scholarly journals Grain size and phase purity characterization of U3Si2 fuel pellets

2018 ◽  
Vol 512 ◽  
pp. 199-213 ◽  
Author(s):  
Rita E. Hoggan ◽  
Kevin R. Tolman ◽  
Fabiola Cappia ◽  
Adrian R. Wagner ◽  
Jason M. Harp
Keyword(s):  
Grain Size ◽  
Phase Purity ◽  
Fuel Pellets

Synthesis and Luminescent Property of Nanocrystalline Phosphors via Solvothermal Processes

2006 ◽  
Vol 988 ◽  
Author(s):  
Chien-Yuen Tung ◽  
Shyue-Ming Chang ◽  
Teng-Ming Chen
Keyword(s):  
Grain Size ◽  
Optical Properties ◽  
Luminescent Property ◽  
Commercial Product ◽  
X Ray Diffraction ◽  
Phase Purity ◽  
Emulsion Method ◽  
X Ray ◽  
The Poor

AbstractWe have synthesized a series of nanocrysatlline (5±3 nm in diameter) and submicrom ZnS:Ag,Al phosphors with various dopant compositions via a newly developed emulsion method. The X-ray diffraction (XRD), EDS, SEM, and TEM were utilized in the characterization of phase purity and microstructure of phosphor particles. Photoluminescence (PL) and cathodoluminescence (CL) spectra were also utilized to characterize the optical properties of blue-emitting phosphor. The CL intensity of submicron ZnS:Ag,Al phosphor was found to be weaker than that of corresponding commercial product, which was attributed to the poor crystallinity and small grain size. In this article we described the synthesis of ZnS:Ag,Al nanophosphor with emphasis on the correlation between spectroscopic features and the microstructure.

scholarly journals Grain Size and Phase Purity Characterization of U3Si2 Pellet Fuel

2018 ◽  
Author(s):  
Rita E. Hoggan ◽  
Kevin R. Tolman ◽  
Fabiola Cappia ◽  
Adrian R. Wagner ◽  
Jason M. Harp
Keyword(s):  
Grain Size ◽  
Phase Purity

Structural and Electrical Characterization of Shaped Beam Laser Recrystallized Polysilicon on Amorphous Substrates

1981 ◽  
Vol 4 ◽  
Author(s):  
T. J. Stultz ◽  
J. F. Gibbons
Keyword(s):  
Grain Size ◽  
Electrical Characterization ◽  
Grain Structure ◽  
Electrical Characteristics ◽  
Shaped Beam ◽  
Beam Laser ◽  
Cw Laser ◽  
Amorphous Substrates ◽  
Circular Beam

ABSTRACTStructural and electrical characterization of laser recrystallized LPCVD silicon films on amorphous substrates using a shaped cw laser beam have been performed. In comparing the results to data obtained using a circular beam, it was found that a significant increase in grain size can be achieved and that the surface morphology of the shaped beam recrystallized material was much smoother. It was also found that whereas circular beam recrystallized material has a random grain structure, shaped beam material is highly oriented with a <100> texture. Finally the electrical characteristics of the recrystallized film were very good when measured in directions parallel to the grain boundaries.

Effect of grain size on recrystallization in high burnup fuel pellets

1997 ◽  
Vol 248 ◽  
pp. 196-203 ◽  
Author(s):  
K. Nogita ◽  
K. Une ◽  
M. Hirai ◽  
K. Ito ◽  
K. Ito ◽  
...  
Keyword(s):  
Grain Size ◽  
Fuel Pellets ◽  
High Burnup

Grain Subdivision Fission Gas Swelling Model for UO2

MRS Advances ◽  
2016 ◽  
Vol 1 (35) ◽  
pp. 2465-2470
Author(s):  
Thomas Winter ◽  
Richard Hoffman ◽  
Chaitanya S. Deo
Keyword(s):  
Grain Size ◽  
Grain Boundaries ◽  
Gas Diffusion ◽  
Fine Grain ◽  
Fuel Pellets ◽  
Model And Simulation ◽  
Nucleation Sites ◽  
Fission Gas ◽  
High Burnup ◽  
Swelling Model

ABSTRACTUnder high burnup UO2 fuel pellets can experience high burnup structure (HBS) at the rim also known as rim effect. The HBS is exceptionally porous with fine grain sizes. HBS increases the swelling further than it would have achieved at a larger grain size. A theoretical swelling model is used in conjunction with a grain subdivision simulation to calculate the swelling of UO2. In UO2 the nucleation sites are at vacancies and the bubbles are concentrated at grain boundaries. Vacancies are created due to irradiation and gas diffusion is dependent on vacancy migration. In addition to intragranular bubbles, there are intergranular bubbles at the grain boundaries. Over time as intragranular bubbles and gas atoms accumulate on the grain boundaries, the intergranular bubbles grow and cover the grain faces. Eventually they grow into voids and interconnect along the grain boundaries, which can lead to fission gas release when the interconnection reaches the surface. This is known as the saturation point. While the swelling model used does not originally incorporate a changing grain size, the simulation allows for more accurate swelling calculations by introducing a fractional HBS based on the temperature and burnup of the pellet. The fractional HBS is introduced with a varying grain size. Our simulations determine the level of swelling and saturation as a function of burnup by combining an independent model and simulation to obtain a more comprehensive model.

scholarly journals Application of Electron Backscatter Diffraction (EBSD) for Crystallographic Characterization of Aluminum-Doped Zinc Oxide Sputtered Films

2013 ◽  
Vol 19 (S4) ◽  
pp. 103-104
Author(s):  
C.B. Garcia ◽  
E. Ariza ◽  
C.J. Tavares
Keyword(s):  
Electron Microscopy ◽  
Grain Size ◽  
Zinc Oxide ◽  
Electron Backscatter Diffraction ◽  
Wide Range ◽  
Electron Backscatter ◽  
Aluminum Doped Zinc Oxide ◽  
Ebsd Technique ◽  
Backscatter Diffraction

Zinc Oxide is a wide band-gap compound semiconductor that has been used in optoelectronic and photovoltaic applications due to its good electrical and optical properties. Aluminium has been an efficient n-type dopant for ZnO to produce low resistivity films and high transparency to visible light. In addition, the improvement of these properties also depends on the morphology, crystalline structure and deposition parameters. In this work, ZnO:Al films were produced by d.c. pulsed magnetron sputtering deposition from a ZnO ceramic target (2.0 wt% Al2O3) on glass substrates, at a temperature of 250 ºC.The crystallographic orientation of aluminum doped zinc oxide (ZnO:Al) thin films has been studied by Electron Backscatter Diffraction (EBSD) technique. EBSD coupled with Scanning Electron Microscopy (SEM) is a powerful tool for the microstructural and crystallographic characterization of a wide range of materials.The investigation by EBSD technique of such films presents some challenges since this analysis requires a flat and smooth surface. This is a necessary condition to avoid any shadow effects during the experiments performed with high tilting conditions (70º). This is also essential to ensure a good control of the three dimensional projection of the crystalline axes on the geometrical references related to the sample.Crystalline texture is described by the inverse pole figure (IPF) maps (Figure 1). Through EBSD analysis it was observed that the external surface of the film presents a strong texture on the basal plane orientation (grains highlighted in red colour). Furthermore it was possible to verify that the grain size strongly depends on the deposition time (Figure 1 (a) and (b)). The electrical and optical film properties improve with increasing of the grain size, which can be mainly, attributed to the decrease in scattering grain boundaries which leads to an increasing in carrier mobility (Figure 2).The authors kindly acknowledge the financial support from the Portuguese Foundation for Science and Technology (FCT) scientific program for the National Network of Electron Microscopy (RNME) EDE/1511/RME/2005.

scholarly journals Characterization of sand boils with grading entropy

2012 ◽  
pp. 73-88
Author(s):  
Laslo Nadj
Keyword(s):  
Grain Size ◽  
Distribution Curve ◽  
Practical Consideration ◽  
Implicit Information ◽  
Sand Boil ◽  
Sand Boils ◽  
Grain Distribution ◽  
Soil Behaviour ◽  
The Relationship

Grain size and grain distribution by size are dominant factors determining soil behaviour. The shape and position of a grain distribution curve contain implicit information about the propensity of sand boiling or piping at flood conditions. The author used 1040-grain distribution curves taken from 12 sand boil locations to study the relationship between sand boils, hydraulic soil failures and entropy. The results have justified the hypotheses and indicated some fairly important details for practical consideration. Calculating grain distribution entropy is not ?magic? with mathematics: it simply helps put the expected behaviour of soils into a different perspective and promotes orientation for classifying soils according to a new parameter related to grain movement.

scholarly journals The Enhancement and Study of Sintering Time Effect Toward Content of Fe and Ti Compounds in Mineral Sand

2020 ◽  
Vol 9 (2) ◽  
pp. 55-58
Author(s):  
Fauzi Fauzi ◽  
Zulfalina Zulfalina
Keyword(s):  
Grain Size ◽  
Magnetic Separation ◽  
Raw Materials ◽  
Weight Fraction ◽  
Time Effect ◽  
Sintering Time ◽  
Magnetite Fe3o4 ◽  
Hematite Fe2o3 ◽  
Black Color

Pasir mineral merupakan salah satu mineral endapan (sedimen) dengan ukuran butir 0,074-5 mm, ukuran kasar (5–3 mm) dan halus (1 mm), ciri fisik dari pasir mineral ini diantaranya berwarna hitam dan cenderung tertarik oleh magnet. Berdasarkan beberapa penelitian yang telah dilakukan sebelumnya didapatkan bahwa kandungan utama dari pasir mineral berupa mineral ilmenit (FeTiO3), hematite (Fe2 - O3), dan magnetit (Fe3O4). Oleh karena itu maka pasir mineral ini sangat potensial untuk menghasilkan logam Fe, Ti, besi oksida dan pigmen titanium oksida. Dalam penelitian ini pengayaan kandungan besi dilakukan dengan metode separasi magnetik kemudian dikarakterisasi menggunakan XRF. Selanjutnya sampel tersebut disinter pada suhu 800oC, dengan variasi waktu penahanan selama 2, 4 dan 6 jam dan di karakterisasi menggunakan XRD, dimana hasilnya dianalisis dengan metode GSAS. Hasil pengujian XRF menunjukkan bahwa pasir mineral murni (bahan mentah) mempunyai kandungan Fe dan Ti masing–masing 14,38 dan 2,80% (%berat), sedangkan setelah separasi magnetik kandungan Fe dan Ti meningkat masing–masing menjadi 83,51 dan 7,25% (%berat). Hasil analisis GSAS menunjukkan bahwa waktu sintering berpengaruh terhadap fraksi berat Fe dan Ti, ini ditunjukkan senyawa Fe3O4 menurun dari 81,85 menjadi 77,76% dan Fe2O3 dari 11,44 menjadi 3,41%, sementara FeTiO3 meningkat dengan bertambahnya waktu sintering dari 6,72 menjadi 18,83%. The mineral sand is one of the mineral sediments with grain size of 0.074 – 5 mm, coarse size (5–3 mm) and fine (1 mm). The physical characteristics of this mineral sand are black color and tend to be attracted by magnets. Based on several studies, the main content of mineral sand is ilmenite (FeTiO3), hematite (Fe2O3), and magnetite (Fe3O4). Therefore mineral sand is very potential to produce Fe, Ti, iron oxide and titanium oxide pigments. In this study, the iron contents from raw materials were enhanced by magnetic separation method, and then the samples were characterized using XRF. Therefore they were sintered at temperature 800oC and variation of holding times 2, 4 and 6 h. The characterization of sample used XRD, where this result is analyzed using GSAS method. The XRF results showed that pure mineral sand (raw materials), has Fe and Ti contents of 14.38 and 2.80% (%weight), whereas after magnetic separation, the Fe and Ti contents increased to 83.51 and 7.25%, respectively. The analysis result of GSAS showed that the sintering time affected the weight fraction of Fe and Ti. These indicated that Fe3O4 decreased from 81.85 to 77.76% and Fe2O3 from 11.44 to 3.41%, while FeTiO3 raise with increasing of sintering time from 6.72 to 18.83%. Keywords: Enhancement, sintering time, compound content, mineral sand, GSAS

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