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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

Enfoque epidemiológico em dados de tuberculose e brucelose visando a implantação de um sistema informatizado de monitoramento e vigilância

Todeschini, Bernardo January 2010 (has links)
A vigilância epidemiológica é descrita como o conjunto de procedimentos de coleta, processamento e análise de dados utilizado para dar suporte aos processos de tomadas de decisão por parte dos agentes de saúde animal e humana. A crescente atuação de profissionais do setor privado em sanidade animal tem ampliado a vigilância epidemiológica passiva, com geração de montantes significativos de dados. Neste contexto, surge o Programa Nacional de Controle e Erradicação da Brucelose e Tuberculose Animal - PNCEBT que promove, entre suas estratégias, a habilitação de médicos veterinários privados - MVH - para realização de testes diagnóstico dessas enfermidades em bovídeos. Nesta pesquisa, foi realizada uma compilação de todos os dados gerados pelos MVH relacionados ao PNCEBT no ano de 2008 no Rio Grande do Sul, os quais foram posteriormente analisados com distintas técnicas estatísticas, com objetivo de caracterizar o perfil de ocorrência demográfica e espacial destes testes, bem como buscar indicativos de frequência de enfermidades. Foram analisados resultados de 63.226 testes de bovinos e bubalinos realizados em 5.012 estabelecimentos e 332 municípios do estado, devidamente tratados por procedimentos de imputação múltipla e de detecção de valores extremos. Foi possível verificar que os animais de aptidão leiteira representam a maioria dos animais testados, e que motivação econômica, como bonificações, é o principal estímulo para realização dos testes. Os animais de aptidão leiteira apresentaram, ainda, maior frequência em casos positivos para ambas as enfermidades, quando comparados com as demais aptidões. Os animais do sexo feminino apresentaram maior frequência em ambas as enfermidades, com relação aos machos. Foi verificada maior frequência de animais positivos para tuberculose com o avanço da idade, ao passo que a brucelose se revelou mais freqüente em animais entre 48 e 60 meses. A análise espacial demonstra variações entre regiões nos percentuais de animais testados e de positivos em ambas as enfermidades. As maiores frequências de estabelecimentos positivos para tuberculose ocorreram nas mesorregiões metropolitana e centro-oriental do estado, as quais apresentam altas densidades de estabelecimentos por km². Foi constatado ainda que a distância percorrida pelo MVH para realização de testes pode ser fator limitante na ocorrência dos mesmos, sendo que 49,5% dos testes foram realizados em uma distância máxima de 50 km, considerando-se a ida e o retorno. Foi verificado que municípios onde foram realizados testes têm 67,5 vezes mais chance de ter um MVH residente. Foi possível concluir, assim, que o adequado enfoque aos dados de vigilância permite a realização de inferências relevantes, sendo factível a estruturação de sistemas de monitoramento e vigilância - MOSS. Tais sistemas podem incrementar a qualidade e acessibilidade dos dados, permitindo aos gestores públicos e privados a realização de análises customizadas que tragam maior eficiência e eficácia às ações em saúde animal. / Epidemiological surveillance is described as a set of procedures of collecting, processing and data analysis used for supporting the decision making process of animal and human health managers. The growing participation of private sector professionals on animal health issues has been widening the passive epidemiological surveillance, generating significant amounts of data. In this context, the National Program of Animal Brucellosis and Tuberculosis Control and Eradication – PNCEBT, promotes, amongst other strategies, the accreditation of private veterinarians to make diagnosis tests on bovine, increased significantly the amount of data on bovine tuberculosis and brucellosis. In the present research, a compilation of all data from diagnosis tests performed by accredited private veterinarians on behalf of PNCEBT in the state of Rio Grande do Sul in 2008 was made, which was analyzed through distinct statistics techniques, aiming at characterizing the demography and spatial patterns of occurrence, as well as to assess the frequencies of those diseases. Data from 63.226 individual tests performed in 5.012 farms on 332 municipalities were analyzed, after treatment by multiple imputation and outlier values diagnosis. It was possible to conclude that the majority of tests were from dairy related animals; economical reasons, such as bonus programs, were the main motivation for the farmers to perform tests on their properties. Higher frequencies for both diseases were found in dairy cattle, when compared to other purposes animals. Female presented higher frequencies for both diseases when compared to males. It was also observed that the frequency of tuberculosis increased with age, while for brucellosis the frequency was higher between 48 to 60 months-old animals. Spatial analysis evidenced higher frequencies of positive tuberculosis farms in the metropolitana and centro-oriental mesorregions, which had higher farm density per km². It was also verified that the distance by MVH to perform tests might be a limiting factor for them to occur, being 49.5% of the tests performed at maximum round-way distance of 50 km. The municipalities which had tests performed showed 67.5 times more chances of having a resident MVH. It was possible to conclude that an appropriate approach of surveillance data allows the making of relevant inferences, being feasible the establishment of monitoring and surveillance systems - MOSS. These systems could improve data quality and accessibility, allowing public and private managers to perform custom analysis to bring more efficiency and efficacy to animal health programs.
82

Želvušky (Tardigrada) a jejich využití ve výuce / Water Bears (Tardigrada) In Teaching

Gruntová, Zuzana January 2017 (has links)
This thesis is focused on the phylum Tardigrada. The main goal is to implement this topic into the curriculum of primary and secondary education. The thesis is divided in two parts - theoretical and empirical. The theoretical part comprises five basic topics: the general introduction to phylum Tardigrada and other moss fauna; extraction methods; analysis of textbooks for primary and secondary schools; and application of obtained knowledge about phylum Tardigrada in education. In this thesis, water bears are used as model organisms for creating practical suggestions for teaching methods and forms that can be used when implementing this theme into a teaching process. The empirical part presents the results of extensive study focused on the occurrence of Tardigrada in moss from variety of habitats in the Czech Republic and its implication for practical use. Keywords: moss fauna, cryptobiosis, education, teaching methods, research, analysis of textbooks
83

Vegetation of Richards Bay municipal area, KwaZulu-Natal, South Africa, with specific reference to wetlands

Burger, Jeanine 05 August 2009 (has links)
A vegetation survey was conducted at plant community level within the boundaries of Richards Bay Municipal area during 2001 to 2002. Relevés was randomly selected and floristic information was recorded for 310 sample plots and was referenced by GPS. The data were captured in TURBOVEG data base, for vegetation data and classified using the TWINSPAN numerical classification algorithm. Phytosociological tables were compiled using the MAGATAB computerized table management program. Thirteen plant communities were identified, described and characterized by diagnostic and dominant species occurring in them. The study in general showed that vegetation in the Richards Bay Municipal area has deteriorated considerably over the last 30 years. The study indicated that wetland communities occupy a relatively small area and has become relatively degraded within the study area. It is recommended that Richards Bay Town Council plan the Metropolitan Open Space System (MOSS) bringing the ecological areas of importance into consideration and that all new developments in the Richards Bay area be subjected to proper ecological investigation as part of the Environmental Impact Assessment process. Copyright / Dissertation (MSc)--University of Pretoria, 2009. / Plant Science / unrestricted
84

Följer artrikedomen av kärlväxter och svampar varandra på traditionellt hävdade ängar? / Is the species richness in fungi related to the species richness in vascular plants on traditionally managed meadows?

Holmblad Skymberg, Andreas January 2022 (has links)
Loss of biodiversity is a global concern and one of the affected habitats are meadows, where we have a large species richness among fungi and vascular plants who interact in ways that are poorly researched. Many of these meadow species are severely affected by reduced meadow areas which have been converted into farmland, lost their rich flora and mycota because of added fertilizers or have been left unmanaged. The purpose of this study was to investigate if there is any connection between species richness in plants and fungi on meadows, if the meadow age affects species richness, and if environmental variables such as pH, shadowing, moss and soil type has an effect on species richness. During the summer of 2021 plants were counted and in the fall the fungi was counted. Statistical analysis was performed on two different datasets, one with all species counted, one with plant species that have their main habitat on meadows, and fungi commonly known as waxcaps. The result showed a significant connection in species richness between plants and fungi when all species were tested and when a selection of meadow living species was tested. The effect of time showed that the youngest meadow contained the least number of species. Shadowing for plants had a significant negative effect when all species were counted, and all other tests of GLM-models showed significant effects on plants by fungi and vice versa. The results show that there is an interaction between plants and fungi, although we today have a poor knowledge about the actual functionality of these interactions. Other studies have tested low-cost methods to establish meadows in cities and ski slopes, where it is possible to create new suitable habitats for species that have meadows as their main habitat. One of the meadows in this study shows that overgrown meadows can be restored with great results. / Förlust av biodiversitet är ett globalt problem och ett av de habitat som påverkas är ängarna, där det finns en stor artrikedom bland svampar och växter som interagerar med varandra på ett sätt som i dag är dåligt utrett. Många av dessa arter hotas av kraftigt minskande arealer av ängar vilka har gjorts om till åkrar, gödslats så att de har förlorat sin rika flora och funga samt växer igen då de inte längre anses vara användbara. I denna studie undersöks om det går att finna ett samband mellan antalet arter av växter på en äng och antalet arter av svampar samtidigt som påverkan av tiden lokalen har varit en äng testas. Dessutom undersöks vilken påverkan pH, skugga, täckning av mossa och jordtyp kan ha. Under sommaren 2021 inventerades växter och därefter svamparna under hösten. Analysen gjordes i två olika indelningar där alla arter togs med i en och den andra en reducerad indelning där enbart ängsspecifika växter och vaxskivlingar togs med. Datat analyserades statistiskt och resultatet visade att det finns ett signifikant samband mellan antalet arter av växter och antalet arter av svampar både när alla arter räknades in och när de specifikt ängslevande arterna togs med. Effekten av tiden ängarna varit hävdade visade flera signifikanta resultat där tendensen var att den yngsta ängen innehöll minst antal arter. Skuggning visade en signifikant negativ effekt på antalet växtarter när alla arter togs med och övriga statistiska test med GLM visade en signifikant påverkan av växter på svampar och omvänt. Detta resultat visar att det finns interaktioner mellan svampar och växter på ängarna, även om vi idag inte har så god kännedom om hur interaktionen faktiskt fungerar. Det finns undersökningar som visar att det med relativt billiga metoder går att skapa nya ängar både i städer och i skidbackar för att skapa nya lämpliga habitat för ängslevande arter samtidigt som en av ängarna i denna studie visar att vi med rätt vilja kan väcka liv i en äng som under lång tid fått växa igen.
85

Skillnader i artrikedom hos vedlevande mossor och lavar och substratkvalité mellan Säby Västerskogs naturreservat och en närliggande produktionsskog. / Differences in wood-living mosses and lichens species richness and substrate qualities between Säby Västerskog's nature reserve and a nearby managed forest.

Gren, Adrian January 2022 (has links)
Den globala biologiska mångfalden minskar på grund av kraftig mänsklig exploatering av resurser. Ett sådant exempel är diversitetens nedgång i Fennoskandias skogar. Denna studie sökte att undersöka om skogsbruket negativt påverkar mångfalden i en svensk skog i förhållande till dess vedlevande lavar och mossor, med hjälp av träsubstratets kvaliteter som jämförelse och oberoende variabel. 21 vedlevande mossor och lavar var grunden för dessa jämförelser. Studien jämförde två ursprungligen likadana produktionsskogar, där den ena blev ett naturreservat för nästan 100 år sedan. De ligger sydost om Linköping stad, nära BjärkaSäby. Tio 300 m2transekter med slumpmässigt genererade startpunkter och riktningar etablerades i varje skog. Kvantiteten av, deras diameter, deras höjd/längd och deras arttillhörighet för levande och döda träd över en meter i höjd noterades. Nedbrytningsstadier för liggande död ved bredare än 5 centimeter noterades. Ett Wilcoxon-rank-summa-test avslöjade signifikant högre medelvärden av förekomster för vedlevande arter inuti reservatet. Oparade t-tester avslöjade signifikant högre medelvärden för de vedlevande arternasarttäckning och för volymen död ved i reservatet. Pearsons chi-två test avslöjade signifikanta fördelningsskillnader hos levande tallars och lövträdsdiametrar mellan de två områdena men inte mellan fördelningen av nedbrytningsstadier eller hos diametrarna för levande granar. Logistiska regressioner avslöjade att de flesta av de vedlevande arterna med över 10 förekomster i båda områdena över lag hade åtminstone en signifikant korrelation med dess substrats egenskaper. Fynden tyder på att modernt skogsbruk påverkar vedlevande arter negativt, främst på grund av den lilla mängden substrat tillgängligt i produktionsskogen snarare än på grund av substratens variation av egenskaper. / Global biodiversity is declining due to human exploitation, such as seen with its decline within Fennoscandian forests. This study aimed to see if forestry negatively impacts diversity in a Swedish forest in relation to its wood-living lichens and mosses, using the wooden substrate qualities as a point of comparison. 21 saproxylic mosses and lichens formed the basis of these comparisons. The study compared two originally equal production forests, where one became a reserve almost 100 years ago. They are located south-east of Linköping City, near Bjärka-Säby. Ten 300 m2 transects with randomly generated placements and directions were established in each forest. The quantity, diameter, height/length, and species of living and deadtrees over one meter tall were noted. Decay stages for lying dead wood broader than 5 centimeters was noted. A Wilcoxon-rank-sum-test revealed significantly higher meanoccurrences of saproxylic species in the reserve. Unpaired t-tests revealed significantly higher means of saproxylic species coverage and volume of dead wood in the reserve. Pearson’s chi-square test revealed significant distribution differences of living pines and deciduous tree diameters between the two areas but not in the distribution of wood decay stages or in the diameters of living spruces. Logistic regressions revealed that most of the saproxylic specieswith over 10 occurrences in both areas over all had at least one significant correlation with its substrate’s properties. Findings indicate that modern forestry negatively impacts wood-dwelling species mostly due to the small amount of substrate in the managed forest rather than due to their variety
86

Implementation and Evaluation of a TDMA Based Protocol for Wireless Sensor Networks

Fiske, Robert M. January 2010 (has links)
No description available.
87

Biosurveillance des retombées atmosphériques à l'aide de bryophytes : suivi des hydrocarbures aromatiques polycycliques (HAP) à diverses échelles spatio-temporelles / Biomonitoring atmospheric deposition of polycyclic aromatic hydrocarbons (PAHs) with bryophytes at various spatial and temporal scales

Foan, Louise Marie 07 June 2012 (has links)
Les hydrocarbures aromatiques polycycliques (HAP) sont des polluants organiques persistants (POP) émis par les activités humaines suite à la combustion incomplète de la matière organique (industrie, chauffage, trafic routier...). En raison de leur faible taux de dégradation, de leur toxicité, de leur capacité à être transportés sur de longues distances et de leur bioaccumulation dans la matière organique, les HAP font l'objet d'une surveillance atmosphérique (directive cadre européenne 96/62/CE du 27 septembre 1996). Les bryophytes, plus communément appelées mousses, sont utilisées depuis une trentaine d'années pour la biosurveillance de la qualité de l'air. Leurs caractéristiques biologiques font de ces plantes terrestres d'excellents bioaccumulateurs des dépôts de polluants atmosphériques. Cependant, elles ont été peu utilisées pour la biosurveillance des HAP et pour des échelles spatiales et temporelles très limitées. Dans ce contexte, la thèse a pour objectif de valider l'utilisation de bryophytes comme outils pour la biosurveillance des retombées atmosphériques de HAP à différentes échelles spatio-temporelles. La première phase de ce travail a consisté en un développement analytique afin de valider l'analyse des HAP par chromatographie liquide associée à une détection par fluorescence (CLHP-FLD), l'extraction liquide-liquide des HAP contenus dans les dépôts totaux et l'extraction par liquide pressurisé (PLE) des HAP contenus dans les mousses. Cette dernière a été optimisée, grâce à la réalisation d'un plan d'expériences, et a été complétée par des tests de purification par extraction sur phase solide (SPE). Des études de terrain ont ensuite été réalisées afin d'évaluer les tendances temporelles à l'échelle saisonnière, annuelle et historique, ainsi que les tendances spatiales à l'échelle locale et régionale, des teneurs en HAP dans les mousses. Une étude menée sur des mousses d'herbier prélevées dans le Parc Naturel de Bertiz (Navarre, Espagne) entre 1879 et 2007 a permis d'identifier les sources historiques d'émission des HAP. Les bryophytes apparaissent comme de bons « témoins » de la contamination atmosphérique du passé. Une étude annuelle (2010-2011) de biosurveillance active menée à Bertiz a permis ensuite d'observer des tendances saisonnières des teneurs en HAP dans les mousses Hylocomium splendens (Hedw.) Schimp., liées aux variations des émissions atmosphériques et des conditions météorologiques, en particulier des précipitations. De plus, l'étude annuelle a révélé un fractionnement lors de l'accumulation par les mousses des HAP contenus dans les dépôts totaux, qui résulte d'une affinité des HAP pour les dépôts liée à leur solubilité et d'une affinité des HAP pour le végétal liée à leur propriété lipophile (KOW). Ainsi, le suivi des flux atmosphériques de HAP dans les dépôts totaux ne permet pas de prévoir a priori les teneurs de HAP dans les écosystèmes. Enfin, une analyse multivariée de la distribution spatiale des teneurs en HAP dans l'espèce Hypnum cupressiforme Hedw. prélevée en Espagne (Navarre), France (Île-de-France) et Suisse (Plateau Suisse et région de Bâle) a permis de caractériser les sources de contamination atmosphériques des régions étudiées et l'influence de paramètres environnementaux tels que l'altitude et la pluviométrie. / Polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants (POPs) emitted by human activities during incomplete combustion of organic matter (industry, domestic heating, road traffic…). Due to their low degradation rates, toxicity, long-range transport and bioaccumulation in organic matter, PAHs are monitored in the atmosphere (Council Directive 96/62/EC of 27 September 1996). Bryophytes, more commonly called mosses, have been used during the past three decades for biomonitoring air quality. Because of their biological characteristics, these terrestrial plants are excellent bioaccumulators of airborne pollutants. However, few studies concern PAH biomonitoring and they are usually restricted to studies limited in time and space. In this context, the thesis aims to validate bryophytes as tools for biomonitoring atmospheric deposition of PAHs on various space-time scales. The first step of this work consisted in developing the analytical procedures in order to validate PAH analysis by liquid chromatography associated with fluorescence detection (HPLC-FLD), liquid-liquid extraction of PAHs from bulk deposition and pressurized liquid extraction (PLE) of PAHs from mosses. The latter was optimized with a factorial design and was completed by purification tests with solid phase extraction (SPE). Field studies were then carried out to evaluate temporal trends of PAH levels in mosses at seasonal, annual and historical scales, as well as spatial trends, at local and regional scales. A study undertaken on herbarium mosses sampled in Bertiz Natural Park (Navarra, Spain) between 1879 and 2007 leaded to the identification of PAH historical emission sources. Bryophytes appear as excellent “witnesses” of the past atmospheric contamination. An annual biomonitoring study (2010-2011) at Bertiz showed seasonal trends of PAH content in mosses Hylocomium splendens (Hedw.) Schimp., which are related to variations of PAH emissions and weather conditions, particularly precipitations. Moreover, the annual study revealed a fractionation of PAHs while they are transferred from total deposition to the mosses, as the affinity of PAHs for deposition samples was related with their solubility and their affinity for the plant was related to their lipophilic property (KOW). Thus, monitoring PAH fluxes in total deposition does not give an a priori estimation of PAH contents in the ecosystems. Finally, multivariate analysis of the spatial distribution of PAHs in the species Hypnum cupressiforme Hedw. sampled in Spain (Navarra), France (Île-de-France) and Switzerland (Swiss Plateau and Basel area) leaded to the characterization of the atmospheric contamination sources in the different areas and the influence of environmental parameters such as elevation and pluviometry.
88

The evolutionary history of the Antarctic flora

Biersma, Elisabeth Machteld January 2017 (has links)
How long has the extant flora been present in the Antarctic? Glaciological reconstructions propose that most areas in Antarctica were covered by thick ice sheets throughout the Last Glacial Maximum (LGM; ~22-18 kya) as well as previous glaciations, suggesting terrestrial life must have been extremely limited during these periods. In contrast, recent biogeographic and genetic studies support most extant groups of Antarctic terrestrial fauna having survived past glaciations in situ. However, studies on the origin and age of the Antarctic flora remain sparse. Applying population genetic, phylogeographic and divergence time analyses I assessed the global biogeography, origin and age of several abundant Antarctic moss species, including: four Polytrichaceae mosses, characterised by having bipolar distributions, the most common (~45% of species) distribution pattern amongst Antarctic mosses; the globally widespread moss Ceratodon purpureus; the bank-forming moss Chorisodontium aciphyllum, also known for its old sub-fossils in Antarctica and long-term viability from revival experiments; and, lastly, the genus Schistidium, the most species-rich moss genus in Antarctica, including many endemic species. Genetic analyses revealed evidence of long-term (multi-million year) survival of plants in Antarctica (several species of Schistidium, Ceratodon purpureus, and possibly Polytrichum juniperinum). However, evidence for a likely more recent (< 100 ky) arrival of Chorisodontium aciphyllum was also found. Some species revealed multiple separate dispersal events to the Antarctic, suggesting the region may be less isolated for spore-dispersed organisms than previously thought. Evidence for increased genetic diversity in the northern maritime Antarctic compared to other regions point at it including potential refugial areas. Furthermore, genetic patterns revealed geographic features that enable and limit the connectivity of bryophytes globally as well as in Antarctica. This study suggests that, despite the harsh polar climate during glaciation periods, many bryophytes have had a much longer presence in Antarctica than previously thought.
89

Ethnic passing across the Jewish literary diaspora

Katsnelson, Anna 25 January 2012 (has links)
In my dissertation, I examine the works of six writers (George S. Kaufman, Moss Hart, Clarice and Elisa Lispector, Evgenia Ginzburg and Vasilii Aksyonov) who did not explore their Jewish identity in their texts and were subsequently left out of the canons of Jewish literature in their respective countries. My goal is to recalibrate the concept of the Jewish canon from the charged notion of identity to a theory of shared thematic material in which the works of hyphenated Jewish writers will be considered under the category of ‘Jewish American, Brazilian, or Russian’ if they share definite attributes. This was a transnational study showing that similar forces were at work not only in one country, but across continents, affecting the sensibilities of Jewish writers in remarkably similar ways. On a larger scale their de-thematized narratives share thematic tropes and belong to a ‘minor, liminal, marginal narrative,’ a narrative which attempted to work within the scope of the master narratives produced by the hegemonic culture. I have claimed that even though these six writers did not thematize identity in their texts, because of the negative political and social situation for the Jew in the first half of the twentieth century in western civilization, this situation and the writers’ own alterity produced similar and overlapping narratives. / text
90

Advanced analytical methods for platinum group elements:applications in the research of catalyst materials, recycling and environmental issues

Suoranta, T. (Terhi) 02 August 2016 (has links)
Abstract Platinum group elements (PGEs) have a high commercial value and variety of applications in different fields of industry. One of the well-known applications is the use of palladium, platinum and rhodium in the catalytic converters of automobiles to reduce the amount of harmful gases emitted to the environment. Advanced analytical methods are needed to deal with issues related to development of new catalyst materials, recycling of PGEs from spent materials and for monitoring PGE emissions to the environment. In the first part of this study the emphasis was on the catalyst materials. Especially, reliable determination of ruthenium content in catalyst materials required further studies. Consequently, acid digestions in closed vessels using a microwave oven or high pressure asher were compared with a previously reported fusion method. Furthermore, the recovery of PGEs from spent materials is important due to many factors, for example, the high value of these metals, environmental aspects related to their production and possible availability issues in the future. Thus, utilization of microwave-assisted leaching and cloud point extraction (CPE) for the recovery of palladium, platinum, rhodium and ruthenium from catalyst materials was investigated. The second part of this study concentrated on the PGEs in environmental samples and the analytical challenges related to PGE determinations with inductively coupled plasma mass spectrometry (ICP-MS). Due to the use of PGEs in catalytic converters of automobiles, they are emitted to the roadside environment. The use of Pleurozium schreberi, a terrestrial moss, for active biomonitoring of these emissions was evaluated. Advanced analytical methods were needed to perform interference-free determinations of palladium, platinum and rhodium in these samples. Two alternative approaches for interference elimination were studied. Firstly, the interfering elements were removed using CPE as a chemical separation method. Secondly, interferences were eliminated using ammonia as a reaction gas with the novel ICP-MS/MS (inductively coupled plasma tandem mass spectrometry) technique. / Tiivistelmä Platinaryhmän alkuaineita hyödynnetään monissa teknisissä sovelluksissa. Yksi tunnetuimmista on autoliikenteen haitallisten päästöjen vähentäminen käyttäen palladiumia, platinaa ja rodiumia autojen pakokaasukatalysaattoreissa. Luotettavia analyysimenetelmiä tarvitaan esimerkiksi kehitettäessä uusia katalyyttimateriaaleja, kierrätettäessä platinaryhmän alkuaineita käytetyistä materiaaleista tai seurattaessa platinaryhmän alkuaineiden määrää ympäristössä. Tämän tutkimuksen ensimmäinen osa liittyi katalyyttien ruteniumpitoisuuksien määrittämiseen ja platinaryhmän alkuaineiden kierrätykseen katalyyttimateriaaleista. Erityisesti näytteenhajotusvaihe aiheuttaa usein ongelmia ruteniummäärityksissä. Tämän vuoksi tutkimuksessa verrattiin keskenään mikroaaltotekniikalla tai korkeapainetuhkistimella suoritettuja happohajotuksia ja aiemmin raportoidulla sulatemenetelmällä suoritettuja hajotuksia. Mikroaaltoavusteista liuotusta sovellettiin yhdessä samepisteuuton kanssa tutkittaessa katalyyttimateriaalien palladiumin, platinan, rodiumin ja ruteniumin kierrätysmahdollisuuksia. Aihe on ajankohtainen, kun huomioidaan platinaryhmän alkuaineiden korkea hinta, niiden tuotantoon liittyvät ympäristöasiat sekä saatavuuteen liittyvät epävarmuustekijät. Tutkimuksen toisessa osassa keskityttiin ympäristönäytteisiin ja erityisesti niiden ICP-MS -analytiikan (induktiiviplasmamassaspektrometria) haasteisiin. Autojen katalysaattoreista lähtöisin olevia platinaryhmän alkuaineita päätyy ympäristöön lähinnä teiden varsille. Näitä päästöjä arvioitiin aktiivista biomonitorointia käyttäen. Spektraaliset häiriöt vaikeuttivat kerättyjen sammalnäytteiden (Pleurozium schreberi) palladium-, platina- ja rodiumpitoisuuksien määrityksiä. Tämän vuoksi mittauksissa esiintyvien häiriöiden poistossa hyödynnettiin kahta eri lähestymistapaa. Näistä ensimmäisessä häiritsevät alkuaineet poistettiin kemiallisen erotusmenetelmän, samepisteuuton, avulla. Toisessa tavassa häiriöt poistettiin uudella ICP-MS/MS -tekniikalla (induktiiviplasmatandemmassaspektrometria) käyttäen ammoniakkia reaktiokaasuna.

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