Sample records for biogeokhimicheskikh tsiklov makro

  1. Makro- and micromorphological evidence of processes taking place during Albeluvisol development in S Norway

    NASA Astrophysics Data System (ADS)

    Sauer, Daniela; Schülli-Maurer, Isabelle; Sperstad, Ragnhild; Sørensen, Rolf


    We studied two soil chronosequences in S Norway to identify processes involved in Albeluvisol formation. For this purpose, field observation of vertical and horizontal sections of soil profiles, soil chemical and mineralogical analyses were carried out, and in particular, micromorphological analysis was applied. The study area is located at the western and eastern side of the Oslofjord, S Norway, in the counties Vestfold and Østfold. This region is characterized by continuous glacio-isostatic uplift over the entire Holocene. Hence, the age of the land surface continuously increases from the coast towards higher elevations. Twelve soil profiles in loamy marine sediments were studied. Based on macro- and micromorphological observations and analytical data progressive soil formation is characterized as follows: As soon as the land surface is raised above sea level, five major processes are initiated: 1) development of deep desiccation cracks, forming a polygonal pattern; 2) compaction, taking place as soon as the coarse pores have been drained; 3) pyrite oxidation and release of sulfuric acid; 4) carbonate dissolution by acids from pyrite and iron oxidation resulting in rapid decarbonatization of the originally calcareous sediments; 5) precipitation of iron hypocoatings and coatings in the capillary fringe Soon after these very early processes have taken place, limited water permeability of the fine-textured sediments leads to horizon differentiation into Ah, Eg and Btg horizons within less than 2.1 ka. Eg horizons become lighter in colour with time. Also illuvial clay is already observed in the 2.1 ka-old soil. Soil pH in the upper part of the E horizon of this soil is already too low for significant clay mobilization. Clay illuviation is still active in all soils studied, but the upper boundary of the zone where pH favours clay mobilization is at 20-50 cm depth. Progressive clay illuviation over time is recorded in increasing thickness of clay coatings and proportion of voids having clay coatings. Clay mobilization and iron co-eluviation in the upper Eg horizon ceases within less than 2.1 ka, whereas weathering and formation of clay minerals and iron oxides continue, leading to formation of a BE horizon in the upper part of the Eg horizon. Albeluvic tongues start to form after 4.6-6.2 ka, developing preferably along desiccation cracks. Albeluvic material is washed into the cracks, and also enhanced leaching of bases and clay eluviation take place in the cracks. As both processes proceed, the albeluvic tongues get longer and wider. Clayey intercalations occur in the older soils (Stagnic Albeluvisols), and the following concept is suggested to explain their genesis: When after snow melt or a rainy period infiltrating water arrives at the lower end of an albeluvic tongue, the tongue fills up with water. Perched water accumulates also on top of the dense Btg horizon. Water, carrying suspended clay, penetrates under the pressure of the overlying water column from the tongue into the Btg horizon, where additional clay is mobilized. The clay settles when the velocity of the water decreases, forming clayey intercalations in the dense matrix of the Btg horizon.

  2. [Calculation of flammability limits of gas phases with ethylene oxide in sterilisers].


    Askar, Enis; Schröder, Volkmar; Acikalin, Aydan; Steinbach, Jörg


    A calculation method for flammability limits of gas phases with ethylene oxide in sterilisers was developed. Using the Software GasEq and the newly developed Makro "SterEx" for MS-Excel, flammability limits of mixtures with ethylene oxide, air and inert gases at temperatures between 20 degrees C and 100 degrees C and pressures between 0.4 bar and 1.0 bar can be calculated. This method can be used to easily determine safe operating conditions. The used semi-empirical model is based upon the assumption of constant flame temperature profiles at the flammability limits subject to the EO-concentration for different mixtures. To collect model parameters and to validate the model, several experiments with mixtures of ethylene oxide, nitrogen, carbon dioxide, water vapour and air were carried out to determine flammability limits. To simulate the structural conditions of sterilisers, the experiments were conducted in accordance to DIN EN 1839-B in a closed autoclave with temperatures and pressures relevant for sterilisation processes. The calculation of flammability limits of process gas mixtures with "SterEx" provides good agreement with flammability limits that were determined in experiments. PMID:19037868

  3. Studies of soil and ecohydrological processes in oil-gas production regions.

    NASA Astrophysics Data System (ADS)

    Khodyreva, E. Ya.; Khodyrev, Yu. P.


    . Soil is an important component of the earth's biosphere because of its crucial role in the hydrological cycle. For revealing possible correlation between spatial distributions of the valuable elements contained both in industrial waters and in tests of soils, 79 samples are prepared and investigated. These tests are selected at superficial geochemical shooting (field monitoring methods of studies) Aznakaevskoi, Karamalinskoi and Sabanchinskoi areas of joint-stock company " Tatneft ". Circuits of distribution of valuable elements on the investigated territory are constructed also a quantitative estimation of the maintenance makro- and microcomponents is given. From the found out elements the greatest interest Na, Mg, K, Ca, Cl, Br and their connections represent because of very high concentration and scandium owing to the cost. Now cost of scandium in the world market approximately in 25 times exceeds cost of gold and is not observed yet tendencies to its decrease. Presence of impurity of salts of heavy metals and their connections in soils, drinking, underground and stratum waters, definition of their concentration and comparison from maximum concentration limit allows to establish the control over dynamics of ecohydrological conditions and in due time to take measures on reduction of negative influence of processes of development of hydrocarbon raw material by an environment.