined experimentally, but for the B$\sp2\Sigma$ potential, only a …

Impact Of Land-Use And Climatic Changes On Hydrology Of The Himalayan Basin: A Case Study Of The Kosi Basin, Keshav Prasad Sharma

Doctoral Dissertations

Land-use and climatic changes are of major concern in the Himalayan region because of their potential impacts on a predominantly agriculture-based economy and a regional hydrology dominated by strong seasonality. Such concerns are not limited to any particular basin but exist throughout the region including the downstream plain areas. As a representative basin of the Himalayas, we studied the Kosi basin (54,000 km$\sp2)$ located in the mountainous area of the central Himalayan region. We analyzed climatic and hydrologic information to assess the impacts of existing and potential future land-use and climatic changes over the basin.

The assessment of anthropogenic inputs …

An Analysis Of High Frequency Methane Measurements In Central New England, Mark Charles Shipham

Doctoral Dissertations

A unique high resolution ambient air methane data set consisting of approximately 125,000 independently measured data points for the years 1991-1995 has been collected at a site in the northeastern United States. This data base is used to examine the long term trend, seasonal and diurnal cycles, and the frequent pollution events that affect the site on a year round basis.

The annual median mixing ratio of methane for all measurements was 1808 ppbv in 1992, increasing at a variable rate to 1837 ppbv in 1995. The lower 10-30% of the data from each month was defined as representative of …

The Chemistry And Dry Deposition Of Atmospheric Nitrogen At A Rural Site In The Northeastern United States, Barry Lee Lefer

Doctoral Dissertations

Measurements of N gas (HNO$\sb3$, NH$\sb3$) and aerosol (NO$\sb3\sp-,$ NH$\sb4\sp+$) species were made between 1991-1995 to examine the nature of atmospheric N chemistry and to estimate the importance of N dry deposition to the Harvard Forest (Petersham, MA). This U.S. site was influenced by aged rural air masses advected from the northwest (NW) and fresh industrial emissions from the southwest (SW). Mean midday HNO$\sb3$ and aerosol N mixing ratios were four times higher in SW surface winds.

Diel cycles provided evidence of the entrainment of HNO$\sb3$ and aerosol NO$\sb3\sp-$ from aloft as the nocturnal inversion broke down. HNO$\sb3$ made up …

Response Of Outer Radiation Belt Electrons To A Magnetic Storm, Donald Hugh Brautigam

Doctoral Dissertations

To advance our understanding of the magnetic storm dynamics of the outer radiation belt relativistic electrons, the magnetic storm which commenced on 9 October 1990 was analyzed in detail using data from the Combined Release and Radiation Effects Satellite (CRRES) and the Los Alamos National Laboratory geosynchronous satellite 1989enspace 046. Electron differential flux was transformed into phase space density as a function of the three adiabatic invariants. The invariants were determined by magnetic field data from CRRES and the Tsyganenko 1989 Kp driven model. The unique work of this thesis is the storm time radial diffusion modeling performed using time …