Kinetics of Reduction and Precipitation of U(VI) in the Dissolution of UO2(s) Under Anoxic Conditions in NaCl 5 mol kg−1. Influence of Metallic Iron

1997 ◽  
Vol 506 ◽  
Author(s):  
J. Giménez ◽  
M. Molera ◽  
I. Casas ◽  
M.E. Torrero ◽  
J. de Pablo
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Order Kinetic ◽  
Spent Fuel ◽  
Experimental Conditions ◽  
First Order ◽  
Lower Solubility ◽  
Kinetics Of ◽  
Kinetics Of Reduction ◽  
Scanning Electron

ABSTRACTExperiments of spent fuel dissolution performed in presence of iron show, for uranium as well as for some radionuclides, lower final concentrations than measured in similar experiments but in absence of iron. So far, only the final concentrations obtained in these experiments have been published. In this work, we have focused our study on the reduction of uranium (VI) due to the presence of iron and the subsequent precipitation of Uranium (IV) due to its lower solubility. This behavior has been confirmed using a Scanning Electron Microscope by observing an uranium phase precipitated on the iron surface and assuming, under the experimental conditions, that it most likely corresponds to U02(s). We have modeled this process assuming a first-order kinetic.

The Photoluminescence Spectra Research of SiC Thin Film under Different Sputtering Powers

2019 ◽  
Vol 295 ◽  
pp. 93-97
Author(s):  
Chang Zhao ◽  
Man Zhao ◽  
Su Ye Lv ◽  
Qing Jun Liu ◽  
Guang Jian Xing
Keyword(s):  
Thin Film ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Crystal Morphology ◽  
Growth Conditions ◽  
Photoluminescence Spectra ◽  
Experimental Conditions ◽  
Grain Sizes ◽  
Power Inputs ◽  
Scanning Electron

This study prepared an SiC thin film by using the ratio frequency magnetron sputtering method, investigated the effects of different sputtering powers on the SiC material and analysed the changes in crystal morphology and photoluminescence characteristics caused by changes in the growth conditions used. It was considered that there was 6H-SiC crystal morphologies in the SiC thin film under the experimental conditions prevailing in this study. The SiC morphologies with small grain sizes intermingled and therefore formed anSiC thin film. The analyses of the photoluminescence spectra and Scanning Electron Microscope indicated that the SiC thin film materials with preferable crystal compositions could be prepared under appropriate power inputs.

The Effect of Surface Finish on Zinc Whisker Growth

2012 ◽  
Vol 472-475 ◽  
pp. 2756-2759
Author(s):  
Wen Cui ◽  
Shao Jun Qi
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Surface Finish ◽  
Whisker Growth ◽  
Experimental Conditions ◽  
Steel Substrates ◽  
The Relationship ◽  
Rough Surface Finish ◽  
Scanning Electron ◽  
Effect Of Surface

To understand the relationship between surface finish and zinc whisker growth, this study investigated the growth of whiskers on two mild steel substrates of different surface finish by Field Emission Gun Scanning Electron Microscope (FEG SEM). Results show that, under the same experimental conditions, deposits on substrates with a mirror finish grew less whiskers and nodules than substrates with a rough surface finish.

A Mechanical Evaluation of Implants Placed With Different Surgical Techniques Into the Trabecular Bone of Goats

2007 ◽  
Vol 33 (2) ◽  
pp. 51-58 ◽  
Author(s):  
Manal M. Shalabi ◽  
Johannes G. C. Wolke ◽  
Anja J. E. de Ruijter ◽  
John A. Jansen
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Statistical Significance ◽  
Surgical Techniques ◽  
Preparation Technique ◽  
Machined Surface ◽  
Implant Surface ◽  
Experimental Conditions ◽  
Removal Torque ◽  
Scanning Electron

Abstract The aim of the study was to assess the effects of surgical technique and implant surface roughness on implant fixation. A total of 48 screw implants with machined or etched surface topographies were placed into the femoral condyles of goats. The implant sites were prepared by a conventional technique, by undersized preparation, or by the osteotome technique. Bone tissue responses were evaluated after 12 weeks of healing by removal torque testing and histologic analysis using scanning electron microscope. The cumulative removal torque value of the etched implants placed with the undersized technique (98 ± 29 Ncm) was higher (50 ± 35 Ncm) to a level of statistical significance than machined surface implants placed by the osteotome technique. Scanning electron microscope evaluation indicated that all implants showed interfacial bone contact. The torque test resulted in fracture at the bone-implant interface for all experimental conditions. Installation of etched implants using an undersized preparation of the implant bed resulted in superior bonding strength with the surrounding bone at 12 weeks after surgery. Evidently, the undersized preparation technique improved the early fixation of oral implants in this study.

scholarly journals Degradation of Tannic Acid Using TiO2 Nanotubes as Electrocatalyst

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
N. Lakshmi Kruthika ◽  
G. Bhaskar Raju ◽  
S. Prabhakar
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Uv Radiation ◽  
Tannic Acid ◽  
Tio2 Nanotubes ◽  
Zero Order ◽  
Titanium Sheet ◽  
Kinetics Of ◽  
Scanning Electron ◽  
Tannic Acid Solution

Structured TiO2 nanotubes were grown on 2 mm thick titanium sheet by anodization of titanium in ethylene glycol medium containing 0.025 M NaF. The morphology of TiO2 nanotubes (TNT) was characterized using field emission scanning electron microscope. The potential of TNT as anode and also as photocatalyst for the degradation of tannic acid was studied. The mineralization of tannic acid was measured in terms Total Organic Carbon (TOC). Only 50% of TOC could be removed by exposing the tannic acid solution to UV-radiation (photolysis), whereas it was improved to 70% by electrooxidation (EO) using TNT as anode. Maximum degradation of 83% was achieved when electrooxidation was conducted under the influence of UV-radiation (photoelectrocatalytic process (PEC)). Among the electrolytes tried, Na2SO4 was observed to be very effective for the degradation of tannic acid. The kinetics of tannic acid degradation by photoelectrocatalytic process was found to follow zero-order rate expression.

Closed-Cell Foam Skin Thickness Measurement Using a Scanning Electron Microscope

2011 ◽  
Vol 17 (5) ◽  
pp. 772-778 ◽  
Author(s):  
Clifford S. Todd ◽  
Valentina Kuznetsova
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Thickness Measurement ◽  
Skin Thickness ◽  
Polymer Foam ◽  
Experimental Conditions ◽  
Skin Cell ◽  
Beam Sample ◽  
Closed Cell ◽  
Scanning Electron

AbstractClosed cell polymer foam skin thickness can be assessed by taking backscatter electron (BSE) images in a scanning electron microscope (SEM) at a series of accelerating voltages. Under a given set of experimental conditions, the electron beam mostly passes through thin polymer skin cell walls. That cell appears dark compared to adjacent thicker-skinned cells. Higher accelerating voltages lead to a thicker skin being penetrated. Monte Carlo modeling of beam-sample interactions indicates that at 5 keV, skin less than ∼0.5 μm in thickness will appear dark, whereas imaging at 30 keV allows skin thicknesses up to ∼4 μm to be identified. The distribution of skin thickness can be assessed over square millimeters of foam surface in this manner. Qualitative comparisons of the skin thicknesses of samples can be made with a simple visual inspection of the images. A semiquantitative comparison is possible by applying image analysis. The proposed method is applied to two example foams. Characterizing foam skin thickness by this method is possible using any SEM that is capable of collecting useful BSE images over a range of accelerating voltages. Imaging in low vacuum, where an electrically conductive metal coating is not required, leads to more sensitivity in skin thickness characterization.

scholarly journals Permeation Characterization of the Sequence of Intersecting Ink and Seal Lines Using Field Emission Scanning Electron Microscope

CONVERTER ◽  
2021 ◽  
pp. 176-189
Author(s):  
Jiangchun Li, Et al.
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Field Emission ◽  
Criminal Cases ◽  
Experimental Conditions ◽  
Cross Sectional ◽  
Daily Work ◽  
Judicial Appraisal ◽  
Scanning Electron

Objectives: Paper documents are playing an increasingly important role in people's daily work with the development of economy, society and culture. In the practice of judicial appraisal, the sequence of the intersections of ink and seal on suspicious documents can often provide critical information for the detection of criminal cases. The examination of sequence of intersecting seal and ink lines is to judge the sequence of seal and ink mark formation by certain technical means.Methods: A representative black signature pen, ink, and specific paper are selected to prepare experimental samples. Under the given experimental conditions, the field emission scanning electron microscope is used to perform micro-morphology on the cross-sectional characteristics of the samples and all the characterization results obtained are systematically analyzed to summarize the specificity of the sample. Results: The results showed that the proposed method can efficiently discriminate the Permeation Characterization of the sequence of intersecting seal and ink lines.Conclusions: This research is expected to be applied to forensic investigation for counterfeiting documents and bring new developments in the field of document inspection.

The Alteration of the Pore Spaces in Sandstones

1973 ◽  
Vol 31 ◽  
pp. 210-211
Author(s):  
R. E. Ferrell ◽  
G. G. Paulson
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
The Other ◽  
Coarse Grained ◽  
Depositional Fabric ◽  
Soluble Components ◽  
Scanning Electron ◽  
Shape And Size

The pore spaces in sandstones are the result of the original depositional fabric and the degree of post-depositional alteration that the rock has experienced. The largest pore volumes are present in coarse-grained, well-sorted materials with high sphericity. The chief mechanisms which alter the shape and size of the pores are precipitation of cementing agents and the dissolution of soluble components. Each process may operate alone or in combination with the other, or there may be several generations of cementation and solution.The scanning electron microscope has ‘been used in this study to reveal the morphology of the pore spaces in a variety of moderate porosity, orthoquartzites.

The Broad Applications of the Scanning Electron Microscope

1969 ◽  
Vol 27 ◽  
pp. 20-21
Author(s):  
C. T. Nightingale ◽  
S. E. Summers ◽  
T. P. Turnbull
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Light Microscopy ◽  
Surface Topography ◽  
Great Depth ◽  
Resolving Power ◽  
Depth Of Field ◽  
Pictorial Representations ◽  
Scanning Electron

The ease of operation of the scanning electron microscope has insured its wide application in medicine and industry. The micrographs are pictorial representations of surface topography obtained directly from the specimen. The need to replicate is eliminated. The great depth of field and the high resolving power provide far more information than light microscopy.

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