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1
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.
3
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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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.
5
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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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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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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Green, Heather F. "Casting no shadow : overlapping soilscapes of European-Indigenous interaction in northern Sweden." Thesis, University of Stirling, 2012. http://hdl.handle.net/1893/13133.
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The Sámi’s past activities have been documented historically from a European perspective, and more recently from an anthropological viewpoint, giving a generalised observation of the Sámi, during the study period of AD200-AD1800, as semi-nomadic hunter gatherers, with several theories suggesting that interaction with Europeans, through trade, led to the adoption of European activities by certain groups of the Sámi (Eiermann, 1923; Paine, 1957; Manker and Vorren, 1962; Bratrein, 1981; Mathiesen et al, 1981; Meriot, 1984). However, there is almost no information on the impact the Sámi had on the landscape, either before or after any adoption of European activities, and none investigating what cultural footprint or indicators would remain from Sámi or European occupation and/or activity within the typically podzolic soils of Northern Sweden. Consequently the thesis aims to contribute to the gap in knowledge through the formation of a podzol model identifying the links between anthropogenic activity and the alteration of podzol soils, and through the creation of soils based models which identify the cultural indicators associated with both Sámi and European activity; formed from the identification of cultural indicators retained within known Sámi and European sites. The methods used to obtain the information needed to achieve this were the pH and magnetic susceptibility from bulk soil samples and micromorphological and chemical analysis of thin section slides through the use of standard microscopy and X-ray fluorescence from a scanning electron microscope. The analysis revealed that the Sámi had an extremely low impact on the landscape, leaving hard to detect cultural indicators related to reindeer herding in the form of reindeer faecal material with corresponding phosphorous peaks in the thin section slides. The European footprint however, was markedly different and very visible even within the acidic soil environment. The European indicators were cultivation based and included phosphorous and aluminium peaks as well as a deepened, highly homogenised plaggen style anthropogenic topsoil rich in ‘added’ materials. An abandoned European site which visibly and chemically shows the formation of a secondary albic horizon within the anthropogenic topsoil also provides an insight into the delicate balance of cultivated soil in northern Sweden, whilst reinforcing the outputs identified in the podzol model. Due to the almost invisible Sámi footprint on the landscape, areas of overlap were impossible to identify however, there was no evidence of the adoption of European cultivation activities at any of the Sámi sites investigated. The only known area of interaction between the two cultures was an official market place which had been a Sámi winter settlement prior to its use as a market site. This site showed none of the reindeer based Sámi indicators or the cultivation based European indicators, but did contain pottery fragments which could be linked to trade or occupation. Overall, the thesis reinforces the low impact expected of the semi-nomadic Sámi and sheds light on the underlying podzolic processes influencing the anthropogenically modified soils of Northern Sweden. The podzol model is reinforced by several findings throughout the thesis and the soils based cultural indicator models for both Sámi and European activity have been successfully tested against independent entomological and palynological data and therefore provide reliable reference material for future studies.
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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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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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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&ndash160 K with various heating rates between 0.6&ndash
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
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.
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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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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 0.13×10-3-110.34 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
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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Zhang, Shuo. "The Performance and Service Life Prediction of High Performance Concrete in Sulfate and Acidic Environments." FIU Digital Commons, 2015. http://digitalcommons.fiu.edu/etd/2260.
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Concrete substructures are often subjected to environmental deterioration, such as sulfate and acid attack, which leads to severe damage and causes structure degradation or even failure. In order to improve the durability of concrete, the High Performance Concrete (HPC) has become widely used by partially replacing cement with pozzolanic materials. However, HPC degradation mechanisms in sulfate and acidic environments are not completely understood. It is therefore important to evaluate the performance of the HPC in such conditions and predict concrete service life by establishing degradation models.
This study began with a review of available environmental data in the State of Florida. A total of seven bridges have been inspected. Concrete cores were taken from these bridge piles and were subjected for microstructural analysis using Scanning Electron Microscope (SEM). Ettringite is found to be the products of sulfate attack in sulfate and acidic condition.
In order to quantitatively analyze concrete deterioration level, an image processing program is designed using Matlab to obtain quantitative data. Crack percentage (Acrack/Asurface) is used to evaluate concrete deterioration. Thereafter, correlation analysis was performed to find the correlation between five related variables and concrete deterioration. Environmental sulfate concentration and bridge age were found to be positively correlated, while environmental pH level was found to be negatively correlated.
Besides environmental conditions, concrete property factor was also included in the equation. It was derived from laboratory testing data. Experimental tests were carried out implementing accelerated expansion test under controlled environment. Specimens of eight different mix designs were prepared. The effect of pozzolanic replacement rate was taken into consideration in the empirical equation. And the empirical equation was validated with existing bridges.
Results show that the proposed equations compared well with field test results with a maximum deviation of ± 20%. Two examples showing how to use the proposed equations are provided to guide the practical implementation. In conclusion, the proposed approach of relating microcracks to deterioration is a better method than existing diffusion and sorption models since sulfate attack cause cracking in concrete. Imaging technique provided in this study can also be used to quantitatively analyze concrete samples.
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Sampaio, Felipe Cavalcanti. "Microanálise de superfície e caracterização química de cimentos endodônticos." Universidade Federal de Goiás, 2013. http://repositorio.bc.ufg.br/tede/handle/tede/8569.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
Purpose: to assess the surface and evaluate the chemical composition of root canal filling materials by scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). Methods: eighteen polyethylene standard tubes were filled with the tested materials: Sealapex®, Sealer 26®, MTA Fillapex®, Pulp Canal Sealer®, Endofill® and AH Plus®. After 48 hours at 37°C and 95% relative humidity, the samples were surface-sputtered with gold, led to SEM and the images analyzed at 5,000X magnification. Then, the elements distribution and chemical composition were determined by EDX. The results were evaluated qualitatively (SEM images and elements distribution maps) and quantitatively (weight percentage). Results: the surface analysis revealed that the sealers presented different regularities, with an uniform distribution of elements, with particles of similar sizes and variable shapes in EDX microanalysis. Calcium oxide and hydroxide based sealers (Sealapex® and Sealer 26®) presented calcium peaks of 53.58wt.% and 65.00wt.%, respectively. MTA Fillapex® presented 30.58wt.% of calcium and high amounts of silicon (31.02 weight%) and bismuth (27.38 weight%). Zinc oxide and eugenol based sealers, Pulp Canal Sealer® and Endofill®, showed zinc quantities of 67.74wt% and 63.16wt.%, respectively. AH Plus® had higher amount of zirconium (64.24wt.%). The materials presented elements incompatible with the composition described by the manufacturer. Conclusions: the root canal sealers’ surfaces showed different. The elements presented uniform distribution, with particles of similar sizes and variable shapes. Chemical elements were found in the root canal sealers not described by the manufacturers.
Objetivo: analisar a superfície e avaliar a composição química de materiais obturadores do canal radicular por meio de microscopia eletrônica de varredura (MEV) e espectroscopia de dispersão de raios-X (EDX). Material e métodos: dezoito tubos de polietileno padronizados foram preenchidos com os materiais avaliados (n=3): Sealapex®, Sealer 26®, MTA Fillapex®, Pulp Canal Sealer®, Endofill® e AH Plus®. Após 48 horas a 37°C e umidade relativa de 95%, as amostras foram metalizadas com ouro, conduzidas ao MEV e as imagens da superfície analisadas em um aumento de 5.000X. A seguir, a distribuição dos elementos e composição química foram determinadas por meio de EDX. Os resultados foram avaliados qualitativamente (imagens do MEV e mapas de distribuição de elementos) e quantitativamente (porcentagem em peso). Resultados: a análise da superfície revelou que os cimentos apresentaram diferentes regularidades em imagens por MEV. As partículas apresentaram-se com distribuição uniforme dos elementos, com tamanhos similares e formas variáveis em microanálises por EDX. Os cimentos à base de óxido ou hidróxido de cálcio (Sealapex® e Sealer 26®) apresentaram quantidades de cálcio de 53,58%p (porcentagem de peso atômico) e 65,00%p, respectivamente, em microanálises por EDX. O cimento MTA Fillapex® apresentou 30,58%p de cálcio e elevadas quantidades de silício (31,02%p) e bismuto (27,38%p). Os cimentos contendo óxido de zinco e eugenol, Pulp Canal Sealer® e Endofill®, apresentaram zinco em quantidades de 67,74%p e 63,16%p, respectivamente. O AH Plus® apresentou maior quantidade de zircônia (64,24%p). Foram encontrados elementos não compatíveis com a composição descrita pelo fabricante. Conclusões: as superfícies dos cimentos endodônticos mostraram diferentes regularidades. As partículas apresentaram distribuição uniforme, com tamanhos similares, porém com formas variadas. Foram encontrados nos cimentos endodônticos elementos químicos que não foram descritos pelos fabricantes.
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Haibo, E. "Quantitative analysis of core-shell nanoparticle catalysts by scanning transmission electron microscopy." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:19c3b989-0ffb-487f-8cb3-f6e9dea83e63.
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This thesis concerns the application of aberration corrected scanning transmission electron microscopy (STEM) to the quantitative analysis of industrial Pd-Pt core-shell catalyst nanoparticles. High angle annular dark field imaging (HAADF), an incoherent imaging mode, is used to determine particle size distribution and particle morphology of various particle designs with differing amounts of Pt coverage. The limitations to imaging, discrete tomography and spectral analysis imposed by the sample’s sensitivity to the beam are also explored. Since scattered intensity in HAADF is strongly dependent on both thickness and composition, determining the three dimensional structure of a particle and its bimetallic composition in each atomic column requires further analysis. A quantitative method was developed to interpret single images, obtained from commercially available microscopes, by analysis of the cross sections of HAADF scattering from individual atomic columns. This technique uses thorough detector calibrations and full dynamical simulations in order to allow comparison between experimentally measured cross section to simulated ones and is shown to be robust to many experimental parameters. Potential difficulties in its applications are discussed. The cross section approach is tested on model materials before applying it to the identification of column compositions of core-shell nanoparticles. Energy dispersive X-ray analysis is then used to provide compositional sensitivity. The potential sources of error are discussed and steps towards optimisation of experimental parameters presented. Finally, a combination of HAADF cross section analysis and EDX spectrum imaging is used to investigate the core-shell nanoparticles and the results are correlated to findings regarding structure and catalyst activity from other techniques. The results show that analysis by cross section combined with EDX spectrum mapping shows great promise in elucidating the atom-by-atom composition of individual columns in a core-shell nanoparticle. However, there is a clear need for further investigation to solve the thickness / composition dualism.
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Kleinhans, Henrik. "Evaluation of the Carbonization of Thermo-Stabilized Lignin Fibers into Carbon Fibers." Thesis, Linköpings universitet, Kemi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-120519.
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Thermo-stabilized lignin fibers from pH-fractionated softwood kraft lignin were carbonized to various temperatures during thermomechanical analysis (TMA) under static and increasing load and different rates of heating. The aim was to optimize the carbonization process to obtain suitable carbon fiber material with good mechanical strength potential (high tensile strength and high E-modulus). The carbon fibers were therefore mainly evaluated of mechanical strength in Dia-Stron uniaxial tensile testing. In addition, chemical composition, in terms of functional groups, and elemental (atomic) composition was studied in Fourier transform infrared spectroscopy (FTIR) and in energy-dispersive X-ray spectroscopy (EDS), respectively. The structure of carbon fibers was imaged in scanning electron microscope (SEM) and light microscopy. Thermogravimetrical analysis was performed on thermo-stabilized lignin fibers to evaluate the loss of mass and to calculate the stress-changes and diameter-changes that occur during carbonization. The TMA-analysis of the deformation showed, for thermo-stabilized lignin fibers, a characteristic behavior of contraction during carbonization. Carbonization temperatures above 1000°C seemed most efficient in terms of E-modulus and tensile strength whereas rate of heating did not matter considerably. The E-modulus for the fibers was improved significantly by slowly increasing the load during the carbonization. The tensile strength remained however unchanged. The FTIR-analysis indicated that many functional groups, mainly oxygen containing, dissociate from the lignin polymers during carbonization. The EDS supported this by showing that the oxygen content decreased. Accordingly, the relative carbon content increased passively to around 90% at 1000°C. Aromatic structures in the carbon fibers are thought to contribute to the mechanical strength and are likely formed during the carbonization. However, the FTIR result showed no evident signs that aromatic structures had been formed, possible due to some difficulties with the KBr-method. In the SEM and light microscopy imaging one could observe that porous formations on the surface of the fibers increased as the temperature increased in the carbonization. These formations may have affected the mechanical strength of the carbon fibers, mainly tensile strength. The carbonization process was optimized in the sense that any heating rate can be used. No restriction in production speed exists. The carbonization should be run to at least 1000°C to achieve maximum mechanical strength, both in E-modulus and tensile strength. To improve the E-modulus further, a slowly increasing load can be applied to the lignin fibers during carbonization. The earlier the force is applied, to counteract the lignin fiber contraction that occurs (namely around 300°C), the better. However, in terms of mechanical performance, the lignin carbon fibers are still far from practical use in the industry.
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Krummenauer, Alex. "Desenvolvimento e validação de metodologia analítica para análise de aços por espectrometria de fluorescência de raios X por dispersão de energia (EDXRF)." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2017. http://hdl.handle.net/10183/178232.
Full textAbstract:
O desenvolvimento e validação de métodos analíticos é um procedimento necessário quando um método não normalizado é utilizado por um laboratório de ensaios. A validação de métodos também é um requisito específico da norma ABNT NBR ISO/IEC 17025, que determina os requisitos gerais para a competência dos laboratórios de ensaio e calibração. O objetivo da validação é demonstrar que o método analítico, nas condições em que é executado, produz resultados com a exatidão requerida. O Laboratório de Corrosão, Proteção e Reciclagem de Materiais (LACOR), da UFRGS, tem o ensaio de determinação de metais por fluorescência de raios X, acreditado pelo CGCRE/INMETRO, conforme ABNT NBR ISO/IEC 17025. O ensaio é feito usando o método de espectrometria de fluorescência de raios X por dispersão de energia (EDXRF). Este método, contudo, não é normalizado e, portanto, o mesmo foi validado, neste trabalho de pesquisa, para atender a este requisito. A validação foi feita com base no documento orientativo DOQ-CGCRE-08 e no guia EURACHEM. Os parâmetros de validação, para o ensaio quantitativo por EDXRF, que foram calculados neste trabalho são: seletividade; limite de detecção (LD) e limite de quantificação (LQ); linearidade e faixa de trabalho; veracidade de medição (tendência, erro normalizado, Z-score e comparação com método de referência) e precisão (repetibilidade, precisão intermediária e reprodutibilidade). Além disso, foi desenvolvida uma metodologia de cálculo de incerteza de medição para o ensaio por EDXRF Os resultados obtidos neste estudo demonstram que o método EDXRF, usado na determinação de metais em aços, é um método não normalizado validado e compatível com os resultados obtidos com os métodos de referência: espectrometria de fluorescência de raios X por dispersão de comprimento de onda (WDXRF), fotométricos e espectrometria de absorção atômica (AAS). Inclusive, o WDXRF é um método de referência usado em muitas normas internacionais, que descrevem métodos de análise de aços por fluorescência de raios X, como ASTM E572 ou ASTM E1085. O estudo desenvolvido nesta dissertação permitiu que o LACOR mantivesse sua acreditação no ensaio de determinação de metais por fluorescência de raios X, na avaliação do CGCRE/INMETRO, no presente ano. Outros frutos deste trabalho foram a confecção das curvas de calibração do espectrômetro NITON XL3t GOLDD+ e a revisão do procedimento de ensaio, onde esses novos conhecimentos sobre a técnica EDXRF foram aplicados. Futuramente, este trabalho pode ser usado por outros pesquisadores para desenvolver estudos em outras matrizes metálicas, como cobre, alumínio, titânio ou níquel, e, também, em outras áreas de aplicação como jóias, reciclagem de materiais metálicos ou, até mesmo, para análise elementar de resíduos retidos em membranas de troca iônica.The development and validation of analytical methods is a required procedure when a non-standard method is used by a testing laboratory. Method validation is also a specific requirement of the ABNT NBR ISO / IEC 17025, which determines the general requirements for the competence of testing and calibration laboratories. The purpose of validation is to demonstrate that the analytical method, under the conditions in which it is performed, produces results with the required accuracy. The Corrosion, Protection and Recycling Materials Laboratory (LACOR), at UFRGS, has the X-ray fluorescence metal analysis, accredited by CGCRE / INMETRO, according to ABNT NBR ISO / IEC 17025. The test is performed using Energy Dispersive X-Ray Fluorescence spectrometry, EDXRF method. This method, however, is not standardized; therefore, it was validated in this research to meet this requirement. The validation was based on the DOQ-CGCRE-08 document and the EURACHEM guide. The method performance calculated in this study for quantitative testing by EDXRF are: selectivity; limit of detection (LOD) and limit of quantification (LOQ); linearity and working range; trueness (bias, normalized error, Z-score and comparison with reference method) and precision (repeatability, intermediate precision and reproducibility). In addition, a measurement uncertainty calculation methodology was developed for the EDXRF testing The results obtained in this study demonstrate that the EDXRF method, used in the determination in the chemical analysis of steels, is a validated non-standard method and compatible with the results obtained with the reference methods: Wavelength Dispersive X-Ray Fluorescence spectrometry (WDXRF), photometric and atomic absorption spectrometry (AAS). In addition, WDXRF is a reference method used in many international standards, which describes analysis of steels by X-ray fluorescence spectrometry such ASTM E572 or ASTM E1085. The study developed in this dissertation allowed LACOR to maintain its accreditation in the test of metal by X-ray fluorescence analysis, in the CGCRE / INMETRO audit, this year. Other fruits of this work were the preparation of calibration curves of NITON XL3t GOLDD + spectrometer and complete revision of testing procedure, where this new knowledge about the EDXRF technique was applied. In the future, this work can be used by other researchers to develop studies in other base metals such as copper, aluminum, titanium or nickel, and also in other areas of application such as jewelry, recycling of metallic materials or even for analysis elemental residues retained in ion exchange membranes.
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Chen, Yiqiang. "High-resolution microstructural and microanalysis studies to better understand the thermodynamics and diffusion kinetics in an advanced Ni-based superalloy RR1000." Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/highresolution-microstructural-and-microanalysis-studies-to-better-understand-the-thermodynamics-and-diffusion-kinetics-in-an-advanced-nibased-superalloy-rr1000(1d4e96e0-b362-484e-82cb-bec18cab850b).html.
Full textAbstract:
The commercial polycrystalline superalloy RR1000 developed for turbine disc applications contains a large number of alloying elements. This complex alloy chemistry is required in order to produce appropriate microstructures and the required mechanical properties, such that the most important strengthener γʹ displays complex alloy chemistry. The broad aim of this project is to develop an approach to measuring the composition of γʹ precipitates at a broad range of length scales from nanometres to hundreds of nanometres, and subsequently develop a better understanding of the role of thermodynamics and diffusion kinetics on γʹ phase separation and precipitate growth. A solution of the absorption-corrected EDX spectroscopy to spherical particles was developed in our work, therefore enabling the quantitative analysis of precipitates' composition using an absorption-corrected Cliff-Lorimer approach. By performing this quantification, size-dependent precipitate compositional variations were obtained. Examination of this quantitative approach was compared to thermodynamic calculations of primary γ' precipitates possessing equilibrium compositions. Given the development of semi-quantitative compositional measurements for spherical γʹ precipitates and that cooling is one of the most common and critical regimes in physical metallurgy of Ni-based superalloys, this approach was then applied to study the local compositional variations that are induced in γ' precipitates when the alloy RR1000 undergoes different cooling rates. These measured compositions have been compared to detailed thermodynamic calculations and provide new experimental evidence of the importance of the dominant role of aluminium antisite diffusion in determining the low-temperature growth kinetics of fine-scale γ' precipitates. We have applied a similar analysis approach to study the compositional variations of γʹ cores within the class of secondary precipitates upon cyclic coarsening and reversal coarsening. It was shown that supersaturated Co in secondary γʹ exhibits an overall trend towards the equilibrium but Co content can significantly increase as γʹ coarsens. It was demonstrated that the limited elemental diffusivity in γ and γʹ compared to the observed coarsening rate in the coarsening regime results in the long-lasting Co supersaturation in γʹ and builds up elemental enhancements or depletions. These inhomogeneous elemental distributions produce compressive elastic constraints on large-scale secondary γʹ, therefore inducing morphological instability of these γʹ and causing the reversal coarsening. These results enable us to better understand the role that both thermodynamics and limited diffusion kinetics plays in controlling the complex microstructures of γ' precipitates.
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Trueman, Anthony Roger. "Characterization and corrosion studies of high carbon tool steel/tungsten carbide metal matrix composites." Thesis, Queensland University of Technology, 1999.
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汪毓人. "Identification of Automotive Paint Chips by Pyrolysis/ Gas Chromatography (Py/GC) and Scanning Electron Microscopy/ Energy Dispersive X-Ray Analysis (SEM/EDX)." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/08134902094273720299.
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汪毓人. "Identification of Automitive Paint Chips by Pyrolysis/ Gas Chromatography (Py/GC) and Scanning Electron Microscopy/ Energy Dispersive X-Ray Analysis (SEM/EDX)." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/jjepa9.
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Carvalho, Patrícia Miguel da Silva. "Energy Dispersive X-ray Fluorescence Analysis Imaging—Development and Applications." Master's thesis, 2022. http://hdl.handle.net/10362/135615.
Full textAbstract:
The Energy Dispersive X-ray Fluorescence (EDXRF) analysis technique presents unique
features for elemental content evaluation of varied samples, such as its non-destructive
nature, high sensitivity, or reduced costs. Many EDXRF studies have been focused on the
determination of elemental concentration variations between normal and tumour tissues,
to compare and correlate findings with factors such as the type and the stage of tumours,
or the patients’ age and sex. Mapping elemental distributions may also provide insightful
information on these types of samples, namely the identification of regions of elemental
accumulation or depletion, and the demarcation of tumour margins, thus contributing to
the unbiased differentiation between normal and abnormal tissues.
The main goals of this work are to quantitatively determine the elemental content
in paired samples of normal and tumour human tissues, and to map the corresponding
elemental distributions. An improved methodology for the quantitative analysis of biological
tissues is introduced, to surpass existing limitations (e.g., reduced number of tissue
samples) that have lead to low-accuracy quantifications and statistically irrelevant conclusions.
Moreover, a Full-field Energy Dispersive X-ray Fluorescence (FF-XRF) imaging
spectrometer based on the 2D Thick-COBRA (2D-THCOBRA) micropattern gas detector
is presented as a novel, cost-effective tool of simple instrumentation, for detection and
mapping of elements in biological tissues.
Different sample sets of normal and tumour human tissues were analysed, and it
was possible to quantify concentration variations of light (e.g., K) and heavy elements
(e.g., Fe and Zn). However, the contribution of these results to cancer studies is minimal
due to the reduced number of analysed samples. To overcome this limitation, mirror
samples of "fresh" and paraffin embedded tissues were analysed, and it was verified that
the embedding process alters the elemental content of tissues. As such, the monitoring
of the elemental content of tissues throughout the process is suggested.
The FF-XRF imaging spectrometer based on the 2D-THCOBRA detector was used to
map paired samples of normal and tumour human tissues. Elements present in small
amounts (a few μg/g) were detected and the corresponding distributions were mapped.
Overall, the detected elements are evenly distributed on the samples’ surface, with the
exception of Ca in the lung tumour tissue. Throughout the analysed sample, calcium
deposits, a possible malignancy indicator, were identified. The imaging spectrometer
was also applied in the study of Zebrafish exposed to Mn, Se, and Pb. Heavy metal accumulation in the intestinal region was identified in all the analysed fish. Despite
the suitability of the system for these studies, the need to improve detection efficiency
remains. As such, the iFluX imaging spectrometer, with a large area X-ray panel based on
a redesigned 2D-THCOBRA structure, is introduced.As técnicas de análise por Fluorescência de Raios-X Dispersiva em Energia (EDXRF) apresentam características únicas para a avaliação do conteúdo elemental de diversas amostras, tais como o seu carácter não destrutivo, elevada sensibilidade ou custo reduzido. Muitos estudos têm-se focado na determinação de variações da concentração elemental entre tecidos normais e tumorais, para comparar e correlacionar resultados com diversos factores, como o tipo e estádio de tumores ou a idade e sexo dos doentes. O mapeamento da distribuição elemental poderá também providenciar informações importantes sobre este tipo de amostras, que contribuam para a diferenciação entre tecido com e sem patologia, através da identificação de regiões de acumulação ou depleção de elementos e da demarcação de margens tumorais. Os principais objectivos deste trabalho são a determinação da concentração elemental em amostras pareadas de tecidos com e sem patologia tumoral, e o mapeamento da distribuição elemental correspondente. Para tal, é introduzida uma metodologia melhorada para a quantificação elemental em tecidos biológicos, que permite ultrapassar as limitações (e.g., o número reduzido de amostras estudadas) que têm levado à obtenção de resultados pouco precisos e estatisticamente irrelevantes. Apresenta-se também um sistema de imagem full-field EDXRF (FF-XRF) baseado no detector gasoso micro-estruturado 2D Thick-COBRA (2D-THCOBRA), como uma alternativa inovadora, de instrumentação simples e custo reduzido, para detecção e mapeamento elemental em amostras biológicas. Foram analisados diferentes conjuntos de amostras de tecidos com e sem patologia tumoral, tendo sido possível quantificar a variação de elementos leves (e.g., K) e pesados (e.g., Fe e Zn). No entanto, a contribuição destes resultados para estudos de patologias tumorais é mínima devido ao número reduzido de amostras. De modo a ultrapassar esta limitação, foram analisadas amostras espelhadas de tecidos "frescos" e preservados em parafina. Verificou-se que este processo de preservação altera o contéudo elemental dos tecidos, propondo-se a sua monitorização em cada estágio. O sistema de imagem FF-XRF baseado no detector 2D-THCOBRA foi utilizado no mapeamento de amostras pareadas de tecido normal e tumoral. Foram detectados elementos presentes em quantidades reduzidas (alguns μg/g) e a sua distribuição foi mapeada. Verificou-se a distribuição homogénea de todos os elementos, à excepção de Ca em tecido tumoral do pulmão; e foram identificados aglomerados de cálcio que poderão ser uma característica de tumores malignos. O sistema FF-XRF foi também aplicado no mapeamento de peixes Zebra expostos a metais pesados, tendo sido verificada a acumulação de Mn, Se e Pb na zona intestinal dos peixes analisados. Apesar da adequação do sistema para este tipo de aplicações, permanece a necessidade de aumentar a eficiência de detecção. Neste sentido, é introduzido o sistema de imagem full-field iFluX, com um painel detector de raios-X de grande área baseado numa estrutura 2D-THCOBRA redesenhada.
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"Determination of Fe, Cu and Zn in human plasma by energy dispersive X-ray fluorescence spectrometry." Chinese University of Hong Kong, 1993. http://library.cuhk.edu.hk/record=b5887819.
Full textAbstract:
by Chan Wing-yee.Thesis (M.Phil.)--Chinese University of Hong Kong, 1993.
Includes bibliographical references (leaves 93-95).
ACKNOWLEDGEMENT --- p.i
ABSTRACT --- p.ii
Chapter CHAPTER 1 --- INTRODUCTION --- p.1
Chapter 1.1 --- General Introduction --- p.1
Chapter 1.2 --- "Clinical Significance of Fe, Cu and Zn" --- p.2
Chapter 1.3 --- Alternative Methods of Analysis --- p.5
Chapter 1.4 --- Principles of Energy Dispersive X-ray Fluorescence Spectrometry --- p.11
Chapter 1.5 --- Research Plan --- p.20
Chapter CHAPTER 2 --- EXPERIMENTAL --- p.22
Chapter 2.1 --- Energy Dispersive X-ray Fluorescence Analysis --- p.22
Chapter 2.1.1 --- Apparatus --- p.22
Chapter 2.1.2 --- Reagents --- p.25
Chapter 2.1.3 --- Procedure --- p.28
Chapter 2.2 --- Atomic Absorption Spectrometric Analysis --- p.32
Chapter 2.2.1 --- Apparatus --- p.32
Chapter 2.2.2 --- Reagents --- p.32
Chapter 2.2.3 --- Procedure --- p.34
Chapter CHAPTER 3 --- RESULTS AND DISCUSSION --- p.38
Chapter 3.1 --- Optimisation of Excitation Conditions --- p.38
Chapter 3.1.1 --- Effect of Filter --- p.38
Chapter 3.1.2 --- Effect of Tube Voltage --- p.43
Chapter 3.1.3 --- Effect of Tube Current --- p.44
Chapter 3.2 --- Optimisation of Preconcentration Procedure --- p.46
Chapter 3.2.1 --- Effect of Sample Area and Collimator Size --- p.46
Chapter 3.2.2 --- Effect of pH --- p.51
Chapter 3.2.3 --- Effect of Ligand Concentration --- p.54
Chapter 3.2.4 --- Effect of Mixing Time --- p.57
Chapter 3.2.5 --- Effect of Standing Time --- p.59
Chapter 3.2.6 --- Study of Sample Homogeneity --- p.61
Chapter 3.3 --- Optimisation for Deproteination --- p.63
Chapter 3.3.1 --- Effect of Different Protein Precipitants --- p.63
Chapter 3.3.2 --- Effect of Trichloroacetic Acid Concentration --- p.65
Chapter 3.3.3 --- Effect of Hydrochloric Acid Concentration --- p.67
Chapter 3.3.4 --- Effect of Temperature --- p.69
Chapter 3.3.5 --- Effect of Incubation Time --- p.71
Chapter 3.4 --- Study of Blanks --- p.74
Chapter 3.5 --- Construction of Calibration Curves --- p.77
Chapter 3.6 --- Determination of Detection Limit and Sensitivity --- p.84
Chapter 3.7 --- Accuracy and Reproducibility Tests --- p.86
Chapter 3.8 --- Parallel Check --- p.89
Chapter CHAPTER 4 --- CONCLUSION --- p.92
REFERENCES --- p.93
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Guettler, Barbara Elisabeth. "Effect of Thermal and Chemical Treatment of Soy Flour on Soy-Polypropylene Composite Properties." Thesis, 2012. http://hdl.handle.net/10012/6702.
Full textAbstract:
Soy flour (SF), a by-product of the soybean oil extraction processing, was investigated for its application in soy-polypropylene composites for interior automotive applications. The emphasis of this work was the understanding of this new type of filler material and the contribution of its major constituents to its thermal stability and impact properties. For this reason, reference materials were selected to represent the protein (soy protein isolate (SPI)) and carbohydrate (soy hulls (SH)) constituents of the soy flour. Additional materials were also investigated: the residue obtained after the protein removal from the soy flour which was called insoluble soy (IS), and the remaining liquid solution after acid precipitation of the proteins, containing mostly sugars and minerals, which was called soluble sugar extract (SSE).
Two treatments, potassium permanganate and autoclave, were analyzed for their potential to modify the properties of the soy composite materials. An acid treatment with sulfuric acid conducted on soy flour was also considered.
The soy materials were studied by thermogravimetric analysis (TGA) under isothermal (in air) and dynamic (in nitrogen) conditions. SPI had the highest thermal stability and SSE the lowest thermal stability for the early stage of the heating process. Those two materials had the highest amount of residual mass at the end of the dynamic TGA in nitrogen. The two treatments showed minimal effect on the isothermal thermal stability of the soy materials at 200 ??C. A minor improvement was observed for the autoclave treated soy materials.
Fourier transformed infrared (FTIR) spectroscopy indicated that the chemical surface composition differed according to type of the soy materials but no difference could be observed for the treatments within one type of soy material.
Contact angle analysis and surface energy estimation indicated differences of the surface hydrophobicity of the soy materials according to type of material and treatment. The initial water contact angle ranged from 57 ?? for SF to 85 ?? for SH. The rate of water absorption increased dramatically after the autoclave treatment for IS and SPI. Both materials showed the highest increase in the polar surface energy fraction. In general, the major change of the surface energy was associated with change of the polar fraction. After KMnO4 treatment, the polar surface energy of SF, IS and SPI decreased while SH showed a slight increase after KMnO4 treatment. A relationship between protein content and polar surface energy was observed and seen to be more pronounced when high protein containing soy materials were treated with KMnO4 and autoclave. Based on the polar surface energy results, the most suitable soy materials for polypropylene compounding are SPI (KMnO4), SH, and IS (KMnO4) because their polar surface energy are the lowest which should make them more compatible with non-polar polymers such as polypropylene.
The soy materials were compounded as 30 wt-% material loading with an injection moulding grade polypropylene blend for different combinations of soy material treatment and coupling agents. Notched Izod impact and flexural strength as well as flexural modulus estimates indicated that the mechanical properties of the autoclaved SF decreased when compared to untreated soy flour while the potassium permanganate treated SF improved in impact and flexural properties. Combinations of the two treatments and two selected (maleic anhydride grafted polypropylene) coupling agents showed improved impact and flexural properties for the autoclaved soy flour but decreased properties for the potassium permanganate treated soy flour. Scanning electron microscopy of the fractured section, obtained after impact testing of the composite material, revealed different crack propagation mechanisms for the treated SF. Autoclaved SF had a poor interface with large gaps between the material and the polypropylene matrix. After the addition of a maleic anhydride coupling agent to the autoclaved SF and polypropylene formulation, the SF was fully embedded in the polymer matrix. Potassium permanganate treated SF showed partial bonding between the material and the polymer matrix but some of the material showed poor bonding to the matrix. The acid treated SF showed cracks through the dispersed phase and completely broken components that did not bind to the polypropylene matrix.
In conclusion, the two most promising soy materials in terms of impact and flexural properties improvement of soy polypropylene composites were potassium permanganate treated SF and the autoclaved SF combined with maleic anhydride coupling agent formulation.
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"Determination of some minor elements in cement by energy dispersive x-ray fluorescence spectrometry and determination of mercury in water by static cold vapour atomic absorption spectrometry." Chinese University of Hong Kong, 1994. http://library.cuhk.edu.hk/record=b5887279.
Full textAbstract:
by Wong Chi Kin.Thesis (M.Phil.)--Chinese University of Hong Kong, 1994.
Includes bibliographical references (leaves 131-133).
Acknowledgement
Abstract --- p.1
General introduction --- p.4
Part I Determination of Some Minor Elements in Cement by Energy Dispersive X-Ray Fluorescence Spectrometry
Introduction --- p.7
Experimental --- p.14
Results and discussions --- p.18
Part II Determination of Mercury in Water by Static Cold Vapour Atomic Absorption Spectrometry
Introduction --- p.78
Experimental --- p.84
Results and discussions --- p.89
Conclusion --- p.130
References --- p.131
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Riego, Daniela Alejandra. "Análisis de contenido de fósforo en cáncer mamario por microfluorescencia de rayos X." Bachelor's thesis, 2022. http://hdl.handle.net/11086/23640.
Full textAbstract:
Tesis (Lic. en Física)--Universidad Nacional de Córdoba, Facultad de Matemática, Astronomía, Física y Computación, 2022.En el presente trabajo, se ha implementado el Microanálisis por Fluorescencia de Rayos X para el estudio de tejidos neoplásicos. Esta técnica permite un análisis multielemental simultáneo no destructivo, simplificando la tarea laboriosa que implica el análisis elemental tradicional por histoquímica. En particular la micro-XRF permite el monitoreo de fósforo cuya presencia está asociada a microcalcificaciones y al metabolismo tumoral. El fósforo, muestra un incremento significativo en tumores malignos por lo que recientemente se lo ha empezado a emplear como posible biomarcador en modelos de prognosis del cáncer de mama. Estudios preliminares llevados a cabo por el grupo de investigación del presente trabajo han mostrado la viabilidad de la metodología propuesta particularmente aplicada en la determinación de fósforo.
In the present work, the X-Ray Fluorescence Microanalysis (micro-XRF) was implemented for the study of neoplastic tissues. Through this non-destructive technique, precise quantification of phosphorus and calcium in neoplasms of a murine model of breast cancer was achieved with the purpose of being able to distinguish malignant and benign lesions according to the variety of calcified crystals and also using phosphorus content as an indicator of tumor activity and progression. The experimental tasks and data processing processes were further supported by the simulation of radiation transport by Monte Carlo techniques using the open-source program XMI-MSIM.
Fil: Riego, Daniela Alejandra. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía, Física y Computación; Argentina.
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Guettler, Barbara Elisabeth. "Soy-Polypropylene Biocomposites for Automotive Applications." Thesis, 2009. http://hdl.handle.net/10012/4427.
Full textAbstract:
For the automotive sector, plastics play the most important role when designing interior and exterior parts for cars. Currently, most parts are made from petroleum-based plastics but alternatives are needed to replace environmentally harmful materials while providing the appropriate mechanical performance and preferably reduce the cost for the final product.
The objective of this work was to explore the use of soy flakes as natural filler in a composite with polypropylene and to investigate the mechanical properties, water absorption and thermal behaviour. For a better understanding of the filler, the soy flakes were characterized extensively with analytical and microscopic methods.
Two types of soy fillers were investigated, soy flakes, provided by Bunge Inc., with a 48 wt-% protein content and an industrial soy based filler with 44 wt-% protein content and provided by Ford.
The size of the soy flakes after milling was mainly between 50 and 200 µm and below 50 µm for the industrial filler. The aspect ratio for all filler was below 5. The soy flakes were used after milling and subjected to two pre-treatment methods: (1) one hour in a 50 °C pH 9 water solution in a 1 : 9 solid-liquid ratio; (2) one hour in a 50 °C pH 9 1M NaCl solution in a 1 : 9 solid-liquid ratio. A control filler, without pre-treatment was considered. The soy flakes were also compared to an industrial soy based filler provided by Ford (soy flour (Ford)). The thermogravimetric analysis showed an onset of degradation at 170 °C for the treated filler (ISH2O and ISNaCl) and 160 °C for the untreated filler.
The biocomposites formulation consisted of 30 wt-% filler, and polypropylene with/without 0.35 wt-% anti-oxidant Irganox 1010 and with/without the addition of MA-PP as coupling agent. All biocomposites were compounded in a mini-extruder, pressed into bars by injection moulding and tested subsequently.
The mechanical properties of the biocomposites are promising. An increase of the E-modulus was observed when compared to pure polypropylene. The addition of MA-PP as coupling agent increased the yield strength of the biocomposites. When pure polypropylene and the biocomposites were compared no difference could be seen for their yield strength.
The thermal behaviour deduced from differential scanning calorimetry, revealed a similar behaviour for the biocomposites and the pure polypropylene. Only the samples treated in the presence of NaCl and without a coupling agent, appear to have a slightly higher degree of crystallinity. The melt flow index was slightly increased for the biocomposites containing soy flakes pre-treated with NaCl and decreased for biocomposites containing the soy flour.
The water absorption behaviour of the biocomposites was quite similar at the beginning with a slightly lower absorption for the materials with coupling agent. After three months, all samples except the ones treated with water showed a weight loss that can be due to the leaching of the water soluble components in the untreated filler and the NaCl treated filler.
In conclusion, soy flakes represent an attractive filler when used in a polypropylene matrix if an aqueous alkaline pre-treatment is performed. The aqueous alkaline extraction also leads to the recovery of the proteins that can be used in food products while the remaining insoluble material is used for the biocomposites, avoiding the competition with the use of soy for food products...
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Matjie, Ratale Henry. "Sintering and slagging of mineral matter in South African coals during the coal gasification process." Thesis, 2008. http://upetd.up.ac.za/thesis/available/etd-11112008-125913.
Full text