The interest of gaining on-line information related to non-metallic inclusions during the steelmaking process has recently increased due to the development as well as the promising results of the Pulse Distribution Analysis with Optical Emission Spectroscopy method (PDA/OES). Even though, the time from sampling to presented results on inclusions is only about 5-10 minutes, the method has also shown limitations with respect to the determination of some inclusion characteristics. Therefore, a first step was to perform a study on other methods such as the cross-section method (CS) on a polished sample surface, the cross-section after etching method (CSE), the bromine-methanol extraction method (BME), and the electrolytic extraction method (EE). This study focused on the evaluation of these methods with respect to the time consumption for preparation and analysis of a sample, the analyzed volume and the determination of inclusion and cluster characteristics such as size, number, particle size distribution (PSD) and composition. The CS and CSE methods were found to be suitable in the determination of the largest cluster in a sample which can be recommended in order to select proper extraction parameters for further studies. The BME method was considered to be fast with the possibility of analyzing a large volume. However, the used solution is chemically stronger compared to electrolytic extraction solutions, which can affect the results. In most aspects, the EE method was found to be the most stable, reliable and accurate method with some limitations regarding the time aspect. Based on this conclusion, the EE method was selected for a comparative study with the PDA/OES method. Reliably detected size ranges by using the PDA/OES method were defined for two low-alloyed steel grades. These are 2.0-5.7 μm and 1.4-5.7 μm for steel samples taken before and after a Ca-addition during the secondary steelmaking, respectively. Moreover, agreements between the EE and PDA/OES methods were observed in the average size and number of detected inclusions when only inclusions with the size &gt; 2 μm were considered. Also, a theoretical minimum size and a maximum number ofinclusions present in the steel sample, which can be detected by using the PDA/OES method, were estimated. The work continued by successfully applying the EE method to study correlations between inclusions observed in the liquid steel samples and in a clogged nozzle (clogging material). It was found that the average sizes of spherical and non-spherical inclusions observed in the steel corresponded well with those observed in the clogging material. However, there were some differences in the frequencies of these inclusions. This was explained by a possible transformation of the present inclusions due to a reoxidation and a reaction with the nozzle refractory of the steel melt. The results of this study may contribute in the selection of proper process parameters or inclusion characteristics for future studies on the improvement and application of on-line methods. Finally, suggestions on how to present and interpret data obtained by the PDA/OES method during production of stainless steels were given in the present thesis. More specifically, the possibilities of defining operating windows with respect to inclusion composition and the use of a B-factor for Al (the total content of Al in inclusions detected by using the PDA/OES method) during the secondary steelmaking were discussed. In addition, a correlation study between B-factors for Al and numbers of inclusions (dV &gt; 4 μm) obtained by using the PDA/OES method on process samples, and corresponding slivers indices from plate products was performed. The results showed a moderate correlation between these parameters as well as an increase of the slivers index with increased values of the chosen PDA/OES data. This indicates that it could be possible to predict when there is an increased risk of having slivers on the final rolled product at an early stage of the steelmaking process. / <p>QC 20150525</p>

This research aims to understand the organization of activities across a prehispanic urban center at the Formative period site of Tlalancaleca (800 BC- AD 100), located in Puebla, Mexico. This study analyzes soil samples at the central civic-ceremonial complex of Cerro Grande in an attempt to understand the use of space. This work is a part of the larger Proyecto Arqueológico Tlalancaleca, Puebla (PATP), which is focused on understanding the socio-political organization at Tlalancaleca that led to this site of early urbanism. Soil samples from Tlalancaleca are analyzed using three chemical methods to perform a cross-comparison of analytical methods. These three methods are inductively coupled plasma-optical emission spectrometry (ICP-OES), Mehlich 3 soil phosphorus colorimetry, and portable X-ray fluorescence (pXRF) spectrometry. The final results of this soil analysis confirm that the Cerro Grande Complex was an actively used space, with areas maintained for specific uses and areas where activities changed over time. In the comparison of methods, ICP-OES was found to be the most comprehensive, precise, and accurate method to use, while pXRF and Mehlich colorimetry were found to show differing information with regards to available and natural concentrations of the different elements. An analytical examination of phosphorus, strontium, calcium, and barium revealed evidence of construction of monumental buildings, a cache, and possible separate feasting areas, indicating that physical spaces and constructions were likely attached to social and political organizations.

<p>Nanoparticles of iron, cobalt and tungsten oxide were synthesised by photolytic laser assisted chemical vapour deposition (LCVD). An excimer laser (operating at 193 nm) was used as an excitation source. The LCVD process, was monitored <i>in situ</i> by optical emission spectroscopy (OES). The synthesised particles were further analysed using transmission electron spectroscopy (TEM), X-ray diffraction (XRD), high resolution scanning electron microscopy (HRSEM), X-ray fluorescence spectroscopy (XRF), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy.</p><p>Iron and cobalt single crystalline nanoparticles were synthesized using ferrocene and cobaltocene precursors. The diameter of the particles could be tailored by the experimental parameters (e.g., partial pressure and laser power) and were in the range 1 - 50 nm in diameter. In both cases, the particles were covered by a carbon shell, typically 7 nm thick. A thin graphitic layer was observed at the interface metal-carbon. Amorphous carbon was deposited on top of the graphitic carbon. Particle temperature, reaching the boiling point of the respective metal, was observed by OES of the thermal emission during the laser-induced particle formation process (and subsequent heating). Both bcc and fcc Fe phases were formed, both hcp and fcc for the Co phases. Size dependent magnetic properties were observed using superconducting quantum interference device (SQUID) measurements, where super-paramagnetic magnetic domains dominated for <i>d</i> < 10 nm. The iron particles were further processed, whereby the amorphous shell was removed by refluxing in nitric acid. In a subsequent step, the graphitic surface was functionalized by attaching an octyl ester, rendering the particles hydrophobic.</p><p>Tungsten oxides were synthesized from combinations of WF₆/H₂/O₂ as precursors. No particles could be deposited if H₂ was removed from the gas-mixture. The as-deposited oxide nanoparticle film was amorphous. A monoclinic WO₃ particle film could be achieved by annealing the amorphous oxide. Above 400°C, the oxide particles increased in size from ca. 20 nm to 60 nm through coalescence. The gas-sensing properties of the tungsten oxide were tested by conductance measurements using H₂S as analyte. The sensitivity of the amorphous oxide nanoparticle film was found to be superior to that of a crystalline oxide nanoparticle film. </p>

Nanoparticles of iron, cobalt and tungsten oxide were synthesised by photolytic laser assisted chemical vapour deposition (LCVD). An excimer laser (operating at 193 nm) was used as an excitation source. The LCVD process, was monitored in situ by optical emission spectroscopy (OES). The synthesised particles were further analysed using transmission electron spectroscopy (TEM), X-ray diffraction (XRD), high resolution scanning electron microscopy (HRSEM), X-ray fluorescence spectroscopy (XRF), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Iron and cobalt single crystalline nanoparticles were synthesized using ferrocene and cobaltocene precursors. The diameter of the particles could be tailored by the experimental parameters (e.g., partial pressure and laser power) and were in the range 1 - 50 nm in diameter. In both cases, the particles were covered by a carbon shell, typically 7 nm thick. A thin graphitic layer was observed at the interface metal-carbon. Amorphous carbon was deposited on top of the graphitic carbon. Particle temperature, reaching the boiling point of the respective metal, was observed by OES of the thermal emission during the laser-induced particle formation process (and subsequent heating). Both bcc and fcc Fe phases were formed, both hcp and fcc for the Co phases. Size dependent magnetic properties were observed using superconducting quantum interference device (SQUID) measurements, where super-paramagnetic magnetic domains dominated for d &lt; 10 nm. The iron particles were further processed, whereby the amorphous shell was removed by refluxing in nitric acid. In a subsequent step, the graphitic surface was functionalized by attaching an octyl ester, rendering the particles hydrophobic. Tungsten oxides were synthesized from combinations of WF6/H2/O2 as precursors. No particles could be deposited if H2 was removed from the gas-mixture. The as-deposited oxide nanoparticle film was amorphous. A monoclinic WO3 particle film could be achieved by annealing the amorphous oxide. Above 400°C, the oxide particles increased in size from ca. 20 nm to 60 nm through coalescence. The gas-sensing properties of the tungsten oxide were tested by conductance measurements using H2S as analyte. The sensitivity of the amorphous oxide nanoparticle film was found to be superior to that of a crystalline oxide nanoparticle film.

The purpose of this research is to develop a rapid determination method for heavy metals in soil. Using X-ray fluorescence to obtain soil metals decision limit (CC£\) and detection capability (CC£]), to establish the scope of soil metal concentration selection. Then aqua regia digestion digestion and ICP-OES analysis of Pb, Cd, Zn, Ni, Cr, Cu area to check the accuracy of screening. Operating conditions; First, the soil standard samples for the Establishment and assessment of the applicability of the standard. Finally,using of the soil near the control standard establish methods and explore ways to establish the applicability and potential impact. I hope this research can provide a fast, accurate, and sensitivity of soil heavy metal screening, to achieve savings of cost. The results show that the standard reference soil Cu: screening rate was 79.7%, sensitivity was 43.6% and an specificity of 87.7%; reference standard soil Pb: screening rate was 91.5%, a sensitivity of 8.3% specificity 91.5%;reference standard soil Cr:screening rate was 100%, sensitivity was 0%, 100% specificity; reference standard soil Ni: screening rate was 96.1%, sensitivity was 0%, specificity 92.4%; reference standard soil Zn: screening rate was 82.4%, sensitivity was 69.2%, specificity 87.1%; reaching control values of soil Cu: screening rate was 83.0%, sensitivity was 30.8%, specificity of 84.3%. Screening rate and specificity with 80%, the sensitivity poor areas, water was the major disturbance factor.

Glass has been used to make a variety of artifacts including bottles, drinking cups, vessels, window glasses, beads and bracelets. Although occasional glass bracelets were dated back to 2000 BC, large scale manufacture of glass bracelets was encountered in Central Europe in the last centuries of 1000BC. During the excavations of Mezraa H&ouml / y&uuml / k (Birecik-Sanliurfa) in 2000-20002, a number of glass bracelets were unearthed that belongs to 13th century AD. On going excavations of Mersin Yumuktepe also give quite a lot of 11th-12th centuries Byzantine glass bracelets. In this study a group of those bracelets was started to be examined. After technical drawings, color identification had been carried out by using Munsell color chart. Thin sections of some samples of Mezraa H&ouml / y&uuml / k have been prepared and then observed by an optical microscope in Mineral Research and Exploration (MTA). Observation of thin sections showed the amorphous structure of glass with some impurities and gas bubbles. On some samples deteriorated surface layers were present. XRD traces of those layers showed the typical amorphous background of glass in which no crystalline phase is present. Elemental analysis of the samples has been done using ICP-OES method in METU Central Laboratory. In the analysis major (except SiO2), minor and some trace elements were determined. ICP-OES data showed that glass bracelet samples studied are of soda-lime-silica glass. But percentage of Na2O is less than expected from typical composition of soda-lime-silica glass / being 10.5 wt % as average. This might be due to removal of Na ions from the glass network because of leaching under burial conditions. Concentration of Al2O3 in the samples of Mezraa H&ouml / y&uuml / k is almost same. This may be due to the using one type of quartz sand in bracelet production. Color producing elements seem to be Fe, Mn and Cu.

The present study aims to investigate the composition of historical plasters to get information about their material characteristics and their technology. Plaster samples were obtained from four Ankara Citadel houses built in late Ottoman period. In order to determine the raw material characteristics and mineralogical properties of plasters / chemical analyses, optical observation of cross sections, petrographic analyses of thin sections, elemental analyses by ICP-OES, X-ray powder diffraction analyses for the determination of mineral phases, thermogravimetric analyses and FTIR analyses were carried out. Interpretation of all the analytical examination was used to understand the composition and unique character of plaster samples studied. Observation of thin sections revealed more plaster layers than those observed in cross sections. Up to twelve layers could be observed with different colours, such as blue, red, yellow, green, white and brown. Generally, thicknesses of white plaster layers were found to be thicker than the others. In two samples, two black boundaries between plaster layers were identified which could be an indication of the use of asphalt for isolation purposes, like dampness proofing or heat insulation. Soluble salt contents of the plaster samples were in the range 3.04%-9.22%, with an average being 6.62%. The anions identified were Cl-, SO42-. In few samples, PO43-, NO2- and NO3- were found. Binder was found to be lime and gypsum. The amount of binder in terms of total calcium oxide, CaO, was found to be in the range of 33.5-43.6%, with an average being 37.9%. Amount of aggregate was about 62.1% as average. The main minerals identified in plaster samples were calcite and gypsum. Gypsum might be added to increase the strength of the plaster. Beside calcite and gypsum, quartz and pozzolanic activity related mineral, Opal-A, were found in some of the samples. In red plaster layers hematite mineral was also identified. Other colour effective elements were found to be Fe, Sb, Mn, Cu, Cr and Ni. Presence of organic additives was observed but clear identification was not established.

Made available in DSpace on 2016-06-02T20:36:57Z (GMT). No. of bitstreams: 1 DissCCC.pdf: 1000443 bytes, checksum: ddedf64b615b10f0a375f5b68b3da175 (MD5) Previous issue date: 2005-04-07 / Financiadora de Estudos e Projetos / With the objective to attain maximum productivity with small costs, organic and inorganic chemical parameters are used to evaluate and monitoring crops and animals development. Inorganic amounts in agronomic samples have great importance in the production evaluation. Some of elements in those samples could be an indicative of quality, owing to their requirement (Se) or toxicity (As, Sb), even when they are present in µg kg-1 levels, needing a technique with high sensibility for quantification. The aim of this work was the development of a simple system of hydride generation by continuous flow combined with an inductively coupled plasma optical emission spectrometry for simultaneous determination of As, Sb and Se in agronomic samples. The work attained to a gas-liquid separator development, and an experimental planning to established the chemical and instrumental conditions of hydride generation. The HCl, NaBH4 and KI concentrations, such as the R.F. power, carrier gas flow and the viewing height, were evaluated besides the study of a more appropriate sample preparation. Limits of detection of the proposed system were 0.1 µg L-1 for As, Sb and Se and the limits of quantification were 0.3, 0.2 and 0.2 µg L-1 for As, Sb and Se respectively with RSD smaller than 10% and 30 samples per hour of reading speed. In view to observe the accuracy, four different kinds of samples forage and bovine-derived samples (blood, viscera and semen) were spiking with analytes concentration in the µg L-1 level. Recoveries around 77 to 112% were found. The results present the possibility to use the proposed system in agronomic projects developed with the objective to determine essential and toxic analytes in different kinds of feed and animal samples, contributing to evaluation of nutritional demands and the increase of efficiency in the bovine production systems. / Com o objetivo de atingir a maior produtividade com menores custos, parâmetros químicos, orgânicos e inorgânicos, são usados cada vez mais para avaliar e monitorar o desenvolvimento de uma cultura ou espécie. A determinação de constituintes inorgânicos em amostras agronômicas possui grande importância na avaliação da produção. Alguns elementos presentes nessas amostras são indicativos da qualidade devido à essencialidade (Se) ou toxicidade (As, Sb), porém estão presentes na ordem de µg kg-1, necessitando de uma técnica com alta sensibilidade para quantificação. O objetivo deste trabalho foi o desenvolvimento de um sistema simples de geração de hidretos por fluxo contínuo acoplado a um espectrômetro de emissão óptica com plasma induzido para a determinação simultânea de As, Sb e Se em amostras agronômicas. Esse trabalho envolveu o desenvolvimento de uma câmara de separação gás-líquido e um planejamento experimental para a definição das melhores condições químicas e instrumentais da geração de hidretos. Foram estudadas a concentração de HCl, NaBH4 e KI; a potência de radiofreqüência do plasma, o fluxo do gás carregador e a altura de observação do plasma, além do estudo do preparo de amostra mais adequado. Usando as condições otimizadas, foram obtidos limites de detecção de 0,1 µg L-1 para As, Sb e Se e limites de quantificação de 0,3; 0,2 e 0,2 µg L-1 respectivamente para As, Sb e Se com RSD menores que 10% e velocidade de leitura de 30 amostras por hora. Para observar a exatidão do procedimento proposto quatro amostras diferentes - forrageira e amostras bovinas (sangue, víscera e sêmen) - foram dopadas com os analitos na ordem de µg L-1. Recuperações entre 77 e 112% foram encontradas. Espera-se com essa proposta a complementação dos estudos que determinam analitos essenciais e tóxicos em amostras de tecido, fluídos e na alimentação bovina, contribuindo para a avaliação das exigências nutricionais e o aumento da eficiência dos sistemas de produção de bovinos.

102f. / Submitted by Ana Hilda Fonseca (anahilda@ufba.br) on 2013-03-27T17:17:03Z No. of bitstreams: 1 Tese doutorado final Reinaldo Barbour.pdf: 1224301 bytes, checksum: b37e38d9ef21943dba24e8f3638efbcd (MD5) / Approved for entry into archive by Ana Hilda Fonseca(anahilda@ufba.br) on 2013-04-19T13:16:36Z (GMT) No. of bitstreams: 1 Tese doutorado final Reinaldo Barbour.pdf: 1224301 bytes, checksum: b37e38d9ef21943dba24e8f3638efbcd (MD5) / Made available in DSpace on 2013-04-19T13:16:36Z (GMT). No. of bitstreams: 1 Tese doutorado final Reinaldo Barbour.pdf: 1224301 bytes, checksum: b37e38d9ef21943dba24e8f3638efbcd (MD5) Previous issue date: 2011 / CAPES / A determinação de impurezas em cobre eletrolítico, na faixa de μg g-1 e sub μg g-1, é muito importante para caracterizar o cobre de alta pureza (99,99%). As suas propriedades físicas e químicas como maleabilidade, condutividade térmica e elétrica são fundamentais nas aplicações industriais nos setores de eletricidade e eletrônica. Metais e ametais como Ag, As, Bi, Co, Cr, Fe, Mn, Ni, Pb, Sb, Se, Sn,Te e Zn modificam estas propriedades deteriorando sua maleabilidade e condutividade. A espectrometria de massas com plasma indutivamente acoplado (ICP-MS) tem sido muito empregada para a determinação elementar, em amostras industriais, devido às suas características, principalmente as relacionadas com a capacidade multielementar, a rapidez e a alta sensibilidade. As principais desvantagens da técnica são as interferências isobáricas e poliatômicas, além daquelas relacionadas à matriz. Este trabalho teve por objetivo estabelecer um procedimento analítico validado para a determinação de elementos contaminantes por ICP-MS em amostras de cobre eletrolítico, de forma a garantir os limites de quantificação exigidos para a certificação do cobre. O equipamento empregado foi operado nos modos padrão e CCT (célula de colisão que utiliza 1,0% (v/v) NH3 em He balanço) com comutação automática. As amostras e materiais de referência certificados foram digeridos, em triplicata, empregando bloco aquecedor, seguindo o procedimento: 10  1 mg de amostra com 2 mL de HNO3 1:1 (v/v) à 70ºC. A diluição final foi de 5000x, o que contribui para minimização dos efeitos de matriz provenientes da alta concentração dos íons de cobre (~200 ug g-1). Os isótopos selecionados no modo normal de operação do equipamento foram: 55Mn, 59Co, 60Ni, 68Zn, 75As, 107Ag, 118Sn, 121Sb, 128Te, 208Pb e 209Bi. Para o modo com célula de colisão, os isótopos foram: 52Cr, 56Fe, 57Fe, 77Se e 78Se. A faixa linear estudada foi de 0,01 a 2 ng g-1. Os limites de quantificação encontrados (μg g-1 no cobre) foram: Ag (0,05), As (0,2), Bi (0,05), Co (0,1), Cr (0,2), Fe (0,5), Mn (0,2), Ni (0,2), Pb (0,1), Sb (0,2), Se (0,2), Sn (0,2),Te (0,1) e Zn (0,5). A exatidão foi avaliada pela analise dos seguintes materiais de referência certificados: BAM-M381, BAM-M382, BAM-M383, BAM-M384 (Pure Copper, BAM; Federal Institute for Materials Research and Testing) e NIST 495, NIST 496, NIST 457 (National Institute of Standards and Technology) sendo que a maioria das recuperações obtidas foram entre 80 e 120% e os %RSD menores que 10% (Se < 20%). O efeito de matriz foi avaliado através das técnicas de calibração: calibração externa com padrões internos, calibração com adição de analito e calibração com uso dos CRMs e não houve diferença significativa dos resultados. A técnica DC-ARC OES foi empregada para comparação dos resultados. A avaliação dos resultados das amostras reais de bobinas foi feita por meio de ensaios interlaboratoriais e do critério z score. Por este critério, a maioria dos resultados obtidos foram considerados excelentes. Pode-se concluir que o método proposto, empregando ICP-MS, é adequado para determinação multielementar / Salvador

174f. / Submitted by Ana Hilda Fonseca (anahilda@ufba.br) on 2013-04-03T14:55:10Z No. of bitstreams: 1 Tese Cleber.pdf: 3023251 bytes, checksum: 3c19c67227656dc28f623ea371c6e7dd (MD5) / Approved for entry into archive by Ana Hilda Fonseca(anahilda@ufba.br) on 2013-04-23T15:23:58Z (GMT) No. of bitstreams: 1 Tese Cleber.pdf: 3023251 bytes, checksum: 3c19c67227656dc28f623ea371c6e7dd (MD5) / Made available in DSpace on 2013-04-23T15:23:58Z (GMT). No. of bitstreams: 1 Tese Cleber.pdf: 3023251 bytes, checksum: 3c19c67227656dc28f623ea371c6e7dd (MD5) Previous issue date: 2011 / CAPES / Nesta tese é apresentada a aplicação de técnicas quimiométricas na otimização de métodos usando a espectrometria de emissão óptica com plasma indutivamente acoplado (ICP OES) e espectrometria de absorção atômica com chama (F AAS) visando a análise de amostras ambientais. No primeiro trabalho, variáveis como potência de radiofrequência, vazão do gás do plasma, vazão do fluxo de nebulização, vazão do gás auxiliar, vazão da amostra e concentração de ácido nítrico na amostra foram otimizadas através da aplicação de planejamento fatorial completo e Box-Behnken. Parâmetros analíticos como precisão, robustez, sensibilidade e exatidão mostraram-se adequados para determinação de Al, B, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, Pb, Si, Sn, Sr, Ti, Tl, V e Zn em amostras de água subterrânea, água de rio, efluente e solo usando ICP OES. A estratégia de medição e o tempo total de análise também foram otimizados. O novo método foi implantado na rotina do laboratório da CETREL e está proporcionando uma enorme redução no consumo do argônio, em torno de 35 %, gerando uma economia de aproximadamente 320 m3 de argônio anuais, além da redução nos custos associados a outros acessórios do ICP OES. No segundo trabalho, três variáveis de pré-concentração do chumbo (pH, concentração do tampão e vazão da amostra) foram otimizadas empregando planejamento fatorial completo 23. O método é baseado na sorção de Pb(II) em uma minicoluna recheada com uma resina de Amberlite XAD-4 funcionalizada com 4-(5´- bromo-2´-tiazolilazo)orcinol (Br-TAO). O método apresentou limite de quantificação de 1,7 μg L-1, faixa linear de 1,7-200 μg L-1 e fator de enriquecimento de 36, para 25,0 mL de amostra. A exatidão do método foi verificada pela determinação de chumbo em material de referência certificado de água doce NIST 1643d. O método foi aplicado na determinação de chumbo em amostras de água coletadas na cidade de Jequié-BA usando F AAS. Os teores de chumbo variaram de 4,1 a 5,7 μg L-1. As ferramentas quimiométricas utilizadas nos dois trabalhos foram muito eficazes na otimização de variáveis importantes e permitiu um estudo descritivo das variáveis e suas interações. Os dois métodos apresentaram parâmetros analíticos adequados para determinação de metais e metalóides em amostras ambientais / Salvador