Transportation pathways of pesticides in two major watersheds of Istanbul, Turkey

2004 ◽  
Vol 49 (3) ◽  
pp. 165-172 ◽  
Author(s):  
M. Yazgan ◽  
A. Tanik
Keyword(s):  
Chemical Properties ◽  
Surface Flow ◽  
Priority List ◽  
Pesticide Pollution ◽  
Consumption Values ◽  
Annual Consumption ◽  
Agricultural Areas ◽  
Physical And Chemical ◽  
And Chemical Properties

The study covers the investigation of pesticides in terms of consumption, toxicological classification and various intrinsic physical and chemical properties like DT50, KOC, GUS, solubility that describe the important mechanisms prevailing in soil, namely persistence and mobility. These mechanisms help to estimate the transportation pathways of pesticides on soil till they reach the receiving water after being applied on land. Classification is done in three groups, those likely to appear in surface flow, those that appear in groundwater and those that present transient conditions. Such an approach that also takes into account toxicological levels and annual consumption values of pesticides will act as a tool to prepare the priority list of pesticides that need special care during their transportation. The fate of pesticides is a difficult task to solve, however, such a methodology, puts forth a rough estimate on their behavior in spite of uncertainties in many of the parameters describing mechanisms like persistence and mobility. The agricultural areas of two watersheds of Istanbul are selected as target areas to describe the approach, which is also checked with another approach estimating pesticide pollution potential that considers various other properties of pesticides. Almost similar findings are depicted with 85% proximity. The methodology presented in the paper illustrates and emphasizes the significant role of pesticide properties in determining their fate in soil after being applied.

Basic Performance Research of Polymer Intercalation Clay

2012 ◽  
Vol 578 ◽  
pp. 183-186
Author(s):  
Xiao Chun Cao ◽  
Yi Qin ◽  
Yan Na Zhao ◽  
Kun Ke
Keyword(s):  
Drilling Fluid ◽  
Chemical Properties ◽  
Drilling Fluids ◽  
Technical Problems ◽  
Clay Particles ◽  
Polymer Properties ◽  
Physical And Chemical ◽  
Performance Research ◽  
And Chemical Properties

Using the preliminary research of the polymer properties, the different between the physical and chemical properties of new polymer-clays nanometer composites and clay have been studied. Different polymers are used to evaluate experiment. Based on a large number of lab experiments, the changes of rheological property and API filtration property of polymer-clay drilling fluids nanometer composites are studied. The results show that clay particles could become smaller and the composites drilling fluid have the role of controlling loss and enhancing cake quality. The prepared composites could be used to solve the technical problems in drilling fluid.

Role of lattice defects in catalytic activities of graphene clusters for fuel cells

2015 ◽  
Vol 17 (26) ◽  
pp. 16733-16743 ◽  
Author(s):  
Lipeng Zhang ◽  
Quan Xu ◽  
Jianbing Niu ◽  
Zhenhai Xia
Keyword(s):  
Fuel Cells ◽  
Electronic Structures ◽  
Chemical Properties ◽  
Lattice Defects ◽  
Physical And Chemical Properties ◽  
Catalytic Activities ◽  
Physical And Chemical ◽  
And Chemical Properties

Defects are common but important in graphene, which could significantly tailor the electronic structures and physical and chemical properties.

scholarly journals Partial synthetic models of FeMoco with sulfide and carbyne ligands: Effect of interstitial atom in nitrogenase active site

2021 ◽  
Vol 118 (49) ◽  
pp. e2109241118
Author(s):  
Linh N. V. Le ◽  
Gwendolyn A. Bailey ◽  
Anna G. Scott ◽  
Theodor Agapie
Keyword(s):  
Active Sites ◽  
Chemical Properties ◽  
Metal Centers ◽  
Bridging Ligand ◽  
Reduction Potentials ◽  
Protein Active Sites ◽  
Physical And Chemical ◽  
Synthetic Models ◽  
And Chemical Properties

Nitrogen-fixing organisms perform dinitrogen reduction to ammonia at an Fe-M (M = Mo, Fe, or V) cofactor (FeMco) of nitrogenase. FeMco displays eight metal centers bridged by sulfides and a carbide having the MFe7S8C cluster composition. The role of the carbide ligand, a unique motif in protein active sites, remains poorly understood. Toward addressing how the carbon bridge affects the physical and chemical properties of the cluster, we isolated synthetic models of subsite MFe3S3C displaying sulfides and a chelating carbyne ligand. We developed synthetic protocols for structurally related clusters, [Tp*M’Fe3S3X]n−, where M’ = Mo or W, the bridging ligand X = CR, N, NR, S, and Tp* = Tris(3,5-dimethyl-1-pyrazolyl)hydroborate, to study the effects of the identity of the heterometal and the bridging X group on structure and electrochemistry. While the nature of M’ results in minor changes, the chelating, μ3-bridging carbyne has a large impact on reduction potentials, being up to 1 V more reducing compared to nonchelating N and S analogs.

scholarly journals THE ROLE OF EARTHWORMS IN PASTURE PRODUCTION AND MOISTURE CONSERVATION

1966 ◽  
pp. 168-183 ◽  
Author(s):  
S.M.J. Stockdill ◽  
G.G. Cossens
Keyword(s):  
Soil Erosion ◽  
Chemical Properties ◽  
Infiltration Rate ◽  
Physical And Chemical Properties ◽  
Soil Infiltration ◽  
Pasture Production ◽  
Physical And Chemical ◽  
Soil Infiltration Rate ◽  
And Chemical Properties

RESEARCH has shown that pasture production on soils without earthworms is limited to considerably less than the true potential. Increased production with beneficial earthworms is associated with pronounced changes in the physical and chemical properties of the soil. Infiltration rate is increased, moisture is conserved and the risk of soil erosion is reduced

scholarly journals Effects of pig slurry application on soil physical and chemical properties and glyphosate mobility

2014 ◽  
Vol 38 (5) ◽  
pp. 1421-1431 ◽  
Author(s):  
Daniela Aparecida de Oliveira ◽  
Adilson Pinheiro ◽  
Milton da Veiga
Keyword(s):  
Agricultural Soils ◽  
Chemical Properties ◽  
Pig Slurry ◽  
Physical And Chemical Properties ◽  
Surface Layers ◽  
Extractable P ◽  
Crop Cycle ◽  
Agricultural Areas ◽  
Physical And Chemical ◽  
And Chemical Properties

Pig slurry applied to soil at different rates may affect soil properties and the mobility of chemical compounds within the soil. The purpose of this study was to evaluate the effects of rates of pig slurry application in agricultural areas on soil physical and chemical properties and on the mobility of glyphosate through the soil profile. The study was carried out in the 12th year of an experiment with pig slurry applied at rates of 0 (control), 50, 100 and 200 m³ ha-1 yr-1 on a Latossolo Vermelho distrófico (Hapludox) soil. In the control, the quantities of P and K removed by harvested grains were replaced in the next crop cycle. Soil physical properties (bulk density, porosity, texture, and saturated hydraulic conductivity) and chemical properties (organic matter, pH, extractable P, and exchangeable K) were measured. Soil solution samples were collected at depths of 20, 40 and 80 cm using suction lysimeters, and glyphosate concentrations were measured over a 60-day period after slurry application. Soil physical and chemical properties were little affected by the pig slurry applications, but soil pH was reduced and P levels increased in the surface layers. In turn, K levels were increased in sub-surface layers. Glyphosate concentrations tended to decrease over time but were not affected by pig slurry application. The concentrations of glyphosate found in different depths show that the pratice of this application in agricultural soils has the potential for contamination of groundwater, especially when the water table is the surface and heavy rains occur immediately after application.

scholarly journals Cyclodextrins: Structural, Chemical, and Physical Properties, and Applications

2021 ◽  
Vol 3 (1) ◽  
pp. 1-31
Author(s):  
Benjamin Gabriel Poulson ◽  
Qana A. Alsulami ◽  
Abeer Sharfalddin ◽  
Emam. F. El Agammy ◽  
Fouzi Mouffouk ◽  
...  
Keyword(s):  
Organic Compounds ◽  
Chemical Properties ◽  
Aqueous Solubility ◽  
Industrial Applications ◽  
Physical And Chemical Properties ◽  
To Come ◽  
Novel Applications ◽  
Physical And Chemical ◽  
And Chemical Properties

Due to their unique structural, physical and chemical properties, cyclodextrins and their derivatives have been of great interest to scientists and researchers in both academia and industry for over a century. Many of the industrial applications of cyclodextrins have arisen from their ability to encapsulate, either partially or fully, other molecules, especially organic compounds. Cyclodextrins are non-toxic oligopolymers of glucose that help to increase the solubility of organic compounds with poor aqueous solubility, can mask odors from foul-smelling compounds, and have been widely studied in the area of drug delivery. In this review, we explore the structural and chemical properties of cyclodextrins that give rise to this encapsulation (i.e., the formation of inclusion complexes) ability. This review is unique from others written on this subject because it provides powerful insights into factors that affect cyclodextrin encapsulation. It also examines these insights in great detail. Later, we provide an overview of some industrial applications of cyclodextrins, while emphasizing the role of encapsulation in these applications. We strongly believe that cyclodextrins will continue to garner interest from scientists for many years to come, and that novel applications of cyclodextrins have yet to be discovered.

Sign in / Sign up

Export Citation Format

Share Document