An empirical model of sediment deposition processes in Lake Kerkini, Central Macedonia Greece

2009 ◽  
Vol 164 (1-4) ◽  
pp. 573-592 ◽  
Author(s):  
Aris Psilovikos ◽  
Sofia Margoni
Keyword(s):  
Empirical Model ◽  
Sediment Deposition ◽  
Deposition Processes ◽  
Lake Kerkini

scholarly journals Analysis of silting and hydrodynamic processes in the degrading floodplain-valley reservoir (on the example of the Krasnodar Reservoir)

2020 ◽  
Vol 26 (2) ◽  
pp. 335-348
Author(s):  
Andrey Laguta ◽  
Anatoly Pogorelov
Keyword(s):  
River Flow ◽  
Water Area ◽  
Sediment Deposition ◽  
Water Masses ◽  
Northern Coast ◽  
Average Speed ◽  
Transformation Mechanisms ◽  
Deposition Processes ◽  
Kuban River ◽  
The Right

Based on the data of bathymetric surveys, topographic maps, and satellite images, the article analyzes sediment deposition processes in the bowl of the floodplain-valley Krasnodar Reservoir in connection with the circulation of water masses. Over the period of operation since 1973, the area of the Krasnodar reservoir decreased by 35 % with a significant decrease in usable volume. Particular attention is paid to the analysis of water circulation — the most important factor in the formation of the siltation body, processing of coasts and distribution of sediments. The average annual siltation of the Krasnodar Reservoir for 2005–2016 estimated at 6.9 mn m3. The greatest increase in the thickness of the siltation body (4–8 m or more) was recorded in the estuarine areas of the largest rivers flowing into the reservoir — within the estuary of the Kuban river and the Belaya river delta. In general, the formation of deltas plays a key role in the transformation of the reservoir. The upcoming Kuban delta from 1977–2018 occupied an area of 41.41 km2 in the water area of the reservoir, and the extension deltas formed by the Belaya river currently have a total area of 25.22 km2. The circulation of water masses was studied using an acoustic Doppler profilograph. Bowl transformation mechanisms and sediment deposition features are considered in the aspect of the movement of water masses in connection with the river flow and wind components of the circulation, as well as hydrodynamics at the mouth of the Kuban. It has been established that in the transverse profile in the reservoir there are two multidirectional flows. The main one is the right flow, formed under the influence of the Kuban runoff and the discharge of water from the reservoir, with a direction to the south-west (along the northern coast) and an average speed of 0.04 m/s; the left flow at an average speed of 0.01 m/s is directed east. Flow rates decrease with approach to the circulation axis.

Chemical and Electrochemical Heteroepitaxial Growth of Chalcogenide Semiconductors from Solutions

1996 ◽  
Vol 451 ◽  
Author(s):  
D. Lincot ◽  
M. J. Furlong ◽  
M. Froment ◽  
R. Cortes ◽  
M. C. Bernard
Keyword(s):  
Heteroepitaxial Growth ◽  
X Ray Diffraction ◽  
Basic Principles ◽  
Lattice Match ◽  
X Ray ◽  
Chalcogenide Semiconductors ◽  
Influence Of Temperature On ◽  
Deposition Processes ◽  
A Site ◽  
Site Selective

ABSTRACTChalcogenide semiconductors have been deposited epitaxially from aqueous solutions either chemically or electrochemically at growth rates of up to 0.7 μmhr−1. After recalling the basic principles of these deposition processes, results are presented concerning chemically deposited CdS on InP, GaP and CuInSe2 substrates, electrodeposited CdTe on InP, and CdSAnP heterostructures. Characterisation of these structures by RHEED, TEM, HRTEM, and glazing angle X ray diffraction allows to analyse the effects of substrate orientation, polarity, lattice match plus the influence of temperature on epitaxial growth. These results are discussed in terms of self organisation and a site selective growth mechanisms due to the free enegy of formation of each compound.

Synthesis of dispersed mesoporous powders solid solution Zr0.88Ce0.12O2 for catalyst carrier of the conversion of methane to synthesis –gas

2020 ◽  
pp. 73-83
Author(s):  
L. V. Morozova ◽  
◽  
I. A. Drozdova ◽  
Keyword(s):  
Solid Solution ◽  
Total Pore Volume ◽  
Nitrogen Adsorption ◽  
Primary Crystal ◽  
X Ray ◽  
Catalyst Carrier ◽  
Conversion Of Methane ◽  
Deposition Processes ◽  
Zirconia Oxide ◽  
Coprecipitation Of Hydroxides

The xerogels in the system 0.88 mol.% ZrO2 − 0.12 mol.% CeO2 were obtained by the method of coprecipitation in a neutral (pH = 7) and slightly alkaline (pH = 9) medium under the influence of ultrasound with the size of the agglomerates 70 – 230 nm. It is shown that the coprecipitation of hydroxides of zirconium and cerium at pH = 9 with the use of ultrasonic treatment facilitates the formation of a primary crystal is symbolic of the particles in the xerogel, whose size is ~ 5 nm, whereas the xerogel synthesized in a neutral environment consists only of the x-ray amorphous phase. The effect of pH-precipitation on deposition processes of dehydration of the xerogels and crystallization solid solution based on zirconia oxide in the metastable pseudocubic modification (с′-ZrO2) was discovered. It was found that in the temperature range 500 – 800 °C there is a phase transition с′-ZrO2 → t-ZrO2, the size of the crystallites of the formed tetragonal solid solutions is 8 and 11 nm. The method of low-temperature nitrogen adsorption were investigated dispersion properties and characteristics of the pore structure of the powders of the solid solution Zr0.88Ce0.12O2. It is determined that the specific surface area of t-ZrO2 samples obtained after firing at 800 °C is 117 and 178 m2/g, the total pore volume reaches 0.300 − 0.325 cm3/g, the pore size distribution is monomodal and is in the range of 2 − 8 nm. The effect of thermal “aging” at a temperature of 800 °C (40 h) on the structure and dispersion of the solid solution t-ZrO2 powders was studied.

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