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1
Gullayanon, Rutchanee. "A calibration methodology for energy dispersive X-ray fluorescence measurements based upon synthetically generated reference spectra." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/42771.
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This research developed an on-line measurement systemfor determining the amount of fluorochemicals on carpet fibers using energy-dispersive X-ray fluorescence (EDXRF).This system is designed as a complementary tool to an existingchemical burn test certified by the American Association ofTextile Chemists and Colorists (AATCC), which is performed off-line on randomly selected carpet samples and time consuming.This research reviewed XRF principles and determined parameters that affect XRF spectra such as measurement time, measurement number, X-ray tube voltage, X-ray tube current, primary beam filter, and carpet characteristics. For this application, XRF calibrations must be performed for carpets of all styles and types. However, preparing actual carpet calibration samples is expensive. This research introduced a methodology to synthetically generate reference spectra using XRF spectra from standard fluorochemical stock solution samples and from base carpet samples for each carpet type to be tested. Thus, actual, physical standards are not required for each carpet type or style. This study showed that the synthetically generated XRF spectra alone were not always sufficient to guarantee the confidence interval required by the certified AATCC test. Thus, it is recommended that for on-line implementation, burn test results should be used to create a historical data base for each carpet type to reduce margin of error for calibrations generated from the synthetic spectra.
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Chisholm, Daniel J. "Use of Principle Component Analysis for the identification and mapping of phases from energy-dispersive x-ray spectra." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1999. http://handle.dtic.mil/100.2/ADA359572.
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Nasser, Hisham. "Thermally Stimulated Current Study Of Traps Distribution In Tlgases Layered Single Crystals." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/3/12611866/index.pdf.
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Trapping centres and their distributions in as-grown TlGaSeS layered single
crystals were studied using thermally stimulated current (TSC) measurements.
The investigations were performed in the temperature range of 10&ndash<br>160 K with
various heating rates between 0.6&ndash<br>1.2 K/s. Experimental evidence has been
found for the presence of three electrons trapping centres with activation
energies 12, 20, and 49 meV and one hole trapping centre located at 12 meV.
Their capture cross-sections and concentrations were also determined. It is
concluded that in these centres retrapping is negligible as confirmed by the good
agreement between the experimental results and the theoretical predictions of
the model that assumes slow retrapping.
The optical properties of TlGaSeS layered single crystals have been investigated
by measuring the transmission and the reflection in the wavelength region
between 400 and 1100 nm. The optical indirect transitions with a band gap
energy of 2.27 eV and direct transitions with a band gap energy of 2.58 eV were
found by analyzing the absorption data at room temperature. The rate of change
v
of the indirect band gap with temperature was determined from the transmission
measurements in the temperature range of 10&ndash<br>300 K. The oscillator and the
dispersion energies, the oscillator strength, and the zero-frequency refractive
index were also reported. The parameters of monoclinic unit cell and the
chemical composition of TlGaSes crystals were found by X-ray powder
diffraction and energy dispersive spectroscopic analysis, respectively.
4
Goksen, Kadir. "Optical Properties Of Some Quaternary Thallium Chalcogenides." Phd thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12609442/index.pdf.
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Optical properties of Tl4In3GaSe8, Tl4InGa3Se8, Tl4In3GaS8, Tl2InGaS4 and Tl4InGa3S8 chain and layered crystals were studied by means of photoluminescence (PL) and transmission-reflection experiments. Several emission bands were observed in the PL spectra within the 475-800 nm wavelength region. The results of the temperature- and excitation intensity-dependent PL measurements in 15-300 K and 0.13×<br>10-3-110.34 W cm-2 ranges, respectively, suggested that the observed bands were originated from the recombination of electrons with the holes by realization of donor-acceptor or free-to-bound type transitions. Transmission-reflection measurements in the wavelength range of 400-1100 nm revealed the values of indirect and direct band gap energies of the crystals studied. By the temperature-dependent transmission measurements in 10-300 K range, the rates of change of the indirect band gap of the samples with temperature were found to be negative. The oscillator and dispersion energies, and zero-frequency refractive indices were determined by the analysis of the refractive index dispersion data using the Wemple&ndash<br>DiDomenico single-effective-oscillator model. Furthermore, the structural parameters of all crystals were defined by the analysis of X-ray powder diffraction data. The determination of the compositional parameters of the studied crystals was done by energy dispersive spectral analysis experiments.
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Isik, Mehmet. "Thermally Stimulated Current Study Of Traps Distribution In Beta-tlins2 Layered Crystals." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12609667/index.pdf.
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Trapping centres in as-grown TlInS2 layered single crystals have been studied by using a thermally stimulated current (TSC) technique. TSC measurements have been performed in the temperature range of 10-300 K with various heating rates. Experimental evidence has been found for the presence of five trapping centres with activation energies 12, 14, 400, 570 and 650 meV. Their capture cross-sections and concentrations were also determined. It is concluded that in these centres retrapping is negligible as confirmed by the good agreement between the experimental results and the theoretical predictions of the model that assumes slow retrapping. An exponential distribution of traps was revealed from the analysis of the TSC data obtained at different light excitation temperatures.
The transmission and reflection spectra of TlInS2 crystals were measured over the spectral region of 400-1100 nm to determine the absorption coefficient and refractive index. The analysis of the room temperature absorption data revealed the coexistence of the indirect and direct transitions. The absorption edge was observed to shift toward the lower energy values as temperature increases from 10 to 300 K. The oscillator and the dispersion energies, and the zero-frequency refractive index were also reported. Furthermore, the chemical composition of TlInS2 crystals was determined from energy dispersive spectroscopic analysis. The parameters of monoclinic unit cell were found by studying the x-ray powder diffraction.
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Fairbrother, P. J. "Thermal diffuse scattering in energy-dispersive x-ray spectroscopy." Thesis, University of Exeter, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.232967.
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Geraki, Kalotina. "Differentiating normal and diseased breast tissue using X-ray fluorescence and energy dispersive X-ray diffraction." Thesis, City University London, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.274458.
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Kasemodel, Carlos A. "Quantitative energy dispersive x-ray spectrometry using an Emispec Vision system." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1999. http://handle.dtic.mil/100.2/ADA374498.
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Thesis (M.S. in Applied Physics) Naval Postgraduate School, December 1999.<br>"December 1999". Thesis advisor(s): Alan G. Fox, James Luscombe. Includes bibliographical references (p. 69-70). Also available online.
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Canli, Sedat. "Thickness Analysis Of Thin Films By Energy Dispersive X-ray Spectroscopy." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612822/index.pdf.
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EDS is a tool for quantitative and qualitative analysis of the materials. In electron microscopy, the energy of the electrons determines the depth of the region where the X-rays come from. By varying the energy of the electrons, the depth of the region where the X-rays come from can be changed. If a thin film is used as a specimen, different quantitative ratios of the elements for different electron energies can be obtained. Unique thickness of a specific film on a specific substrate gives unique energy-ratio diagram so the thickness of a thin film can be calculated by analyzing the fingerprints of the energy-ratio diagram of the EDS data obtained from the film.
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Slater, Thomas Jack Alfred. "Three dimensional chemical analysis of nanoparticles using energy dispersive X-ray spectroscopy." Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/three-dimensional-chemical-analysis-of-nanoparticles-using-energy-dispersive-xray-spectroscopy(3eb607a2-eb03-4d45-b9eb-71b0ca45c2db).html.
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The aim of this thesis is to investigate the methodology of three dimensional chemical imaging of nanoparticles through the use of scanning transmission electron microscope (STEM) – energy dispersive X-ray (EDX) spectroscopy. In this thesis, an absorption correction factor is derived for spherical nanoparticles that can correct X-ray absorption effects. Quantification of EDX spectra of nanoparticles usually neglects X-ray absorption within the nanoparticle but may lead to erroneous results, thus an absorption correction is important for accurate compositional quantification. The absorption correction presented is verified through comparison with experimental data of Au X-ray peaks in spherical Au nanoparticles and is found to agree excellently. This absorption correction allows accurate compositional quantification of large ( > 100 nm) particles with STEM-EDX.Three dimensional chemical mapping is achievable through the use of EDX spectroscopy with electron tomography. Here, the methodology of STEM-EDX tomography is fully explored, with a focus on how to avoid artefacts introduced through detector shadowing and low counts per pixel. A varied-time acquisition scheme is proposed to correct for detector shadowing that is shown to provide a more constant intensity over a series of projections, allowing a higher fidelity reconstruction. The STEM-EDX tomography methodology presented is applied to the study of AgAu nanoparticles synthesized by the galvanic replacement reaction. The elemental distribution as a function of the composition of the as-synthesized nanoparticles is characterised and a reversal in the element segregated to the surface of the nanoparticles is found. The composition at which the reversal takes place is shown to correlate with a peak in the catalytic yield of a three component coupling reaction. It is hypothesized that a continuous Au surface results in the optimum catalytic conditions for the reaction studied, which guides the use of galvanically prepared AgAu nanoparticles as catalysts.
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Kumari, Maini S. M. "Development of a breast tissue diffraction analysis system using energy dispersive X-ray diffraction." Thesis, University College London (University of London), 2012. http://discovery.ucl.ac.uk/1370578/.
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Research groups have shown that diffraction techniques could be applied for characterising materials. In particular, Energy Dispersive X-ray Diffraction (EDXRD) technique has been successfully used in characterising materials such as plastics, drugs and biological tissues. The size of breast tissues used for characterisation so far has been small, in the range of mm. In order to exploit the fullness of the EDXRD technique in characterising breast tissues and hence enable early and precise breast tumour detection, the presented research work takes the existing research work a step forward by developing a breast tissue diffraction analysis system wherein breast-sized tissue-equivalent materials have been studied for tumour detection and an optimised EDXRD system for breast tissue analysis has been presented. For the development of this breast tissue analysis diffraction system, a ray-tracing model of the EDXRD system has been developed. The model has been used to predict diffraction spectra. These model predictions have been further used to optimize system parameters for an EDXRD system so it could be used for breastsized samples. Materials like plastics, pharmaceutical drugs and tissues have been characterised on this optimized system. The diffraction spectra collected have been used to build a diffraction spectrum database which has been further used to generate diffraction images for detection of tumour of size as small as 0.5 cm. Following this abstract, in the thesis, Chapter 1 introduces how X-rays interact with matter and what research groups have achieved so far in breast tissue diffraction. Ray-tracing model of EDXRD system forms Chapter 2 wherein the system parameters along with the corrections used in the model and model predictions have been presented. The characterisation of materials using optimized EDXRD system has been detailed in Chapter 3. Chapter 4 elaborates the generation of diffraction images. Chapter 5 presents the conclusions and suggests future work. The thesis ends with a list of references.
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Unuigbe, David Moweme. "Characterisation of silicon nanoparticles produced by mechanical attrition using scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray photoemission spectroscopy." Master's thesis, University of Cape Town, 2012. http://hdl.handle.net/11427/12105.
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Includes abstract.<br>Includes bibliographical references.<br>The establishment of printing technologies, using nanoparticle based inks, promises inexpensive manufacture of electronic devices. However, to produce working devices, nanoparticles have to meet requirements on size, shape, and composition. In the application of silicon nanoparticles in electronics, it is important that a network of interconnecting particles is formed through which charge transport can take place. Of further importance is that there is an absence of surface oxide in order to maintain a direct silicon-silicon connection within the network. In this work, cheap and scalable production of silicon nanoparticles is achieved efficiently with a top-down process of mechanical attrition by high energy milling.
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Menendez-Alonso, Elena. "Trace metal and speciation analysis using ion-exchange and energy dispersive X-ray fluorescence spectrometry." Thesis, University of Plymouth, 2000. http://hdl.handle.net/10026.1/896.
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Studies have been carried out on specific ion-exchange (Dowex 50W-X8 and Dowex 1-X8) and chelation (Chelex-100) resins, in order to determine their physical and chemical characteristics, to understand and explain their limits of function and to optimise their use as substrates in trace metal and speciation measurement by EDXRF. Structural information was obtained by scanning electron microscopy and x-ray microanalysis showing a homogeneous distribution of functional groups and retained ions on both sectioned and whole resins. Particle size experiments performed on Dowex 50W-X8 (38 - 840 µm) showed that this parameter has no effect on the relationship between intensity of fluorescence and concentration or mass of resin. Inter-element effects were not observed in the analysis of multielemental specimens prepared on ion-exchange / chelation media by EDXRF. This indicates that the proposed method has a significant advantage when compared with other methodologies. A theoretical ‘model’, based on the formation of thin films on the surface of the resin beads, has been proposed in order to link and explain the effects observed in these experiments. The use of a batch retention system has shown distinct advantages over using columns in terms of linearity, accuracy, precision, rapidity and simplicity. Parameters such as pH and ionic strength of the solution, concentration of competing ions and volume of the sample have been proven to be critical. The maximum retention capacity has been determined as 3.2, 1.1 and 0.67 mEq/g for Dowex 50W-X8, Dowex 1-X8 and Chelex-100 respectively. The optimum mass of resin for XRF analysis was found to be 0.5 g, for all resins tested. The linear range covered 4 to 5 orders of magnitude. These findings show the potential of the investigated media to overcome instrumental and sample limitations. Based on the physico-chemical information found, methodologies for three different applications of the resins to EDXRF determinations have been developed and their analytical possibilities explored. The multi-elemental determination of metals in sewage sludge digests was achieved by retaining the metals on Dowex 50W-X8 at pH 2 and Chelex-100 at pH 4. Chelex-100 allows quantitative recoveries for Cu and Zn. A wider range of elements was determined on Dowex 50W-X8, although with poorer recoveries (60 - 90%). The limits of detection were 10 - 21 µg when Dowex 50W-X8 was used and 8 - 49 µg for Chelex-100. The method was validated by the analysis of a certified material. The determination of Kβ/Kα intensity ratios for Cr and Mn species and its potential as a tool for direct elemental speciation has also been studied. A difference in Kβ/Kα between the oxidation states of the analytes was only observed during the analysis of solutions of the metal species by EDXRF at the 98% level of confidence. Finally, the speciation and preconcentration of Cr(III) and Cr(VI) in waters has been performed by retention on Dowex 50W-X8 and Dowex 1-X8 followed by EDXRF determination. Efficient recoveries and preconcentration factors of up to 500 were achieved, leading to limits of detection of 30 µg/L for Cr(VI) and 40 µg/L for Cr(III). This method is simple, fast and inexpensive, allowing quantitative recoveries in the speciation of chromium in waste waters.
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PEÑAFIEL, MARLIN JEANNETTE PEDROZO. "DETERMINATION OF SILICON AND ALUMINUM IN CRUDE OIL USING ENERGY DISPERSIVE X-RAY FLUORESCENCE SPECTROMETRY." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2016. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=33880@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO<br>A determinação de diferentes níveis de silício e alumínio em petróleo é importante porque pequenas quantidades destes elementos podem produzir efeitos adversos nas refinarias devido à corrosão de equipamento ou afetar a qualidade dos produtos refinados. A espectrometria de fluorescência de raios-X por dispersão de energia (EDXRF) foi utilizada para desenvolver um método para a determinação de Si e Al em petróleo, onde estes elementos se encontram principalmente sob a forma de partículas sólidas de aluminossilicatos dispersas na amostra. Uma vez que os analitos não puderam ser determinados sem interferência diretamente no óleo, a fusão das amostras de petróleo foi realizada utilizando tetraborato de lítio. Em seguida, as amostras fundidas foram colocadas no centro de papéis de filtro de 10 mm de diâmetro, que foi colocado entre duas folhas de filme de polipropileno, para então ser fixado à cubeta para as medições no instrumento. A quantificação foi feita por meio de curvas analíticas no intervalo de concentração de 0 a 40 mg kg(-1) (para ambos os elementos) no material fundido final. O método desenvolvido, não sofreu interferência matriz uma vez que as amostras foram completamente decompostas e, posteriormente secas no substrato. Os resultados para os elementos foram estatisticamente comparáveis com os obtidos por espectrometria de absorção atômica com chama (FAAS). Além disso, os resultados concordaram com os obtidos nas amostras de programas de proficiência da ASTM. Amostras reais de petróleo, fornecidas pela Petrobras, também foram analisadas. As recuperações alcançadas se encontram entre 71 e 100 por cento para as diferentes amostras, o qual pode ser considerado satisfatório devido à dificuldade em se determinar esses elementos. Os limites de quantificação (10 vezes o desvio-padrão, n=10) encontrados para o Si e Al no petróleo foram de 0,7 e 1,1 mg kg(-1), respectivamente, mostrando o potencial do método proposto para a determinação de amostras com valores mais elevados destes elementos.<br>It is important to determine silicon and aluminum at different levels in crude oils because of trace amounts of these elements may produce adverse effects in oil refining either by causing corrosion or by contaminating and affecting the quality of the refined products. Energy dispersive X-ray fluorescence spectrometry (EDXRF) was used to enable a reliable method for determination of Si and Al in crude oil, where these elements are found mainly in the form of solid aluminosilicate particles dispersed in the sample. Since the analytes could not be determined directly in the oil without interference, the fusing the crude oil samples was made using lithium tetraborate. Then, the fused samples were placed in the center of 10 mm diameter filter paper that were sandwiched between two polypropylene film foils and attached to the instrument cell for measurements. Quantification was made by using analytical curves in the concentration range from 0 to 40 mg kg (-1) (for both elements) in the final fused material. The method
developed did not suffer from matrix effect once the sample matrix was completely decomposed and the sample solution dried in the substrate before measurements. The results for the elements were statistically comparable to the ones obtained by flame atomic absorption spectrometry (FAAS). In addition, for proficiency test samples, the results were in accordance to the ones reported by ASTM proficiency
programs. Real samples of oil provided by Petrobras Company also were analyzed. Recoveries were achieved between 71 and 100 percent for different samples, which can be considerable satisfactory because of the difficulty in determine those elements. The limits of quantification (10 times the standard deviation. N = 10) found for silicon and aluminum in the oil were of 0.7 and 1.1 mg kg (-1), respectively, showing the potential of the proposed method to screen for samples with higher amounts of these elements.
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Cook, Emily Jane. "Analysis of energy dispersive x-ray diffraction profiles for material identification, imaging and system control." Thesis, University College London (University of London), 2008. http://discovery.ucl.ac.uk/1446057/.
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This thesis presents the analysis of low angle X-ray scatter measurements taken with an energy dispersive system for substance identification, imaging and system control. Diffraction measurements were made on illicit drugs, which have pseudo- crystalline structures and thus produce diffraction patterns comprising a se ries of sharp peaks. Though the diffraction profiles of each drug are visually characteristic, automated detection systems require a substance identification algorithm, and multivariate analysis was selected as suitable. The software was trained with measured diffraction data from 60 samples covering 7 illicit drugs and 5 common cutting agents, collected with a range of statistical qual ities and used to predict the content of 7 unknown samples. In all cases the constituents were identified correctly and the contents predicted to within 15%. Soft tissues exhibit broad peaks in their diffraction patterns. Diffraction data were collected from formalin fixed breast tissue samples and used to gen erate images. Maximum contrast between healthy and suspicious regions was achieved using momentum transfer windows 1.04-1.10 and 1.84-1.90 nm_1. The resulting images had an average contrast of 24.6% and 38.9% compared to the corresponding transmission X-ray images (18.3%). The data was used to simulate the feedback for an adaptive imaging system and the ratio of the aforementioned momentum transfer regions found to be an excellent pa rameter. Investigation into the effects of formalin fixation on human breast tissue and animal tissue equivalents indicated that fixation in standard 10% buffered formalin does not alter the diffraction profiles of tissue in the mo mentum transfer regions examined, though 100% unbuffered formalin affects the profile of porcine muscle tissue (a substitute for glandular and tumourous tissue), though fat is unaffected.
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West, Steven. "Geochemical and palynological signals for palaeoenvironmental change in south west England." Thesis, University of Plymouth, 1997. http://hdl.handle.net/10026.1/2156.
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This thesis evaluates the utility of a geochemical technique for the investigation of palaeoenvironmental change in south west England. The method, EDMA (Energy Dispersive X-ray Micro Analysis), is a rapid, non-destructive analysis tool, capable of detecting a large range of geochemical elements. This research examines the most appropriate method of sample preparation for organic soils and peats, and investigates the reliability of results gained from EDMA with respect to conventional bulk geochemical techniques. A detailed study focused on a range of different sedimentary sites in south west England where a variety of palaeoenvironmental changes were thought to occur. Pollen analysis was undertaken on the same sedimentary material, and provided complementary information on the nature and scale of vegetation change through time. Sediments from a coastal valley mire near North Sands, Salcombe, revealed information relating to the processes of sea-level change in this part of south Devon and the subsequent autogenic processes as the sediment accumulated through time. A range of sites were located on the granitic upland of Dartmoor. A raised bog, Tor Royal, provided data relating to the changing nature of the central upland landscape from late Mesolithic times to the present day. Two soligenous sites, Upper Merrivale and Piles Copse, sought to investigate the activities of postulated anthropogenic activity at a much smaller spatial scale, with particular interest placed upon the evidence for deforestation activity and the utilisation of the local mineral resources. The last site, Crift Down, a lowland spring fed valley mire utilised geochemical and palynological fluxes within the peat to investigate processes and activities associated with archaeological evidence for Medieval tinworking in this area of Cornwall. The results from the EDMA investigations, and comparable studies using other geochemical methods including EMMA, AAS and flame photometry, suggest the technique to have greatest applicability as a first stage tool in the analysis of general activities of past environmental change. The technique was found to yield reliable results for the major elements (Si, Al, 5, Fe, Ca, K, Na and Mg), but is generally incapable of providing useful data on heavy metal elements. The data from south west England suggest the method to reflect activity at a range of different scales, and as part of a structured programme of analysis may contribute information to allow a more holistic environmental reconstruction to be made.
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Salvi, Anna Maria. "The relationship between atomic number and the intensity of the energy loss structure of the photoelectron spectrum." Thesis, University of Surrey, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.320908.
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Hansson, Conny. "Development of a novel colour X-ray coherent scatter imaging system." Thesis, University of Manchester, 2010. https://www.research.manchester.ac.uk/portal/en/theses/development-of-a-novel-colour-xray-coherent-scatter-imaging-system(b8d3f9b0-60ea-48d1-9175-b8abc242a222).html.
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The field of X-ray imaging and X-ray diffraction have been combined in a new technique called Tomographic Energy Dispersive Diffraction Imaging (TEDDI). This diffraction imaging technique allows 3D sample images to be obtained, non-destructively, where each imaged point contains the atomic structural information associated with its diffraction pattern. The main drawback of the TEDDI technique is the long collection times needed to produce the images. In order to overcome this obstacle the rapid TEDDI (rTEDDI) system has been developed at the University of Manchester's Material Science Centre. The research and development of rTEDDI has been the focus of this PhD thesis. A proof of concept for the rTEDDI imaging technique was obtained using thin samples on station 7.6 SRS Daresbury. In this case a first generation array collimator was used in conjunction with an energy resolving Si pixelated detector. Structural information such as lattice parameters, crystal system and phase identiffcation were obtained for metal, polymer and deer antler bone samples. The use of high Z semiconductor detector material was investigated in order to increase the potential of TEDDI for larger and more dense samples. To enable penetration of larger samples high energy X-rays needed to be utilized. In order to detect these higher energies with a good efficiency the detector media was changed from Si to CdZnTe (CZT).The second generation rTEDDI, using CZT as the detection media, was intended to be used under high flux/high energy synchrotron radiation conditions. Testing of the system under these conditions on station 16.3 SRS Daresbury showed an inability to produce diffraction imaging. An in depth investigation into detector and collimator array performance showed a two fold cause. The ERD2004 detector was unable to handle the high countrates experienced during high flux/high energy synchrotron radiation conditions. The MK1.2 collimator array was found to become partially transparent to X-ray energies around the absorption edge of W resulting in the swamping of the diffraction signal under high flux/high energy synchrotron radiation conditions. A new detector Application Specific Integrated Circuit (ASIC) design, developed by the detector division and the Rutherford Appleton Laboratory, and Data Aquisition (DAQ) system, developed by Aspect Systems, as well as a number of new collimator array designs were developed and tested. Testing of the new collimator array structures have shown positive results and the new HEXITECdetector which was designed to be able to handle high countrates, have shown an unprecedented inter pixel uniformity and energy resolution which have been attributed to the ASIC performance and the use of better quality CZT material.
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Gharehbaghi, Ali. "Precipitation Study in a High Temperature Austenitic Stainless Steel using Low Voltage Energy Dispersive X-ray Spectroscopy." Thesis, KTH, Materialens processteknologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-103492.
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Precipitation of second phase particles is a key factor dominating the mechanical properties of high temperature alloys. In order to control and optimize the precipitation effect it is of great importance to study the role of alloying elements in the formation and stability of precipitates. As a favored family of corrosion and creep resistant austenitic stainless steels the 20Cr-25Ni alloy was modified by addition of copper, molybdenum, nitrogen, niobium and vanadium. A set of alloys with similar matrix but varying contents of niobium, vanadium and nitrogen were prepared. Sample preparation process included melting, hot forging, solution annealing and finally aging for 500 h at 700, 800 and 850 ºC.Light optical and scanning electron microscopy revealed micron-scale precipitates on grain and twin boundaries as well as sub-micron intragranular precipitates in all samples. Characterization of precipitates was carried out by means of energy dispersive X-ray spectroscopy (EDS). Among micron-scale precipitates M23C6 carbide was the dominant phase at 700 ºC aging temperature; whereas silicon-rich eta phase (M5SiC) was the main precipitate in samples aged at 800 and 850 ºC. A few sigma phase particles were found in one of the niobium containing samples aged at 700 and 800 ºC. Sub-micron intragranular precipitates were analyzed using low voltage EDS. The spatial resolution of EDS microanalysis at 5 kV accelerating voltage was estimated as almost 100 nm which was at least eight times better than that using the ordinary 20 kV voltage. Also, low voltage EDS revealed the presence of light elements (carbon, nitrogen and boron) in the composition of sub-micron particles thanks to the less matrix effect in absorption of low energy X-rays of light elements. In samples aged at 700 ºC niobium-rich and vanadium-rich carbonitrides were found as the dominant precipitates; whereas they contained much less carbon in samples aged at 800 ºC and mostly became carbon-free nitrides with well-defined cuboidal shapes at 850 ºC aging temperature. This showed that niobium/vanadium-rich nitride phases are stable precipitates at aging temperatures above 700 ºC.The drawbacks of low voltage EDS were indicated as high detection limit (no detection of low- content elements), poor accuracy of quantitative analysis and high sensitivity to surface contamination. Some possible ways to improve the accuracy of low voltage EDS, e.g. longer acquisition time were examined and some other suggestions are proposed for future works.
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Allday, Allan William. "Detection capabilities of energy dispersive X-ray diffraction with respect to in-vitro trabecular bone mineral loss." Thesis, City University London, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.407536.
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Van, Loggerenberg Daniël Elhardus. "Important trace element concentrations in ovine liver as determined by energy dispersive handheld X-ray fluorescence spectrometry." Diss., University of Pretoria, 2016. http://hdl.handle.net/2263/65518.
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Trace elements are involved in a variety of biochemical processes essential to life and are required in minute amounts. There are no data available on the use of handheld X-ray fluorescence (XRF) spectrometry to determine concentrations of important trace elements in ovine livers. The aim of this study was to ascertain if the handheld X-ray fluorescence spectrometer will provide reliable concentrations of certain essential trace elements in the livers of sheep. Sheep livers (n=30) were obtained from abattoirs. Wet liver samples taken from 30 liver specimens were blended until homogeneity was achieved. An aliquot of the homogenised liver samples were oven dried at 50°C until a constant mass and were then pulverised using a mortar and pestle to obtain a fine powder. In addition, homogenised liver samples (n = 30) were also submitted for dry ashing. All the prepared liver samples (i.e. wet blended, oven dried and dry ashed) were then analysed using a handheld X-ray fluorescence spectrometer to determine concentrations of copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), selenium (Se) and zinc (Zn). A reference laboratory analysed the same liver samples using ICP-MS to determine the concentrations of the above mentioned trace elements (control). The means (mg/kg) of the ICP-MS results on a dry matter basis were: Cu (505), Fe (351), Mn (12.3), Mo (3.8), Se (1.8) and Zn (168). The means (mg/kg) of the XRF oven-dried results were: Cu (502), Fe (289), Mn (11.7), Mo (1.6) and Zn (141.9). Selenium could not be detected in oven-dried samples when using the XRF. The intra-sample coefficients of variation were similar between ICP-MS and XRF for oven dried samples for Cu, Fe and Zn and are within the same order of magnitude for all elements in dry ashed samples when comparing ICP-MS to XRF. However, the intra-sample coefficients of variation for Mn and Mo were approximately an order of magnitude larger using XRF. Although the precision for Se appears to be good when using XRF on dry ashed samples, Se was only detected in a few samples, so this value is not representative of the overall precision of XRF using the dry ashed preparation procedure for Se determination. Selenium was not detectable using XRF on wet blended and oven dried samples. The intra-sample coefficient of variation for Se was relatively high using ICP-MS, suggesting that even the current ‘gold standard’ in detecting trace-elements may be imprecise in measuring Se. Overall, this suggests that the precision of sampling using XRF is relatively good for only Cu, Fe and Zn and relatively poor for Mn and Mo. Furthermore, XRF cannot be reliably used for measuring Se. Bayesian correlation were used to determine the best correlation between XRF and ICP-MS data. Bayesian correlation results are summarised by the median sample Pearson product-moment correlation coefficient (r), the 95% lower (LHPDI) and upper (UHPDI) highest posterior density intervals, the square of the sample correlation coefficient (r2), and the probability that the correlation coefficient is positive. Overall, the oven-dried preparation procedure for XRF appeared to provide the best correlation with the ICP-MS data. For Cu and Zn these correlations were strong and the XRF method may represent a suitable substitute for ICP-MS. For Mn and Fe the correlations were moderately strong and the XRF method may be suitable depending upon the intended application. For Mo the correlation was moderate and XRF cannot be recommended. For Se no XRF method was suitable. The advantage of handheld X-ray spectrometry is that the turnaround time of samples is reduced a great deal. Instead of submitting samples to a laboratory and waiting for results, samples can be analysed more rapidly with the use of a handheld X-ray fluorescence spectrometer.<br>Dissertation (MSc)--University of Pretoria, 2016.<br>Paraclinical Sciences<br>MSc<br>Unrestricted
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Aquilanti, Giuliana. "Challenges for energy dispersive X-ray absorption spectroscopy at the ESRF : microsecond time resolution and Megabar pressures." Université Joseph Fourier (Grenoble), 2002. http://www.theses.fr/2002GRE10195.
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La Thèse s'articule en deux parties distinctes, autour de l'exploitation des caractéristiques exceptionnelles d'une ligne de lumière d'absorption X en géométrie dispersive dans un synchrotron de troisième génération. La première partie décrit la possibilité d'effectuer des études de spectroscopie d'absorption X résolues en temps avec une résolution temporelle de l'ordre de la microseconde. L'étude de la structure de l'état excité du composé Pt2(P20sH2)44- a été choisi pour mettre au point cette technique. Dans la deuxième partie, l'adéquation entre les possibilités offertes par une ligne d'absorption X en dispersion d'énergie et les expériences à très hautes pressions obtenues dans les cellules à enclumes de diamants est mise en évidence. Outre les développements instrumentaux, cette dernière technique est illustrée par une étude combinée par diffraction et par absorption des rayon X du composé InAs sous pression<br>This Thesis concerns the development of two different applications of energy-dispersive Xray absorption spectroscopy at the ESRF: time-resolved (TR) studies pu shed to the microsecond time resolution and high-pressure (HP) studies at the limit of the Megabar pressures. The work has been developed in two distinct parts, and the underlying theme has been the exploitation of the capabilities of an X-ray absorption spectrometer in dispersive geometry on a third generation synchrotron source. For TR studies, the study of the triplet excited state following a laser excitation of Ph(P20sH2)44- has been chosen to push the technique to the us time resolution. In the HP part, the suitability of the energy dispersive Xray absorption spectrometer for HP studies using diamond anvils cell is stressed. Sorne technical developments carried out on beamline ID24 are discussed. Finally, the most extensive scientific part concerns a combined X-ray absorption and diffraction study of InAs under pressure
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Palma, Joseph John. "X-ray Diffraction Studies of Amorphous Materials." Diss., Temple University Libraries, 2013. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/231213.
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Physics<br>Ph.D.<br>This thesis presents a study on two types of X-ray diffraction methodologies applied to the characterization of amorphous materials. The purpose of this study was to assess the feasibility of measuring the diffractive spectrum of amorphous materials by Energy-Dispersive X-ray Diffraction (EDXRD) utilizing Cadmium Zinc Telluride detectors. The total scattering intensity (coherent plus incoherent scatter) spectra precisely measured by high-energy Wide-Angle X-ray Scattering (WAXS) were compared to the EDXRD spectra to determine the level of agreement between the two techniques. The EDXRD spectra were constructed by applying a spectra fusing technique which combined the EDXRD spectra collected at different scattering angles rendering a continuous total scattering spectrum. The spectra fusing technique extended the momentum transfer range of the observed scattered spectrum beyond the limitations of the X-ray source and CZT detection efficiencies. Agreement between the WAXS and fused EDXRD spectra was achieved. In addition, this thesis presents the atomic pair correlation functions and coordination numbers of the first coordination shell for four hydrogen peroxide solutions of varying mass concentrations using Empirical Potential Structural Refinement (EPSR). The results are compared to the state-of-the art ad initio quantum mechanical charge field molecular dynamics (QMCF MD) model of the hydrogen peroxide in solution to support the model's predictions on why hydrogen peroxide is stable in water. The EPSR results using the coherent scattering intensity calculated from the WAXS data set predicts a hydration shell of 6.4 molecules of water surrounding hydrogen peroxide. The results also indicate that hydrogen peroxide is more likely to behave as a proton donor than acceptor. These findings are in agreement with QMCF MD model of aqueous hydrogen peroxide.<br>Temple University--Theses
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Dabah, Eitan [Verfasser], and Thomas [Akademischer Betreuer] Böllinhaus. "Hydrogen interaction with supermartensitic stainless steel studied by energy dispersive X-ray diffraction / Eitan Dabah. Betreuer: Thomas Böllinhaus." Magdeburg : Universitätsbibliothek, 2015. http://d-nb.info/1076589898/34.
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Alkhateeb, Shyma Mohammed Fouad. "Development of a system for energy dispersive X-ray diffraction computed tomography of breast tissue samples and phantoms." Thesis, University of Surrey, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.616891.
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This work encompasses the study of energy dispersive X-ray diffraction CT (EDXRDCT) system to be installed outside breast tissue biopsy subtraction operation theatre. The system was tested using different materials that simulate breast tissue diffraction pattern contrast and shape compactness. The system spatial resolution was assessed to detect the smallest possible details in each position. The system detection of detail shapes was calculated using compactness parameter. Initially the EDXRDCT system was used with a pinhole CdTe detector to radiate samples of raw materials and different combinations of materials were counted to simulate the contrast between breast tissue at 1.1 nm- i and 1.6 nm- i . The system was then tested using cylindrical samples of two materials with different details sizes (2 mm, 1 mm and O.5mm) that simulate the contrast between breast tissues. Profiles of the EDXRDCT images were plotted and found that details until 1 mm of size can be detected. Some samples of different shapes and materials that simulate breast tissue was scanned using the EDXRDCT system with HEXITEC detector. Scanned parameters were optimised for the beast compactness results that give close values to MicroCT findings. Furthermore a waxed real tissue of liver was scanned to prove the feasibility of scanning waxed tissue instead of fresh ones. The compactness and diffraction of sample details was measured. Finally, a phantom that simulates breast tissue contrast and shapes was designed to test the EDXRDCT system with HEXITEC detector. The system was capable to show details shape and give close compactness values to Micro CT results in 2.5 hours scanning time.
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Demers, Hendrix. "Two facets of the x-ray microanalysis at low voltage: the secondary fluorescence x-rays emission and the microcalorimeter energy-dispersive spectrometer." Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=21993.
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The best spatial resolution, for a microanalysis with a scanning electron microscope (SEM), is achieved by using a low voltage electron beam. But the x-ray microanalysis was developed for high electron beam energy (greater than 10 keV). Also, the specimen will often contain light and medium elements and the analyst will have to use a mixture of K, L, and sometime M x-ray peaks for the x-ray microanalysis. With a mixture of family lines, it will be common to have secondary fluorescence x-rays emission by K-L and L-K interactions. The accuracy of the fluorescence correction models presently used by the analyst are not well known for these interactions. This work shows that the modified secondary fluorescence x-rays emission correction models can improve the accuracy of the microanalysis for K-L and L-K interactions. The general equation derived in this work allows the identification of three factors which influence the secondary fluorescence x-rays emission. The fluorescence production factor can be used to predict the importance of the secondary fluorescence x-rays emission. A large value of the fluorescence production factor indicates that a fluorescence correction is needed. Another disadvantage of using a low voltage is that there are more frequent occurrences of x-ray peaks overlap. A new microanalysis instruments that combines the high-spatial resolution and high-energy resolution for x-ray detection is needed. The microcalorimeter energy-dispersive spectrometer (uEDS) should improve the low voltage microanalysis, but the maturity of this technology has to be evaluated first. One of the first commercial uEDS for x-ray microanalysis in a SEM is studied and analyzed in this work. This commercial uEDS has an excellent energy resolution (15 eV) and can detect x-rays of low energy. This x-ray detector can be used as a high-spatial resolution and high-energy resolution microanalysis instrument. There are still hurdles that this technology must overcome before i<br>Pour la microanalyse par rayons X avec un microscope électronique à balayage (MEB), la meilleure résolution spatiale est obtenue à bas voltage. Cependant, la microanalyse par rayons X a été développée pour des grandes énergies du faisceau d'électrons (plus grandes que 10 keV). De plus, les échantillons analysés contiennent souvent des éléments légers et moyens. L'analyste va devoir utiliser un mélange de pics de rayons X K, L et parfois M pour la microanalyse par rayons X. Avec un aussi grand nombre de pics, l'émission de fluorescence secondaire de rayons X par des interactions K-L et L-K est inévitable. La précision des modèles de correction de la fluorescence utilisés présentement n'est pas bien quantifiée pour ces types d'interactions. Les modifications apportées, dans le cadre de ce travail, aux modèles de correction de la fluorescence améliorent la précision des résultats de la microanalyse pour les interactions K-L et L-K. L'équation générale dérivée dans ce travail permet l'identification de trois facteurs qui influencent l'émission de fluorescence secondaire de rayons X. Le facteur de production de fluorescence est utilisé pour prédire l'importance de l'émission de fluorescence de rayons X. Une grande valeur de ce facteur indique que la correction de fluorescence est nécessaire. Un autre désavantage d'utiliser une basse tension est le chevauchement des pics de rayons X qui se produit plus fréquemment. Un nouvel instrument de microanalyse qui combine une grande résolution spatiale et une grande résolution en énergie pour la détection des rayons X est nécessaire. Un spectromètre microcalorimétrique à dispersion d'énergie des rayons X (uEDS) devrait améliorer la microanalyse à basse tension, mais la maturité de cette technologie doit être évaluée. L'un des premiers spectromètre uEDS commercial pour la microanalyse par rayons X dans un MEB est étudié et analysé dans ce travail. Cet uEDS commercial$
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Manohar, Nivedh Harshan. "Effect of source x-ray energy spectra on the detection of fluorescence photons from gold nanoparticles." Thesis, Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/45970.
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X-ray fluorescence is a well-understood phenomenon in which irradiation of certain materials, such as gold, with x-rays causes the emission of secondary x-rays with characteristic energies. By performing computed tomography using these fluorescence x-rays, the material of interest can be imaged inside an object. Our research group has already demonstrated that x-ray fluorescence computed tomography (XFCT) imaging using a typical 110 kVp microfocus x-ray tube is feasible for a small animal-sized object containing a distribution of a solution of low concentration gold nanoparticles.
The primary goal of this thesis work was to study the effect of source x-ray energy spectra on gold fluorescence detection using the XFCT system. A computational approach using the Monte Carlo method was used. First, a computational model was created using the Monte Carlo N-Particle (MCNP) transport code based on the experimental setup of the pre-existing XFCT system. Simulations were run to verify the validity of the MCNP model as an accurate representation of the actual system by means of comparison with experimentally-obtained data. Finally, the model was used for further purely computational work.
In the MCNP model, the source spectrum was changed to reflect several theoretical and experimentally obtained options. The effect of these changes on gold fluorescence production was documented and quantified using the signal-to-background ratio and other qualitative measures.
The results from this work provided clues on how to improve the detection of fluorescence photons from gold nanoparticle-loaded objects using the XFCT system. This will benefit future research on the development of the XFCT system in the context of making it more feasible for gold nanoparticle-based preclinical molecular imaging applications.
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Kozul, Natasha. "Accurate species concentrations from x-ray attenuation at single and multiple energies using energy dispersive detectors and mathematical modelling." Thesis, Queen Mary, University of London, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.300750.
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Larsson, Ylva. "Establishing low-energy x-ray fields and determining operational dose equivalent conversion coefficients." Thesis, Stockholm University, Medical Radiation Physics (together with KI), 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-8319.
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<p>Reference radiation fields for x-ray qualities are described by the International Organization of Standards (ISO). This study describes the procedure to establish nine different low energy X-ray qualities at the national metrology laboratory, Swedish Radiation Protection Authority, following the document ISO 4037. Measurements of tube voltage, half-value layer, mean energy and spectral resolution have been performed for qualities N-15, N-20, N-25, N-30, N-40, L-20, L-30, L-35 and L-55. Furthermore, dose equivalent conversion coefficients for operational quantities ambient dose equivalent, personal dose equivalent and directional dose equivalent have been calculated by folding the mono-energetic conversion factors with measured spectral distributions of the x-ray qualities. The spectral distributions were unfolded from pulse-height distributions to photon distributions using simulated data of the semi-conductor detector used for measurements, generated with the Monte Carlo code PENELOPE.</p>
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GENEROSI, Amanda. "Energy dispersive X-ray reflectometry studies of the morphological response of Metal-Phthalocyanine sensing films upon exposure to NO2 molecules." Doctoral thesis, La Sapienza, 2006. http://hdl.handle.net/11573/917308.
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中江, 保一. "X線分光における微小ピークの高感度検出法及び基礎原子過程に関する研究". 京都大学 (Kyoto University), 2012. http://hdl.handle.net/2433/157581.
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Kariapper, Mohamed Sirajudeen. "X-ray standing wave studies of surface adsorption structures." Thesis, University of Warwick, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.365232.
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CRUZ, ALEX RUBEN HUAMAN DE LA. "DETERMINATION OF IRON IN IRON ORE BY ENERGY DISPERSIVE X‐RAY FLUORESCENCE SPECTROMETRY: A COMPARATIVE STUDY OF METROLOGICAL PERFORMANCE AND ECONOMIC IMPACT." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2013. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=22183@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO<br>COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR<br>PROGRAMA DE SUPORTE À PÓS-GRADUAÇÃO DE INSTS. DE ENSINO<br>O ferro é extraído sob a forma de minério de ferro, sendo 99 por cento utilizado na
indústria siderúrgica. Os documentos normativos existentes indicam a
volumetria como à técnica analítica para quantificar o teor de ferro em minério
de ferro, com exceção da ISO 9516-1: 2003, que, recomenda a espectrometria de
fluorescência de raios-X por comprimento de onda (WDXRF). Na literatura são
descritos estudos utilizando a espectrometria de fluorescência de raios-X por
dispersão de energia (EDXRF) para quantificar ferro em minério de ferro, mas
em nenhuma destas publicações é caracterizada a confiabilidade metrológica e a
incerteza de medição, sendo outros aspectos importantes na seleção de um
método analítico o impacto económico e tempo de análise. No presente trabalho
realizou-se um estudo comparativo de impacto económico, tempo de análise e
desempenho metrológico na quantificação de ferro em minério de ferro por meio
da técnica de EDXRF, comparando-o com a espectrofotometria de absorção
molecular e volumetria (titulação com dicromato de potássio), abrangendo a
incerteza de medição e a avaliação de parâmetros de validação para EDXRF. A
análise volumétrica foi realizado baseado nas normas ANBT NBR 8577:2011 e
ASTM E246:2010. Na espectrofotometria de absorção molecular, adaptou-se o
método da ortofenantrolina descrito na norma ABNT NBR 13934:1997. Nas
outras técnicas precisam-se da abertura da amostra, na EDXRF, as amostras
foram preparadas na forma de pastilha (pó de minério prensado). Os métodos
avaliados apresentaram desempenhos metrológicos equivalentes, os melhores
indicadores de custo e tempo em longo prazo foram observados para o método
por EDXRF na quantificação do teor de ferro em minério.<br>After its extraction in the form of iron ore, 99 per cent of the iron is employed in
the steel industry. The normative documents existents recommend to volumetry
as the technical analytic for quantification of iron in iron ore, with the exception
of ISO 9516-1: 2003, which recommends the fluorescence spectrometry X-ray
wavelength (WDXRF). In literature, there are studies using energy dispersive Xray
fluorescence spectrometry (EDXRF) to quantify iron in iron ore, but none of
these is characterized by complete validation and measurement uncertainty.
Other aspects to be considered when selecting an analytical method are the
financial cost and the time for analysis. In this work it is carried out a
comparative study of financial cost, time analysis and metrological performance
on quantification of iron ore through the EDXRF technique, in comparison with
the results obtained by molecular absorption spectrophotometry and volumetry
(titration with potassium dichromate), including measurement uncertainty
evaluation and some parameter of validation for EDXRF. The molecular
absorption spectrophotometry measurements were performed by colorimetric
orthophenanthroline method. Unlike the other approaches that require sample
preparation with acid, for EDXRF measurements, samples were prepared in
tablet form (pressed iron ore powder). The evaluated methods presented
equivalent metrological performances on determining iron in ore, but the best
long-term outcome for cost was observed in the results obtained by EDXRF
method.
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Fagerland, Steffen Knut. "Investigation of Focused Ion Beam/Scanning Electron Microscope parameters for Slice and View and Energy Dispersive X-ray Spectroscopy of Embedded Brain Tissue." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for materialteknologi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-25765.
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This Thesis investigates the optimization of a Focused Ion Beam/Scanning Electron Microscope (FIB/SEM) Slice and View protocol of brain tissue. Using a Slice and View protocol in a Dualbeam instrument, the ion and electron beams are used in sequence to alternately mill and image the newly exposed surface of a predefined volume. This creates serial section images that may be used for 3D reconstruction. Research questions addressed include finding FIB parameters most beneficial for accurate milling of the tissue, use of different software strategies and image processing for 3D reconstruction of selected subsets enclosed within the volume sectioned, and the use of Energy Dispersive X-ray Spectroscopy for revealing the volume contents \emph{a priori} of the Slice and View. The reults showed that FIB parameters of $30kV$ and $0.9nA$ provided sufficient accuracy and consistency; that the DAB labeling protocol provided characteristics easily identifiable of the morphology of selected interneurons which were reconstructed, but was difficult to use in a generalized semi-automatic reconstruction protocol; and a model created to test EDX tracing did show potential for its use to increase protocol efficiency by narrowing down the regions of interest of the FIB block.
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Kuei, Chun-Fu. "Transmission electron microscopy study on the formation of SiNX interlayer during InAlN growth on Si (111) substrate." Thesis, Linköpings universitet, Tunnfilmsfysik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-125472.
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Ternary indium aluminum nitride (InXAl1-XN) semiconductor is an attractive material with a wide-range bandgap energy varied from ultraviolet (Eg(AlN): 6.2 eV) to near infrared (Eg(InN): 0.7 eV). With tuning composition, it can be widely used to many optoelectronic device applications. In this thesis, I have studied InXAl1-XN film deposited on Si (111) substrate using natural and isotopically enriched nitrogen as reactive gas by reactive magnetron sputter epitaxy (MSE). Four series of experiments were performed, which are I. InAlN presputtering, II. InAlN sputter deposition, III. InAlN direct deposition, and IV. InAlN direct deposition using isotopically enriched nitrogen. The samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDX). The θ-2θ XRD scan confirms that the designed composition x = 0.17 of InXAl1-XN film was obtained. TEM images shows that an amorphous interlayer with a thickness ranging from 1.2 nm to 1.5 nm was formed between Si substrate and InXAl1-XN film. However, high-resolution TEM shows that the interlayer actually contains partial crystalline structures. EDX line profile indicates that the chemical composition of the amorphous interlayer is silicon nitride (SiNX). By comparing d-spacing measurement of partial crystalline structures with EDX line profile, it reveals that partial SiNX crystal is formed in the interlayer. Nonetheless, the samples (IAD01, IAD02, IAD03, IAD04), grown without presputtering procedure, contain both crystalline SiNX and InXAl1-XN embedded in the amorphous interlayer. It means that SiNX and InXAl1-XN film can be directly grown on the substrate in the beginning of deposition. Moreover, the samples (IAD01, IAD03), quenched directly after deposition, have less crystalline structures in the interlayer then the samples (IAD02, IAD04), maintained at 800℃ for 20 min.
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Gul, Sheraz. "Synthesis, Optical and Structural Characterization, and Exciton Dynamics of Doped ZnSe Nanocrystals, and, Simultaneous X-ray Emission Spectroscopy of Two Elements Using Energy Dispersive Spectrometer." Thesis, University of California, Santa Cruz, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=3630692.
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<p> Doped semiconductor quantum dots (QDs) comprise an important subclass of nanomaterials in which a small quantity of impurity is added intentionally, adding another degree of freedom to alter their size-dependent physical and electronic properties. Intense, tunable, long lived and stable photoluminescence make them quintessential candidates for many opto-electronic applications including solid-state lighting, display devices and biomedical imaging. ZnSe QDs, which are blue-emitting fluorophores, were doped with Cu<sup>+1</sup> to redshift their photoluminescence (PL) to green region of the visible spectrum. These Cu-doped ZnSe QDs were then codoped with Al<sup>3+</sup>, Ga<sup> 3+</sup> and In<sup>3+</sup> to improve the PL quantum yield (QY) by eliminating the defect states originating from charge imbalance created by aliovalent doping. Codoping also resulted in further redshifting of the PL, covering most of the visible spectrum, making them potential candidates for use in solid-state lighting and as optical down converters in next generation light emitting diodes (LEDs). To better understand the optical properties of these materials, local structure around the luminescent centers was investigated by extended X-ray absorption fine structure (EXAFS). Cu was found to occupy a distorted tetrahedral site with the codopant residing in a substitutional Zn site. Based on the structural information obtained by EXAFS, density functional theory calculations (DFT) were performed to get a clear picture of the energy levels associated with the electronic transitions. Furthermore, the dynamics studies of the exciton and charge carriers were carried out to get deeper insight of the various photophysical processes involved. The fluorescence lifetime was increased approximately 10 times after doping. </p><p> The multielectron catalytic reactions often involve multimetallic clusters, where the reaction is controlled by the electronic and spin coupling between metals and ligands to facilitate charge transfer, bond formation/breaking, substrate binding, and release of products. A method was developed to detect X-ray emission signal from multiple elements simultaneously to probe the electronic structure and sequential chemistry that occurs between the elements. A wavelength dispersive spectrometer based on the von-Hamos geometry was used, that disperses Kβ emission signals of multiple elements onto an area detector, and enables an XES spectrum to be measured in a single-shot mode. This overcomes the scanning needs of the Rowland circle spectrometers, and the data is free from temporal and normalization errors, and therefore ideal to follow sequential chemistry at multiple sites. This method was applied to MnO<sub>x</sub> based electrocatalysts, and the effect of Ni addition was investigated. Electro-deposited Mn oxide catalyses oxygen-evolution reaction (OER) and oxygen-reduction reaction (ORR) at different electrochemical potentials under alkaline condition. Incorporation of Ni reduced the low valent Mn component resulting in higher average oxidation state of Mn in MnNiOx under ORR and OER conditions, when compared to MnO<sub> x</sub> under similar conditions. The reversibility of the electrocatalyst was also found to improve by the inclusion of Ni.</p>
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Parajuli, Prabin. "EXPERIMENTAL INVESTIGATION OF CORROSION OF COATED CAST IRON ROTORS IN THE AUTOMOTIVE INDUSTRY." OpenSIUC, 2020. https://opensiuc.lib.siu.edu/theses/2711.
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Electric and hybrid vehicles uses regenerative braking, where application of the brake triggers the electric motor to work as a generator to produce electricity, which in turn charges the battery. This results in much less use of the friction brake, changing the corrosion and wear behavior of the rotor surface. There is a need for research on this topic, since fully electric or hybrid vehicles are replacing combustion engines due to concerns about global warming and climate change. Here the corrosion behavior of coated cast iron vehicle rotors in 3.5wt% NaCl is studied. The corrosion study has been performed using electrochemical methods such as cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). All the coated samples were provided by Pure Forge Rotors. Based on the results from SEM and EDX, the coating is atomic forge proprietary coating, and the base material is gray cast iron. Our primary objective is to study the corrosion behavior of coated, non-coated and friction-tested samples. CV experiments indicate a shift in the corrosion potential and corrosion current density due to changes in the nature of the exposed surface. Cross-sectional SEM showed the thickness of the coating to be 16-23 µm. After friction testing, the friction layer created by rubbing the brake pad over the rotor plays a role in corrosion resistance, but this depends on the type of brake pad material (i.e. semi-metallic, non-asbestos organic and low metallic). Results showed that friction film that forms after testing against non-asbestos organic pads provides the highest corrosion resistance amongst the three brake pad materials.
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Yamane, H., T. Kawano, K. Tatsumi, Y. Fujimichi, and S. Muto. "Site occupancy determination of Eu/Y doped in Ca2SnO4 phosphor by electron channeling microanalysis." Elsevier, 2011. http://hdl.handle.net/2237/20827.
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Abuchi, Chukwuneke Sid. "Application of Energy Dispersive X-Ray Diffraction (EDXRD) in the detection of fat nodules in liver disease and plaques in the blood vessels of the heart." Thesis, University College London (University of London), 2018. http://discovery.ucl.ac.uk/10043618/.
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Fat deposits in tissue or organs are a major health problem. Assessment of fat nodules in the liver (particularly prior to a liver transplant) or plaques in coronary arteries are important investigations that are undertaken in hospitals throughout the world. Many of the current techniques for investigation, e.g., computed tomography coronary angiography (CTCA), lead to high radiation doses or carry significant risks (catheter angiography) and hence new, quantitative tests are required. This thesis looks at using localised X-ray diffraction measurements as an alternative approach to quantifying the fat content of blood vessels or liver tissue. Energy dispersive X-ray diffraction (EDXRD) has been used to study the diffraction profiles of specially designed tissue phantoms. Phantoms have been built to represent a fatty-liver and a diseased heart where the size of the fatty inclusion can be varied. Combinations of tissue equivalent materials and real tissues have been used in each phantom. Diffraction profiles have been measured on these phantoms for a range of fat inclusions. All measurements were made on a fixed geometry diffractometer using a nominal scattering angle of 60 , a High Purity Germanium (HPGe) detector system and a tungsten target X-ray source. The diffraction data has been subjected to different analysis procedures. The results on the phantoms have shown that the minimum detectable levels of fat inclusions are clinically relevant. These results have then been used to scale up the measured diffraction data to patient-sized objects. Although these estimates demonstrate that doses need to be increased they also indicate that useful clinical data could be obtained at acceptable dose levels.
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Ditto, Jeffrey. "Characterization of the Local Structure and Composition of Low Dimensional Heterostructures and Thin Films." Thesis, University of Oregon, 2016. http://hdl.handle.net/1794/20434.
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The observation of graphene’s extraordinary electrical properties has stirred great interest in two dimensional (2D) materials. The rapid pace of discovery for low dimensional materials with exciting properties continue with graphene allotropes, multiple polymorphs of borophene, germanene, and many others. The future of 2D materials goes beyond synthesis and characterization of free standing materials and on to the construction of heterostructures or sophisticated multilayer devices. Knowledge about the resulting local structure and composition of such systems will be key to understanding and optimizing their performance characteristics.
2D materials do not have a repeating crystal structure which can be easily characterized using bulk methods and therefore a localized high resolution method is needed. Electron microscopy is well suited for characterizing 2D materials as a repeating coherent structure is not necessary to produce a measureable signal as may be the case for diffraction methods. A unique opportunity for fine local scale measurements in low dimensional systems exists with a specific class of materials known as ferecrystals, the rotationally disordered relative of misfit layer compounds. Ferecrystals provide an excellent test system to observe effects at heterostructure interfaces as the whole film is composed of interdigitated two dimensional layers. Therefore bulk methods can be used to corroborate local scale measurements.
From the qualitative interpretation of high resolution scanning transmission electron microscope (STEM) images to the quantitative application of STEM energy dispersive X-ray spectroscopy (EDX), this thesis uses numerous methods electron microscopy. The culmination of this work is seen at the end of the thesis where atomically resolved STEM-EDX hyperspectral maps could be used to measure element specific atomic distances and the atomically resolved fractional occupancies of a low dimensional alloy. These local scale measurements are corroborated by additional experimental data. The input of multiple techniques leads to improved certainty in local scale measurements and the applicability of these methods to non-ferecrystal low dimensional systems.
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Hubbard, Philip J. "Understanding biomineralization of polycaprolactone surfaces." Thesis, Queensland University of Technology, 2018. https://eprints.qut.edu.au/119039/1/Philip_Hubbard_Thesis.pdf.
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This thesis explored both a method to fabricate new model systems of the gut using 3D printing (Universiteit Utrecht, UU), and the fundamental mechanisms behind a coating process used to improve the qualities of 3D-printed scaffolds for bone regeneration applications (Queensland University of Technology, QUT). More specifically, the projects involved using stereolithography (SLA) technology to produce a "midi-gut" representative of intestinal architecture for cell seeding at UU, and investigating and optimising calcium phosphate coating on polycaprolactone surfaces at QUT. This thesis corresponds to the dual Master in Biofabrication programme, carried out between UU (Utrecht, Netherlands) and QUT (Brisbane, Australia).
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Sakamoto, Silmara Sanae [UNESP]. "Identificação de elementos traço em tumores de mama de cadelas e sua correlação com histopatologia e prognóstico de vida." Universidade Estadual Paulista (UNESP), 2011. http://hdl.handle.net/11449/94699.
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sakamoto_ss_me_araca.pdf: 2232778 bytes, checksum: 2d567023e0bd2b444f0d70e7197d8eaf (MD5)<br>Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)<br>Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)<br>O papel dos elementos traço em tumores mamários tem sido investigado nas últimas décadas, mas comparações de subclasses de tumores mamários malignos são ainda inéditas em medicina veterinária. Portanto, o objetivo do presente trabalho foi identificar a concentração dos elementos cálcio, ferro, cobre e zinco em neoplasias mamárias de cadelas, comparando-se um grupo controle com três tipos histológicos malignos. Cinquenta e uma biopsias mamárias foram avaliadas e divididas em quatro grupos (G1 - controle, G2 - carcinoma complexo, G3 - carcinoma tubular/tubulopapilífero e G4 – carcinoma sólido). O material foi colhido de mastectomias realizadas na rotina do Hospital Veterinário da UNESP-Araçatuba sendo classificado segundo os critérios diagnósticos propostos pela Organização Mundial de Saúde. As amostras foram analisadas, quanto aos elementos traço, pela técnica de Fluorescência de Raios X por Dispersão de Energia (EDXRF). A análise estatística revelou aumento significativo (p<0,05) dos elementos cálcio, ferro e zinco entre os grupos G1 e G2. Comparações entre o sistema TNM (Tumor/Linfonodo/Metástases) e os elementos traço não foram significativas (p˃0,05) à análise estatística, já que os mesmos demonstraram estar correlacionados ao tipo histológico e não ao sistema TNM de prognóstico de vida. O aparelho de EDXRF mostrou-se eficaz para a análise dos elementos traço, além de ser uma técnica mais acessível, multielementar e não destrutiva, permitindo que outras metodologias possam ser utilizadas para estudos complementares com as mesmas amostras<br>The role of trace elements in breast cancer has been investigated in recent decades, but comparisons of subclasses of malignant mammary tumors are still unpublished in veterinary medicine. So, the aim of this work was to identify the concentration of calcium, iron, cooper and zinc in canine mammary tumors, comparing them with a control group and three malignant neoplasias. 51 mammary fragments of biopsies were analyzed and divided in four groups (G1 – Control, G2 - Complex Carcinomas, G3 – Tubular/Tubulopapillary Carcinoma and G4 – Solid Carcinoma). Samples of the tumors were collected during surgical procedures, mastectomy, performed at Veterinary Hospital of Sao Paulo State University – Araçatuba and were classified according to the diagnostic criteria proposed by the World Health Organization. Samples were analyzed by Energy Dispersive X-Ray Fluorescence Equipment (EDXRF). Statistical analysis revealed a significant difference (p<0.05) only in the groups G1 and G2, concerning to the calcium, iron and zinc elements. The comparison between TNM system and trace elements revealed an absence of statistical evaluation, because trace elements were connected with histopathologycal graduation. The EDXRF was useful for trace element analyses and it is a non-destructive, multielementar technology that permits complementary studies with the same samples
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Sakamoto, Silmara Sanae. "Identificação de elementos traço em tumores de mama de cadelas e sua correlação com histopatologia e prognóstico de vida /." Araçatuba : [s.n.], 2011. http://hdl.handle.net/11449/94699.
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Resumo: O papel dos elementos traço em tumores mamários tem sido investigado nas últimas décadas, mas comparações de subclasses de tumores mamários malignos são ainda inéditas em medicina veterinária. Portanto, o objetivo do presente trabalho foi identificar a concentração dos elementos cálcio, ferro, cobre e zinco em neoplasias mamárias de cadelas, comparando-se um grupo controle com três tipos histológicos malignos. Cinquenta e uma biopsias mamárias foram avaliadas e divididas em quatro grupos (G1 - controle, G2 - carcinoma complexo, G3 - carcinoma tubular/tubulopapilífero e G4 - carcinoma sólido). O material foi colhido de mastectomias realizadas na rotina do Hospital Veterinário da UNESP-Araçatuba sendo classificado segundo os critérios diagnósticos propostos pela Organização Mundial de Saúde. As amostras foram analisadas, quanto aos elementos traço, pela técnica de Fluorescência de Raios X por Dispersão de Energia (EDXRF). A análise estatística revelou aumento significativo (p<0,05) dos elementos cálcio, ferro e zinco entre os grupos G1 e G2. Comparações entre o sistema TNM (Tumor/Linfonodo/Metástases) e os elementos traço não foram significativas (p˃0,05) à análise estatística, já que os mesmos demonstraram estar correlacionados ao tipo histológico e não ao sistema TNM de prognóstico de vida. O aparelho de EDXRF mostrou-se eficaz para a análise dos elementos traço, além de ser uma técnica mais acessível, multielementar e não destrutiva, permitindo que outras metodologias possam ser utilizadas para estudos complementares com as mesmas amostras<br>Abstract: The role of trace elements in breast cancer has been investigated in recent decades, but comparisons of subclasses of malignant mammary tumors are still unpublished in veterinary medicine. So, the aim of this work was to identify the concentration of calcium, iron, cooper and zinc in canine mammary tumors, comparing them with a control group and three malignant neoplasias. 51 mammary fragments of biopsies were analyzed and divided in four groups (G1 - Control, G2 - Complex Carcinomas, G3 - Tubular/Tubulopapillary Carcinoma and G4 - Solid Carcinoma). Samples of the tumors were collected during surgical procedures, mastectomy, performed at Veterinary Hospital of Sao Paulo State University - Araçatuba and were classified according to the diagnostic criteria proposed by the World Health Organization. Samples were analyzed by Energy Dispersive X-Ray Fluorescence Equipment (EDXRF). Statistical analysis revealed a significant difference (p<0.05) only in the groups G1 and G2, concerning to the calcium, iron and zinc elements. The comparison between TNM system and trace elements revealed an absence of statistical evaluation, because trace elements were connected with histopathologycal graduation. The EDXRF was useful for trace element analyses and it is a non-destructive, multielementar technology that permits complementary studies with the same samples<br>Orientador: Alexandre Lima de Andrade<br>Coorientador: Maria Cecília Rui Luvizotto<br>Coorientador: Andrea Antunes Pereira<br>Banca: Flávia de Rezende Eugênio<br>Banca: Paula Rahal<br>Mestre
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Gorce, Jean-Philippe. "Crystallisation and chain conformation of long chain n-alkanes." Thesis, Sheffield Hallam University, 2000. http://shura.shu.ac.uk/19705/.
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Hydrocarbon chains are a basic component in a number of systems as diverse as biological membranes, phospholipids and polymers. A better understanding of the physical properties of n-alkane chains should provide a better understanding of these more complex systems. With this aim, vibrational spectroscopy has been extensively used. This technique, sensitive to molecular details, is the only one able to both identify and quantify conformational disorder present in paraffinic systems. To achieve this, methyl deformations have been widely used as "internal standards" for the normalisation of peak areas. However, in the case of n-alkanes with short chain length, such as n-C[44]H[90] for example, the infrared spectra recorded at liquid nitrogen temperature and reported here show the sensitivity of these latter peaks to the various crystal structures formed. Indeed, the main frequencies of the symmetric methyl bending mode were found between 1384 cm[-1] and 1368 cm[-1] as a function of the crystal form. Changes in the frequency of the first order of the L.A.M. present in the Raman spectra were also observed. At higher temperatures, non all-trans conformers, inferred from different infrared bands present in the wagging mode region, were found to be essentially placed at the end of the n-alkane chains. At the monoclinic phase transition, the concentration of end-gauche conformers, proportional to the area of the infrared band at 1342 cm[-1], increases abruptly. On the contrary, in the spectra recorded at liquid nitrogen temperature no such band is observed. We also studied the degree of disorder in two purely monodisperse long chain n-alkanes, namely n-C[198]H[398] and n-C[246]H[494]. The chain conformation as well as the tilt angle of the chains from the crystal surfaces were determined by means of low frequency Raman spectroscopy and S.A.X.S. measurements on solution-crystallised samples. The increase in the number of end-gauche conformers which was expected to occur with the increase of the tilt angle as a function of the temperature was not detected due to a perfecting of the crystals. Indeed, due to successive heating and cooling to -173°C, the concentration of non all-trans conformers was found to decrease within the crystals. Their numbers were found to be up to six times higher in n-C[198]H[398] crystallised in once folded form than when crystallised in extended form. The C-C stretching mode region of the spectra was used to identify the chain conformation and to estimate the length of the all-trans stem passing through the crystal layers at -173°C. The transition between once folded and extended form crystals was indicated by the presence of additional bands in this region at 1089 cm[-1], 1078 cm[-1] and 1064 cm[-1]. Some of those bands may be related to the fold itself. At the same time, a strong decrease of the intensity of the infrared bands present in the wagging mode region was observed. Finally, the triple layered structure proposed on the basis of X-ray measurements obtained from the crystals of a binary mixture of long chain n-alkanes, namely n-C[162]H[326] and n-C[246]H[494], was confirmed from the study of the C-C stretching mode region of the infrared spectra.
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Leek, Darrell Stewart. "A study of the effects of chloride and sulphate on the hydration of portland cement and the corrosion of carbon steel reinforcement using electron-optical techniques and energy dispersive X-ray analysis." Thesis, Queen Mary, University of London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265400.
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Junior, Sergio Matias Pereira. "Determinação de cobre, cromo e arsênio em madeira preservada (Eucalyptus sp.) pelas espectrometrias de fluorescências de raios X." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/85/85134/tde-09022015-095042/.
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O Brasil produz cerca de 2,2 milhões de metros cúbicos de madeira preservada para atender à demanda anual nos setores de transporte ferroviário, elétrico, rural e de construção civil. As espécies de madeiras mais usados são do eucalipto (Eucalyptus sp.) e pinus (Pinus sp.). A madeira preservada, utilizada para postes, dormentes, mourões e nas construções em madeira, deve estar em conformidade com as especificações exigidas pelas normas brasileiras quanto ao seu tratamento preservativo. No Brasil, os preservativos de madeira mais utilizados e regulamentados são CCA (arseniato de cobre cromatado) e o CCB (sal de cobre cromo e boro). As técnicas analíticas como espectrometria de absorção atómica de chama (FAAS) e espectrometria de emissão de plasma acoplado (ICPOES) e espectrometria de fluorescência de raios x (XRFS) são utilizadas para a avaliação desses processos. Neste trabalho, as amostras de madeira foram obtidas de árvores de eucalipto (Eucalyptus sp.), provenientes de áreas de plantação do estado de Minas Gerais, Brasil. Amostras de madeira de eucalipto foram submetidas a diferentes concentrações de solução de CCA, sob pressão, atingindo retenções de 3,9; 6,7; 9,1; 12,4 e 14,0 kg de CCA por m-³ de alburno. A partir dos blocos tratados foram obtidos amostras em forma de cilindros e serragem. A determinação de cobre, cromo e arsênio foi realizada pela espectrometria de fluorescência de raios X de energia dispersiva (EDXRF), espectrometria de fluorescência de raios X portátil (PXRF), FAAS e IAAN. Neste trabalho, foram avaliados métodos de análise, sensibilidade e precisão, exatidão das técnicas analíticas relacionadas.<br>Brazil produces around 2.2 millions of cubic meters of treated wood to meet the annual demand of railway, electric, rural and construction sectors. The most used wood species are eucalyptus (Eucalyptus ssp.) and pine (Pinus ssp.).The treated woods used for poles, sleepers, fence posts and plywoods should be according to Brazilian norms requirements. The most usual wood preservative products used in Brazil are CCA (chromated copper arsenate) and CCB (copper chromium and boron salt). The analytical methods, such as flame atomic absorption spectrometry (FAAS), plasma inductively coupled optical emission spectrometry (ICPOES) and X-ray fluorescence spectrometry (XRFS) have been used for the analytical control of those treatment processes. In this work, the eucalyptus trees (Eucalyptus ssp) samples was obtained from Minas Gerais State, Brazil, cut plantation areas. Under pressure, eucalyptus wood samples were submitted to different concentration of CCA solution reaching 3.9, 6.7, 9.1, 12.4 and 14.0 kg of CCA by m-³ sapwood retentions. Samples in cylinders and sawdust forms were obtained from treated wood samples. Copper, chromium and arsenic determination was performed using the energy dispersive X-ray fluorescence spectrometry (EDXRFS), portable X-ray fluorescence spectrometry (PXRFS), flame atomic absorption spectrometry (FAAS) and instrumental neutron activation analysis. In this work, the method of analysis, sensitivity, precision and accuracy performances of the related techniques were outlined.
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MAEDA, NANCY T. "Avaliação da neoformação óssea em tíbia de coelhos utilizando cúpula de hidroxiapatita associada a diferentes biomateriais." reponame:Repositório Institucional do IPEN, 2013. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10542.
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Made available in DSpace on 2014-10-09T12:41:41Z (GMT). No. of bitstreams: 0<br>Made available in DSpace on 2014-10-09T14:07:15Z (GMT). No. of bitstreams: 0<br>Dissertação (Mestrado)<br>IPEN/D<br>Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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Bento, Carlos Alberto da Silva. "Estudo da interface Ti-6Al-4V/TiO2 por microscopia eletrônica de varredura." Universidade de São Paulo, 2000. http://www.teses.usp.br/teses/disponiveis/88/88131/tde-13122001-151942/.
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A liga Ti-6Al-4V tem sido usada com sucesso como biomaterial com aplicações nos campos da odontologia e ortopedia. As características da liga Ti-6Al-4V que a tornaram um material interessante são sua boa resistência à corrosão em meio biológico, combinada com um excelente grau de biocompatibilidade. Os efeitos biológicos a longo prazo dos íons metálicos resultantes da lenta lixiviação dos implantes de titânio não estão completamente entendidos. É conhecido que os íons titânio são considerados agentes químicos cancerígenos, os íons alumínio causam desordem neurológicas e os íons vanádio estão associados com distúrbios enzimáticos, entre outros problemas. O recobrimento das ligas de titânio por óxido de titânio (TiO2) pode atuar como uma barreira química para os íons lixiviados da superfície metálica da liga, além deste óxido ser um bom osseoindutor. O processo de aspersão térmica é amplamente empregado na aplicação de recobrimentos por óxidos. Uma vez que este processo acontece em altas temperaturas, onde partículas fundidas ou semi-fundidas aderem ao substrato, pode ocorrer difusão localizada. O objetivo deste estudo é caracterizar a interdifusão dos elementos de liga através das camadas superficiais do sistema Ti-6Al-4V/TiO2. Os recobrimentos de TiO2 foram preparados pela técnica de aspersão por plasma. A zona recoberta mostrou pequena porosidade distribuída por toda a camada e algumas trincas radiais. Adicionalmente, uma grande quantidade de buracos foi observada na região entre-camadas. Neste trabalho, a interface Ti-6Al-4V/TiO2 foi estudada por microscopia eletrônica de varredura. Os perfis de difusão do Ti, Al, V e O nas camadas superficiais da amostra recoberta foram obtidos por microanálise semi-quantitativa por energia dispersiva de raios-X. A caracterização química superficial do lado substrato depois da deposição de TiO2 mostrou a formação localizada de TiO. Na região entre-camadas foram observados os perfis de difusão característicos com forma de S para o Ti, V e O. O perfil de difusão do Al mostrou um pico na região entre-camadas indicando um acúmulo de Al2O3 nos buracos presentes nesta zona. O TiO2 foi identificado como o maior constituinte no lado revestimento. Pequenas quantidades de Al e V foram também detectadas homogeneamente distribuídas dentro do depósito. A presença do Al e V (metais tóxicos) na superfície externa do depósito indica que estes metais não competem com a oxidação da camada depositada indicando um efeito desmascarante da superfície da liga metálica pelo óxido superficial TiO2.<br>Ti-6Al-4V alloy has been used with some success as biomaterial with applications in the field of dentistry and orthopaedics. The features with make the Ti-6Al-4V alloy such an interesting material are its good corrosion resistance in the biological environment, combined with an excellent degree of biocompatibility. The long-term biological effects of the slowly leaching of metal ions from titanium implants are not completely understood. It is known that the titanium ions are considered chemical carcinogen, aluminium ions cause neurological disorders and, vanadium ions are associated with irreversible enzymatic disturbance, among other problems. Titanium oxide (TiO2) coatings on titanium alloys can act as a chemical barrier for ions leaching from the metallic alloy surface, beside the fact that this oxide is a very good osteoinductor. The thermal spray process is widely used to apply oxide coatings. Once this is a high temperature process where molten or semi-molten particles impinge upon the substrate, localized diffusion can occur. The aim of this study is characterize the inter-diffusion of the alloying elements through the surface layers of the system Ti-6Al-4V/TiO2. The TiO2 coatings were prepared by the plasma spray technique. The coated zone showed some porous distributed in all layer and a few radial cracks. Additionally, large amount of holes were observed in the interlayer region. In this work, the interface Ti-6Al-4V/TiO2 was studied by scanning electron microscopy. Diffusion profiles of Ti, Al, V and O in the surface layers of coated samples were measured by semi-quantitative energy dispersive X-ray microanalysis. Chemical surface characterization of the substrate side after the TiO2 deposition showed the localized formation of TiO. At the interlayer region was observed the characteristic S shape diffusion profiles for Ti, V and O. The Al diffusion profile showed a peak in the interlayer region indicating anaccumulation of Al2O3 into the holes present in this zone. TiO2 was identified as the major component in the coating side. Small amounts of Al and V were also detected homogeneously distributed inside the deposit. Presence of Al and V (toxic metals) on the external surface of the deposit indicated that these metals did not compete with the oxidation of the deposited layer indicating a non-masking effect of metallic alloy surface by the TiO2- surface oxide.
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Lu, Shifeier. "Analytical study of osteoporosis of maxilla in ovariectomized rats." Thesis, Queensland University of Technology, 2015. https://eprints.qut.edu.au/88474/1/Shifeier_Lu_Thesis.pdf.
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The project applied analytical facilities to characterize the composition and mechanical properties of osteoporosis in maxillary bone using an ovariectomized rat model. It was found that osteoporotic jaw bone contained different amount of trace elements in comparison with the normal bone, which plays a significant role in bone quality. The knowledge generated from the study will assist the treatment of jaw bone fracture and dental implant placement.
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SILVA, NETO Oscar Gomes da. "Extração e avaliação das propriedades físicas, quimicas e biológicas do gel de aloe vera para aplicação em ecografia." Universidade Federal de Campina Grande, 2018. http://dspace.sti.ufcg.edu.br:8080/jspui/handle/riufcg/1028.
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Previous issue date: 2018-06-21<br>A ecografia é um dos métodos de diagnóstico por imagem mais versátil e difundido na
atualidade, de aplicação relativamente simples, basear-se no fenômeno de interação de
uma onda mecânica com os tecidos corporais, ou seja, observa as propriedades
mecânicas dos tecidos ao longo da propagação da onda pelos mesmos, necessitando de
um gel de acoplamento acústico para aumentar o contato entre a pele e o aparelho. A
Aloe vera (Aloe barbadensis Miller) é uma planta suculenta perene, que desenvolve um
tecido de armazenamento de água no interior das folhas, o gel, para sobreviver em zonas áridas de pluviosidade baixa ou irregular. Desta forma, este trabalho objetivou a extração do gel de Aloe vera, com subsequente análise de suas propriedades físicas, químicas e biológicas. Foram realizados testes de avaliação da sua funcionalidade para aquisição de imagens por ecografia e, por fim, realizado estudo comparativo com imagens ecográficas adquiridas com o gel de Aloe vera e com o gel comercial atualmente utilizado. O gel de Aloe Vera a 100% foi extraído da própria planta, processado e caracterizado por espectroscopia na Região do Infravermelho com Transformada de Fourier (FTIR), espectroscopia por Energia Dispersiva de raios X (EDS), Ensaio de Citotoxicidade e Ecografia. As análises foram realizadas no Laboratório de Desenvolvimento e Avaliação de Biomateriais (CERTBIO). O gel de Aloe vera quando utilizado para fins de obtenção de imagem, apresentou resultado igual ou superior às imagens obtidas com o gel comercial, podendo ter ocorrido devido a menor resistência oferecida pelo mesmo e consequentemente maior condutividade, provavelmente pela maior quantidade de íons livres, permitindo a diminuição da impedância do transdutor em relação à pele, promovendo a propagação do ultrassom desde o transdutor até os órgãos avaliados. Com base nos resultados obtidos nos ensaios de Espectroscopia na Região do Infravermelho com Transformada de Fourier, Espectroscopia por Energia Dispersiva de raios X, Citotoxicidade e Exames Ecográficos, pode-se concluir que os materiais
apresentam características semelhantes, indicando que o gel de Aloe vera possa ser utilizado em exames de ultrassonografia.<br>Ultrasound is a diagnostic methods for more versatile and widespread image today,
relatively simple application, be based on the interaction phenomenon of a mechanical wave with body tissues, ie observe the mechanical properties of tissues along the Wave propagation through the same, necessitating an acoustic coupling gel to increase the contact between the skin and the device. Aloe vera (Aloe barbadensis Miller) is a succulent perennial plant which develops a water storage tissue sheets within the gel, to survive in arid zones of low rainfall or irregular. Thus, this study aimed to extract the gel of Aloe vera, with subsequent analysis of their physical, chemical and biological properties, as well as evaluation tests were carried out of its functionality for image acquisition by ultrasound and finally performed study comparison with ultrasound images acquired with the gel of Aloe vera and commercial gel currently used. The gel of Aloe Vera 100% was extracted from the plant itself, processed and characterized by Spectroscopy in Infrared Region Fourier Transform (FTIR) Spectroscopy Energy Dispersive X-ray (EDS), Cytotoxicity and ultrasound test. The analyzes were performed at the Development Laboratory and Biomaterials Assessment (CERTBIO). The Aloe vera gel when used for the purpose of obtaining image presented results equal to or better than the images obtained with the commercial gel and this may be due to lower resistance of the same and therefore higher conductivity and this can probably allow the reduction of the impedance of the transducer relative to the skin, promoting the propagation of ultrasound from the transducer to the evaluated organs. Since based on the results obtained in tests spectroscopy in the infrared Fourier transform spectroscopy, by Energy Dispersive X-ray, ultrasound examinations and cytotoxicity, it can be concluded that the materials have similar characteristics indicative that the aloe vera gel may be used on ultrasound examination.