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The purpose for this study was to determine the element composition in CoffeeBricks before and after incineration. The difference between element composition in CoffeeBricks (barbecue briquettes made out of spent coffee grounds) and regular barbecue briquettes was also evaluated in this study. Aqua regia digests from the ash residues of CoffeeBricks and the ash residues of regular barbecue briquettes were analyzed with Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES). H2SO4/H2O2 digests from unburned CoffeeBricks and plain spent coffee grounds were also analyzed with ICP-AES in order to evaluate the concentration for selected elements before and after incineration. The chosen elements evaluated in this study had concentrations higher than 0.1 ppm in the measured samples according to the ICP-AES analyses. Element concentrations are presented as mg trace element/g ashes or mg trace element/g sample. The ash residues of regular barbecue briquettes contained higher concentration of Al, Ca, Fe, Mg and S.The ash residues of CoffeeBricks contained higher concentration of B, Cu, Fe, K, Mn, Na and P. One-way ANOVA showed that there were differences in concentration for the elements Ca, K, P, Na and S between the ash residues of the two different types of CoffeeBricks and regular barbecue briquettes for <img src="http://www.diva-portal.org/cgi-bin/mimetex.cgi?%5Calpha" />=0.001. One-way ANOVA also showed differences in concentration for the elements Ca, K, P and Na between the two different types of unburned CoffeeBricks and plain spent coffee grounds for <img src="http://www.diva-portal.org/cgi-bin/mimetex.cgi?%5Calpha" />=0.01.

The characterisation and stability of coal slurries for introduction into an inductively coupled plasma optical emission spectrometer (ICP OES) and the application of slurries in the analysis of coal was investigated. The importance of rheology and the stability of the coal slurries on the analytical results produced by ICP OES was demonstrated. The homogeneity and stability of various coal slurries were characterised by sedimentation tests, scanning electron microscopy (SEM), zeta potential and viscosity measurements. The porosities and surface areas of different South African coals and a mechanism for the adsorption of the dispersants onto the coals were determined using low-temperature nitrogen physisorption studies. The possibility of partially solubulising the coal in N,N-dimethylformamide (DMF) was investigated. SEM indicated that DMF solubulised coal fines and that 0.1% (m/v) Triton X-100 with 10% (v/v) DMFresulted in well dispersed slurries relative to other dispersants (glycerol, PEI and water). Slurry analysis of coarse and ground coal in 0.1% (m/v) Triton X-100, showed that higher emission intensities and better precision was obtained when using ground coal. This was confirmed by lower RSDs (less than 5% for most of the elements analysed) relative to the unground, coarse coal. Glycerol slurries gave higher RSDs (higher than 5% for most of the elements) most of the time, thus negatively influencing the precision of measurement. Physisorption studies indicated that ground coal had up to ten times higher surface areas than coarse coal. The higher surface areas for fine ground coals suggested why they were better dispersed and thus better transported into the plasma, resulting in higher emission signals. Zeta potentials indicated that for all dispersants, the coal particles were well repelled from each other, although SEM pictures indicated better dispersion for 0.1% (m/v) Triton X-100 with 10% (v/v) DMF. It was demonstrated that higher intensities and higher precision could be obtained with well dispersed and stable coal slurries.

A method that involves analysis of bovine liver by slurry nebulization and ICP-OES has been developed. This method permits rapid and accurate determination of Cu, Fe, Mg, Mn and Zn in bovine liver. Aliquots of freeze-dried and powdered bovine liver sample were dispersed in 2.0 M HNO3 and sonicated to homogenize the resulting slurries. Bovine liver samples were also microwave digested or subjected to aqueous extraction for comparison of analytical results. Concentrations of Cu, Fe, Mg, Mn and Zn in aqueous slurries, the digests, and aqueous extracts were determined by the ICP-OES using external calibration curves. A student’s ttest showed that the results obtained using the slurry method were in good agreement at 95 % confidence level (CL) with those of microwave digestion or aqueous extraction techniques, except for Fe. To check the accuracy and precision of the slurry method, a bovine liver CRM was analyzed and good agreement was achieved with the certified values at 95 % CL. The results demonstrate inefficiency of aqueous extraction technique for complete removal of Fe in bovine liver sample.

Dortmund, Univ., Diss., 1999. / Computerdatei im Fernzugriff.

Dortmund, Univ., Diss., 1999. / Computerdatei im Fernzugriff.

Universiẗat, Diss., 2000--Dortmund. / Dateiformat: PDF.

The fabrication process of two-dimensional photonic crystals in an AlGaInP/GaInP multi-quantum-well membrane structure is developed. The process includes high resolution electron-beam lithography, pattern transfer into SiO₂ etch mask by reactive ion etching, pattern transfer through AlGaInP/GaInP layer by inductively coupled plasma (ICP) etching and a selective undercut wet etch to create the freestanding membrane. The chlorine-based ICP etching conditions are optimized to achieve a vertical sidewall. The photonic crystal structures with periods of a=160-480nm are produced. / Singapore-MIT Alliance (SMA)

Made available in DSpace on 2016-08-29T15:35:24Z (GMT). No. of bitstreams: 1 tese_4456_.pdf: 1528315 bytes, checksum: c1bc25c2ff3b6c565f902aa35f03f0b2 (MD5) Previous issue date: 2010-02-26 / Neste trabalho é avaliada a aplicação da técnica de ICP-OES para as determinações de elementos traços ambientalmente possíveis de entrar na cdeia alimentar, em amostras de sedimento de lagoa. Foram investigados os elementos: As, Ba, Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, Se, Sr e Zn e o Al como um elemento majoritário, todos medidos na fração menor que 63µm do sedimento seco a 40ºC, utilizando-se espectrômetro com vista radial, nebulizador V-groove, câmara de nebulização Sturman-Master e sistema de detecção baseado em dispositivo de acoplamento de carga (CCD). Investigou-se a robustez do plasma, velocidade de bombeamento, pressão na câmara de nebulização, potência da radio freqüência, tempo de integração do sinal. Sob condições otimizadas foram obtido os limites de detecção (LD) e os limites de quantificação (LQ). Apesar de As e Se apresentarem os maiores LQs, ainda assim, estes estão abaixo dos valores guias Threshold Effects Levels (TEL) e Probable Effects Levels (PEL), estabelecidos pela Canadian Coucil of Ministers of the Environment (CCME), referência para a resolução do Conselho Nacional de Meio Ambiente (CONAMA 344). A metodologia foi desenvolvida mediante o uso do Material de Referência Certificado (MRC) MESS 3 sedimento marinho, obtendo-se concentrações concordantes com as certificadas (erro relativo <10%), exceto para Al, As e Cd apresentaram erro relativo em torno de 12%. A qualidade dos resultados foi avaliada considerando-se ainda a precisão (RSD<10%), ficando As, Cd, Pb e Se ligeiramente acima do desejado, e medidas de afastamento em ensaios duplicatas que apresentou resultados satisfatórios para todos os elementos traços pesquisados. O sedimento da Lagoa Juara Serra/ES foi caracterizado por determinação da Matéria Orgânica Total (MOT) utilizando as técnicas de mufla a 550ºC e analise termogravimétrica. O resultado de MOT por aquecimento em mufla apresentou resultado duas vezes maior que o obtido por termogravimetria. O resultado de elementos traços e MOT no sedimento, foram correlacionados com a turbidez e o pH da água superficial, por Analise de Componentes Principais (PCA) buscando conhecer as correlações positivas e negativas entre os grupos de parâmetros analisados. Observaram-se quatro grupos de parâmetros positivamente correlacionados: Pb, Ni, Ba, Cu, Mo e turbidez; Zn,Cr e Al; Co, Se, As e pH; Sr, Cd e MOT. O grupo do Cd e do Zn apresentaram correlação negativa, possivelmente devido à contribuição antrópica. O Cd apresentou valores acima do TEL, porém inferior ao PEL.

In this research, electrochemical methods are used to synthesize the inorganic fraction of bone, hydroxyapatite, for application in biological implants and as a calibration material for elemental analysis in human bone. Optimal conditions of electrochemically deposited uniform apatite coatings on stainless steel were investigated. Apatite is a ceramic with many different phases and compositions that have beneficial characteristics for biomedical applications. Of those phases hydroxyapatite (HA) is the most biocompatible and is the primary constituent of the inorganic material in bones. HA coatings on metals and metal alloys have the ability to bridge the growth between human tissues and implant interface, where the metal provides the strength and HA provides the needed bioactivity. The calcium apatites were electrochemically deposited using a modified simulated body fluid adjusted to pH 4-10, for 1-3 hours at varying temperature of 25-65°C while maintaining cathodic potentials of -1.0 to -1.5V. It was observed that the composition and morphology of HA coatings change during deposition by the concentration of counter ions in solution, pH, temperature, applied potential, and post-sintering. The coatings were characterized by powder x-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy. The precipitated powders from the experiment were also characterized, with results showing similarities to biological apatite. There is a need for quantitative elemental analysis of calcified biological matrices such as bone and teeth; however there are no suitable calibration materials commercially available for quantitative analysis. Matrix-matched standards are electrochemically synthesized for LA-ICP-MS analysis of human bone. The synthetic bioapatite is produced via a hydrothermal electrochemical process using a simulated body fluid solution to form hydroxyapatite. Additional bioapatite standards are synthesized containing trace amounts of metals. The x-ray diffraction of the synthesized standards shows an increase in cell volume for the crystal structure from 0.534 to 0.542 nm3 with the substitution of metals into the crystal structure. The analyte concentration and recoveries for the synthesized standards and reference materials were determined by ICP-MS with % RSD below 6.3% and limits of detection below 1.2 ng/mL for trace metals. The electrochemically synthesized bioapatite was also compared to standard reference materials with X-ray diffraction, FTIR, and Raman spectroscopy. Optimum laser ablation parameters were determined for the standards and human bone. The synthesized standards were homogeneous and the reproducibility for the isotope concentrations determined by LA-ICP-MS was between 3-10 % compared to 10-35% for SRM 1486 Bone Meal and SRM 1486 Bone Ash. A quantitative method has been developed for 2D mapping using LA-ICP-MS and the matrix-matched standards of metal-doped biopaptite to characterize metal concentrations in human bone. Laser ablation parameters for the method are refined resulting in concentration (ug/g) contour map measurements for each isotope measured in the human bone. Essential and non-essential metals, Al, Ca, Cu, Fe, Pb, and Zn are quantitatively mapped using these parameters. Limit of detection for the metals in the bone range from 0.001 to 0.08 ug/g. The LA-ICP-MS analysis method developed proves to be a straightforward and simple method for quantitative analysis of human bone.