Search results for " mixtures"
showing 10 items of 885 documents
Response of soil phosphatase activities to contamination with two types of tar oil.
2018
Tar oil is a complex mixture of hydrocarbon compounds obtained from high-temperature distillation of coal tar. It has been used for over 100 years from now to protect wood and has been applied to wood products, primary utility poles, and railroad ties by pressure methods. Composition of the tar oil depends on the source and typically consists of 85% polycyclic aromatic hydrocarbons (PAHs), 10% phenolic compounds, and 5% heterocyclic compounds. In this research, we performed the laboratory experiment to compare two types of tar oil: C and GX-Plus, and their effects on P-cycling enzymes (phosphatases) in sandy loam and loamy sand. Tar oil was applied to soil samples at the following doses: 2,…
Toxicity of Dimethoate to Some Soil Animal Species in Different Soil Types
1996
Toxicity of dimethoate (insecticide) to an earthworm (Aporrectodea caliginosa tuberculata), a collembola (Folsomia candida), and an enchytraeid worm (Enchytraeus crypticus/variatus) was studied in three different soil types (artificial soil, clayey soil, and humus sandy soil). Parameters measured were survival and biomass change of the earthworms and survival and reproduction of the collembolas and enchytraeids. The degradation of dimethoate was analyzed too. Toxic effects were observed at the concentrations of some mg/kg dry soil. The biomass reduction of the earthworms occurred at lower concentrations than reduction in survival. The collembolas were more susceptible to dimethoate than the…
Sorption and diffusion properties of volatile phenols into cork
2010
International audience; The sorption and diffusion properties of seven common volatile phenols in hydro-alcoholic medium placed in contact with natural cork were investigated to determine the influence of cork closures on the concentration of these compounds in wine. Weighted cork samples were immersed in model wine solutions containing selected concentrations of each compound and were sampled over time. Sorption coefficients ranged between 125 and 306 mg of aroma compound per kg of cork, while diffusion coefficients varied from 0.8 to 4.1 × 10−11 m2/s. Sorption isotherms of guaiacol and 4-propylguaiacol, respectively, the lowest and highest sorbed compounds of an homologous series of guaia…
Ionic Liquids Binary Mixtures: Promising Reaction Media for Carbohydrates Conversion in 5-HMF
Anthropogenic soils: general aspects and features
2015
In recent decades man's role in soil formation has become a matter of great concern among soil scientists. Man is now considered a soil-forming factor and anthrosolization is recognised as a soil-forming process that consists of a collection of geomorphic and pedological processes resulting from human activities. These human activities include deep working, intensive fertilization, the addition of extraneous materials, irrigation with sediment-rich waters and wet cultivation. In this paper we review the influence of man as a soil forming factor stressing also some peculiar aspects linked to their classification.
Rapid continous radiochemical separations by thermochromatography in connection with a gas-jet recoil-transport system
1980
Abstract A combination of a gas-jet recoil-transport system with a thermochromatographic system has been studied as a technique for rapid, continuous radiochemical separations. Fission products were used as a model for complex mixtures of elements. A nitrogen gas-jet containing potassium chloride clusters was applied to transport nuclides produced in a reactor from the target area to the thermochromatographic column. Conversion of the reaction products carried by the gas-jet volatile species was achieved by stopping the clusters in a quartz-wool plug located in the column and kept at high temperatures and feeding a reactive gas into the column. Several reactive gases producing volatile chlo…
Melittin Modulates Keratinocyte Function through P2 Receptor-dependent ADAM Activation
2012
Melittin, the major component of the bee venom, is an amphipathic, cationic peptide with a wide spectrum of biological properties that is being considered as an anti-inflammatory and anti-cancer agent. It modulates multiple cellular functions but the underlying mechanisms are not clearly understood. Here, we report that melittin activates disintegrin-like metalloproteases (ADAMs) and that downstream events likely contribute to the biological effects evoked by the peptide. Melittin stimulated the proteolysis of ADAM10 and ADAM17 substrates in human neutrophil granulocytes, endothelial cells and murine fibroblasts. In human HaCaT keratinocytes, melittin induced shedding of the adhesion molecu…
High-Temperature Electrolysis of Kraft Lignin for Selective Vanillin Formation
2020
Lignin represents the largest renewable resource of aromatic moieties on earth and harbors a huge potential as a sustainable feedstock for the synthesis of biobased aromatic fine chemicals. Due to the complex, heterogeneous, and robust chemical structure of the biopolymer, the valorization is associated with significant challenges. Unfortunately, technical lignins, which are a large side stream of the pulp and paper industries, are mainly thermally exploited. In this study, technical Kraft lignin was selectively electrochemically depolymerized to the aroma chemical vanillin. Using electricity, toxic and/or expensive oxidizers could be replaced. The electrodegradation of Kraft lignin was per…
Chemometric investigation on structural changes in pine kraft lignin during pulping
2000
Abstract Various structural changes which take place in dissolved lignin during the laboratory-scale kraft pulping of Scots pine (Pinus sylvestris) were studied. Lignin samples were subjected to the alkaline cupric oxide oxidation and the analytical data further processed by various multivariate chemometric techniques (principal component analysis, PCA; principal component regression, PCR; and projection to latent structures, PLS). Several models applicable to the indirect measurement of common pine kraft pulp properties (i.e., total cooking yield, kappa number and ISO brightness) were produced.
Image Quality Assessment Measure Based on Natural Image Statistics in the Tetrolet Domain
2012
This paper deals with a reduced reference (RR) image quality measure based on natural image statistics modeling. For this purpose, Tetrolet transform is used since it provides a convenient way to capture local geometric structures. This transform is applied to both reference and distorted images. Then, Gaussian Scale Mixture (GSM) is proposed to model subbands in order to take account statistical dependencies between tetrolet coefficients. In order to quantify the visual degradation, a measure based on Kullback Leibler Divergence (KLD) is provided. The proposed measure was tested on the Cornell VCL A-57 dataset and compared with other measures according to FR-TV1 VQEG framework.