DOT Tomography of the Solar Atmosphere VII. Chromospheric Response to Acoustic Events

We use synchronous movies from the Dutch Open Telescope sampling the G band, Ca?ii?H, and Hα with five-wavelength profile sampling to study the response of the chromosphere to acoustic events in the underlying photosphere. We first compare the visibility of the chromosphere in Ca?ii?H and Hα, demonstrate that studying the chromosphere requires Hα data, and summarize recent developments in understanding why this is so. We construct divergence and vorticity maps of the photospheric flow field from the G-band images and locate specific events through the appearance of bright Ca?ii?H grains. The reaction of the Hα chromosphere is diagnosed in terms of brightness and Doppler shift. We show and discuss three particular cases in detail: a regular acoustic grain marking shock excitation by granular dynamics, a persistent flasher, which probably marks magnetic-field concentration, and an exploding granule. All three appear to buffet overlying fibrils, most clearly in Dopplergrams. Although our diagnostic displays to dissect these phenomena are unprecedentedly comprehensive, adding even more information (photospheric Doppler tomography and magnetograms along with chromospheric imaging and Doppler mapping in the ultraviolet) is warranted.     

Variation of electrical conductivity in enstatite with oxygen partial pressure: Comparison of observed and predicted behavior

Oxygen partial pressure influences the electrical conductivity of enstatite because it affects the point-defect concentrations in enstatite. The behavior of the defect concentrations with P_O2 are obtained for open and partially closed conditions. On the basis of the defect variations, models for the effect of oxygen pressure on the conductivity can be constructed. The first-order models, which assume one defect type transporting all the charge, predict log(P_O2) vs. log(conductivity) slopes that are not in agreement with slopes derived from measurements on natural single crystals of enstatite. The disagreement could result from: (1) more defect species being present than the assumed charge-neutrality condition gives, or (2) the charge is transported by two or more defect types. The data suggesting the latter is the cause of the disagreement, and hence the experimentally derived activation energies must be treated carefully.     

Solubilization of Benzo(a)pyrene in Aqueous Solutions of Ionic Surfactants

The water solubility of benzopyrene in the presence of ionic detergents is investigated. The power of n-alkyl benzene sulfonates to dissolve benzopyrene in increased quantities grows with the elongation of their m-alkyl chain (from C₈ to C₁₂) and decreases with temperature between 10 and 40°C. The properties of the detergents determine their solvent effect, the substance-specific coefficient K_bind being decisive, as is demonstrated by the example of the cation-active detergents cetyltrimethylammonium bromide, sodium n-decyl benzene sulfonate and sodium lauryl sulfonate.     

Subsurface Transport of Inorganic and Organic Solutes from Experimental Road Spreading of Oil-Field Brine

A study designed to evaluate ground water quality changes resulting from spreading oil-field brine on roads for ice and dust control was conducted using a gravel roadbed that received weekly applications of brine eight times during the winter phase and 11 times during the summer phase of the study. A network of 11 monitoring wells and five pressure-vacuum lysimeters was installed to obtain ground water and soil water samples. Thirteen sets of water- quality samples were collected and analyzed for major ions, trace metals, and volatile organic compounds. Two sets of samples were taken prior to brine spreading, four sets during winter-phase spreading, five sets during summer- phase spreading, and two sets during the interim between the winter and summer phases. A brine plume delineated by elevated specific-conductance values and elevated chloride concentrations developed downgradient of the roadbed during both the winter and summer phases. The brine plume caused chloride concentrations in ground water samples to exceed U.S. EPA public drinking-water standards by two-fold during the winter phase and five-fold during the summer phase. No other major ions, trace metals, or volatile organic compounds exceeded the standards during the winter or summer phases. More than 99 percent dilution of the solutes in the brine occurred between the roadbed surface and the local ground water flow system. Further attenuation of calcium, sodium, potassium, and strontium resulted from adsorption, whereas further attenuation of benzene resulted from volatilization and adsorption.     

Analytical approximations of Arctic basin depths and their spectral analysis

Using the method of linear integral representations, analytical approximations and spectral analysis of Arctic depths are performed on the basis of a large data set. Results of calculations performed with the use of computer technologies developed by the authors are presented.