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1
Sole, Catherine Lynne. "Phylogeography of Scarabaeus (Pachysoma) macleay (Scarabaidae : scarabaeinae)." Pretoria : [s.n.], 2005. http://upetd.up.ac.za/thesis/available/etd-01302006-123900.
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Franzini, Philippa Zena Nel. "The gut microbiomes of desert Pachysoma spp. MacLeay (Coleoptera: Scarabaeidae)." Thesis, University of Pretoria, 2017. http://hdl.handle.net/2263/63218.
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Microbial communities inhabit many environmental niches including the nutrient-rich gut
systems of animals, where they are involved in a number of important processes. Insect gut
microbiota may assist the host with several functions including synthesis of nutritional
components lacking from the host diet and digestion of lignocellulosic materials. It is generally
believed that the diet of the host plays an important role in the structure of the gut microbiome.
Numerous studies have focused on insects feeding on lignocellulosic diets such as termites,
as well as medically and agriculturally important insect species. Few studies have researched
the gut microbiota of adult dung beetles. Most scarab beetle species feed on the liquid
component of wet dung, whereas Pachysoma spp. may feed on lignocellulosic materials within
their diet of dry dung, plant detritus or both. This feeding behaviour makes Pachysoma an
ideal candidate for studying the role that diet has on gut microbiome assembly.
Plant detritus feeding P. endroedyi and the dry dung feeding P. striatum were collected
from Namaqualand, South Africa. The mid- and hindgut of each individual were dissected and
mDNA extracted using a phenol-chloroform method. Amplicon sequencing of the bacterial 16S
rRNA gene and the fungal ITS region was used to determine inter- and intra-specific
differences in microbial community structures. Shotgun sequencing of the entire gut
metagenome was carried out on mDNA extracted from whole gut samples. Shotgun
sequencing was used for both taxonomic and functional annotation of the Pachysoma gut
microbiomes.
Both amplicon and shotgun sequencing detected substantial differences in bacterial and
fungal diversity between the two Pachysoma species. Amplicon sequencing showed the
number of bacterial phyla ranged from 6-11 and 4-7 (total 14 phyla) for P. endroedyi and P.
striatum, respectively. Furthermore, a minimal core microbiome was detected with only 2.57%
of the bacterial OTUs shared between the two Pachysoma species studied. Large intraspecific
variations were also noted within both Pachysoma species. Fungal communities could
not be detected in the gut of P. endroedyi, while only two fungal phyla were detected P. striatum gut samples. Metagenome shotgun sequencing detected a greater bacterial diversity
(total of 39 phyla) than the 16S rRNA gene amplicon study, although large differences were
noted between the two species. Furthermore, shotgun sequencing demonstrated that fungal
communities were present in the guts of both Pachysoma species. Archaea, viruses and other
eukaryotic microorganisms were also present in the gut metagenomes of both Pachysoma
species.
The functional capacity of the Pachysoma spp. gut microbiomes was analysed using
shotgun sequencing. Both species had the genetic capacity to degrade cellulose and
hemicellulose but not lignin, supporting the suggestion that P. striatum feeds on plant material
in the dry dung. Furthermore, the functional capacity of the microbiomes of both Pachysoma
species were comparable, suggesting the ability for both species to feed on either dry dung or
plant detritus. The similarity of the functional profiles of the two Pachysoma species suggests
the existence of a functional rather than phylogenetic core microbiome
This primary study has successfully characterised the phylogenetic and functional
profiles of the gut microbiomes of two Pachysoma species feeding on different substrates.
However, it is still unclear if diet is the primary driver in gut microbiome assembly.Thesis (PhD)--University of Pretoria, 2017.
National Research Foundation (NRF)
Genetics
PhD
Unrestricted
3
Harrison, James due Guesclin. "Systematics of the endemic south-west African dung beetle genus Pachysoma Macleay (Scarabaedae : Scarabaeinae)." Pretoria : [s.n.], 2006. http://upetd.up.ac.za/thesis/available/etd-12062006-153927.
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Vezzani, Renata de Macedo [UNESP]. "Taxonomia e biogeografia da família Goneplacidae Macleay, 1838 (Crustacea : Decapoda : Brachyura) no litoral brasileiro." Universidade Estadual Paulista (UNESP), 2007. http://hdl.handle.net/11449/99569.
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vezzani_rm_me_rcla.pdf: 2177233 bytes, checksum: e29a88d5a71c145411a89ed669d43dfc (MD5)A família Goneplacidae com representantes em todos os oceanos tropicais e temperado-quentes inclui 7 gêneros e 13 espécies na costa brasileira. Embora, muito tenha sido escrito sobre os aspectos ecológicos e fisiológicos, a taxonomia do grupo ainda possui problemas a serem resolvidos, porque a bibliografia sobre os Goneplacidae brasileiros está restrita a levantamentos faunísticos, tratamentos sistemáticos de poucos gêneros importantes e indicações de novas ocorrências na costa brasileira. Sobre biogeografia, não há quase nada referente às espécies brasileiras. De fato, os Goneplacidae nunca receberam, no Brasil, nenhuma revisão taxonômica do ponto de vista global. Considerando estes fatos, a revisão deste grupo foi feita usando as coleções carcinológicas do Museu de Zoologia da Universidade de São Paulo e de outros museus brasileiros. Dois padrões longitudinais de distribuição e três padrões latitudinais foram verificados nos Goneplacidae brasieliros.
The family Goneplacidae with representatives in all the tropical and warm temperate oceans includes 7 genera and 13 species on the Brazilian coast. Although much has been written about ecological and physiological aspects, the taxonomy of the group left problems to be solved, because present bibliography on Brazilian Goneplacidae is restricted to a few faunistic surveys, in a few areas, systematic treatments of a few important genera and reports of a new occurrences on the Brazilian coast. As for biogeography there is almost nothing about Brazilian species. In fact, the Goneplacidae had never received, in Brazil, any taxonomic revision, at least not from a global view point. Considering these facts, a revision of this group was made using the carcinological collections of the Museu de Zoologia da Universidade de São Paulo and other Brazilian museums. Two patterns of longitudinal distribution and three patterns of latitudinal distribution were verified among the Brazilian Goneplacidae.
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Vezzani, Renata de Macedo. "Taxonomia e biogeografia da família Goneplacidae Macleay, 1838 (Crustacea : Decapoda : Brachyura) no litoral brasileiro /." Rio Claro : [s.n.], 2007. http://hdl.handle.net/11449/99569.
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Orientador: Gustavo A.S. de MeloBanca: Nilton José Hebling
Banca: Oswaldo Campos Junior
Resumo: A família Goneplacidae com representantes em todos os oceanos tropicais e temperado-quentes inclui 7 gêneros e 13 espécies na costa brasileira. Embora, muito tenha sido escrito sobre os aspectos ecológicos e fisiológicos, a taxonomia do grupo ainda possui problemas a serem resolvidos, porque a bibliografia sobre os Goneplacidae brasileiros está restrita a levantamentos faunísticos, tratamentos sistemáticos de poucos gêneros importantes e indicações de novas ocorrências na costa brasileira. Sobre biogeografia, não há quase nada referente às espécies brasileiras. De fato, os Goneplacidae nunca receberam, no Brasil, nenhuma revisão taxonômica do ponto de vista global. Considerando estes fatos, a revisão deste grupo foi feita usando as coleções carcinológicas do Museu de Zoologia da Universidade de São Paulo e de outros museus brasileiros. Dois padrões longitudinais de distribuição e três padrões latitudinais foram verificados nos Goneplacidae brasieliros.
Abstract:The family Goneplacidae with representatives in all the tropical and warm temperate oceans includes 7 genera and 13 species on the Brazilian coast. Although much has been written about ecological and physiological aspects, the taxonomy of the group left problems to be solved, because present bibliography on Brazilian Goneplacidae is restricted to a few faunistic surveys, in a few areas, systematic treatments of a few important genera and reports of a new occurrences on the Brazilian coast. As for biogeography there is almost nothing about Brazilian species. In fact, the Goneplacidae had never received, in Brazil, any taxonomic revision, at least not from a global view point. Considering these facts, a revision of this group was made using the carcinological collections of the Museu de Zoologia da Universidade de São Paulo and other Brazilian museums. Two patterns of longitudinal distribution and three patterns of latitudinal distribution were verified among the Brazilian Goneplacidae.
Mestre
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ALBUQUERQUE, Larissa Simões Corrêa de. "Influência de fatores abióticos sobre o período de atividade de dynastinae macleay (melolonthidae) noturnos em um fragmento de Floresta Atlântica de Pernambuco." Universidade Federal de Pernambuco, 2013. https://repositorio.ufpe.br/handle/123456789/11730.
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CNPq, Campo de Instrução Marechal Newton Cavalcante, Exército Brasileiro
O objetivo deste trabalho foi verificar a influência dos fatores abióticos sobre a atividade noturna de voo das espécies de Dynastinae (Coleoptera, Melolonthidae) em um fragmento de floresta Atlântica de Pernambuco. Foram realizadas coletas noturnas, em um intervalo de 30 dias, durante dezembro de 2010 a novembro de 2011 (exceto abril de 2012), utilizando armadilha pano iluminado, das 17 às 5h. Foram realizadas as análises de Correlação de Spearman para verificar a influência dos fatores abióticos sobre a atividade de voo desses besouros; o escalonamento multidimensional não-métrico (NMDS) foi executado, utilizando a distância de Bray-Curtis, para observar a influência da estação sobre abundância e composição de espécies; e o teste de Rayleigh (estatística circular) foi utilizado para determinar o pico do horário de voo das espécies desse grupo. Foram coletados 456 indivíduos pertencentes a três tribos, sete gêneros e 12 espécies. A tribo de maior riqueza foi Cyclocephalini e a espécie mais abundante foi Cyclocephala distincta Burmeister, 1847. A pluviometria, umidade do ar e umidade do solo influenciaram a atividade de voo de seis espécies e as estações do ano não exerceram influência na abundância das espécies e na composição destas. Das espécies mais abundantes, três apresentaram pico de atividade entre às 18-20h, e outras três entre as 20-22h. Conclui-se que, no fragmento amostrado, houve influência dos fatores abióticos sobre a atividade de voo de algumas espécies de Dynastinae. Ainda, sazonalidade em relação a sua abundância e seis táxons apresentam horário de atividade de voo específicos.
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Judge, David, and n/a. "The Ecology of the polytopic freshwater turtle species, Emydura macquarii macquarii." University of Canberra. Resource, Environmental and Heritage Sciences, 2001. http://erl.canberra.edu.au./public/adt-AUC20050418.151350.
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An ecological study of Emydura macquarii macquarii in the south-east region
of Australia was conducted between October 1995 and March 1998. E. m. macquarii is
an abundant and widespread species of short-necked turtle that is highly variable in
morphology and related life history attributes. No study in Australia had previously
looked at geographic variation in biological traits in freshwater turtles, hence the level
of variation in E. m. macquarii had been poorly documented. The principal aims of this
study were to investigate the plasticity of life history traits across populations of E. m.
macquarii and to speculate on possible causes. A more intensive study was also
conducted on a rare and suspected declining population of E. m. macquarii in the
Nepean River to determine whether relevant management and conservation measures;
were required.
The study involved comparing various life history attributes between five
populations of E. m. macquarii (Brisbane River, Macleay River, Hunter River, Nepean
River and Murray River). The populations were specifically chosen to account for the
range of variation in body size within this subspecies. Body size (maximum size, size at
maturity, growth rates), population structures (sex ratios, age and size structures),
reproductive traits (clutch mass, clutch size, egg size, egg content, etc.) and other
attributes were collected for each population. Patterns of life history traits, both within
and among populations, were explored so that causes of variation could be sought.
Geographic variation in Body Size and other Related Life History Traits
Body size in E. m. macquarii differed markedly between populations. Females
ranged in maximum sizes (carapace length) of 180 mm in the Macleay River to over
300 mm in the Murray River. E. m. macquarii was sexually dimorphic across all
populations with females larger than males in all cases. Maximum body size was
positively related to the size at which a turtle matures. The size at maturity in turn was
positively related to juvenile growth rates. Age was a more important factor for males
in terms of timing of maturity whereas in females it was body size. Morphological
variation was not only great between populations, but also within populations.
Maximum body size was unrelated to latitude; hence it was inferred that habitat
productivity had the most important influence on geographic variation in body size.
Population structures also differed between populations. Sex ratios did not differ in the
Brisbane, Macleay and Murray Rivers. However, a male bias was present in the Nepean
River population and a female bias in the Hunter River. Juveniles were scarce in the
Brisbane and Macleay Rivers but numerous in the Nepean and Hunter Rivers.
Geographic Variation in Reproduction
There was large variation in reproductive traits across populations of E. m.
macquarii. Nesting season began as early as mid-September in the Brisbane River and
as late as December in the Hunter River, and continued until early January. Populations
in the Hunter and Murray Rivers are likely to produce only one clutch per season while
populations from the Macleay and Nepean Rivers can produce two, and on some
occasions, three clutches annually. The majority of females would appear to reproduce
every year.
Clutch mass, clutch size, and egg size varied greatly both within and among
populations. A large proportion of variation in reproductive traits was due to the effects
of body size. E. m. macquarii from large-bodied populations such as in the Brisbane
and Murray Rivers produced bigger eggs than small-bodied populations. Within a
population, clutch mass, clutch size, and egg size were all correlated with body size,
except the Nepean River. The variability of egg size was smaller in large-bodied
populations where egg size was more constant.
Not all variation in reproductive traits was due to body size. Some of this
variation was due to annual differences within a population. Reproductive traits within
a population are relatively plastic, most likely a result of changing environmental
conditions. Another source is the trade-off between egg size and clutch size. A negative
relationship was found between egg size and clutch size (except the Brisbane River).
Reproductive variation was also influenced by latitudinal effects. Turtles at lower
latitudes produces more clutches, relatively smaller clutch sizes, clutch mass and larger
eggs than populations at higher latitudes. Annual reproductive output is greater in
tropical populations because they can produce more clutches per year in an extended
breeding season.
Eggs that were incubated at warmer temperatures hatched faster and produced
smaller hatchlings. Incubation temperatures above 30�C increased egg mortality and
hatchling deformities, suggesting this is above the optimum developmental temperature
for E. m. macquarii. Hatchling size was positively related to egg size, hence hatchling
sizes was on average larger in the Murray and Brisbane rivers. However, population
differences remained in hatchling size after adjustments were made for egg size. For
example, hatchlings from the Hunter River were smaller than those from the Macleay
River despite the egg size being the same. These differences were most likely due to the
shorter incubation periods of hatchlings from the Hunter River.
Nepean River
The Nepean River population of E. m. macquarii is at the southern coastal limit
of its range. This is a locally rare population, which is believed to be declining. This
study aimed at determining the distribution, abundance, and population dynamics to
assess whether any conservation management actions were required. E. m. macquarii in
the Nepean River was mainly concentrated between Penrith and Nortons Basin,
although even here it was found at a very low density (10.6 - 12.1 per hectare). The
largest male caught was 227 mm while the largest female was 260.4 mm. Males
generally mature between 140 - 150 mm in carapace length and at four or five years of
age. Females mature at 185 -195 mm and at six to seven years of age.
Compared with other populations of E. macquarii, Nepean River turtles grow
rapidly, mature quickly, are dominated by juveniles, have a male bias and have a high
reproductive output. Far from being a population on the decline, the life history traits
suggest a population that is young and expanding. There are considered to be two
possible scenarios as to why the Nepean River population is at such a low density when it appears to be thriving. The first scenario is that the distribution of the population on
the edge of its range may mean that a small and fluctuating population size may be a
natural feature due to sub-optimal environmental conditions. A second scenario is that
the population in the Nepean River has only recently become established from dumped
pet turtles.
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OLIVEIRA, Danielly Brito de. "Variação mensal da densidade das larvas de Anomura macleay, 1838, Axiidea saint laurent, 1979 e Gebiidae saint laurent, 1979 (Crustacea, Decapoda) em um estuário amazônico (Pará, Brasil), com descrição dos primeiros estágios larvais de Upogebia vasquezi ngoc-ho, 1989 obtidos em laboratório." Universidade Federal do Pará, 2010. http://repositorio.ufpa.br/jspui/handle/2011/3496.
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A dissertação foi elaborada no formato de artigos, separados em capítulos, conforme formatação do Programa de Pós-Graduação em Ecologia Aquática e Pesca da Universidade Federal do Pará. O capítulo geral contém uma breve introdução sobre a biologia geral de anomuros (Infraordem Anomura) e talassinóideos (Infraordens Axiidea e Gebiidea), seguido pelos objetivos e metodologia geral utilizada para a obtenção dos resultados que culminaram com a elaboração dos três capítulos restantes da dissertação, que serão submetidos à publicação. O capítulo 1 foi específico para a investigação da variação espaço-temporal das espécies de anomuros que utilizam o estuário de Marapanim (PA) durante a fase larval, e sua relação com os fatores abióticos (temperatura, salinidade e pH). O capítulo 2 contém os resultados obtidos quanto à ocupação do estuário pelas larvas e adultos das espécies de talassinóideos obtidas ao longo dos meses do ano. Este foi o único grupo em que houve a possibilidade de analisar, de forma integrada, as amostras de larvas, juvenis e adultos presentes no estuário. Em razão da dificuldade encontrada na identificação das amostras de larvas de Decapoda (Anomura, Axiidea e Gebiidea) coletadas no estuário de Marapanim (PA) ao longo do ano, optou-se por efetuar o desenvolvimento larval de Upogebia vasquezi, obtido em laboratório, culminando com a inclusão do capítulo 3, que contém a descrição dos dois primeiros estágios larvais desta espécie. Por fim foram apresentadas as conclusões gerais e as perspectivas de continuidade nos estudos com estes táxons nos estuários paraenses.
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Kerr, Sheila Margaret. "An assessment of a Soviet agent : Donald MacLean, 1940-1951." Thesis, London School of Economics and Political Science (University of London), 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.339001.
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Schneider, Ulrich Johannes. "Maclean, Ian: Montaigne als Philosoph. Fink, München 1998, 120 S. (Rezension)." Universitätsbibliothek Leipzig, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-151923.
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Montaigne als Philosoph: Das ist bei Maclean der im 16. Jahrhundert studierte Jurist Montaigne, der methodisch und sachlich die Gepflogenheiten wissenschaftlichen Disputierens kennt und beherrscht. Dass alle Kenntnisse und Wissenschaften In Montaignes Essais wie zusammengestürzt präsent sind, lässt Maclean schließlich von den "Trümmern eines philosophischen Gebäudes" sprechen.
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Schneider, Ulrich Johannes. "Maclean, Ian: Montaigne als Philosoph. Fink, München 1998, 120 S. (Rezension)." Lendemains, 95/96 (1999), S. 188-191 ISBN 978-3-86057-965-7, 1999. https://ul.qucosa.de/id/qucosa%3A12904.
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Montaigne als Philosoph: Das ist bei Maclean der im 16. Jahrhundert studierte Jurist Montaigne, der methodisch und sachlich die Gepflogenheiten wissenschaftlichen Disputierens kennt und beherrscht. Dass alle Kenntnisse und Wissenschaften In Montaignes Essais wie zusammengestürzt präsent sind, lässt Maclean schließlich von den "Trümmern eines philosophischen Gebäudes" sprechen.
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Griffin, Donna-Lee. "Frontier heartland : analysing the impact of forestry and tourism on 'white' identity in Maclear." Thesis, Rhodes University, 2006. http://hdl.handle.net/10962/d1008066.
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The North Eastern Cape in South Africa is part of a larger province that is in desperate need of job creation and economic development. In light of these needs, efforts have been made by members of the community and outside investors to generate new forms of income in the area. These economic developments emerged in the form of small-scale tourism initiatives and commercial forestry. The impact of these developments on the small community of Maclear differs in nature and is bringing about social change and influencing identity. In this thesis, I explore the effects of each of these developments on the local farming community, particularly the established white English-speaking farmers. For various important reasons, such as the changes to land use patterns occurring around them in terms of forestry and tourism initiatives, I chose to examine the situation of this minority. In general discussions and portrayals of white farmers, it is hypothesized that whites living in small farming communities are resistant to change, politically stagnant and socially conservative. In this thesis I test this hypothesis and investigate what South Africans might see as the core, or whether there is a core of, white settler identity. TIle idea of 'frontiers' being heartlands was emphasized in Maclear as residents spoke about the pioneering efforts of their forefathers and discussed these efforts as the essence of their identity. Forestry is a contemporary ' frontier' encroaching on these white Settlers. A dynamic concept of landscape is central to these identity construction efforts. In this thesis I explore, through different articulations of landscape, how residents, recent arrivals and investors attempt to embed their identity and resources in the community. I ask whether it is possible for members of the white community to produce an alternate and politically viable interpretation of landscape in post-apartheid South Africa. Can land and landscape offer them a sense of belonging and identity? What is their experience in view of the impositions of major investors who see land purely as an economic unit? The research does not explicitly investigate how 'new' black farmers and farming groups perceive and experience land and landscape. What is noted is the imagined passivity of black labourers on white-owned land. This thesis touches on issues inlportant to democratic change and progress in South Africa. How will the new government deal with the thorny issue of land redistribution in the face of competing claims for land and identity? How will the various sections of the white community (in this case the farming community) negotiate their identity in the new South Africa? Also, what do ' frontier' towns like Maclear reveal about the nature of white identity in post-apartheid South Africa? This thesis relies on gender and constructionist theories of landscape as developed by Appadurai (1996) to explain the dynamic nature of landscape in Maclear. It also explores and appraises the idea of ' frontier'. In the analysis of identity, I take into account that white settlers 'success' relies in part on the settlers ability to adapt to the ' frontier' and their ability to construct a new identity in their newfound 'homeland' (simliar to Paul Gilroy's (1993) "double consciousness). Keywords: South Africa, Maclear, Farming, White Identity, Landscape and Tourism.
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Dunbar, Robert Douglas. "The secular poetry of John MacLean "Bàrd Thighearna Chola", "Am Bàrd MacGilleain"." Thesis, University of Edinburgh, 2007. http://hdl.handle.net/1842/22165.
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John MacLean (1787-1848) was a native of Caolas, Tiree, who emigrated to Nova Scotia, Canada in 1819. In Scotland, he is known to this day by Gaelic speakers as “Bàrd Thighearna Chola ”, “The Poet to the Laird of Coll”, and he is one of the last Gaelic poets to have served as a poet for a Highland chieftain. In Nova Scotia, he is known as simply “Am Bàrd MacGilleain”, “The Bard MacLean”, and is regarded as perhaps the greatest of the many poets who emigrated from the Scottish Highlands and Islands in the main period of Highland Emigration (roughly, 1735-1850). In addition to being an important Gaelic poet, he was also a relatively early collector of Gaelic song and poetry. In spite of his importance as a poet, John MacLean’s poetry has never been subjected to sustained critical analysis, and this thesis will fill this gap. Furthermore, although the poet’s grandson, Rev. Alexander MacLean Sinclair, provided a brief portrait of the poet in several of his publications, we still lack a comprehensive biographic study of the poet. Finally, although the large majority of John MacLean’s poems have been published, particularly by Alexander MacLean Sinclair, the MacLean Sinclair published versions of the poetry, and those that derive therefrom, differ considerably – indeed radically – from the versions which appear in the poet’s manuscripts or in the collection of some of his poetry which the poet himself published in 1818.
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Fonda, Nick. "The fantastic worlds of Alistair Macleod and Michel Tremblay." Mémoire, Université de Sherbrooke, 1992. http://hdl.handle.net/11143/10913.
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Est-il possible de comparer des œuvres si différentes que celles d'Alistair MacLeod et de Michel Tremblay? Le mémoire vise à démontrer non seulement la possibilité, mais aussi la pertinence d'une telle comparaison. MacLeod, l'écrivain du Cap Breton, a publié quinze contes. Tremblay, son homologue contemporain québécois, a publié une vingtaine de pièces de théâtre, de contes, quelques scénarios de film, huit romans et un livret d'opéra. Nous allons démontrer qu'en dépit de cette disproportion, deux principaux parallèles peuvent être établis entre leurs œuvres. D'une part les deux auteurs ont créé des mondes littéraires très réalistes dans lesquels se manifeste par ailleurs le fantastique. D'autre part, tous deux expriment, par le biais du fantastique, leur préoccupation pour la survie de leur peuple respectif. Le premier chapitre est consacré à l'examen critique du fantastique comme genre littéraire. Les théories contemporaines de l'américain Rabkin et du français Todorov retiendront particulièrement notre attention. Selon Rabkin, contrairement au non pertinent et à l'imprévu (les deux genres voisins entre lesquels il le situe), le fantastique naît de l'étonnement éprouvé lorsque les règles implicites présidant à la lecture basculent ou, pour reprendre son expression, sont retournées de 180 degrés. Quant à Todorov, il situe le fantastique entre l'étrange (qui s'explique par les lois naturelles) et le merveilleux (qui suppose l'existence d'un mode surnaturel). Le fantastique constitue ainsi un genre éphémère qui n'existe qu'à la condition que le lecteur soit dans l'incertitude, ayant à choisir entre une explication réelle (l'étrange) ou surnaturelle (le merveilleux). Nous montrerons que malgré leurs différences, ces définitions sont convergentes en égard notamment à l'importance du temps et aux frontières définitions du fantastique. Au chapitre suivant, il sera question des contes d'Alistair MacLeod. Ceux-ci ont été très bien reçus par la critique canadienne et étrangère ainsi que par le public. Ces contes traitent presqu'exclusivement des trois "vies" de I'lle du Cap Breton: labourer la terre, pêcher dans la mer, exploiter le charbon. Les histoires de MacLeod sont peuplées par des gens pauvres mais fiers, forts et courageux. En contact avec la terre, ils sont aussi en contact avec la mort foudroyante, fulgurante engendrée par des métiers dangereux. La première collection de MacLeod, The Lost Sait Gift of Blood (1976), est dominée par le thème du départ. Dans presque chaque histoire, MacLeod présente des hommes qui doivent quitter leur terre ancestrale. Le minerai de charbon est épuisé, la petite ferme familiale n'est plus rentable, le poisson est désormais péché par des navires-usines qui viennent de loin. Dans la deuxième collection. As Birds Bring Forth the Sun (1986), le thème du départ cède la place à celui de la mort. Souvent les histoires sont narrées par des hommes qui ont quitté le Cap Breton, des exilés économiques qui se rappellent avec nostalgie leur pays natal. L'analyse mettra en lumière le fait que, surtout dans sa toute dernière histoire, "Island", la mort de l'individu symbolise celle du Cap Breton.
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Lima, Tiago Ronimar Ferreira. "Efeito de extratos de plantas no controle do estresse oxidativo em ovinos confinados alimentados com dieta com elevada proporção de concentrado." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/74/74131/tde-03112016-091721/.
Full textAbstract:
O uso de dietas com elevado teor de concentrado para intensificar a produção de carne de ovinos pode influenciar a homeostase oxidativa do animal, com efeito no seu desempenho e na qualidade da carne. Para buscar meios alternativos, foram testados antioxidantes convencionais em comparação com extratos de plantas no controle do estresse oxidativo em cordeiros alimentados com dieta exclusiva de concentrado. Foram utilizados 48 cordeiros machos Dorper x Santa Inês com peso inicial de 20 ± 1,49 kg desmamados aos 60 dias e alojados em baias individuais e alimentados durante 60 dias com dieta exclusiva de concentrado, composta por 80% milho grão inteiro e 20% pelete proteico, com os tratamentos diferindo apenas na adição dos antioxidantes. Os tratamentos foram controle, sem adição de antioxidante, extrato de plantas com adição de 4 mg/kg de Macleya cordata e Magnolia oficcinalis, tratamento vitamina E e selênio nas quantidades 100UI/kg e 0,1 mg/kg, respectivamente e tratamento extrato de plantas + vitamina E e selênio, nas mesmas quantidades anteriores. A alimentação e a sobra foram pesadas diariamente para determinação de matéria seca e eficiência alimentar. Os animais foram pesados no início do experimento e a cada 14 dias para acompanhamento do desempenho. Foram perdidas duas parcelas experimentais. Durante o período experimental foram realizadas três colheitas de sangue para avaliação de parâmetros oxidativos e proteicos. Após o abate, foram retiradas amostras para análise em painel expositor refrigerado do Longissimus dorsi durante oito dias para influência da estabilidade oxidativa na cor. Houve influência no peso final, ganho diário, peso de carcaça e teor de Se no músculo L.dorsi para tratamentos com adição de vitamina E e Se. Não houve efeito de tratamento para proteínas sanguíneas, indicando que os animais estavam saudáveis durante o experimento. O uso de extrato de plantas teve efeito similar ao dos antioxidantes convencionais e pode ser usada no controle do estresse oxidativo.The use of high concentrate diets to intensify sheep meat production can influence the oxidative homeostasis of the animal, influencing performance and meat quality. In order to find alternative antioxidants this experiment was carried out to test conventional antioxidants in comparison with plant extracts in the control of oxidative stress in lambs fed exclusively a concentrate diet. Forty-eight male lambs Dorper x Santa Inês with initial weight of 20 ± 1.49 kg weaned at 60 days and housed in individual pens were used. The animals were fed a concentrate diet consisting of 80% whole corn grain and 20% protein pellet, and the treatments differed only in the addition of the antioxidants during 60 days. The treatments were control, no added antioxidant, treatment with plant extract with inclusion of 4 mg / kg plant extract of Macleya cordata and Magnolia oficcinalis, treatment with vitamin E and selenium in amounts of 100 IU / kg and 0.1 mg / kg, respectively, and treatment plant extract + vitamin E and selenium, in the same previous amounts cited. The feed and orts were weighed daily to determine the dry matter intake and feed efficiency. The animals were weighed at the beginning of the experiment and every 14 days to and two experimental units were lost. During the trial three blood samples were taken for evaluation of oxidative and protein parameters. After slaughter, test samples were taken in refrigerated display panel Longissimus dorsi for eight days to study the influence of the oxidative stability in color. There was influence in the final weight, daily gain, carcass weight and Se in the L.dorsi muscle of the treatment with the addition of vitamin E and Se. There was no effect of the plants extract treatment in the blood proteins, indicating healthy animals. The use of plant extracts have antioxidant had effect similar to conventional antioxidants and can be used in the control of oxidative stress.
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Ayed, Patricia. "Étude de l'écart à la coincidence de la macle (1012) du magnésium." Paris 11, 1986. http://www.theses.fr/1986PA112228.
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Les macles de déformation des métaux de structure hexagonale compacte peuvent se décrire comme des joints de grains en coïncidence. Leur analyse est effectuée grâce à un formalisme permettant la détermination précise de la coïncidence ou de l'écart éventuel à la coïncidence exacte au microscope électronique en transmission. La macle {1012}, la plus courante pour le système hexagonal, est analysée dans le magnésium. Des deux méthodes utilisées la méthode matricielle et la méthode des cartes de Kikuchi, seule la seconde donne une information précise sur la nature de la déviation supplémentaire à l'orientation de coïncidence exacte. Des corrélations entre ces écarts à la coïncidence de la macle {1012} et les arrangements de dislocations contenus dans les parois de macle sont établies pour une déviation ayant un caractère dominant de flexion et pour une déviation de torsion. En outre, il est montré que les deux parois de la macle peuvent avoir une nature et un comportement différent morphologie, dislocationsStudy of the deviation to the coincidence in the {1012} twin orientation of magnesium. Mechanical twins in h. C. P. Metals can be described like coincidence grain boundaries. Their analysis is carried out with a formalism giving a precise determination of the coincidence orientation or of the possible deviation to this exact coincidence by T. E. M. The usual twin {1012} in the hexagonal system is analyzed in magnesium. Among the two used methods the matrix method and the Kikuchi map method, only the second one gives precise information on the type of the supplementary deviation to the exact coincidence orientation. Correlations between these deviations to the {1012} twin orientation and the dislocation networks lying in the twin boundaries are done, either for a tilt deviation or for a twist deviation. Moreover, both twin boundaries have a different nature and behaviour orientation, morphology, dislocations
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Allerston, Patricia. "The Ring Net : ring net herring fishing on the west coast of Scotland : a documentary exhibition by Will Maclean." Thesis, University of St Andrews, 1991. http://hdl.handle.net/10023/7071.
Full textAbstract:
This dissertation focuses on The Ring Net, a documentary exhibition by the artist Will Maclean. The Ring Net is a collection of drawings, photographs and printed plans numbering more than three hundred and forty items, which was originally shown at the 'Third Eye Centre, Glasgow in 1978. It subsequently toured to various venues, mostly in Scotland, and was later bought by The Scottish National Gallery of Modern Art, Edinburgh where it is presently held. The project is based on a particular method of sea fishing which used to be practised on the West Coast of Scotland. The subject of fishing is a consistent feature in the work of Maclean, although this particular undertaking is somewhat unusual as the artist has chosen a documentary approach. The initial period of research for the project was enabled by an Edinburgh-based charitable organisation, the Scottish International Education Trust. The artist continued to work on the project for some time afterwards, and the eventual exhibition was not shown until four and a half years later. The aim of this dissertation is to look at The Ring Net in its context. The period of its making is explored in some depth, as is the showing of the project at the Third Eye Centre and the various venues included in its tour. Though the methods and media used in The Ring Net are discussed, they do not constitute the main objective of the work. More space has been devoted to the documentary aspect of the project and the effect this had on the finished result. Unpublished sources such as a series of letters from the artist to a collaborator in Kintyre have been used to some extent.
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Fountain, James R. T. "The work of modernist poet Joseph Macleod (‘Adam Drinan’) (1903 – 1984)." Thesis, University of Glasgow, 2010. http://theses.gla.ac.uk/2346/.
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This PhD thesis focuses upon the work of the neglected modernist poet Joseph Macleod (1903-1984), exploring in particular the development of his poetic style from the impacted, allusive and opaque high modernist long poem The Ecliptic (1930), through to the five books of poetry written under the pseudonym ‘Adam Drinan’: The Cove (1940), The Men of the Rocks (1942), The Ghosts of the Strath (1943), Women of the Happy Island (1944) and Script From Norway (1953). In these poems, he developed a documentary style of verse containing a strong simplicity and a socialist focus upon locality. An Old Olive Tree (1971), his final poem sequence, is entirely autobiographical, containing poems which meditate upon the friendships and familial ties which moulded his identity, and the ageing process. The causes and the implications, artistic and political, of his transformation are related to the key environments and literary relationships of his life. This exploration entails an investigation into his personal papers. The NLS archive is extensive, and in preparation for this work I undertook a first full listing of the contents of the previously uncatalogued materials. I am selective in my use of material from this vast primary resource, which contains over ten thousand items. I do, however, wish to give an indication of the literary correspondences this writer, theatre director, theatre historian and broadcaster maintained, in particular as a poet in contact with other significant poets and writers of his time. Macleod’s writing style changed over time in response to various factors, including his recognition of the importance of addressing audience and readership, as much in his work as an actor and director of the Cambridge Festival Theatre (1928-35) and in his work for the BBC as a radio announcer during the World War II, as in his poetry and prose writings. The thesis consists of six chapters, each dealing with an area of Macleod’s life and work, in chronological order. For the sake of clarity, Chapter One is an introduction giving biographical details and an overview of Macleod’s life and work, such as his early life at Rugby School, and his important and close friendship with the artist, critic and art theorist Adrian Stokes there. It also considers his time at Balliol College, Oxford, and his key friendship with Graham Greene, his time at the Cambridge Festival Theatre, and begins to examine his middle years announcing at the BBC. Chapter Two considers Macleod’s early poems and in The Rugbeian, the school’s literary journal, and his editorship with Stokes. It investigates his contributions of poems to The Oxford Outlook (edited, at the time, by Greene), as well as Oxford Poetry, 1924 and 1925. Chapter Three examines Beauty and the Beast (1927), Macleod’s book of literary observation, his first publication in book form, which appeared in the United States as well as in Britain. Chapter Four examines his major work, The Ecliptic, and his correspondence with Ezra Pound, and highlights Macleod’s views on both past and contemporary poetry. Chapter Five briefly considers his work at the Festival Theatre, as an actor, producer, director and writer, and the poetry he wrote and published for the Cambridge Festival (New Lease) Programme (1933-35) while he was editor. It also considers his interest in socialist politics. The main chapter focus is The Cove and The Men of the Rocks, the first two books published under the pseudonym ‘Adam Drinan’, considering the reasons for his adoption of a pseudonym. Chapter Six looks at the final three Drinan books, The Ghosts of the Strath (1943), Women of the Happy Island (1944) and Script From Norway (1953), and the essays he wrote at this time for Scottish journals. It examines the influence of the BBC upon his writing during his mature period. The Conclusion engages briefly with his last years in Italy and his final published collection, An Old Olive Tree (1971), and assesses the complete trajectory of his poetic journey. Two Appendices are included, the first of which contains the poet’s key correspondence, and second gives brief details of Macleod’s works, along with the publishers and editors responsible for their production. Dates of publication, and significant responses both at the time and later are included, to clarify the as yet relatively thin critical context of his work after its original reception.
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Parlangeau, Camille. "Quantification des paléocontraintes par l'analyse des macles de la calcite : nouvelle approche d'acquisition et d'inversion des données et mécaniques du maclage." Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066570/document.
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La compréhension et la simulation des mécanismes de déformation dans la croûte supérieure sont des enjeux scientifiques et techniques importants. La calcite étant un minéral commun de la croûte supérieure se déformant essentiellement par maclage sous 200 °C, c'est pour cette raison que l'on s'intéresse plus particulièrement au maclage de la calcite dans le cadre de cette thèse. L'utilisation du maclage de la calcite n'en est pas à son coup d'essai et de nombreuses méthodes d'inversions existent que ce soit pour remonter aux tenseurs des contraintes comme aux tenseurs des déformations. Cette thèse propose une nouvelle méthode d'inversion basée sur l'inversion d'Etchopar permettant de reconstruire 5 sur 6 paramètres du tenseur des contraintes avec une quantification fine des incertitudes. Cette méthode permet de détecter automatiquement l'existence d'un ou de plusieurs évènements tectoniques enregistrés par le maclage de la calcite. Un deuxième volet de la thèse consiste en l'amélioration de la méthode d'acquisition des données de macles en utilisant un EBSD (electron backscatter diffraction). En effet, l'utilisation traditionnelle de la platine universelle a des limitations techniques et amène aussi à un doute visuel sur l'appréciation du statut non-maclé de certains plans, en plus du côté long et fastidieux. Le dernier volet de la thèse consiste à déterminer le seuil de maclage de la calcite pour différentes tailles de grains à l'aide de tests mécaniques sous une presse uniaxiale. Qui plus est, le suivi en continu des déformations sur les monocristaux de calcite a permis de mettre en évidence le comportement macroscopique d'un cristal de calcite et la séquence de maclageThe understanding and modelling of deformation mechanics in the upper crust are important scientific and technical issues. The calcite is a common mineral in the upper crust and mainly deforms by twinning under 200°C. That is why we are interested by calcite twinning as part of this thesis. It is not the first time that calcite twinning is used to reconstruct paleostress or paleostrain tensors. This thesis propose a new inversion method based on the Etchecopar’s one allowing to reconstruct 5 among 6 parameters of the stress tensor with an accurate quantification of the uncertainties. This method allows to automatically detect the realness of one or several tectonic events recorded by calcite twinning. A second part of the thesis consists in the improvement of the data acquisition by using EBSD (electron backscatter diffraction). In fact, the traditional use of the universal stage has technical limitations and brings some optical doubt about the untwinned status of few planes in addition to the long and tedious side. The last part of the thesis consists in the establishing the threshold of calcite twinning for different grain sizes by mechanical tests under a uniaxial press. Moreover, the continuous monitoring of the experiments using single crystals of calcite allowed to highlight the macroscopic behavior of a single crystal and the sequence of twinning
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BRAISAZ, THIERRY. "Structure atomique des macles dans les metaux a symetrie hexagonale." Caen, 1996. http://www.theses.fr/1996CAEN2056.
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La deformation des metaux a symetrie hexagonale tels que le zinc (c/a=1,856) et le titane (c/a=1,588) entraine la formation de macles. Leurs structures atomiques ont ete identifiees a la fois theoriquement a l'aide de calculs de minimisation d'energie (relaxation) et experimentalement par microscopie electronique haute resolution. On retrouve la structure plane et symetrique decrite pour un metal ayant un rapport parametrique c/a proche de la valeur ideale (1,633). Experimentalement, une interface metastable, microfacettee, a ete observee au voisinage des defauts de macle. De plus, nous avons tout particulierement examine les marches interfaciales associees aux dislocations de macle. Nous avons propose une nouvelle nomenclature pour exprimer les vecteurs de burgers. Les vecteurs b#p#/#q expriment les vecteurs de burgers ayant une composante hors du plan d'interface et b#p#/#p les vecteurs de burgers paralleles a l'interface, ou p et q sont definis par les hauteurs respectives des marches dans le cristal 1 et le cristal 2 telles que h(1)=pd et h(2)=qd, d etant l'espacement des plans paralleles a l'interface. Nous avons mis en evidence l'origine et la stabilite de chacune des dislocations repertoriees, d'une part, grace aux parametres topologiques (vecteur de burgers et hauteur de marche) associes, et d'autre part, en considerant le flux de matiere engendre par le mouvement des dislocations. Les mecanismes d'interaction entre dislocations et de decomposition des dislocations de matrice dans le joint de macle ont ete decrits
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Jin, Yuan. "Formation des macles thermiques pour l'ingénierie de joints de grains." Thesis, Paris, ENMP, 2014. http://www.theses.fr/2014ENMP0030/document.
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Le maclage thermique est un défaut cristallographique largement discuté dans les métaux de type CFC à faible énergie de faute d'empilement. Malgré une importante littérature scientifique dédiée à ce sujet, les mécanismes expliquant précisément la formation de ces macles thermiques ne sont pas totalement élucidés à ce jour. Dans ce travail, nous avons cherché à améliorer notre compréhension de ce phénomène fondamental en métallurgie physique. Différents matériaux de type CFC (acier inoxydable 304L, nickel pur et Inconel 718) ont été considérés. Nous avons confirmé, grâce à des expériences de traitement thermique in situ couplées à des cartographies d'orientation, que la majorité des macles thermiques sont générées durant la recristallisation. De la même manière, par une expérience réalisée sur l'Inconel 718, nous avons mis en évidence que la croissance de grains pure n'était pas source de joints de macle. Par conséquent, il semble évident que les phénomènes de recristallisation et de croissance de grains ont des régimes totalement distincts associés à des mécanismes spécifiques du point de vue de la formation des macles thermiques, et doivent donc absolument être étudiés séparément. Nous avons ainsi proposé un nouveau modèle, dans lequel l'effet du signe de la courbure moyenne du front de recristallisation est pris en compte. Les influences de différents facteurs thermomécaniques, y compris le niveau de déformation, la taille de grains initiale, la température de recuit et la vitesse de montée en température, ont été étudiées à travers deux séries d'expériences. Suite à l'effet du signe de la courbure moyenne du joint de grain, nous avons proposé une méthode pour quantifier la tortuosité du front de recristallisation. Dans cette étude, nous montrons que cette quantité est corrélée à la densité de macles post-recristallisation. En sus des analyses expérimentales, des outils numériques de type champ moyen et champ complet ont également été développés dans cette étude afin de modéliser l'évolution des macles thermiques tout en tenant en compte des mécanismes physiques mis en évidence expérimentalement. Les bases d'un nouveau modèle de type champ moyen ont été proposées afin de modéliser l'évolution de la densité de macles moyenne durant le phénomène de croissance de grains. Ce modèle, dans lequel seulement un paramètre doit être identifié par des donnés expérimentales, semble mieux décrire les résultats expérimentaux obtenus pour l'inconel 718 comparé au modèle de Pande, référence en la matière. Deux méthodes implicites i.e. la méthode level-set et la méthode champ de phase ont été comparées au niveau de leurs formulations et de leurs performances numériques pour des simulations de croissance de grains anisotrope. C'est la première fois que ces deux méthodes sont comparées dans le contexte de l'utilisation de maillages éléments finis non stucturés et hétérogènes en terme de taille de maille. Une nouvelle méthodologie a été ainsi proposée dans le cadre de l'approche level-set pour simuler l'évolution de macles thermiques durant le phénomène de croissance de grains. Dans cette nouvelle méthodologie, les joints de macles peuvent être insérés dans des microstructures synthétiques. De plus, les joints de macles peuvent être distingués selon leur nature cohérente ou incohérente. Nous avons montré à travers les différentes simulations réalisées que les propriétés spéciales des joints de macles peuvent être prises en compte avec ce nouveau formalismeAnnealing twin is a crystallographic defect that is largely reported in F.C.C. metals especially those with low stacking fault energy. Despite the amount of work dedicated to the subject, the understanding of annealing twin formation mechansims is not complete in the literature. In the present work, by applying both experimental and numerical tools, we tried to have a more profound understanding of this phenomenon, which is essential to Physical Metallurgy. For this purpose, different F.C.C. Materials including 304L stainless steel, commercially pure nickel and nickel based superalloy Inconel 718 are investigated. We confirmed that annealing twins are mainly formed in the recrystallization regime, especially driven by the migration of recrystallization front into deformed regions by using in situ EBSD technique. In addition, we found in the in situ observations that there are almost no twins generated in the grain growth regime. This observation is confirmed by another grain growth experiment performed on Inconel 718. Therefore, curvature driven grain boundary migration by itself is not sufficient to generate annealing twins. A new atomistic model to explain annealing twin formation mechanism, in which the effect of migrating boundary curvature is considered, is proposed. The effects of different thermo-mechanical factors, including prior deformation level, initial grain size, annealing temperature and the heating velocity, on annealing twin formation are determined via two experiments performed on commercially pure nickel. Based on the idea of grain boundary curvature, we proposed a method to quantify recrsytallization front tortuosity. In the present study, we show evidence that this quantity is positively correlated with the twin density at the end of the recrystallization regime. In addition to experimental studies, numerical tools including both mean field and full field approaches are applied to model annealing twin evolution during grain growth by taking into account the revealed mechanisms. A basis of a new mean field model is proposed to model annealing twin density evolution during grain growth. This model, which has only one parameter to be identified, provides a better consistency with the experimental data of Inconel 718 compared to the Pande's model. Besides, full field approaches are also applied to simulate the overall microstructure evolution during grain growth. Two implicit methods i.e. the level set and the multi-phase-field methods are compared in terms of their formulations and their numerical performance in anisotropic grain growth simulations. It is the first time that these two methods are compared in the finite element context with non-structural mesh. In the present numerical context, the level set method is more suitable to describe strong anisotropy in grain boundary energy. A new methodology is thus developed in the level set framework to simulate annealing twin evolution during grain growth. This methodology, in which we can insert annealing twin boundaries into synthetic microstructures and distinguish coherent and incoherent twin boundaries, is proven to be able to counting for the strong anisotropy introduced by coherent annealing twin boundaries
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Dobek, Allison, and University of Lethbridge Faculty of Arts and Science. "Neoliberalism in small town Alberta : a look at personhood, gender, race and poverty." Thesis, Lethbridge, Alta. : University of Lethbridge, Faculty of Arts and Science, 2004, 2004. http://hdl.handle.net/10133/217.
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An in-school feeding project, Kids In Need or KIN, was introduced in the fall of 2001 to a rural community located between two First Nation's Reserves, in southern Alberta. I analyze the KIN project and its ensuing controversy as the site of struggle over the meaning of parenting. Given the predominance of neoliberalism as a discursive practice, centered on individual responsibility, the controversy generated by the KIN project reflects the central question of how to implement a program devised to assist children living with adults presumably "responsible" for their well-being. Implicitly the debate centered on particular class-based, neoconservative constructions of families, which support a gendered division of labor and were deployed in this community to reengage long standing notions about the parental deficits of Natives. This thesis explores the possible dangers, then, of the KIN project's focus on child poverty, in relation to neoliberal constructions of personhood, gender and race.vi, 124 leaves ; 29 cm.
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Cormier, Audrey M. "Regionalism in the fiction of Alistair MacLeod, Alden Nowlan, and David Adams Richards." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ65482.pdf.
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Mzumara, Macleans. "Developing an export promotion strategy for the post-conflict reconstruction of Zimbabwe / Macleans Mzumara." Thesis, North-West University, 2012. http://hdl.handle.net/10394/9802.
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The study intended to investigate whether Zimbabwe possesses realistic potential export opportunities that can lead to the sustainable reconstruction of its economy. The study was initiated on the premise that Zimbabwe is a fragile state and a post-conflict country going through reconstruction. The study also premised itself on the foundation that the current recovery efforts by Zimbabwe – although they have yielded some positive results, have still fallen short of providing sustainable economic growth without meaningful deeper reforms. Hence, this study is an attempt to provide policy makers with an alternative researched export promotion strategy with a focus on realistic potential opportunities.
The study employed two techniques, namely survey of literature and empirical investigation. The survey of literature was achieved through theoretical literature on post-conflict reconstruction. Exports were identified in the various experiences of those countries that have gone through post-conflict reconstruction and still managed to use them in their recovery process. This necessitated a thorough investigation of literature to draw a theory upon which exports promotion could rely. The major theory that was surveyed in the literature is exportled growth (ELG). The theory is based on the premise that exports influence economic growth. Empirical evidence through literature was established in the studies carried out in different countries supporting the hypothesis. The theory was seen as superior to the import substitution strategy which led many developing countries to lag behind those which adopted export-led growth policies.
The other aspect of empirical investigation was carried out through the application of the Decision Support Model (DSM). This is a scientific model that is used as a method of market selection. The model’s 4 filters were modified to include a 5th filter to specifically take into account the special circumstances of Zimbabwe. The 5th filter extension of the model provided a substantial contribution by this study to the model. A proxy of Zimbabwe’s neighbours – namely Botswana, Mozambique, Namibia, South Africa and Zambia was used to reinforce Zimbabwe’s competitiveness. This was based on the assumption that if Zimbabwe’s neighbours under similar conditions can successfully penetrate certain markets, then Zimbabwe should not find it difficult to penetrate the same markets. This empirical investigation showed that Zimbabwe does possess realistic potential export opportunities. The results identified 344 realistic export opportunities (REOs) for Zimbabwe in 17 regions, 50 countries, 13 sectors and 112 product lines. The study observed that Zimbabwe is in fact not utilising much of the REOs.
In order to enable Zimbabwe to utilise the REOs, the study developed an appropriate export promotion strategy. The export promotion strategy is based on the results obtained from empirical investigation. The export promotion strategy has sub-strategies which respond to the specific needs of individual sectors and individual markets. The study established that instead of spending resources in an unfocused manner, the meagre resources can be applied to a more focused export promotion strategy. Based on the experiences of other countries that have gone through a similar post-conflict reconstruction process and have also used the theoretical conceptual framework of the export-led growth theory, the DSM results show there are realistic export opportunities (REOs) and these may contribute towards economic growth and recovery. The study further provided recommendations on how Zimbabwe could realise realistic potential export opportunities.
This study has made a three-fold contribution. Firstly, a contribution has been made to the literature on post-conflict reconstruction and export promotion. Secondly, a significant contribution has been made by extending the Decision Support Model with a 5thfilter that also considers the supply side in the model. Finally, it has formulated an export promotion strategy, which can be applied by policy makers in Zimbabwe.Thesis (PhD (Economics))--North-West University, Potchefstroom Campus, 2013.
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Bernard, Florence. "Traduction de trois nouvelles d'Alistair MacLeod tirées de The Lost Sait Gift of Blood." Mémoire, Université de Sherbrooke, 1990. http://hdl.handle.net/11143/10340.
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Dès la parution de son recueil de nouvelles L'Amer héritage, en 1976, Alistair MacLeod a obtenu un accueil enthousiaste de la part des critiques et du milieu littéraire canadien-anglais. Ce sont là de «belles nouvelles, bien structurées, émouvantes et prenantes, écrites par l'un des écrivains les plus prometteurs d'Amérique du Nord», écrit Joyce Carol Oates sur la quatrième de couverture du recueil. Chez nos voisins du Sud, on avait déjà pressenti ce grand talent puisqu'avant la parution du recueil, deux des nouvelles de MacLeod étaient choisies pour faire partie de la collection des Best American Short Stories: «Le Bateau», en 1969, et «L'Amer Héritage», en 1975. Cela faisait de MacLeod le premier auteur canadien à être honoré de cette façon à deux reprises. Très rapidement, la nouvelle «L'Amer Héritage» est devenu un classique de la littérature canadienne-anglaise.
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Béjaud, Romuald. "Formation et extension de macles de déformation dans des nanostructures cfc : simulations numériques." Thesis, Poitiers, 2017. http://www.theses.fr/2017POIT2318.
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Depuis quelques dizaines d'années, l'élaboration de matériaux nanostructurés tend de plus en plus à se développer. En effet, ces matériaux présentent souvent des propriétés intéressantes et en particulier des propriétés mécaniques surprenantes vis-à-vis de leurs homologues sous forme massive. Les métaux nano-maclés ou nano-lamellaires par exemple, sont connus pour avoir une bonne résistance mécanique, une bonne stabilité thermique et une excellente résistance aux radiations. Au fur et à mesure que l'espacement entre les interfaces diminue, leur densité augmente de manière significative et les propriétés macroscopiques du matériau sont de plus en plus dépendantes des interactions défaut-interface. Dans ce contexte, nous avons étudié, via des simulations atomistiques, la formation de macles de déformation et les mécanismes d'interaction d'une macle nouvellement formée avec une interface préexistante (un joint de macle ou une interface entre 2 métaux), pour une configuration modèle de film mince auto-supporté. Des premiers résultats montrent l'influence de marches de surface sur le maclage, pour un cas modèle sans interface. Puis nous avons identifié un mécanisme inédit aboutissant à la formation d'une dislocation de Lomer suite à l’interaction d'une macle en formation avec un joint de macle préexistant. En faisant varier la densité de défauts de surface, nous montrons l'influence particulière d'un joint de macle sur la taille et le nombre de macles formées. Enfin, pour les systèmes bimétalliques Cu/Ag, nos résultats mettent en évidence le rôle des dislocations d'épitaxie (à l'interface) dans la nucléation et l'extension des macles ainsi qu'une influence directe du type d'interface considéré sur la propagation de ces maclesFor several decades, the elaboration of nano-structured materials tends to develop more and more. Indeed, these materials often show interesting properties, and in particular surprising mechanical properties when compared to their bulk counterparts. For example, nano-twinned or nano-layered metals are known to have ultra-high mechanical strength, good thermal stability, and very good radiation resistance. As the interface spacing decreases to the nanometer-scale, the density of interfaces increases significantly and subsequently the macroscopic properties become largely governed by the interface-defect interactions. In that context, we have studied deformation twin formation and mechanisms of interaction between a new formed twin and a preexisting interface (a twin boundary or a bimetallic interface), using atomistic simulations and a thin film model configuration. First results show the influence of surface steps on mechanical twinning, for a model system without interface. Then we identify a new mechanism leading to the formation of a Lomer dislocation, following the interaction of a newly formed twin and a preexisting twin boundary. By varying the density of surface defects, we show the particular influence of a preexisting twin boundary on twin size and number. Finally, for the Cu/Ag bimetallic system, our results highlight the role of epitaxial dislocations (at the interface) in twin nucleation and extension as well as a direct influence of the interface type in twin propagation
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Juan, Pierre-Alexandre. "Micromechanical and statistical studies of twinning in hexagonal metals : application to magnesium and zirconium." Thesis, Université de Lorraine, 2015. http://www.theses.fr/2015LORR0336/document.
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Le principal objectif de ce travail est l’investigation et la quantification de l’influence des interactions parent-macle et macle-macle sur la réponse mécanique des métaux hexagonaux, et en particulier sur celle du Mg et du Zr. Une nouvelle approche à champs moyens est tout d’abord proposée pour étudier l’interaction parent-macle. Cette dernière est déclinée en deux modèles micromécaniques à double-inclusion : un premier modèle généralisant le résultat de Tanaka-Mori aux milieux élastiques hétérogènes avec déformations libres de maclage appliqué au Mg pour du maclage primaire et secondaire, et un second modèle consistant en une extension du premier modèle à un milieu élasto-plastique appliqué à des polycristaux d’alliage de Mg subissant un maclage primaire important. Leurs résultats mettent notamment en valeur l’influence des interactions de type parent-macle sur l’évolution des contraintes internes ainsi que sur l’activation des modes de glissement et de maclage. L’influence des interactions macle-macle sur les phénomènes de nucléation et de croissance de macles est ensuite étudiée de façon statistique à partir de données EBSD extraites à partir d’un logiciel, basé sur la théorie des graphes et développé lors de la thèse. La première étude réalisée sur le Zr montre que les interactions macle-macle sont défavorables à la nucléation de nouvelles macles et que les mécanismes de croissance peuvent différer de façon conséquente d’un mode de maclage à l’autre. Une seconde étude, effectuée à partir d’échantillons d’alliage AZ31 Mg, discute des macles d’extension primaires {10-12} à faible facteur de Schmid et des double-macles {10-12}-{10-12}The objective of this thesis is to investigate and quantify the influence of parent-twin and twin-twin interactions on the mechanical response of h.c.p. metals. To study parent-twin interactions, a mean-field continuum mechanics approach has been developed based on a double inclusion topology. A first model generalizing the Tanaka-Mori scheme to heterogeneous elastic media is applied to first and second generation twinning in Mg. The model is capable of reproducing the trends in the development of backstresses within the primary twin and enables the identification of the most likely second-generation twin variants to grow in a primary twin domain. A second self-consistent model, consisting of an extension of the first one to the case of elasto-plasticity, is applied to AZ31 Mg polycrystals. The results show that deformation system activities and plastic strain distributions within twins drastically depend on the interaction with parent domains. The influence of twin-twin interactions on nucleation and growth of twins is being statistically studied from Zr and Mg electron back-scattered diffraction (EBSD) scans. A twin recognition software relying on graph theory analysis has been developed for data extraction. The results obtained from Zr EBSD maps reveal that twin-twin interactions hinder subsequent twin nucleation and that mechanisms involved in twin growth may differ for each twinning mode. A second study performed on AZ31 Mg presents statistics about low Schmid factor {10-12} tensile twins and about {10-12}-{10-12} double twins coupled with a simplified version of the Tanaka-Mori scheme generalized to heterogeneous elasticity with plastic incompatibilities
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Azzaz, Mohamed Shaker. "Étude par microscopie électronique des fautes d'empilement et des macles dans le phosphure d'indium déformé." Vandoeuvre-les-Nancy, INPL, 1991. http://www.theses.fr/1991INPL116N.
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Des monocristaux d'InP non dopé et dopé soufre (InP. S) ont été déformés en compression uni axiale, à vitesse imposée, à des températures variant de 0,35 Tf à 0,58 Tf et observée ensuite en microscopie électronique par transmission. Le résultat le plus original est l'observation de fautes d'empilement extrinsèques, fréquentes et étendues, et apparemment simples, pour les deux types de matériau. Dans InP. S uniquement, la déformation a crée des macles de différentes tailles dont l'épaisseur peut atteindre environ 5 microns. Ces macles apparaissent pour des faibles déformations, dès la limite d'élasticité. Ils leurs sont associés des accidents sur les courbes contrainte-déformation. Nous n'avons pas trouvé l'explication satisfaisante pour tous les cas de figures observés. Néanmoins les configurations des micro macles suggèrent l'existence d'un mécanisme de pôles suivant la description de PIROUZ plutôt que celle de VENABLES. En effet nous n'avons pas observé de partielles de Frank et les macles sont situées dans le plan de glissement sollicité
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Vasil, Christina Jane. "Ann-Marie MacDonald in the context of Hugh MacLennan and Alistair MacLeod, gender formation in three Cape Breton writers." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape15/PQDD_0026/MQ33830.pdf.
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Butler, Tanya L. "The significance of ancestral islands, Highland Scottish and regional identity in the works of Margaret Laurence and Alistair Macleod." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape9/PQDD_0004/MQ45364.pdf.
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Ayed, Patricia. "Etude de l'écart à la coïncidence de la macle (10 ̄12) du magnésium." Grenoble 2 : ANRT, 1986. http://catalogue.bnf.fr/ark:/12148/cb37595575j.
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Ouarem, Abdelouahab. "Comportement mécanique et évolutions microstructurales sous compression quasi-statique et dynamique de polycristaux CFC et HC : effet de la taille des grains." Paris 13, 2012. http://scbd-sto.univ-paris13.fr/intranet/edgalilee_th_2012_ouarem.pdf.
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Le présent travail est consacré à l'analyse de l’effet de la vitesse de déformation et de la taille des grains sur les mécanismes de plasticité activés lors de la déformation plastique dans deux types de matériaux polycristallins: (i) le zinc (Zn), de structure hexagonale compacte, et ayant des tailles de grains dans le domaine micrométrique (300 µm) et dans le domaine des grains ultrafins (200 nm). Ces matériaux sont déformés en compression quasi-statique et dynamique (vitesse de déformation atteignant 10⁵ s⁻¹) à l’aide de bars de Hopkinson (DIHPB) ; (ii) le nickel (Ni) électrodéposé à grains fins, de structure cubique à faces centrées ayant une taille moyenne de grains de l’ordre de 4 µm, également déformé en compression dynamique (DIHPB). Des différences significatives en termes de micro-mécanismes de déformation dans les deux régimes ont été mises en évidence: (i) pour des faibles vitesses de déformation et jusqu'à ~10² s⁻¹, la déformation a lieu principalement par glissement des dislocations à la fois dans Ni et dans Zn à grains nanométriques. Toutefois, un maclage important est observé dans le cas des échantillons Zn à grains micrométriques, indiquant ainsi un effet de la taille des grains sur le maclage; (ii) Dans le régime dynamique (> 10³ s⁻¹) la déformation plastique induit une augmentation de la température dans les échantillons (Ni ou Zn). Cette augmentation de la température est suffisamment importante pour induire à son tour la restauration et/ou la recristallisation dynamique. Comme conséquence, deux phénomènes sont observés en fonction du matériau: pour Ni, la microstructure et les propriétés mécaniques résultant sont similaires à celles de l'état initial, dominé par des macles de recuit et des grains équiaxes et orientés de façon aléatoire. Pour Zn un affinage important de la taille des grains est observé (de 300 µm à 6 µm) qui s’accompagne au passage de l’inhibition du phénomène de maclage. Pour clarifier ce point, des investigations complémentaires ont été effectuées sur des échantillons de Ti de pureté commerciale (CP-Ti) à grains micrométriques dans les deux régimes quasi-statique et dynamique. Les résultats montrent que le maclage est ici le principal mécanisme de déformation. La densité des macles est d’autant plus élevée que la vitesse de déformation est importante et les grains plus gros. Ces résultats confirment l’influence l'effet de la taille des grains sur le maclage mécanique dans les matériaux HC. Par contre, il a été observé que l'effet de la vitesse de déformation sur le maclage dans le régime dynamique est différent selon qu’il s’agisse de Zn ou de Ti. Dans le premier cas, il est probable que le faible niveau du rapport T/T f joue un rôle clé, en induisant le recristallisation dynamique dans les conditions expérimentales étudiées iciThe present work is devoted to the analysis of the strain rate and grain size effects on the deformation mechanism activated during plastic deformation of two polycrystalline materials: (i) zinc (Zn), a crystal with hexagonal compact packing structure, having grain size in the micro and ultrafine grain ranges (~ 300 µm and 200 nm, respectively), loaded under quasi-static and dynamic compression conditions, up to a strain rate of ~ 10⁵ s⁻¹ (by use of a Direct Impact Hopkinson Pressure Bars (DIHPB); (ii) electrodeposited nickel (Ni), a face-centered cubic structure with grain size of 5 µm deformed in compression under dynamic conditions using DIHPB. Significant differences in terms of micro-mechanisms of deformation in the two regimes were found: (i) At lower strain rates, up to ~ 10² s⁻¹, dislocation-based plasticity was observed in both Ni and Zn. Extensive twinning occurred only in the case of micrometer grain-sized Zn, indicating a grain size dependence of twinning; (ii) In the dynamic regime (> 10³ s⁻¹) plastic deformation induced a significant increase of the temperature within the samples. This increase of temperature was significant enough to induce recovery and/or dynamic recrystallization. As consequence two phenomena were observed depending on the structure under investigation: for Ni, the resulting microstructure and mechanical properties were similar to that of the initial state, dominated by annealing twins and equiaxed and randomly oriented grains. For micro-grained Zn a tremendous grain refining was found. As a consequence, twinning was inhibited. To clarify this point, additional investigations were carried out on coarse-grained CP-Ti deformed in both quasi-static and dynamic regimes. It was found that twinning was the main deformation mechanism. Indeed, the larger the strain rate and grains size, the larger the twin density. On the one hand, these results clearly demonstrate the grain size effect on the occurrence of mechanical twinning in HCP materials. On the other hand, the effect of the strain rate on twinning was found to depend on the material under investigation. Compared to Ti, the lower homologous temperature T/T m of Zn probably plays a key role, as it may induce dynamic recovery/recrystallization as far as the present experimental conditions are concerned
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Sirindil, Abdullah. "Z-modules et alliages intermétalliques." Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066484/document.
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Le présent travail de thèse se propose de profiter de la description cristallographique à N dimensions pour rediscuter les structures des alliages métalliques périodiques dont les atomes sont situés sur un sous-ensemble ordonné d’un Z-module — c’est-à-dire sur des positions qui sont des combinaisons linéaires entières de N>3 vecteurs arithmétiquement indépendants— exemplifiés par les quasicristaux et les phases approximantes. La description cristallographique à N dimensions permet ainsi de révéler des symétries supplémentaires, cachées dans l’espace physique, susceptibles d’engendrer de nouveaux types de défauts, dits défauts de module, dans les alliages métalliques périodiques dont les atomes se localisent sur un Z-module non trivial dans l’espace direct. Ces défauts correspondent aux opérations de symétrie interne du Z-module qui sont perdues lors de la projection rationnelle dans l’espace physique en raison de la périodicité de l’alliage. Ce sont des macles, des défauts de translations et les dislocations qui les bordent et que nous désignons par dislocations de modules pour les différencier des usuelles dislocations de réseau. Elles apparaissent comme des dislocations partielles bordant une ou plusieurs fautes d’empilement. Des dislocations particulières peuvent exister avec des vecteurs de Burgers ayant une composante nulle dans l’espace physique. Ces dislocations, que nous appelons dislocations scalaires, n’engendrent aucun champ de contrainte et ne sont sensibles à aucun champ de déformation. La phase orthorhombique NiZr de symétrie Cmcm a une maille cristalline dont tous les atomes sont situés sur une fraction d’un même Z-module pentagonal ; elle, est à ce titre, parfaitement descriptible à 5 dimensions. A parti de cette analyse, nous avons prédit l’existence de nouveaux défauts tels que les macles quinaires et défauts de translations, tous observés et confirmés par nos observations en microscopie électronique haute résolution HREM et STEM-HAADFThe present work is an attempt to take advantage of the N-dimensional crystallographic description to rediscuss the structures of periodic metal alloys whose atoms are located on an ordered subset of a Z-module — positions that are integer linear combinations of N> 3 arithmetically independent vectors — like those encountered in quasicrystals and approximants. This N-dimensional crystallographic description makes it possible to reveal hidden symmetries in periodic metallic alloys, that can generate new types of possible defects by symmetry breaking during the projection in the physical space. Thus, in addition to the usual defects due to a local breaking of periodicity, these alloys may contain new defects corresponding to internal symmetry operations of the Z-module which are lost due to the periodicity of the alloy. These defects are twins, translation defects and dislocations that border them and that we refer to as dislocations of modules to differentiate them from the usual network dislocations and which appear as partial dislocations bordering one or more stacking faults. Particular dislocations may exist with Burgers vectors having a null component in the physical space. These dislocations, which we call scalar dislocations, generate no stress field and are not sensitive to any deformation field. The orthorhombic phase of NiZr has a crystal structure the atoms of which are located on a fraction of the pentagonal Z-module and is therefore fully describable at 5 dimensions. We can thus describe new defects such as quinary twins, but also defects of translations that all keep the Z-module invariant. All these defects have indeed been observed and recognized by high resolution electron microscopy (HREM and STEM-HAADF)
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Quarez, Éric. "Nouveaux oxydes de métaux de transition à valences élevées obtenus par électrosynthèse : empilements de couches, macles et structures composites." Lille 1, 2002. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/2002/50376-2002-137.pdf.
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Par électrosynthèse en milieu soude fondue, des cristaux maclés de Ba2NaM2O6 ont été obtenus. La symétrie est orthorombique et la structure est constituée de blocs hexagonaux décalés et séparés par des atomes de baryum. Une matrice de macle traduisant la rotation de 120° autour de l'axe c de trois domaines est introduite avec succès dans les affinements structuraux. La macle est une macle polysynthétique et les défauts sont localisés au niveau des couches de baryum. L'étude des systèmes Ba - Ru/Mn - Na - O en présence d'un élément pentavalent a permis la préparation par électrosynthèse de quatre nouvelles phases de structure pérovskite hexagonale ou dérivée. La famille Ba6M2Na2X2O17 est formée de 12 couches (c'cchcc)2. Ba5Ru3Na2O14 est constitué de 10 couches (c(cc')ch)2. Deux transitions structurales ont été caractérisées à basse et haute températures modifiant le bloc (cc'). Ba5MnNa2V2O13 résulte d'un empilement 15 R (ccc'cc)3. Les études électriques et magnétiques des échantillons monocristallins ou pulvérents préparés par réaction à l'état solide sont également rapportées. Enfin, trois monocristaux ont été étudiés par diffraction des rayons X. Ces phases hexagonales sont caractérisées par deux sous réseaux de paramètres c différents. Les structures sont formées de colonnes parallèles à l'axe c et constituées d'une séquence octaèdre différente selon la valeur de x. Les affinements structuraux sont réalisés par un traitement classique et confirment les structures déduites du formalisme de super espace.
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Marzouki, Mohamed Amine. "Group-theoretical investigation of the structural basis for the formation of twinned crystals." Thesis, Université de Lorraine, 2015. http://www.theses.fr/2015LORR0102/document.
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Le travail de cette thèse porte sur les raisons structurales derrière la formation de cristaux maclés. Ce travail ouvre une voie pour un futur développement de protocoles de synthèse afin de réduire l'occurrence de macles. La motivation de cette étude est que la présence de macles affecte négativement les propriétés physico-chimiques des matériaux d'intérêts technologiques et réduit aussi la qualité des données expérimentales sur lesquelles se fonde l'analyse structurelle. Ce dernier problème est particulièrement sensible dans le cas de cristaux ayant des paramètres de maille importantes, comme les macromolécules biologiques. Les principes de symétrie responsables du phénomène de maclage dans le cas d’une macle de transformation ou d'origine mécanique sont bien connues. En revanche dans le cas d’une macle de croissance, le maclage est toujours considéré comme un accident lié aux conditions aléatoires de croissance cristalline où à la cinétique, plutôt qu'à la thermodynamique. Une approche générale connue comme la « théorie réticulaire des macles » a été développée depuis le XIXe siècle, fondée sur l'existence d'un sous-réseau commun aux cristaux maclés, qui donne les conditions nécessaires pour l'apparition d'une macle. Cette approche est cependant insuffisante pour déterminer la différence entre les macles avec le même degré de chevauchement des réseaux mais montrant une fréquence d'occurrence assez différente. Une approche structurale, fondée sur l'analyse de la symétrie propre des orbites cristallographiques a été proposée il y a plus d'un demi-siècle (Donnay et Curien, 1960), mais est restée à l'état embryonnaire, malgré une certaine reprise récente (Nespolo et Ferraris, 2009). En outre, l'idée qu'une interface commune aux cristaux maclés puisse contenir une opération reliant ces individus a été proposée (Holser, 1958) mais n'a jamais été portée à un plein développement. Dans cette thèse, nous présentons un développement algébrique de ces idées. Nous montrons que les conditions structurales nécessaires pour la formation d'une macle de croissance peuvent être formulées en se basant, notamment, sur la symétrie propre des orbites cristallographiques et sur le groupe sous-périodique de la couche transversale donnant la symétrie d'une couche commune. L'analyse détaillée dans cette thèse de trois macles fréquentes démontre une corrélation claire entre le degré de restauration de la structure par l'opération de maclage et la fréquence d'occurrence des macles. Un exemple négatif, à savoir une macle hypothétique dont on pourrait prévoir la formation sur la base de la théorie réticulaire a aussi été analysé. Le fait que cette macle n'ait jamais été observée, en raison d’une faible restauration de la structure qui serait produite par l'opération de macle, confirme le bien fondé de l'approche. Nous nous attendons à ce que la généralisation de l'approche présentée dans cette thèse fournisse une procédure semi-automatique pour prévoir la probabilité de formation d'une macle. Cela permettrait aux personnes travaillant dans la synthèse cristalline démoduler la fréquence de maclage. Le procédé fait appel à la modification de la morphologie du cristal pour une plus grande exposition et le développement des faces cristallines qui présentent une interface défavorable pour le maclageThis thesis addresses the structural rationale behind the formation of growth twins, with the purpose of opening a route to the future development of synthesis protocols to reduce the occurrence frequency of twinning. The reason for this effort is that twinning affects negatively the physico-chemical properties of materials and biomaterials of technological interests and reduces the quality of the experimental data on which the structural investigation is based. While on the one hand the reasons for twinning in transformation and mechanical twins are well understood, in the case of growth twins twinning is still seen as an accident linked to aleatory conditions where kinetics, rather than thermodynamics, plays a principal role. A general approach known as the reticular theory of twinning has been developed since the XIX century, based on the existence of a sublattice common to the twinned crystals, which gives the minimal necessary conditions for the occurrence of a twin. This approach is, however, insufficient to discriminate between twins with the same degree of lattice overlap but showing a fairly different occurrence frequency. A structural approach, based on the analysis of the eigensymmetry of the crystallographic orbits building a crystal structure was proposed more than half a century ago (Donnay and Curien, 1960) but remained at an embryonic state, despite some recent revival (Nespolo and Ferraris, 2009). Also, the idea that a slice common to the twinned individuals may contain an operation mapping these individuals was proposed (Holser, 1958) but never brought to a full development. In this thesis, we present a full development of these ideas and show that the structurally necessary conditions for the formation of a growth twin can be described on the basis of the eigensymmetry of the crystallographic orbits and on the sectional layer group giving the symmetry of the common slice. The detailed analysis of three well-know twins demonstrates a clear correlation between the degree of structural restoration by the twin operation and the occurrence frequency of the twins. The analysis of a negative example, i.e. of a hypothetical twin which one would expect on the basis of the reticular theory but has never been observed, strengthens the evidence of this correlation, because of the low structural restoration one would observe in that twin. We expect that the generalisation of the approach presented in this thesis through a semi-automatic procedure will provide crystal growers with a powerful tool to modulate the occurrence frequency of twinning through a modification of the crystal morphologies towards a larger exposure and development of crystal faces which represent an unfavorable interface for twinning
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Jones, Andrew Michael. "Continuation, breadth and impact of evangelicalism in the Church of Scotland, 1843-1900." Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/31384.
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This thesis examines the nature and role of evangelicalism within the Established Church of Scotland between the Disruption of 1843 and the end of the nineteenth century. It focuses on three prominent evangelical clergymen within the Church of Scotland and three contemporary religious periodicals. The thesis argues that the Church of Scotland developed theologically, socially, and culturally away from the conservative Calvinism of the Westminster Confession of Faith toward a more inclusive theology, while still maintaining typical evangelical views on missions, conversion, atonement, and the Bible. It further argues that the increasingly liberal evangelical movement contributed greatly to the post-Disruption recovery of the Church of Scotland. Chapter One considers the role of the evangelical Middle Party and especially the Edinburgh clergyman William Muir (1787-1869) in the initial recovery of the Establishment following the secession of a third of the clergy and nearly half her members in 1843. Chapter Two discusses the work of the Church's missionary organizations in the wake of Disruption, drawing on the reports of the Church's Home and Foreign Missionary Record. Chapter Three examines the life of Norman MacLeod (1812-1872), minister of the Barony Church, Glasgow, and argues that his Romantic sympathies greatly influenced the confessional liberalization of the Church. Chapter Four shows how the influence of this more theologically liberal evangelicalism was further advanced by MacLeod's religious periodical Good Words. Chapter Five focuses on Archibald Hamilton Charteris (1835-1908), a parish minister and later university professor whose efforts to democratize evangelistic and social work and encourage spiritual life strengthened and revitalized the Church at large. Finally, Chapter Six examines the Church of Scotland periodical begun by Charteris - Life and Work magazine - and considers its theological, spiritual, and social impact on the Church between 1879 and the turn of the new century.
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Fausty, Julien. "Towards the full field modeling and simulation of annealing twins using a Finite Element Level Set method." Thesis, Université Paris sciences et lettres, 2020. http://www.theses.fr/2020UPSLM022.
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Le dimensionnement des disques de superalliage base nickel dans les moteurs d’avion est un processus complexe et critique pour le bon fonctionnement du transport aérien. L’amélioration continue des performances de ces composants doit assurer la bonne tenue du moteur dans des conditions mecaniques et thermiques extrêmes. Un des aspects les plus importants dans la genèse de ces produits est l’état microstructural de la matière. Les ingénieurs qui développent ces turbines ont donc un besoin spécifique pour des modèles capables de prédire les évolutions microstructurales pendant le forgeage. Ce travail a pour but d’améliorer les approches numériques de type Elément Finis - Level Set appliquées à l’ évolution des microstructures métalliques en enrichissant la description des joints de grains. L’enrichissement de la représentation des joints de grains est nécessaire afin de prendre en compte des joints particuliers - comme les joints de macles - qui sont observés en très grand nombre dans les superalliages forés. Cette activité vise particulièrement à incorporer l’effet des énergies arbitraires des interfaces cristallines dans les modèles de migration de joints de grains. Les modifications aportées à la méthode sont à la fois numériques et mathématiques. En incluant des termes supplémentaires dans l’expression de la vitesse de migration de l’interface, cette étude montre, par la simulation de cas analytiques et non-analytiques, que l’approche est capable de simuler un éventail de phénomènes. A la fois l’effet de l’ancrage dû à l’orientation et le moment sur les joints multiples sont mis en évidence. La méthode donne aussi des résultats plus fiables sur la simulation des joints avec des propriétés particulières comme les joints de maclesThe design of nickel based superalloy disks in an industrial setting is a stringent process which must produce critical components of the aircraft engine. Improving these components is no small feat given the extreme mechanical and thermalconstraints endured by these types of parts. One of the most important aspects of the design is the microstructure of the unerlying material. As such, the engineers who design these machines have a specific need for models capable of predicting microstructural evolution in metallic materials during the forging process. This work aims to improve on the existing Level Set Finite Element framework for microstructural evolution by including enriched descriptions of grain boundaries. These enriched characterizations are needed in order to take into account special boundaries - such as the twin boundary - which can be observed in great number in forged superalloys. This effort is concentrated on integrating arbitrary values for the grain boundary energy density into the numerical models.This enhancement of the model lies not only in the numerical aspects but also in the underlying mathematical formulation. By including supplemental terms in the expression of the velocity of a migrating grain boundary, this investigation has found, using analytical and non-analytical benchmarks, that the new approach is able to take into account a host of phenomena. Evidence of both orientation pinning and torque applied to triple junctions has been found in virtually annealed polycrystals. Also, the model has proven to be more capable of taking into account the singular behavior of the twin boundary then previous iterations of the method
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SANFILIPPO, STEPHANE. "Effets des plans de macles sur les propriétés physiques du supraconducteur YBa2Cu3O(7-(delta) : étude sur des échantillons massifs texturés monodomaines." Université Joseph Fourier (Grenoble), 1997. http://www.theses.fr/1997GRE10300.
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Par quatre methodes de mesures, mesures de courant critique de transport, mesures d'aimantation, mesures de resistivite, et mesures de diffusion de neutrons, un effet important des plans de macles (tb) sur les proprietes supraconductrices d'echantillons d'yba#2cu#3o#7#-#x textures monodomaines est mis en evidence. Les proprietes etudiees sont essentiellement celles le long de l'axe c, avec un champ b evoluant dans les plans ab et faisant un angle variable avec une direction de tb. A t = 77k, l'ancrage des vortex par les plans de macles se traduit pour b 1t par des pics de densite de courant critique selon c (j#c) lorsque est inferieur a un angle critique t8-10. Pour b < 1t, j#c est isotrope car l'ancrage est completement domine par les plans de macles. L'angle d'accommodation devient maximal (t45). Ceci est compatible avec un reseau de vortex qui se decompose en deux sous reseaux, chacun piege par une direction de plans de macles. De plus lorsque b tb, le courant critique suivant c est insensible a l'intensite du champ magnetique jusqu'a 8t. Les plans de macles pourraient induire une supraconductivite heterogene : a forts champs, le courant critique serait domine par le courant circulant pres des tb. La supraconductivite et les proprietes de piegeage apparaissent heterogenes dans nos echantillons des que t < t#l#o#c = 87 k et b > 3t. Pres de t#c, les plans de macles localisent les vortex dans l'etat liquide. Les courbes r() et r(b) indiquent une reduction de resistivite importante lorsque < t. Cet effet se manifeste jusqu'a des champs de 20t. La localisation augmente la coherence de phase dans la direction de b et minimise le depiegeage thermique. Lorsque le piegeage est domine par les defauts etendus, le liquide pourrait geler en un verre appele <<<>verre de bose<>>>. Ceci se traduit en aimantation par une augmentation de la ligne d'irreversibilite lorsque < t et t < t#l#o#c. Les mesures de diffusion de neutrons a 4 k confirment que pour b < 1t, les vortex s'adaptent au reseau de plans de macles et forment un reseau carre lorsque b est suivant l'axe c. Il devient hexagonal pour un angle de desorientation eleve, autour de 50. Les preuves que nous apportons de l'influence des plans de macles sur les proprietes supraconductrices d'ybacuo indiquent que la maitrise de ces defauts au cours de la synthese, pourrait etre importante en vue de certaines applications futures.
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Pauchet, Morgan. "Application of the derived crystal packing model to molecular crstals grown in solutions or in gels." Rouen, 2007. http://www.theses.fr/2007ROUES056.
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The Derived Crystal Packing (DCP) model has been partly automated. The docking step can be handled by two computer program. They are tested on two couples of enantiomer / racemic compound to underline their structural similarities. The limits of the model are also discussed. A second part of the study is devoted to the experimentation of the crystallization in gel. This technique is tested with the gel precursor Tetramethoxysilane on several organic compounds. Different methods for the crystallization are described. In addition, a theoretical as well as experimental study is carried out on (±) modafinil and covers the two aforementioned themes. The first experimental data allowed the DCP model to predict the crystal structure of the form III, starting from that of form I. Subsequent structural comparisons pointed toward the extensive similarities between the two forms: they share common (001) slices. The possibility of defaults such as twinning is thus suggested. The application of the crystallization in gel to (±) modafinil yielded single crystals of form III and allowed the confirmation of the predicted structure. Careful examination of other grown crystals showed the occurrence of twinning among (±) modafinil form I crystals. The twin law was solved: a stacking fault of (001)form I leading to a form III like interface. Additional experiments on twin crystals raised the question of the structural purity of (±) modafinil form I: several twinned crystals underwent a partial dissolution of lamellar domains which could account for the presence of form III (metastable) into form I (stable), or multitwinningLe modèle appelé "Derived Crystal Packing" a été en partie automatisé. L'étape de docking peut être traitée grâce à deux programmes informatiques. Ils sont testés sur deux couples d'énantiomère / composé racémique afin de souligner leur similitudes structurales. Les limites du modèle sont également discutées. Une seconde partie de l'étude est consacrée à l'expérimentation de la cristallisation en gel. Cette technique est testée avec le précurseur Tétraméthoxysilane sur plusieurs composés organiques. Différentes méthodes de cristallisation sont décrites. Par ailleurs, une étude structurale et expérimentale est conduite sur le (±) modafinil. Les données expérimentales initiales ont permis l'application du modèle DCP et la prédiction de la structure cristalline de la forme III à partir de celle de la forme I. La comparaison des structures révèle les nombreuses similitudes structurales des deux formes: elles présentent des tranches (001) communes. La possibilité de défauts tels que le maclage est mise en avant. L'application de la cristallisation en gel au (±) modafinil a conduit à l'obtention de cristaux de forme III et a ainsi permis de confirmer la structure prédite. L'observation minutieuse des autres cristaux obtenus montre la présence de macles parmi les monocristaux de forme I. La loi de macle a été résolue: il s'agit d'une faute d'empilement de tranches (001)forme I conduisant à une interface de forme III. D'autres expériences sur les cristaux maclés ont soulevé la question de la pureté structurale du (±) modafinil forme I: plusieurs cristaux maclés ont subi une dissolution partielle de domaines lamellaires qui pourraient s'expliquer par la présence de forme III (métastable) dans la forme I (stable), ou de multi-maclage
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Batisteti, Caroline Belotto [UNESP]. "Os estudos de Avery, Macleod e Mccarty e a idéia do DNA como responsável pela hereditariedade: interpretações historiográficas e apontamentos para o ensino de biologia." Universidade Estadual Paulista (UNESP), 2010. http://hdl.handle.net/11449/90888.
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Um dos momentos históricos interessantes no estabelecimento da Biologia Molecular diz respeito às pesquisas realizadas por Avery, MacLeod e McCarty, que indicaram que a natureza química do princípio transformante bacteriano era o DNA. A nosso ver, esse episódio pode ser explorado do ponto de vista histórico, e assim fornecer elementos relevantes para o Ensino de Ciências. Em relação à perspectiva histórica, embora os estudos de Avery e colaboradores sejam atualmente considerados referência no estabelecimento de relações entre DNA e hereditariedade, há na literatura apontamentos sobre a provável não aceitação imediata desses pela comunidade científica da época (1944). Assim, o objetivo da presente pesquisa foi investigar, por meio da análise de fontes primárias, como artigos, documentos e correspondências que envolvem Avery e colaboradores, os motivos para a resistência inicial aos resultados de seus trabalhos. Dentre as razões levantadas, podemos mencionar dúvidas de cunho técnico, que indicavam a presença de proteínas nos preparados utilizados por Avery e colaboradores, a suposta timidez de Avery e a idéia de sua proposta ter sido cientificamente prematura. Outra razão, que aparentemente, abrange um maior número de aspectos envolvidos no processo de construção do conhecimento em questão, refere-se à hipótese de que a idéia do DNA como responsável pela hereditariedade encontrou dificuldades em ser aceita, pois, foi produzida e apresentada inicialmente fora da área de domínio da temática de interesse, no caso, a Genética. Acerca da utilização do episódio histórico em questão no Ensino, essa se justifica, pois possibilita a observação de diversos elementos que caracterizam e estão envolvidos na produção científica, como por exemplo: implicações metodológicas, subjetividade dos indivíduos, coletividade...
One of the interesting historical moment on the establishment of Molecular Biology is related to Avery, MacLeod and McCarty’s research, which indicated that the chemical nature of the transforming principle in bacteria was DNA. In our view, this episode can be explored from a historical perspective, and thus provide relevant information to the Teaching of Science. Regarding the historical perspective, although Avery and his colleague’s studies are now considered landmark in the establishment of relations between DNA and heredity, in literature there are notes on the probable immediate rejection of this by the scientific community of that time (1944). The objective of this research was to investigate, through analysis of primary sources such as articles, documents and correspondence involving Avery and his colleagues, the reasons for the initial resistance to the results of their work. Among the reasons raised, we can mention technical-doubt, which indicated the presence of protein in the preparations used by Avery and his colleagues, the alleged Avery’s timidity and the idea of his proposal was scientifically premature. Another reason, which apparently includes a greater number of issues involved in building the knowledge in discussion, refers to the hypothesis that the idea of DNA as responsible for heredity found difficulties to be accepted, because it was produced and presented initially outside of Genetics field. As far as use of the referred historical episode in Education or in Teaching of Biology, this is justified because it enables the observation of several elements that characterize and are involved in scientific research, such as: methodological implications, the subjectivity of individuals, collective production of knowledge, social influences (hostility), the impact of the journal in which they release a specific publication, ... (Complete abstract, click electronic access below)
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Batisteti, Caroline Belotto. "Os estudos de Avery, Macleod e Mccarty e a idéia do DNA como responsável pela hereditariedade : interpretações historiográficas e apontamentos para o ensino de biologia /." Bauru : [s.n.], 2010. http://hdl.handle.net/11449/90888.
Full textAbstract:
Resumo: Um dos momentos históricos interessantes no estabelecimento da Biologia Molecular diz respeito às pesquisas realizadas por Avery, MacLeod e McCarty, que indicaram que a natureza química do princípio transformante bacteriano era o DNA. A nosso ver, esse episódio pode ser explorado do ponto de vista histórico, e assim fornecer elementos relevantes para o Ensino de Ciências. Em relação à perspectiva histórica, embora os estudos de Avery e colaboradores sejam atualmente considerados referência no estabelecimento de relações entre DNA e hereditariedade, há na literatura apontamentos sobre a provável não aceitação imediata desses pela comunidade científica da época (1944). Assim, o objetivo da presente pesquisa foi investigar, por meio da análise de fontes primárias, como artigos, documentos e correspondências que envolvem Avery e colaboradores, os motivos para a resistência inicial aos resultados de seus trabalhos. Dentre as razões levantadas, podemos mencionar dúvidas de cunho técnico, que indicavam a presença de proteínas nos preparados utilizados por Avery e colaboradores, a suposta timidez de Avery e a idéia de sua proposta ter sido cientificamente prematura. Outra razão, que aparentemente, abrange um maior número de aspectos envolvidos no processo de construção do conhecimento em questão, refere-se à hipótese de que a idéia do DNA como responsável pela hereditariedade encontrou dificuldades em ser aceita, pois, foi produzida e apresentada inicialmente fora da área de domínio da temática de interesse, no caso, a Genética. Acerca da utilização do episódio histórico em questão no Ensino, essa se justifica, pois possibilita a observação de diversos elementos que caracterizam e estão envolvidos na produção científica, como por exemplo: implicações metodológicas, subjetividade dos indivíduos, coletividade... (Resumo completo, clicar acesso eletrônico abaixo)Abstract: One of the interesting historical moment on the establishment of Molecular Biology is related to Avery, MacLeod and McCarty's research, which indicated that the chemical nature of the transforming principle in bacteria was DNA. In our view, this episode can be explored from a historical perspective, and thus provide relevant information to the Teaching of Science. Regarding the historical perspective, although Avery and his colleague's studies are now considered landmark in the establishment of relations between DNA and heredity, in literature there are notes on the probable immediate rejection of this by the scientific community of that time (1944). The objective of this research was to investigate, through analysis of primary sources such as articles, documents and correspondence involving Avery and his colleagues, the reasons for the initial resistance to the results of their work. Among the reasons raised, we can mention technical-doubt, which indicated the presence of protein in the preparations used by Avery and his colleagues, the alleged Avery's timidity and the idea of his proposal was scientifically premature. Another reason, which apparently includes a greater number of issues involved in building the knowledge in discussion, refers to the hypothesis that the idea of DNA as responsible for heredity found difficulties to be accepted, because it was produced and presented initially outside of Genetics field. As far as use of the referred historical episode in Education or in Teaching of Biology, this is justified because it enables the observation of several elements that characterize and are involved in scientific research, such as: methodological implications, the subjectivity of individuals, collective production of knowledge, social influences (hostility), the impact of the journal in which they release a specific publication, ... (Complete abstract, click electronic access below)
Orientador: João José Caluzi
Coorientador: Elaine Sandra Nicolini Nabuco de Araujo
Banca: Maria Elice Brzezinski Prestes
Banca: Ana Maria de Andrade Caldeira
Mestre
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Selby, Sharon Dawn. "Myth, memory, and narrative : (re)inventing the self in Canadian fiction." Thesis, University of Edinburgh, 2012. http://hdl.handle.net/1842/6318.
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In this dissertation, I examine how the themes of memory, storytelling, and the construction of narrative identity develop in the works of Canadian authors Alistair MacLeod, Michael Ondaatje, and Jane Urquhart. As a means of delving more deeply into these themes, I focus on the specific narrative strategies that all three writers employ in the expression of the relationship between the individual and his/her community, as well as between physical and psychological realities. For the narrative voices in these authors’ works—given the different ways they envision and encode communal identity as constitutive of subjectivity—the past is inextricably embedded in the present. As they construct and record unfolding experience, a wider cultural history is written over with personal connections and significance. In the works of each of these authors, the act of telling stories (re)shapes people and events for the audience: speakers reform and reconstitute their experiences, allowing them both to rewrite the past and be haunted by it. Storytelling becomes an existential act in which personal landscapes are invested with structures of feeling that transcend local significance yet are manifested in everyday connections between ordinary people, and in daily (often unrecognized) struggles and acts of heroism. This includes a study of the means through which psychological evolution and trauma can be depicted. I also discuss how stylistic techniques such as fragmentation, repetition, self-reflexivity, and literary allusion function within these narratives. This aspect of my investigation provides the opportunity to engage more fully with the body of literary research that has already been produced on these authors.
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Gerber, Philippe. "Etude des liens entre hétérogénéités de déformation et mécanismes de recristallisation. Application au cuivre et ses alliages." Paris 13, 2002. http://www.theses.fr/2002PA132027.
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Les liens entre hétérogénéités de déformation et recristallisation statique sont étudiés dans le cuivre et ses alliages. Dans le cuivre, un seuil de déformation (laminage à froid de 90 %) est mis en évidence par mesures des textures globales. En dessous de cette valeur, la texture de recristallisation est dispersée. Pour une valeur égale ou supérieure, la texture Cube {100}<001> est obtenue. L'ajout de zinc provoque une distribution des orientations plus dispersée, en partie due au maclage de déformation, provoquant la production d'un ensemble d'orientations possédant un potentiel germination et croissance. La confrontation des mesures expérimentales effectuée sur le cuivre pour deux taux de déformation( =70 % et =90 %) permet d'évaluer l'influence du taux de déformation sur la recristallisation. Les mesures d'énergie stockée montrent qu'une différence minimum entre les orientations C {112}<111>et/ou S{123}<634>et Cube est vitale pour engendrer une texture Cube. Une restauration des grains Cube au tout début de la recristallisation est observée pour ces deux matériaux. Par mesures EBSD dans le cuivre =70 %, nous montrons qu'une germination intergranulaire prend place dans les zones de fortes hétérogénéités de déformation, conduisant à diperser la texture. Dans le cas du matériau =90 %, cette germination n'est pas effective. Cependant, après restauration au sein de bandes de transition Cube/G {011}<100> (voisines de grains déformés orientés C et/ou S) une germination et une croissance rapides de l'orientation Cube ont lieu. Nous pouvons ainsi parler de germination et croissance orientées. Une simulation Monte-Carlo permet de reproduire approximativement la texture dévelo^ppée au cours de la recristallisation après déformation à =70 %. Le caractère dispersé de la texture de recristallisation est difficile à obtenir. Le processus de maclage, actif au cours de la recristallisation, peut en être la cause, et doit être considéré par la suiteThe study of the relation between deformed inhomogeneities and static recrystallization is done in copper and -brass in cooper, a critic value of deformation (cold rolling to =90 %) is obtained from the bulk texture analysis. Below this value, the recrystallization texture {100}<001>is obtained. In x-brass, the deformation texture is even more complicated due to the deformation twinning mechanisms, which conducted to a weaker texture. The comparison of the experimental measurements in copper for two levels of reduction ( =70 % and =90 %) is done in order to understand the influence of the deformed state on recrystallization. Stored energy measurements show that minimum difference is needed between the C {112}<111>and/or S {123}<634>and the Cube orientations to produce the Cube texture. For both materials, a recovery of the Cube grains is observed. From EBSD measurements in copper =70 %, intergranular nucleation takes place in highly deformed regions, which conducts to a dispersed texture. In copper =90 %, this nucleation is not the main mechanism. Indeed, after recovery inside Cube/G {011}<100> transition bands, a fast process of nucleation and growth of the Cube orientation is observed. This corresponds to the oriented nucleation and growth hypothesis. In copper, Monte-Carlo simulation is used in order to explain the recrystallization texture after cold rolling to =70%. The experimental recrystallization texture is difficult to obtain, and this can be due to the annealing twinning active nucleation and growth steps
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Constantin, Joël. "Fracturation et paléocirculations de fluides dans les formations géologiques de faible perméabilité matricielle : le cas des argilités de Tournemire (Aveyron, France)." Paris 11, 2002. http://www.theses.fr/2002PA112017.
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Les formations géologiques argileuses présentent des propriétés potentiellement favorables pour le confinement des déchets radioactifs de haute activité et à vie longue (faible perméabilité et rétention des radioéléments). Mais ces propriétés peuvent être altérées par la présence de discontinuités dans le milieu. C'est pourquoi, la caractérisation des modalités de transferts de fluide associées à la fracturation s'est avérée nécessaire dans le cadre du programme de recherche Tournemire, lancé par l'Institut de Protection et de Sûreté Nucléaire (IPSN), dont l'objet d'étude est une épaisse série d'argilites d'âge Toarcien, localisée sur la commune de Tournemire (Aveyron, France). Dans un premier temps, la chronologie de la déformation du secteur de Tournemire a été mise en évidence par l'analyse microtectonique et microstructurale. Les principales étapes de la construction et de l'évolution du réseau de fractures affectant les argilites ont ainsi été reconstituées. L'analyse microstructurale des remplissages des fractures a révélé que celles ci ont été étanches, perméables ou encore semi-perméables au cours des différents événements tectoniques. On met en évidence que ces divers états hydrauliques sont fonction de la nature et de l'architecture des zones déformées en relation avec les modifications pétrophysiques des argilites, dans les zones centrales et les zones de dommage des fractures. Les mécanismes qui contrôlent les variations de perméabilité au sein des zones de fractures sont discutés et certains paramètres, comme les magnitudes de différentiel de contraintes, ont été estimés grâce à l'analyse des macles des cristaux de calcite contenus dans les zones centrales des fractures. L'analyse du maclage a apporté en outre des informations complémentaires concernant les contextes de déformation et le développement du réseau de fracturesDeep argillaceous formations have physical properties likely to favour the long-term radioactive waste disposal (very low intrinsic permeability, radioactive element retention). But, these properties may be changed by the existence of discontinuities in the host medium. It's why, the characterization of the processes of fluid migrations associated with the fracturing was necessary within the experimental research program, launched by the Institute for Nuclear Safety and Protection (IPSN), which study a thick Toarcian formation composed of claystones (argillites) located on the Tournemire area (Aveyron, France). In the first step, the microtectonic and kinematic analysis provided the chronology of deformation with the main steps of the setting and the evolution of the tectonic fractures network. The microstructural analysis of the filling fractures showed fractures was alternatively, during the tectonic events, tight, permeable or semipermeable (or semi-tight). These "hydraulic states" were controlled by the nature and architecture of the structures of deformation and by the petrophysics properties variations of the argillites in the core zone and damage zone of the fractures. Mechanisms involved in the permeability variations in the fractures were argued and some parameters, as the magnitudes of differential stress, were estimated by the dynamic analysis of the twinning of calcite crystals contained in the core zone of fractures. Besides, the twinning analysis provided several data about the contexts of deformation and the development of the fractures network in the argillites
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Liang, Liang. "Simulation ab initio des défauts étendus du Ti & en présence d'interstitiels H et O." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLX009/document.
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RÉSUMÉ : Le but de cette thèse est d’étudier en ab initio l’influence des solutés hydrogène ou oxygène sur les défauts étendus dans le titane alpha. Les résultats sont divisés en trois parties. Dans la première partie le site interstitiel octaédrique du Ti-alpha est trouvé être le site énergétiquement le plus favorable pour un H ou un O. Les calculs avec différentes concentrations en H ou O montrent que la présence d’H augmente le volume tandis que O a un effet inverse. La présence d’H en soluté diminue légèrement les constantes élastiques, la présence d’O a un effet opposé. Deux nouvelles SF sont trouvées dans la deuxième partie : une faute 0,57·(c+a) dans le plan π2 et 0,215·[1-102] dans le plan π1. La deuxième est reliée à la faible énergie de formation de la macle {10-11}. Un mécanisme de dissociation triple du cœur de la dislocation vis c+a est proposé. Mais cette dissociation ne semble pas se produire spontanément à partir d'un cœur de dislocation initialement parfait. Puisque la ségrégation à la faute signifie une diminution de l’énergie de faute, nous déduisons de nos calculs de ségrégation que la présence d'O rend sans doute la formation des SF énergétiquement plus difficile, contrairement au cas d’H. H ségrége fortement au cœur d’une dislocation vis a, avec une énergie variant de 0,06 à 0,30 eV, tandis que O y segrége très difficilement. Positionnés dans les sites les plus internes du cœur d’une dissociation prismatique métastable, en glissement, H et O induisent une dissociation dans le plan π1 ou vers une configuration prisme-π1 mélangée. Les barrières d'énergie de Peierls mesurées avec H et O dans différents sites et avec différentes concentrations montrent que H rend le glissement de la dislocation plus difficile, augmentant ainsi sans doute la cission critique résolue dans le plan prismatique, ce qui est en accord avec les mesures expérimentales. Mais les effets de H ne sont pas assez grands pour induire un glissement dévié vers le plan π1 et la dislocation continuera à glisser dans un même plan prismatique. Avec un O, la barrière d'énergie de Peierls est extrêmement élevée, beaucoup plus que celle pour un glissement dans le plan π1 ou un glissement dans le plan prismatique le plus proche. Du glissement dévié devrait ainsi être induit. Finalement, trois méthodes différentes de déformations de macles sont utilisées. Les stabilités structurale des joints de macles dépendent de leurs caractères structuraux intrinsèques mais aussi des modes de déformation appliqués. La macle la plus observée, {10-12}, et la macle {11-22} ne résistent pas à une déformation de plus de 1% ou 2% selon l’axe c. La présence de H ou O ségrégés améliorent la stabilité des macles {10-12} et {11-22}. Un modèle de dipôle de dislocations de mâclage (TD) est proposé pour permettre de simuler une TD dans une super-cellule de petite taille. Pour {10-12} et sa TD, les énergies de ségrégation de H et O mesurées au niveau du joint permettent de valider ce modèle. H et O peuvent se distribuer de manière plus ou moins homogène au joint et niveau de la TD mais pas dans les sites interstitiels de la couche atomique liée à la TDABSTRACT: The aim of this thesis is to study the influence of hydrogen or oxygen solutes on extended defects in alpha titanium by ab initio calculation. Results are divided into three parts. In a first part the octahedral interstitial site of alpha-Ti is found energetically more favorable for a H or an O atom. The presence of H increases the volume while O has the opposite effect. The presence of H slightly decreases the elastic constants of alpha-Ti while O has an opposite effect. In a second part two new SFs are found: 0.57·(c+a) on π2 and 0.215·[1-102] on π1 plane. The second one is related to the low formation energy of the {10-11} twin boundary. A c+a screw dislocation 3-part dissociation mechanism is proposed. However the c+a screw core tends to spread differently according to the initial core position and a complete 3-part dissociation is not found, which may mean that such a dissociation is not easily obtainable from an initially perfect dislocation core. As segregation to SF means a decrease of the SF energy, the presence of O may make the SF formation energetically more difficult, contrary to H case. H strongly segregates to the a screw dislocation core region with segregation energies varing from 0.06 to 0.3 eV while O hardly segregates to it. Both H and O in core sites change the meta-stable gliding prismatic dissociation to π1 plane or a prism-π1 plane mixed configuration. According to our measurements of Peierls energy barriers with H or O in different sites and concentrations, H makes the gliding more difficult, thus increasing the CRSS in prismatic plane, in agreement with experimental measurements. The effect of H is not big enough to induce a cross-slip of the gliding a-screw dislocation to the π1 plane and that screw will prefer to keep on gliding in its same prismatic plane. The Peierls energy barrier is extremely increased when an O is present in the core position, much higher than the barrier for π1 plane glide or a glide in the nearest prismatic plane. A cross-slip could happen in this case. In the last part, three different deformations are applied to TBs. Their structural stabilities depend not only on their intrinsic characters at the atomistic level but also on the deformation mode applied. {10-12}, {11-22} TB structures fail for deformations as low as 1% or 2% along the c-axis. The {11-21} and the {10-11} TBs are much more resistant. The presence of segregated H and O enhances the {10-12} and {11-22} TB limited stability. A twinning disconnection dipole model is proposed which allows the simulation of a TD in a size limited supercell. Segregation energy calculations with the {10-12} TB and its TD validate the model at the TB level and show that H and O should distribute more or less homogeneously to the TD core and the TB, with only a slight preference to the TD core although not at the interstitial sites of the atomic layer related to the disconnection step itself
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Ucer, Begum. "Design And Production Of Antireflection Coating For Ge, Znse And Zns In 8-12 Micrometer Wavelength Region." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12611308/index.pdf.
Full textAbstract:
This thesis describes the works done during the design and deposition process of the antireflection coating for the materials commonly used as refractive optical elements in thermal imaging systems. These coatings are quite necessary to reduce reflection losses from the surface of the optics and stray light that directly affects the image quality.
Germanium, zinc sulfide and zinc selenide were used as substrate material and their optical properties were investigated with infrared ellipsometry and FTIR. Antireflection coatings for each material operating in 8-12 μ
m range were designed with Needle Synthesis Technique. In order to shorten the optimization time, commercial software
&ldquo
The Essential Macleod&rdquo
was used. In order to reduce the reflectance losses multilayer structure was used in the coating design, and zinc selenide and lead telluride were used as low and high index materials. In this study the necessary theoretical background and common deposition techniques are reviewed. Samples were produced using the magnetron sputtering. To optimize the v thicknesses of the deposited layers, growth period and rate was controlled. Thicknesses of the samples, following to the deposition were also measured by thickness profilometer. A 3-layer coating, PbTe/ZnSe/PbTe, on ZnS and 2-layer coating PbTe/ZnS on Ge having more than 90% transmittance in 9.7-10.3 &
#956
m wavelength region have been successfully produced. Although, the measured range for 3 and 2- layer coating is narrower than the aimed one, it has been shown that, the method developed in this thesis would yield AR-coatings with broader spectral response if a system having better control on deposition parameters is used. For example, our design and optimization work has suggested that a 7-layer AR coating on germanium, with alternating high and low index layers is expected to give transmittance value greater than 93% in the studied wavelength region.
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Ferguson, Megan. "Patrick Geddes and the Celtic Renascence of the 1890s." Thesis, University of Dundee, 2011. https://discovery.dundee.ac.uk/en/studentTheses/7c9110f8-c0fc-4f2d-af9f-f66af1d6db7f.
Full textAbstract:
The fin de siècle was a time of change in nationalism, culture, art, science and religion. Nations and groups grew into defining themselves through movements such as Arts and Crafts and Art Nouveau. Some groups sought to define themselves through reviving aspects of their old cultures as inspiration. For instance, Finland found inspiration in the Kalavala and William Morris inspired Arts and Crafts through England’s Middle Ages. Scotland had many pasts to choose from for inspiration. Patrick Geddes found inspiration in its Celtic past. Geddes is best known for his work as a town planner and sociologist, but has been under-valued for his work as the leader of the 1890s cultural movement in Edinburgh, the Celtic Renascence. In an effort to revive the flagging Old Town, Geddes created a community in Ramsay Garden on the Castle Esplanade. Ramsay Garden became home to Summer Meetings, University Hall functions, and the Old Edinburgh School of Art, and out of all this emerged The Evergreen: A Northern Seasonal. The Evergreen served as a mouthpiece for the Celtic Renascence, a way for them to communicate the life of Ramsay Garden to those outside it. It was a journal which included art, literature and science, brought to the reader on a seasonal basis. Geddes’s view of Celticism was inclusive, he sought to include all peoples of Celtic nations (a view not all agreed with). But his Celtic Renascence was more than just a small art movement, it was part of his larger work to improve city life, to get people to broaden their perspectives and to generalise rather than specialise. Geddes used the Celtic Renascence, like any of his other projects, as a tool for positive and lasting change.
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Cheneau-Späth, Nadine. "Comportement de monocristaux et de polycristaux de métaux hexagonaux en grandes déformations plastiques : compression plane du titane et du magnésium." Grenoble INPG, 1996. http://www.theses.fr/1996INPG4201.
Full textAbstract:
La modélisation de l'évolution des textures de déformation des métaux hexagonaux, tels que le titane et le magnésium, et de l'anisotropie plastique des tôles manufacturées nécessitent la connaissance de leur comportement plastique lors des opérations classiques de mise en forme. Pour ce faire, nous caractérisons expérimentalement les mécanismes de déformation mis en jeu au cours de l'essai de compression plane sur plusieurs orientations de monocristaux de titane déformés à l'ambiante et de magnésium déformés à l'ambiante et à 400°C, en conditions de glissement et de maclage multiple, que nous comparons aux simulations numériques de type Taylor-Bishop et Hill généralisées. Ainsi, ce travail se distingue par la réalisation de monocristaux de titane de grandes dimensions, obtenus par cyclage en température autour du transus α↔β. Il a également donné lieu à la mise au point d'une nouvelle technique de détermination précise et univoque des systèmes de maclage par microdiffraction EBSD et analyse des traces associées. Les résultats de nos expériences nous donnent les valeurs suivantes des rapports de cissions critiques résolues sur les différents systèmes: Pour le magnésium, en prenant la cission critique résolue pour le glissement basal égale à 1 : 20 pour les glissements prismatique et pyramidal, 3 pour le maclage {1 0 -1 2} et 10 pour les maclages {1 0 -1 1} et {1 0 -1 3}. Pour le titane, la valeur de référence étant la cission critique résolue pour le glissement prismatique: 5 pour le glissement basal, 4 pour le glissement pyramidal →a, pour le glissement pyramidal →c+→a 2 en traction et 3 en compression, 1,5 pour les maclages {1 0 -1 2} et {1 1 -2 1} et 5 pour le maclage {1 1 -2 2}. Nous avons ainsi pu corréler l'évolution des textures de déformation obtenues au comportement individuel des grains de l'agrégat polycristallin.
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Ragaru, Christian. "Étude par microscopie électronique en transmission de la transformation de phase bêta-SiC, >alpha-SiC par maclage." Nantes, 1997. http://www.theses.fr/1997NANT2118.
Full textAbstract:
Le carbure de silicium est un covalent binaire qui possède une forte aptitude au polytypisme. Lors du frittage de nos échantillons, au dessus de 2000c, la transformation de phase beta (cubique-diamant) alpha-sic (polytypes hexagonaux et rhomboédriques), aboutit à la croissance massive de bicristaux de grandes dimensions en forme de fer-de-lance ou de plume. Ces plumes possèdent un axe commun 11-20, et un angle diedral atypique de 65,5, 64 ou 41,4 entre les plans denses (0001). Nous discutons la nucléation et la croissance de ces plumes en nous appuyant sur les caractéristiques microstructurales des phases alpha et beta. Nous avons donc caractérisé des joints de grains et des défauts par methr afin d'expliquer la formation d'un tel bicristal. L'analyse montre que les joints et défauts peuvent s'interpréter en terme d'unités structurales proches de celles des covalents simples (si, ge). Cependant, le caractère ionique et binaire de sic permet d'accommoder des déformations de manière plus variée que pour le silicium. L'étude des plumes montre que la régularité et l'originalité de leurs angles diedraux ne peut s'expliquer par une minimisation des distorsions du joint et donc de l'énergie du matériau. Nous nous sommes bases sur un modèle de transformation de phase par double-glissement dévié de dislocations propose par Pirouz. Ce mécanisme, initialement développé pour le silicium, permet de décrire la formation des plaquettes dans sic. En émettant des hypothèses basées sur la microstructure des phases alpha et beta, nous avons adapté ce modèle et montre qu'il peut rendre compte de la nucléation des plumes. Nous avons ensuite discuté le mécanisme de croissance des plumes.
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Noreikaitė, Kristina. "Finansų maklerio įmonės veiklos automatizavimo sistemos prototipas." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2005. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2005~D_20050110_205101-95519.
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