Distribution Of Minor Constituents Research Articles

Moist Adiabats with Multiple Condensing Species: A New Theory with Application to Giant-Planet Atmospheres

AbstractA new formula is derived for calculating the moist adiabatic temperature profile of an atmosphere consisting of ideal gases with multiple condensing species. This expression unifies various formulas published in the literature and can be generalized to account for chemical reactions. Unlike previous methods, it converges to machine precision independent of mesh size. It accounts for any ratio of condensable vapors to dry gas, from zero to infinity, and for variable heat capacities as a function of temperature. Because the derivation is generic, the new formula is not only applicable to planetary atmospheres in the solar system but also to hot Jupiters and brown dwarfs in which a variety of alkali metals, silicates, and exotic materials condense. It is demonstrated that even though the vapors are ideal gases, they interact in their effects on the moist adiabatic lapse rate. Finally, the authors apply the new thermodynamic model to study the effects of downdrafts on the distribution of minor constituents and the thermal profile in the Galileo probe hot spot. The authors find that the Galileo probe measurements can be interpreted as a strong downdraft that displaces an air parcel from the 1-bar to the 4-bar level (1 bar = 100 000 Pa).

On the Relationship between Temperature-types of Deposits and Distribution of Minor Constituents in Sulfide Minerals

On the Relationship between Temperature-types of Deposits and Distribution of Minor Constituents in Sulfide Minerals

Effect of genetic modification on the distribution of minor constituents in canola oil

AbstractOil derived from different lines of genetically modified canola varieties was analyzed for phospholipids, tocopherols, and phytosterols by various chromatographic techniques. As observed previously in genetically modified soybean oils, there was a decrease in the content and composition of phosphatidic acid in three of the modified canola oils derived from the 12 varieties investigated. Normal‐phase high‐performance liquid chromatographic (HPLC) analyses showed small variations in the phospholipid content of major classes, despite few differences in their composition. Reversed‐phase HPLC data indicated that the molecular species distribution of phosphatidylethanolamine was significantly altered by genetic modification when compared to phosphatidylcholine. Impact of oilseed modification on the tocopherol content was variable, with greater variation in the concentration of α‐ and γ‐tocopherols than δ‐tocopherol. Phytosterol composition was markedly affected by genetic modification. Brassicasterol, campesterol, and β‐sitosterol levels were consistently lowered in one genotype, whereas increased brassicasterol content was observed in the other variety. In general, genetic modification of canola seeds led to changes in the distribution of phospholipids, tocopherols, and phytosterols.

Distribution of minor constituents in a thermal interface

A non-steady, two-dimensional, compressible mathematical model of a fluid with constant viscosity and thermal conductivity is given in order to represent a thin atmospheric layer located at 60 km height, as a function of a known initial vertical distribution of temperature, chemical concentrations of minor components and assumed free boundary conditions. The purpose of this paper is to determine the influence of convective laminar processes in the vertical distribution of minor constituents in a thermal interface. Only three minor components are considered, atomic oxygen, molecular oxygen and ozone. Numerical solutions of the stated timedependent convection problem for different Rayleigh numbers show a marked influence of the established flow pattern upon the distribution of minor constituents. In all cases, an enhancement of mean concentration gradients in relatively small regions adjacent to the warmer and colder boundaries was observed.

Latitudinal distributions of minor neutral hydrogen-oxygen constituents in the winter mesosphere and lower thermosphere

The latitudinal distributions of the concentrations of hydrogen-oxygen constituents are computed in the winter mesosphere and lower thermosphere. Vertical eddy diffusion coefficients varying with latitude and altitude are used, but the effects of horizontal transport are not included. The results show that the distributions of minor constituents have significant latitudinal variations due to the effects of photodissociation and vertical diffusion. It is also indicated that the meridional profile of the O ( 3 P) concentration has a maximum in the latitudes 50°–60° near the mesopause in winter, and that the vertical profile of the O 3 concentration has a second peak near the mesopause, mainly caused by the indirect influences of vertical eddy diffusion. The calculated profiles of the O( 3 P) and O 3 concentrations, the atomic-to-molecular oxygen concentration ratios, and airglow emission rates are compared with the recent available observations, showing fairly good agreement. Comparison of the theoretical O( 3 P) concentrations and 5577 Å airglow emissions suggests an important role of horizontal transport in the lower thermosphere.

The Dissolution of Steel in the System NH 4 NO 3 ‐ NH 3 ‐ H 2 O

Rates ranged from near zero to almost 30,000 mdd at 30°C depending on the type of steel used. No cracking or pitting was observed. This variation did not correlate effectively with grain size or roughness factor, but may be related either to the amount or distribution of minor constituents in the steel. Both mechanical stress and quenching from 1000°C increased the dissolution rate. The reduction reaction was in part, if not wholly, nitrate to nitrite. The corrosion product was nonprotective and often nonadherent and appeared to be a hydrated or ammoniated iron (11) hydroxide.