A structure relaxation model based on the empirical electron theory of solids and molecules is developed to compute the diffusion active energies of C, N in γFe. First, adding a restriction, the lattice maintains rig...A structure relaxation model based on the empirical electron theory of solids and molecules is developed to compute the diffusion active energies of C, N in γFe. First, adding a restriction, the lattice maintains rigidity when solute atom migrates to the saddle point. In this step, the hybridization classes of every atom do not change. Then, the restriction is loosed and the atoms are relaxed under the coulomb repulsive forces. It is supposed that the energy needed in the first step would be compensated partly by the second step. In this way, the diffusion active energies of C, N in γFe are computed. Compared with the experiment data, the relative errors are less than 5%, which are good results in the computation of activation energy of diffusion.展开更多
The FAs （fulvic acids） belong to natural organic contaminants that are commonly found in different environments. In the process of oxidation and disinfection FAs are precursors of toxic substances, which cause a pro...The FAs （fulvic acids） belong to natural organic contaminants that are commonly found in different environments. In the process of oxidation and disinfection FAs are precursors of toxic substances, which cause a problem in many water treatment plants. In the sewage treatment plants, FAs are not biodegradable and together with purified wastewater and are discharged into surface waters. One of important source of the formation of FAs is the municipal landfill. In this thesis the authors test the amount of soluble fulvic acids present in the leachate of Barycz landfill in Krakow. The extracted FAs were subjected to a detailed analysis for the content of metals and IR spectrum analysis has also been done. Basing on elemental composition the C/O, C/H and C/N ratios have been determined. The obtained data were compared with the characteristics specified in the literature.展开更多
The goal of this work was to assess soil microbial respiration, determined by the assay of community-level physiological profiling in an oxygen-sensitive microplate （O2-CLPP）, in response to endogenous C and several...The goal of this work was to assess soil microbial respiration, determined by the assay of community-level physiological profiling in an oxygen-sensitive microplate （O2-CLPP）, in response to endogenous C and several individual C substrates in the soils with different organic C contents （as a function of soil type and management practice）. We also used the O2-CLPP to determine the respiratory response of these soils to endogenous C and amended C substrates with N addition. A respiratory quotient （RQ） was calculated based on the ratio of the response to endogenous soil C vs. each C-only substrate, and was related to total organic carbon （TOC）. For assessing N availability for microbial activity, the effect of N supplementation on soil respiration, expressed as Nr^tio, was calculated based on the response of several substrates to N addition relative to the response without N. Soils clustered in 4 groups after a principal component analysis （PCA）, based on TOC and their respiratory responses to substrates and endogenous C. These groups reflected differences among soils in their geographic origin, land use and C content. Calculated RQ values were significantly lower in natural forest soils than in managed soils for most C-only substrates. TOC was negatively correlated with RQ （r = -0.65）, indicating that the soils with higher organic matter content increased respiratory efficiency. The N addition in the assay in the absence of C amendment （i. e., only endogenous soil C present） had no effect on microbial respiration in any soil, indicating that these soils were not intrinsically N-limited, but substrate-dependent variation in Nr^tio within soil groups was observed.展开更多
文摘A structure relaxation model based on the empirical electron theory of solids and molecules is developed to compute the diffusion active energies of C, N in γFe. First, adding a restriction, the lattice maintains rigidity when solute atom migrates to the saddle point. In this step, the hybridization classes of every atom do not change. Then, the restriction is loosed and the atoms are relaxed under the coulomb repulsive forces. It is supposed that the energy needed in the first step would be compensated partly by the second step. In this way, the diffusion active energies of C, N in γFe are computed. Compared with the experiment data, the relative errors are less than 5%, which are good results in the computation of activation energy of diffusion.
文摘The FAs （fulvic acids） belong to natural organic contaminants that are commonly found in different environments. In the process of oxidation and disinfection FAs are precursors of toxic substances, which cause a problem in many water treatment plants. In the sewage treatment plants, FAs are not biodegradable and together with purified wastewater and are discharged into surface waters. One of important source of the formation of FAs is the municipal landfill. In this thesis the authors test the amount of soluble fulvic acids present in the leachate of Barycz landfill in Krakow. The extracted FAs were subjected to a detailed analysis for the content of metals and IR spectrum analysis has also been done. Basing on elemental composition the C/O, C/H and C/N ratios have been determined. The obtained data were compared with the characteristics specified in the literature.
文摘The goal of this work was to assess soil microbial respiration, determined by the assay of community-level physiological profiling in an oxygen-sensitive microplate （O2-CLPP）, in response to endogenous C and several individual C substrates in the soils with different organic C contents （as a function of soil type and management practice）. We also used the O2-CLPP to determine the respiratory response of these soils to endogenous C and amended C substrates with N addition. A respiratory quotient （RQ） was calculated based on the ratio of the response to endogenous soil C vs. each C-only substrate, and was related to total organic carbon （TOC）. For assessing N availability for microbial activity, the effect of N supplementation on soil respiration, expressed as Nr^tio, was calculated based on the response of several substrates to N addition relative to the response without N. Soils clustered in 4 groups after a principal component analysis （PCA）, based on TOC and their respiratory responses to substrates and endogenous C. These groups reflected differences among soils in their geographic origin, land use and C content. Calculated RQ values were significantly lower in natural forest soils than in managed soils for most C-only substrates. TOC was negatively correlated with RQ （r = -0.65）, indicating that the soils with higher organic matter content increased respiratory efficiency. The N addition in the assay in the absence of C amendment （i. e., only endogenous soil C present） had no effect on microbial respiration in any soil, indicating that these soils were not intrinsically N-limited, but substrate-dependent variation in Nr^tio within soil groups was observed.
