Nuclear forensic applications of uranium oxide chemistry and morphology

2015 ◽  
Author(s):  
◽  
Alison Louise Tamasi
Keyword(s):  
Uranium Oxide ◽  
Fuel Cycle ◽  
Raw Materials ◽  
Spent Fuel ◽  
Sem Images ◽  
University Of Missouri ◽  
X Ray ◽  
Chemical Signatures ◽  
History Of ◽  
The Stability

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] The entire nuclear fuel cycle is a chemistry-intensive process, from accessing the raw materials from ore, to enriching and forming the fuels, to the eventual long-term disposition or reprocessing of the spent fuel. This chemistry is vital to nuclear forensics, as the chemical history of a sample imbues it with unique signatures that should provide insight into the processing and conversion a sample has undergone. Of course, now that many countries have had nuclear programs for decades, it is appropriate to question the stability of these chemical signatures. This necessitates the assessment of what new chemical and morphological signatures are introduced by the aging in bulk uranium oxide samples, and whether those signatures can be used to elucidate the conditions under which the materials were stored. This thesis is concerned with the analysis of uranium oxide samples: both high-purity UO2, alpha-U3O8, and alpha-UO3 samples, and several legacy U3O8 and UO3 samples. The samples were aged over several years in chambers designed to control temperature and relative humidity. There are two primary focuses for analysis of these aged uranium oxides -- the first is the identification of chemical signatures using powder X-ray diffraction (p-XRD) and extended X-ray absorption fine structure (EXAFS) analysis, and the second is the identification of morphological signatures contained in scanning electron microscopy (SEM) images using a standardized lexicon for consistent textural analysis. LA-UR-15-26762.

scholarly journals Highly Visible Photoluminescence from Ta-Doped Structures of ZnO Films Grown by HFCVD

Crystals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 395 ◽  
Author(s):  
Víctor Herrera ◽  
Tomás Díaz-Becerril ◽  
Eric Reyes-Cervantes ◽  
Godofredo García-Salgado ◽  
Reina Galeazzi ◽  
...  
Keyword(s):  
Raw Materials ◽  
Chemical Vapor ◽  
Growth Direction ◽  
Hexagonal Structure ◽  
Zno Films ◽  
Sem Images ◽  
Wurtzite Phase ◽  
Fixed Amount ◽  
X Ray ◽  
Doped Zno

Tantalum-doped ZnO structures (ZnO:Ta) were synthesized, and some of their characteristics were studied. ZnO material was deposited on silicon substrates by using a hot filament chemical vapor deposition (HFCVD) reactor. The raw materials were a pellet made of a mixture of ZnO and Ta2O5 powders, and molecular hydrogen was used as a reactant gas. The percentage of tantalum varied from 0 to 500 mg by varying the percentages of tantalum oxide in the mixture of the pellet source, by holding a fixed amount of 500 mg of ZnO in all experiments. X-ray diffractograms confirmed the presence of zinc oxide in the wurtzite phase, and metallic zinc with a hexagonal structure, and no other phase was detected. Displacements to lower angles of reflection peaks, compared with those from samples without doping, were interpreted as the inclusion of the Ta atoms in the matrix of the ZnO. This fact was confirmed by energy dispersive X-ray spectrometry (EDS), and X-ray diffraction (XRD) measurements. From scanning electron microscopy (SEM) images from undoped samples, mostly micro-sized semi-spherical structures were seen, while doped samples displayed a trend to grow as nanocrystalline rods. The presence of tantalum during the synthesis affected the growth direction. Green photoluminescence was observed by the naked eye when Ta-doped samples were illuminated by ultraviolet radiation and confirmed by photoluminescence (PL) spectra. The PL intensity on the Ta-doped ZnO increased from those undoped samples up to eight times.

Influence of Gypsum Additive on the Formation of Tobermorite in Autoclaved Aerated Concrete

2016 ◽  
Vol 714 ◽  
pp. 116-121 ◽  
Author(s):  
Ester Helanova ◽  
Rostislav Drochytka ◽  
Vit Cerný
Keyword(s):  
Chemical Composition ◽  
Hydrothermal Reaction ◽  
Raw Materials ◽  
Fly Ashes ◽  
Sem Images ◽  
X Ray ◽  
Autoclaved Aerated Concrete ◽  
Variable Chemical ◽  
Aerated Concrete

The quality of the aerated concrete strongly depends on the chemical composition of the raw materials, as well as the process of the hydrothermal reaction during autoclaving. Due to the variable chemical composition of fly ashes, it is necessary to identify the effect of each ion on the formation of the microstructure of aerated concrete. This paper examines the process of formation of tobermorite with the addition of sulphates in various percentage representation. The microstructure of aerated concrete is assessed using SEM images and the mineralogical by means of X-ray analysis.

scholarly journals Progress in Perovskite Solar Cells towards Commercialization—A Review

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6569
Author(s):  
Hongqiao Wang ◽  
Yunfan Wang ◽  
Zhipeng Xuan ◽  
Tingting Chen ◽  
Jingquan Zhang ◽  
...  
Keyword(s):  
Solar Cells ◽  
Raw Materials ◽  
Rapid Development ◽  
Perovskite Solar Cells ◽  
Pilot Scale ◽  
Production Lines ◽  
Environmental Friendliness ◽  
History Of ◽  
Manufacturing Techniques ◽  
The Stability

In recent years, perovskite solar cells (PSCs) have experienced rapid development and have presented an excellent commercial prospect as the PSCs are made from raw materials that are readily and cheaply available depending on simple manufacturing techniques. However, the commercial production and utilization of PSCs remain immature, leading to substantial efforts needed to boost the development of scalable fabrication of PSCs, pilot scale tests, and the establishment of industrial production lines. In this way, the PSCs are expected to be successfully popularized from the laboratory to the photovoltaic market. In this review, the history of power conversion efficiency (PCE) for laboratory-scale PSCs is firstly introduced, and then some methods for maintaining high PCE in the upscaling process is displayed. The achievements in the stability and environmental friendliness of PSCs are also summarized because they are also of significance for commercialization. Finally, this review evaluates the commercialization prospects of PSCs from the economic view and provides a short outlook.

Variants of the Perspective Closed Fuel Cycle, Based on REMIX-Technology

2014 ◽  
Author(s):  
Evgeniy Bobrov ◽  
Pavel Teplov ◽  
Pavel Alekseev ◽  
Alexander Chibinyaev ◽  
Anatoliy Dudnikox
Keyword(s):  
Fuel Cycle ◽  
Raw Materials ◽  
Natural Uranium ◽  
Depleted Uranium ◽  
Raw Material ◽  
Fissile Material ◽  
Spent Fuel ◽  
Closed Fuel Cycle ◽  
New Variant ◽  
Enriched Uranium

In the traditional closed fuel cycle, based on REMIX-technology (REgenerated MIXture of U and Pu oxides) the fuel composition is produced on the basis of a uranium and plutonium mixture from spent Light Water Reactor (LWR) fuel and additional natural uranium. In this case, there is some saving in the amount of natural uranium used. The basic features of the WWER-1000 fuel loadings with a new variant REMIX-fuel during multiple recycle in the closed nuclear fuel cycle are described in this paper. Such fuel compositions are produced on a basis of a uranium and plutonium mixture allocated at processing the spent fuel after irradiation in the WWER-1000 core, depleted uranium and fission material such as: 235U as a part of high-enriched uranium from the warheads superfluous for defense. Also here variants are considered of the perspective closed fuel cycle in which fissile feed materials for fuel manufacture is produced in the blankets of fast breeder reactors. The fissile material is 233U or Pu. The raw material is depleted uranium from the stocks of enrichment factories, or thorium. Natural uranium is not used in this case. The minimum feed material required for the REMIX technology in a closed fuel cycle was determined through calculations of different types of fissile and raw materials, with different cycle lengths and fuel-water ratios.

Alumina Residue Characterization to Produce Tubular Ceramic Membranes

2012 ◽  
Vol 727-728 ◽  
pp. 1508-1513 ◽  
Author(s):  
Iliana Oliveira Guimarães ◽  
Hélio Lucena Lira ◽  
Sidinei Kleber da Silva ◽  
Suellen Lisboa Dias ◽  
Rosa do Carmo de Oliveira Lima
Keyword(s):  
Electrostatic Precipitator ◽  
Raw Materials ◽  
Environmental Issues ◽  
Ceramic Membranes ◽  
Chemical Compositions ◽  
X Ray Diffraction ◽  
Sem Images ◽  
Calcination Process ◽  
X Ray ◽  
Two Samples

ndustrial wastes recycling become attractive due to raw materials economy (sustainability) and environmental issues. This research objective was to characterize a residue generated during the alumina calcination process (electrostatic precipitator dust), to be applied on the development of tubular ceramic membranes. In this context, two samples were analyzed, a crude residue (sample A) as supplied by the industry and other calcined residue (sample B). As verified by X-ray fluorescence spectroscopy by dispersive energy (XDE), the samples A and B showed a high content of alumina in chemical compositions, both close to 96%. Gibbsite and α-alumina crystalline phases were identified by X-ray diffraction (XRD) in the samples. At scanning electron microscopy (SEM) images, could be observed agglomerates of particles with asymmetric shapes and a wide particle size distribution like was confirmed by laser diffraction, which showed that the particles diameters remained almost unchanged after calcination at 700°C. Results revealed no significant differences between samples characteristics, indicating that the crude and calcined residues could be used to prepare ceramic membranes.

scholarly journals DRY MIXTURES AND MIXING EQUIPMENT FOR THEIR PRODUCTION

2021 ◽  
Vol 5 (12) ◽  
pp. 145-150
Author(s):  
Y. Fadin ◽  
O. Shemetova
Keyword(s):  
Building Materials ◽  
Raw Materials ◽  
Mixing Process ◽  
Chemical Additives ◽  
High Quality ◽  
Main Indicator ◽  
History Of ◽  
The Creation ◽  
The Stability

Today’s economic situation creates conditions for revising the existing base of materials and raw materials in construction, as well as for transforming and using it in the future. One of the ways to achieve this goal is the creation of new types of building materials, more effective and low in the price category compared to the classic ones. Dry building mixtures belongs to such materials. The high quality of dry building mixes is guaranteed by the stability of their composition and the properties of the ingredients used. Saving time when using high-quality dry building mixes will allow to get an irreproachable end result. A necessary component in the manufacture of dry building mixtures is the mixing process, which includes the preparation of raw materials, dosing and the distribution of chemical additives. The main indicator of the quality of the finished product in the production of dry mixes is its uniformity. Therefore, special attention is paid to the mixing section in the production line. The variety of bulk materials and their properties contributes to the creation of various types of mixers for high-quality mixing of components. The article discusses the history of the emergence of dry building mixes and mixing equipment for production.

scholarly journals Structural and Morphological Evaluation of 25% vol. Ni/Al2O3 Nanocomposite Powders Produced by Mechanical Milling

2015 ◽  
Vol 13 ◽  
pp. 48-53 ◽  
Author(s):  
Cristina Voicu ◽  
Florin Popa ◽  
Petru Pascuta ◽  
Ionel Chicinaş
Keyword(s):  
Milling Time ◽  
X Ray Diffraction ◽  
Composite Powders ◽  
Sem Images ◽  
X Ray ◽  
Morphological Evaluation ◽  
Two Phases ◽  
The Stability ◽  
High Level ◽  
Nanocomposite Powders

The evolution of the Al2O3/Ni (25% vol. Ni) composite powders, during the milling and the stability of the composite phases were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray microanalysis (EDX). SEM images show a high level of homogenization of the Ni and Al2O3 phases for milling times larger than 120 minutes. The X-ray study indicates no reaction between the two phases. The crystallite grain size decreases with the milling time for both phases.

scholarly journals From the Ritter pile to the aluminum ion battery – Peter Paufler’s academic genealogy

2020 ◽  
Vol 235 (11) ◽  
pp. 481-511
Author(s):  
Tilmann Leisegang ◽  
Aleksandr A. Levin ◽  
Andreas Kupsch
Keyword(s):  
Raw Materials ◽  
Energy Transition ◽  
Rare Earth Compounds ◽  
Academic Background ◽  
X Ray ◽  
Aluminum Ion ◽  
The Earth ◽  
History Of ◽  
Academic Genealogy ◽  
The Universe

AbstractThis article highlights Peter Paufler’s academic genealogy on the occasion of his 80th birthday. We describe the academic background since 1776, which covers 11 generations of scientists: Ritter, Ørsted, Han-steen, Keilhau, Kjerulf, Brøgger, Goldschmidt, Schulze, Paufler, Meyer, and Leisegang. The biographies of these scientists are described in spotlight character and references to scientists such as Dehlinger, Ewald, Glocker, Röntgen, Vegard, Weiss, and Werner are given. A path is drawn that begins in the Romanticism with electrochemistry and the invention of what is probably the first accumulator. It leads through the industrialization and the modern geology, mineralogy, and crystallography to crystal chemistry, metal and crystal physics and eventually returns to electrochemistry and the aluminum-ion accumulator in the era of the energy transition. The academic genealogy exhibits one path of how crystallography develops and specializes over three centuries and how it contributes to the understanding of the genesis of the Earth and the Universe, the exploration of raw materials, and the development of modern materials and products during the industrialization and for the energy transition today. It is particularly characterized by the fields of physics and magnetism, X-ray analysis, and rare-earth compounds and has strong links to the scientific landscape of Germany (Freiberg) and Scandinavia, especially Norway (Oslo), as well as to Russia (Moscow, Samara, St. Petersburg). The article aims at contributing to the history of science, especially to the development of crystallography, which is the essential part of the structural science proposed by Peter Paufler.

Synthesis of Biogenic Nanosilica from Rice Husk: Using Scaling-Up Batch Reactor from Laboratory

2020 ◽  
Vol 856 ◽  
pp. 198-204
Author(s):  
Ravisara Chainaruprasert ◽  
Thirawudh Pongprayoon
Keyword(s):  
Rice Husk ◽  
Raw Materials ◽  
Batch Reactor ◽  
Sol Gel ◽  
Scaling Up ◽  
Physical Structure ◽  
Nanoparticle Size ◽  
Sem Images ◽  
X Ray ◽  
Imagej Software

Biogenatic nanosilica was synthesized by sol-gel method from rice husk ash. The batch reactor was designed to scaling-up from laboratory scale approximately 5 g to approximately 300 g of the feed raw materials. The synthesized silica products from lab-scale vessel and scaling up designed batch reactor were compared with percent yield and nanoparticle size. The particles of nanosilica from both scale productions were characterized by X-ray Fluorescence (XRF), X-ray Diffraction (XRD) and Scanning Electron Microscope (SEM). The size and size distribution of nanoparticles were estimated by ImageJ software in 100 points from SEM images. The synthesized nanosilica particles from laboratory vessel and designed reactor were the same of % yield production, components, physical structure, silica purity, and nanoparticle size. Moreover, the commercial nanosilica was analyzed for comparison.

Effect of NH4Cl Flux on Structural and Luminescent Properties of CaS: Eu2+ Phosphors

2014 ◽  
Vol 989-994 ◽  
pp. 755-758
Author(s):  
Yun Jie Zhang ◽  
Jie Zhao ◽  
Da Jian Wang ◽  
Jian Ma
Keyword(s):  
Crystal Structure ◽  
Grain Size ◽  
Raw Materials ◽  
Luminescent Properties ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Sem Images ◽  
X Ray ◽  
Structure Morphology ◽  
Scanning Electron

CaS:Eu2+phosphors were prepared by two steps method at a relatively low temperature (1050°C) using NH4Cl as a flux. The influences of NH4Cl flux concentrations on the crystal structure, morphology and photoluminescent properties of CaS:Eu2+phosphors were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), photoluminescence (PL), respectively. XRD analysis shows that when the raw materials added with the NH4Cl flux, the crystal structure was not changed .The SEM images indicate that increase of the NH4Cl flux enlarged the grain size of the phosphor particles. The luminescence intensity of CaS:Eu2+was enhanced with adding NH4Cl flux and up to the maximum emission intensity when the addition of NH4Cl flux is 1wt%.

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