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Caractérisation mécanique multiaxiale de matériaux polymères, application à un PHA utilisé pour des structures d'emballages alimentaires / Multiaxial mechanical characterization of polymers, application to a PHA used for food packaging structuresGuitton, Erwan 10 December 2014 (has links)
L'étude porte sur la caractérisation des propriétés mécaniques des matériaux polymères et notamment d'un grade d'une famille de matériaux biodégradables et biosourcés : les PolyHydroxyAlcanoates (PHAs). Afin d'étudier ce matériau, un montage expérimental original a été mis en place pour des essais multiaxiaux sur une géométrie unique d'éprouvettes cylindriques. Celui-ci permet d'effectuer des cycles de sollicitations successives et/ou simultanées de traction-compression-torsion. L'objectif est de pouvoir effectuer des chemins complexes, avec changements de direction et cycles au cours d'un même essai, permettant ainsi d'explorer tout le plan déviatoire de déformation avec prise en compte de l'histoire du chargement. De nombreux essais ont été effectués sur le grade de PHA à différentes températures pour développer une base de données expérimentale servant à l'identification d'un modèle de comportement proposé d'Hyperélasto-Visco-Hystérésis (HVH). La méthodologie d'identification des paramètres matériaux est suffisamment simple pour être étendue à une large variété de polymères. Cette identification met particulièrement en évidence les faiblesses et les qualités du modèle. Pour le PHA étudié, la base expérimentale montre ainsi l'insuffisance de la partie visqueuse du modèle, contrairement aux travaux antérieurs utilisant des essais classiques unidirectionnels. Néanmoins, le modèle HVH fournit des réponses précises pour les composantes hyperélastique et hystérétique non-visqueuse dans la gamme [0-100]°C. Cette loi a pour but d'être utilisée pour vérifier la tenue mécanique en statique et en dynamique de structures dans le domaine de l'emballage alimentaire en PHA. / This study deals with the mechanical properties characterization of polymers. One of the studied polymers is part of a biodegradable and biobased family of materials: the PolyHydroxyAlkanoates (PHAs). In order to study its behavior, an original setup has been designed to perform tests with multiaxial loadings on a unique cylindric specimen. It allows to carry out multiple cycles of loadings mixing tensile, compression and torsion. The goal is to be able to perform complex deformation paths with changes in the deformation direction and cycles in a single test. These possibilities allows to scan the deviatoric subspace of deformations with the consideration of the loading history. Many tests has been carried out on the PHA polymer at different temperatures to develop a database used for the identification of a Hyperelasto-Visco-Hysteresis constitutive model. The methodology identification of the mechanical parameters is simple enough to be extend at a large variety of polymers. This identification points out the model weaknesses and qualities. For the studied PHA, the experimental data shows the viscous contribution insufficiency in the constitutive model, unlike previous studies using uniaxial classical tests. Nevertheless, the HVH model gives precise predictions for hyperelastic and non-viscous hysteresis components in the range of [0-100]°C. The constitutive law has been developed in order to check the strength of structures behavior in static and dynamic in the field of food packaging in PHA.
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Dynamický model produkce polyhydroxyalkonoátů termofilní bakterií S. thermodepolymerans / Dynamic Model for Production of Polyhydroxyalkanoates by Thermophilic Bacterium S. thermodepolymeransKřápková, Monika January 2021 (has links)
Tato diplomová práce se zabývá rekonstrukcí dynamického modelu produkce polyhydroxyalkanoátů (PHA) termofilní bakterií Schlegelella thermodepolymerans. První kapitola poskytuje čtenářům krátký úvod do systémové biologie a matematické teorie grafů. Na ni navazuje druhá kapitola zabývající se různými přístupy v dynamickém modelování, včetně běžně používaných nástrojů pro dynamickou analýzu komplexních systémů. Třetí kapitola pak sleduje další pojmy a možnosti týkající se analýzy modelu. Následující kapitola se zaměřuje na metabolomiku a často používané laboratorní techniky a pátá kapitola je pak věnována polyhydroxyalkanoátům, zejména jejich chemické struktuře a vlastnostem. V kapitole šesté je navržen obecný booleovský model pro produkci PHA termofilními bakteriemi. Kapitola sedmá se poté zaměřuje na zdokonalení modelu se zaměřením na S. thermodepolymerans. Výsledný dynamický model je podroben analýze a výsledky jsou diskutovány.
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[pt] HIDROCARBONETOS E NITROAROMÁTICOS NA BAÍA DE GUANABARA: APORTE FLUVIAL E ESTUDO GEOCRONOLÓGICO / [en] HYDROCARBONS AND NITROAROMATIC COMPOUNDS IN GUANABARA BAY: RIVERINE INPUTS AND GEOCHRONOLOGICAL STUDY26 November 2021 (has links)
[pt] A avaliação do aporte continental de hidrocarbonetos para a zona costeira pelos corpos hídricos é de grande importância para melhor compreensão das características regionais quanto à ocupação do solo e do impacto que a urbanização exerce sobre um estuário. As distribuições de hidrocarbonetos alifáticos (n-C12 a n-C40) e hidrocarbonetos policíclicos aromáticos (46 HPAs) foram investigadas no material particulado em suspensão (MPS) e sedimentos ao longo de onze meses em seis dos principais rios e dois canais da bacia da Baía de Guanabara. O ΣHPAs variou de 27,59 a 11.514 ng L-1 no MPS e de 14,60 a 64.961 ng g-1 para as amostras de sedimento. Foram determinadas a taxa de exportação média dos rios dos rios e canais, indo de 0,03 t ano-1 observada para o rio Suruí a 1,87 t ano-1 observada para o rio Iguaçu; a contribuição de HPAs para o sedimento parte norte da baía na e as principais fontes de hidrocarbonetos. Avaliações de tipologia e estatísticas permitiram demonstrar a proporção da contribuição de fontes petrogênicas e pirolíticas nas diferentes regiões e quantificar estas contribuições. A taxa de exportação de HPAs dos cinco principais rios ao norte da baía equivale a 3 t ano-1, representando 30 porcento do aporte total anual de HPAs nesta área da Baía de Guanabara. O estudo geocronológico mostra a evolução histórica do aporte de HPAs apontando para a transição da predominância das fontes de combustão no passado para fontes petrogênicas nos anos recente e mostrou que dentre os NHPAs avaliados, apenas os compostos 2-nitrofluoranteno, 3-nitrofluoranteno e 7-nitrobenzo(a)antraceno foram observados na região noroeste enquanto 2-nitronaftaleno, 5-nitroacenafteno e 2-nitrofluoreno foram observados ao sul da baía, sugerindo a deposição preferencial de subprodutos de reações atmosféricas. Pela primeira vez foi estimada a massa de HPAs depositada ao longo do tempo no sedimento da Baía de Guanabara e realizado o estudo de NHPAs servindo como base para estudos futuros. / [en] The evaluation of the hydrocarbons continental input by end members is of great importance for a better understanding the regional characteristics in terms of land use and the impact that urbanization has on an estuary. Aliphatic (n-C12 to n-C40) and polycyclic aromatic hydrocarbons (46 PAH) were investigated in suspended particulate matter (SPM) and sediments for eleven months in six major rivers and two canals in the basin of Guanabara Bay. The ΣPAH ranged 27.59 to 11,514 ng L-1 for SPM and of 14.60 to 64,961 ng g-1 for the sediment samples. PAH flow rates of the most contaminated rivers and channels ranging of 0,03 t year-1 for Suruí river to 1,87 t year-1 to Iguaçu river; the contribution to the PAH sediment load of the receiving bay, and the main sources of hydrocarbons were determined. Typology and statistical evaluation demonstrated contribution of distinct sources in different regions and allowed quantification of these contributions. Total flow rate for the five major rivers to the bay north amounts to 3 tons year-1 and responds for 30 percent of the total PAH annual input into the northern area of the Guanabara Bay. Geochronological study shows the historical evolution of the PAH contribution pointing to the transition from the predominance of combustion sources in the past to petrogenic sources in recent years and showed that among the nitrated polycyclic aromatic hydrocarbons (NPAHs) evaluated only, 2-nitrofluoranthene, 3-nitrofluoranthene and 7-nitrobenzo(a)anthracene compounds were observed in the region NW while 2-nitronaphthalene, 5-nitroacenaphthene and 2-fluoranthene were observed south of the bay, suggesting preferential deposition of atmospheric reactions byproducts. For the first time PAH mass deposited in the bay sediments has been estimated and conducted the study about NPAHs shall serve as base for future studies.
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[en] PILOT PROJECT: CONCENTRATION PROFILE OF REGULATED AND UNREGULATED POLLUTANTS EMITTED FROM THE COMBUSTION OF BIOFUEL ORIGINATING OF A DIESEL CYCLE ENGINE / [pt] PROJETO PILOTO: PERFIL DA CONCENTRAÇÃO DE POLUENTES REGULAMENTADOS E NÃO REGULAMENTADOS EMITIDOS A PARTIR DA COMBUSTÃO DE BIOCOMBUSTÍVEIS ORIGINÁRIOS DE UM MOTOR DE CICLO DIESELBEATRIZ SILVA AMARAL 14 July 2020 (has links)
[pt] As emissões de combustíveis fósseis derivados do petróleo têm um impacto
significativo no meio ambiente, nas mudanças climáticas, na poluição do ar e
outros. Por isso, existe um grande interesse por fontes alternativas de energia,
principalmente aquelas que podem reduzir as emissões de poluentes atmosféricos.
Este trabalho teve por objetivo avaliar os perfis das concentrações de poluentes
regulamentados (material particulado e CO2) e não regulamentados (benzeno,
tolueno, etilbenzeno, xilenos, HPA, hidrocarbonetos alifáticos, aldeídos e metais)
originados da queima de diferentes combustíveis em um motor estacionário do ciclo
diesel e verificar os possíveis efeitos toxicológicos utilizando células epiteliais
brônquica. Os combustíveis utilizados foram: mistura binária diesel com 5 por cento de
biodiesel (B5), biodiesel de soja (B100), biodiesel de soja aditivado (B100 adt) e
etanol aditivado. Para obter uma maior confiabilidade dos resultados realizou-se a
verificação do método para a determinação de monoaromáticos e aldeídos por meio
de cromatografia gasosa com detector de ionização de chama (CG-DIC) e
cromatografia líquida de alta eficiência (CLAE), respectivamente. O MP foi
determinado por gravimetria, Os HPA associados ao MP foram determinados por
cromatografia gasosa acoplada a espectrometria de massa (CG-EM),
hidrocarbonetos alifáticos (HA) por CG-DIC e metais foram analisados por
espectrometria de massa com plasma indutivamente acoplado (ICP-MS). Os perfis
das concentrações foram avaliados considerando: o tempo de queima de
combustível (15, 30 e 60 min) e, o tempo de armazenamento (7, 14 e 21 dias) a 40
graus Celsius, para avaliar os processos oxidativos que podem ocorrer durante o
armazenamento, especialmente no caso do biodiesel. A operação do motor quando
ele ainda está frio, por exemplo, em 15 minutos, apresentou maior emissão de MP,
benzeno e etilbenzeno para o biodiesel de soja (B100) em comparação com a
mistura de diesel com 5 por cento de biodiesel (B5). O estudo dos perfis das concentrações
dos compostos mono aromáticos, hidrocarbonetos alifáticos e hidrocarbonetos
policíclicos aromáticos (HPA) mostraram resultados semelhantes aos descritos na
literatura, em que o combustível B5 emiti mais poluentes do que o biodiesel. No
entanto, comparando alguns poluentes individualmente, as emissões de benzeno e
etilbenzeno foram maiores para B100 e B100 adt. O B5 apresentou o maior perfil
de concentração para a soma HPA na fase gasosa do que na forma particulada em
períodos de funcionamento do motor mais longos. O tempo de armazenamento
reduziu as emissões de MP em 40 por cento para B100, 20 por cento para B100 adt e 3 por cento para B5. Em relação à concentração de compostos aromáticos, a redução foi de
aproximadamente 60 por cento desses poluentes para B100 e B100 adt. A menor emissão
de poluentes foi durante a queima do etanol aditivado. / [en]
The emissions of fossil fuels derived from oil have a significant impact on the
environment, climate change, air pollution, and others. Therefore, there is great
interest in alternative energy sources, especially those that can reduce emissions of
air pollutants. The aim of this study was the evaluation of concentration profiles of
criteria pollutants, particulate matter (PM) and CO2 and unregulated pollutants (i.e.,
benzene, toluene, ethylbenzene, xylenes, polycyclic aromatic hydrocarbons (PAH),
aliphatic hydrocarbons, aldehyde and metals) originated from burning of different
fuels: The evaluated fuels were the binary mixture of fossil diesel with 5 percent biodiesel
(B5), biodiesel soybean (B100), additivated biodiesel soybean (B100 adt) and
additivated ethanol using a stationary diesel engine cycle, operating at the speed of
1800 rpm and 0 percent load. For a larger reliability of results, the method validation for
determination the monoaromatic and aldehydes by gas chromatography flame
ionization detection (GC-FID) and high-performance liquid chromatography
(HPLC), respectively. PM mass was determinate by gravimetry, PAH associated to
the PM were determined by gas chromatography coupled to mass spectrometry
(GC-MS), aliphatic hydrocarbons were determined by GC-FID, and metals were
determined by inductively coupled plasma mass spectrometry (ICP-MS). The
concentration profiles were evaluated considering: 1) burning time (15, 30, and 60
minutes) and; 2) storage time (7, 14, and 21 days) at 40 Celsius Degrees to evaluate the oxidative
processes that occur during storage, especially for biodiesel. When it is still cold
(i.e., 15 minutes), the operation of the engine showed negative effect on particulate
matter (PM), benzene, and ethylbenzene emissions for B100 compared to B5. In
this study, the concentration profiles of the monoaromatic, aliphatic hydrocarbons,
and PAH showed similar results to those reported in the literature, where B5 fuel
emits more pollutants than pure biodiesel. However, comparing some pollutants
individually, the benzene and ethylbenzene emissions were higher for B100 and
B100 adt. For long engine operation periods, B5 showed the highest concentration
profile for the PAH sum in the gaseous in comparison to PAH sum in the particulate
phase. The storage time reduced the PM emissions in 40 percent (B100), 20 percent (B100
adt), and 3 percent (B5). Regarding the concentration of aromatics, the reduction was
circa 60 percent for B100 and B100 adt. The lowest emission of pollutants was observed
for additived ethanol burning.
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Variabilita zdravotního stavu myší v rámci hybridní zóny Mus musculus musculus a Mus musculus domesticus / Variability in health state of mice in Mus musculus musculus and Mus musculus domesticus hybrid zoneBílková, Barbora January 2014 (has links)
House mouse hybrid zone is a complex of subspecies Mus musculus musculus, Mus musculus domesticus and their hybrids. This hybrid zone is considered as a tension zone, maintained by balance between dispersion of individuals towards the zone center and negative selection against the hybrids. Decreased anti-parasite resistance could be one of selective factors which maintain the hybrid zone. In this thesis, I use hematological methods and skin-swelling test to compare variability in mouse health state within the house mouse hybrid zone. The skin-swelling test is a method measuring pro-inflammatory immune responsiveness. Since the commonly adopted method to perform this test does not allow clear interpretation of the test results, in this thesis I also aim to optimise the test protoco . I found that utilization of concanavalin A (ConA) is more suitable in mice than application of the commonly used phytohemaglutinin (PHA). Assessment of health state of mice by both hematological methods and skin-swelling test consistently indicates increased ability of anti-parasitic resistance in the subspecies M. m. musculus compared to subspecies M. m. domesticus. Hematological examination further shows better health state of hybrid individuals compared to parental subspecies. Our results support hybrid resistance hypothesis....
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Process development for the robust production of polyhydroxyalkanoatesFerré, Anna January 2018 (has links)
Polyhydroxyalkanoates (PHA) are a family of biodegradable polyesters naturally synthesised by some bacteria and archaea. PHA have high industrial value as bioplastics for packaging and biomedical applications. However, their broader use is hindered by high production costs and uncontrolled variation of polymer properties. The extreme halophile Haloferax mediterranei shows bioprocess advantages that can be exploited for the low cost production of the PHA copolymer Poly(3-hydroxbutyrate-co-3-hydroxyvalterate) (PHBV). The focus of this thesis is to identify process variables responsible for the uncontrolled variation of PHA properties in order to progress towards the robust production of PHBV using H. mediterranei. The outcome of the investigation is a novel cultivation strategy for the reliable synthesis of PHBV copolymers with controlled composition and microstructure showing minor differences in material characteristics. Initially, growth kinetics and PHBV synthesis were characterised under nitrogen-excess and nitrogen-limiting conditions in ammonium and for the first time, nitrate. The nitrogen source and concentration influenced PHBV accumulation and variations in polymer composition were observed with ammonium, highlighting the importance of the control of cultivation conditions. Volatile fatty acids (VFA) were found to be a more direct approach to determine PHBV composition and for the first time were used as substrates in H. mediterranei cultures. When the cells were grown in C4:0/C5:0 mixtures, the 3HV fraction in the PHBV was proportional to the percentage of C5:0 in the feed mixture, allowing the synthesis of copolymers with a predefined composition ranging from pure PHB to pure PHV. The cultivation strategy proved effective for the synthesis of HV rich PHBV, which is not easily obtained due to the 3HV precursor toxicity. The polymer microstructure was controlled using different feeding strategies: co-feeding generated random copolymers, while sequential feeding created block and blend copolymers. The synthesis of block copolymers is of interest because the materials show enhanced yield strength and mechanical strength, making such materials more suitable for commodity uses. Bespoke random, block, and blend copolymers with 0â100 mol% 3HV were synthesized and their thermal and mechanical properties studied. Lastly, high temperature cultivation and several surfactants were tested to enhance the production of bespoke PHBV from VFA. PHBV productivity and accumulation was greatly improved in a fed-batch bioreactor fermentation at 37°C with Tween-80 and the maximum PHBV content 58.9% was obtained. The polymers from shake-flasks and from bioreactors showed minor variations in their material properties, demonstrating the scalability and the robustness of the process developed. Further understanding of the different process variables affecting polymer synthesis and composition was gained in this thesis. It is now possible to produce PHBV with controllable composition, microstructure and minor differences in material characteristics. The novel and robust production strategy developed address the bioprocess challenge of minimising the uncontrolled variation of polymer characteristics that is currently hindering the wider use of PHA hence allowing the production of high quality polymers for commodity goods, packaging and biomedical applications.
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Low-Frequency Noise in Si-Based High-Speed Bipolar TransistorsSandén, Martin January 2001 (has links)
No description available.
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Low-Frequency Noise in Si-Based High-Speed Bipolar TransistorsSandén, Martin January 2001 (has links)
No description available.
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Etude de la toxicité cutanée et respiratoire des alcools dans les produits hydro-alcooliques d’hygiène des mains / Study of the cutaneous and respiratory toxicity of alcohols in hand hygiene alcohol-based hand rubsManche, Monique 15 December 2017 (has links)
L’hygiène des mains (HDM) est déterminante dans la prévention du risque infectieux associé aux soins. Les pratiques actuelles privilégient l’utilisation de produits hydro-alcooliques (PHA), généralement formulés avec de l’éthanol, de l’isopropanol et/ou du n-propanol, en présence de co-formulants pour une meilleure acceptabilité cutanée. L’efficacité antimicrobienne sur un temps court, nécessaire en raison des situations fréquentes de pratique d’HDM, est atteinte par des teneurs élevées en alcools pouvant excéder 80 % p/p. Cela soulève la question de la toxicité cutanée et respiratoire associée à l’utilisation des PHA. L’évaluation de la toxicité cutanée basée sur les données publiées et des essais in vitro d’irritation cutanée (OCDE 439) et de phototoxicité (OCDE 432) conclut à l’absence d’irritation cutanée aiguë et de phototoxicité en relation avec l’exposition cutanée à ces alcools, y compris en présence de co-formulants, tels que fournis dans les PHA. Il est ressorti de nos essais le possible manque de spécificité, déjà décrit dans la littérature, des modèles d’épidermes humains reconstitués (RhE) vis-à-vis de certaines substances, qu’il convient de garder à l’esprit dans le cadre de l’évaluation de l’irritation cutanée in vitro. Des investigations complémentaires et une évaluation par l’approche Weight of Evidence peuvent être utiles avant de conclure aux propriétés irritantes d’un item d’essai. En termes de génotoxicité, une différence entre les alcools ressort de la revue bibliographique, avec des propriétés génotoxiques décrites uniquement pour l’éthanol. Dans une certaine mesure, nos essais ont confirmé une différence de profil. L’isopropanol et le n-propanol testés dans une batterie de tests in vitro permettant d’appréhender les différents mécanismes génotoxiques (test d’Ames et test du micronoyau (MN) sur cellules humaines p53 compétentes : cellules lymphoblastoïdes TK6 et cellules pulmonaires NCI H292) ont donné des résultats négatifs, y compris lorsqu’ils étaient formulés avec des co-formulants, ou administrés sous forme de vapeurs sur les cellules NCI H292 cultivées en interface air-liquide (IAL). Pour l’éthanol, la réalisation de la même batterie de tests a conduit à des résultats équivoques uniquement dans le test du MN sur cellules TK6 avec l’éthanol seul. Un test du MN supplémentaire sur cellules TK6 en co-culture avec un RhE mimant la barrière cutanée a donné des résultats négatifs. Par ailleurs, aucune exposition systémique significative aux alcools induite par les pratiques d’HDM ne ressort des études publiées chez l’homme, avec des taux indiscernables des valeurs endogènes existantes pour l’éthanol et l’isopropanol. L’ensemble de ces données est en faveur de l’absence de risque génotoxique systémique consécutif à l’utilisation des PHA, et de l’absence de génotoxicité pulmonaire locale liée à l’exposition aux vapeurs d’alcools. En conclusion, en situation d’utilisation des PHA pour l’HDM, aucun risque pour la santé humaine en termes d’irritation cutanée aiguë, de phototoxicité et de génotoxicité ne ressort de ce travail de recherche. / Hand hygiene (HH) is a key factor in preventing healthcare-associated infections. Current practices favor the use of alcohol-based hand rubs (AbHR), generally formulated with ethanol, propan-2-ol and/or propan-1-ol, in the presence of co-formulants for a better skin acceptability. The antimicrobial efficiency within a short time, essential because of the frequent situations of HH practice, is achieved by high levels of alcohols which can exceed 80% w/w. This raises the question of dermal and respiratory toxicity associated with the use of AbHR. The assessment of dermal toxicity based on published data and in vitro skin irritation (OECD 439) and phototoxicity tests (OECD 432) conclude to non acute dermal irritation and phototoxicity risk linked to dermal exposure to these alcohols, even in the presence of co-formulants, as provided in the AbHR. We encountered in our trials the possible lack of specificity, already described in the literature, of the reconstructed human epidermis (RhE) models for some substances, which should be kept in mind in the context of the evaluation of skin irritation in vitro. Additional investigations and an assessment using the Weight of Evidence approach may be useful before concluding the irritant properties of a test item. In terms of genotoxicity, a difference between the alcohols emerges from the bibliographic review, with genotoxic properties described only for ethanol. To a certain extent, our tests confirmed a difference in profile. Propan-2-ol and propan-1-ol tested in a battery of in vitro tests to explore the various genotoxic mechanisms (Ames test and micronucleus test (MN) on p53 competent human cells: lymphoblastoid cells TK6 and pulmonary cells NCI H292) gave negative results, even in the presence of co-formulants, or administered as vapors on air-liquid interface (ALI) NCI H292 cells. For ethanol, the same battery of tests gave equivocal results only in the MN test on TK6 cells with ethanol alone. An additional MN test on TK6 cells co-cultured with a RhE mimicking the existing skin barrier gave negative results. In addition, no significant systemic exposure to alcohols induced by HH practices is apparent from published studies in humans, with indiscernible levels of existing endogenous values for ethanol and isopropanol. All of these data support the absence of an increased systemic genotoxic risk resulting from the use of AbHR and the absence of local pulmonary genotoxicity due to exposure to alcohol vapors. In conclusion, during AbHR use for HH, no risk to human health in terms of acute skin irritation, phototoxicity and genotoxicity is apparent from this research.
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Extração em ponto nuvem com derivatização do surfactante: uma alternativa para a determinação de hidrocarbonetos policíclicos aromáticos em águas naturais por cromatografia gasosaRocha, Sarah Adriana do Nascimento 10 1900 (has links)
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Tese_Sarah_Rocha_LSGT.pdf: 3229640 bytes, checksum: af1acce9c5d43271ea20530b0fd1f510 (MD5) / Um método de extração em ponto nuvem de hidrocarbonetos policíclicos
aromáticos foi desenvolvido, utilizando tensoativos octilfenol polietoxilados com
derivatização do coacervato, como etapa que antecede a detecção por
cromatografia a gás acoplada à espectrometria de massa. Foi realizado um
estudo da influência da presença de aditivos na redução da temperatura de
ponto nuvem do OPEO30 e do OPEO35, surfactantes com temperaturas de
ponto nuvem superiores a 100 oC, através adição de sais, álcoois, OPEO7.5 e
misturas de sais e álcoois. Observou-se em todos os casos diminuição da
temperatura, sendo o sulfato de sódio o aditivo que resultou maior redução da
temperatura. Selecionou-se o OPEO30 para as demais etapas do trabalho.
Fez-se a otimização das condições da reação de derivatização do coacervato
por meio de planejamento fatorial 23, utilizando-se a resposta global para
avaliar os resultados. Selecionou-se as condições do ponto central do
planejamento fatorial, ou seja, 125 L de BSTFA, 100 L de piridina e banho de
água à 70 oC por 45 min, para a derivatização de 30 L de fase rica em
surfactante. O procedimento de ponto nuvem foi otimizado, sendo avaliadas as
variáveis concentração de surfactante, temperatura e tempo de banho de água,
sendo proposta a seguinte metodologia: 1,0 mL de OPEO30 10% m v-1, 10,0
mL de amostra, 1,25 g de sulfato de sódio anidro, banho de água à 70 oC por
10 min, centrifugação à 3000 rpm por cinco min. O método mostrou-se seletivo,
sendo observado efeito de matriz intenso, o qual foi corrigido. Os limites de
quantificação obtidos estão entre 39 e 176 ng L-1. O método proposto também
foi comparado com o método USEPA 3510C, estando as concentrações
obtidas, quando analisada uma amostra real de água subterrânea, bem
próximas, com recuperações variando entre 90,0 e 97,5 %. O método proposto
foi aplicado a amostras de água subterrânea coletadas em poços localizados
em postos de revenda de combustíveis. Em todas as amostras foram
detectados HPA. / A method for cloud point extraction of polycyclic aromatic hydrocarbons was
developed using surfactants octylphenol polyethoxylated with the coacervate
derivatization as step prior to gas chromatography-mass spectrometry
detection. An influence of additives study on the reduction of cloud point
temperature OPEO30 and OPEO35, surfactants with cloud point temperatures
above 100 ° C, was conducted, by addition of salts, alcohols, and mixtures
OPEO7.5 salts and alcohols. It was observed in all cases cloud point reduction
and sodium sulfate was the additive that result in a most effective. The OPEO30
was selected for others work steps. The factorial design 23 was used to
optimize the reaction of derivatization, using the global response to evaluate the
results. Were selected the central point experimental design condition, 125 L
of BSTFA, 100 L of pyridine and water bath at 70 oC for 45 min for 30 L of
surfactant-rich phase derivatization. The cloud point extraction procedure was
optimized and surfactant concentration, heating bath temperature and time
variables, were evaluated. Was proposed the following method: 1,0 mL of
OPEO30 10% v m-1 solution, 10,0 mL of sample, 1,25 g of anhydrous sodium
sulfate, water bath at 70 °C for 10 min. The centrifugation was performed at
3000 rpm for five min, removing the aqueous layer after each centrifugation
step. A 30L coacervate aliquot was withdrawn, and performed derivatization
and subsequent GC-MS analysis. The method was validated. The method was
selective, an intense matrix effect was observed and was corrected. The
quantification limits obtained were between 39 and 176 ng L-1.
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