• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 186
  • 79
  • 77
  • 28
  • 23
  • 11
  • 9
  • 6
  • 6
  • 6
  • 5
  • 5
  • 3
  • 3
  • 2
  • Tagged with
  • 505
  • 285
  • 79
  • 65
  • 50
  • 50
  • 43
  • 43
  • 42
  • 41
  • 35
  • 30
  • 29
  • 28
  • 27
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
441

Implementation of high-resolution direct push sensing in geoarchaeological exploration of wetland sites

Rabiger-Völlmer, Johannes 07 February 2024 (has links)
Wetland sites provide important knowledge about settlement history and historical infrastructure in the form of buried archaeological features. However, the subsurface is difficult to access, e.g. due to high groundwater levels or unstable sediments, making archaeological excavation difficult and the conservation of recovered artefacts, e.g. timbers, is expensive. In addition, one of the aims of heritage conservation is to disturb structures in such contexts as little as possible as part of preserving. Therefore, alternative non- and minimal-invasive methods, e.g. geophysical prospection and vibra-coring, are used for exploration. However, geophysical surveys face the issue of inaccurate depth values and rely on sufficient contrasts in the measured physical parameters. Vibra-coring allows direct access to the sediments, but again gives inaccurate depth values due to high compaction rates. For this reason, the implementation of alternative methods and the development of new methodical approaches to wetland site exploration are of extraordinary importance. One such wetland site is the Fossa Carolina, an early medieval canal that today is partially buried. Located in Southern Germany next to Treuchtlingen, south of Nuremberg, the canal was intended at the time to provide a navigable link between the Rhine-Main and Danube basins by bridging the European watershed. In the research for this thesis, direct push sensing was used as an alternative exploration technique to explore the site. In this method, various probes are pushed into the unconsolidated subsoil and the parameters are measured in situ with high depth accuracy. (i) Therefore, the colour logging tool (CLT) and the electrical conductivity (EC) probe were applied. (ii) In order to record archaeological structures and features, the soundings were distributed closely along a transect using an adaptive exploration strategy, thus recording a high-resolution cross-section of the structure. (iii) These prospections were integrated into a spatial-hierarchical multi-method approach by combining direct push sensing with geophysical survey and vibra-coring, inter alia. (iv) Thus, a deeply buried section of the Fossa Carolina (West-East Section) was explored, demonstrating at least one-way navigability and revealing the backfill stratigraphy. (v) Furthermore, the approach used helped to clarify the nature of conspicuous magnetic anomalies in the area adjacent to the canal. In the Northern and North-Eastern Sections, magnetic anomalies provided evidence of water-supplying structures. The exploration of these structures revealed an Early Holocene structure in the North-Eastern Section and a historic gravel road in the Northern Section. (vi) Additionally, a strong magnetic anomaly with a course parallel to the canal in the Northern Section could be temporally and stratigraphically associated with the construction of the canal. Thus, for the first time, a larger remnant of the construction process outside the canal could be identified, even if the origin could not be conclusively clarified. (vii) In a broader context, the in situ direct push cross-sections were integrated into a 3D modelling approach for the entire Fossa Carolina to quantify the excavation volume. (viii) The methodological approach was successfully applied to a wetland site at Pestenacker in Southern Germany to collect evidence for Holocene floodplain dynamics in the Late Neolithic settlement. Finally, the thesis demonstrates the enormous methodological potential of direct push sensing for the exploration of buried archaeological sites. In particular, the colour logging tool is proving to be extremely effective, further enhanced by the intelligent combination in multi-method approaches. This is confirmed by the significant results obtained at Fossa Carolina that shed new light on the canal{'}s navigability, water supply, and construction structure. Overall, this thesis demonstrates the valuable contribution that direct push methods can make to geoarchaeological research. It both introduces a new methodological approach and provides new empirical evidence concerning the construction of an example of early medieval infrastructure.:Preface Acknowledgements Abstract Kurzfassung Contents List of Figures List of Tables Acronyms and Symbols 1 Introduction 1.1 Geoarchaeological exploration in wetlands: possibilities and challenges 1.1.1 Proven exploration methods 1.1.2 Direct push sensing 1.1.3 Exploration strategies 1.2 The study site 1.2.1 The Fossa Carolina - State of the art in brief 1.2.2 Natural settings 1.3 Aims of the thesis 2 Published Studies 2.1 Minimalinvasive Direct-push-Erkundung in der Feuchtboden(geo)archäologie am Beispiel des Karlsgrabens (Fossa Carolina) 2.2 Non-invasive prospection techniques and direct push sensing as high-resolution validation tools in wetland geoarchaeology – Artificial water supply at a Carolingian canal in South Germany? 2.3 High-Resolution Direct Push Sensing in Wetland Geoarchaeology—First Traces of Off-Site Construction Activities at the Fossa Carolina 2.4 3D-Modelling of Charlemagne’s Summit Canal (Southern Germany)—Merging Remote Sensing and Geoarchaeological Subsurface Data 2.5 A hydrological tipping point and onset of Neolithic wetland occupation in Pestenacker (Lech catchment, S Germany) 3 Discussion 3.1 Direct push sensing for wetland exploration 3.1.1 High-resolution direct push sensing cross-sections 3.1.2 Integration and comparison of direct push sensing in a spatially hierarchical multi-method approach 3.1.3 Direct push colour logging tool (CLT) data for ground truthing 3.1.4 Perspectives on direct push sensing in geoarchaeology 3.2 Results of the exploration of the Fossa Carolina 3.2.1 Chronostratigraphic recording in the West-East and Northern Sections 3.2.2 Characteristics of the canal construction in the West-East and Northern Sections 3.2.3 Validation of off-canal structures in the Northern and North-Eastern Sections 3.2.4 Water supply for the Fossa Carolina 3.2.5 Pending issues in the study of the Fossa Carolina 4 Conclusion References Appendix A1 - Author publications A2 - Article contribution A3 - Declaration of originality A4 - Bibliographic description / Feuchtgebiete bergen durch begrabene archäologische Strukturen wichtige Erkenntnisse zur Siedlungsgeschichte und historischen Infrastruktur. Schwierige Untergrundverhältnisse, z. B. durch hohen Grundwasserspiegel oder instabile Sedimente, erschweren jedoch archäologische Ausgrabungen und die Konservierung der geborgenen Artefakte, z. B. Hölzer, verursacht hohe Kosten. Darüber hinaus ist ein Ziel der Bodendenkmalpflege, archäologische Strukturen so wenig wie möglich zu beeinträchtigen und sie in situ zu erhalten. Daher werden alternative nicht- und minimal-invasive Methoden, z. B. geophysikalische Prospektionen und Rammkernsondierungen, zur Exploration eingesetzt. Bei geophysikalischen Untersuchungen ergeben sich jedoch Schwierigkeiten durch ungenaue Tiefenwerte und die Methoden sind auf ausreichende Kontraste der gemessenen physikalischen Parameter angewiesen. Rammkernsondierungen ermöglichen einen direkten Zugriff auf die Sedimente, erzeugen jedoch wiederum ungenaue Tiefenwerte durch hohe Kompaktionsraten. Aus diesem Grund sind die Implementierung alternativer Methoden und die Entwicklung neuer methodischer Ansätze für die Erforschung von Feuchtgebietsstandorten von herausragender Bedeutung. Die Fossa Carolina, ein frühmittelalterlicher, heute teilweise verschütteter Kanal, ist ein solcher Standort. Das Bauwerk befindet sich in Süddeutschland in der Nähe von Treuchtlingen, südlich von Nürnberg und sollte eine schiffbare Verbindung zwischen dem Rhein-Main- und dem Donaueinzugsgebiet herstellen, indem es die europäische Hauptwasserscheide überbrückte. Zur Erkundung des Bauwerks wurde als Alternative die in situ Direct-Push-Methode eingesetzt. Bei dieser Methode werden verschiedene Sonden in den unkonsolidierten Untergrund gedrückt und die Parameter in situ tiefengenau gemessen. (i) Dabei kamen die Farbsonde, engl. colour logging tool (CLT), und die Sonde zur Messung der elektrischen Leitfähigkeit, engl. electrical conductivity (EC) probe, zum Einsatz. (ii) Zur Erfassung archäologischer Strukturen und Befunde wurden die Sondierungen mit einer adaptiven Erkundungsstrategie auf einem Transekt engmaschig verteilt und somit ein hochaufgelöster Querschnitt des Bauwerks erfasst. (iii) Darüber hinaus wurden diese Prospektionen in einen räumlich-hierarchischen Multimethodenansatz integriert, indem in situ Direct-Push-Sondierungen mit z. B. geophysikalischen Erkundungen und Rammkernsondierungen kombiniert wurden. Somit wurde (iv) ein tiefliegender, begrabener Abschnitt der Fossa Carolina im West-Ost-Bereich erkundet, dort die Schiffbarkeit für mindestens eine Schiffsbreite nachgewiesen und die Sedimentstratigraphie der Verfüllung beschrieben. Weiterhin wurde der Ansatz genutzt, um magnetische Anomalien im Umfeld des Kanals zu prospektieren. (v) Im nördlichen und nordöstlichen Bereich lieferten magnetische Anomalien Hinweise auf wasserzuführende Bauwerke im Untergrund. Die Erkundung ergab eine frühholozäne Struktur im nordöstlichen Bereich und eine historische Schotterstraße im nördlichen Bereich. (vi) Weiterhin konnte eine starke magnetische Anomalie mit parallelem Verlauf zum Kanal im nördlichen Bereich zeitlich und stratigraphisch dem Bauwerk zugeordnet werden. Somit konnte zum ersten Mal eine größere Spur des Baus außerhalb des Kanals nachgewiesen werden, auch wenn die Entstehung nicht abschließend geklärt werden konnte. (vii) Im übergeordneten Kontext konnten die Daten der in situ Direct-Push-Transekte in einen 3D-Modellierungsansatz für die gesamte Fossa Carolina zur Quantifizierung des Aushubs integriert werden. (viii) Neben der Erforschung der Fossa Carolina wurde der methodische Ansatz zusätzlich an einem Feuchtgebietsstandort bei Pestenacker in Süddeutschland angewendet, um Informationen über die holozäne Auendynamik an der spätneolithischen Siedlung zu gewinnen. Schlussendlich belegt die Dissertation das enorme methodische Potential der in situ Direct-Push-Erkundungen für die Prospektion von Bodendenkmälern. Dabei erweist sich insbesondere die Farbsonde als äußerst wirkungsvoll, was durch die gezielte Kombination in multi-methodischen Ansätzen noch verstärkt wird. Dies wird durch die aussagekräftigen Ergebnisse an der Fossa Carolina belegt, mit deren Hilfe insbesondere neue Erkenntnisse zur Schiffbarkeit, Wasserzuführung und Baustruktur gewonnen werden konnten. Insgesamt demonstriert diese Dissertation den wertvollen Beitrag, den in situ Direct-Push-Methoden zur geoarchäologischen Forschung leisten können. Sie präsentiert sowohl einen neuen methodischen Ansatz als auch neue empirische Erkenntnisse zu einem frühmittelalterlichen Bauwerk.:Preface Acknowledgements Abstract Kurzfassung Contents List of Figures List of Tables Acronyms and Symbols 1 Introduction 1.1 Geoarchaeological exploration in wetlands: possibilities and challenges 1.1.1 Proven exploration methods 1.1.2 Direct push sensing 1.1.3 Exploration strategies 1.2 The study site 1.2.1 The Fossa Carolina - State of the art in brief 1.2.2 Natural settings 1.3 Aims of the thesis 2 Published Studies 2.1 Minimalinvasive Direct-push-Erkundung in der Feuchtboden(geo)archäologie am Beispiel des Karlsgrabens (Fossa Carolina) 2.2 Non-invasive prospection techniques and direct push sensing as high-resolution validation tools in wetland geoarchaeology – Artificial water supply at a Carolingian canal in South Germany? 2.3 High-Resolution Direct Push Sensing in Wetland Geoarchaeology—First Traces of Off-Site Construction Activities at the Fossa Carolina 2.4 3D-Modelling of Charlemagne’s Summit Canal (Southern Germany)—Merging Remote Sensing and Geoarchaeological Subsurface Data 2.5 A hydrological tipping point and onset of Neolithic wetland occupation in Pestenacker (Lech catchment, S Germany) 3 Discussion 3.1 Direct push sensing for wetland exploration 3.1.1 High-resolution direct push sensing cross-sections 3.1.2 Integration and comparison of direct push sensing in a spatially hierarchical multi-method approach 3.1.3 Direct push colour logging tool (CLT) data for ground truthing 3.1.4 Perspectives on direct push sensing in geoarchaeology 3.2 Results of the exploration of the Fossa Carolina 3.2.1 Chronostratigraphic recording in the West-East and Northern Sections 3.2.2 Characteristics of the canal construction in the West-East and Northern Sections 3.2.3 Validation of off-canal structures in the Northern and North-Eastern Sections 3.2.4 Water supply for the Fossa Carolina 3.2.5 Pending issues in the study of the Fossa Carolina 4 Conclusion References Appendix A1 - Author publications A2 - Article contribution A3 - Declaration of originality A4 - Bibliographic description
442

Skellefteås återkomst : En fallstudie om migrationsmönster och urbana effekter under en industriell expansion / The Return of Skellefteå : A case study of migration patterns and urban effects during an industrial expansion

Kokkalis, Elena, Adler, Rebecca January 2022 (has links)
Idag står världen inför nya typer av utmaningar för att möta hållbarhetsmål och nya behov somuppkommer. Många städer genomgår därför stora förändringar i utvecklingen där både förväntadeoch oväntade konsekvenser kommer att uppstå. Sedan Northvolt beslutade att etablera sig iSkellefteå år 2017, står staden inför den stora möjligheten att bli en pionjär stad för grön utveckling.Den nya utvecklingen har inte bara satt industrin på prov, utan även staden som helhet. Kommunensutmaning är att sprida budskapet om vad den kommande utvecklingen har att erbjuda, i hopp om attsätta fart på inflyttningen då kompetensbehovet är Skellefteås främsta utmaning idag. För att mötavisionerna kring utvecklingen behöver alla aktörer samverka för att bli en stad för grön elektrifiering.Välfungerande socialt kapital mellan offentlig sektor, industri, akademi och medborgare är enförutsättning för att skapa en framgångsrik utveckling.Arbetet utforskar hur en stad som genomgår en omfattande och snabb industriell expansionpåverkas. Genom att studera migrationsmönster ur “push and pull”-teorin undersöker arbetet hur detär möjligt att generera en ökad in-migration i olika målgrupper, som studenter eller hemvändare.Samtidigt som Skellefteå är beroende av att ha ett positiv inflyttningsnetto behöver även denuvarande invånarna bibehållas. Därför har intervjuer och en enkät genomförts för att få en tydligbild av styrkor och svagheter i utvecklingen av Skellefteå. Resultaten av enkäten och intervjuernaanalyserades och diskuterades genom en exemplifiering av de två teorierna push and pull och teorinom socialt kapital.Stora industriella expansioner av denna storlek skakar städerna till sin kärna, eftersom stadensidentitet och attribut ifrågasätts under denna typ av förändring. Vid en utveckling av denna storleksätts det sociala kapitalet på prov och beroende på dess effektivitet kan utfallen skilja sig åt. Stadentvingas väga olika faktorer mot varandra; ekonomiska, sociala och miljömässiga, då alla inte är möjligaatt upprätthålla till samma grad. Eftersom det största målet är att skapa en ökad in-migration till denexpanderande staden måste de pull-faktorer som finns och främjas ifrågasättas; Vad erbjuderegentligen Skellefteå? Arbetet identifierade sex möjliga grupper av in-migration; kontraurbanister,livsstilsmigranter, människor som flyttar för relationer/hemvändare, människor som flyttar förjobbmöjligheter, studenter och människor som flyttar för hållbarhetsskäl. Genom att lyfta fram enuppsättning av pull-faktorer specifikt för Skellefteå har staden den unika möjligheten att påverkamigrationsmönstren till deras behov och skapa en hållbar och attraktiv stad för den nuvarande ochframtida invånaren. / Today the world stands in front of the challenge of adapting to new demands, where solutions thatincrease sustainability are required. Many cities are therefore undergoing big changes indevelopments where both expected and unexpected consequences will arise. Since 2017, whenNorthvolt decided to establish in Skellefteå, the city stands in front of the opportunity to become apioneer city of green evolution. The new development has not only put the demands of the industryat test, but also the city as whole. The challenge of the municipality is how to spread the message ofwhat the upcoming development has to offer to boost the in-migration, as the need for competence isthe main challenge of Skellefteå today. To be able to fulfil and meet the visions of the transformation,all actors need to work together in becoming the green city of electrification. To create a successfuldevelopment, the overlapping collaboration between the government, industry, academia andcommunity needs to be of high quality and thus the social capital will increase.The thesis explores the effects of a city that undergoes a fast expansion. By studying migrationpatterns through push and pull theory, the thesis investigates how to generate an increasedin-migration in different target groups, such as students and returners. While Skellefteå is dependenton having a positive netto in-migration, the current residents also need to be maintained, thusinterviews and a questionnaire has allowed the thesis to obtain a clear picture of strengths andweaknesses of the development in Skellefteå. The results of the questionnaire and the interviews areanalysed and discussed through an exemplification of the two theories of push and pull and thetheory of social capital.Large industrial expansions of this size shake cities to their core, as the identity and attributes of thecity are questioned as they change. When dealing with a development of this size, the social capital isput to the test and depending on its effectiveness, the outcomes can differ. The city is forced to weighdifferent factors against each other, the benefits of accommodating economic, social andenvironmental factors are measured and prioritised as all are not possible to sustain. As the main goalis to create an increased in-migration to the expanding city, the pull factors available and promotedneed to be questioned; What is Skellefteå in fact offering? The thesis identified six possible groups ofin-migration; counterurbanists, lifestyle migrants, people moving for social ties/the returners, peoplemoving for job opportunities, students and people moving for sustainability reasons. By highlightingone set of pull factors, Skellefteå has the unique opportunity to influence the migration patterns totheir needs and create a sustainable and attractive city for the current and future residents.
443

Factors influencing the migration of teachers from Zimbabwe to South Africa

Weda, Zenzele Lungile 12 1900 (has links)
Zimbabwe is suffering from an acute shortage of teachers mainly as a result of teacher emigration to South Africa and abroad. The southern migration of Zimbabwean teachers has received little research attention which has mainly focused on the migration of medical personnel. The purpose of this study is to uncover the factors that drive the migration of teachers from Zimbabwe to South Africa and to explain how these factors function within a grounded theory approach to teacher migration. To achieve this, a review of literature and an empirical study of a small sample of migrant Zimbabwean teachers resident in South Africa were undertaken. A constructivist grounded theory design was used. A theoretical sampling method generated a sample group of thirteen participants who were all qualified Zimbabwean teachers who had migrated to South Africa and been in the country for between one and five years. Data generation and collection consisted of two phases: in the first phase the participants were asked to write a life history narrative or provide a verbal narrative of their life history focussing on their migration. In the second phase they participated in individual interviews to clarify or expand on issues raised in the first phase. Three stages of coding were used in the analysis of the data, namely initial, intermediate and advanced coding. This led to the generation of a grounded theory on teacher migration. The grounded theory indicated that Zimbabwean teachers see migration as the best way to attain an ideal status. An ideal status is conceived to be the ideal interplay between the work conditions, standard of living and social esteem which teachers believe befits members of their profession. Depending on various criteria, teachers fall into one of the following status categories: further diminished status, diminished status, ideal status or ideal status surpassed. Migration is a drastic and demanding way to improve one’s status and it is adopted by teachers only after other strategies to this end have been exhausted. Weighed against existing theories of migration, the grounded theory contributes to understanding teacher migration and retention through the innovative use of the core category status. / Educational Studies / D. Ed. (Socio-Education)
444

Exploring the attraction of nurses to a managed care organization

Straulino, Patrizia 27 January 2014 (has links)
The main aim of this research study was to explore attraction factors pertaining to the literature and to the occupational context of nursing personnel who have exhibited employment interest in a managed care organisation. A qualitative research approach was adopted in which semi-structured interviews were held to collect rich exploratory data from the purposeful sample of nine applicants with nursing qualifications. Twenty-five themes were identified through interpretive data analysis as being important factors in the pre-interview attraction process. The highest ranking of these were identified to be opportunities for professional and personal growth and the relationship with the managed care client, followed by salary and working hours. This study contributes knowledge to Personnel and Career Psychology in the field of Industrial and Organisational Psychology and is pertinent to organisations recruiting nurses, advising them in the formulation of contextually appropriate attraction strategies that attend to the most notable attraction factors / Industrial & Organisational Psychology / M.Com. (Industrial and Organizational Psychology)
445

移民政策與社會網絡—九0年代以來的捷克中國移民 / Migration policy and social networks - Chinese community in the Czech Republic since 1990

曲北蘭, Tulpikova, Petra Unknown Date (has links)
九0年代初,捷克以及其他東、中歐國家成爲世界移民系統的一部份。當時,捷克的開放移民政策及國家的經濟發展吸引全世界移民的目光,其中也包含了中國大陸移民在内。然而,自1995年開始,爲了準備加入歐盟及申根地區,捷克逐漸將移民政策調整成與歐盟目標一致。因而,捷克的政府推行所謂的限制移民政策。因此,隨著開放移民政策的變遷,捷克對移民的拉力減弱。在限制移民政策的狀況之下,在移民過程中,移民國的社會網絡成爲關鍵的移民因素。本文旨在研究探討捷克移民政策的變遷以及中國移民社會網絡的加強對捷克中國移民人數的影響。 / At the beginning of the 1990’s, the Czech Republic, together with other European post-communist countries became a part of the world migration system. Its liberal migration policy and new business opportunities attracted a lot of migrants from different countries, including mainland China, as well. However, in the mid 1990’s, the Czech Republic initiated an effort leading to the membership in the European Union and Shengen Space. Thus, this central European country adopted a far more strict migration policy which corresponded to the EU’s migration rules. As a result, one of the main pull factor of the Czech Republic, i.e., openess to migrants, disappeared with the enlargement of the EU, and moreover migration process involved many restrictions. In this situation social migration networks undertook the role of the main factor which could enable new migrants access the Czech Republic. This thesis describes and analyzes the influence of changing Czech migration policy and subsequent strengthening of social migration ties on the development of Chinese community in the Czech Republic.
446

Vector tugs actuation modeling for ship maneuvering simulators. / Modelagem da atuação de rebocadores vetoriais para simuladores de manobras marítimas.

Barrera, Rodrigo Domingos 02 May 2019 (has links)
Ship Manoeuvring Simulators have proved to be powerful tools on analyzing the feasibility of new maritime maneuvers and new port constructions. In order to provide a complete immersive and real environment, such simulators must correctly represent the dynamics of the controlled vessel as well as the actuation of the tugboats, which have been extremely used over the last years due to the increasing complexity on the maritime maneuvers. Although few simulators can correctly model the dynamics of the tugboats, they still represent their actuation through the so-called \"vector tug model\". This is usually the case because it is expensive to run several integrated-simulators in real-time and the simulator centers do not have trained tugboat captains available. The vector tugs are usually represented as simplified external forces actuating on a vessel. The simplicity of such models causes a loss of realism during a maritime simulation due to the fact that neither the forces exerted on a towed vessel nor the tugboat\'s actuation position are accurate. In addition, tugboats\' actuation response time is usually not taken into account under the current vector tug models used on Ship Manoeuvring Simulators. The main objective of this work is to provide an innovative approach for vector tug actuation modeling in such a way that the towing force magnitude and actuation positions are accurate either in push or pull operation modes. The author will expand the static equilibrium model for tugboat force prediction presented in Brandner (1995) and Artyszuk (2014) and combine it along with optimization techniques in order to accurately obtain the tugboats\' actuation either working under the direct maneuver (i.e., tugboat uses solely its propeller power in order to exert force on a towed vessel) or working under the indirect maneuver (i.e., tugboats use the environmental disturbances and the hull drag in order to maximize their actuation force on a towed vessel). The implementation of the new mathematical model provides a new level of reality when vector tugs are used in Ship Manoeuvring Simulators. / Simuladores Navais têm provado ser poderosas ferramentas, tanto na análise de viabilidade de novas manobras portuárias, quanto na construção de novos portos. De modo a conseguir criar um ambiente imersivo e realista, tais simuladores devem conseguir representar corretamente a dinâmica de um navio a ser controlado e a atuação dos rebocadores portuários no mesmo. Embora alguns simuladores consigam modelar corretamente a dinâmica de rebocadores portuários, eles ainda representam tal atuação utilizando o modelo comumente chamado de \"rebocadores vetoriais\". Tal fato normalmente acontece pois é muito caro utilizar diversos simuladores conectados em tempo real. Além disso, em muitas ocasiões, os centros de simulação não têm disponível um comandante de rebocador treinado e capaz de manusear o mesmo de forma correta. Os rebocadores vetoriais normalmente são representados com modelos simplificados de forças externas atuantes em um navio a ser rebocado. A simplicidade de tais modelos gera uma grande perda de realismo durante uma simulação marítima dado que tanto as forças exercidas em um navio a ser rebocado quanto as posições de atuação dos rebocadores são imprecisas. Ainda, os tempos de resposta para a atuação dos rebocadores normalmente não é levado em conta nos modelos de rebocadores vetoriais presentes atualmente. O principal objetivo deste trabalho é prover uma abordagem inovadora para a modelagem da atuação de rebocadores vetoriais, de tal modo que a magnitude da sua força de reboque e seu posicionamento, tanto atuando no modo empurrar quanto no modo puxar, sejam fidedignos a realidade. O autor irá expandir o modelo de equilíbrio estático para predição de forças de atuação de rebocadores apresentado tanto em Brandner (1995) quanto em Artyszuk (2014), e irá introduzir técnicas de otimização de modo a obter a configuração precisa de atuação dos rebocadores tanto na manobra de modo direto quanto na manobra de modo indireto. As implementações propostas elevarão o nível de realidade de Simuladores Navais quando rebocadores vetoriais forem empregados.
447

EFEITO DA APLICAÇÃO SÔNICA DE SISTEMAS ADESIVOS NA ADESÃO DE PINOS DE FIBRA DE VIDRO NO CANAL RADICULAR / EFFECTS OF SONIC APPLICATION OF ADHESIVE SYSTEMS ON BONDING FIBER POSTS TO ROOT CANALS

Sánchez, Johanna Lizbeth Cuadros 26 February 2014 (has links)
Made available in DSpace on 2017-07-24T19:22:33Z (GMT). No. of bitstreams: 1 Johanna Lizbeth Cuadros Sanchez.pdf: 3888267 bytes, checksum: abbdebf22c3a3a8b49c91f6bc734b34d (MD5) Previous issue date: 2014-02-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Abstract: Luting of posts inside the root canal is still a challenge because of the difficult to bonding mainly in the apical third. The aim of this study was evaluate the influence of the application of 3 simplified total-etch adhesive systems (Adper Single Bond 2 Ambar, and XP-Bond+self-cure activator) under manual mode or sonic vibration on the push-out bond strength (POBS), silver nitrate uptake (SNU) and in situ degree of conversion (ISDC) associated to resin cement when used for luted posts. Methods: The roots of 66 human premolars were prepared and divided into six groups (n=11), according to the following combination: adhesive and application mode. The posts were cemented in accordance with the manufacturer’s instructions of each cementation system. After water storage, the roots were sectioned transversely into six slabs and it were tested in POBS (0.5mm/min). Two roots for group were data were immersed in 50% silver nitrate, photo-developed and analyzed by SEM to measure the SNU. Two roots for group were evaluated by micro-Raman spectroscopy to measure ISDC. The data were analyzed by 3-way repeated measures ANOVA and Tukey's tests (5%). Results: When sonic application was performed, usually there are a significantly increasing on the POBS (MPa) (35% and 37% respectively) and ISDC (%) (14% and 38% respectively in the medium and apical thirds) and decreasing of SNU (%) for all groups mainly in the medium (64% decreasing) and apical (84%) thirds when compared with manually application (P < 0.05). / Resumo: A cimentação de pinos dentro do canal radicular ainda é um desafio por causa das dificuldades relativas à adesão, principalmente no terço apical. O objetivo deste estudo foi avaliar a influência da aplicação de três sistemas adesivos convencionais simplificados (Adper Single Bond 2, Ambar e XP-Bond + self cure ativator) manualmente ou através de um dispositivo sônico vibratório na resistência de união por push-out (RU), na infiltração de nitrato de prata (NI) e no grau de conversão in situ (GC) associado ao cimento resinoso de cada fabricante, quando utilizado para cimentação de pinos. Métodos: As raízes de 66 pré-molares humanos foram preparadas e divididas em seis grupos (n = 11), de acordo com a seguinte combinação: adesivo/cimento e modo de aplicação. Os pinos foram cimentados de acordo com as instruções do fabricante de cada sistema de cimentação apenas variando o modo de aplicação. Depois do armazenamento em água, as raízes foram seccionadas transversalmente em seis fatias e foram testados em RU (0,5 mm/min). Duas raízes por grupo foram imersas em 50% de nitrato de prata, e após revelação, foram analisadas por MEV para medir a NI. Duas raízes por grupo foram avaliadas por espectroscopia de micro-Raman para medir GC. Os dados foram analisados por análise de variância de 3 fatores de medidas repetidas (terço radicular) e teste de Tukey (5%). Resultados: Quando a aplicação sônica vibratória foi utilizada, em geral, se observou um aumento significativo na RU (MPa) (35% e 37% respectivamente) e GC (%) (14% e 38% respectivamente nos terços médio e apical) e diminuição da NI (%) para todos os grupos, principalmente nos terços médio (redução de 64%) e apicais (84%) quando comparada com a aplicação manual (p <0,05) e este fenômeno ocorreu para todos os sistemas adesivos/cimentos testados.
448

Study of Tied-up Capital Level in Supply Chain in Vehicle Sector

Kiani, Amirkiarash January 2012 (has links)
In vehicle industry, it has been trends towards focusing on pull-basedsystems and elimination of waste (Lean), which decrease the tied-up capitallevel in the focal factory. Research by Holweg &amp; Miemczyk (2002)showed that the relevant supply chain has low inventory level in the focalfactory, but at upstream and especially downstream; the tied-up capitallevel is dramatically higher in comparison to the focal factory.By conducting research and extensive literature reviews, this volatilityof tied-up capital level has been studied and analysed with regard topush and pull systems. As the three main causes of this unevenness; bullwhipeffect, CODP position in supply chain and intensity level of supplierrelationship have been identified and explained.As a practical solution for decreasing the tied-up capital level of finishedvehicles, implementation of centralised warehouse structure hasbeen suggested and discussed.Moreover, as an application of game theory in logistics, iterated prisoners’dilemma has been discussed as the base for a progressive relationshipwith suppliers (upgrading to win-win game) which is requisite for the successof pull-based supply chains. / Program: BSc in Industrial Engineering - International Business Engineering
449

Laser de Er,Cr:YSGG em condutos radiculares preparados para cimentação de núcleos protéicos / The utilization of Er,Cr:YSGG laser in prosthetic post space preparation before post placement

Quinto Junior, José 19 December 2011 (has links)
O objetivo deste estudo é avaliar a influência da irradiação com laser de Er,Cr:YSGG no espaço protético de condutos radiculares preparados para a fixação de pinos em fibra de vidro reforçados (FRC Postec®), avaliando-se o comportamento de três diferentes técnicas adesivas (self-etching= Panavia F®; total-etching= Excite DSC® + Variolink II® e self-adhesive= RelyX Unicem Aplicap®). Observaram-se as orientações da norma ISO-TS 11405 para a preparação das raízes dentais unirradiculares humanas. As amostras foram separadas na altura da junção amelo-dentinaria, tratadas endodonticamente com instrumentação rotatória e seladas com técnica de condensação lateral. Foram utilizados dois tipos diferentes de pontas de safira para irradiação intracanal o axial (Z4, 400 m de diâmetro) e o radial ou side firing (RFT4, 415 m de diâmetro) com densidade de energia de 40 J/cm2. Esta densidade de energia foi obtida como parte deste experimento, analisando-se diversos parâmetros de energia com os resultados morfológicos e térmicos obtidos. Nesta densidade, obtive-se grande quantidade de túbulos dentinários abertos e variação de temperatura segura para uso clínico. Cada raiz foi irradiada em cinco movimentos circulares, de apical para cervical, com intervalo de 20 segundos, entre elas. Os FRC Postec foram cimentados imediatamente após a irradiação e divididos randomicamente em nove grupos (n=10). Cada raiz foi seccionada em 6 discos de 1 mm de espessura para ensaio do tipo push-out, para a obtenção da força máxima de ruptura, e posterior cálculo da resistência de união adesiva em função da área de superfície do núcleo deslocado, resultando na pressão em MPa. A resistência de união adesiva nos grupos irradiados foi estatisticamente superior do que os grupos controle. Foram avaliadas as diferenças na resistência de união adesiva em diferentes porções do núcleo (cervical, médio e apical), onde o sistema adesivo tipo self-adhesive (RelyX Unicem Aplicap) teve o melhor resultado para os grupos irradiados. Avaliou-se por técnica de FTIR as diferenças químicas ocorridas na dentina intrarradicular irradiada com laser de Er,Cr:YSGG, em diferentes porções (cervical, médio e apical) em função da orientação dos túbulos. Foram observadas nos espectros de FTIR alterações na intensidade das bandas de algumas moléculas, indicando variação na quantidade da parte orgânica (amida I e amida II) após a irradiação, nas diferentes regiões dentais em função do feixe laser sobre a orientação dos túbulos dentinários, sem causar alterações na sua composição. Essas diferenças podem interferir no resultado da resistência de união adesiva. A técnica de utilização de laser de Er,Cr: YSGG em dentina radicular pré-cimentação de núcleo protético aumenta a resistência de união adesiva, na dependência do cimento utilizado. / The aim of this study was to evaluate the influence of the Er,Cr:YSGG laser irradiation in the prosthetic post space before FRC Postec placement using three different adhesive systems (self-etching- Panavia F; total-etching- Excite DSC + Variolink II e self adhesive - RelyX Unicem Aplicap). According to ISO-TS 11405, sectioned at the CEJ, human dental single roots were endodontically treated with rotatory instruments and filled with gutta-percha points and sealer. Were used at 40 J/cm2 an axial Z4 laser tip (400 m diameter) and a radial (side firing) RFT4 laser tip (415 m diameter). This density of energy was experimentally determinated observing morphological changes in SEM images due to an increase range in the energy applied to dentinal root canal surface. At the length between 32 and 49 J/cm2 most of the intracanal dentinal tubules were open. The temperature increase was within the biological safe suggesting a feasible clinical use. Each root canal was irradiated five times with helicoidal movements from apical to cervical, with 20 seconds interval. FRC Postec were immediately cemented and randomly divided in nine groups (n=10). Each root canal was cut in six discs for push out test, were the maximum failure load was obtained and the bond strength was calculated as a function of post bonded area. The bond strength for the irradiated groups was superior among all control groups. The evaluation of bond strength among root region (cervical, middle and apical) was performed and differences were observed. The self-adhesive (RelyX Unicem Aplicap) system was noted superior among all irradiated groups and all regions. Chemical changes were analyzed by FTIR due to dental root portion and dentinal tubules orientation to laser beam direction. The FTIR spectra obtained indicated changes due to tubules orientation and root canal portion irradiated such as the proportion among the compositional ratio without causing chemical changes. These compositional ratio alterations may affect the bond strength results. The irradiation with Er,Cr:YSGG laser on dentinal walls of a prosthetic post space preparation before the post cementation, as suggested in this study, may increase the bond strength between the post and root canal dentin depending upon the luting cement that is used.
450

Calidad de vida y cicatrización en pacientes con úlceras de etiología venosa: adaptación transcultural y validación del "Charing cross venous ulcer questionnaire (CCVUQ)" y del "Pressure ulcer scale for healing (PUSH)"

González Consuegra, Renata Virginia 15 April 2011 (has links)
La Ulcera Venosa (UV) es una patología crónica, que afecta aproximadamente a un 1-2% de la población mayor y adulta en los países desarrollados y demanda, importantes costes, en atención a los tratamientos prolongados y variados, inversión de tiempos por parte de profesionales de la salud, consumo de grandes volúmenes de materiales. Se ha constatado que la calidad de vida relacionada con la salud (CVRS) de las personas con UV está afectada negativamente. La medición de CVRS permite, en gran medida, contribuir a mejorar la calidad del cuidado. En España no se dispone de instrumentos de medida específicos CVRS en personas con UV y de medida de la evolución hacia la cicatrización en pacientes con UV, que hayan sido validados mediante la investigación. Disponer de estas herramientas ayudaría a la toma de decisiones y a aumentar la calidad de los cuidados con este tipo de pacientes. / Objetivo General: Determinar CVRS de los pacientes con UV y analizar como la evolución clínica de la herida influye en las distintas dimensiones de la CVRS, mediante la aplicación de instrumentos específicos de medida para tal fin. / Material y Método: El estudio se realizó en tres fases: FASE 1: Revisión bibliográfica y sistemática en las principales bases de datos de ciencias de la salud MEDLINE (a través PubMed y Webspirs), PsycINFO, COCHRANE, CINAHL, LILACS, FECYT, EMBASE y CUIDEN entre 2003 y 2008. Se utilizaron las palabras clave: Leg ulcer, score, quality of life, instrument and tool, con sus correspondientes conectores booleanos. La calidad de las publicaciones fue evaluada mediante CASP Guide (Critical Appraissal Skill Programme y the JBI SUMARI (The Joanna Briggs Institute 2008) herramienta para la evaluación crítica de estudios cualitativos y cuantitativos. / FASE 2: La versión original del cuestionario CCVUQ, que incluye 21 preguntas, se ha adaptado al castellano siguiendo la metodología de traducción y retrotraducción y el establecimiento de equivalencias semánticas culturales. Se efectuaron ajustes considerados menores a partir de los aportes y las sugerencias de expertos y de los pacientes, que no afectó la esencia, de las preguntas originales, pero necesarios para la comprensión de la población local. / FASE 3: estudio de validación, observacional y de medidas repetidas, durante 6 semanas. Se estima una muestra de 105 pacientes. Se calcula consistencia interna mediante alfa de Cronbach, fiabilidad test-retest entre el inicio y la segunda semana, validez concurrente con el SF12.v2 y sensibilidad al cambio mediante ANOVA de medidas repetidas. Para la validez de constructo se realizó un análisis factorial confirmatorio. / Resultados: FASE 1: 22 estudios fueron incluidos, los cuales utilizaron métodos cuantitativos y cualitativos. El dolor se destacó como el hallazgo más prevalerte que afecta la CVRS en los estudios los instrumentos genéricos más utilizados: SF36 y sus adaptaciones, el Nottingham Health Profile y Euroqol-5. En cuanto a los instrumentos específicas de CVRS en UV se encontraron: Hyland, Cardiff Wound Impact Schedule and Charing Cross Venous Leg Ulcer Questionnaire. Dos nuevos instrumentos específicos para UV fueron encontrados Sheffield Preference-Based Venous Leg Ulcer 5D. Se confirma el impacto negativo de las UV en la CVRS, el cual es medido con una variedad de instrumentos específicos, sin embargo por sus valores psicométricos el más adecuado es el Charing Cross Venous Ulcer Questionnaire CCVUQ. / FASE 2: Se obtuvo una versión satisfactoria de la versión española del CCVUQ que es semántica y culturalmente equivalente a la versión original inglesa. En el proceso de adaptación participó un grupo de expertos en heridas crónicas y un grupo de pacientes con úlceras venosas, quienes a partir de los criterios de evaluación de ítems: precisión, claridad y comprensión asignaron resultados de aceptabilidad en el escenario de aplicación del 94% a la totalidad de los ítems como Índice de Validez de Contenido (IVC). / FASE 3: se incluyen 60 pacientes, en su mayoría mujeres (66,7%), con mediana de edad de 78 años. El 75% de las lesiones eran recurrentes con una antigüedad mediana de 2,14 años. La consistencia interna para el CCVUQ-e es alta (alfa>0,80), para el PUSH-e es baja. Ambos instrumentos tienen buena fiabilidad test-retest (CCVUQ-e ICC: 0,71, PUSH-e ICC: 0,97). Se confirma el modelo factorial de 4 dimensiones. Hay buena correlación entre el SF12.v2 y el CCVUQ-e. La sensibilidad al cambio es buena para los dos instrumentos de medida (diferencia de -44,3 puntos para el CCVUQ-e). / Conclusiones: queda confirmada la validez, fiabilidad y sensibilidad al cambio del CCVUQ-e. En el caso del PUSH-e solo se puede confirmar la sensibilidad al cambio a partir de la segunda semana de tratamiento. Además, se confirma que los pacientes con UV tienen mala CVRS cuando esta es medida con el CCVUQ-e y con el SF12 V2 pero que esta mejora cuando mejora el estado de la UV.

Page generated in 0.0482 seconds