Effect of Ce4+ and Th4+ Ion Substitution in Uranium Dioxide

2012 ◽  
Vol 1383 ◽  
Author(s):  
Rakesh K. Behera ◽  
Chaitanya S. Deo
Keyword(s):  
Uranium Dioxide ◽  
Ionic Radius ◽  
Chemical Properties ◽  
Fission Products ◽  
Lattice Parameter ◽  
Ion Concentration ◽  
Vegard’S Law ◽  
Ion Substitution ◽  
Physical And Chemical ◽  
Thermo Physical Properties

ABSTRACTUranium dioxide is the most common fuel used in commercial light water nuclear reactors. The fission of the fuel generates fission products (FPs) and minor actinides (MAs), which affects the thermo-physical properties of the fuel. The understanding of the physical and chemical properties of the FPs and MAs is still limited. In this study we have used atomic level simulations to estimate the effect of Ce4+ and Th4+ ions in urania matrix. Our results show that the structural variation depends on the elastic effect, which is guided by the ionic radius of the substituted ion. Ce4+ (ionic radius 0.97 Å) reduces the overall lattice parameter, while Th4+ (ionic radius 1.05 Å) increases the overall lattice parameter of the urania matrix (U4+ ionic radius 1.00 Å). In addition bulk modulus of the U1-xCexO2 system does not change with substitution while the modulus of U1-xThxO2 reduces with an increase in Th4+ ion concentration. This observation is in accordance with Vegard’s law prediction based on the modulus values of bulk UO2, CeO2 and ThO2 systems.

scholarly journals A Study of Zooplankton Community in Dukan Lake, Kurdistan Region-Iraq, with a New Record of Craspedacusta sowerbii Lankester (1880) Medusa (Cnidaria: Hydrozoa)

2017 ◽  
Vol 14 (4) ◽  
pp. 735-741 ◽  
Author(s):  
Baghdad Science Journal
Keyword(s):  
Similarity Index ◽  
Chemical Properties ◽  
Zooplankton Community ◽  
Ion Concentration ◽  
Hydrogen Ion Concentration ◽  
Alkaline Side ◽  
Physical And Chemical ◽  
First Time ◽  
Jaccard's Similarity Index ◽  
And Chemical Properties

A study of Zooplankton community has been carried out at four selected sites on Dukan Lake. Samples of water and zooplankton were collected monthly for the period from July 2015 to February 2016. Some physical and chemical properties of water were studied and the results showed that the air temperature were ranged from 0 to 36.16 °C, water temperature ranged from 2.83 to 34.66 °C, hydrogen ion concentration of studied sites were found to lie in alkaline side, it was ranged between 6.87 to 8.57, electrical conductivity ranged from 190.79 to 850.08 µs.cm­¹, turbidity ranged from 0.9-7.7 NTU, and dissolved oxygen from 3.3 to 6.8 mg.l-¹ while BOD5 were ranged from 0.53 to 34.66 mg.l-¹. Concerning to the zooplankton, 37 species were identified which belonged to Cladocera (48.38%), Copepod (43.28%), Rotifera (8.23%), Targigrada (0.08%) and Cnidaria (0.1%). The medusa of Craspedacusta sowerbii Lankester (1880) was recorded for the first time in Iraq. Regarding to zooplankton community, rotifer were ranged between 0 to 690.91 ind.m-3, Copepoda from 54.55 to 5927.27 ind.m-3 and Cladocera ranged from 18.18 to 6072.73 ind.m-3. According to Shanon-Weiner index, species diversity for zooplankton invertebrates was ranged from 0.325 to 1.091 bits/ind. Jaccard’s similarity index showed that the highest similarity was recorded between site (1) and site (4) with 40.74%.

Methods of Forecasting Wear Resistance of Cutting Tools Based on the Properties of their Materials

2014 ◽  
Vol 682 ◽  
pp. 491-494 ◽  
Author(s):  
Vladislav Bibik ◽  
Elena Petrova
Keyword(s):  
Tool Life ◽  
Metal Cutting ◽  
Cutting Tool ◽  
Cutting Tools ◽  
Chemical Properties ◽  
Tool Material ◽  
Composition Structure ◽  
Metal Cutting Tool ◽  
Physical And Chemical ◽  
Thermo Physical Properties

The author considers methods of forecasting metal-cutting tool life based on characteristics of cutting tool material. These characteristics depend on differences in numerical values of physical and chemical properties of tool material due to changes in its composition, structure, and production process variables. The described methods allow obtaining the information necessary for forecasting the tool life beyond the process of cutting, for example at the stage of cutting tool manufacturing. The author suggests using the method of registration of thermo-physical properties of the tool material as a promising forecasting technique.

Removal of Mn(II) from Aqueous Solution Using Saponified Garlic Peel

2014 ◽  
Vol 694 ◽  
pp. 382-386 ◽  
Author(s):  
Bo Liang ◽  
Wan He Zhao ◽  
Kai Huang ◽  
Hong Min Zhu
Keyword(s):  
Metal Ion ◽  
Chemical Properties ◽  
Correlation Coefficients ◽  
Ion Concentration ◽  
Batch Adsorption ◽  
Maximum Adsorption Capacity ◽  
Pseudo Second Order ◽  
Ft Ir ◽  
Physical And Chemical ◽  
Garlic Peel

The removal of Mn (II) ion by saponified garlic peel (S-GP) was investigated using batch adsorption. SEM and FT-IR were employed to investigate the physical and chemical properties of S-GP. The adsorption was evaluated as a function of initial metal ion concentration, contact time and temperature. The maximum adsorption capacity for Mn (II) was 0.51 mol/kg, and the adsorption process followed the Langmuir model. Pseudo-second-order models fitted the experimental data well and kinetic parameters, rate constants, equilibrium sorption capacity and related correlation coefficients at various temperatures were calculated and discussed. A possible adsorption mechanism based on a cation exchange was proposed for the adsorption of Mn (II).

scholarly journals Preparation and Physical and Photocatalytic Activity of a New Niobate Oxide Material Containing NbO4 Tetrahedra

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Hengkai Pan ◽  
Bei Wang ◽  
Feng Zhang ◽  
Weifeng Zhang ◽  
Guoqiang Li
Keyword(s):  
Photocatalytic Activity ◽  
Chemical Properties ◽  
Ambient Air ◽  
Oxygen Adsorption ◽  
Lattice Parameter ◽  
Oxide Material ◽  
Scattering Spectra ◽  
New Material ◽  
Raman Scattering Spectra ◽  
Physical And Chemical

The shape and connection type of MOx are critical to the physical and chemical properties. A series of new material Sr2-xNaxNbO4 containing NbO4 tetrahedra was prepared by controlling the ratio of SrCO3 to sodium niobate under ambient air. With increasing the content of Sr in the sample, the MOx shape will change from NbO6 octahedra to NbO4 tetrahedra, which is confirmed by the Raman scattering spectra. With increasing the content of NbO4 in the sample, the lattice parameter increases, optical band gap becomes larger, and the surface changes to be more active for oxygen adsorption, resulting in a higher photocatalytic activity.

Feasibility of immobilizing fluorinated pyrochemical reprocessing salts in a glass-ceramic matrix

2004 ◽  
Vol 848 ◽  
Author(s):  
Agnès Grandjean
Keyword(s):  
Glass Ceramic ◽  
Raw Materials ◽  
Chemical Properties ◽  
Fission Products ◽  
Ceramic Matrix ◽  
Extraction Process ◽  
Spent Fuel ◽  
Molten Fluoride ◽  
Materials Used ◽  
Physical And Chemical

ABSTRACTSpent fuel reprocessing by an innovative reductive extraction process in a molten fluoride medium (LiF/AlF3) is now being evaluated; in this hypothesis, all the unrecoverable fission products would be conditioned as fluorides. A preliminary study was undertaken to assess the feasibility of incorporating these fluorides by melting in a glass-ceramic matrix. The containment matrix for the fluorinated waste stream was selected after examining the consequences of fluorinated compounds on the vitreous state and on the physical and chemical properties of the melt and the solidified glass. The presence of fluorinated compounds in the raw materials used to produce the vitreous material raises the problem of the volatility of some fluorides, of their solubility in the melt, and of possible crystallization of the material.

Statistical criteria of stellar population types

1966 ◽  
Vol 24 ◽  
pp. 101-110
Author(s):  
W. Iwanowska
Keyword(s):  
Stellar Population ◽  
Chemical Properties ◽  
Spectrophotometric Study ◽  
Physical And Chemical Properties ◽  
Population Type ◽  
The Galaxy ◽  
Distribution Parameters ◽  
Physical And Chemical ◽  
Statistical Criteria ◽  
And Chemical Properties

In connection with the spectrophotometric study of population-type characteristics of various kinds of stars, a statistical analysis of kinematical and distribution parameters of the same stars is performed at the Toruń Observatory. This has a twofold purpose: first, to provide a practical guide in selecting stars for observing programmes, second, to contribute to the understanding of relations existing between the physical and chemical properties of stars and their kinematics and distribution in the Galaxy.

Biophysical Measurement of Molecular Weight of Foot-and-Mouth Disease RNA Fragments

1974 ◽  
Vol 32 ◽  
pp. 262-263
Author(s):  
Sydney S. Breese ◽  
Howard L. Bachrach
Keyword(s):  
Chemical Properties ◽  
Foot And Mouth Disease ◽  
Mouth Disease ◽  
Distilled Water ◽  
Bovine Plasma ◽  
Mouth Disease Virus ◽  
Foot And Mouth ◽  
Carbon Coated ◽  
Rna Fragments ◽  
Physical And Chemical

Continuing studies on the physical and chemical properties of foot-and-mouth disease virus (FMDV) have included electron microscopy of RNA strands released when highly purified virus (1) was dialyzed against demlneralized distilled water. The RNA strands were dried on formvar-carbon coated electron microscope screens pretreated with 0.1% bovine plasma albumin in distilled water. At this low salt concentration the RNA strands were extended and were stained with 1% phosphotungstic acid. Random dispersions of strands were recorded on electron micrographs, enlarged to 30,000 or 40,000 X and the lengths measured with a map-measuring wheel. Figure 1 is a typical micrograph and Fig. 2 shows the distributions of strand lengths for the three major types of FMDV (A119 of 6/9/72; C3-Rezende of 1/5/73; and O1-Brugge of 8/24/73.

Tailoring microstructures of materials through biomimetics

1993 ◽  
Vol 51 ◽  
pp. 500-501
Author(s):  
Mehmet Sarikaya ◽  
Ilhan A. Aksay
Keyword(s):  
Chemical Properties ◽  
Design And Synthesis ◽  
Structure Sensitive ◽  
Macro Scale ◽  
Methods Of Synthesis ◽  
Successive Level ◽  
Engineering Materials ◽  
Physical And Chemical ◽  
And Chemical Properties ◽  
Synthesis Of Materials

Biomimetics involves investigation of structure, function, and methods of synthesis of biological composite materials. The goal is to apply this information to the design and synthesis of materials for engineering applications.Properties of engineering materials are structure sensitive through the whole spectrum of dimensions from nanometer to macro scale. The goal in designing and processing of technological materials, therefore, is to control microstructural evolution at each of these dimensions so as to achieve predictable physical and chemical properties. Control at each successive level of dimension, however, is a major challenge as is the retention of integrity between successive levels. Engineering materials are rarely fabricated to achieve more than a few of the desired properties and the synthesis techniques usually involve high temperature or low pressure conditions that are energy inefficient and environmentally damaging.In contrast to human-made materials, organisms synthesize composites whose intricate structures are more controlled at each scale and hierarchical order.

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