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Na podstawie równania Laplace'a wyprowadzono zależność między siłą działającą pomiędzy dwoma ziarnami materiału glebowego przez fazę wodną, a składowymi swobodnej energii powierzchniowej. Stwierdzono zależność wartości sił oddziaływań od zawartości Corg w badanych glebach. Dla gleb o zawartości Corg powyżej 40% wartości tych sił są ujemne. Słowa kluczowe: siły adhezji, kąt zwilżania, składowe swobodnej energii powierzchniowej.
In the present work problems related to surface free energy of different agricultural materials such as clay minerals, mineral soils, organic soils and forest litter were considered. Methodical investigations of surface free energy determination as well as fundamental investigations connected with the influence of the surface cations and organic substance on the wettability, free energy and interaction forces between clay minerals and soil particles were undertaken. The interaction forces between clay minerals and soil particles perform a fundamental role in aggregation, flocculation and forming of solids structure. In case of solids the surface free energy can be determined indirectly for example from the measured contact angles or from the adsorption values (by determination of film pressure jt) with appropriate theoretical assumptions. Such methods were applied in this paper to determine surface free energy components for clay minerals and soils. Because of difficulties in contact angle measurements by sessile drop method (especially for organic soils and humus) thin layer wicking or thin column wicking technique were applied. The investigations of penetration rates of water and organic liquids carried out for clay minerals and their mono ionic forms showed the close dependence between the kind of mineral and surface cation. The linear dependence of penetration rates was obtained at the lowest penetration times for bentonite and the highest for kaolin. The kind and properties (e.g. radius of hydrated ions) play in this case an important role. The empiric series of wettability, depending on clay mineral and surface cation were determined experimentally. Similar measurements were performed for clay minerals with increasing additions of humic acid and for different soils. On the basis of the measurements the surface free energy components apolar and polar (electron-acceptor and electron-donor) were calculated and correlated with the kind of clay mineral, surface cation and humic acid content. The investigations for soils show that the penetration times depend on the soil samples. Contact angle values for investigated samples were also calculated. From the water vapour adsorption measurements on the surfaces of modified clay minerals and soils the water film pressure values were calculated for one or three monolayers and compared with the work of adhesion and immersion. For soil materials surface free energy had real influence on structure formation or its changes. The organic matter and surface cations had an important role in creation of soil structure.
Pore size distribution functions obtained from mercury intrusion porosimetry, water potential (pF), and water vapor desorption measurements were calculated and compared for few soil samples differing in granulometric composition, surface area and organic matter content. The pore size distributions calculated for the given sample from various measuring methods differ markedly among others. The highest differences were observed for Othic Podzol, less for Orthic Rendzina and the least for Orthic Luvisol. The variations in pore size characteristics, except of character of soil material, seem to be caused by the assumptions used in pore calculations from particular experimental data and by various ranges of the pores which may be detected by a given method, as well. The full characteristics of the porous system of a porous material may be obtained by comparison of the results obtained using a few methods simultaneously. The use of only one method should not be recommended.
Surface free energy and contact angle for peat-moorsh soils were determined on soil samples consisted of two kinds of moorsh formations, i.e., peaty moorsh (Z1) and proper moorsh (Z3). The samples represented peat soil mass in different state of its secondary transformation, so they essentially differed in values of W1 index. In study a thin-layer (TLW) technique based on Wash- burns equation was used. For this purpose the penetration rate of n-alkanes and diodomethane were measured. If the content of humous compounds in the soil exceeds 40%, wetting rate measurements can only be performed using apolar liquids, such as diiodomethane and alkanes. Polar liquids, on the other hand, such as water or formamide, do not penetrate porous soil layers. This shows that the tested material displays only dispersion-type surface interactions. Therefore, for "mor" and peat soils, the technique of thin-layer wicking with n-octane could only be used to determine the dispersive component . The investigated peat soil no exhibit a polar interactions because the water does not penetrate into yiLW the sample. For the peaty-moorsh soils only dispersive surface free energy components can be determined by the technique of thin-column wicking (TCW). Contact angles can be calculated from the determined dispersive surface free energy components and water surface tension by Young equation. Ranges of water contact angles for peat-moorsh soils are 97.5°<9 <102.0°.
Two nonionic flocculants, Magnafloc 351 and Rokrysol WF-1, have been applied in different doses to two pseudopodzolic soils: sandy and loessial. The filtration rate, evaporation and aggregate stability have been measured. The amount of the leached flocculants has been used as an estimation of their bonding force to the soil phase. The investigated soil properties have been improved under the influence of both flocculants, in different degree depending on the kind of soil. Physical properties of PAM-modified soils are quite similar.
W pracy tej została zanalizowany wpływ materiałów budowlanych na zmiany właściwości fizykochemiczne gleb miejskich. Wykonano analizy pH, kwasowości hydrolitycznej, zawartości kationów. Zmierzono też powierzchnię właściwą analizowanych próbek wykorzystując dwie metody: adsorpcję pary wodnej i adsorpcję azotu. Do analiz użyto następujące materiały budowlane: cegłę, beton, gazobeton, piasek oraz ich mieszaniny z glebą. Jako glebę wzorcową użyto glebę lessową charakterystyczną dla terenu miasta Lublina. Analizowana gleba została pobrana z odkrywki - Elizówka k. Lublina Słowa kluczowe: urbanoziemy. materiały budowlane, właściwości fizykochemiczne, adsorpcja azotu, adsorpcja pary wodnej.
Influence of microrelief and liming on the soil reaction and the microstructure of acid sandy forest soil were investigated. Sampling site was a 40 year old pine plantation on a Cambic Arenosol. The site was characterized by ridge - furrow microrelief. The microstructure of soil samples, taken from two profiles was determined on the base of the mercury intrusion porosimetry measurements. Total porosite, pore volume, bulk density and pore size distribution curves were obtained. Generally, a decrease of the microstuctura) parameters after liming were observed, especially in the ridge samples. Dependence between organic carbon, fulvic to humic acids ratio and total porosity, pore volume, bulk density for lime sample was noted. Solubilization of organic matter, their redistribution within soil profile by leaching and their quantity and quality are the base for explaining the influence of liming on the microstructure of forest soil.
Badano opór penetracji w glebie gli­niastej i piaszczystej modyfikowanejsorbentem poliamido­wym, w warunkach różnej wilgotności. Za pomocą porozymetrii rtęciowej określano zmianę mikrostruktury gleb pod wpływem sorbenta poliamidowego. Stwierdzono wpływ wielkości dawki sorbenta zarówno na wielkość oporu penetracji, jak i na rozkład wielkości porów bada­nych gleb. Wpływ ten był bardziej korzystny dla gleby ciężkiej.
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