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Delar av en grav och glimtar av en tid : Om yngre romersk järnålder, Tuna i Badelunda i Västmanland och personen i grav X / Parts of a Grave and Glimpses of a Time : A discussion of the Late Roman Iron Age, Tuna in Badelunda in Västmanland and the person in Grave XFernstål, Lotta January 2004 (has links)
Grave X was found in 1952 during construction work in Tuna in Badelunda parish, in the province of Västmanland. Objects from this 3rd Century grave were dispersed and the stone grave covering and cist-like wooden burial chamber were cut almost in half as a result of the construction work that unearthed it. The purpose of this dissertation is to create a better understanding of Tuna in Badelunda and to place Grave X and the person buried there in context. Due to my interest in Grave X and the person in this grave, the scope of the study is limited to Tuna during the Late Roman Iron Age. What kind of place may Tuna in Badelunda have been during that time? Which kinds of knowledge may the person in Grave X have possessed and what roles may this person have had in local society? How may this person have acted in Tuna in Badelunda in particular? Why was this person buried in the specific type of structure that was Grave X? To answer these questions, ancient monuments and phenomena in the Tuna area, objects from the grave and construction details of the grave are discussed. Specifically, I examine the name Tuna, stone enclosures, hillforts of Bejby borg-character and travel routes, beads, golden rings in the shape of snakes, vessels and serving utensils, and the stone grave covering and cist-like chamber. Since Grave X was partly ruined when discovered, comparisons are made to about 20 similar graves from other parts of Scandinavia in order to get an idea of what may have been lost from Grave X. A performative-constructive gender perspective is of importance in this dissertation, as well as the concept of creolization. The kinds of knowledge and the societal roles the person in Grave X may have had can be summarized in five categories or contexts of action: production within the (social-political) economy of the farm, ritual performances, physical communication, textile production, and oral performances with the telling of stories and relating of memories. Possible personal strategies in relation to the activities the person in question was involved in are seen as important. One way this dissertation takes up this subject is through the discussion of the role the person may have had in greetings and farewells in the yard of the farm (Sw. tun, gårdsplan). Greetings and farewells were probably of importance, and Tuna is discussed as a crossroads. This means that although a local perspective is advocated in this dissertation, Tuna may not be seen as an isolated community, but rather as a small place that to a great extent partook in the larger world. This can also be seen in Grave X; when the person in this grave was buried, the living made choices that both expressed local traditions and made reference to far-away places. In contrast to the surrounding graves, the person in Grave X was not cremated. One of many possible reasons may have been a desire to emphasize the person’s personality and gender as well as roles in society. / <p>Auktoriserad namnform i LIBRIS: Fernstål, Charlotte, 1974-</p>
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Caractérisation des courants de fuite à l'échelle nanométrique dans les couches ultra-minces d'oxydes pour la microélectroniqueHourani, Wael 09 November 2011 (has links) (PDF)
La miniaturisation de la structure de transistor MOS a conduit à l'amincissement de l'oxyde de grille. Ainsi, la dégradation et le claquage sous contrainte électrique est devenu l'un des problèmes de fiabilité les plus importants des couches minces d'oxydes. L'utilisation de techniques de caractérisation permettant de mesurer les courants de fuite avec une résolution spatiale nanométrique a montré que le phénomène de claquage des oxydes est un phénomène très localisé. Le diamètre des "points chauds", des endroits où le courant de fuite est très élevé pour une tension appliquée continue, peut-être de quelques nanomètres uniquement. Ceci illustre pourquoi les méthodes de caractérisation avec une résolution spatiale à l'échelle nanométrique peuvent fournir des informations supplémentaires par rapport à la caractérisation classique macroscopique. Il y a deux instruments, dérivés de la microscopie à force atomique (AFM) qui peuvent être utilisés pour faire ce travail, soit le Tunneling Atomic Force Microscope (TUNA) ou le Conductive Atomic Force Microscope (C-AFM). Le mode TUNA qui est utilisé dans notre travail est capable de mesurer des courants très faibles variant entre 60 fA et 100 pA. Notre travail peut être divisé en deux thèmes principaux: - La caractérisation électrique des couches minces d'oxydes high-k (LaAlO3 et Gd2O3) à l'échelle nanométrique en utilisant le Dimension Veeco 3100 où nous avons montré que la différence de leurs techniques d'élaboration influe largement sur le comportement électrique de ces oxydes. - Les caractérisations électriques et physiques à l'échelle nanométrique des couches minces d'oxydes thermiques SiO2 sous différentes atmosphères, c.à.d. dans l'air et sous vide (≈ 10-6 mbar) en utilisant le microscope Veeco E-Scope. L'influence de l'atmosphère a été bien étudiée, où nous avons montré que les phénomènes de claquage des couches minces d'oxydes peuvent être fortement réduits sous vide surtout en l'absence du ménisque d'eau sur la surface de l'oxyde pendant les expériences. En utilisant les plusieurs modes de l'AFM, il a été démontré que l'existence de bosses anormales (hillocks) sur la surface de l'oxyde après l'application d'une tension électrique est une combinaison de deux phénomènes: la modification morphologique réelle de la surface de l'oxyde et la force électrostatique entre les charges piégées dans le volume de l'oxyde et la pointe de l'AFM. Selon les images du courant obtenues par AFM en mode TUNA, deux phénomènes physiques pour la création de ces hillocks ont été proposés: le premier est l'effet électro-thermique et la seconde est l'oxydation du substrat Si à l'interface Si/oxyde.
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Three-dimensional tide and surge modelling and layered particle tracking techniques applied to Southern Australian coastal seasGrzechnik, Marcus Paul January 2000 (has links)
This thesis reports the development, testing, and application of computer programs for simulating Lagrangian-Stochastic particle dispersion in coastal seas, with particular application to tide and storm induced dispersion in South Australian seas. The three-dimensional tidal equations are briefly discussed for the two types of surge models used, and finite-difference methods for numerically solving these equations are considered. Different methods of simulating flows at open sea boundaries are investigated. The method of particle tracking and the development of the particle tracking model is also described. Various tests are conducted to investigate both the advective and diffusive aspects of dispersion, and a number of scenarios for the simulation of open (ocean) and closed (coastal) boundaries are considered. Various aspects of the particle tracking routine are given specific characteristics according to the nature of the particle being considered. Application of the tide and storm surge model to the Great Australian Bight is described. This uses spherical polar co-ordinates to account for the curvature of the earth, and an oblique boundary element to increase accuracy of the coastline representation. The effect of a low pressure system moving from west to east across the Bight and the resulting significant observed surge at Thevenard during the storm of April 1996 is simulated. This storm resulted in a significant number of deaths in aquaculture farms containing southern bluefin tuna (Thunnas maccoyii) within the Boston Bay region to the extreme east of the Bight due to the agitation of almost neutrally buoyant organic sediments at the sea floor. The effects of this storm are further considered using a Cartesian co-ordinate fine-grid local model of Boston Bay, in Spencer Gulf, South Australia, where both tidal and storm (wind and outside surge) induced flows are simulated. The dispersion of suspended neutrally buoyant sediment throughout the region is considered, and compared with the mortalities of tuna at various farms within the region. Tidal and storm induced currents in the Gulf St. Vincent region, South Australia, have also been modelled using Cartesian co-ordinates. Detailed consideration has been given to the modelling of tides, winds, atmospheric pressures and outside surges from the two open boundaries in Investigator Strait and Backstairs Passage. The information obtained has enabled the modelling of a number of storm surge scenarios. Further to this, various simulations of the dispersion of the larvae of the western king prawn (Penaeus latisulcatus) have been driven using the storm surge model developed. These incorporate currents near the surface and the sea floor, as well as the consideration of changes in behaviour during the life history of the larvae. / Thesis (Ph.D.)--Engineering, Computer and Mathematical Sciences, 2000.
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Ecologia e conservação do tubarão galha-branca oceânico (carcharhinus longimanus, poey 1861)TOLOTTI, Mariana Travassos 19 February 2016 (has links)
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Previous issue date: 2016-02-19 / CAPEs / O objetivo principal da presente tese consistiu em agregar informações ao
conhecimento sobre o tubarão galha-branca oceânico (Carcharhinus longimanus),
principalmente no que se refere à sua distribuição, índices de abundância e
preferências de habitat. Apesar de ser uma espécie muito capturada na pesca
oceânica de atuns afins, informações acerca destes aspectos ecológicos são
escassas e até mesmo ausentes na literatura relacionada à espécie. A tese é
apresentada como um conjunto de capítulos autônomos, representando artigos
científicos individuais. No primeiro capítulo-artigo foram discutidos os possíveis
efeitos de medidas de manejo restritivas, implementadas recentemente por
Organizações Regionais da Pesca Atuneira e que incluem algumas espécies de
tubarões oceânicos. Medidas restritivas isoladas terão pouco impacto na redução
da mortalidade de tubarões oceânicos. Um conjunto de medidas mitigadoras
integradas será mais eficaz na conservação e recuperação das populações dessas
espécies. No segundo capítulo-artigo foram analisados dados de captura e
esforço de 14.835 lançamentos de espinhel pelágico realizados por embarcações
arrendadas da frota atuneira brasileira, nos anos de 2004 a 2010. A CPUE nominal
exibiu uma tendência de aumento gradual ao longo dos anos, variando de 0,04
em 2004 para 0,15 em 2010. A CPUE foi padronizada através de uma abordagem
delta-GLM, entretanto, o índice de abundância padronizado não diferiu
significativamente da CPUE nominal. Os modelos indicaram que as capturas de
tubarões galha-branca são maiores para a estratégia de pesca espanhola, que se
caracteriza pela utilização de anzóis em profundidades mais rasas. No terceiro
capítulo-artigo, a interação entre tubarões galha-branca e a pesca de rede de
cerco nos Oceanos Atlântico e Índico foi analisada, com o objetivo de investigar o
potencial da utilização do banco de dados dessa pescaria para derivar índices de
abundância e determinar tendências populacionais para a espécie. Dados de
observadores de bordo da frota francesa combinados com dados históricos da
União Soviética foram utilizados na análise. A série temporal combinada incluiu os
anos entre 1986 e 2014. No Oceano Atlântico não foi possível determinar uma
tendência populacional, uma vez que o índice de ocorrência foi muito baixo e não
variou significativamente com o tempo. No Oceano Índico foi observada uma
mudança bem-marcada no índice de ocorrência, oscilando em torno de 20% entre meados dos anos 80 e 90 e caindo para menos de 10% a partir de 2005. No
quarto capítulo-artigo, a vulnerabilidade do tubarão galha-branca à pesca de
espinhel pelágico foi avaliada utilizando dados dependentes e independentes da
pesca. Os dados dependentes incluíram informações de diários de bordo (1999-
2011) e observadores embarcados (2004 a 2010), num total de 65.277
lançamentos de espinhel. Os dados independentes foram obtidos a partir de 8
tubarões marcados com marcas do tipo “pop-up satellite archival tag” na área
onde a frota de espinhel operou. Locais de marcação e desprendimento das
marcas foram relativamente próximos uns dos outros. Entretanto, os indivíduos
marcados tenderam a viajar longas distâncias antes de retornar para a área de
marcação. Foi observado um certo grau de filopatria à área. “Hotspots” de alta
utilização dos tubarões marcados correspondeu à área sob forte pressão
pesqueira. Todos os tubarões exibiram uma forte preferência por águas quentes
e rasas da camada de mistura, gastando, em média, mais de 70% do tempo acima
da termoclina e 95% acima de 120 m. Esse resultado justifica a maior
capturabilidade da espécie em espinheis mais rasos. No quinto e último capítuloartigo,
os movimentos verticais dos tubarões marcados foram analisados em
detalhe. Apesar da distribuição vertical restrita, os dados indicaram que o tubarão
galha-branca apresenta padrões de movimento complexos, incluindo padrões de
migrações circadianas distintos e mergulhos profundos. O padrão circadiano mais
frequentemente observado é caracterizado de um deslocamento à superfície
durante o nascer do sol e uma tendência a permanecer em profundidades mais
baixas durante o dia. Os movimentos verticais também foram influenciados pela
temperatura da superfície do mar, o que pode indicar a ocorrência de
termoregulação para espécie. A integração dos resultados de cada capítuloartigo
proporcionou boas perspectivas para o desenvolvimento de medidas de
mitigação. A evidência em relação à preferência do tubarão galha-branca por
águas quentes e rasas é sólida, indicando que a remoção dos anzóis rasos do
espinhel pode ser proposta para reduzir a captura incidental da espécie. O fato
de variações na CPUE já terem sido observadas, sugere que esta pode ser uma
medida eficaz. O comportamento filopátrico observado para o OCS também
indica que a espécie pode se beneficiar com a criação de áreas marinhas
protegidas. / The ultimate goal of this thesis was to generate knowledge regarding the ecology
of the oceanic whitetip shark (Carcharhinus longimanus) and contribute for an
ecosystem-based fishery management. The work focuses on the interactions
between tuna fisheries and the species and its habitat preferences. Despite being
frequently caught on high-sea fisheries, there are wide knowledge gaps regarding
the ecology of the oceanic whitetip shark. The thesis is presented as a set of selfcontained
standalone chapters, constructed as individual research articles. The
first article-chapter provides a discussion concerning pelagic sharks and the
recent species-specific banning measures implemented by Regional Fishery
Management Organizations (RFMOs) in charge of tuna fisheries. It is unlikely that
banning measures alone can reduce the high level of fishing mortality and recover
pelagic shark’s depleted populations. Managers should be fully aware that the
development and implementation of mitigation measures are critical for a more
effective conservation strategy. In the second article-chapter, catch and effort data
from 14,835 longline sets conducted by foreign tuna longline vessels chartered
by Brazil, from 2004 to 2010, were analyzed. The nominal catch per unit of effort
(CPUE) exhibited a gradual increase, varying from 0.04 sharks/1000 hooks in
2004 to 0.15 in 2010. A CPUE standardization was performed using a delta-GLM
approach, but the standardized index of abundance did not differ significantly
from the nominal CPUE. The models indicated that the catches of oceanic whitetip
sharks are higher for the Spanish fishing strategy, which is characterized by the
deployment of hooks at shallower depths. In the third article-chapter, the
interaction between oceanic whitetip sharks and the purse seine fishery in the
eastern Atlantic and western Indian oceans was analyzed, in order to investigate
the potential of using this fishery’s database to derive abundance indexes and
determine population trends for the species. Observer data from the French purse
seine fleet combined with a historic database from the Soviet Union were used in
the analyses. The combined time series spanned from 1986 to 2014. The
occurrence index was very low for Atlantic Ocean and no marked temporal trend
was observed. For the Indian Ocean a well-marked change on the occurrence
index was observed, fluctuating around 20% from mid 80’s to mid 90’s and
dropping to less than 10% as from 2005. In the fourth article-chapter, a combination of fisheries dependent and independent data was used to assess the
vulnerability of the oceanic whitetip shark to pelagic longline fisheries. Fisheries
dependent data included information from logbooks (from 1999 to 2011) and onboard
observers (2004 to 2010), totaling 65,277 pelagic longline sets. Fisheries
independent data were obtained from 8 oceanic whitetip sharks tagged with popup
satellite archival tags in the area where longline fleet operated. Tagging and
pop-up sites were relatively close to each other, although individuals tended to
travel long distances before returning to the tagging area. Some degree of
philopatry was observed. High utilization hotspots of tagged sharks fell inside the
area under strongest fishing pressure. All sharks exhibited a strong preference for
the warm and shallow waters of the mixed layer, spending on average more than
70% of the time above the thermocline and 95% above 120 m. This result explains
the higher catchability of the species on shallow longline gear. In the fifth and last
article-chapter, the vertical movements of tagged oceanic whitetip sharks were
analyzed in detail. Despite its restricted vertical distribution, the analyses reveled
that oceanic whitetips perform complex movement patterns, including distinct
diel patterns and deep diving behavior. A correlation between vertical
movements and sea surface temperature was also observed, suggesting the
occurrence of thermoregulation for the species. The combined results of each
article-chapter have provided good insights towards the development of
mitigation measures. The evidence regarding oceanic whitetip shark’s preference
for warm and shallow waters is solid and this information suggests that the
removal of the shallow hooks from the longline gear could be proposed as a
technique to reduce OCS bycatch. The fact that CPUE variations were already
observed suggests that this might be an effective measure. The philopatric
behavior observed for the OCS also indicates that the species could benefit from
time-area closure measures.
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Medborgardialog i Rasbobygden : En fallstudie i Uppsala kommunÖstlund, Camilla January 2006 (has links)
ABSTRACT Citizendialogue in the District of Rasbo A Case Study in the Municipality of Uppsala Author: Camilla Östlund Supervisor: Stig Montin The essay is written inside the scope of Örebro Universitys evaluation of the new organisation in the municipality of Uppsala. The purpose of this essay is to study the citizendialogue in the district of Rasbo. This will be done partly by an examination of how the participants themselves perceive citizendialogue. Their descriptions are put in relation to deliberative democracy and its critics amongst other. Partly by study how those involved have choosen to put it into practice. The opponents of the reorganization chose to start a non-profit association, Rasbo in co-operation, to carry on local mobilization and it will be compared with other similar groups. The municipality of Uppsala arranged a citizens forum in the district of Rasbo and the essay will examine how the participants experienced it. The study is based upon a total of 19 semistructured interviews with politicians and officials in the municipality of Uppsala and also working members of Rasbo in co-operation. The overall result of the analysis is that the politicians and the officials as well as the members of the association support the form of actions that endorse the representative system and look att citizendialogue as a tool to regenerate it and make it better. Rasbo in co-operation has almost everything in common with similar groups including a contradictory view on politics. The association has the important requirements for local mobilization, dedicated people, a positive collective identity and a constructive relation to the municipality. The participants of the citizens forum liked the way the forum was arranged and enjoyed the evening. But there was some problem between the unicipality and the association in connection with the preliminaries before the event. There is also some deficiency in the follow-up. Keyword: local democracy, citizendialogue, deliberative democracy, local mobilization, citizens forum, Uppsala, Rasbo, Rasbokil, Stavby, Tuna.
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Ecosystèmes microbiens des poissons tropicaux après abattage et incidence sur la salubrité des produits. / Microbial ecosystem of tropical fish, thunnus albacares and sciaenops ocellatus, post mortem and impact on the quality of the productsDauchy, Adèle 08 December 2016 (has links)
Le poisson est un produit très périssable dont l’altération résulte essentiellement de la croissance bactérienne. Comparé aux régions tempérées, peu d’études portent sur le microbiote d’altération des poissons tropicaux. En Martinique, le thon jaune (Thunnus albacares) et l’ombrine ocellée (Sciaenops ocellatus) représentent des poissons d’intérêt pour les filières pêche et aquaculture. Dans le but de mieux connaître le microbiote d’altération de ces poissons, des analyses culturales et aculturales (séquençage de nouvelle génération des amplicons d’ARNr 16S, Illumina MiSeq) ont été réalisées.Une grande diversité d’espèces bactériennes a été retrouvée dans le thon et l’ombrine fraîchement pêchés (104 et 887 OTUs, respectivement) et la plupart d’entre elles sont communément isolées des poissons (Chryseobacterium, Burkholderia, Flavobacterium, Psychrobacter, Arthrobacter, Staphylococcus). Certaines, comme Ralstonia sp. et Rhodanobacter terrae, en quantité importante dans le thon frais, sont plus atypiques. Au cours de l’entreposage du thon sous-glace, Pseudomonas et Brochothrix deviennent dominants. L’emballage sous atmosphère modifiée (MAP) ou sous vide (VP) entraine clairement la sélection de Brochothrix dans un cas et d’un mélange de Brochothrix, bactéries lactiques (Lactococcus piscium, Carnobacterium maltaromaticum) et d’entérobactéries (Hafnia paralvei) dans l’autre, et ne permet pas une augmentation significative de la durée de conservation. Pour les filets d’ombrine, peu de différences sont observées entre MAP et VP dont le microbiote se compose essentiellement de bactéries lactiques (Carnobacterium spp., Vagococcus spp., Lactococcus spp., Leuconostoc spp.). La durée de conservation est étendue de 15 jours par rapport au poisson entier sous air.L’inoculation de différentes espèces bactériennes dans de la chair pauci-microbienne de thon ou d’ombrine a montré que Hafnia paralvei et Serratia spp. sont les espèces les plus altérantes. Brochothrix thermosphacta et Carnobacterium spp. produisent aussi des odeurs indésirables mais de façon plus modérée. Chez Pseudomonas, les espèces ne sont pas toutes altérantes et présentent même parfois des capacités à empêcher le développement des mauvaises odeurs induites par d’autres bactéries (Pseudomonas psychrophila/fragi) et à dégrader l’histamine (Pseudomonas cedrina, Pseudomonas plecoglossicida/monteilii). En parallèle, des tests sensoriels et des dosages physico-chimiques ont également été réalisés pour comprendre les conséquences de la croissance bactérienne et identifier des indicateurs fiables pour l’évaluation du degré d’altération des produits. / Fish is a highly perishable product and spoilage is mainly due to the bacterial growth. Compared to temperate regions, few studies examined the spoilage microbiota of tropical fish. In Martinique, yellowfin tuna (Thunnus albacares) and red drum (Sciaenops ocellatus) are essential fish of fisheries and aquaculture sectors. For a better characterization of the microbial ecosystem, culture-dependent and culture-independent (next-generation sequencing of 16S rRNA amplicons, Illumina MiSeq) methods were carried out.A wide diversity of species was found in freshly caught tuna and red drum (104 and 887 OTUs, respectively) and most of them are commonly isolated from fish (Chryseobacterium, Burkholderia, Flavobacterium, Psychrobacter, Arthrobacter, Staphylococcus). Others, such as Ralstonia sp. and Rhodanobacter terrae, largely present in fresh tuna, are less familiar. During the ice-storage of tuna, Pseudomonas and Brochothrix became dominant. The modified atmosphere packaging (MAP) and vacuum packaging (VP) clearly leaded to the selection of Brochothrix in one case and to a mixture of Brochothrix, lactic acid bacteria (Lactococcus piscium, Carnobacterium maltaromaticum) and enterobacteria (Hafnia paralvei) in the other case, and not conduct to a significant increase of the shelf-life. For red drum fillets, few differences were observed between MAP and VP with a microbiota essentially composed by lactic acid bacteria (Carnobacterium spp., Vagococcus spp., Lactococcus spp., Leuconostoc spp.). The shelf-life was extended by 15 days compared to the whole fish ice-stored.The inoculation of different bacterial species into the pauci-microbial flesh of tuna or red drum showed that Hafnia paralvei and Serratia spp. were the most spoiling bacteria. Brochothrix thermosphacta and Carnobacterium spp. produced more moderate undesirable odors. Among the Pseudomonas genus, not all species induced spoiling effects and some of them are even able to prevent the development of unpleasant odors from other bacteria (Pseudomonas psychrophila/fragi) and to degrade histamine (Pseudomonas cedrina, Pseudomonas plecoglossicida/monteilii).At the same time, sensory tests and physico-chemical assays were performed to understand the consequences of the bacterial growth and to identify reliable indices for the evaluation of the spoilage degree of the products.
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Caractérisation des courants de fuite à l'échelle nanométrique dans les couches ultra-minces d'oxydes pour la microélectronique / Nanoscale characterization of leakage currents in ultra-thin oxide layers for microelectronicsHourani, Wael 09 November 2011 (has links)
La miniaturisation de la structure de transistor MOS a conduit à l'amincissement de l’oxyde de grille. Ainsi, la dégradation et le claquage sous contrainte électrique est devenu l'un des problèmes de fiabilité les plus importants des couches minces d'oxydes. L'utilisation de techniques de caractérisation permettant de mesurer les courants de fuite avec une résolution spatiale nanométrique a montré que le phénomène de claquage des oxydes est un phénomène très localisé. Le diamètre des «points chauds», des endroits où le courant de fuite est très élevé pour une tension appliquée continue, peut-être de quelques nanomètres uniquement. Ceci illustre pourquoi les méthodes de caractérisation avec une résolution spatiale à l’échelle nanométrique peuvent fournir des informations supplémentaires par rapport à la caractérisation classique macroscopique. Il y a deux instruments, dérivés de la microscopie à force atomique (AFM) qui peuvent être utilisés pour faire ce travail, soit le Tunneling Atomic Force Microscope (TUNA) ou le Conductive Atomic Force Microscope (C-AFM). Le mode TUNA qui est utilisé dans notre travail est capable de mesurer des courants très faibles variant entre 60 fA et 100 pA. Notre travail peut être divisé en deux thèmes principaux: - La caractérisation électrique des couches minces d'oxydes high-k (LaAlO3 et Gd2O3) à l'échelle nanométrique en utilisant le Dimension Veeco 3100 où nous avons montré que la différence de leurs techniques d'élaboration influe largement sur le comportement électrique de ces oxydes. - Les caractérisations électriques et physiques à l’échelle nanométrique des couches minces d’oxydes thermiques SiO2 sous différentes atmosphères, c.à.d. dans l'air et sous vide (≈ 10-6 mbar) en utilisant le microscope Veeco E-Scope. L'influence de l’atmosphère a été bien étudiée, où nous avons montré que les phénomènes de claquage des couches minces d'oxydes peuvent être fortement réduits sous vide surtout en l'absence du ménisque d'eau sur la surface de l'oxyde pendant les expériences. En utilisant les plusieurs modes de l'AFM, il a été démontré que l'existence de bosses anormales (hillocks) sur la surface de l'oxyde après l'application d'une tension électrique est une combinaison de deux phénomènes: la modification morphologique réelle de la surface de l'oxyde et la force électrostatique entre les charges piégées dans le volume de l'oxyde et la pointe de l'AFM. Selon les images du courant obtenues par AFM en mode TUNA, deux phénomènes physiques pour la création de ces hillocks ont été proposés: le premier est l'effet électro-thermique et la seconde est l'oxydation du substrat Si à l’interface Si/oxyde. / Miniaturization of the MOS transistor structure has led to the high thinning of the gate oxide. Hence, degradation and breakdown under electrical stress became one of the important reliability concerns of thin oxide films. The use of characterization techniques allowing to measure leakage currents with a nanometric spatial resolution has shown that breakdown phenomenon of oxides is a highly localized phenomenon. So called “hot spots”, places where the leakage current is very high for a given applied continuous voltage, can be several nanometers wide only. This illustrates why nanometric characterization methods with a nanometer range spatial resolution provide additional information compared to the classical macroscopic characterization. There are two instruments that can be used to do this job, either the Tunneling Atomic Force Microscope (TUNA) or the Conductive Atomic Force Microscope (C-AFM). TUNA which is used in our work is capable to measure very low currents ranging between 60 fA and 100 pA. Our work can be divided into two principle topics: - Electrical characterization of thin high-k oxides (LaAlO3 and Gd2O3) at the nano-scale using the Veeco Dimension 3100 where we have shown that the difference in their elaboration techniques largely influence the electrical behavior of these oxides. - Nano-scale electrical and physical characterization of thin SiO2 thermal oxides in different surrounding ambient, that is in air and under vacuum (≈ 10-6 mbar) using the Veeco E-scope microscope. The influence of the experiment surrounding ambient has been well studied where we have shown that the breakdown phenomena of thin oxide films can be highly reduced under vacuum especially in the absence of the water meniscus on the oxide’s surface under study. Using different AFM modes, it was demonstrated that the existence of the well-known hillock (protrusions) on the oxide’s surface after the application of an electrical stress is a combination of two phenomena: the real morphological modification of the oxide’s surface and the electrostatic force between the trapped charges in the oxide’s volume and the AFM tip. Depending on the current images obtained by TUNA AFM mode, two physical phenomena for the creation of these hillocks have been proposed: the first is the electro-thermal effect and the second is the oxidation of the Si substrate at the Si/oxide interface.
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Digestion anaérobie d'effluents d'une conserverie de thon tunisienne : aspects biotechnologiques et microbiologiques. / Anaerobic digestion of Tunisian manure from a tuna cannery : biotechnology and microbiological aspectsHamdi, Olfa 02 April 2015 (has links)
Deux réacteurs, R1 et R2, ont été alimentés quotidiennement avec les effluents à traiter à des TRH de 13 jours et de 20 jours, respectivement. Les résultats obtenus ont montré un taux d'abattement de la dégradation de la matière organique de 53% pour R2, contre 35% pour R1. Afin de mieux comprendre le fonctionnement biologique de ces réacteurs, nous avons exploré les communautés microbiennes d'importance écologique impliquées dans la dégradation de la matière organique contenue dans ces effluents. Cela a été réalisé dans un premier temps par des approches moléculaires en utilisant la technique de DGGE et le pyroséquençage 454. Nous avons alors montré que les représentants du domaine des Bacteria étaient les plus représentés dans les deux réacteurs par rapport aux Archaea avec une plus grande diversité au niveau du réacteur R2. Les séquences de Bacteria obtenues sont affiliées principalement aux phylums des Firmicutes, des Bacteroïdetes, et des Synergistetes, impliquées dans l'hydrolyse et la fermentation de la matière organique des effluents. Une mention particulière est à accorder aux membres du phylum des Synergistetes qui ont été également détectés par pyroséquençage 454. Dans les deux réacteurs, ce phylum majoritaire était représenté par deux familles, celle des "Dethiosulfovibrionaceae" et celle des "Aminiphilaceae" dont on sait qu'elles interviennant dans la dégradation des acides aminés. Enfin, l'approche culturale nous a permis d'isoler dans nos réacteurs plusieurs souches bactériennes anaérobies mésophiles hétérotrophes. Parmi celles-ci, nous avons pu décrire deux nouvelles espèces Desulfocurvus thunnarius et A thunnarium. / For this purpose, two ASBR reactors R1 and R2 were tested. They were fed daily with the industrial effluents at HRT of 13 days and 20 days, respectively. The results obtained during the anaerobic treatment showed a degradation rate of the organic matter of 53% for R2 against 35% for R1. In order to better understand this process, we explored the microbial communities of ecological importance involved in the degradation of organic matter in the effluent to be treated. This was accomplished by initiating molecular approaches. Using the DGGE technique and 454 pyrosequencing, we showed that representatives of the domain Bacteria were the most dominant in both reactors as compared to Archaea with a greater diversity observed in R2 reactor. Bacteria sequences were affiliated to the phyla Firmicutes, Bacteroidetes and Synergistetes, known to be involved in the hydrolysis and fermentation of organic matter. A particular mention is given to members of the phylum Synergistetes which were also detected by pyrosequencing 454. In both reactors, this phylum was represented by two families, the "Dethiosulfovibrionaceae" and that of "Aminiphilaceae" which are recognized as significant amino acids degraders. Finally, the cultivation approach allowed us to isolate several mesophilic heterotrophic anaerobic bacteria. Among them, a new sulfate-reducing species belonging to the family Desulfovibrionaceae, Desulfocurvus thunnarius, and A thunnarium.
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Physicochemical and rheological properties of interacted protein hydrolysates derived from tuna processing by-products with sodium alginateGao, Jingrong, He, Shan, Nag, Anindya, Zeng, Xin-An 04 April 2024 (has links)
The physicochemical properties of tuna protein hydrolysates were enhanced by interaction with sodium alginate. The increase in emulsifying capacity and stability was from 50 to 150 m² g⁻¹ and from 36 to 49 min, respectively. The increase in foaming capacity and stability was from 100% to 140% and from 65% to 70%, respectively. The reason for the increased physicochemical properties was the reduced zeta potential level of tuna protein hydrolysates after interaction with sodium alginate. The change in internal structure of tuna protein hydrolysates after interaction with sodium alginate was determined by SEM and FTIR. The SEM results showed that a net cross-linking structure was formed from a sheet structure after the tuna protein hydrolysates interacted with sodium alginate. FTIR demonstrated that parts of the β-sheet of tuna protein hydrolysates were changed into an irregular coiled structure or α-helix after interaction with sodium alginate. In order to understand the interacted complex better, the rheological properties of interacted tuna protein hydrolysates with sodium alginate were further determined. In this study, the one-step was developed, easy-to-operate and cost-effective process that can further add value to tuna protein hydrolysates derived from tuna processing by-products.
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