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Zhou, Yu. "Investigating past and present continental earthquakes with high-resolution optical imagery." Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:2792e6e7-b1f9-4bd3-ad40-3dc96e113251.
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Over the past few decades, remote sensing has emerged as a powerful tool for studying active faulting in continental regions. However, the commonly used remote sensing techniques, including radar interferometry, visual inspection of imagery, and image matching, cannot measure three-dimensional (3D) surface displacements in earthquakes, limiting our ability to investigate faulting. The improvement of very high-resolution (VHR) optical imaging systems (stereo in particular) in recent years has made it possible for earth scientists to measure 3D surface deformation remotely. In this thesis, I contribute to assessing the capability of VHR optical imagery, by determining earthquake deformation from four different types of earthquakes (different in sense of slip and date of the event). In the case of the 2010 Mw 7.2 El Mayor-Cucapah, Mexico earthquake, I show that digital elevation models (DEMs) derived from Pleiades stereo imagery are comparable to light detection and ranging (LiDAR) surveys, and differencing pre- and post-earthquake DEMs can measure 3D displacements, which will be very useful for studying future earthquakes. For the 2013 Mw 7.7 Balochistan, Pakistan earthquake, I determine the vertical motion from a post-earthquake Pleiades DEM and find constant fault kinematics throughout the Late Quaternary. This study has resolved a current controversy of the Balochistan earthquake, in which it has been argued that kinematics of the Hoshab fault switches between strike-slip and dip-slip. Applying historical aerial, KH-9 Hexagon spy satellite, SPOT-2 and modern SPOT-6 images to the 1978 Mw 7.3 Tabas-e-Golshan earthquake, I measure the coseismic and postseismic displacements, and show that the Tabas fold system in eastern Iran may exhibit characteristic slip behaviour. Combining Pleiades imagery, fieldwork and geological dating techniques, I determine slip in the 1556 Huaxian earthquake in China and the recurrence interval for similar events. These examples demonstrate the usefulness of high-resolution optical imagery in investigating past and present earthquakes.
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Shrestha, Alen. "ANALYZING THE PAST AND FUTURE DROUGHT SITUATIONS USING HIGH RESOLUTION DROUGHT INDEX." OpenSIUC, 2020. https://opensiuc.lib.siu.edu/theses/2757.
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Regional assessments of droughts are limited and meticulous assessment of droughts over larger spatial scales are often not substantial. Understanding drought variability on a regional scale is crucial for enhancing resiliency and adaptive ability of water supply and distribution systems. Moreover, it can be essential for appraising the dynamics and predictability of droughts based on regional climate across various spatial and temporal scales. The drought analysis of the past was carried out with the development of a high-resolution dataset (1km×1km) for three drought-prone regions of India between 1950 and 2016. In the study the monthly values of self-calibrating Palmer Drought Severity Index (scPDSI), incorporating Penman–Monteith (PM) approximation, which is physically based on potential evapotranspiration. Climate data were statistically downscaled using the delta downscaling method and was formulated to form a timeline for characterizing major drought events that occurred in the past. The downscaled climate data were validated with the station observations. Major severe drought events that occurred between 1950 and 2016 were identified and studied with greater emphasis to the drought situation in smaller spatial extent such as districts, villages or localities. A timeline of drought events within the period of study was also prepared to have an understanding of the severity of drought in all three regions.Likewise, the future drought durations are projected for droughts of different levels of severity and assessed in the same regions of India. Coupled Model Intercomparison Project Phase 6 (CMIP6) simulated precipitation and climate data were used for near‐future (2015–2044) for different shared socio-economic pathways (SSPs). scPDSI, was used again based on its fairness in identifying drought conditions which accounts for the temperature as well. Gridded rainfall and temperature data of spatial resolution of 1km were used to bias correct the multi-model ensemble (MME) mean of 7 Global Climatic Models (GCMs) from CMIP6 project. Equidistant quantile-based mapping was adopted to remove the bias in the rainfall and temperature data and were corrected at the monthly scale. The downscaled climate data exhibited good statistical agreement with station data with correlation coefficient (R) ranging from 0.83 to 0.93 for both precipitation and temperature. Drought analysis indicated several major incidences over the analysis time period considered in this work, which truly adheres to the droughts recorded in qualitative reports of meteorological institutions in those regions. The drought study of the past helped to understand the situation in local levels and understand the necessities that can be opted for the future by proper management of water resources. While the outcome of the future prediction of drought duration suggests multiple severe to extreme drought events in all three study areas of appreciable durations mostly during the mid-2030s under the SSP2-4.5 scenario. The severe drought durations under the SSP2-4.5 scenario were found to be ranging around 25 to 30 months in 30 years period of the near future. The high-resolution drought index proved to be key to assess the drought situation for both the past and the future in three different drought-prone regions of India.
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Wallace, Elizabeth Jane. "High resolution sedimentary archives of past millennium hurricane activity in the Bahama Archipelago." Thesis, Massachusetts Institute of Technology, 2020. https://hdl.handle.net/1721.1/129063.
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Thesis: Ph. D., Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution), 2020Cataloged from student-submitted PDF of thesis.
Includes bibliographical references (pages 211-226).
Atlantic hurricanes threaten growing coastal populations along the U.S. coastline and in the Caribbean islands. Unfortunately, little is known about the forces that alter hurricane activity on multi-decadal to centennial timescales. This thesis uses proxy development and proxy-model integration to constrain the spatiotemporal variability in hurricane activity in the Bahama Archipelago over the past millennium. I present annually-resolved archives of storm activity stretching over the past 1000 to 1500 years in sediment cores from blue holes on three islands in the Bahama Archipelago: South Andros Island, Long Island, and Middle Caicos Island. I explore the sensitivity of each site to coarse-grained sediment deposition for modern storms. I find that the local geomorphologic conditions and the angle of approach and size of passing storms play a more important role in inducing coarse-grained sediment transport than storm intensity.
All three paleorecords capture multi-decadal and longer periods of elevated hurricane activity over the past millennium. Dramatic differences between these records suggest localized controls on the hurricane patterns observed by each island. Thus, compiling the records from this thesis together more accurately captures regional variations in hurricane strikes. Integrating our new Bahama Archipelago compilation with compiled paleohurricane records from the U.S. coastline indicates shifting patterns of hurricane activity over the past millennium between the Gulf Coast and the Bahama Archipelago/New England. I attribute these shifting storm patterns to changes in local environmental conditions and/or large-scale variations in hurricane tracks. Finally, I address whether variability in hurricane strikes observed in Bahamian paleohurricane records is related to climate or random variability.
Using a large suite of synthetic storms run over past millennium climate, I generate 1000 pseudo paleohurricane records containing centennial-scale signal like our proxy reconstructions. However, the signal observed in any individual record of paleohurricane activity from the Bahama Archipelago is driven more by random variability in hurricane tracks than by climate. This thesis lays the groundwork for creating high-resolution paleohurricane records from coastal karst basins and using hurricane models to inform our interpretations of these records.
by Elizabeth Jane Wallace.
Ph. D.
Ph.D. Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution)
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Kowaka, Yasuyuki. "Structure and excited-state dynamics of PAHs : High-resolution spectroscopy and theoretical calculation." 京都大学 (Kyoto University), 2012. http://hdl.handle.net/2433/157801.
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Ariel, Robert. "The Contribution of Past Test Performance, New Learning, and Forgetting to Judgment-of-Learning Resolution." Kent State University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=kent1277315741.
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Fakhoury, Hussein. "Conception de modulateurs Delta-Sigma passe-bas en technologie CMOS pour des applications à large bande passante et haute résolution." Thesis, Paris, ENST, 2014. http://www.theses.fr/2014ENST0088/document.
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Le marché des convertisseurs analogique-numérique peut être segmenté en deux catégories de circuits. Nous distinguons d’une part, les blocs de propriété intellectuelle (IP) qui sont généralement optimisés pour une application spécifique. Et d’autre part, les circuits intégrés discrets qui sont conçus pour répondre aux besoins d’une plus large gamme d’applications. Ce travail de thèse concerne la deuxième catégorie de composants. Il s’inscrit dans le cadre d'un programme de recherche et développement initié en 2010 dans le projet européen FP7 SACRA et dont le but était d'étudier la faisabilité d'un convertisseur analogique-numérique Delta-Sigma (DS) qui pourrait rivaliser avec l'architecture pipeline pour des applications nécessitant une large bande passante (≥10MHz) et une haute résolution (>10-bit) comme l’imagerie médicale, les communications numériques sans fils ou câblées, la vidéo ou encore l’instrumentation. Ce manuscrit synthétise les travaux de conception, fabrication et mesure d’un modulateur DS Passe-bas à temps continu avec une bande passante de 40MHz, et visant une résolution effective de 12-bit tout en consommant moins de 100mWThe market of A/D converters can be segmented in two categories. From one side we distinguish the Intellectual Property (IP) blocks that are generally optimized for a specific application. On the other side, the general-purpose discrete Integrated Circuits (ICs) that are designed such as they could be used in different applications. This thesis work deals with the second category. It is part of a research and development program initiated in 2010 in the European project FP7 SACRA, whose purpose was to study the feasibility of a delta-sigma (DS) analog-to-digital converter that could compete with the pipeline architecture for applications that require high bandwidth (≥10MHz) and high resolution (>10-bit) such as medical imaging, wireless and wireline communications, video or instrumentation. Currently, the pipeline is still largely predominant for such applications and the few commercial wideband solutions based on a DS architecture have a signal bandwidth limited to 10 MHz or 25 MHz while consuming respectively 100mW and 20mW for an ENOB around 12-bit. This manuscript summarizes the design, fabrication and measurement of a low-pass CT DS modulator with a signal bandwidth of 40MHz, while targeting an effective resolution of 12-bit and a power consumption of less than 100mW
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Snook, Daniel Walter II. "Is What Is Past Always Prologue? Priming to Past Conflicts and Fear of Terrorism Influence Americans’ Support for Military Intervention in Syria." UNF Digital Commons, 2015. http://digitalcommons.unf.edu/etd/561.
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Implicit knowledge influences decision-making in a variety of areas, including conflict resolution and decisions about war. Individuals may unknowingly apply implicit knowledge from past experiences to present experiences, even if that information leads to less accurate decisions in the present experience. The current study is an exploration into how implicit knowledge of past international conflicts and fear of terrorism affects recommendations for military conflict resolution in current international conflicts. Priming is one way to make implicit knowledge salient, and participants in this study were implicitly primed to think of either the Iraq War, World War II, or no war in particular before reading a description of the Syrian Civil War. Participants reported their recommendations for resolving the conflict in Syria, including to what extent they would recommend that the United States intervene using military force. Fear of Terrorism, which is theoretically linked to knowledge and attitudes about Middle Eastern conflicts, was also measured. Results showed that support for U.S. military intervention in Syria was significantly impacted by Fear of Terrorism when participants had been primed to think of the Iraq War. This effect was such that, when primed to think of the Iraq War, higher Fear of Terrorism predicted greater support for military intervention in Syria. This effect did not occur in the other priming conditions. This study extends current research by examining how implicit priming of past conflicts and fear of terrorism interact to influence Americans’ decision-making in support for military intervention in Middle Eastern conflicts.
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Olukotun, Deji. "The spirit of National Peace Accord : the past, present and future of local forms of conflict resolution in the Western Cape." Master's thesis, University of Cape Town, 2006. http://hdl.handle.net/11427/3708.
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Becerra, Patricio, and Patricio Becerra. "The Poles of Mars, Past and Present: A High-Resolution Observational Study of the Martian Polar Regions and their Connection to Climate." Diss., The University of Arizona, 2016. http://hdl.handle.net/10150/621066.
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The poles of Mars, much like Earth's polar regions, are covered by kilometer-thick sheets of ice that interact with the Martian atmosphere and can record climatic changes in their stratigraphy. These polar caps are composed of several icy sections that interact with the Martian environment over different timescales. This dissertation describes my investigation of two of these units: The South Polar Residual Cap (SPRC), and the North Polar Layered Deposits (NPLD). The overarching theme of my work is to explore the connections between these caps and the current (SPRC) and past (NPLD) climate of Mars using a wide variety of data from spacecraft missions, and applying numerical models of surface properties and processes to interpret the observations. The SPRC is a ~10 meter thick slab of bright carbon dioxide ice that is covered by pits and scarps formed by differential sublimation. It is unclear whether this cap is in a state of net accumulation or net ablation. During the summer of Mars Year 28 (2006/2007), The High Resolution Imaging Science Experiment (HiRISE) observed an apparent increase in brightness near the edges of these pits that had not been seen before, and was not seen in the few years following. I analyzed hundreds of images from HiRISE and the Mars Orbiter Camera (MOC), as well as data from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) to search for compositional and/or grain-size changes in the ice that could explain these "halos". I coupled my observations with numerical modeling of the spectral reflectance of the ice, to explore the effects of different ice grain sizes and minuscule dust inclusions on the observed brightness. I concluded that the features were caused by the occurrence of a global dust storm, after which the depositing dust actually acted to darken the SPRC. The halos were thus areas that had been kept relatively "clean" of the depositing dust, thanks to winds driven by enhanced sublimation from the pit walls. The fact that the halos did not show up in subsequent years means that they had not been exhumed, and that flat areas of the SPRC are in a state of net accumulation. It is likely that events like these result in new flat surfaces formed by snowfall driven by the depositing dust, which could explain the persistence of the cap throughout history. The polar layered deposits (PLD) are kilometer-thick stratified dome structures composed of dusty water ice that make up the bulk of the polar caps. The layers that make up the PLD are thought to record climatic variations over timescales of millions of years, in a similar way to Earth's ice caps. These caps are dissected by deep troughs that allow us to observe outcrops of their internal layers and map the stratigraphy. In the past, researchers have done this using layer brightness. However, remotely observed brightness has been shown to be affected by many external factors and may not represent an intrinsic property of the layers. Using Digital Terrain Models (DTM) made from HiRISE stereo images of NPLD outcrops, I mapped the change with depth of each layer's topographic protrusion from the scarp slope, defining the stratigraphy with a property related to the layers' resistance to erosion. I mapped the protrusion stratigraphy of 16 sites throughout the NPLD, and correlated the stratigraphic profiles from a subset of these sites, with Context Camera (CTX) images and signal-matching algorithms. This correlation combined topographic information with brightness information, resulting in an improvement of the current state of stratigraphic mapping of the NPLD, providing further evidence that layer sequences are continuous across the NPLD, and setting lower limits on relative accumulation rates for large sections of the cap.In order to search for a connection between the Martian paleoclimate and the NPLD stratigraphic record, I identified overlapping periodicities in the stratigraphic structure and compared them to periodicities in the climatic history, represented by the change in insolation with time at the North Pole over the last 5 Myr. I found that the ratio of stratigraphic wavelengths is systematically lower than the ratio between dominant modes of oscillation of the north polar insolation. However, a similar wavelet analysis of synthetic stratigraphic profiles created with a simple climate-driven model of accumulation revealed that a detectable non-linear relationship exists between the variation of insolation on the North Polar region of Mars and the stratigraphic record preserved in the NPLD. The dissertation is organized into four principal chapters and one final chapter with concluding remarks and future directions. Chapter 1 gives an introduction to Mars' polar regions and to the history of research in astronomically forced climate change through cyclostratigraphy, along with a short summary of the scope and main questions of this study. Chapter 2 details my study of the SPRC halos. Chapter 3 deals with the stratigraphic mapping of the NPLD through high-resolution topography, and Chapter 4 presents the results of my search for an astronomical forcing signal in the NPLD stratigraphy. Chapter 2 was published in the journal Icarus, in a special issue on the dynamic geologic processes of Mars and the science learned from continuous monitoring of these processes through remote sensing. Chapter 3 has been accepted for publication in the Journal of Geophysical Research. A modified version of Chapter 4 will be submitted to Nature Geoscience.
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Tellidis, Ioannis. "Preventing terrorism?" Thesis, University of St Andrews, 2008. http://hdl.handle.net/10023/426.
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This study examines the debates on nationalism, terrorism and conflict resolution, and intends to identify, on the one hand, the reasons why and the instances in which nationalist discourses usurp the notions of political violence and present it as a legitimate option for opposing a State, and on the other, whether there exist circumstances where conflict resolution techniques and approaches can be useful in isolating terrorist discourses from the nationalist ones, without necessarily criminalising the latter. The study employs a critical and discourse analysis approach to explaining ethno-nationalist and terrorist phenomena, arguing that a contextualisation of the nationalist and terrorist objects of study is necessary in order to comprehensively analyse the relationship between the two, and the instances where the former gives rise to the latter. The purpose of the study is to develop a theoretical framework for the understanding of nationalism and terrorism as interconnected practices, and looks into ways in which conflict resolution can intervene and prevent the infusion of the two. In order to test this framework, the thesis examines the Basque conflict and discusses how the discriminatory practices of the Francoist dictatorship towards the Basques played a catalytic role in their acceptance of violence as a legitimate vehicle of pursuit of the nationalist aim of independence, and how the radicalisation of counter-terrorist practices after the democratic transition further distanced the civil society from both the State and the militant group. The study analyses the role of the Basque civil society, and how it became the primary actor in the transformation of the conflict by rejecting violent practices from both the State and ETA, while at the same time promoting a more civic aspect of the Basque nationalist discourse. This attitude allows the thesis to conclude that, contrary to theories of conflict resolution, the State can combat terrorism most effectively when it allies with civil society in the alteration of perceptions that perpetuate violence, but instead favour a strictly political approach to the pursuit of political objectives, like self-determination.
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Armitage, Dominic Anthony. "High-resolution architectural evolution of depositional elements in deep-marine slope environments : the quaternary Niger delta slope, quaternary southwest grand banks slope, Canada, and Cretaceous Tres pasos formation, Chile /." May be available electronically:, 2009. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
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Partida, Sebastian. "La convention d'arbitrage dans le droit des nouvelles puissances économiques (Chine, Inde, Brésil, Mexique)." Thesis, Paris 2, 2019. http://www.theses.fr/2019PA020049.
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Les profondes mutations du commerce international, avec en particulier l'émergence de nouvelles puissances économiques et l’accélération de la révolution numérique, nous invitent à revoir les distinctions traditionnelles entre les différents droits de l'arbitrage. Si l'on peut observer un mouvement d'uniformisation des droits dans les pays occidentaux, en particulier avec une convergence des droits de Common Law et des droits continentaux, qu'en est-il dans les pays qualifiés hier d’ « émergents »? Assiste-t-on à ce même phénomène ? Des particularismes ressortent-ils? L'objet de cette thèse sera d'examiner les spécificités de quatre grands pays - la Chine, l’Inde, le Brésil et le Mexique - dont le poids démographique et économique ne cesse de croître dans les échanges internationaux. Dans une démarche comparative, nous nous intéresserons spécifiquement à la convention d'arbitrage, clé de voûte du droit de l’arbitrage, afin d’essayer de comprendre la philosophie et le traitement réservé à ce mode de règlement des différends dans chacun des ces pays. Cela nous conduira à nous interroger sur la place actuelle du droit français de l’arbitrage, longtemps considéré comme avant-gardiste, et sur son influence dans les années à venirThe profound changes in international trade, particularly in light of the emergence of new economic powers and the acceleration of the Digital Revolution, lead us to revisit the traditional distinctions between the different national arbitration laws. While a movement of standardization of national laws has been observed in Western countries, particularly with a tendency of convergence between Common Law and Civil Law jurisdictions, what about the countries that were qualified yesterday as "emerging"? Is the same phenomenon true for the them and Do particularisms emerge? The purpose of this thesis will be to examine the specificities of four major countries - China, India, Brazil and Mexico - whose demographic and economic weight is growing in international trade day by day. Through a comparative approach, we will focus specifically on the arbitration agreement, being the keystone of arbitration law, in order to try to understand the philosophy and treatment reserved to this dispute resolution method in each of these countries. This will inevitably lead to question the current place of French law, long considered as avant-garde, and its influence in the years to come
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Lindeby, Susanna. "Processes of feelings in a society with a violent past : A qualitative study of the communication for Societal healing in the Truth Commissions in East Timor, Sri Lanka and Ghana between 2002-2011." Thesis, Högskolan Dalarna, Statsvetenskap, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:du-13006.
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The research investigates in what extent and how communication for meeting feelings is provided in Truth Commission work. It examines if and in what way feelings are addressed in the communication officially published by the Truth Commissions in East Timor, Ghana and Sri Lanka, occurring between 2002-2011. The research is also looking at the healing processes in a time perspective to find out if there is a communication for Societal healing to be continued in a longer term. My conclusion is that two cases of three in my research, the TRCs in Ghana and East Timor, have communication clearly directed to meet feelings caused by the war. One of the three cases (East Timor) has a communication with a clear ambition to heal over a longer period, to continue after the existence of the Truth Commission. The research suggests that communication with a clear ambition to reach out widely in the society, a communication directed to meet and process feelings over a longer period, can make Societal healing more effective. It also concludes that, in the future, Societal healing, as a field in conflict resolution, will be more based on representational media than today, provided through web communication.
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Benigni, Paolo. "Trapped Ion Mobility Spectrometry coupled to Fourier Transform Ion Cyclotron Resonance Mass Spectrometry for the analysis of Complex Mixtures." FIU Digital Commons, 2017. https://digitalcommons.fiu.edu/etd/3547.
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Analytical Characterization of complex mixtures, such as crude oil, environmental samples, and biological mixtures, is challenging because of the large diversity of molecular components. Mass spectrometry based techniques are among the most powerful tools for the separation of molecules based on their molecular composition, and the coupling of ion mobility spectrometry has enabled the separation and structural elucidation using the tridimensional structure of the molecule. The present work expands the ability of analytical chemists by furthering the development of IMS-MS instrumentation by coupling Trapped Ion Mobility Spectrometry to Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (TIMS-FT-ICR MS). The TIMS-FT-ICR MS platform combines the high-resolution separation of TIMS, which has mobility resolving powers up to 400, and ultra-high mass resolution of FT-ICR MS, with mass resolving power over 1,000,000. This instrumentation allows the assignment of exact chemical composition for compounds in a complex mixture, as well as measurement of the collision cross-section of the molecule. Herein, the principles of the TIMS separation and its coupling to FT-ICR MS are described, as well as how the platform can be applied to targeted analysis of molecules, and untargeted characterization of complex mixtures.
Molecular standards were analyzed by TIMS-MS in order to develop a computational workflow that can be utilized to elucidate molecular structure, using the measured collision cross-section of the ion. This workflow enabled identification of structural, cis/trans isomers, and chelated molecules and provides the basis for unsupervised structural elucidation of a complex mixture, and in particular for the elucidation of hydrocarbons from fossil fuels. In summary, this work presents the coupling of TIMS-FT-ICR MS and provides examples of applications as a proof of concept of the potential of this platform for solving complex analytical challenges.
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Houenou, Emmanuel Sèmassa. "La contractualisation du droit des sociétés : l'ordre public à l'épreuve de la liberté contractuelle dans les sociétés commerciales de l'OHADA." Thesis, Paris 1, 2019. http://www.theses.fr/2019PA01D022.
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Dès l’adoption en 1997 de l’AUSC, le caractère d’ordre public des règles qui y sont éditées a été au cœur de maintes interrogations de la part des praticiens et de la doctrine. L'ensemble des dispositions de cet acte uniforme resté étaient déclarées d'ordre public par le législateur qui faisait ainsi un choix difficile à comprendre en ce qu’il s’inscrit totalement aux antipodes de la dynamique contemporaine. En effet, l’une des évolutions notables du droit des sociétés à la fin du 20e siècle est la tendance vers un droit souple dans laquelle la volonté des associés occupe une place de choix. On s'attend alors légitimement à une réforme de I'AUSC qui promeuve le recours dans la réglementation de leurs sociétés. Pourtant, depuis l'adoption de ladite réforme en Janvier 2014, la doctrine n'est pas unanime sur la portée du choix du législateur Ohada d'orienter le droit des sociétés dans le sens de la contractualisation. Ainsi, pendant que certains voient dans la réforme, un triomphe de la liberté contractuelle, d'autres n'y voient qu’une apparente consécration de l'autonomie de la volonté qui ne cacherait qu’un même droit rigide exclusivement constitué de règles d'ordre public. En tant que tel, il était opportun d’évaluer la portée du phénomène contractuel dans le droit des sociétés de l’Ohada et d’apprécier l’efficacité des mécanismes qui y concourent. Ainsi, en partant d’une analyse substantielle du droit positif, la présente étude a révélé un réel recul de l'ordre public sociétaire et un profond assouplissement du régime juridique des formes sociales jusque-là connues pour leur caractère institutionnel avéréSince the Uniform Act on General Commercial Law came into force in 1997, the public policy nature of the rules enacted has been questioned by practitioners and doctrine. All the provisions of this uniform act were declared mandatory by the legislator who made the difficult choice of diverting the contemporary trend. Indeed, one of the most significant developments in company law since the end of the 20th century is the move towards a flexible law in which the will of the shareholder is prominent. A reform of the Uniform Act on General Commercial Law then became necessary in order to allow the use of contractual mechanisms and adapt OHADA company law to the needs of shareholders.Yet since the law reform in January 2014, scholars are not unanimous on the extent which the OHADA legislator has stretched contract in company law. Thus, while some see the reform as a triumph of contractual freedom, others see it as a mere boost in party autonomy uphelding the same rigid law exclusively made of non deregatory rules. As such, it was appropriate to assess the scope of contractualism in OHADA company law as well as the effectiveness of the related contractual mechanisms. Focusing on a substantial analysis of existing laws, this contribution shows a real decline of public policy in company law and a deep flexibility in the legal regime of companies hitherto for their rigid institutional character
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Hamidouche, Louiza. "Spectroscopie micro-onde pour la mesure des charges d'espace à haute résolution spatiale dans les isolants en couche mince." Electronic Thesis or Diss., Sorbonne université, 2018. http://www.theses.fr/2018SORUS275.
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L'objectif de cette thèse est de proposer et de tester une nouvelle méthode pour la mesure des charges d'espace dans les isolants en couche mince avec une haute résolution spatiale. La méthode proposée est appelée Reflectométrie Électro-Acoustique ou en anglais Electro-Acoustic Reflectometry (EAR). La méthode EAR est basée sur le couplage électro-élastique de l'échantillon testé. L'excitation et la mesure sont électriques et se font dans le domaine fréquentiel. Une instrumentation micro-onde est employée pour des mesures à haute fréquence. Le principe de la mesure repose sur le fait que lorsque les charges sont excitées par un champ électrique appliqué, elles génèrent des ondes ultrasonores. L'énergie consommée par la génération de ces ondes produit une signature dans la réflexion par l'échantillon de l'excitation électrique. C'est cette signature qui est utilisée pour retrouver la distribution des charges d'espace par une simple transformée de Fourier inverse. Un banc de mesure composé d'un analyseur de réseaux vectoriel, d'un porte-échantillon dédié et d'une interface d'acquisition a permis de tester la méthode EAR. Les résultats obtenus sont prometteurs. La résolution spatiale démontrée est de 1.2µm en volume. Elle dépasse la meilleure résolution spatiale actuelle obtenue avec les méthodes ultrasonores conventionnelles existantes d'un facteur d'environ 10. Pour améliorer encore la résolution spatiale de la méthode EAR, il est nécessaire d'augmenter la plage de fréquences de mesure. Une approche est proposée pour résoudre les problèmes rencontrés à haute fréquenceThe objective of this thesis is to come up with and test a new method for the measurement of space charge in very thin insulating films with a high spatial resolution. The proposed method is called Electro-Acoustic Reflectometry (EAR) method. The EAR method relies on the electro-elastic coupling of the sample under test. Both excitation and measurement are of electrical nature and are performed in frequency domain. A microwave setup is used for high frequency measurements. The measurement principle is the generation of ultasonic waves when space charge undergoes an applied electrical field. The energy that is used up in the generation of these waves leaves a feature in the reflection of the electrical excitation. It is this feature that is used to find the space charge distribution by a simple inverse Fourier transform. A measurement setup comprising a vector network analyser, a dedicated sample holder and an acquistion interface allows to test the EAR method. The obtained results are promising. A bulk spatial resolution of 1.2µm has been demonstrated. It exceeds the current best spatial resolution achieved by existing conventionnal ultrasonic methods by a factor of about 10. To further enhance the spatiale resolution of the EAR method, it is necessary to broaden the measurement frequency range. An approach to deal with the problems occuring at high frequnecy is proposed
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Van, Exem Antonin. "Reconstructions de changements environnementaux dans les archives lacustres par imagerie hyperspectrale." Thesis, Normandie, 2018. http://www.theses.fr/2018NORMR101/document.
Full textAbstract:
Les lacs piègent des particules sédimentaires au fil du temps de manière à former des archives sédimentaires. Tracer l’origine des particules archivées avec une résolution stratigraphique particulièrement détaillée conduit à reconstituer une ou des informations paléoenvironnementales permettant d’identifier les changements environnementaux passés. Afin de décrypter ces informations, les techniques d’analyse des carottes sédimentaires nécessitent d’identifier des marqueurs de leur composition à haute résolution. L’imagerie l’hyperspectrale demeure une des rares techniques capables de représenter ces marqueurs en deux dimensions pour caractériser les variations de la composition du sédiment et les structures stratigraphiques les plus fines. Dans ce mémoire, le potentiel de l’imagerie est mis en valeur à travers l’étude de plusieurs cas. L’objectif est de reconstituer des changements environnementaux à partir de l’origine des matières organiques (MO) sédimentaires à hauterésolution rapidement et sans destruction des archives. Plusieurs marqueurs hyperspectraux permettant de comprendre l’origine des MO sont développés sur deux sites d’étude choisis pour leur potentielle signature organique sédimentaire. Dans un environnement méditerranéen, les apports en MO détritique dans les sédiments du lac Bresson tracent les épisodes d'incendie du couvert forestier alors que les variations de carbone organique total (COT) dans une série d’archives sédimentaires reconstruisent les fluctuations de l’érosion glaciaire dans un lac arctique. Dans ces deux cas, la MO d’origine détritique est tracée pour la première fois par une méthode non-destructive et le traçage de la MO issue de la productivitéprimaire aquatique (plus classique) est amélioré par un nouvel indice spectroscopique. Ces marqueurs sont validés par des méthodes utilisées en routine (HPLC, comptage des particules de charbon, pyrolyse Rock-Eval 6) puis calibrés par ces techniques pour reconstruire des concentrations en COT à haute résolution. L’imagerie hyperspectrale permet donc de tracer lacomposition sédimentaire, voire des variations géochimiques, pour quantifier l'origine des apports organiques. Ces résultats apparaissent comme prometteurs et fournissent les bases essentielles pour développer l'utilisation en routine de cette nouvelle technique afin de reconstituer finement les changements environnementaux passésOver time, lakes trap sedimentary particles that form sedimentary reserves. Tracing the origin of those particles with a precise stratigraphic resolution, involves reconstituting one or more paleo environmental information thus allowing the identification of past environmental changes. Decrypting that information requires a sedimentary carrot analysis technic to identify their high resolution composition indicators. Hyperspectral imagery remains one of the rare technics capable of showing those indicators in a two dimensional form so as to characterize the variations in the composition of the sediment as well as the finer stratigraphic structures. In comparison to the methods used routinely, hyperspectral imagery is a highresolution (nanometers resolution) technic that does not destroy the core of the sediment and is time efficient (1 hour per meter of sediment). In this thesis, the potential of the high resolution imagery is highlighted through the study of several case studies. The aim is to reconstitute environmental changes based on the origin of high resolution sedimentary organic matter (OM) quickly whilst preserving their history. Several hyperspectral indicators have been developed on two carefully chosen study sites to understand the origins of those OM. Those sites were chosen based on their potential sedimentary organic signature. In a Mediterranean environment, detrital OM inputs in the Bresson lake give a history of the various forest fires whereas the organic carbon variations in a series of reserve sediments, reconstruct the fluctuations of glacier erosion in an artic lake. In both cases, the OM of detrital origin is traced for the first time through a non-destructive method. Tracing OM issued from Primary aquatic production is improved with a new spectroscopic index. These indicators are validated by the methods routinely used (HPLC and RE6) then are calibrated by these technics in order to rebuilt high resolution COT concentrations. Hyperspectral imagery allows to trace the sedimentary composition and to see geo chemical variations in order to quantify the origin of organic inputs. Those results seem promising and bring essential foundations to develop the routine use of this new technic in order to reconstitute accurately past environmental changes
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Yemene, Tchouata Emerand. "La régulation de l'activité bancaire : contribution à l'étude de la stabilité du système bancaire dans les régions de la CEMAC, de l'UEMOA et de l'UE." Thesis, Paris 2, 2018. http://www.theses.fr/2018PA020023.
Full textAbstract:
La régulation bancaire doit être vue comme le fait d'encadrer et de contrôler l'activité bancaire, en la soumettant au respect des diverses normes, pour en maîtriser les risques afin de préserver la sécurité des déposants, la stabilité du système financier et les grands équilibres économiques. Pour arriver à cette fin, la régulation bancaire s'appuie essentiellement sur la réglementation et la supervision.Les systèmes bancaires domestiques étant devenus de plus en plus interdépendants, il apparaît nécessaire de faire face aux menaces de la même manière, de façon coordonnée au niveau international ou, à tout le moins, au niveau régional. C'est ainsi que la CEMAC et l'UEMOA se sont dotés au lendemain des crises de 1990 d'un dispositif de régulation marqué par une pléthore de réglementations et des organes de supervision communautaires. Depuis la crise de la dette survenue en Europe, la régulation de l'activité bancaire a évolué dans cette région avec la création de l'Union bancaire. Ceci dit, la supervision des établissements bancaires a été confiée à la Banque Centrale Européenne au sein de l' UE bien qu'elle demeure partagée avec les autorités nationales. Il s'agira pour nous, dans le présent travail, de comparer les dispositifs de régulation en vigueur dans les régions de la CEMAC, de l'UEMOA, de l'UE. On verra comment les régions de l'Afrique Centrale , de l'Afrique de l'Ouest et de l'Europe organisent la régulation bancaire en vue de préserver la stabilité des banques. Pour y parvenir il faudra comparer les différents organes chargés de la régulation et les principales règles de régulation qui existent dans ces régionsBanking regulation should be seen as the act of monitoring and controling banking, by subjecting the compliance with various standards to control risks to preserve the security of depositors , the stability of the financial system and major economic balances. To achieve this, the banking regulation is based mainly on regulation and supervision. Domestic banking systems have become increasingly interdependent, it is necessary to deal with threats in the same way , in a coordinated manner at the international level or at least at the regional level . Thus CEMAC and UEMOA have adopted in the aftermath of the 1990 crisis a control device marked by a plethora of regulations and community oversight bodies . Since the debt crisis in Europe, the regulation of banking has evolved in this region with the creation of the banking union . That said, the supervision of banks has been entrusted to the European Central Bank within the EU although it remains shared with the national authorities.In the course of this work, our task will be to compare the existing control devices in the CEMAC region , UEMOA , EU . We shall review and find how the regions of Central Africa, West Africa and Europe organize banking regulation in order to preserve the stability of their banks. To achieve this goal, a comparison of the various bodies responsible for the regulation and the main regulatory rules that exist in these regions are deemed necessary
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Raj, Jerry. "High Resolution Climate Simulations over Africa: Past, Present, and Future." Diss., 2019. http://hdl.handle.net/10754/660152.
Full textAbstract:
The horizontal resolution is a prominent constraint on the accuracy of simulating
synoptic and sub-synoptic scale rainfall. High resolution General Circulation Models
are signi cantly better than Regional Climate Models and conventional coarse resolution General Circulation Models in their representation of atmospheric circulation
and precipitation. In this study two monsoon systems over Africa, the features
associated with them, and their future are examined using a high resolution
Atmospheric General Circulation Model, HiRAM. HiRAM, which is developed at
Geophysical Fluid Dynamics Laboratory, employs a cubed-sphere nite volume dynamical core and uses shallow convective scheme for moist convection and stratiform
cloudiness instead of a deep convective parameterization. Future projections are conducted using the representative concentration pathway, RCP 8.5 from 2076 to 2099 at C360 ( 25 km)resolution. The study explores three important climate features of
the region: West African Monsoon, Southern African Monsoon, and African Easterly
Waves. These climate systems particularly bene t from high resolution simulations
since they involve several multiscale processes and are in uenced by coastlines and complex topography. The study shows that, in the RCP 8.5 scenario, elevated areas
of Sahel and western Sahara experience robust warming of >4K by the end of the
21st century. Precipitation increases over the equatorial Atlantic and the Guinean coast, while the southern Sahel appears drier. The wave activity of the region also shows a signi cant increase. The examination of the future projections of southern Africa reveals increased precipitation over central Africa and contrasting anomalies over northern Madagascar while Kalahari desert experience signi cant warming. The rainfall change in a global warming scenario is not unidirectional, unlike the temperature
which increases almost everywhere and this emphasizes the need for more projection studies.
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張宮槐. "The Design of Switched-Capacitor Low-pass Filter for High Resolution Delta-Sigma D/A Converter." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/70047872620264914458.
Full textAbstract:
碩士國立海洋大學
電機工程學系
91
In this thesis, a switched-capacitor filter is designed for stereo applications. The specification is set with resolution of 16-bit and signal bandwidth of 24KHz. The whole circuit includes an one-bit digital-to-analog converter and low-pass filter. One-bit digital-to-analog converter is a single-end to fully differential converter which is fed by the input bit stream. It is followed by the low-pass filter. The realized low-pass filter is composed by the cascade of a third-order switched capacitor (SC) section and a first-order RC active section. The third-order SC filter is composed by the cascade of second-order (SC) filter and first-order (SC) filter. The use of third-order SC filter guarantees a good accuracy in the frequency and reduces the effects of the bit-stream nonidealities (like clock jitter and inaccurate edges). The first-order continuous-time filter allows the smoothing of SC filter output signal and accomplishes the final fully differential to singled-end transformation. The whole filter is simulated by MATLAB first. It is possible to gain loss (-3dB) at 50kHz. The switched-capacitor filter’s signal-to-noise ratio is over 71 dB, that is simulated with HSPICE. Finally, signal-to-noise ratio from the variation of input signal frequency would be analyzed and observe their relationship. The SC filter sample rate is 6.144MHz, the power supply is 3V. The fabrication technology is TSMC 0.25um 1P5M technology for SC filter.
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Zhao, Zhijun. "High speed multiple-pass cavity scanning optical delay line for real-time high resolution optical coherence tomography (OCT)." Thesis, 2005. http://spectrum.library.concordia.ca/8794/1/MR14291.pdf.
Full textAbstract:
Firstly, the basic theory of the optical coherence tomography (OCT) is reviewed. Optical delay line is one of important parts in OCT. Several types of optical delay lines which were proposed and demonstrated are briefly described including their advantages and disadvantages. In this work, a novel multiple-pass cavity optical delay line (MPC-ODL) is proposed and analyzed. The proposed delay line consists of four mirrors, one lens and one resonant scanner. In this proposed delay line, the path delay is obtained by scanning a tilting mirror and magnified by the multiple-pass optical cavity. Thus, for a small scanning angle, a large path delay can be obtained. This delay line is especially suitable for the OCT system that will generate the large dimension images at video rate with high resolution. However, due to multiple-pass cavity used in the proposed delay line, false interference signal may be created besides OCT signal. In order to reduce the false interference signal generation, some crucial parameters of the proposed delay line have to be carefully chosen. Principle of how to choose the optical component parameters is given. The proposed delay line combined with OCT is verified by computer simulation. Characterization of the delay line is done by simulation and it is shown that the scanning repetition rate of 16 kHz, the total path delay of 3 mm, and the scan velocity of 71.3 m/s can be achieved. The proposed delay line can support OCT system with dynamic range over 110 dB. The proposed delay line can support a further higher scanning repetition rate, such as 32kHz
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Tsao, Bor-Shiun, and 曹博勛. "High resolution Hand-held Computer as a Portable PACS Terminal using Wireless LAN." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/12119938271055131082.
Full textAbstract:
碩士國立交通大學
資訊科學系
90
The PACS plays a very important role in medical diagnosis in recent years. More and more hospitals use PACS instead of traditional X-ray films. Some hospitals also integrate their HIS-RIS with PACS to become an integrated diagnosis information system. Using such a system can not only guarantee quality of the medical images but also effectively reduce the space needed to store the medical images. Furthermore, hospitals will become more efficient because the integration of these information systems. Although using PACS will take hospitals so many advantages, there are still some problems during ward round. Because it is impossible placing PACS terminals in each sickroom, doctors need to take hundreds of X-ray films during ward round. In order to resolve the problem, we develope a portable PACS terminal system using high resolution tablet PC to display medical images from the PACS via wireless network communication. Besides, we provide some image display functions like window/level setting, zoom and window fitting, rotating, measurement and annotation to assist doctors in making diagnosis. With this system doctors can take a tablet PC instead of numerous X-ray films and increase efficiency and quality of ward round.
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Huang, Chen-yu, and 黃振祐. "High-resolution Paleoceanography / Paleoclimate fluctuation records from the Okinawa trough cores for the past 40kyrs." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/20759109394658625460.
Full textAbstract:
碩士國立臺灣師範大學
地球科學研究所
90
Two deep-sea cores(MD982195, 31°38.33’N, 128°56.63’E, water depth 746m; CSH-2, 29°25.0’ N, 126°34’ E, water depth 703m) retrieved from the Okinawa Trough, Western Pacific were studied to unravel the high resolution (65-90 years; 30-140 years, respectively) paleoceanography and paleoclimate records of the Okinawa Trough for the last 40 kyrs. Proxies adopted in this study include alkenone index, carbonate fraction, and organic carbon content. Core MD982195 (33.6 m long) shows continuous and homogenous sedimentation with two vocanic ash layers. The length of core CSH-2 is 7.3 m. Several 14C datings together with planktonic foraminiferal δ18O stratigraphy show the bottom of the cores are respectively down to stage 3(MD982195) and stage 2(CSH-2) in the last glacial period. Carbonate stratigraphy in both cores shows the typical Atlantic pattern, which the carbonate content is high in the interglacial period and low in glacial time. Terrestrial organic matter concentration increase in the glacial period giving this area planty of nutrient. Obviously, the sedimentation character of the Okinawa Trough is heavily influenced by terrigeous input and its dilution effect. This trend is the same as those records recorded in other five cores along the western Pacific marginal seas. The organic carbon content in both cores are quite high compare with other records in the South China Sea and Okinawa Trough. This is probably because of great terrestrial organic matter input and the water depth of the cores falls in the oxygen minimum zone in the water column where always have better preservation in organic matter. The paleo-sea surface temperature (SST) record which is almost parallel with oxygen isotope curve shows that the SST of glacial time was about 5℃ cooler than that of interglacial time in the Okinawa Trough. Similar to other records of northern hemisphere, the lowest paleo-SST occurred at 17-18 ka in the last glacial maximum. The millennial paleo-SST fluctuation magnitude decrease gradually since the glacial period of time. The magnitude reaches 2℃ before IS. 8 but only 0.5℃ in the interglacial period of time. When we compare the record with oxygen isotope record, we can find there are several salinity change events in the last 40kyrs, which might be related to the input of the fresh water from China continent. The record also shows that there are two special paleo-SST change events. One is a 2℃ cooling event occure at 800-1500BP which is the same magnitude as the Younger Dryas event. The other is a warming event around 9000 BP, which might be the result of the strengthen of the Kuroshio current or regional hydrothermal effect. Both of them needs to be further studied.
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Reyes, Dasia Ann. "Advancing the Theoretical Foundation of the Partially-averaged Navier-Stokes Approach." Thesis, 2013. http://hdl.handle.net/1969.1/149535.
Full textAbstract:
The goal of this dissertation is to consolidate the theoretical foundation of variable-resolution (VR) methods in general and the partially-averaged Navier-Stokes (PANS) approach in particular. The accurate simulation of complex turbulent flows remains an outstanding challenge in modern computational fluid dynamics. High- fidelity approaches such as direct numerical simulations (DNS) and large-eddy simulation (LES) are not typically feasible for complex engineering simulations with cur- rent computational technologies. Low-fidelity approaches such as Reynolds-averaged Navier-Stokes (RANS), although widely used, are inherently inadequate for turbulent flows with complex flow features. VR bridging methods fill the gap between DNS and RANS by allowing a tunable degree of resolution ranging from RANS to DNS. While the utility of VR methods is well established, the mathematical foundations and physical characterization require further development.
This dissertation focuses on the physical attributes of fluctuations in partially-resolved simulations of turbulence. The specific objectives are to: (i) establish a framework for assessing the physical fidelity of VR methods to examine PANS fluctuations; (ii) investigate PANS simulations subject to multiple resolution changes; (iii) examine turbulent transport closure modeling for partially-resolved fields; (iv) examine the effect of filter control parameters in the limit of spectral cut-off in the dissipative region; and (v) validate low-Reynolds number corrections with RANS for eventual implementation with PANS. While the validation methods are carried out in the context of PANS, they are considered appropriate for all VR bridging methods.
The key findings of this dissertation are summarized as follows. The Kolmogorov hypotheses are suitably adapted to describe fluctuations of partially-resolved turbulence fields, and the PANS partially-resolved field is physically consistent with the adapted Kolmogorov hypotheses. PANS adequately recovers the correct energetics in instances of multiple resolution changes. Scaling arguments are used to determine the correct transport closure model for a partially-resolved field in a boundary layer. The need to modify the fε filter control parameter for cut-off in the dissipation range is highlighted. A low-Reynolds number near-wall correction was evaluated on a RANS model with the intent of adapting to it VR methods. Overall, PANS shows promise as a theoretically sound modeling approach, and this work lays the foundation for future PANS investigations.
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Taylor, Brandon L. "A Speleothem-Based High Resolution Reconstruction of Climate in Southeastern Brazil Over the Past 4,100 Years." 2010. https://scholarworks.umass.edu/theses/390.
Full textAbstract:
Isotopic investigations of speleothem CR1 from Cristal Cave in southeastern Brazil have established a high-resolution record of climate change extending 4,100 years prior to sample collection in 2007. A total of 14 subsamples were collected from CR1 for U/Th age determination. ICP-MS analysis yielded very precise ages with analytical errors (2σ) averaging ± 13 years. An initial growth rate of .062 mm y-1 for the first 2860 years is followed by a rate of .08 mm y-1 for the remaining growth period allowing for sampling of δ18O at sub-decadal resolution. Stable isotope analyses show a large range of δ18O values between -7.5 ‰ to -4 ‰. The data show a trend of steadily decreasing values over the past 4,000 y BP. The exception to this trend is the last 150 years BP when some of the least negative and most variable values for the record are observed.
Variations in speleothem δ18O in southern Brazil have been shown to reflect changes in rainfall δ18O, which in turn indicate changes in rainfall source or rainfall amount (Cruz et al., 2006). In Southeastern Brazil, δ18O is controlled mainly by moisture source location, in particular South American monsoonal versus extratropical sources (Cruz et al., 2005). The relative contribution of monsoonal and extratropical moisture help to define the δ18O of regional precipitation via the mean location and southward extent of Hadley cell convective activity associated with the South American summer monsoon (Cruz et al., 2005). For example, decreases in precipitation δ18O are often interpreted as a decreased contribution of winter versus summer precipitation (Cruz et al., 2005). Assuming that the modern (observed) relationship between the seasonality and moisture source location effect occurring in southeastern Brazil have functioned for the past ~ 4,100 years, trends of more negative values towards modern day are likely due to increased summer precipitation and/or an overall increase in total yearly precipitation. The more enriched values of the past 100 years suggest a recent decrease in summer and/or total rainfall.
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LEE, WANG JIE, and 李王家. "The Study of Constructure Resolution and Reaction Mechanism Research of PAHs Using Dibenzo(a,e)fluoranthene." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/76828903033666344009.
Full text
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Hsu, Yuam-Cheng, and 許元正. "Method Development of Thermal Desorption Combined with High-Resolution Gas Chromatography Mass Spectrometry for Measuring PAHs in PM2.5." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/99v444.
Full textAbstract:
碩士國立中央大學
環境工程研究所
106
PM2.5, known as respirable aerosol contains heavy metals and organic pollutants. PM2.5 may such as PAHs and Dioxins reach human alveoli when inhaled. The soluble contaminants in the particles are easily absorbed by the blood and endanger human health. Polycyclic aromatic hydrocarbons (PAHs) are common pollutants in the environment. Because many of them are definite or potential carcinogens, they have received great attention by the international community such as the World Health Organization (WHO). PAHs and PM2.5 have a common source such as combustion and vehicle exhaust. Therefore, they are easily combined and cause synergistic effect on human health. In the past, investigations on the airborne fine aerosol matrix mostly concentrated on the mass concentration of PM2.5. Studies on the pollutants such as PAHs existing on PM2.5 are limited due to low the detection limit of the analytical method (MDL) and the requirement of a large amount of sample acquisition, leading to prolonged sampling time and complicate pretreatment processes. Due to the difficulty compared to other environmental matrices, investigations on the PAHs in PM2.5 are limited. It is imperative to develop analytical techniques with lower MDL to overcome the sampling bottlenecks such that comprehensive air quality survey can be conducted for the assessment of human health hazards. In this study, thermal desorption technology is applied to directly introduce the PAHs in the PM2.5 into GC/HRMS for the analysis to significantly reduce the pretreatment processes steps and lower MDL, thereby reducing analysis loss and sampling time. The MDLs of the 27 PAHs in this study are in the range of 0.34 to 23.2 pg/m3, which can effectively detect highly toxic PAHs in the atmosphere, providing more accurate data for risk assessment. Pneliminary results indicate that the concentrations of solid-phase PAHs in ambient air of northern, central and eastern Taiwan are in the range of 0.13-6.63 ng/m3 and the average concentration is 2.23 ng/m3. The PAH concentration measured in winter is higher than that in summer, and the concentration per unit mass of PM2.5 range from 0.071 to 0.280 ng/μg and the average concentration is 0.133 ng/μg. In the future, this technology can be applied for the investigation of persistent organic pollutants (POPs) on fine particles.
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Juan, Tzu-Chi, and 阮子齊. "Track deflection of Typhoon Maria (2018) past Taiwan under Topographical Influences as Investigated by High-Resolution Global Model FV3GFS." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/rkf843.
Full textAbstract:
碩士國立中央大學
大氣科學學系
107
Global model FV3GFS, which has been chosen as the Next Generation Global Prediction System, provides a “grid stretching” technique which could not only increase resolution in the specific area but also keep its computational efficiency at the same time. In this study, we ap-plied this technique to simulate typhoon Maria (2018) with 7 km resolution. The results revealed that FV3GFS had capability of better typhoon track forecast. Compared to other agencies, translation speed and typhoon track deflection could be captured by the model well. Based on the previous results, we took advantages of FV3GFS to investigate the dynam-ical processes between Taiwan terrain and typhoon Maria. After removing terrain in Taiwan, we found that the northern deflection and the change of wind speed vanished. The results suggested that the terrain might lead to change in the path of typhoon and increase in wind speed around the radius of maximum wind (RMW). In this study, momentum and angular momentum (AM) tendency budget was preformed to verify the wind speed change, and we found that the strong inflow occurred below the planetary boundary layer, which transported the larger AM into the center and then enhanced the tangen-tial wind near eyewall. Meanwhile, outer part of the typhoon produced negative radial eddy advection, which slowed down the wind speed. Furthermore, vorticity tendency budget was performed to verify the track deflection. During the northern deflection of the typhoon track, we found that the northern deflection of the typhoon track was mainly caused by the horizontal ad-vection, and the sum of other terms decelerated the translation speed of the typhoon. Through these serial analyses, it turned out that the northern deflection of the typhoon track was primarily caused by terrain blocking, which produced a split flow to change the steering flow when ty-phoon was passing through the northwest of Taiwan ocean. The intensification near the eyewall was resulted from the larger AM advection, which was also caused by the split flow from outer part of the typhoon.
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Bringué, Manuel Alain. "High resolution dinoflagellate cyst sedimentary records of past oceanographic and climatic history from the Northeastern Pacific over the last millennium." Thesis, 2015. http://hdl.handle.net/1828/6407.
Full textAbstract:
This thesis contributes to the development of dinoflagellate cysts as indicators of past environmental change in the Northeastern Pacific coastal ocean, and investigates past variations in sea-surface temperature, salinity and primary productivity encoded in dinoflagellate cyst sedimentary records from the Santa Barbara Basin (SBB, southern California) and Effingham Inlet (Vancouver Island, British Columbia) over the last millennium. The dinoflagellate cyst records extracted from the SBB and Effingham Inlet predominantly laminated sediments and analysed at sub-decadal resolutions, constitute some of the most detailed records of cyst-producing dinoflagellate populations in the world.
A two year-long sediment trap study from the SBB documents the seasonality in dinoflagellate cyst production for the first time on the Pacific coast of the United States. The study shows that dinoflagellate cyst data can be used as indicators of changes in sea-surface temperature and primary productivity associated with seasonal upwelling in the SBB. In particular, several dinoflagellate cyst taxa such as Brigantedinium spp. and Lingulodinium machaerophorum are identified as indicators of “active upwelling” (typically occurring in spring and early summer) and “relaxed upwelling” conditions (fall and early winter) at the site, respectively.
Analysis of a dinoflagellate cyst record from the SBB spanning the last ~260 years at biannual resolution documents the response of cyst-producing dinoflagellates to instrumentally-measured warming during the 20th century, and reveals decadal scale variations in primary productivity at the site that are coherent with phases of the Pacific Decadal Oscillation (PDO). The cyst assemblages are dominated by cysts produced by heterotrophic dinoflagellates (in particular Brigantedinium spp.), but the turn of the 20th century is marked by an abrupt increase in concentrations of L. machaerophorum and Spiniferites ramosus, two cyst taxa of autotrophic affinity. Their increasing abundances during the 20th century are interpreted to reflect warmer conditions and possibly stronger stratification during summer and fall. The dinoflagellate cyst data suggest a warming pulse in the early 1900s and provide further evidence that persistently warmer and/or more stratified conditions were established by the late 1920s.
The dinoflagellate cyst record from Effingham Inlet, spanning the last millennium, is characterized by the proportionally equal contribution of cysts produced by autotrophic and heterotrophic dinoflagellates in most samples. The cyst data indicate variations in sea-surface temperature, salinity and primary productivity that are associated with local expressions of the Medieval Climate Anomaly (from the base of the record to ~1230), the Little Ice Age (from ~1230 to ~1900) and warming during the second half of the 20th century.
Both dinoflagellate cyst records reveal that since the beginning (in the SBB) and mid-20th century (in Effingham Inlet), autotrophic dinoflagellates contribute to a greater portion of the primary production in the region, whereas heterotrophic dinoflagellates, as indicators of diatom populations, decline. Variability in the dinoflagellate cyst data is coherent at both sites and suggest a reduced expression of decadal scale variability associated with the PDO during the 19th century.Graduate
0416
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mbringue@uvic.ca
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Chen, Kuo-Hang, and 陳國航. "High-resolution geomagnetic secular variation record around Taiwan for the past 2,000 years: A case study of marine core MD05-2907 in southern Okinawa Trough." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/78853235291802244259.
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"High-resolution architectural evolution of depositional elements in deep-marine slope environments: The Quaternary Niger Delta slope, Quaternary southwest Grand Banks slope, Canada, and Cretaceous Tres Pasos Formation, Chile." STANFORD UNIVERSITY, 2009. http://pqdtopen.proquest.com/#viewpdf?dispub=3351485.
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