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New Methodologies for the Characterization and Separation of Rare Earth Elements Present in CoalKiser, Michael James 24 November 2015 (has links)
Three phases of work were performed for this study. First a new form of liberation analysis was created and applied to two coal samples from separate formations. This new method of liberation analysis attempts to remove sources of error found in the traditional form of liberation analysis. This new method is capable of producing results comparable to multiple iterations of the traditional liberation analysis while using only one head sample. The new method relies on the mathematical reconstruction of the data to produce the resulting liberation profile. This allows the user to easily expand the method to include more liberation profiles without greatly increasing the amount of head weight needed. The results of this phase confirm that the products of each liberation profile reconstitute the correct feed ash.
The second phase of work focused on the evaluation and concentration of rare earth elements (REEs) present in the refuse streams of coal processing plants found in the eastern United States. Twenty plants were sampled for the fleet study. Samples of these plants' refuse streams were collected and their REE and ash contents were determined. Coal from the Eagle seam, Fire Clay seam, and Fire Clay Rider were collected and tested during the concentration phase. Samples of a waste coal from the Pittsburgh seam and a coal combustion by prodcut were also provided by a third party. The separation methods investigated include multi-gravity separation, electrostatic separation, and selective oil agglomeration. Partition curves from x-ray sorting devices were also applied to REE float-sink data as well. The results of this work show that REEs tend to partition with low ash material when viewing the results on an ash basis.
Finally, the third phase of this work involved the application of x-ray sorting technology on different coals. This work showed that the x-ray sorting technology in question is capable of effectively treating prescreened feed with a size range of 2" x 1/4". The work also shows that the x-ray sorting technology also has applications in the power generation field, where it can be used to eliminate elements of environmental concern. / Ph. D.
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Some Thermodynamic Properties of Rare Earth Thiofluoride and Caβ"-Alumina CompoundsKoch, Mark 04 1900 (has links)
Abstract Specifics included in thesis. / Thesis / Master of Engineering (MEngr)
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Polynuclear Rare-earth (RE) based Metal-Organic Frameworks (MOFs): From Topological Exploration to Preparation of Tailor-made MOFsAssen, Ayalew H. 09 1900 (has links)
Metal-organic frameworks (MOFs) have emerged as a unique class of solid-state materials, exemplifying the power of combining organic and inorganic chemistries to address the enduring challenge pertaining to designing solid state materials with desired attributes. Notably, a myriad of MOFs were constructed in the last two decades. In particular, the use of well-defined polyatomic clusters as molecular building blocks (MBBs) permitted access to the looked-for geometrical features, incorporated in preselected building units prior to the assembly process, guiding the assembly of a targeted network. Nevertheless, the diverse coordination modes and geometries of rareearth (RE) elements requires the introduction of a sophisticated controlled approach for their use as polynuclear cluster MBBs. Subsequently, our group has introduced the use of 2-fluorobenzoic acid (2-FBA) modulator that consistently allows the in situ control and formation of multi-nuclear RE MBBs. The presented work in this thesis demonstrates the use of elaborate RE MBBs and their successful deployment in reticular chemistry for the construction of particular MOF platforms expressing unique properties in term of gas separations. Accordingly, the RE hexanuclear clusters were used to construct fcu- and fluMOF platforms with controlled pore-aperture sizes. Markedly, the isolated RE-MOFs, REfum-fcu-MOF and RE-bqdc-flu-MOF, showed unprecedented paraffin/isoparaffin molecular sieving.
Further tuning of the windows of RE-fcu-MOFs afforded the assembly of a MOF suitable for propylene/propane separation. The exceptional thermal and chemical stability and high adsorption selectivity of some of these MOFs prompted us to explore the fcu-MOF platform for selective removal of H2S/CO2 from CH4 and for sensing of toxic gases, namely H2S and NH3.
Additionally, the research presented in this dissertation highlights the topological exploration for the formation of new MOFs: i) highly-connected polyatomic RE-MOFs in combination with tetrahedrally oriented tetracarboxylate ligands afforded the formation MOFs with new underlying topologies, namely kna-, kel- and kem-MOFs; ii) mixed-metal approach (RE plus other elements) was employed to fabricate MOFs containing in situ formed metalo-linker MBBs that are difficult to be pre-assembled by organic synthesis; iii) supermolecular building layer (SBL) approach was extended from the prevalent sql to the less explored double sql layer for the rational design of pillared MOFs.
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Observation of Gapless Nodal-Lines in a Rare-Earth-Based CompoundSmith, Robert 01 January 2023 (has links) (PDF)
This thesis aims to contribute to the understanding of quantum materials by employing a combination of experimental techniques, such as angle-resolved photoemission spectroscopy and magnetic and transport measurements. Further collaborative support in the form of first-principles calculations is included and discussed in tandem. In this thesis, a lanthanide-based semimetal of the ZrSiS type, is investigated. Multiple nodal lines which remain gapless are observed along the X-R direction of the Brillouin zone. We also present a nodal line that is observed further below the Fermi level and aligned in the G-M direction; this nodal line appears to be sensitive to light source polarization. A surface state at the X point is also observed. Finally, this thesis includes some discussion on the development of a sample growth laboratory, along with the presentation and characterization of grown Bi2Se3 samples. With potential applications in the fields of spintronics and novel microelectronic devices, the experimental realization and understanding of quantum materials is key to a deeper understanding of materials physics.
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Growth and Mechanisms for Rare-Earth-Doped GaN Electroluminescent Devices (ELDs)Lee, Dong-Seon 14 March 2002 (has links)
No description available.
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Theoretical & Experimental Investigation of Low and Negative Electron Affinity Cold Cathodes Based on Rare-Earth MonosulfidesModukuru, Yamini 02 September 2003 (has links)
No description available.
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INVESTIGATION OF THE USE OF RARE-EARTH SULFIDE THIN FILMS AS EFFICIENT CATHODES IN ORGANIC LIGHT EMITTING DIODESGARRE, KALYAN January 2004 (has links)
No description available.
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Molecular Beam Epitaxy (MBE) Growth of Rare Earth Doped Gallium Nitride for Laser Diode ApplicationPark, Jeongho 21 July 2006 (has links)
No description available.
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Experimental and Theoretical Investigation of Absorption and Emission Cross-Sections in Rare Earth Doped GaN EpilayersVemuru, Ajay Sandeep 03 October 2008 (has links)
No description available.
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Spectroscopic Studies of Ytterbium Doped III-Nitride SemiconductorsWang, Jingzhou 21 September 2009 (has links)
No description available.
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