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  • 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.
51

The Effect of High Cervical Spinal Cord Stimulation on the Expression of SP, Nk-1 and TRPV1 mRNAs During Cardiac Ischemia in Rat

Ding, Xiao Hui, Mountain, Deidra J.Hopkins, Subramanian, Venkateswaran, Singh, Krishna, Williams, Carole Ann 07 September 2007 (has links)
Spinal cord stimulation (SCS) is used to reduce angina that accompanies cardiac ischemia, but little is known about the molecular mechanisms mediating this effect. We studied the expression of SP, neurokinin-1 (NK-1) receptor, and transient receptor potential vanilloid type 1 (TRPV1) mRNA in the rat spinal cord at thoracic 4 (T4), cervical 2 (C2) and caudal brain stem by RT-PCR during intermittent occlusion of the left anterior descending coronary artery (CoAO), during sustained SCS by itself at the C2 spinal segment, and during sustained SCS plus intermittent CoAO. Only SP mRNA was increased significantly in T4 and brainstem during CoAO, while SCS decreased the mRNA levels of SP, NK-1 and TRPV1 significantly in T4 and the brainstem. SCS attenuated the increase of SP and TRPV1 mRNA levels at T4 level induced by intermittent CoAO when the stimulation was applied prior to the initiation of the cardiac ischemia. These results support the role for SP as a putative neurotransmitter for the myocardial ischemia-sensitive afferent neuron signal to the spinal level. They suggest that modification of the ischemic cardiac nociceptive afferent signal by SCS involves a change in SP and TRPV1 expression.
52

Psigometriese ondersoek na psigologiese optimaliteit

Visser, Chrisna 06 1900 (has links)
Text in Afrikaans / Hierdie ondersoek handel oor die psigometriese verwantskappe tussen verskeie konseptualiserings van psigologiese optimaliteit. Die konsepte selfaktualisering (vanuit 'n humanistiese raamwerk), gevoel van koherensie en aangeleerde vernuftigheid (vanuit 'n behavioristiese en salutogenesis paradigma) is vir die doeleindes van hierdie ondersoek gekies. Die gekose meetinstrumente, naamlik die Persoonlike Orientasievraelys vir selfaktualisering, die Lewensorientasievraelys vir gevoel van koherensie en die Selfkontroleskedule vir aangeleerde vernuftigheid, is op 'n steekproef van 200 middelvlakbestuurders in 'n semi-staatsdiensorganisasie afgeneem. Pearsonkorrelasiekoeffisiente is bereken en 'n faktorontleding is gedoen. Daar is verskeie beduidende korrelasies verkry tussen die subskale van die Persoonlike Orientasievraelys en die Lewensorientasievraelys, maar slegs enkele beduidende korrelasies tussen die Persoonlike Orientasievraelys en die Selfkontroleskedule. Die Lewensorientasievraelys en die Selfkontroleskedule het egter beduidend gekorreleer. Die faktorontleding het getoon dat selfaktualisering aan die een kant, en gevoel van koherensie en aangeleerde vernuftigheid aan die ander kant as twee verskillende konstrukte van psigologiese optimaliteit beskou kan word. / The relationships between various conceptualisations of psychological optimisation are investigated. The concepts of self-actualisation (from a humanistic paradigm), sense of coherence and learned resourcefulness (from a salutogenesis paradigm) are relevant. The measuring instruments were the Personal Orientation Inventory (POl), the Orientation to Life Questionnaire (OLQ) and the Self Control Schedule (SCS). They were administered by means of random sampling of 200 middle level managers in a semi-government organisation. Pearson correlation coefficients were calculated and a factor analysis was done. Several significant correlations were obtained between the subscales of the POl and the OLQ, but limited correlations were found between the POl and the SCS. However, significant correlations between the OLQ and the SCS were apparent. The factor analysis demonstrated that self-actualisation on the one hand and sense of coherence as well as learned resourcefulness on the other hand may be regarded as two seperate constructs of psychological optimisation. / Industrial and Organisational Psychology / Thesis (M.Com.)--Universiteit van Suid Afrika, 1994.
53

Un couplage de modèles hydrologique et hydraulique adapté à la modélisation et à la prévision des crues à cinétique rapide – Application au cas du bassin versant du Gardon (France). / A coupling of hydrologic and hydraulic models appropriate for modelling and forecasting fast floods – Application to the Gardon river basin (France).

Laganier, Olivier 29 August 2014 (has links)
Les bassins versants du pourtour méditerranéen français sont touchés par des pluies parfois intenses et à fort cumuls, qui peuvent engendrer des crues à cinétique rapide. Les derniers exemples majeurs en date sont ceux de l’Aude en 1999, du Gard en 2002 et du Var en 2010, dont les conséquences furent dramatiques. Ces travaux de thèse visent à évaluer une approche de modélisation complémentaire aux outils dont disposent déjà les Services de Prévision des Crues pour la prévision des crues à cinétique rapide : le couplage de modèles hydrologique et hydraulique, qui est a priori adapté pour la modélisation à l’échelle des grands bassins méditerranéens, de superficies supérieures à 1 000 km² (Ardèche, Cèze, Gardon, Vidourle…). Des éléments de réponses aux 4 questions suivantes sont recherchés : 1) le couplage est-il adapté pour la modélisation des débits atteints lors d’évènements passés, d’importance intermédiaire ? 2) le couplage est-il performant pour la modélisation des débits, cotes atteintes, et extension d’inondation, observés lors d’un épisode majeur? 3) comment envisager d’améliorer la modélisation des apports latéraux non-jaugés au modèle hydraulique, tout en adoptant une démarche adaptée à la prévision ? 4) le couplage est-il performant en prévision ? Le couplage employé combine le modèle hydrologique SCS-LR de la plateforme ATHYS (Bouvier et al., 2004), et le code de modélisation hydraulique 1D MASCARET (EDF-CETMEF, 2011). Il est appliqué au bassin versant du Gardon (2 040 km²), dans le sud de la France. / The French catchments around the Mediterranean Sea are affected by intense rains, which can cause fast and flash floods. The last major events are the one of the Aude river in 1999, of the Gard area in 2002, and of the Var area in 2010, whose consequences were tragic. This PhD intends to assess a modeling strategy complementary to the tools that are already used by the regional flood warning services: the coupling of hydrologic and hydraulic models, which is a priori well-adapted for the modelling of catchments of large-scale areas (larger than 1 000 km²) around the Mediterranean Sea (such as the ones of the Ardèche river, the Cèze river, the Vidourle river, the Gardon river…). The works aim at bringing elements of responses to the following questions: 1) is the coupling adapted to the modelling of floods hydrographs of past events of moderate importance? 2) in case of an extreme event (like in September 2002), is the coupling effective for the modelling of discharges, of water levels, and of flood extension? 3) how can we improve the modelling of ungauged lateral inflows to the hydraulic model, while applying a method adapted to forecasting? 4) Is the coupling efficient at forecasting? The coupling used combines the SCS-LR hydrologic model of the ATHYS platform (Bouvier et al., 2004), and the MASCARET 1D hydraulic model (EDF-CETMEF, 2011). It is applied to the Gardon river basin (2 040 km²), in the South of France.
54

A supervisão de estágio na formação profissional do assistente social: uma análise na Faculdade Paulista de Serviço Social de São Caetano do Sul / The apprenticeship s supervision in the professional formation of social works: an analysis in the College Paulista of Social Work at São Caetano do Sul

Nascimento, Juciléia Aparecida 05 October 2007 (has links)
Made available in DSpace on 2016-04-29T14:17:10Z (GMT). No. of bitstreams: 1 Jucileia Aparecida Nascimento.pdf: 743473 bytes, checksum: d2d2462dc8b9e0b606c11430597ef233 (MD5) Previous issue date: 2007-10-05 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / This present study analyzed the process of the apprenticeship s supervision during the professional formation of social works in the College Paulista of Social Work at São Caetano do Sul (FAPSS/SCS), since the implantation of the current curriculum according to the curricular lines indicated by ABEPSS (Brazilian Association of Teaching and Research in Social Work) in the year of 1996. Our research, which has a quality character, involved a documental study of archives and materials of the proper College, such as the conceptions about supervision and apprenticeship; about them, we built a dossier trying to capture different ways to think the issue, in the scope of the thoughts of some authors who had treated this question in the Social Work. As our research s main subjects, we established them as the supervisors of FAPSS/SCS, and with them we had developed the focal group, instrument that allowed us to get more knowledge about the practice of supervision and the possible changes that happened in the apprenticeship s field after the new curriculum. We also had done interviews half structuralized with the representatives of the Department of Apprenticeship to learn about the supervision in the professional formation before and during the implantation of the current curriculum. The most substantive change pointed by the supervisors and which was observed in the FAPSS/SCS, it was the introduction of the monthly workshops, that, although those workshops were indicated as important, they are not enough to reach a bigger approach between the College and the apprenticeship s field, because of the limitations e contradictions in the daily dynamics of the institutions where happens the training period. Another aspect that it is not treated in the curriculum, even though it has been emphasized by the supervisors, it is the need of preparation in the moment of graduation to the exercise of the supervision. Still today, there are many issues that keep worrying the professionals in the moment of the apprenticeship s supervision, indicating the needs to also make it priority in the professional formation of social works, always having in mind the articulation between all the subjects involved in this process / O presente estudo tem como objetivo analisar o processo de supervisão de estágio na formação profissional do assistente social na Faculdade Paulista de Serviço Social de São Caetano do Sul (FAPSS/SCS), a partir da implantação do atual currículo pautado nas diretrizes curriculares propostas pela ABEPSS (Associação Brasileira de Ensino e Pesquisa em Serviço Social) no ano de 1996. Nossa pesquisa, de caráter qualitativo, envolveu um estudo documental, tanto dos arquivos e materiais da própria Faculdade, como das concepções sobre supervisão e estágio; sobre elas, construímos um dossier tentando capturar os diferentes modos de pensar a questão, no âmbito do pensamento de alguns autores que trataram o assunto no Serviço Social. Como sujeitos principais da pesquisa estabelecemos os supervisores da FAPSS/SCS, e com eles desenvolvemos o grupo focal, instrumento que favoreceu a obtenção de maiores conhecimentos sobre a prática da supervisão e as possíveis mudanças que ocorreram no campo de estágio após o novo currículo. Realizamos também, entrevistas semi-estruturadas com as representantes do Departamento de Estágio para apreendermos a supervisão na formação profissional antes e durante a implantação do atual currículo. A mudança substantiva apontada pelas supervisoras e observada na FAPSS/SCS foi a introdução das oficinas mensais, que, embora indicadas como importantes, não são suficientes para imprimir maior aproximação entre Faculdade e campo de estágio devido as limitações e contradições presentes na dinâmica cotidiana das instituições campos de estágio. Outro aspecto que não é tratado no currículo, mas bastante enfatizado pelas supervisoras é a necessidade da preparação formativa para o exercício da supervisão. Ainda hoje são muitas as inquietações que permeiam o exercício da supervisão de estágio, indicando a necessidade de torná-la também prioridade na formação profissional do assistente social, a partir da articulação entre todos os sujeitos envolvidos nesse processo
55

Modelagem hidrológica da bacia hidrográfica do rio Bengalas, Nova Friburgo, RJ, utilizando o potencial de geotecnologias na definição de áreas de risco de inundação.

Evaldo Flávio Gomes Correia 11 October 2011 (has links)
A presente pesquisa concentra-se no estudo hidrológico utilizando o potencial das geotecnologias na modelagem do escoamento na bacia do rio Bengalas, cujo rio principal de mesmo nome, corta o município de Nova Friburgo, RJ, no sentido Sul-Norte. Esse município, um dos mais importantes da região serrana, sofre frequentemente com inundações e deslizamentos, onde, dados históricos e acontecimentos recentes mostram que a ocupação inadequada de encostas e calhas dos rios são as áreas destacada e negativamente afetadas. A metodologia tem suporte no uso de um SIG, extraindo informações, que por sua vez, serão entrada de dados na fase de modelagem, e reforçando a apresentação dos resultados das simulações através de mapas. Ela está divida basicamente em três etapas: "SIG", "Modelagem" e "Suporte à Tomada de Decisão/Simulação". Esse primeiro estudo permitiu compor um banco de dados geográfico com as características fisiográficas da bacia; a seleção criteriosa de uma modelagem matemática e encadeamento de seus parâmetros com os componentes do ciclo hidrológico; realizar a calibração do modelo de transformação chuva-vazão, Soil Conservation Service (CN); e simular a passagem dos volumes gerados pela precipitação efetiva na calha do rio Bengalas, com o objetivo de identificar e analisar as áreas suscetíveis a inundações na porção central da cidade de Nova Friburgo. Modelagem dessa natureza vem sendo empregada, principalmente, no gerenciamento de recursos hídricos, onde a tomada de decisões embasada nos resultados de simulações computacionais, contribuem para evitar prejuízos materiais e financeiros, e ainda, perdas de vidas humanas em áreas de risco, neste caso, aquelas suscetíveis a inundações. Analisando os resultados encontrados temos que a área suscetível à inundação para uma chuva com tempo de recorrência de 50 anos, o mais crítico estudado, seja de aproximadamente 1,0 km, distribuídos nos seus 8,5km na região central de Nova Friburgo-RJ, sendo está, ora delimitada, prioritariamente edificada. / This research focuses on the hydrological study using the potential of geotechnology into runoff modeling of the Bengalas Basin, whose main river, with same name, crosses the city of Nova Friburgo - RJ, in a south-north orientation. This city, one of the most important in "Região Serrana", suffers often with floods and landslides, which, historical data and recent events show that the inappropriate occupation of hillsides and margins of rivers are the highlighted and negatively affected areas. The methodology has basis in a GIS application, extracting information, which in turn, are input in the modeling phase, and enhancing the presentation of simulation results through maps. It is basically divided into three stages: "SIG", "Modelagem" and "Suporte à Tomada de Decisão/Simulação." This first study allowed to compose a geographic database with the physiographic features of the basin; the careful selection of a chain of mathematical modeling and its parameters with the hydrological cycle components, perform the calibration of the rainfall-runoff transformation model, Soil Conservation Service (CN) and simulate the transition of volumes generated by an effective precipitation in the Bengalas river, in order to identify and analyze the susceptible flooding areas in the central part of Nova Friburgo. A kind of this modeling has been used, mainly, in the water resource management, in which decision-making are based on results of computer simulations, helps to avoid a range of losses, such as material, financial and, especially, humans, that in this case, people who lives in areas susceptible to flooding. Analyzing the results, it was found that an area susceptible to flooding by a rainfall with a recurrence time of 50 years, the most critical studied, results in approximately 1.0 km, distributed in its 8.5km (central part of Nova Friburgo - RJ) which this bounded area has a great part with buildings.
56

Psigometriese ondersoek na psigologiese optimaliteit

Visser, Chrisna 06 1900 (has links)
Text in Afrikaans / Hierdie ondersoek handel oor die psigometriese verwantskappe tussen verskeie konseptualiserings van psigologiese optimaliteit. Die konsepte selfaktualisering (vanuit 'n humanistiese raamwerk), gevoel van koherensie en aangeleerde vernuftigheid (vanuit 'n behavioristiese en salutogenesis paradigma) is vir die doeleindes van hierdie ondersoek gekies. Die gekose meetinstrumente, naamlik die Persoonlike Orientasievraelys vir selfaktualisering, die Lewensorientasievraelys vir gevoel van koherensie en die Selfkontroleskedule vir aangeleerde vernuftigheid, is op 'n steekproef van 200 middelvlakbestuurders in 'n semi-staatsdiensorganisasie afgeneem. Pearsonkorrelasiekoeffisiente is bereken en 'n faktorontleding is gedoen. Daar is verskeie beduidende korrelasies verkry tussen die subskale van die Persoonlike Orientasievraelys en die Lewensorientasievraelys, maar slegs enkele beduidende korrelasies tussen die Persoonlike Orientasievraelys en die Selfkontroleskedule. Die Lewensorientasievraelys en die Selfkontroleskedule het egter beduidend gekorreleer. Die faktorontleding het getoon dat selfaktualisering aan die een kant, en gevoel van koherensie en aangeleerde vernuftigheid aan die ander kant as twee verskillende konstrukte van psigologiese optimaliteit beskou kan word. / The relationships between various conceptualisations of psychological optimisation are investigated. The concepts of self-actualisation (from a humanistic paradigm), sense of coherence and learned resourcefulness (from a salutogenesis paradigm) are relevant. The measuring instruments were the Personal Orientation Inventory (POl), the Orientation to Life Questionnaire (OLQ) and the Self Control Schedule (SCS). They were administered by means of random sampling of 200 middle level managers in a semi-government organisation. Pearson correlation coefficients were calculated and a factor analysis was done. Several significant correlations were obtained between the subscales of the POl and the OLQ, but limited correlations were found between the POl and the SCS. However, significant correlations between the OLQ and the SCS were apparent. The factor analysis demonstrated that self-actualisation on the one hand and sense of coherence as well as learned resourcefulness on the other hand may be regarded as two seperate constructs of psychological optimisation. / Industrial and Organisational Psychology / Thesis (M.Com.)--Universiteit van Suid Afrika, 1994.
57

Modelagem hidrológica da bacia hidrográfica do rio Bengalas, Nova Friburgo, RJ, utilizando o potencial de geotecnologias na definição de áreas de risco de inundação.

Evaldo Flávio Gomes Correia 11 October 2011 (has links)
A presente pesquisa concentra-se no estudo hidrológico utilizando o potencial das geotecnologias na modelagem do escoamento na bacia do rio Bengalas, cujo rio principal de mesmo nome, corta o município de Nova Friburgo, RJ, no sentido Sul-Norte. Esse município, um dos mais importantes da região serrana, sofre frequentemente com inundações e deslizamentos, onde, dados históricos e acontecimentos recentes mostram que a ocupação inadequada de encostas e calhas dos rios são as áreas destacada e negativamente afetadas. A metodologia tem suporte no uso de um SIG, extraindo informações, que por sua vez, serão entrada de dados na fase de modelagem, e reforçando a apresentação dos resultados das simulações através de mapas. Ela está divida basicamente em três etapas: "SIG", "Modelagem" e "Suporte à Tomada de Decisão/Simulação". Esse primeiro estudo permitiu compor um banco de dados geográfico com as características fisiográficas da bacia; a seleção criteriosa de uma modelagem matemática e encadeamento de seus parâmetros com os componentes do ciclo hidrológico; realizar a calibração do modelo de transformação chuva-vazão, Soil Conservation Service (CN); e simular a passagem dos volumes gerados pela precipitação efetiva na calha do rio Bengalas, com o objetivo de identificar e analisar as áreas suscetíveis a inundações na porção central da cidade de Nova Friburgo. Modelagem dessa natureza vem sendo empregada, principalmente, no gerenciamento de recursos hídricos, onde a tomada de decisões embasada nos resultados de simulações computacionais, contribuem para evitar prejuízos materiais e financeiros, e ainda, perdas de vidas humanas em áreas de risco, neste caso, aquelas suscetíveis a inundações. Analisando os resultados encontrados temos que a área suscetível à inundação para uma chuva com tempo de recorrência de 50 anos, o mais crítico estudado, seja de aproximadamente 1,0 km, distribuídos nos seus 8,5km na região central de Nova Friburgo-RJ, sendo está, ora delimitada, prioritariamente edificada. / This research focuses on the hydrological study using the potential of geotechnology into runoff modeling of the Bengalas Basin, whose main river, with same name, crosses the city of Nova Friburgo - RJ, in a south-north orientation. This city, one of the most important in "Região Serrana", suffers often with floods and landslides, which, historical data and recent events show that the inappropriate occupation of hillsides and margins of rivers are the highlighted and negatively affected areas. The methodology has basis in a GIS application, extracting information, which in turn, are input in the modeling phase, and enhancing the presentation of simulation results through maps. It is basically divided into three stages: "SIG", "Modelagem" and "Suporte à Tomada de Decisão/Simulação." This first study allowed to compose a geographic database with the physiographic features of the basin; the careful selection of a chain of mathematical modeling and its parameters with the hydrological cycle components, perform the calibration of the rainfall-runoff transformation model, Soil Conservation Service (CN) and simulate the transition of volumes generated by an effective precipitation in the Bengalas river, in order to identify and analyze the susceptible flooding areas in the central part of Nova Friburgo. A kind of this modeling has been used, mainly, in the water resource management, in which decision-making are based on results of computer simulations, helps to avoid a range of losses, such as material, financial and, especially, humans, that in this case, people who lives in areas susceptible to flooding. Analyzing the results, it was found that an area susceptible to flooding by a rainfall with a recurrence time of 50 years, the most critical studied, results in approximately 1.0 km, distributed in its 8.5km (central part of Nova Friburgo - RJ) which this bounded area has a great part with buildings.
58

En kvantitativ undersökning av hur iKBT påverkar samvetsstress och arbetsrelaterad stress hos vårdpersonal under hård arbetsbelastning till följd av Covid-19 / A Quantitative Analysis of the Effects of iCBT on Stress of Conscience and Work-Related Stress Among Healthcare Staff under High Workload due to Covid-19

Dahlberg, Patrik, Nikoo, Sara January 2021 (has links)
Antalet sjukskrivningar till följd av stressrelaterade sjukdomar har ökat kraftigt för vårdpersonal. Därtill saknas det evidens för internetbaserade interventioner mot stressrelaterad ohälsa för vårdpersonal. Syftet var att undersöka och utvärdera en internetbaserad kognitiv beteendeterapi-intervention (iKBT) avseende graden av samvetsstress, arbetsrelaterad stress samt självmedkänsla hos vårdpersonal. Enkäter bestående av Stress of Conscience Questionnaire (SCQ), Copenhagen Psychosocial Questionnaire version II (COPSOQ II) och Self-Compassion Scale (SCS) besvarades av deltagarna (N = 8), samtliga var kvinnor mellan 27 – 53 år. Resultaten analyserades med PEM och RCI på individnivå och T-test på gruppnivå. RCI-analysen visade begränsade resultat för SCQ, blandade resultat för COPSOQ II och övervägande positiva resultat för SCS. Analysen på gruppnivå visade en signifikant minskning i Sömnbesvär (p = .032) och Self-Judgment (p = .021) samt signifikant ökning i Self-Kindness (p = .016). Studien behöver replikeras i framtida studier med ett större antal deltagare och en studiedesign som är metodologiskt robust. / The amount of sick leave due to stress-related illnesses has increased significantly for healthcare staff. In addition, there is a lack of evidence for internet-based interventions for stress-related illness for healthcare staff. The aim was to examine and evaluate an internet-based Cognitive Behavioral Therapy (iCBT) intervention regarding the degree of stress of conscience, work-related stress and self-compassion among healthcare staff. Questionnaires consisting of Stress of Conscience Questionnaire (SCQ), Copenhagen Psychosocial Questionnaire version II (COPSOQ II) and Self-Compassion Scale (SCS) were answered by the participants (N = 8), all were women between 27 - 53 years. The results were analyzed with PEM and RCI at the individual level and T-tests at group level. The RCI analysis showed limited results for SCQ, mixed results for COPSOQ II and predominantly positive results for SCS. The analysis at group level showed a significant decrease in Sleep Disorders (p = .032) and Self-Judgment (p = .021) as well as a significant increase in Self-Kindness (p = .016). The study needs to be replicated in future studies with a larger number of participants and a study design that is more methodologically robust.
59

Characterization of Landscape Structures and Precipitation in relation to Flooding events in Pampa Deprimida : A Minor Field Study in Argentina

Svärd, Linnea January 2023 (has links)
The purpose of the thesis is to characterize flood events within the agricultural fields of flooding Pampa in Argentina. The characterization divides the flat landscape into flood prone areas and endeavour at linking driving factors to flood response based on past events. The characterization is based on information freely available from remote sensing (satelliteimages, digital elevation, and estimated rain data), from precipitation data from a weatherstation and from field measurements carried out with Universidad Nacional de La Plata. The main research question is: Which are the driving factors contributing to the flooding? Data from remote sensing was used to visualize previous areal water extents, to calculate the topographic wetness index, the upslope areas for the field study sites and for a precipitationtrend analysis. Furthermore, data from remote sensing was used to replace missing days of rain data from the weather station. The complemented rain data was compared with the water extent for the events. Relationships between event precipitation, previous precipitation, land-use, and surface runoff was evaluated with the Soil Conservation-Curve Number method, SCS-CN, and the runoff coefficients for different antecedent conditions were calculated. The precipitation data and the satellite images showing water extents were also used to calculatethe 100-year and 20-year storm- and flood event. The measured infiltration capacity was used as input data in the SCS-CN-method to calculate the surface runoff and the measured soilmoisture was used to verify results from the Topographic Wetness Index, TWI, map. The flood risk areas are visualized with satellite images and the calculated Modified Normalized Difference Water Index. The TWI also visualizes the more flood prone or wetter areas and delineates the lower depressions where soil moisture was also measured to be higher, however not significantly. With the available satellite images within the study results indicate that floods are more common wintertime and that great flood events cannot be foreseen with only antecedent precipitation and event precipitation with the SCS-CN method. However, the events in the study with larger water extents, had high precipitation. No clear correlation between water extents from satellite images calculated by Instituto Nacional de Tecnología Agropecuaria, and estimated surface runoff from the SCS-CN method could be seen. However, the obtained runoff coefficients from the SCS-CN method can be used for estimating surface runoff for future storm events were higher Antecedent Moisture Condition, AMC, and low infiltration capacities increases surface runoff. The infiltration capacity of the studied fields is approximately 16 mm/hour and hence not alone a driving factor causing inundation since the soil can absorb, for example, a 20-year storm event of 125 mm/day. However, that is not the case since a 20-year storm flood has covered 9 % of the area around Don Joaquin and El Amanecer with water. No seasonal precipitation trends can be seen in Punta Indio during the last 40 years analysing precipitation data from remote sensing. In flooding Pampa the agricultural fields inundate almost on yearly basis in the depressionsdue to the gentle slopes and high intense precipitation (yearly maximum daily precipitation is always higher than 60 mm/day). To decrease the flood risk the management should ensure high vegetative cover which increases infiltration and balances the hydrological responses. / Syftet med studien är att karakterisera översvämningar inom jordbruket på Argentinska Pampas. Det platta landskapet mest översvämningsutsatta områden pekas ut och arbetet har fokuserat på att koppla landskapets utformning och regnmönster till översvämningarna. Karakteriseringen utgår ifrån information från satellitbilder och digitala höjddata, från nederbördsdata från den närmaste väderstationen som kompletterats med regndata från fjärranlyser och från fältmätningar utförda tillsammans med Universidad Nacional de La Plata. Den huvudsakliga frågan är: Vilka är de bidragande faktorerna till översvämningarna? Information från fjärranalyser användes för att visualisera tidigare översvämningar, för att beräkna det topografiska fuktighetsindexet, tillrinningsområdet för fältstudieplatserna och för en nederbördstrendanalys. Regndatan jämfördes med vattenarean under tidigare översvämningar. Sambanden mellan nederbörd, markanvändning och ytavrinning utvärderades med Soil Conservation-Curve Number metoden, SCS-CN, och avrinningskoefficienterna för olika nederbördsförhållanden beräknades. Nederbördsdata och satellitbilder som visar vattnets utbredning användes också för att beräkna magnituden av ett 100-årsregn och 20-årsregn samt utbredningen av en 100-årsöversvämning. Den i fält uppmätta infiltrationskapaciteten användes som indata i SCS-CN-metoden för att beräkna ytavrinning och den i fält uppmätta markfuktigheten för att verifiera resultat från GISanalysen av det topografiska fuktighetsindexet.' Översvämningsriskområden visualiserades i studien med satellitbilder och det modifierade normaliserade differens vattenindexet. Även det topografiska fuktighetsindexet visualiserar de mer översvämningsbenägna områdena och markerar vattnets väg där markfuktigheten också uppmättes vara högre, dock inte signifikant blötare än ovan liggande punkter. Analys av de tillgängliga satellitbilderna i studien visar att översvämningar är vanligare vintertid och att stora översvämningshändelser inte kan förutses enbart med de senaste dagarnas regnmängd och eventregnet med SCS-CN-metoden. Alla satellitbilder i studien med större vattentäckning kunde dock kopplas till stora regnmängder. Ingen tydlig korrelation mellan vattenutbredningen och uppskattad ytavrinning med SCS-CN-metoden kunde ses. De erhållna avrinningskoefficienterna från SCS-CN-metoden kan dock användas för att uppskatta risken för ytavrinning vid framtida regn där större regnmängder och låg infiltration ökar ytavrinningen. Fältens infiltrationskapacitet är cirka 16 mm/timme och därmed inte ensamt en drivande faktor till översvämningarna eftersom infiltrationskapaciteten är högre än exempelvis ett 20-årsregn (125 mm/dygn). Dock kan 20-årsregn täcka 9 % av området runt Don Joaquin och El Amanecer med vatten. Inga nederbördstrender kan ses i Punta Indio under de senaste 40 åren genom analys av nederbördsdata från fjärranalyser. I Pampa deprimida översvämmar jordbruksfälten nästan årligen i sänkorna på grund av den platta topografin och den höga intensiva nederbörden (den årliga maximala dagliga nederbörden är nästan alltid högre än 60 mm/dag). För att minska översvämningsriskerna bör lantbrukare säkerställa en hög vegetativ täckning som ökar infiltrationen, skyddar marken och balanserar de hydrologiska reaktionerna. / El propósito de la tesis es analizar los posibles eventos de inundación en un sector de la Pampa Deprimida en Argentina, dada la importancia productiva de la región. Se trabajó en los campos de la Universidad Nacional de La Plata con la dirección del curso de Edafología, de la Facultad de Ciencias Agrarias y Forestales. Se caracterizó la región en general y los campos en particular, utilizando información de acceso gratuito en la web, tales como imágenes satelitales, mapas de elevación digital e información meterologíca. Se utilizaron técnicas geomáticas para definir la evolución de agua en superficie mediante un análisis de la precipitación y coberturas de agua en imágenes satelitales obtenidas entre el 2000 y 2022 con la finalidad de calcular el Indice de Humedad Topográfico (TWI). Se establecen relaciones entre la precipitación, el manejo de los campos, la escorrentía superficial y las cuberturas de aguas. Se analizó la occurrencias de eventos de excesos hídricos. Se efectuaron ensayos de infiltración y el método Soil Conservation Service-Curve Number (SCS-CN) a fin de estimar la escorrentía superficial y las medidas de la humedad del suelo para verificar los resultados del mapa con el TWI. Las imágenes satélitales y el Modified Normalized Differential Water Index (MNDWI) calculado, permiten estimar las áreas más expuestas a inundaciones. El TWI permitió distinguir los sectores más altos y bajos mediante la medición de la humedad del suelo. Con los datos disponibles en este estudio, los resultados indican que las inundaciones son más frecuentes en invierno, y que los grandes eventos de inundación no se pueden predecir solo con registros de precipitación y el uso del método SCS-CN. No se pudo observar una correlación entre las extensiones de agua de las imágenes satelitales calculadas por Instituto Nacional de Tecnología Agropecuaria (INTA Clima y Agua, Castelar), y la escorrentía superficial estimada por el método SCS-CN. Sin embargo es possible encontrar una correspondencia entre las precipitaciones muy elevadas y la cobertura de agua. La occurencia de altas precipitaciones luego de un periodo lluvioso en un suelo con baja infiltración debido a una baja cobertura vegetal, aumenta la escorrentía superficial. La capacidad de infiltración del campo estudiado es de aproximadamente 16 mm/hora y un evento de lluvia extrema que se produce cada 20 años puede ser de 125 mm/día. Consecuentemente, no sería la baja infiltración la principal causa de la inundacion. No obstante, se aprecia que effectivamente un evento de 125 mm/día cubre 9 % del área en Don Joaquín y del El Amanecer. Con precipitaciones normales la cobertura es de aproximadamente 2 %. Cabe indicar que las precipitaciones registradas en la estación de Punta Indio durante los últimos 40 años, no manifiestan un comportamiento diferente en su occurencia y cantidad. En Pampa deprimida los campos se inundan frecuente, no solo debido a las precipitaciones locales y el amabiente de muy bajas pendientes. Los flujos de agua subterranea, aunque no se las pudo analizar en este estudio, también afuectuan las coberturas de agua. A fin de disminuirlos riesgos de inundación, el manejo debe garantizar una alta cobertura vegetal que aumente la infiltración y proteja al suelo y, de este modo, contribuir a controlar la natural dinámica hidrológica de la región en estudio. / Estudio del suelo, agua subterránea y vegetación, como base para definir ambientes de manejo en el partido de Magdalena
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Compréhension et amélioration des conditions de couplage par enduction à grande vitesse entre filaments SiCcvd et alliage base titane

Duda, Carine 15 October 2004 (has links) (PDF)
La mise ne oeuvre par voie liquide de matériaux composites à matrice d'alliage de titane renforcés par des filaments de carbure de silicium conduit, malgré la rapidité du procédé utilisé pour enduire les filaments par l'alliage liquide, à d'importantes interactions physico-chimiques au niveau des interfaces formées.<br />Ces interactions entre le revêtement de carbone des filaments et le titane liquide contrôlent en particulier la cinétique de mouillage du filament et les transferts de carbone du filament vers la matrice.<br />Des modèles, confirmés par des observations et analyses microscopiques, ont permis de comprendre les mécanismes mis en jeu au cours du procédé d'élaboration et en particulier de la solidifications. <br />Il est apparu que le dépôt par voie chimique réactive de carbure de titane sur le revêtement de carbone du filament de carbure de silicium était un moyen efficace pour favoriser le mouillage du filament par l'alliage de titane liquide et pour contrôler non seulement les transferts de carbone mais aussi les conditions d'obtention de composites filamentaires correspondant aux spécifications attendues.

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