This thesis is a study of the morphology and sediment transport dynamics of mountain streams in southeast Australia. Mountain streams represent important geomorphological and ecological systems in Australia which have hitherto been poorly studied. The variability of mountain stream reach morphology was investigated at the regional scale using topographical surveys and sediment sampling techniques. Study sites were stratified by slope and local lithology. Eight channel-morphologies including Bedrock, Cascade, Step-pool, Planebed, Pool-Riffle, Cascade-pool, Riffle-step and Infilled, were identified using an objective statistical approach. Overall, channel types were found to correspond to existing reach-scale mountain stream templates. Five morphologies were associated with a specific lithology type which controlled the size and shape of grains supplied to the channels. Differences in coarse sediment transport processes between morphologies were investigated using stream monitoring techniques and Optically Stimulated Luminescence (OSL) dating. Monitoring results from a 3 year period indicated that channel beds are resistant to entrainment with shear stress thresholds for bedload transport ranging between 64 to 74 N/m2. Transport of reach median grain sizes requires floods that exceed bankfull discharge. Existing competence equations were found to over-predict the hydraulic driving force and consequently, a modified entrainment model was used to account for the regional channel characteristics. OSL dating was investigated as a tool to provide data on long-term sediment transport processes. Minimum age model results from the OSL dates show overall agreement with a selected entrainment model, and indicate differences in sediment transport dynamics between some reach morphology types. A regime model was used to quantify the physical domains of different channel morphologies. Limitations of the model were overcome by modifying the sediment supply surrogate to better reflect the dominant transported bedload size. Morphology types were delineated according to different sediment transport capacity-sediment supply domains. The distribution of channel morphology types within a series of catchments in southeast Australia was modelled within a GIS platform using the diagnostics of reach morphology derived from this study. The model provides a conceptual framework to evaluate the potential link between channel form, potential habitat diversity and aquatic biodiversity within the channel network in mountain streams.

This thesis is a study of the morphology and sediment transport dynamics of mountain streams in southeast Australia. Mountain streams represent important geomorphological and ecological systems in Australia which have hitherto been poorly studied. The variability of mountain stream reach morphology was investigated at the regional scale using topographical surveys and sediment sampling techniques. Study sites were stratified by slope and local lithology. Eight channel-morphologies including Bedrock, Cascade, Step-pool, Planebed, Pool-Riffle, Cascade-pool, Riffle-step and Infilled, were identified using an objective statistical approach. Overall, channel types were found to correspond to existing reach-scale mountain stream templates. Five morphologies were associated with a specific lithology type which controlled the size and shape of grains supplied to the channels. Differences in coarse sediment transport processes between morphologies were investigated using stream monitoring techniques and Optically Stimulated Luminescence (OSL) dating. Monitoring results from a 3 year period indicated that channel beds are resistant to entrainment with shear stress thresholds for bedload transport ranging between 64 to 74 N/m2. Transport of reach median grain sizes requires floods that exceed bankfull discharge. Existing competence equations were found to over-predict the hydraulic driving force and consequently, a modified entrainment model was used to account for the regional channel characteristics. OSL dating was investigated as a tool to provide data on long-term sediment transport processes. Minimum age model results from the OSL dates show overall agreement with a selected entrainment model, and indicate differences in sediment transport dynamics between some reach morphology types. A regime model was used to quantify the physical domains of different channel morphologies. Limitations of the model were overcome by modifying the sediment supply surrogate to better reflect the dominant transported bedload size. Morphology types were delineated according to different sediment transport capacity-sediment supply domains. The distribution of channel morphology types within a series of catchments in southeast Australia was modelled within a GIS platform using the diagnostics of reach morphology derived from this study. The model provides a conceptual framework to evaluate the potential link between channel form, potential habitat diversity and aquatic biodiversity within the channel network in mountain streams.

This thesis is a study of the morphology and sediment transport dynamics of mountain streams in southeast Australia. Mountain streams represent important geomorphological and ecological systems in Australia which have hitherto been poorly studied. The variability of mountain stream reach morphology was investigated at the regional scale using topographical surveys and sediment sampling techniques. Study sites were stratified by slope and local lithology. Eight channel-morphologies including Bedrock, Cascade, Step-pool, Planebed, Pool-Riffle, Cascade-pool, Riffle-step and Infilled, were identified using an objective statistical approach. Overall, channel types were found to correspond to existing reach-scale mountain stream templates. Five morphologies were associated with a specific lithology type which controlled the size and shape of grains supplied to the channels. Differences in coarse sediment transport processes between morphologies were investigated using stream monitoring techniques and Optically Stimulated Luminescence (OSL) dating. Monitoring results from a 3 year period indicated that channel beds are resistant to entrainment with shear stress thresholds for bedload transport ranging between 64 to 74 N/m2. Transport of reach median grain sizes requires floods that exceed bankfull discharge. Existing competence equations were found to over-predict the hydraulic driving force and consequently, a modified entrainment model was used to account for the regional channel characteristics. OSL dating was investigated as a tool to provide data on long-term sediment transport processes. Minimum age model results from the OSL dates show overall agreement with a selected entrainment model, and indicate differences in sediment transport dynamics between some reach morphology types. A regime model was used to quantify the physical domains of different channel morphologies. Limitations of the model were overcome by modifying the sediment supply surrogate to better reflect the dominant transported bedload size. Morphology types were delineated according to different sediment transport capacity-sediment supply domains. The distribution of channel morphology types within a series of catchments in southeast Australia was modelled within a GIS platform using the diagnostics of reach morphology derived from this study. The model provides a conceptual framework to evaluate the potential link between channel form, potential habitat diversity and aquatic biodiversity within the channel network in mountain streams.

This thesis is a study of the morphology and sediment transport dynamics of mountain streams in southeast Australia. Mountain streams represent important geomorphological and ecological systems in Australia which have hitherto been poorly studied. The variability of mountain stream reach morphology was investigated at the regional scale using topographical surveys and sediment sampling techniques. Study sites were stratified by slope and local lithology. Eight channel-morphologies including Bedrock, Cascade, Step-pool, Planebed, Pool-Riffle, Cascade-pool, Riffle-step and Infilled, were identified using an objective statistical approach. Overall, channel types were found to correspond to existing reach-scale mountain stream templates. Five morphologies were associated with a specific lithology type which controlled the size and shape of grains supplied to the channels. Differences in coarse sediment transport processes between morphologies were investigated using stream monitoring techniques and Optically Stimulated Luminescence (OSL) dating. Monitoring results from a 3 year period indicated that channel beds are resistant to entrainment with shear stress thresholds for bedload transport ranging between 64 to 74 N/m2. Transport of reach median grain sizes requires floods that exceed bankfull discharge. Existing competence equations were found to over-predict the hydraulic driving force and consequently, a modified entrainment model was used to account for the regional channel characteristics. OSL dating was investigated as a tool to provide data on long-term sediment transport processes. Minimum age model results from the OSL dates show overall agreement with a selected entrainment model, and indicate differences in sediment transport dynamics between some reach morphology types. A regime model was used to quantify the physical domains of different channel morphologies. Limitations of the model were overcome by modifying the sediment supply surrogate to better reflect the dominant transported bedload size. Morphology types were delineated according to different sediment transport capacity-sediment supply domains. The distribution of channel morphology types within a series of catchments in southeast Australia was modelled within a GIS platform using the diagnostics of reach morphology derived from this study. The model provides a conceptual framework to evaluate the potential link between channel form, potential habitat diversity and aquatic biodiversity within the channel network in mountain streams.

La datation directe de l’édification de maçonneries est l’objectif archéologique majeur de cette thèse qui s'inscrit dans un contexte interdisciplinaire. Il s’agit de mettre au point une méthode de datation des mortiers, matériaux de choix beaucoup plus représentatifs de la chronologie de l’édification que les briques ou les bois de charpentes qui peuvent être remployés. Les mortiers de chaux, constitués d'un mélange de chaux et de sable, peuvent être datés par luminescence optiquement stimulée : il s’agit en effet de remonter à la fin de la dernière exposition à la lumière des grains de sable qui ont été ajoutés à la chaux par les anciens bâtisseurs, ce qui correspond précisément à la fabrication du mortier au moment de l’édification. Les monuments datés dans ce travail forment un ensemble d’édifices de référence s'étendant de l'Antiquité gallo-romaine jusqu'à la fin du Moyen Âge, bien calés chronologiquement par les approches chronologiques indépendantes. L’objectif est de comparer la chronologie obtenue par OSL à celle connue et démontrer ainsi la validité de la méthode. La procédure de datation des mortiers par OSL est compliquée par plusieurs facteurs. D’abord, le blanchiment optique des grains de quartz du mortier n’est pas uniforme en raison de l’éventuelle faible durée d’exposition à la lumière. En plus, une faible ancienneté des objets à dater (2000 ans au maximum) implique des signaux de faible amplitude et la nécessité d’adapter le protocole de mesure. Enfin, particulièrement les mortiers grossiers peuvent être affectés par les effets microdosimétriques. Ces facteurs sont pris en compte dans le choix de méthodologie de datation qui comprend ainsi les étapes suivantes : la caractérisation du mortier par microscopie optique, par EDX-MEB et par imagerie beta, la mesure des doses archéologiques individuelles par la technique de monograin, la détermination de la dose annuelle et le calcul de la dose archéologique ou bien de l’âge. Cette dernière est une étape délicate car il s’agit de sélectionner dans les distributions des doses archéologiques individuelles les grains bien blanchis qui portent une information chronologique recherchée. Pour cela, les différentes approches statistiques habituellement utilisées en datation par luminescence sont testées. Cette thèse apporte une démonstration de la méthode et montre que dans de nombreux cas, elle peut produire des dates fiables. L’analyse individuelle de chaque grain est ici un seul moyen permettant d’obtenir des informations exactes sur la vraie nature du matériau étudié. / The heart of the proposed research lies in the possibilities of direct dating of historical constructions, the interdisciplinary issues of a high significance. The aim of this research is to put into practice a dating method dealing with mortars, the category of materials more convenient and much more representative for the chronology of buildings in comparison with bricks or wood constructions that may be reused. Lime mortars composed of the mixture of sand and lime can be dated by optically stimulated luminescence: the objective is to determine the last moment when the grains of sand have been exposed to light which corresponds exactly with the fabrication of the mortar at the moment of building. The monuments dated within this PhD. thesis constitute a group of reference structures from the Gallo-Roman antiquity to the Middle Ages well-dated by other independent chronological approaches. The objective is to compare the chronology obtained by OSL with the known one and thereby to proof the validity of the method. The OSL dating procedure of mortars is complicated by numerous factors. First of all, due to the short exposure to light the optical bleaching of quartz grains in mortar is not homogeneous. In addition, the young age of dated material (maximally 2000 years old) implies signals of a weak intensity and the necessity to adapt conveniently the measurement protocol. Finally, especially the coarse-grained mortars can be affected by the microdosimetric effects. All these factors are taken into account when selecting a convenient dating methodology comprising the following stages: characterization of mortar by optical microscopy, by SEM-EDX and by beta autoradiography, the measurement of individual archaeological doses by the single grain technique, the determination of the annual dose and the calculation of the archaeological dose and of the age. The latter stage is a tricky one; it is necessary to select from the measured distribution of archaeological doses the well-bleached grains that contain the right chronological information. In this context, different statistical approaches usually used in luminescence dating are tested. This thesis brings a demonstration of the OSL dating method and shows that in many cases we can get reliable dates. The individual analysis of each grain is here the only way how to get the precise information about the nature of the studied material.

In Medizin und Technik besteht ein Bedarf an flexiblen, miniaturisierten Dosisleistungs-messgeräten mit hoher Ortsauflösung für den Einsatz in Strahlungsfeldern hoher Dosisleistung und Dosisleistungsgradienten. Lichtwellenleiterbasierte Dosisleistungsmess-systeme können diese Anforderungen erfüllen. Sie bestehen aus einem strahlungssensitiven Leuchtstoff, welcher über einen flexiblen Lichtleiter an einen Lichtdetektor gekoppelt ist. Die Eliminierung des dominierenden Störeinflusses, des bei Bestrahlung des Lichtleiters generierten Stem-Effekts, ist eine inhärente Herausforderung aller lichtwellenleiter¬basierten Dosisleistungsmesssysteme. In der vorliegenden Arbeit wird ein solches System unter Verwendung der Lumineszenz der gewebeäquivalenten Detektormaterialien Berylliumoxid und Lithiumtetraborat realisiert. Der Schwerpunkt liegt dabei auf der Untersuchung von Methoden der Stem-Eliminierung unter Nutzung der zeitlichen Charakteristik der Lumineszenzmaterialien sowie der zeitlichen Struktur des Strahlungsfeldes oder einer modulierten optischen Stimulation. Eine performante Ausleseelektronik auf FPGA-Basis ermöglicht Echtzeit-Messungen mit einer Abtastung von 10 ns. Verschiedene Auswertemethoden generieren aus den Rohdaten in Zeitstempelform eine stem-unabhängige, dosisleistungsproportionale Detektorantwort. / In medicine and technology there is a demand for flexible, miniaturized dose rate measurement systems with high spatial resolution for the application in radiation fields of high dose rates and dose rate gradients. Fiber optic coupled dosimeters can meet these requirements. They consist of a radiation sensitive luminescent material which is connected to a light detector with a flexible light guide. The elimination of the dominant perturbation, which is the stem effect generated by irradiation of the light guide, is one inherent challenge of all fiber optic dosimeters. In the present work such a system is realized, using the luminescence of the two tissue equivalent detector materials beryllium oxide and lithium tetraborate. The main focus is on the investigation of methods of stem elimination, exploiting the temporal characteristics of the luminescent materials, as well as the time structure of the irradiation or a modulated optical stimulation. For this purpose, capable FPGA-based read out electronics are employed, which enable real time measurements with 10 ns sampling. Different methods of analysis process the time stamp raw data and generate a stem-free, dose rate proportional detector response.

No description available.

Cette thèse a pour objectif d’établir une vision globale et continue mer-terre-mer d’une barrière littorale paraglaciaire, en combinant une approche morphologique et architecturale. L’originalité de l’isthme de Miquelon-Langlade (NO Atlantique) entre les deux îles éponymes réside en sa diversité et complexité de systèmes (flèches, cordons littoraux, lagune) qui s’emboitent formant une barrière composite évoluant le long de deux façades ouvertes sur l’océan. Ce travail a été rendu possible grâce à l’association de données topographiques (GPS-RTK), de géophysique marine (sismique HR) et terrestre (géo-radar), sédimentaires (carottes, échantillons de surface) ainsi que des datations par OSL. L’étude de cette barrière a permis 1) d’identifier l’ensemble des dépôts d’une séquence paraglaciaire (dépôts de chute, bas niveau, augmentation et haut niveau marin); 2) de pointer l’importance de la géométrie des îles, du substratum rocheux ainsi que de la topographie héritée dans la formation de la barrière; 3) de définir l’architecture interne de beach ridges mixte sable-galet; et 4) de pointer le potentiel de ces systèmes en tant marqueur du paléo-niveau marin tout en proposant la première courbe de tendance de l’évolution du RSL pour l’Archipel de Saint-Pierre-et-Miquelon sur les derniers 3000 ans (+1mm/an). L’association de l’ensemble de ces informations a permis de proposer un schéma de mise en place de la barrière, depuis le retrait de la calotte (13 700 ans) jusqu’à sa forme actuelle, évoluant dans un contexte d’augmentation du RSL et de fort apport sédimentaire, tout en proposant une vision de détail de la formation de la plaine de beach ridges au cours des derniers 3000 ans. / The purpose of this PhD thesis was to define a complete and continuous sea-land-sea view of a paraglacial coastal barrier system, combining morphological and architectural approaches. Particularity of the Miquelon-Langlade isthmus (NO Atlantic) lies in its diversity and complexity of systems (spits, beach ridges, and lagoon) that fit together to form a composite barrier prograding along two open coasts. Investigations of this barrier included topographic (RTK-GPS), ground-penetrating radar (GPR) seismic, sedimentary (cores, augers, samples) and chronologic (OSL) data collections. This study of this paraglacial composite barrier make possible 1) to characterize all deposits of the paraglacial sequence (FSST, LST, TST, HST); 2) to emphasize the primary influence of islands geometry, bedrock and inherited topography on the coastal progradational pattern; 3) to provide a better understanding of the internal architecture of depositional processes and driving mechanisms of mixed sand-and-gravel beach ridges; 4) to examine the potential of these mixed beach-ridge systems to record and preserve paleo-sea-level information, to produce the first sea level trends for the Saint-Pierre-et-Miquelon archipelago over the last 3000 years. The combination of all these data provide a model of development of the barrier since the ice sheet retreat (13 700 yrs) to its present form, in a context of RSL rise and high local glaciogenic sediment supply, and a detailed view of the formation of the beach ridge plain over the last 3000 yrs.

Объекты разработки и исследования: канал лазерной стимуляции для измерения электрофизических параметров структуры Ti/TiO2-НТ/Au и канал оптической стимуляции для исследования люминесцентных свойств нанопорошка гексагонального нитрида бора. Цель работы – разработать измерительные каналы лазерной стимуляции исследуемых образцов на основе контроля и управления параметрами излучения в различных режимах в ходе экспериментальных исследований оптически стимулированных и родственных процессов в широкозонных наноструктурированных материалах. В результате работы разработан канал лазерной стимуляции для существующего комплекса по измерению вольт-амперных характеристик на базе микрозондовой станции Cascade Microtech MPS 150, а также модернизирован канал оптической стимуляции на базе люминесцентного спектрометра Perkin Elmer LS 55 со встроенной высокотемпературной приставкой. Реализованные программно-аппаратные измерительные комплексы позволили успешно применить на практике методики исследования широкозонных наноструктур посредством оптически стимулированных процессов. Полученные в ходе работы данные, как для образцов Ti/TiO2-НТ/Au, так и для наноструктурированного порошка h-BN, отлично согласуются с результатами различных исследовательских работ из независимых научных источников. / Objects of development and research: a laser stimulation channel for measuring the electrophysical parameters of the Ti/TiO2-HT/Au structure and an optical stimulation channel for studying the luminescent properties of a hexagonal boron nitride nanopowder. The aim of the work is to develop measuring channels of laser stimulation of the studied samples based on the control and operating of radiation parameters in various modes during experimental studies of optically stimulated and related processes in wide-gap nanostructured materials. As a result of the work, a laser stimulation channel was developed for the existing complex for measuring current-voltage characteristics based on the Cascade Microtech MPS 150 microprobe station, and the optical stimulation channel was modernized on the basis of a Perkin Elmer LS 55 luminescence spectrometer with a built-in high-temperature attachment. The implemented software and hardware measuring systems made it possible to successfully apply in practice the methods of studying wide-gap nanostructures by means of optically stimulated processes. The data obtained during the work, both for the Ti / TiO2-NT / Au samples and for the nanostructured h-BN powder, are in excellent agreement with the results of various research works from independent scientific sources.