Дисертації з теми "Bulk oxides"
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Koethe, Thomas Christoph. "Bulk sensitive photoelectron spectroscopy of strongly correlated transition metal oxides." [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=982912900.
Повний текст джерелаBALDINI, ANGELICA. "SYNTHESIS AND CHARACTERIZATION OF BULK NANOSTRUCTURED OXIDES FOR FUNCTIONAL APPLICATIONS." Doctoral thesis, Università degli studi di Pavia, 2021. http://hdl.handle.net/11571/1429995.
Повний текст джерелаWalker, Robert. "The surface chemistry and bulk electronic structure of bismuth based pyrochlore oxides." Thesis, Imperial College London, 2016. http://hdl.handle.net/10044/1/48468.
Повний текст джерелаGil-Acevedo, Jennifer 3664585. "Sensitivity of Marine Cynobacteria and Green Microlage to Nano and Bulk Zinc Oxides." FIU Digital Commons, 2018. https://digitalcommons.fiu.edu/etd/3845.
Повний текст джерелаBirkner, Nancy R. "Thermodynamics of Manganese Oxides at Bulk and Nanoscale| Phase Formation, Transformation, Oxidation-Reduction, and Hydration." Thesis, University of California, Davis, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=3706557.
Повний текст джерелаNatural manganese oxides are generally formed in surficial environments that are near ambient temperature and water-rich, and may be exposed to wet-dry cycles and a variety of adsorbate species that influence dramatically their level of hydration. Manganese oxide minerals are often poorly crystalline, nanophase, and hydrous. In the near-surface environment they are involved in processes that are important to life, such as water column oxygen cycling, biomineralization, and transport of minerals/nutrients through soils and water. These processes, often involving transformations among manganese oxide polymorphs, are governed by a complex interplay between thermodynamics and kinetics. Manganese oxides are also used in technology as catalysts, and for other applications.
The major goal of this dissertation is to examine the energetics of bulk and nanophase manganese oxide phases as a function of particle size, composition, and surface hydration. Careful synthesis and characterization of manganese oxide phases with different surface areas provided samples for the study of enthalpies of formation by high temperature oxide melt solution calorimetry and of the energetics of water adsorption on their surfaces. These data provide a quantitative picture of phase stability and how it changes at the nanoscale.
The surface energy of the hydrous surface of Mn3O4 is 0.96 ± 0.08 J/m2, of Mn2O3 is 1.29 ± 0.10 J/m2, and of MnO2 is 1.64 ± 0.10 J/m2. The surface energy of the anhydrous surface of Mn3O4 is 1.62 ± 0.08 J/m 2, of Mn2O3 is 1.77 ± 0.10 J/m 2, and of MnO2 is 2.05 ± 0.10 J/m2. Supporting preliminary findings (Navrotsky et al., 2010), the spinel phase (Mn3O4) has a lower surface energy (more stabilizing) than bixbyite, while the latter has a smaller surface energy than pyrolusite. These differences significantly change the positions in oxygen fugacity—temperature space of the redox couples Mn3O4-Mn2O 3 and Mn2O3-MnO2 favoring the lower surface enthalpy phase (the spinel Mn3O4) for smaller particle size and in the presence of surface hydration.
Chemisorption of water onto anhydrous nanophase Mn2O 3 surfaces promotes rapidly reversible redox phase changes at room temperature as confirmed by calorimetry, X-ray diffraction, and titration for manganese average oxidation state. Water adsorption microcalorimetry (in situ) at room temperature measured the strongly exothermic integral enthalpy of water adsorption (-103.5 kJ/mol) and monitored the energetics of the redox phase transformation. Hydration-driven redox transformation of anhydrous nanophase Mn(III) 2O3, (high surface enthalpy of anhydrous surfaces 1.77 ± 0.10 J/m2) to Mn(II,III)3O4 (lower surface enthalpy 0.96 ± 0.08 J/m2) occurred during the first few doses of water vapor. Surface reduction of nanoparticle bixbyite (Mn 2O3) to hausmannite (Mn3O4) occurs under conditions where no such reactions are seen or expected on grounds of bulk thermodynamics in coarse-grained materials.
Layered structure manganese oxides contain alkali or alkaline earth cations and water, are generally fine-grained, and have considerable thermodynamic stability. The surface enthalpies (SE) of layered and tunnel structure complex manganese oxides are significantly lower than those of the binary manganese oxide phases. The SE for hydrous surfaces and overall manganese average oxidation state (AOS) (value in parentheses) are: cryptomelane 0.77 ± 0.10 J/m 2 (3.78), sodium birnessite 0.69 ± 0.13 J/m2 (3.56), potassium birnessite 0.55 ± 0.11 J/m2 (3.52), and calcium birnessite 0.41 ± 0.11 J/m2 (3.50). Surface enthalpies of hydrous surfaces of the calcium manganese oxide nanosheets are: δCa 0.39MnO2.3nH2O 0.75 ± 0.10 J/m2 (3.89) and δCa0.43MnO2.3nH2O 0.57 ± 0.12 J/m2 (3.68). The surface enthalpy of the complex manganese oxides appears to decrease with decreasing manganese average oxidation state, that is, with greater mixed valence manganese (Mn 3+/4+). Low surface energy suggests loose binding of H2O on the internal and external surfaces and may be critical to catalysis in both natural and technological settings.
Budde, Melanie. "Heteroepitaxy, surface- and bulk hole transport, and application of the p-type semiconducting oxides NiO and SnO." Doctoral thesis, Humboldt-Universität zu Berlin, 2020. http://dx.doi.org/10.18452/22240.
Повний текст джерелаThis thesis presents a comprehensive study on the growth by molecular beam epitaxy (MBE) and the measured Seebeck coefficients and hole transport properties of p‑type oxides, a material class which combines transparency and tunable conductivity. Specifically, Nickel oxide (NiO) and tin monoxide (SnO) were grown by plasma‑assisted MBE using a metal effusion cell and an oxygen plasma. For NiO growth, the focus lies on high temperature growth limits which were determined by the substrate stability of magnesium oxide and gallium nitride. Quality evaluation by Raman spectroscopy for rock‑salt crystal structures is demonstrated. Investigations of NiO doping by surface acceptors and the related surface hole accumulation layer reveal a new doping possibility for p‑type oxides in general. The meta‑stable SnO is stabilized by PAMBE utilizing known growth kinetics of tin dioxide and various in‑situ methods, its application-relevant thermal stability is investigated. Following ex‑situ characterizations by XRD and Raman spectroscopy identify secondary phases and a small growth window for the epitaxial growth of SnO. Electrical measurements confirm the p‑type carriers with promising hole mobilities accessible to Hall measurements. Temperature dependent Hall measurements show band‑like transport indicating a high quality of the grown layers. The functionality of the grown layers is proven by various applications. For example, pn‑heterojunctions were achieved by heteroepitaxial growth of the SnO layers on gallium oxide substrates. The first reported SnO based pn‑junction with an ideality factor below two is accomplished.
Wilson, Nicholas Craig, and nick wilson@csiro au. "An investigation of hybrid density functional theory in the calculation of the structure and properties of transition metal oxides." RMIT University. Applied Sciences, 2009. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20091217.142149.
Повний текст джерелаGrira, Sarra. "Microstructure, texture and superconductive properties of High Temperature Superconducting "HTS" oxides : yBCO thin films and bulk NBCO and YBCO." Thesis, Metz, 2009. http://www.theses.fr/2009METZ005S/document.
Повний текст джерелаThe aim of this work is the study of crystallographic texture and microstructure in connection with the superconducting properties (Tc and Jc) of High Temperature Superconducting (HTS) materials: YBCO and NBCO. Microstructure is studied by X-Ray Diffraction (XRD) and Electron backscatter Diffraction (EBSD). The Determination of critical temperature (Tc) and critical current density (Jc) are made with Superconducting Quantum Interference Device (SQUID) magnetometer or Physical Properties Measurement System (PPMS). The first part of this work investigates the crystallographic textures of the YBCO film by using EBSD in order to deduce the epitaxial relationship between the superconducting layer and the buffer layer. This thin film is made up of three successive deposits (among which 300 nm of YBCO), used in fault current limiters for electrical engineering applications. The second part presents the study of NdBa2Cu3O7-d (NBCO) and YBCO bulks prepared by various techniques. The effect of silver doping of YBCO has been studied on samples prepared by the Melt Textured Growth (MTG) technique under low oxygen partial pressure. The doping up to a given amount of silver enhances the microstructure and the critical current density. A comparison of the physical and structural characteristics between NBCO oxygenated exsitu and YBCO oxygenated in-situ, prepared by MTG under high magnetic field has been made. Zone-melted NBCO samples textured by zone melting method oxygenated respectively in-situ and ex-situ have been studied. These samples exhibit the same texture with the occurrence of twins for the NBCO oxygenated ex-situ
Budde, Melanie [Verfasser]. "Heteroepitaxy, surface- and bulk hole transport, and application of the p-type semiconducting oxides NiO and SnO / Melanie Budde." Berlin : Humboldt-Universität zu Berlin, 2020. http://d-nb.info/122392355X/34.
Повний текст джерелаRichter, Norina Anna [Verfasser], Andreas [Akademischer Betreuer] Knorr, and Matthias [Akademischer Betreuer] Scheffler. "Charged point defects in oxides : a case study of MgO bulk and surface F centers / Norina Anna Richter. Gutachter: Andreas Knorr ; Matthias Scheffler." Berlin : Technische Universität Berlin, 2014. http://d-nb.info/1065665660/34.
Повний текст джерелаKapustin, Yaroslav A. "Forcefield-Based Simulations of Bulk Structure of Mo-V-(Te, Nb)-O M1 Phase Catalysts for Selective Propane Ammoxidation to Acrylonitrile." University of Cincinnati / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1296848202.
Повний текст джерелаNogueira, Deise Cristina Santos [UNESP]. "Mineralogia da fração argila e atributos físicos de um argissolo amarelo." Universidade Estadual Paulista (UNESP), 2017. http://hdl.handle.net/11449/148974.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Nos solos brasileiros, a caulinita, os óxidos de ferro e os hidróxidos de alumínio são alguns dos minerais encontrados na fração argila influenciando o comportamento dos atributos físicos do solo. O objetivo do presente trabalho foi avaliar a influência dos minerais da fração argila nos atributos físicos de um Argissolo Amarelo, submetido a dois tipos de preparo e cultivado com cana-de-açúcar. As amostras deformadas e indeformadas de solo foram coletadas após oito meses do plantio da cana-de-açúcar, em quatro camadas (0,00-0,10, 0,10-0,20, 0,20-0,40 e 0,40-0,60 m) na linha e entrelinha de plantio nas áreas submetidas à escarificação em área total e escarificação na linha da cultura. Através das amostras deformadas determinou-se a textura do solo, ferro extraído por ditionito-citrato-bicarbonato (FeDCB), ferro extraído por oxalato ácido de amônio (FeOAA) e razão caulinita/(caulinita+gibbsita) [(Ct/(Ct+Gb)]. Com as amostras indeformadas determinou-se a densidade do solo (Ds) e a resistência do solo à penetração (RP). Os resultados apresentados pela estatística descritiva demostraram que houve uma separação das áreas de estudo devido à diferença mineralógica encontrada nessas áreas, sendo a primeira área caracterizada pela maior razão Ct/(Ct+Gb) e a segunda área caracterizada pelos maiores teores de ferro extraído por ditionito-citrato-bicarbonato (FeDCB). Pela análise de componentes principais foi possível observar que o FeDCB apresentou correlação inversa com a Ds e a RP, a razão Ct/(Ct+Gb) apresentou correlação direta com os atributos físicos Ds e RP. A mineralogia influenciou o comportamento da densidade do solo e resistência do solo à penetração. A área com maior razão caulinita apresentou maiores valores de densidade do solo e de resistência do solo à penetração e a área com maiores teores de óxidos de ferro apresentou menores valores de densidade do solo e de resistência do solo á penetração. O preparo do solo não influenciou o comportamento da densidade do solo e da resistência do solo à penetração.
In Brazilian soils, kaolinite, iron oxides and aluminium hydroxides are some of the minerals found in the clay fraction influencing the behavior of the soil physical attributes. The objective of the present work was to evaluate the influence of minerals of the clay fraction on the physical attributes of a yellow Ultisol under two tillage and sugar cane cultivation. The disturbed and undisturbed samples of soil were collected in the row and interrow in the areas with chiselling in the total area and chiselling in the planting row in four layers (0,00-0,10, 010-0,20, 0,20-0,40, 0,40-0,60 m) eight months later the sugar cane cultivation. The soil texture, citrate/bicarbonate/dithionite extractable Fe, oxalate/acid/ammonium extractable Fe (FeOAA) and Ct / (Ct+ Gb) ratio were evaluated from disturbed samples and bulk density (Bd) and soil penetration resistance (SPR) were evaluated from undisturbed samples. The results presented by the descriptive statistics showed that there was a separation of the study areas due to the mineralogical difference found in these areas, being the first area characterized by the higher ratio Ct / (Ct + Gb) and the second area characterized by the higher citrate/bicarbonate/dithionite extractable Fe (FeDCB). In the principal component analysis, it was observed that the FeDCB showed an inverse correlation between Bd and SPR. It was also observed that the Ct / (Ct + Gb) ratio showed a direct correlation with the physical attributes Bd and SRP. The mineralogy influenced the behavior of the Bd and SPR. The area with higher Ct/ (Ct+Gb) ratio, showed higher values of Bd and SRP and The area with higher content of iron oxides had lower values of Bd and SRP. The soil tillage didn’t influence the behavior of Bd and SPR.
FAPESP: 2014/14490-2
Allen, Martin Ward. "Schottky Contact Formation to Bulk Zinc Oxide." Thesis, University of Canterbury. Electrical and Computer Engineering, 2008. http://hdl.handle.net/10092/4385.
Повний текст джерелаREMONDINA, JACOPO. "Ga-rich oxide-in-oxide glass ceramics: from bulk to thin film devices." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2020. http://hdl.handle.net/10281/263429.
Повний текст джерелаIn this thesis I present the work I have carried out during my PhD on Ga-oxide containing nanostructured glass-ceramic films as a potential breakthrough for the implementation of this class of material in planar geometry for applications in the field of optoelectronics. In the last three years, my investigations have been aimed at understanding the relationship between the occurrence of nanostructuring – analysed through a detailed structural studies by means of different microscopy and diffractometric techniques as a function of deposition conditions and post-deposition treatments – and the physical mechanisms of charge transport and polarization taking place in oxide-in-oxide films. The studied material was produced by RF sputtering deposition starting from a glass target of Li, Na, Si, Ga and Ge mixed oxide. As a consequence of the deposition process we have obtained partially crystallized material with Ga-rich nanocrystals incorporated in the remaining amorphous matrix. Through atomic force microscopy, x-ray reflectivity, 2D-x-ray diffraction, 2D-small angle x-ray scattering - also employing synchrotron radiation facilities - we have fully characterized the nanostructured films at different length scales, from few nm to few microns. The detailed analysis of the results shows the formation of multiple anisotropic spinel Ga-oxide nanocrystals with size of about 3 nm, forming larger lenticular aggregates with significant differences between the in-plane and the out-of-plane dimensions. As a result of the investigation of differently treated samples, the study also shows that size distribution and morphology of the nanostructures can be controlled by deposition conditions, duration and temperature of post-deposition thermal treatments. Starting from the knowledge of the structural features, the research activity has been directed to the deep understanding of the charge transport properties resulting from the nanostructured nature of the material, including the Ga2O3 semiconductor nanophase and the dielectric host matrix. The electrical response – analysed with the aid of complex impedance spectroscopy – turns out to be the results of multiple contributions to transport and charging mechanisms by the matrix and the nanophase, including the effects of the internal interfaces. The data suggest that the charge transport is sustained by a combination of thermally activated hopping and tunnelling mechanisms mediated by the percolation path built up by the nanostructured features of the material. Interestingly, the overall response gives preliminary evidences of electrical plasticity, making nano-glassceramic thin films potential candidates as key systems in advanced devices for brain-inspired oxide-in-oxide fully inorganic memories.
Miller, Paul. "Zinc Oxide: A spectroscopic investigation of bulk crystals and thin films." Thesis, University of Canterbury. Physics and Astronomy, 2008. http://hdl.handle.net/10092/3618.
Повний текст джерелаManton, Stephen John. "Fabrication and characterisation of high temperature superconducting bulk YBCO." Thesis, University of Southampton, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.396128.
Повний текст джерелаWarburton, Toby James. "Lasers and amplifiers in bulk and planar waveguide oxide crystals." Thesis, University of Southampton, 1997. https://eprints.soton.ac.uk/399481/.
Повний текст джерелаSo, Chun-keung. "Defect study of zinc oxide bulk materials by positron lifetime spectroscopy." Click to view the E-thesis via HKUTO, 2008. http://sunzi.lib.hku.hk/HKUTO/record/B39558691.
Повний текст джерелаWeston, Leigh. "First-Principles Theoretical Studies of Bulk, Defect and Interface properties of Oxide Semiconductors." Thesis, The University of Sydney, 2015. http://hdl.handle.net/2123/13806.
Повний текст джерела蘇振強 and Chun-keung So. "Defect study of zinc oxide bulk materials by positron lifetime spectroscopy." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2008. http://hub.hku.hk/bib/B39558691.
Повний текст джерелаMurali, Raghunath. "Scaling opportunities for bulk accumulation and inversion MOSFETs for gigascale integration." Diss., Available online, Georgia Institute of Technology, 2004:, 2004. http://etd.gatech.edu/theses/submitted/etd-02132004-173432/unrestricted/murali%5FRaghunath%5F405%5F.pdf.
Повний текст джерелаHess, Dennis, Committee Member; Meindl, James, Committee Chair; Allen, Phillip, Committee Member; Cressler, John, Committee Member; Davis, Jeffrey, Committee Member. Vita. Includes bibliographical references (leaves 108-119).
Volodin, A. A., P. V. Fursikov, Y. M. Shulga, I. I. Khodos, M. N. Abdusalyamova, and B. R. Tarasov. "Morphology of Nanostructured Alumina and Lanthana Synthesized with the Use of Fibrous Organic Matrix." Thesis, Sumy State University, 2012. http://essuir.sumdu.edu.ua/handle/123456789/35041.
Повний текст джерелаWu, Zhenghui. "Impact of metal oxide/bulk-heterojunction interface on performance of organic solar cells." HKBU Institutional Repository, 2015. https://repository.hkbu.edu.hk/etd_oa/159.
Повний текст джерелаHu, Anyang. "Investigating the interfacial process and bulk electrode chemistry in tungsten oxide electrochromic materials." Thesis, Virginia Tech, 2020. http://hdl.handle.net/10919/100613.
Повний текст джерелаM.S.
With the rapid development of human society, the research of new energy-saving materials has become a focus of attention. Among them, electrochromic devices can effectively adjust their color through a controllable electrochemical reaction and have a wide range of uses in our daily life. For example, smart windows can reduce glare and heat without blocking the natural light, thereby providing buildings and vehicles with better thermal and visual comfort. Electrochromic optical displays can lower energy consumption. Variable reflectance mirrors such as anti-glare car rear-view mirrors can ensure the safety of driving. Lastly, wearable apparel such as electrochromic lenses for spectacles and sunglasses can protect users from ultraviolet radiation. Although electrochromic materials and devices have not expanded from the niche market, the enormous potential that they hold cannot be ignored and wide-scale commercialization should be sought after. Tungsten oxides electrochromic devices have proved to utilize the full spectrum of the incident light through structure design. These devices can also be configured with solar cells as a state-of-art integrated self-powered system with satisfactory optical modulation that can be obtained without any external electrical energy input. Moreover, WO3-based devices have also been combined with electrodeposition technology to achieve fast color-switching kinetics. However, the long-term durability in the acidic electrolyte under electrochemical cycling conditions needs to be further improved, and the road of full commercialization is still unpaved. To design high-performance electrochromic materials, it is imperative to study the degradation mechanism under long-term electrochemical cycling conditions. In the present thesis, the performance degradation of the WO3 electrode in acid electrolytes involves chemical changes. Through a better understanding of the fundamental degradation process, the design of high- performance electrochromic metal oxides can be developed.
Kernan, Forest Emerson. "Material Characterization of Zinc Oxide in Bulk and Nanowire Form at Terahertz Frequencies." PDXScholar, 2012. https://pdxscholar.library.pdx.edu/open_access_etds/510.
Повний текст джерелаHughes, William L. "Synthesis and characterization of zinc oxide nanostructures for piezoelectric applications." Diss., Available online, Georgia Institute of Technology, 2006, 2006. http://etd.gatech.edu/theses/available/etd-08232006-155547/.
Повний текст джерелаWang, Zhong Lin, Committee Chair ; Wong, C.P., Committee Member ; Summers, Christopher J., Committee Member ; Degertekin, F. Levent, Committee Member ; Bottomley, Lawrence A., Committee Member.
Pinkett, Shawn L. "Techniques to facilitate the fabrication of ZnO-based thin film bulk acoustic wave devices." Diss., Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/14889.
Повний текст джерелаNdoye, Coumba. "Characterization of Dopant Diffusion in Bulk and lower dimensional Silicon Structures." Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/46321.
Повний текст джерелаMaster of Science
Kumar, Santosh. "DENSITY-FUNCTIONAL THEORY APPLIED TO PROBLEMS IN CATALYSIS AND ELECTROCHEMISTRY." Master's thesis, University of Central Florida, 2006. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2807.
Повний текст джерелаM.S.
Department of Mechanical, Materials and Aerospace Engineering;
Engineering and Computer Science
Materials Science and Engineering
Arbintarso, Ellyawan Setyo. "Bulk and grain boundary electrical behaviours in Nb and Sn doped calcium copper titanium oxide." Thesis, University of Manchester, 2014. https://www.research.manchester.ac.uk/portal/en/theses/bulk-and-grain-boundary-electrical-behaviours-in-nb-and-sn-doped-calcium-copper-titanium-oxide(1f44d210-e3a7-470f-ba26-d1966e0f60c3).html.
Повний текст джерелаEriksson, Tom. "LiMn2O4 as a Li-ion Battery Cathode. From Bulk to Electrolyte Interface." Doctoral thesis, Uppsala universitet, Institutionen för materialkemi, 2001. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-1397.
Повний текст джерелаRödel, Eva. "In situ bulk structural investigation of Mo5O14-type mixed metal oxide catalysts for partial oxidation reactions." [S.l.] : [s.n.], 2006. http://opus.kobv.de/tuberlin/volltexte/2007/1473.
Повний текст джерелаHerting, Gunilla. "Bioaccessibility of Stainless Steels : Importance of Bulk and Surface Features." Doctoral thesis, KTH, Korrosionslära, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4773.
Повний текст джерелаQC 20100810
Akinyemi, Segun Ajayi. "Geochemical and mineralogical evaluation of toxic contaminants mobility in weathered coal fly ash: as a case study, Tutuka dump site, South Africa." Thesis, University of the Western Cape, 2011. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_1226_1360593017.
Повний текст джерелаThe management and disposal of huge volumes of coal combustion by products such as fly ash has constituted a major challenge to the environment. In most cases due to the inadequate alternative use of coal fly ash, the discarded waste is stored in holding ponds, slag heaps, or stock piled in ash dumps. This practice has raised concerns on the prospect of inorganic metals release to the surface and groundwater in the vicinity of the ash dump. Acceptable scientific studies are lacking to determine the best ash disposal practices. Moreover, knowledge about the mobility patterns of inorganic species as a function of mineralogical association or pH susceptibility of the dry disposed ash dump under natural weathering conditions are scarce in the literature. Fundamental understanding of chemical interactions of dry disposed ash with ingressed CO2 from atmosphere, percolating rain water and brine irrigation within ash disposal sites were seen as key areas requiring investigation. The mineralogical association of inorganic species in the dry disposed ash cores can be identified and quantified. This would provide a basis for understanding of chemical weathering, mineralogical transformations or mobility patterns of these inorganic species in the dry ash disposal scenario. The current study therefore aims to provide a comprehensive characterisation of weathered dry disposed ash cores, to reveal mobility patterns of chemical species as a function of depth and age of ash, with a view to assessing the potential environmental impacts. Fifty-nine samples were taken from 3 drilled cores obtained respectively from the 1 year, 8 year and 20-year-old sections of sequentially dumped, 
weathered, dry disposed ash in an ash dump site at Tutuka - a South African coal burning power station. The core samples were characterized using standard analytical procedures viz: X-ray fluorescence (XRF), X-ray diffraction (XRD), Fourier transforms infrared (FTIR) techniques, Scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) and Acid neutralisation capacity (ANC) test. A modified sequential extraction (SE) method was used in this study. The chemical partitioning, mobility and weathering patterns in 1 year, 8 year and 20-year-old sections of the ash dump were respectively investigated using this modified sequential extraction scheme. The sequence of the extractions was as follows: (1) water soluble, (2) exchangeable, (3) carbonate, (4) iron and manganese and (5) residual. The results obtained from the 5 steps sequential extraction scheme were validated with the total metal content of the original sample using mass balance method. The distribution of major and trace elements in the different liquid fractions obtained after each step of sequential extraction of the 59 drilled core samples was determined by inductively coupled plasma mass spectrometry (ICPMS). The data generated for various ash core samples were explored for the systematic analysis of mineralogical transformation and change in ash chemistry with ageing of the ash. Furthermore, the data was analyzed to reveal the impact of ingressed CO2 from atmosphere, infiltrating rain water and brine irrigation on the chemistry of ash core samples. Major mineral phases in original ash core samples prior to extraction are quartz (SiO2) and mullite (3Al2O3·
2SiO2). Other minor mineral phases identified were hematite (Fe2O3), calcite (CaCO3), lime (CaO), anorthite (CaAl2Si2O8), mica (Ca (Mg, Al)3 (Al3Si) O10 (OH)2), and enstatite (Mg2Si2O6). X-ray diffraction results show significant loss of crystallinity in the older ash cores. The presence of minor phases of calcite and mica in dry disposed ash cores are attributed to reduction in the pore water pH due to hydration, carbonation and pozzolanic reactions. The X-ray diffraction technique was unable to detect Fe-oxyhydroxide phase and morealuminosilicate phases in ash core samples due to their low abundance and amorphous character. X-ray fluorescence results of the original ash core samples showed the presence of major oxides, such as SiO2, Al2O3, Fe2O3, while CaO, K2O, TiO2, Na2O, MnO, MgO, P2O5, and SO3 occur in minor concentrations. The ratio of SiO2/Al2O3 classified the original core samples prior to extraction as a silico-aluminate class F fly ash. The ternary plot of major elements in 1-year-old ash core samples was both sialic and ferrocalsialic but 8 year and 20-year-old ash core samples were sialic in chemical composition. It is noteworthy that the mass % of SiO2 varies through the depth of the core with an increase of nearly 3 %, to 58 mass % of SiO2 at a depth of 6 m in the 1-year-old core whereas in the case of the 8-year-old core a 2 % increase of SiO2 to a level of 57.5 mass % can be observed at levels between 4-8 m, showing dissolution of major components in the matrix of older ash cores.. The Na2O content of the Tutuka ash cores was low and varied between 0.6-1.1 mass % for 1-year-old ash cores to around 0.6-0.8 mass % for 8-year-old ash cores. Sodium levels were higher in 1-year-old ash cores compared to 8 year and 20-year-old ashcores. Observed trends indicate that quick weathering of the ash (within a year) leached out Na+ from the ash dump. No evidence of Na+ encapsulation even though the ash dump was brine irrigated. Thus the dry disposal ash placement method does not result in a sustainable salt sink for Na-containing species over time. The total content of each of the elements in 1 year and 20-year-old ash cores was normalised with their total content in fresh ash from same power station to show enrichment and depletion factor. Major elements such as K+, Mn showed enrichment in 1-year-old ash cores whereas Al, Si, Na+, Ti, Ca, Mg, S and Fe showed depletion due to over time erosion. Trace elements such as Cr, Sr, P, Ba, Pb, V and Zn showed enrichment but Ni, Y, Zr showed depletion attributed to over time erosion. In 20-year-old ash cores, major elements such as Al, Na+ and Mn showed enrichment while Si, K+, Fe, Mg and Ca showed depletion highlighting their mobility. Trends indicated intensive flushing of major soluble components such as buffering constituents (CaO) by percolating rain water. The 1-year-old and 20-year-old coal ash cores showed a lower pH and greater loss/depletion of the soluble buffering constituents than the 2-week-old placed ash, indicating significant chemical weathering within a year. Based 
on ANC results the leaching behaviours of Ca, Mg, Na+, K+, Se, Cr, and Sr were found to be controlled by the pH of the leachant indicating high mobility of major soluble species in the ash cores when in contact with slightly acid rain water. Other investigated toxic metals such as As, Mo and Pb showed amphoteric behaviour with respect to the pH of the leachant. Chemical alterations and formation of transient minor secondary mineral phases was found to have a significant effect on the acid susceptibility and depletion pattern of chemical species in the core ash samples when compared to fresh ash. These ANC results correlated well with the data generated from the sequential extraction scheme. Based on sequential extraction results elements, showed noticeable mobility in the water soluble, exchangeable and carbonate fractions due to adsorption and desorption caused by variations in the pore water pH. In contrast, slight mobility of elements in the Fe and Mn, and residual fractions of dry disposed fly ashes are attributed to the co-precipitation and dissolution of minor amount of less soluble secondary phase overtime. The 1-year-old dry disposed ash cores were the least weathered among the 3 drilled ash cores. Therefore low concentration of toxic metals in older ash cores were ascribed to extensive weathering with slower release from residual mineral phases over time. Elements were found to associate with different mineral phases depending on the age or depth of the core samples showing greater heterogeneity in dispersion. For instance the average amount of total calcium in different mineral associations of 1-year-old ash cores is as follows
water soluble (10.2 %), exchangeable (37.04 %), carbonate (37.9 %), Fe and Mn (7.1 %) and residual (2.97 %). The amount of total Na+ in different mineral phases of 1-year-old ash cores followed this trend: water soluble (21 %), exchangeable (11.26 %), carbonate (2.6 %), Fe and Mn (4.7 %) and residual (53.9 %). The non-leachable portion of the total Na+ content (namely that contained in the residual fraction) in the 1-year-old ash core samples under conditions found in nature ranged between 5-91 %. This non-leachable portion of the Na+ showed the metastability of the mineral phases with which residual Na+ associates. Results showed older ash cores are enriched in toxic elements. Toxic elements such as As, B, Cr, Mo and Pb are enriched in the residual fraction of older ash cores. For instance As concentration in the residual fraction varied between 0.0003- 0.00043 mg kg-1 for 1-year-old ash cores to around 0.0003-0.0015 mg kg-1 for 20-year-old ash cores. This suggests that the older ash is enriched in toxic elements hence dust from the ash dump would be toxic to human health. The knowledge of mobility and ecotoxicological significance of coal fly ash is needed when considering its disposal or reuse in the environment. The mobility and ecotoxicology of inorganic metals in coal fly ash are determined by (i) mineralogical associations of inorganic species (ii) in-homogeneity in the ash dumps (iii) long and short term exposure to ingress CO2 and percolating rain water. Management issues such as inconsistent placement of ash in the dumps, poor choice of ash dump site, in-homogeneity in brine irrigation, no record of salt load put on the ash dumps and lack of proper monitoring requires improvement. The thesis provides justification for the use of the modified sequential extraction scheme as a predictive tool and could be employed in a similar research work. This thesis also proved that the dry ash disposal method was not environmental friendly in terms of overall leaching potential after significant chemical weathering. Moreover the study proved that the practice of brine co-disposal or irrigation on ash dumps is not sustainable as the ash dump did not act as a salt sink.
Lawrence, P. J. "The role of defects and impurities at surfaces, interfaces and in the bulk of chromium(III) oxide." Thesis, University of Bath, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384627.
Повний текст джерелаZhou, Yi Park Minseo. "Bulk gallium nitride based electronic devices Schottky diodes, Schottky-type ultraviolet photodetectors and metal-oxide-semiconductor capacitors /." Auburn, Ala., 2007. http://hdl.handle.net/10415/1401.
Повний текст джерелаOlson, Grant T. "Improving Hybrid Solar Cells: Overcoming Charge Extraction Issues In Bulk Mixtures of Polythiophenes and Zinc Oxide Nanostructures." DigitalCommons@CalPoly, 2014. https://digitalcommons.calpoly.edu/theses/1257.
Повний текст джерелаAugustine, B. (Bobins). "Efficiency and stability studies for organic bulk heterojunction solar cells." Doctoral thesis, Oulun yliopisto, 2016. http://urn.fi/urn:isbn:9789526214436.
Повний текст джерелаTiivistelmä Orgaanisten heteroliitosaurinkokennojen kerrosrakenteen ominaisuudet ja laatu vaikuttavat merkittävästi aurinkokennojen toiminnallisuuteen. Erityisesti rakenteelliset epähomogeenisuudet aktiivi- ja puskurikerroksissa heikentävät kennon hyötysuhdetta. Kennojen stabiilisuutta tarkasteltaessa myös mekaanisella rasituksella, pitkittyneellä lämpöaltistuksella ja materiaalien reagoinneilla keskenään kerrosten välillä, on selkeä negatiivinen vaikutus kennojen stabiilisuuteen. Orgaanisen aurinkokennoteknologian kaupallistamisen rajoitteina ovat kennojen heikko hyötysuhde ja stabiilisuus, joten menetelmät jotka tarjoavat ratkaisuja edellä mainittuihin ongelmiin, ovat erittäin tärkeitä teknologiaa kaupallistavalle teollisuudelle. Tämä väitöskirja keskittyy johdonmukaisesti selvittämään tapoja, joilla voidaan parantaa heteroliitosaurinkokennojen hyötysuhdetta ja elinikää. Hyötysuhteen tehostamiseksi valittiin kaksi eri lähestymistapaa, joista ensimmäisessä keskityttiin aktiivikerroksen morfologian parantamiseen ja toisessa aukkoja kuljettavan kerroksen sähköisten ominaisuuksien parantamiseen lämpökäsittelyprosessin avulla. Sopivan lisäaineen avulla aktiivikerroksen ei-toivottua kiteytymistä voidaan pienentää ja parantaa näin kerroksen morfologiaa. Lisäksi työssä todettiin, että lämpökäsittelyn aikaisella ympäristöolosuhteella (ilma, typpi, tyhjiö) on merkittävä vaikutus puskurikerroksen optimaaliseen toimintaan aurinkokennossa. Stabiilisuuden parantamiseksi kehitettiin välikerroksen hyödyntämiseen perustuva menetelmä, jolla voidaan tehokkaasti vähentää kennojen sisäisessä rakenteessa tapahtuvaa toiminnallisuuden heikkenemistä, joka aiheutuu aukkoja kuljettavan kerroksen syövyttävästä vaikutuksesta indiumtinaoksidi (ITO) pohjaiseen anodiin. Tämän lisäksi työssä tutkittiin kokeellisesti stabiilisuuteen heikentävästi vaikuttavia tekijöitä, kuten mekaanisen rasituksen aiheuttamia vaurioita metallioksidi (ITO) anodissa ja lämpöaltistuksesta aiheutuvia vikoja polymeeri-fullereeni rakenteeseen perustuvassa aktiivikerroksessa. Tutkimuksen keskeisin tulos on, että esitellyt keinot aurinkokennojen hyötysuhteen ja stabiilisuuden parantamiseen ovat edullisia, tehokkaita ja helppoja hyödyntää. Tulokset voivat merkittävästi edistää orgaanisten aurinkokennojen teknistä kehitystä ja kiihdyttää niiden tuloa kaupallisiksi tuotteiksi
POLO, ANNALISA. "TERNARY OXIDE SEMICONDUCTOR PHOTOANODES FOR SOLAR ENERGY CONVERSION." Doctoral thesis, Università degli Studi di Milano, 2021. http://hdl.handle.net/2434/827287.
Повний текст джерелаKerr, Mark John, and Mark Kerr@originenergy com au. "Surface, Emitter and Bulk Recombination in Silicon and Development of Silicon Nitride Passivated Solar Cells." The Australian National University. Faculty of Engineering and Information Technology, 2002. http://thesis.anu.edu.au./public/adt-ANU20040527.152717.
Повний текст джерелаMarana, Naiara Letícia. "Estudo computacional do óxido de zinco puro e dopado com metais de transição : bulk, superfícies, interfaces e nanotubos /." Bauru, 2017. http://hdl.handle.net/11449/150977.
Повний текст джерелаBanca: Miguel Angel San-Miguel Barrera
Banca: Rogério Custódio
Banca: Ieda Maria Garcia dos Santos
Banca: Luis Vicente de Andrade Scalvi
Resumo: A química computacional tem se mostrado uma ferramenta muito útil no meio científico e tem sido cada vez mais utilizada na pesquisa de novos materiais. Dentre os muitos sistemas estudados com o auxílio da química computacional, destaca-se o óxido de zinco (ZnO), muito utilizado em diversos dispositivos eletrônicos tais como, sensores, células solares, diodos de emissão de luz UV e diodos a laser. À temperatura e pressão ambientes, a estrutura cristalina mais estável do ZnO é hexagonal do tipo wurtzita, na qual os átomos de zinco estão coordenados a quatro átomos de oxigênio. Devido a coordenação tetraédrica e falta de centro de simetria dessa estrutura, o ZnO apresenta propriedades piezoelétricas podendo ser aplicado em sensores piezoelétricos, por exemplo. Atualmente, existem muitos trabalhos científicos relacionados com o ZnO, porém o número de trabalhos teóricos em relação aos trabalhos experimentais ainda é pequeno. Neste sentido, este projeto teve como objetivo a análise das propriedades do ZnO em três morfologias diferentes, bulk, superfícies e nanotubos, aplicando as principais técnicas de modelagem computacional aplicada ao estado sólido tais como escolha do funcional de densidade e funções de base, otimização da geometria, dopagem por substituição de átomos, cálculo de constantes elásticas e piezoelétricas, simulação de pressão hidrostática aplicada a célula unitária, secção do bulk para gerar superfícies, substituição de átomos para formar interfaces, nanotubos e ad... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Computacional chemistry has proved to be a very useful tool in the scientific field and has been incrasingly used in the research of new materials. Among the many systems studied with the aid of computacional chemistry, we highlight zinc oxide (ZnO), widely used in many electronic devices such as sensors, solar cells, UV light emitting diodes and laser diodes. At room temperature and pressure, the most stable crystalline structure of ZnO is hexagonal of the wurtzite type, in the zinc atoms are coordinated to four oxygen atoms. Due to the tetrahedral coordination and lack of center of symmetry of this structure, the ZnO presents piezoelectric properties and can be applied in piezoelectric sensors, for example. Currently, there are many papers related to ZnO, however the number of theoretical articles in relation to the experimental works are still small. In this sense, this project aimed the analysis of ZnO properties in three different morphologies, bulk, surfaces and nanotubes, applying the main techniques of computational modeling to solid state such as the choise of density functional and basic functions, optimization of geometry, doping by atom replacement, calculation of elastic and piezoelectric constants, hydrostatic pressure simulation applied to unit cell, bulk section to generate surfaces, replacement of atoms to form interfaces, nanotubes and adsorption of molecules in nanotubes. The calculations were performed applying th Density Functional Theory, with the help of the CRYSTAL14 program, using the hybrid function B3LYP, with the ste of all-electron base functions. The applied methodology preserves the periodicity of the crystalline system (1D for nanotubes, 2D for surfaces or 3D for bulk), in which the building blocks are composed of unit cells and can be replicanted by the symmetry operator. The topological reviews were performed applying the Quantum Theory... (Complete abstract electronic access below)
Doutor
Wang, Zixin. "TOWARDS HIGH-PERFORMANCE PEROVSKITE SOLAR CELLS BY CATHODE INTERFACIAL ENGINEERING WITH TERNARY METAL OXIDE AND DEVICE ENGINEERING WITH BULK HETROJUNCTION." University of Akron / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron149520580193777.
Повний текст джерелаEriksson, Tom. "LiMn2O4 as a Li-ion Battery Cathode. From Bulk to Electrolyte Interface." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2001. http://publications.uu.se/theses/91-554-5100-4/.
Повний текст джерелаWoo, Jungwon. "Bulk and Surface Characteristics of Model M1 and M2 Phase Catalysts for Propane Ammoxidation to Acrylonitrile." University of Cincinnati / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1445615206.
Повний текст джерелаBurk, Bettina [Verfasser]. "Entwicklung neuer Flammschutzmittel basierend auf Derivaten des 9,10-Dihydro-10-oxaphosphaphenanthren-10-oxids / Bettina Burk." München : Verlag Dr. Hut, 2016. http://d-nb.info/109411765X/34.
Повний текст джерелаBurk, Bettina Susanne Ulrike [Verfasser]. "Entwicklung neuer Flammschutzmittel basierend auf Derivaten des 9,10-Dihydro-10-oxaphosphaphenanthren-10-oxids / Bettina Burk." München : Verlag Dr. Hut, 2016. http://nbn-resolving.de/urn:nbn:de:101:1-2016032518428.
Повний текст джерелаPaula, Priscila Marques Naves de. "Análises das propriedades ópticas, morfológicas e estruturais de pontos quânticos de PbS sintetizados a partir de diferentes concentrações de dopantes." Universidade Federal de Uberlândia, 2006. https://repositorio.ufu.br/handle/123456789/15662.
Повний текст джерелаPbS quantum dots has been grown in oxide glasses by two distinct methodologies according to the dopants, using the fusing method at 1200ºC. The host glass matrices used were SNAB (SiO2.Na2CO3.Al2O3.B2O3) and SNABP (SiO2.Na2CO3.Al2O3.B2O3.PbO2), with PbS bulk and S (sulphur) added as dopants, respectively. Thermal treatments were applied in a systematic way in order to allow a controlled growth of quantum dots. Different experimental techniques were realized in order to study the growth kinetic of dots as a function of thermal treatment times and dopant concentrations. It was analyzed thermal properties of the glass matrices by Calorimetry Scanning Diferencial (DSC). Many techniques have allowed discussion of the optical properties by Optical Absorption (OA) and Photoluminescence (PL), morphologic properties by Atomic Force Microscopy (AFM), and structural properties by X-Ray Diffractometry (DRX) of the nanocrystals. Qualitative and quantitative analyse of the chemical composition of the samples has been possible by spectrometry of Fluorescence of Raios-X (FRX). Using the ] 4 4 [ . × p k r r method we were able to estimate the avarage diameter of the PbS quantum dots. Calculations of dispersion sizes of PbS quantum dots, from the AO bands, has been presented. We have found the dependence between the quantum dot gap and the dopant concentrations. The relation between the Stokes Shift and the average size of the PbS quantum dots was also presented. Through the previous results, we have defined the methodology referring the host glass matrix SNABP with S bulk added as the most favorable to the growth PbS quantum dots with low size dispersion.
Pontos Quânticos de PbS foram sintetizados em vidros à base de óxidos, a partir duas metodologias distintas quanto a dopagens, pelo método da fusão a 1200ºC. As matrizes vítreas hospedeiras utilizadas foram: SNAB (SiO2.Na2CO3.Al2O3.B2O3) e SNABP (SiO2.Na2CO3.Al2O3.B2O3.PbO2), e os dopantes adicionados à elas foram PbS bulk e S (enxôfre), respectivamente. Tratamentos Térmicos variados e adequados foram efetuados nestas amostras para permitir o crescimento controlado dos pontos quânticos de PbS. Com o objetivo de estudar e acompanhar a cinética de crescimento destes pontos em função dos tempos de tratamentos térmicos e das variadas concentrações de dopantes, foram efetuadas várias técnicas de caracterizações. Estas permitiram análises das propriedades térmicas dos vidros por Calorimetria Exploratória Diferencial (DSC); ópticas, por Absorção Óptica (AO) e Fotoluminescência (PL); morfológicas, por Imagens de Microscopia de Força Atômica (AFM); e estruturais, por Difratometria de Raios-X (DRX) dos referidos nanocristais. Análises qualitativas e quantitativas das composições químicas das amostras sintetizadas neste trabalho foram possíveis através da técnica de espectrometria de Fluorescência de Raios-X (FRX). Com o auxilio do método ] 4 4 [ . × p k r r , foi possível estimar o diâmetro médio dos pontos quânticos de PbS. Cálculos de dispersão de tamanhos ξ a partir da largura a meia altura (W) das bandas de AO e discussões sobre a dependência de energia e o tamanho médio dos pontos quânticos foram apresentados e discutidos. Mostrouse graficamente a relação de dependência entre o Gap dos pontos quânticos e as concentrações de dopantes adicionados às matrizes vítreas. Apresentou-se de forma gráfica a relação entre o deslocamento Stokes e o tamanho médio dos pontos quânticos de PbS. A partir de análises dos resultados obtidos, definiu-se então a metodologia correspondente à matriz SNABP dopada com S bulk como sendo a mais favorável para a formação e crescimento dos pontos quânticos de PbS com menor dispersão de tamanhos entre si.
Mestre em Física
Nebatti, Ech-Chergui Abdelkader [Verfasser], Burak [Akademischer Betreuer] Atakan, and Volker [Akademischer Betreuer] Buck. "Functional doped metal oxide films : [[Elektronische Ressource]] : Zinc oxide (ZnO) as transparent conducting oxide (TCO) Titanium dioxide (TiO2) as thermographic phosphor and protective coating / Abdelkader Nebatti Ech-Chergui. Gutachter: Volker Buck. Betreuer: Burak Atakan." Duisburg, 2011. http://d-nb.info/1015428088/34.
Повний текст джерелаChakravarty, Somik. "Mechanical properties of cohesionless and cohesive bulk solids : transition from non-cohesive to cohesive powders." Thesis, Compiègne, 2018. http://www.theses.fr/2018COMP2423.
Повний текст джерелаHandling and processing of granular material release fine solid dust particles, which in an occupational setting, can severely affect worker health & safety and the overall plant operation. Dustiness or the ability of a material to release dust particles depends on several material and process parameters and is usually measured by lab-scale dustiness testers. Dustiness tests remain mostly experimental studies and lack reliable predictive ability due to limited understanding of the dust generation mechanisms and the complex interactions between the particles, wall and fluid, occurring simultaneously during dust generation. In the framework of EU ITN project T-MAPPP, this thesis uses an experimental approach to understand the dust generation mechanisms by studying: a) the effects of key bulk and particle properties on powder dustiness; b) the nature and magnitude of inter-particle, particle-wall and particle-fluid interactions; c) the evolution of dustiness and generation mechanisms for long duration powder applications. The results indicate that the dust generation mechanisms differ based on particle size and size distribution of the powder. For the given test samples and experimental conditions, the differences in powder dustiness and dust emission patterns can be characterized by three different groups of powders; powders containing fine cohesive particles, bi-modal (consisting of fine and large particles) powders and lastly, powders consisting of only large particles. While bulk cohesion, especially that stemming from van der Waals forces (measured using shear testers) determines the level of dustiness for the fine powders (in such a way that higher bulk cohesion leads to lower dustiness), both the fraction of fine particles and cohesion determine the dustiness of bi-modal powders. The large particles can emit dust only through attrition of the primary particles into smaller aerosolizable fine particles. Analysis of a traced particle motion inside a cylindrical tube agitated by a vortex shaker dustiness tester shows the cyclic nature of the particle motion. The motion (position and velocity) is symmetric and isotropic in the horizontal plane with lowest radial velocities close to the tube centre and highest at the boundary wall of the test tube. The particles tend to rise up slowly in the middle of the tube while descending rapidly close to the wall. The highest values of the velocity are found at the highest heights and close to the wall of the test tube, where the population densities are lowest. Increasing particle size and vortex rotation speeds tends to increase particle velocity whereas increase in powder mass leads to a decrease in particle velocity for rotation speeds up to 1500 rpm. For the given samples (silicon carbide, alumina and acetylene coke) and the experimental conditions, the initial dustiness is determined by the fraction of fine respirable particles present in the powder but the long-term dust generation patterns and levels are influenced by the material attrition behaviour. Dust is generated by the fragmentation and/or abrasion of primary particles, which may lead to the production and emission of fine daughter particles as dust. The samples with large irregularly shaped particles are likely to show high dustiness by shedding angular corners through inter-particle and particle-wall collisions, thus becoming more spherical in shape. On the contrary, the smaller particles are more resistant to abrasion and generate relatively less dust. While the vortex shaker dustiness tests show similar trends as an attrition tester, our study using alumina and acetylene coke indicate that the results are not interchangeable. Results from this thesis help understand the influence of powder and process parameters which may be manipulated to reduce dust generation. Furthermore, experimental results can be used to develop and validate numerical models to predict dustiness
Crnogorac, Nebojša [Verfasser], Jörn [Akademischer Betreuer] Sesterhenn, and Roberto [Akademischer Betreuer] Fornari. "Numerical analysis of hydrodynamic stability in the melt during the Czochralski crystal growth of oxide bulk crystals / Nebojša Crnogorac. Gutachter: Jörn Sesterhenn ; Roberto Fornari. Betreuer: Jörn Sesterhenn." Berlin : Technische Universität Berlin, 2013. http://d-nb.info/1065665598/34.
Повний текст джерела