Dissertations / Theses: 'Poor soil'

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Rwehumbiza, Filbert. "The effect of seed and soil physical conditions on establishment of sorghum." Thesis, University of Aberdeen, 1994. http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU538899.

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The studies reported here, used sorghum to: (i) investigate the effect of changes in the matric suction (m) of filter-paper on germination and water uptake (ii) assess the effect of seed vigour on seedling response to the m of filter paper and to soil mechanical impedance, (iii) investigate the effect of root-shoot interaction on establishment of seedlings subjected to mechanical impedance (MI), and (iv) evaluate the effects of different amounts of planting rain on crop establishment. A technique for controlling matric suction on seed test paper is described and used to study seed germination at m of 0.1, 1 and 10 kPa. Time to 50% germination was increased, and final lengths of both radicles and cleoptiles reduced by an increase in m from either 0.1 to 1, or 1 to 10 kPa. A link between filter paper m, seed-liquid contact area, seed size, the rate of water uptake and germination is discussed. Unimpeded, pregerminated low vigour and fresh seeds produced a similar root and shoot length, fresh mass, and number of leaves and lateral roots. When grown in compacted soil, low vigour seed took longer to emerge but only when seeds were severely aged. (i) Impedance to the shoot delayed emergence, more so when the root was also impeded. (ii) Shoots emerging through a mechanically impeding layer, had greater extension rates after emergence than unimpeded ones. (iii) Mesocotyls became thicker only when the root systems were impeded. (iv) Impeding the shoot system, increased root extension rate. (v) The length of the first internode, the number of leaves and the spacing of lateral roots were not changed by any of the treatments. Germination was >95% in sand columns watered with 5, 10 or 15 mm equivalents of rain. However, seedling emergence was <15% in the 5 mm compared to 77-100% in the 10 and 15 mm treatments. At harvest (9 DAP), all seedlings in the 5 mm treatment were dead. Seedlings given 10 mm rain showed signs of water stress. The interaction between seed vigour, the amount of water available to germinating seed, and soil mechanical impedance and their effect on crop establishment is discussed.

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Saidin, Fadzilah. "Behavior of geosynthetic reinforced soil walls with poor quality backfills on yielding foundations /." Thesis, Connect to this title online; UW restricted, 2007. http://hdl.handle.net/1773/10124.

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Donaldson, Jason. "Are forests restricted by nutrient poor soils? : an analysis of soil nutrient stocks and associated vegetation in the fynbos biome, South Africa." Bachelor's thesis, University of Cape Town, 2011. http://hdl.handle.net/11427/26584.

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The realized woody biomass of the Fynbos Biome in the Western Cape, South Africa falls below the climatic potential to support woody biomass. The lack of substantial tracts of woody forests has long puzzled ecologists, although patchy nutrient distribution and fire disturbance are thought to play a role. The issue has been confounded in the recent past by the invasion of non-indigenous woody plants into formerly low stature fynbos dominated areas. Despite low wood nutrient concentrations, a substantial proportion of nutrients are locked up in the wood of forests due to the large volume of wood. Nevertheless, nutrient stock analysis indicated that plant available nutrients in the poorest global soils (including fynbos soils) are sufficient to support forests (indigenous and alien). I hypothesized that soil nutrient stocks of the Fynbos Biome are sufficient in quantity to support closed canopy indigenous forests with a woody biomass greater than 225 000 kg ha⁻¹ and that alien Pinus spp. and Eucalyptus spp. have lower nutrient stocks than indigenous fynbos species. The study was conducted in the Orange Kloof Forest Reserve and Jonkershoek Nature Reserve within the Western Cape (South Africa). Soil, wood and leaf samples of representative species were collected from indigenous forest, fynbos, E. globulus and P. halepensis and assessed for nutrient contents. Estimates of potential woody biomass on four different soils indicated that indigenous forests would be limited by fynbos soil stocks to below the 225 000 kg ha⁻¹. Pine forest had lower wood nutrient concentrations (mg kg⁻¹, n=6) for N (2466), K (2433), Ca (383), and Fe (34) than indigenous forest species (n=11) N (3427), K (4254), Ca (1636) and Fe (140). The low nutrient stocks in pine wood may allow them to grow tall and be competitive in the shrubby fynbos biome where indigenous forests are limited by expensive wood costs.

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CAMELIN, ENRICO. "Waste meets poor soils: perspectives on sewage sludge recycling." Doctoral thesis, Politecnico di Torino, 2020. http://hdl.handle.net/11583/2842501.

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Turkoglu, Melih. "Two-dimensional Numerical Analysis Of Tunnel Collapse Driven In Poor Ground Conditions." Master's thesis, METU, 2013. http://etd.lib.metu.edu.tr/upload/12615456/index.pdf.

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Insufficient information on the host medium can cause serious problems, even collapse, during construction in a tunnel. This study focuses on understanding the reasons behind the collapse of the Tunnel BT24 to be opened within the framework of Ankara-Istanbul High Speed Railway Project. The tunnel is located near Bozü
yü
k in the Bilecik Province. The collapsed section of the tunnel was driven into a highly weathered, weak to medium rock mass. Unanticipated geological/geotechnical circumstances caused excessive deformations at the section on which the primary support system was applied, leading eventually to collapse. To understand the response of the tunnel and the collapse mechanism, the construction sequence is simulated using two-dimensional plane-strain and axisymmetric finite element models. The analyses were carried out for the section with and without invert closure of the shotcrete liner. To implement the effects of likely unfavorable ground conditions on the tunnel response, a number of fault scenarios and possible creep effects were also considered with those two alternatives. Displacements in the tunnel periphery, forces and moments in the primary liner as well as the plastic deformation zones in the surrounding ground were determined for each case and comprasions were made accordingly. It is concluded that the unforseen ground circumstances might have substantially aggravated the deformations in the section and that the lack of ring closure of the primary liner at invert played the key role in the collapse.

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Osorio, Leyton Javier Mauricio. "Assessment of SWAT to Enable Development of Watershed Management Plans for Agricultural Dominated Systems under Data-Poor Conditions." Diss., Virginia Tech, 2012. http://hdl.handle.net/10919/27747.

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Modeling is an important tool in watershed management. In much of the world, data needed for modeling, both for model inputs and for model evaluation, are very limited or non-existent. The overall objective of this research was to enable development of watershed management plans for agricultural dominated systems under situations where data are scarce. First, uncertainty of the SWAT modelâ s outputs due to input parameters, specifically soils and high resolution digital elevation models, which are likely to be lacking in data-poor environments, was quantified using Monte Carlo simulation. Two sources of soil parameter values (SSURGO and STATSGO) were investigated, as well as three levels of DEM resolution (10, 30, and 90 m). Uncertainty increased as the input data became coarser for individual soil parameters. The combination of SSURGO and the 30 m DEM proved to adequately balance the level of uncertainty and the quality of input datasets. Second, methods were developed to generate appropriate soils information and DEM resolution for data-poor environments. The soils map was generated based on lithology and slope class, while the soil attributes were generated by linking surface soil texture to soils characterized in the SWAT soils database. A 30 m resolution DEM was generated by resampling a 90 m DEM, the resolution that is readily available around the world, by direct projection using a cubic convolution method. The effect of the generated DEM and soils data on model predictions was evaluated in a data-rich environment. When all soil parameters were varied at the same time, predictions based on the derived soil map were comparable to the predictions based on the SSURGO map. Finally, the methodology was tested in a data-poor watershed in Bolivia. The proposed methodologies for generating input data showed how available knowledge can be employed to generate data for modeling purposes and give the opportunity to incorporate uncertainty in the decision making process in data-poor environments.
Ph. D.

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Abou, El Goud Amal Karam Sayed Ahmed. "Effect of endomycorrhizal fungi and compost on the yield and quality of maize and sunflower plants in poor nutrients soil." Kassel Kassel Univ. Press, 2010. http://d-nb.info/1003132960/04.

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Abou, El Goud Amal Karam Sayed Ahmed [Verfasser]. "Effect of Endomycorrhizal Fungi and Compost on the Yield and Quality of Maize and Sunflower Plants in Poor Nutrients Soil / Amal Karam Sayed Abou El-Goud." Kassel : Kassel University Press, 2010. http://d-nb.info/1016840985/34.

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Wadgaonkar, Shrutika. "Nouveaux procédés de bioremédiation pour le traitement des sols et des sédiments sélénifères." Thesis, Paris Est, 2017. http://www.theses.fr/2017PESC1105.

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L'objectif de cette thèse a été de développer une technologie pour l'assainissement des sols / sédiments sélénifères et d’étudier la réduction microbienne des oxy-anions de sélénium dans différentes conditions de respiration et de configurations du bioréacteur.Le sol sélénifère prélevé, dans les terres agricoles cultivées de blé au Pendjab (Inde), a été caractérisé et son lavage a été optimisé en faisant varier les paramètres tels que le temps de réaction, la température, le pH et le rapport liquide / solide. Afin de maximiser l'élimination et la récupération du sélénium à partir de ce sol, l'effet des ions compétiteurs et les composés oxydants comme les agents d'extraction pour le lavage du sol, ont également été étudiés. Bien que les agents oxydants aient montré une efficacité maximale d'élimination du sélénium (39%), la présence d'agents oxydants dans le lixiviat et le sol agricole peut augmenter le coût de leur post-traitement. Les plantes aquatiques, Lemma minor et Egeria densa ont été utilisées pour étudier la phyto-remédiation du lixiviat du sol contenant des agents oxydants. Cependant, l'efficacité d'élimination du sélénium par les plantes aquatiques a été significativement affectée par les fortes concentrations de ces agents oxydants dans le lixiviat du sol.Le rinçage du sol sélénifère a révélé un motif de migration du sélénium à travers la colonne du sol. La migration de la fraction de sélénium soluble de la couche supérieure vers la couche inférieure et sa réduction et son accumulation subséquentes dans les couches inférieures de la colonne de sol, ont été observées pendant le rinçage du sol. L'efficacité d'élimination du sélénium par la méthode de rinçage du sol a diminué avec une augmentation de la hauteur de la colonne. De plus, le lixiviat contenant des oxy-anions de sélénium obtenus à partir du lavage du sol, a été traité dans un réacteur UASB en faisant varier l'alimentation organique. Des effluents contenant moins de 5 μg de sélénium L-1 ont été obtenus, ce qui est conforme aux normes de l'USEPA pour la limite de rejet de sélénium dans les eaux usées.De plus, la bio-remédiation ex situ des oxy-anions de sélénium a été étudiée dans des conditions variables. Une bactérie aérobie (Delftia lacustris) capable de transformer le sélénate et le sélénite en sélénium élémentaire, mais aussi en composés d'ester de sélénium solubles jusque-là inconnus, a été isolée et caractérisée de manière fortuite. Alternativement, la bio-réduction anaérobie du sélénate couplé au méthane en tant que donneur d'électrons, a été étudiée dans des bouteilles de sérum et un filtre percolateur en utilisant des sédiments marins comme inoculum. Enfin, l'effet de la contamination d'autres oxy-anions chalcogènes, en plus du sélénium, a été étudié. La réduction simultanée de la sélénite et de la tellurite par un consortium microbien mixte ainsi que la rétention des nanostructures de Se et de Te biogènes dans l'EPS, ont été réalisées durant une opération de 120 jours dans un bioréacteur UASB
The aim of this Ph.D. was to develop a technology for the remediation of seleniferous soils/sediments and to explore microbial reduction of selenium oxyanions under different respiration conditions and bioreactor configurations.Seleniferous soil collected from the wheat-grown agricultural land in Punjab (India) was characterized and its soil washing was optimized by varying parameters such as reaction time, temperature, pH and liquid to solid ratio. In order to maximize selenium removal and recovery from this soil, effect of competing ions and oxidizing agents as chemical extractants for soil washing were also studied. Although oxidizing agents showed a maximum selenium removal efficiency (39%), the presence of oxidizing agents in the leachate and the agricultural soil may increase the cost of their post-treatment. Aquatic plants, Lemma minor and Egeria densa were used to study phytoremediation of the soil leachate containing oxidizing agents. However, the selenium removal efficiency by aquatic weeds was significantly affected by the high concentrations of these oxidizing agents in the soil leachate.Seleniferous soil flushing revealed the selenium migration pattern across the soil column. Migration of soluble selenium fraction from the upper to the lower layers and its subsequent reduction and accumulation in the lower layers of the soil column was observed during soil flushing. The selenium removal efficiency by the soil flushing method decreased with an increase in the column height. Furthermore, the soil leachate containing selenium oxyanions obtained from soil washing was treated in a UASB reactor by varying the organic feed. Effluent containing less than 5 μg L-1 selenium was achieved, which is in accordance with the USEPA guidelines for selenium wastewater discharge limit.Moreover, ex situ bioremediation of selenium oxyanions was studied under variable conditions. An aerobic bacterium (Delftia lacustris) capable of transforming selenate and selenite to elemental selenium, but also to hitherto unknown soluble selenium ester compounds was serendipitously isolated and characterized. Alternatively, anaerobic bioreduction of selenate coupled to methane as electron donor was investigated in serum bottles and a biotrickling filter using marine sediment as inoculum. Finally, the effect of contamination of other chalcogen oxyanions in addition to selenium was studied. Simultaneous reduction of selenite and tellurite by a mixed microbial consortium along with the retention of biogenic Se and Te nanostructures in the EPS was achieved during a 120-day UASB bioreactor operation

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Rodriguez, Tiago Garcia. "Caracterização geotécnica de um solo de diabásio por meio de ensaios SPT e CPT." [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/258775.

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Orientador: Paulo José Rocha de Albuquerque
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo
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Resumo: A presente dissertação tem por objetivo apresentar a caracterização geotécnica do solo de diabásio do Campo Experimental da Faculdade de Engenharia Civil da Unicamp, por meio de ensaios de campo SPT e CPT. Verificar a adequabilidade dos ensaios as condições do solo tropical, lateritico, típico da região de Campinas, por meio de proposicoes de classificação de comportamento de solos e da estimativa de parâmetros geotécnicos, assim como as possíveis correlações, teóricas e empíricas, entre os dois ensaios. Foram utilizados ensaios de cone, mecânico e elétrico, e ensaios SPT com medição de energia. As propostas para classificações dos tipos de solo, através do CPT, utilizadas indicaram duas camadas distintas a primeira de solos de comportamento arenosos a silto-arenosos e a segunda de solos de comportamento siltosos a siltoargilosos, em concordância com a classificação obtida em laboratório. As proposicoes utilizadas para estimativa de parâmetros geotécnicos tiveram que ser ajustadas para o solo do campo experimental. A correlação (qc/pa)/N60 obtida foi de 4 para o solos coluvionar (areno-siltoso) e 2,5 para o solo residual (siltoso) em concordância com os valores encontrados na literatura
Abstract: The purpose of this dissertation is to present the geotechnical characterization of the diabasic soil of the Experimental Field of the Unicamp School of Civil Engineering by means of SPT and CPT field trials, and to check the adequacy of such trials to the conditions of the tropical, lateritic soil, which is typical of the Campinas region by means of propositions to classify the behavior of the soils and estimation of geotechnical parameters, as well as possible theoretical and empirical correlations between the two trials. Cone, mechanical and electrical trials were used as well as SPT trials with measurement of energy. The proposals used to classify the types of soil via CPT indicated two separate layers: the first one with soils with sandy to silty-sandy behavior, and the second layer of soils with silty to silty-clayey behavior, in agreement with the laboratory classification. The propositions used to estimate the geotechnical parameters had to be adjusted to the soil of the experimental field. The correlation (qc/pa)/N60 obtained was 4 for colluvial soil (sandy-silty), and 2.5 for residual soil (silty) in agreement with the values found in the literature
Mestrado
Geotecnia
Mestre em Engenharia Civil

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Barbosa, Luís Alfredo Pires. "Compactação do solo gerada por pneus de alta flutuação de eixo livre e trativo." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/256834.

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Orientador: Paulo Sérgio Graziano Magalhães
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agrícola
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Resumo: O aumento da mecanização das lavouras gera o emprego de máquinas cada vez mais potentes e, a potência possui relação direta com o peso. Aumentando-se o tráfego de máquinas pesadas sobre o solo o emprego do pneu correto é de suma importância para se minimizar os efeitos da compactação. Com as diferenças entre os modelos de pneus de alta flutuação para eixos livres e trativos (com garras) e o comum emprego de pneus trativos em eixos livres devido ao seu custo de imposto ser reduzido, questionou-se a possibilidade de o emprego do pneu mais barato estar prejudicando a produtividade, pelo fato de apresentar uma área de contato possivelmente menor. Objetivou-se ao estudo comparativo entre dois modelos de pneus de alta flutuação da mesma medida, porém um para eixos livres e outro para eixos trativos. Os experimentos foram conduzidos em caixa de solos e também em superfície rígida, sob condições controladas, realizando-se ensaios estáticos para duas cargas radiais (16 e 29 kN), medindo-se deformações, áreas de contato e compactação do solo, sendo feita uma análise estatística fatorial, com os fatores pneu e carga, sendo realizados 8 ensaios, totalizando 32 observações. Obteve-se como resultados, deformações maiores para o pneu trativo, bem como área de contato maior e compactações menores, que o pneu de eixo livre, isso porque a área de contato do pneu trativo envolve não somente as garras, mas também o fundo íncavo (região entre garras), para o solo estudado, e o fato do pneu possuir uma quantidade de composto de borracha menor em sua banda de rodagem, quando comparado com o pneu de eixo livre, aumenta a flexibilidade da rodagem, melhorando sua capacidade de deformação e consequentemente aumentando sua área de contato com o solo
Abstract: The increased mechanization in farming generates employment of ever more powerful machines, and power has direct relationship with the weight. Increasing traffic of heavy machinery on the ground the use of correct tire is of paramount importance to minimize the effects of compaction. With the differences between models of high-flotation tires for free and trative axes, especially regarding the presence of claws, and the common use of tires trative on free axes because of the cost of tax be reduced, questioned the possibility of employment tire cheaply be hindering productivity, because this has a contact area possibly lower. The objective is then to the comparative study between two models of high-flotation tires the same size, but one for free axes and another for trative axes. The experiments were conducted in soil bin and also in rigid surface, under controlled conditions, performing static tests for two radial loads (16 and 29 kN), by measuring deformation, contact areas and soil compaction, and made a factorial statistical analysis with the tire and load factors, was conducted 8 tests, totaling 32 observations. Was obtained as result, larger deformations for the trative tire as well as larger contact area and less compaction of the soil that tire of free axis, that because the contact area of the tire tractive involves not just the claws, but also the region between them and the fact that the tire has a much lower rubber compound in its tread, when compared with tire of free axis, increases flexibility, enhancing their ability to deformation and consequently increasing its contact area with the ground, reducing the compaction of soil
Mestrado
Maquinas Agricolas
Mestre em Engenharia Agrícola

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Fatras, Christophe. "Etude de la rétrodiffusion altimétrique pour la caractérisation des surfaces et de l'humidité des sols en Afrique de l'Ouest." Thesis, Toulouse 3, 2015. http://www.theses.fr/2015TOU30106/document.

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Le satellite altimétrique interférométrique SWOT, dont le lancement est prévu pour 2020, devrait pour la première fois permettre une couverture globale en quelques jours d'un radar proche-nadir en utilisant la bande de fréquence Ka. Or, l'utilisation d'une telle bande de fréquence est encore mal documentée pour l'hydrologie continentale. En particulier, le contraste du coefficient de rétrodiffusion sur les sols et sur les surfaces en eau pour des angles de visée nadir et proche nadir est une problématique majeure. C'est ce qui fait l'objet de ces travaux de thèse. Dans un premier temps, l'étude de la variation des coefficients de rétrodiffusion en provenance d'altimètres en bandes C et Ku et de diffusiomètres utilisant les mêmes bandes de fréquence sur l'Afrique de l'Ouest a montré qu'il existe un lien quantifiable entre l'humidité du sol et le coefficient de rétrodiffusion. En région semi-aride ce lien se manifeste via une hausse des coefficients de rétrodiffusions durant la saison humide par rapport à la saison sèche. L'analyse avec des données annexes d'humidité du sol et de précipitations a pu également montrer que le radar nadir détecte plus précisément les changements d'humidité du sol par rapport à la diffusiométrie radar à visée latérale. Dans le but de mieux comprendre la rétrodiffusion en bande Ka, très peu documentée, deux campagnes de mesures radar ont été réalisées, l'une sur des surfaces en eau à rugosité contrôlée, l'autre sur un terrain contrôlé en rugosité et humidité du sol. En parallèle, un programme de simulation de la rétrodiffusion altimétrique a été développé pour pouvoir analyser les effets d'un faible nombre de variables sur des sols réalistes, dans le but de simuler les variations du coefficient de rétrodiffusion. Ces mesures et ces simulations ont ensuite pu être comparées aux séries temporelles issues du satellite altimétrique AltiKa, fonctionnant en bande Ka et lancé en février 2013, sur différents sites représentatifs des régions bio-climatiques d'Afrique de l'Ouest. Il en ressort que la bande Ka présente une forte sensibilité aux changements d'humidité du sol. Il est également montré que les coefficients de rétrodiffusion en provenance d'AltiKa sur les sols et sur l'eau peuvent être similaires au nadir
The radar altimetry interferometry satellite SWOT, which is to be launched in 2020, should provide for the first time a global coverage of a close-to-nadir radar altimeter in a few days using the Ka-band. Yet, the use of such a frequency band for continental hydrology is still poorly documented. In particular, the contrast of the backscattering coefficient over soils and over water bodies for nadir and close-to-nadir angles is a major issue. This is the reason for this work. First, the study of the backscattering coefficients from C- and Ku- band altimeters and scatterometers over West Africa has shown that there is a link between the surface soil moistureand the backscattering coefficient. In semi-arid regions, this link is seen through a rise of the backscattering coefficients during the rainy season compared to the dry season. The analysis with ancillary data such as the surface soil moisture and the precipitation estimations has also shown that nadir-looking radars detect more precisely the changes in surface soil moisture compared to side-looking radars. Still with the purpose to better understand the Ka-band surface scattering, poorly documented, two measurement campaigns were led, on the one hand over water surface with controlled roughness, on the other hand over bare soils with monitored roughness and surface soil moisture. In parallel, an altimetry backscattering simulation program has been developed to analyze the effect of a low number of variables on realistic grounds, with the aim of simulating the backscattering coefficient variations. These measurements and simulations were then compared with time series from the satellite altimeter AltiKa, which has been launched in 2013 and works at Ka-band, over different sites representaing the bioclimatic areas of West Africa. It led to a high sensitivity of the Ka-band to changes in the surface soil moisture. It has also been shown that backscattering coefficients at nadir-looking angle from AltiKa over grounds and over water bodies can be similar

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Saenger, Anaïs. "Caractérisation et stabilité de la matière organique du sol en contexte montagnard calcaire : proposition d'indicateurs pour le suivi de la qualité des sols à l'échelle du paysage." Thesis, Grenoble, 2013. http://www.theses.fr/2013GRENS010/document.

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Les sols de montagne représentent d'importants réservoirs de carbone (C) potentiellement vulnérables aux changements climatiques et changements d'usage qui les affectent de manière amplifiée. Or la grande variabilité de ces milieux, leur faible accessibilité ainsi que le manque d'outils de mesure appropriés limitent nos connaissances qui restent aujourd'hui très fragmentaires en ce qui concerne les stocks, la chimie et la réactivité du carbone organique des sols (COS). Ces informations sont pourtant nécessaires pour appréhender l'évolution de ces sols et de leur C dans ce contexte de changements globaux. Les objectifs de ce travail de thèse étaient (i) d'accéder à une meilleure compréhension de la nature, de la stabilité et de la vulnérabilité du COS dans une mosaïque d'écosystèmes des Préalpes calcaires (massif du Vercors), (ii) de rechercher des outils de caractérisation rapides et fiables adaptés à l'étude et au suivi du COS à l'échelle du paysage, et enfin (iii) de proposer des indices pour l'évaluation et le suivi de la qualité des sols en milieu de montagne. Dans un premier temps, nous avons testé l'application de la pyrolyse Rock-Eval pour l'étude du COS à grande échelle sur un ensemble d'unités écosystémiques. Nous avons ensuite comparé la pyrolyse Rock-Eval à deux techniques classiques d'étude de la matière organique du sol (MOS) : le fractionnement granulodensimétrique de la MOS et la spectroscopie moyen infrarouge. Ces approches analytiques couplées nous ont permis de quantifier les stocks de C à l'échelle de la zone d'étude et d'expliquer la stabilité et la vulnérabilité du COS sous des angles variés. Les facteurs responsables des patrons observés dans les différentes unités écosystémiques sont discutés. Ce travail a également confirmé la pertinence de l'outil Rock-Eval pour répondre aux objectifs fixés. Parallèlement, des approches biologiques nous ont permis d'évaluer l'importance de la composante microbienne dans ces sols. Enfin, des indices évaluant le statut organique des sols (stockage de COS, fertilité des sols, vulnérabilité du COS) sont proposés pour constituer des outils de gestion et d'aide à la décision
Mountain soils are major reservoirs of carbon (C), potentially vulnerable to climate and land use changes that affect them significantly. However, the great variability of these soils, their limited accessibility and the lack of appropriate measurement tools restrict our knowledge. Today, our comprehension of the biogeochemistry of mountain soils remains very incomplete regarding stocks, chemistry and reactivity of soil organic carbon (SOC). Yet this information is necessary to understand the evolution of soil carbon in the current context of global change. The objectives of this work were (i) to gain a better understanding of the nature, stability and vulnerability of SOC in a mosaic of ecosystems in a calcareous massif in the Alps (Vercors massif), (ii) to search for fast and reliable characterization tools, suitable for the study and monitoring of COS at the landscape scale, and (iii) to propose indicators for the assessment and monitoring of soil quality in mountain regions. As a first step, we tested the application of Rock-Eval pyrolysis for the study of COS at large-scale on a set of ecosystem units. Then, we compared the Rock-Eval approach to two conventional techniques for soil organic matter (SOM) study: the particle-size fractionation of SOM, and the mid-infrared spectroscopy. These coupled analytical approaches allowed us to quantify C stocks across the study area, and explain the stability and the vulnerability of COS at various angles. Factors responsible for the patterns observed in the different eco-units are discussed. This work also confirmed the relevance of the Rock-Eval tool to achieve our previous objectives. Biological approaches allowed us to assess the significance of microbial pool in these soils. Finally, indices assessing the status of SOM (SOC storage, soil fertility, vulnerability COS) were proposed and constituted interesting management tools for decision-makers

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Silva, Moreira Cindy. "Stocks de carbone du sol dans les zones de reboisement : bases pour projets de mécanisme pour un développement propre." Thesis, Montpellier 2, 2010. http://www.theses.fr/2010MON20228/document.

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Malgré l'importance de la séquestration du carbone (C) dans les sols forestiers, il existe actuellement peu de projets Mécanisme pour un Développement Propore (MDP) qui tiennent compte de la gestion de ce compartiment dans l'atténuation du réchauffement climatique. La cause principale est que l'accréditation du carbone séquestré dans le sol représente de plus grands défis et des risques par rapport aux autres composantes des écosystèmes forestiers.Connaissant les difficultés économiques et les problèmes environnementaux impliqués dans l'adoption d'un tel projet et l'importance des forêts dans l'atténuation du changement climatique, l'objectif de cette étude était d'évaluer les performances des méthodes dedétermination des stocks de carbone du sol dans deux projets de reboisement, ainsi que pour leurs situations de références (c'est-à-dire utilisation des terres avant la plantation, des pâturages naturels, ainsi que la végétation native) comme base pour diminuer le rapport coût bénéfice des projets MDP dans le secteur forestier. Pour atteindre l'objectif principal, cestravaux de recherches ont consisté à l'étude de: (i) la variabilité spatiale du C du sol dans une zone de reboisement avec des espèces indigènes, établi dans le bassin amazonien dans le MatoGrosso à Cotriguaçu (Zone I) et une chronoséquence de plantations d'Eucalyptus, située dansl'état de São Paulo à Avare (zone II); (ii) la taille des parcelles et la distance idéale de séparation des échantillons à partir de l'étude de la dépendance spatiale du C, (iii)l'estimation de la teneur en C et la densité du sol (Ds) par spectroscopie dans le proche(NIRS) et moyen (MIRS) infrarouge, afin de réduire les coûts sans affecter la qualité des résultats analytiques : et (iv) du calcul des stocks de C du sol pour ces deux projets et l'estimation du bilan C du projet MDP menées dans la zone II, en utilisant l'outil EX-ACT («EX-Ante Carbon-balance Tool»). Les résultats ont confirmé l'existence d'une variabilité spatiale importante du C du sol, ainsi qu'une forte dépendance spatiale pour tous les traitements étudiés. L'analyse du nombre optimal d'échantillons de sol a montré que la collecte de cinq points par parcelle est aussi précise qu'un échantillonnage plus dense. La taille optimale des parcelles a été estimée de 361 à 841 m2 dans les plantations de la zone I et de 900 à 3721 m2 pour la Zone II. La performance de la spectroscopie MIRS et NIRS pourestimer la teneur en C des sols a été jugée très satisfaisante, surtout quand les modèles ont été étalonnés à partir de sous populations constituées de 10 à 50% de l'ensemble des données.Les résultats de l'estimation de Ds ont été légèrement moins satisfaisants que ceux pour le Cdu sol. Les stocks de C dans le sol calculés pour la zone I étaient supérieurs à ceux de la zone II. Si on ne considère que le compartiment du sol, il apparaît que le potentiel de génération de crédits C est plus important dans le reboisement à partir d'espèces indigènes dans un sol argileux que pour un reboisement d'eucalyptus dans un sol sableux. Le bilan C du projet de la zone I a montré un potentiel de séquestration de près de trois millions de tonnes d'équivalentCO2 en 40 ans. Il est espéré que cette étude qui montre des possibilités de réduction des coûts liés aux calculs des stocks de C du sol contribuera à une meilleure prise en compte de ce compartiment dans les projets MDP forestiers
Considering the great importance of carbon sequestration (C) in forest soils, there are fewCDM projects that include this compartment as an agent of global warming mitigation. Thisoccurs because the quantification of soil C stocks represents a bigger challenge whencompared to other components of forest ecosystems. Considering the economic difficultiesand environmental issues involved in adopting this type of project and the importance offorests in mitigating climate change, the objective of this study was to evaluate theperformance of methods for obtaining soil C stocks in two forestry areas and their respectivebaselines (land use prior to planting, i.e. pastures and native vegetation) as a basis forreducing the cost-benefit ratio of CDM projects. To achieve the main objective, this researchwas composed of the following steps: (i) estimating the spatial variability of soil C in an areareforested with native species, established in Cotriguaçú, MT (Area I) and a Eucalyptuschronosequence, located in Avaré, SP (Area II), (ii) determining the optimal amount of soilsamples and the plot size from the soil C spatial dependence range in the reforestation areas,(iii) estimating soil C content and bulk density (BD) by Near and Mid Infrared ReflectanceSpectroscopy (NIRS and MIRS, respectively) to reduce analytical costs without affecting thequality of the results, and (iv) calculating soil C stocks in both areas and estimating the carbonbalance of a CDM Project conducted in Area II, using EX-ACT ("Ex-Ante Carbon BalanceTool"). The results confirmed the existence of significant soil C spatial variability in bothareas and a strong spatial dependence at all plots. The analysis of the optimal number of soilsamples indicated that the sampling procedure with five points per plot is as accurate asintensive sampling. The optimum size of plots ranged from 361-841 m2 at Area I plantationsand from 900-3721 m2 at Area II. The performance of MIRS and NIRS to estimate the soilcarbon content was very satisfactory, especially when the models were calibrated withamounts between 5-10% of the total data set. The estimations of BD were slightly less precisethan those of soil C content. The soil C stocks obtained at Area I were higher than Area II.Considering only the soil compartment, it is clear that the potential for C credit generation in areforestation with native species on a clayey soil is higher than in a reforestation witheucalyptus on a sandy soil. The C balance of the CDM project conducted in Area I is expectedto sequester almost three million tones of CO2 eq in 40 years. We hope this study contributesto the increased inclusion of soil in CDM projects, by confirming the feasibility of reducingthe costs associated with both sampling and analytical procedures

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Jahangir, Emad. "Phénomènes d'interaction sol-structure vis-à-vis de l'aléa retrait-gonflement pour l’évaluation de la vulnérabilité des ouvrages." Thesis, Vandoeuvre-les-Nancy, INPL, 2011. http://www.theses.fr/2011INPL088N/document.

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Les sols argileux peuvent présenter des variations importantes de volume lors d’un changement hydrique, tel une période de sécheresse. Ce phénomène de retrait-gonflement des sols argileux est à l’origine de nombreux préjudices aux bâtis ce qui le situe, après les inondations, au second rang des aléas naturels français en matière de coût des dommages : 5 milliard d’euros entre 1988 et 2007. Les maisons individuelles sont les plus touchées par ce phénomène qui provoque un tassement différentiel du bâti à l’origine de sa dégradation (fissures dans les éléments de maçonnerie non armée en particulier). L’objectif de cette thèse est d’étudier la vulnérabilité des bâtis vis-à-vis de l’aléa retrait-gonflement à travers une analyse de l’interaction sol-structure. Ce travail s’est porté sur les trois grands volets suivants : 1 - le comportement hydromécanique des sols argileux, 2 - l’interaction sol-structure, 3 - l’évaluation des dommages structuraux. Le comportement hydromécanique des sols argileux a été modélisé par le concept de surface d’état et intégré dans un modèle d’interaction sol-structure inspiré du modèle de Winkler, avec des approches de plus en plus complexes : cas unidimensionnel tout d’abord, 2D ensuite en assimilant la structure à une poutre, puis en 3D en représentant la structure par une plaque. Ces modèles d’interaction sol-structure permettent de calculer la déflexion relative d’un bâti, en fonction d’une valeur de succion imposée et des propriétés mécaniques ou hydromécaniques de la structure et du sol d’assise. La déflexion relative du bâti est alors comparée à des valeurs seuils afin d’évaluer le dommage.La dernière partie de cette thèse consiste en une étude de faisabilité pour le développement de courbes de vulnérabilités adaptées à la problématique du retrait gonflement. Ces courbes représentent la moyenne des dommages d’un type de bâti conçu sur un type de sol gonflant pour une valeur de succion imposée. Ces courbes ont été développées à partir d’une typologie des sols gonflants et d’une typologie des bâtis issue des bases de données des maisons sinistrées. La moyenne des dommages est calculée par la méthode de Monte-Carlo, en prenant en compte la variabilité des paramètres du bâti
Clayey soils can present large volumetric deformations in response of water content change. This phenomenon of shrinkage and swelling of clayey soils is recognized as a costly natural hazard throughout the world. In France, this cost is reported between 1988 and 2007 to 5 million Euros, ranking in second class of the French natural hazards in terms of cost of damage after the floods. The individual masonry buildings with shallow foundations are the most affected by this phenomenon that causes a differential settlement of the building leading to cracks in facades and structural elements, especially in unreinforced masonry elements.The objective of this thesis was to study the vulnerability of the building, against the shrink-swell hazard through an analysis of soil-structure interaction. This work was focused on three major points: - Hydro-mechanical behavior of clay soils - Soil-structure interaction - Evaluation of structural damage.The hydro-mechanical behavior of clay soils was considered by the concept of state surface and integrated into a soil-structure interaction model, based on the Winkler model, with increasingly complex approaches: 1D, 2D and 3D by modeling the building behavior respectively by a spring system, the beam element and the plate element. These models of soil-structure interaction are able to calculate the relative deflection of the building, according to the values of imposed suction, mechanical properties of the structure and hydro-mechanical properties of the soil. The relative deflection of the building is then compared to threshold values of the classical damage categories to assess the building damage.Finally a feasibility study was conducted on the development of vulnerability curves adapted to the problem of shrinkage – swelling of clayey soils. These curves represent the average of structural damage versus suction, for each type of building. These curves were developed based on a classification of expansive soils and a building typology outcome from databases of affected buildings. The average damage is calculated by the Monte-Carlo method, taking into account the variability of the building parameters

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Cauvier, Jacques. "Renouveler le rapport à son corps, pour un renouvellement de soi et de sa pratique À la recherche d'un équilibre entre le soin de soi et le soin des autres /." Thèse, [Rimouski, Québec] : Université du Québec à Rimouski, 2007.

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Thèse (M. A.) -- Université du Québec à Rimouski, 2007.
Titre de l'écran-titre (visionné le 1er novembre 2007). Mémoire présenté à l'Université du Québec à Rimouski comme exigence partielle du programme de maîtrise en études des pratiques psychosociales. Comprend un résumé. CaQRU CaQRU CaQRU Bibliogr.: f. 151-158. Publié aussi en version papier. CaQRU

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Maghoul, Pooneh. "Solutions fondamentales en Géo-Poro-Mécanique multiphasique pour l'analyse des effets de site sismiques." Phd thesis, Université Paris-Est, 2010. http://tel.archives-ouvertes.fr/tel-00599397.

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Ce travail de recherche se situe dans le cadre du développement de la méthode des éléments de frontière (BEM) pour les milieux poreux multiphasiques. À l'heure actuelle, l'application de la BEM aux pr oblèmes des milieux poreux non-saturés est encore limitée, car l'expression analytique exacte de la solution fondamentale n'a pas été obtenue, ni dans le domaine transformé ni dans le domaine réel. Ceci provient de la complexité du système d'équations régissant le comportement des milieux poreux non-saturés. Les développements de la BEM pour les sols non-saturés effectués au cours de cette thèse sont basés sur les modèles thermo-hydro-mécanique (THHM) et hydro-mécanique (HHM) présentés dans la première partie de ce mémoire. Ces modèles phénoménologiques basés sur la théorie de la poromécanique et les acquis expérimentaux sont obtenus dans le cadre du modèle mathématique présenté par Gatmiri (1997) et Gatmiri et al. (1998). Après avoir présenté les modèles THHM et HHM, on établit pour la première fois les équations intégrales de frontière et les solutions fondamentales associées pour un milieu poreux non-saturé sous chargement quasi-statique pour les deux cas isotherme (2D dans le domaine de Laplace) et non-isotherme (2D et 3D dans les domaines de Laplace et temporel). Aussi, les équations intégrales de frontière ainsi que les solutions fondamentales 2D et 3D (dans le domaine de Laplace) pour le modèle dynamique couplé des sols non-saturés sont obtenues. Ensuite, les formulations d'éléments de frontière (BEM) basées sur la méthode quadrature de convolution (MQC) concernant les milieux poreux saturé et non-saturé sous chargement quasi-statique isotherme et dynamique sont implémentées dans le code de calcul " HYBRID ". Ayant intégrées les formulations de BEM pour les problèmes de propagation d'ondes ainsi que pour les problèmes de consolidation dans les milieux poreux saturés et non-saturés, il semble que nous ayons fourni à l'heure actuelle le premier code de calcul aux éléments de frontière (BEM) qui modélise les différents problèmes dans les sols secs, saturés et non-saturés. Une fois le code vérifié et validé, des études paramétriques portant sur des effets de site sismiques sont effectuées. Le but recherché est d'aboutir à un critère simple, directement exploitable par les ingénieurs, combinant les caractéristiques géométriques et les caractéristiques du sol, permettant de prédire l'amplification du spectre de réponse en accélération dans des vallées sédimentaires aussi bien que vides

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Van, der Poel Petrus W. "Plunge pool erosion in cohesive channels below a free overfall /." Connect to resource, 1985. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1202403267.

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Basmaji, Bakri. "Développement d’un modèle analytique d’interaction sol-structure pour l'étude du comportement mécanique des structures soumises à un mouvement de terrain : influence des déformations de cisaillement et de la plasticité." Thesis, Université de Lorraine, 2016. http://www.theses.fr/2016LORR0290/document.

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Ce travail s'inscrit dans la continuité des travaux de recherche menés au laboratoire Géoressources (Ecole des Mines de Nancy) et à l'INERIS depuis plusieurs années. Il concerne l’évaluation de la vulnérabilité des ouvrages situés dans des zones de mouvement de terrains d’origine naturelle ou anthropique. L’objectif de la thèse est de développer un modèle analytique permettant l’évaluation du tassement différentiel d’un ouvrage soumis à un mouvement de terrain et de calculer le taux de transmission de ces mouvements en fonction de la rigidité relative de l’ouvrage. Le modèle d’interaction sol-structure développé, tient compte de l’influence des contraintes de cisaillement dans le bâti et le terrain et d’un comportement poste-rupture du sol grâce à l’introduction d’une limite de plasticité. Le sol a été modélisé par les éléments de Pasternak afin de prendre en compte l'influence des déformations de cisaillement dans le sol, alors que le bâtiment est modélisé par la poutre d'Euler-Bernoulli et par la poutre de Timoshenko. L’existence potentielle d’un vide (décollement) sous le bâtiment a également été prise en compte dans le modèle analytique développé. Le taux de transmission des mouvements en champ libre du terrain au bâtiment a été calculé et présenté en fonction de la rigidité relative en flexion du bâtiment par rapport au terrain. Pour valider le développement entrepris, les résultats du modèle analytique ont été comparés aux résultats de modèles existants, analytiques, numériques et expérimentaux développés principalement par l'Université de Cambridge. Les résultats obtenus sont très satisfaisants et permettant de confirmer la robustesse du modèle analytique développé
This work is a continuation of the research work conducted in the Géoressources Laboratory and INERIS since several years. It concerns the assessment of the vulnerability of masonry structures influenced by natural or induced ground movements. The origins of the movement are may be, mining subsidence, tunneling, and shrinkage-swelling of clayed ground. The objective of the thesis is to develop an analytical model to evaluate the differential settlement of a structure in relation to the free field ground movement and given a set of phenomena: soil-structure interaction, influence of shear deformations in the structure and the ground, influence of non- linearities induced by the ground yielding. The soil was modeled by Pasternak elements to take into account the influence of shear deformations in the soil, while the building is modeled by the Euler-Bernoulli beam and by the beam of Timoshenko. The possibility of having a gap under the building was also taken into account. The deflection transmission ratio is then calculated and plotted according to are lative stiffness ratio which depend on both the structure and the soil stiffness A numerical model is also developed and results are compared with those of the analytical model. Other results of several numerical and experimental models principally developed at the University of Cambridge are also used for this comparison. Results show significant consistence between all these results. This demonstrates the significance of the analytical soil-structure model developed in this thesis

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De, La Motte Saint Pierre Mathieu. "Microfluidique digitale pour la croissance de micro-organismes difficiles à cultiver." Thesis, Paris Sciences et Lettres (ComUE), 2017. http://www.theses.fr/2017PSLET039/document.

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Le sol constitue le milieu naturel contenant la plus grande diversité de micro-organismes (typiquement 109 cellules de 104 espèces différentes par gramme de terre). Pourtant il n’est possible d’obtenir la croissance que d’une fraction en laboratoire (moins de 5 %). Réaliser des cultures de cette diversité, inaccessible pour le moment, aurait des applications considérables en agriculture (création d’engrais ou pesticide biologique et respectueux de l’environnement) et en pharmacologie (découverte d’antibiotiques ou anticancéreux). Ce travail de thèse est principalement axé sur l’étude de la croissance de micro-organismes difficiles à cultiver issus d’échantillons naturels tels que les sols. Des gouttes de tailles micrométriques, créées par microfluidique digitale, sont utilisés comme microréacteurs afin d’obtenir la croissance en laboratoire des espèces microbiennes encapsulées à l’intérieur. Une première étape consiste à obtenir une solution ne contenant que les microbes provenant de notre échantillon naturel de sol pour pouvoir réaliser l’encapsulation sans matières minérales et obtenir une diversité la plus proche possible de celle du sol. Une deuxième étape consiste à encapsuler les cellules contenues dans notre solution en faisant varier certaines conditions comme : la concentration initiale de microbes, le milieu de culture ou le temps d’incubation. Par l’observation des gouttes après croissance et séquençage des gènes ARNr 16S des cellules contenues à l’intérieur nous démontrons qu’il est possible d’obtenir la croissance de jusqu’à 40 % des espèces. Cette méthode microfluidique ouvre la voie du criblage à haut débit des interactions entre une espèce donnée (pathogène humain ou de plante, phage/virus) avec le microbiote qu’il est susceptible de contaminer (flore intestinal, sols, mers …) et ainsi déterminer quantitativement la réaction du milieu étudié, en plus de son utilisation pour la croissance d’espèces difficilement cultivables en laboratoire
Soil is the natural medium containing the highest microbial diversity (109 cells from 104 different species per gram of soil). Yet we still can’t grow in laboratory more than 5 % of them. Having access to this diversity will lead to crucial applications for farming (production of organic fertilizers or environmentally friendly pesticides) and to pharmacology (discovery of new antibiotics or new anticancer molecules). This work focuses on the study of growth of non culturable micro-organisms from natural samples, like soil. This method uses microfluidics droplets as microreactors to obtain the growth of microbial species encapsulated inside. The first step is to achieve a solution with nothing but the microbes from our natural sample (no minerals) for a successful encapsulation and obtain diversity as close to the one found in the soil. The second step is to encapsulate the cells from this solution with different set of condition like : initial concentration, growth media and incubation time. By coupling observation of the droplets after growth and the rRNA 16S sequencing of their content we demonstrate that it is possible to obtain the growth of up to 40 % of the species. This microfluidic method, besides its use in growing unculturable species in laboratory, opens the way towards high-throughput screening of interactions between a given species (human or plant pathogens, phage/virus) and the microbiota it is likely to contaminate (gut flora, soil, sea …) and obtain the quantitative determination the reaction of microbiota

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Noël, Annie-Françoise. "Pour une théorie du soin." Paris 10, 2010. http://www.theses.fr/2010PA100013.

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Le modèle théorique qui sert de référence commune aux pratiques (in)dividuelles et institutionnelles du soin, oppose contradictoirement Bien et Mal, santé et maladie, bons et méchants, forts et faibles, savants et ignorants, etc, dans un concept rationnel qui fabrique, subsume, assume et surmonte l’unité paradoxale de deux types de forces a priori tenues pour antinomiques : forces physiques « dangereuses » pour la pensée et forces transcendantales (« le bien ») « condamnées » à lutter contre ce « mal » qui les menacerait, et/ou inversement. A « l’application », ce modèle dialectique qui rend conflictuelles des forces qui ne le sont pas, place chacun en manque de pensée et de sensibilité. Ce qui conduit à obtenir le contraire du « bien » attendu : nature défigurée, vie menacée, rapports humains souvent cruels, mensongers ou cyniques. La structure paradoxale du modèle détermine des situations de double contrainte, certes surmontées en « théorie », mais insurmontables « en pratique », là où le concept prévoit de traiter par le mal ce qui résiste à son « bien ». De là, les croyances en l’onirisme de toute théorie, en la malignité de « l’homme », en une impossibilité ultime du soin et/ou en une contingence globale de ce dernier. Or, ce soin ironique, établi par un sujet identifié au Réel et de là asservi à la machinerie rationnelle qui lui sert de pensée, est symptomatique du soin authentique, lequel n’est pas placé sous l’autorité transcendante de ce sujet aliéné, mais tient nécessairement unies les forces physiques et transcendantales selon l’immanence radicale (du) Réel-Un (dont) elles sont chacune fonction dans leur ordre de réalité. Unies en-Dernière-Identité seulement, selon la structure de la dualité-unilatérale (non-philosophie), ces fonctions incommensurables agissent ensemble sans Dieu ni maître ni paradoxe. De là, ni « Bien » ni « Mal », seulement de la pensée, de la sensibilité, de la douceur, de la dignité, de la solidarité et de la coopération. En deux mots : de la Force (de) Soin
The theoretical model that makes common reference for (in)dividual and institutional practices of care and cure, sets up contradictory oppositions between Good and Evil, health and illness, the good and the bad, the strong and the weak, the learned and the ignorant, etc, in a rational concept that makes, subsumes, assumes and surmounts the paradoxical unity of two kinds of forces a priori deemed to be antinomical : natural forces “dangerous” to thought (“Evil”), and transcendental forces (“Good”), “sentenced” to struggle against the threat they are representing, and/or vice versa. In practice, this dialectical model forges conflicting forces, determines lacks of thought and sensibility and ends up achieving the opposite of the “good” expected : defaced nature, life threatened and human relations more often cruel, deceitful or cynical. The paradoxical structure of the model, actually traps everybody in double bind situations witch are surmounted “in theory”, but impossible to overcome “in practice”, where the concept compels one to be hard with everything that resists the “Good” it pretends to achieve. Hence, the faiths in theory’s unrealistic nature, in humans’ badness, in final impossibility of cure, and in care’s contingency. In fact, this ironical concept, settled by a subject identified with Real and thus enslaved to the rational machinery that serves to him as thought, is symptomatic of authentic Care, witch is not given under transcendent authority of this alienated subject, but keeps necessarily united, each one in its order of reality, physical and transcendental forces, according to the radical immanence (of) Real-One. United in-the-last-Identity only, these incommensurable functions (of) Real-One work together according to the Unilateral-duality’s structure (non-philosophy), without God nor Master, nor paradox. Hence : no “Good”, no “Evil”, only thought, sensibility, gentleness, dignity, solidarity and cooperation. In two words : Force (of) Care

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Freitas, Milena Cardoso de. "Avaliação de técnica de melhoria de solos colapsíveis por meio de colunas de solo laterítico compactado." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/18/18132/tde-28112016-095823/.

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A fundação direta é limitada em solos colapsíveis pois o efeito do colapso é mais acentuado nas camadas superficiais do terreno. Diante deste cenário, nesta pesquisa foi avaliada uma nova técnica de reforço de solo com a finalidade de viabilizar o uso de fundações diretas para controlar e reduzir o recalque das fundações devido ao colapso. A técnica proposta consiste na execução de colunas de solo laterítico compactado, inseridas na camada colapsível. O processo de compactação das colunas provoca a densificação do solo ao seu entorno, e consequentemente reduz a compressibilidade da massa de solo reforçado. Neste trabalho também foi verificado se a compactação radial do solo em torno da coluna estava relacionada com a geometria do pilão utilizado. Para compreender estes efeitos, foram realizados ensaios em laboratório, em escala reduzida, para avaliar qualitativamente duas geometrias de pilões diferentes, uma cônica e outra cilíndrica (tradicionalmente utilizada na engenharia de fundações). Como resultado desta análise, concluiu-se que a geometria cônica apresentou uma maior compactação lateral do solo no entorno da coluna, comparando-se com a geometria cilíndrica. Para analisar a eficiência do método de reforço proposto, foram executadas e ensaiadas colunas em escala real no solo colapsível do Campo Experimental de Fundações da Escola de Engenharia de São Carlos da Universidade de São Paulo. Para esta análise, foram realizadas provas de carga em placa em solo com e sem reforço. Os ensaios foram realizados com e sem a inundação do terreno para se verificar o efeito da inundação no comportamento do solo reforçado. Desta forma, foi possível avaliar o ganho de capacidade de carga e a redução dos recalques devido à execução dos elementos de reforço ensaiados. Por meio dos resultados obtidos nas provas de carga em placa constatou-se a eficiência do método na redução do recalque e no aumento da capacidade de carga. Comparando-se as curvas dos ensaios de placa com e sem reforço, observou-se um aumento da capacidade de carga de quatro vezes em consequência da instalação do reforço.
The use of shallow foundation is limited on collapsible soils due to the collapse effect pronounced in superficial layers. Considering this scenario, this research presents a new soil reinforcement technique in order to reduce the settlement of foundations due to the collapse. The proposed technique involves the execution of compacted lateritic soil columns inserted into the collapsible soil. The compaction of these columns causes the densification of the surrounding soil and consequently reduces compressibility of the reinforced soil mass. In this work, it was also evaluated the effect of the hummer geometry on the radial compaction of the soil around the column. For this evaluation, laboratory tests were conducted using two different geometries of hammer, one conical and other cylindrical (traditionally used in foundation engineering). The results showed that the conical geometry provided greater lateral compaction of the soil around the column compared to the cylindrical geometry. The efficacy of the compacted lateritic soil columns was evaluated by the results of plate load tests performed on the collapsible soil of the Experimental Field of the University of São Paulo in São Carlos city. The tests were carried out on a plate installed in the ground with and without reinforcement. The gain on bearing capacity and settlement reductions due to the reinforcement were verified by using these tests results. The tests were performed in natural and in flooded condition to verify the efficiency of the soil reinforcement in the flooding situation. Based on the results of the plate load tests, it was verified the efficacy of the method to reduce the effect of collapse. The load-displacement curves of the load tests showed that the solution evaluated provided an increase of 400% on the ultimate capacity of the plate installed on the collapsible soil tested in this investigation.

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Baroni, Axelle. "Modélisation du couplage sol-fluide pour la sismique entre puits." Châtenay-Malabry, Ecole centrale de Paris, 1996. http://www.theses.fr/1996ECAP0515.

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La propagation des ondes élastiques entre deux puits de forage est un problème complexe du fait de la génération d'ondes guidées: ces ondes à la fois présentes dans le puits émetteur et le puits récepteur, contiennent une information que l'on ne sait pas encore réellement exploiter. Modéliser une expérience de sismique entre puits permet de quantifier la génération, la diffraction et la radiation de ces ondes: c'est ce que propose le mémoire de cette thèse, à l'aide d'une technique hybride de sous-structuration dans laquelle les deux puits sont traités indépendamment: on couple pour cela des méthodes numériques et analytiques. On se ramène à un problème dont l'inconnue (déplacement et vecteur contrainte) est une fonction définie sur les interfaces du domaine de calcul, et qui nécessite le calcul préalable d'operateurs obtenus par la résolution de problèmes auxiliaires posés dans chaque sous-structure (on utilisera les équations intégrales de frontière dans les milieux élastiques, et une formulation variationnelle dans les milieux fluides). Une hypothèse supplémentaire d'axisymetrie permet une réduction du nombre de calculs par une expansion selon l'angle azimutal en mode de Fourier. Les résultats obtenus sont qualitativement et quantitativement satisfaisants

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24

Salvia, Marie-Virginie. "Développement d’outils analytiques et méthodologiques pour l’analyse et le suivi de composés vétérinaires et stéroïdes hormonaux à l’état de traces dans l’eau et le sol." Thesis, Lyon 1, 2013. http://www.theses.fr/2013LYO10036/document.

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De nombreux produits chimiques se retrouvent dispersés dans l'environnement avec des conséquences parfois néfastes pour les hommes et les écosystèmes. Parmi ces substances figurent les antibiotiques et les stéroïdes hormonaux. Peu de données sont disponibles quant à la présence et le devenir de ces substances dans l'environnement notamment pour le sol, par manque de méthodologies. Nous avons donc mis au point des procédures d'analyse de traces de ces contaminants émergents, dans l'eau et le sol. Nous avons développé des méthodes multi-résidus et inter-familles basées sur des analyses LCMS/ MS. Pour les échantillons aqueux, l'extraction est menée sur phase solide (SPE, OASIS HLB). Les MLQs sont comprises entre 0.09 et 34 ng/L. Pour la matrice solide, la procédure d'extraction est inspirée de la méthode appelée QuEChERS suivie d'une purification SPE. Elle a été validée et des MLQs entre 0.013 et 3 ng/g ont été atteintes. Les tétracyclines et les fluoroquinolones, ont été étudiées séparément car elles ont des propriétés physico-chimiques bien spécifiques les rendant difficiles à extraire correctement du sol avec une méthode inter-familles. La méthode développée sur la matrice sol a permis une étude statistique mettant en exergue l'impact de certains paramètres du sol sur les rendements d'extraction et les effets matrice. Les méthodes ont été appliquées à une étude en colonnes de sol pour obtenir des données sur le transfert, l'accumulation et la dégradation des composés dans le sol
Several chemical products are dispersed in the environment and the consequences can be sometimes harmful for humans and the ecosystems. Among these substances appear the antibiotics and the hormonal steroids. Nowadays, only few data are available on the presence and the fate of these substances in the environment in particular for solid matrices, mainly due to a lack of methodologies. Consequently, methods to analyze traces of « emergent » contaminants in water and soil were carried out. Therefore, multi-residues and inter-families procedures based on LC-MS/MS analysis were established. Concerning the aqueous samples, 23 analytes are extracted with the SPE technique (OASIS HLB). MLQs are between 0.09 and 34 ng/L. For the solid matrix, the extraction procedure of 31 compounds is inspired from the method called QuEChERS and followed by a purification step. This methodology was validated and MLQs between 0.013 and 3 ng/g were obtained. Two antibiotics families, tetracyclines and fluoroquinolones, were studied separately as they have specific physical/chemical properties and are therefore difficult to extract from soil with an inter-families method. Then, the method developed for the soil matrix allowed a statistic study which showed the impact of the soil parameters on the recoveries and matrix effects. Finally, the methodologies were applied to a soil column study which allowed obtaining data on the transfer, accumulation and degradation of the substances in soil

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25

Soares, Fábio Visnadi Prado. "Previsão de recalques por colapso de sapatas assentes em solo natural e compactado." Universidade Estadual Paulista (UNESP), 2018. http://hdl.handle.net/11449/152859.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
O comportamento dos solos não saturados é um tema amplamente estudado, tanto por meio de ensaios de laboratório quanto de campo. Fenômenos como o colapso dos solos são relativamente bem explicados pelos modelos elastoplásticos existentes, dos quais o Modelo Básico de Barcelona é um dos mais utilizados e difundidos no meio acadêmico. Apesar dos avanços obtidos, ainda existe certa escassez de estudos que comparem o comportamento previsto por tais modelos a resultados de situações reais de engenharia. Esta pesquisa teve como objetivo simular numericamente resultados de recalques devidos a carregamentos e inundação de provas de carga em placa e de protótipos de sapata construídas sobre solo natural e compactado em cava. Com os resultados buscou-se analisar a eficiência da técnica de compactação para mitigar o problema do colapso do solo. Para isso, ensaios de compressão triaxial e edométricos com sucção controlada, bem como ensaios de curva de retenção e condutividade hidráulica foram realizados para determinação dos parâmetros constitutivos hidráulicos e mecânicos do solo natural e compactado que foram utilizados no programa Code_Bright para simulação numérica dos resultados de campo. Os resultados demonstraram a capacidade do modelo em reproduzir o comportamento do solo no campo. Demonstraram também que o uso da compactação do solo que preconiza compactar em cava uma camada de espessura equivalente à largura da sapata é viável para redução da colapsibilidade, mas depende do nível das tensões atuantes nas fundações e da tolerância aos recalques. Tensões propagadas para a camada de solo natural superiores à tensão de pré-adensamento do solo natural saturado provocarão recalques por colapso quando o solo for umedecido.
The behaviour of unsaturated soils is a widely studied theme around the world, both by utilising laboratory and field tests. Phenomena like soil collapsibility are relatively well explained by the existing elastoplastic models, among which the Barcelona Basic Model is the most widely used in the academic field. Despite the recent advances, there is still a scarcity of papers that compare the behaviour predicted by constitutive models and results of real engineering problems. This research aims to numerically simulate the results of settlement due to loading and wetting of load tests built both on undisturbed and compacted soil. The results were analysed in order to study the efficacy of the soil compaction technique in mitigating soil collapse. Suction controlled triaxial compression and oedometer tests, as well as soil water retention curve and hydraulic conductivity experiments were conducted to determine the hydraulic and mechanic parameters used in the software Code_Bright to numerically simulate field results. The results highlight the capability of the model in reproducing the analysed field behaviour. They also show that the technique that involves compaction of the soil equal to the footing’s width is viable to reduce its collapsibility, but its efficacy will also depend on the tensions applied on the foundation and on the tolerable settlement values. Tensions that are propagated to the natural soil layer that are higher than its preconsolidation stress will cause collapse settlements and wetted.

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26

Vitale, Quentin. "Modélisation et conception d'antennes radar large bande pour la cartographie de la teneur en eau volumique des sols agricoles." Thesis, Paris 6, 2014. http://www.theses.fr/2014PA066189/document.

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Le travail de recherche présenté dans ce mémoire de thèse s'inscrit dans le cadre d'un projet de développement d'un outil radar pour la cartographie de la teneur en eau des sols agricoles et se consacre plus particulièrement à la conception de deux prototypes d'antennes radar large bande. Deux prototypes d'antennes ont ainsi été conçus de manière numérique sur la base d'un code de simulation électromagnétique en trois dimensions basé sur la méthode des différences finies dans le domaine temporel (FDTD) pour la résolution des équations de Maxwell. Les prototypes ont été conçus avec comme ligne directrice un encombrement minimum (format A4) et une largeur de bande maximum sur la gamme 100 MHz - 1 GHz (dans l'air). Afin d'étudier apriori le comportement de ces prototypes en présence de sols, une étude numérique a été réalisée en représentant les sols par des demi-espaces infinis. Cette étude numérique se base sur l'évolution du coefficient de réflexion des prototypes dans le domaine fréquentiel (s11). Pour s'approcher au mieux des conditions de terrain, l'effet d'un contact non idéal entre l'antenne et le sol (représentée par une élévation de l'antenne) ainsi que celui de la rugosité du sol (représenté par des surfaces en tôle ondulée et en boîtes d'oeufs) ont été investigués. Sur la base de cette étude numérique, deux prototypes d'antennes (une antenne de type bow-tie et une de type dipôle elliptique) ont été fabriqués et testés en laboratoire et sur le terrain. Les premiers tests en laboratoire ont permis : (i) de vérifier la bonne cohérence entre mesure de s11 en milieu contrôlé et simulation FDTD précise de l'antenne (i.e. prenant en compte tous ses éléments constitutifs), (ii) une calibration en champ lointain et en champ proche de l'antenne permettant l'utilisation d'un modèle analytique pour simuler le s11 de l'antenne en présence d'un sol, (iii) une première estimation de la permittivité diélectrique d'un sol simple (sable) par les deux types de modélisation (FDTD et analytique). Enfin, les prototypes d'antennes ont été testés sur le terrain afin de vérifier leur comportement lors de mesures in situ. Ces tests montrent un fort impact (bruit) des câbles coaxiaux utilisés lors des mesures (notamment à haute fréquence), ainsi qu'une bonne sensibilité du dispositif aux contrastes de permittivité diélectrique
The research work submitted in this PhD dissertation is part of research project which aims to develop a new tool for mapping the soil water content in agricultural context with ground penetrating radar technology. The scope of this particular work is the development of two prototypes of wideband radar antennae. Hence, two prototypes of antennae have been numerically designed based on a 3D finite-difference in time-domain (FDTD) electromagnetic solver of Maxwell's equations. The guiding principles that have been followed during the design are mainly a small size antenna (A4 format) and achieving the wider bandwidth possible in the frequency range 100 MHz - 1 GHz (in the air). In order to study the behavior of our prototypes when put in presence of soils, we conducted a numerical study representing the soils by half-spaces. This numerical study was based on the analysis of the antennae reflection coefficient in the frequency domain (or return loss coefficient s11). To be as close as possible to field conditions, the effect of a non ideal contact between the antenna and the soil (represented by a small elevation of the antenna) as well as the effect of soil surface rugosity (represented by corrugated iron-like and eggbox-like surface) have been investigated. Based on this numerical study, two prototypes of antennae (one bow-tie-like and on elliptical dipole) have been physically built and tested in both lab and field conditions. The test in lab condition enabled us to: (i) check the similarity between measured s11 in a controlled environment and corresponding FDTD simulation of the antenna including all antenna parts, (ii) calibrate the antenna in both far field and near field conditions which enabled the use of an analytical model to simulated the antenna s11 in presence of soil, (iii) estimate the dielectric permittivity of a sand sample using both FDTD and analytical simulations. Finally, the prototypes were tested in field condition in order to verify their behavior for in situ measurements. These tests show that using unshielded coaxial cable has a very important impact on the data (noise) and that the prototypes demonstrate a good sensitivity to dielectric permittivity contrasts

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27

Fares, Reine. "Techniques de modélisation pour la conception des bâtiments parasismiques en tenant compte de l’interaction sol-structure." Thesis, Université Côte d'Azur (ComUE), 2018. http://www.theses.fr/2018AZUR4103/document.

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La conception des bâtiments selon le code sismique européen ne prend pas en compte les effets de l'interaction sol-structure (ISS). L'objectif de cette recherche est de proposer une technique de modélisation pour prendre en compte l’ISS et l'interaction structure-sol-structure (ISSS). L'approche de propagation unidirectionnelle d’une onde à trois composantes (1D-3C) est adoptée pour résoudre la réponse dynamique du sol. La technique de modélisation de propagation unidirectionnelle d'une onde à trois composantes est étendue pour des analyses d'ISS et ISSS. Un sol tridimensionnel (3D) est modélisé jusqu'à une profondeur fixée, où la réponse du sol est influencée par l’ISS et l’ISSS, et un modèle de sol 1-D est adopté pour les couches de sol plus profondes, jusqu'à l'interface sol-substrat. Le profil de sol en T est assemblé avec une ou plusieurs structures 3-D de type poteaux-poutres, à l’aide d’un modèle par éléments finis, pour prendre en compte, respectivement, l’ISS et l’ISSS dans la conception de bâtiments. La technique de modélisation 1DT-3C proposée est utilisée pour étudier les effets d’ISS et analyser l'influence d'un bâtiment proche (l'analyse d’ISSS), dans la réponse sismique des structures poteaux-poutres. Une analyse paramétrique de la réponse sismique des bâtiments en béton armé est développée et discutée pour identifier les paramètres clé du phénomène d’ISS, influençant la réponse structurelle, à introduire dans la conception de bâtiments résistants aux séismes. La variation de l'accélération maximale en haut du bâtiment avec le rapport de fréquence bâtiment / sol est tracée pour plusieurs bâtiments, chargés par un mouvement à bande étroite, excitant leur fréquence fondamentale. Dans le cas de sols et de structures à comportement linéaire, une tendance similaire est obtenue pour différents bâtiments. Cela suggère l'introduction d'un coefficient correcteur du spectre de réponse de dimensionnement pour prendre en compte l’ISS. L'analyse paramétrique est répétée en introduisant l'effet de la non-linéarité du sol et du béton armé. La réponse sismique d'un bâtiment en béton armé est estimée en tenant compte de l'effet d'un bâtiment voisin, pour un sol et des structures à comportement linéaire, dans les deux cas de charge sismique à bande étroite excitant la fréquence fondamentale du bâtiment cible et du bâtiment voisin. Cette approche permet une analyse efficace de l'interaction structure-sol-structure pour la pratique de l'ingénierie afin d'inspirer la conception d'outils pour la réduction du risque sismique et l'organisation urbaine
Building design according to European seismic code does not consider the effects of soil-structure interaction (SSI). The objective of this research is to propose a modeling technique for SSI and Structure-Soil-Structure Interaction (SSSI) analysis. The one-directional three-component (1D-3C) wave propagation approach is adopted to solve the dynamic soil response. The one-directional three-component wave propagation model is extended for SSI and SSSI analysis. A three-dimensional (3-D) soil is modeled until a fixed depth, where the soil response is influenced by SSI and SSSI, and a 1-D soil model is adopted for deeper soil layers until the soil-bedrock interface. The T-soil profile is assembled with one or more 3-D frame structures, in a finite element scheme, to consider, respectively, SSI and SSSI in building design. The proposed 1DT-3C modeling technique is used to investigate SSI effects and to analyze the influence of a nearby building (SSSI analysis), in the seismic response of frame structures. A parametric analysis of the seismic response of reinforced concrete (RC) buildings is developed and discussed to identify the key parameters of SSI phenomenon, influencing the structural response, to be introduced in earthquake resistant building design. The variation of peak acceleration at the building top with the building to soil frequency ratio is plotted for several buildings, loaded by a narrow-band motion exciting their fundamental frequency. In the case of linear behaving soil and structure, a similar trend is obtained for different buildings. This suggests the introduction of a corrective coefficient of the design response spectrum to take into account SSI. The parametric analysis is repeated introducing the effect of nonlinear behaving soil and RC. The seismic response of a RC building is estimated taking into account the effect of a nearby building, for linear behaving soil and structures, in both cases of narrow-band seismic loading exciting the fundamental frequency of the target and nearby building. This approach allows an easy analysis of structure-soil-structure interaction for engineering practice to inspire the design of seismic risk mitigation tools and urban organization

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Lebeau, Benoit. "Les tensiometres pour l'irrigation en milieu tourbeaux." Thesis, McGill University, 1995. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=22754.

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Water management for the irrigation of containerized production remains a task reserved to a highly qualified personnel. Without proper instruments to determine the actual water needs, nursery crops can face growth losses of 20 to 30%.
Reviewing the different methods that are used in field production, tensiometer have shown the greatest potential of adaptation to potted plants.
Tests on the utilization of tensiometer were realized on two peat-vermiculite substrates, using two types of porous cup (1 bat--standard flow and 1 bar--high flow). The instruments were tested while permanently fixed in the growing medium, and temporarily fixed for three hours in the growing medium.
The results show that the instruments give excellent measurements for normal condition of growth, requiring saturation level between 50 and 100%, and that for both mode of operation.
Preferably, the choice of the instrument should be based on the hydraulic characteristics of the substrate. Little difference has been found using both instrument in the substrate 1, but in substrate 2 however, the high flow porous cups have given better response. The high flow cups have higher porosity and bigger pores that suit better substrate 2, which is made of coarser particles.

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Svay, Angkeara. "Modélisation de la Variabilité Spatiale du Champ Sismique pour les Etudes d’Interaction Sol-Structure." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLC016/document.

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Dans les analyses d'interaction sol-structure (ISS), la pratique commune en génie civil est de considérer un mouvement uniforme du champ libre à tous les points situés à la surface du sol. Néanmoins, cette considération n'est pas tout à fait réaliste parce que les signaux sismiques sont spatialement différents grâce à l'effet de passage d'ondes, à l'effet de site et aussi aux dispersions et réflexions des ondes qui propagent dans des milieux hétérogènes aléatoires ("incohérence pure"). Ainsi, pour répondre aux problèmes de sécurité des bâtiments et équipements, il est important de faire une analyse d'interaction sol-structure dans la manière plus réaliste. Cela peut être acquis par prendre en compte la variabilité spatiale du champ sismique dans les études d'ISS. Un grand nombre d'études dans la littérature montrent que la prise en compte de la variabilité spatiale du champ sismique dans les études d'ISS peut avoir des effets importants sur la réponse de structures. L'incohérence spatiale du champ sismique due aux dispersions et réflexions des ondes (incohérence pure) peut généralement être modélisée pour ce genre d'études dans le cadre probabiliste par une fonction de cohérence. Le but principal des études réalisées dans cette thèse de doctorat est de construire une description stochastique de la variabilité spatiale du champ sismique par un modèle de cohérence. Ce modèle devrait avoir une relation avec les propriétés physiques et statistiques de milieux considérés. En s'appuyant sur les analyses théoriques de la propagation des ondes sismiques dans des milieux hétérogènes aléatoires, les analyses des données expérimentales obtenues par des enregistrements sur des sites sismiques, ainsi que sur les modélisations numériques de propagation des ondes sismiques dans des milieux hétérogènes aléatoires, un modèle de cohérence est validé dans le cadre des études de cette thèse de doctorat pour représenter la variabilité spatiale du champ sismique dans les études d'interaction sol-structure. L'influence de la variabilité spatiale du champ sismique sur la réponse de structure est également analysée
In seismic soil-structure interaction studies (SSI), the common practice in Civil Engineering is to consider a uniform movement of free field at any point on the ground surface. However, that assumption is not completely realistic since the seismic ground motions can vary spatially due to wave passage effects, dispersions and reflections of wave propagating in the random heterogeneous media "pure incoherence" and site effects. Therefore, in order to increase the security of buildings and equipment, it is important to do an analysis of seismic soil-structure interactions in the most realistic way. This can be achieved by taking into account the spatial variability of seismic ground motions. Several studies in the literature show that taking into account the spatial variability of seismic ground motions in SSI analyses can have remarkable effects on the structural responses. The spatial incoherence of seismic ground motions due to dispersions and reflections of wave "pure incoherence" can generally be modelled in such analysis by a "coherency function" in frequency domain. The principal goal of this Ph.D thesis is to construct a stochastic description of spatial variability of seismic ground motions by means of coherency functions. Accurately, it aims to propose a parametrical coherency model of spatial variability of seismic ground motions. This later should be related to some physical and statistical properties of the soil at the application sites so that it can be applied in any types of sites. Based on theoretical considerations on coherency of seismic wave propagation in random heterogeneous media, on experimental data analyses, and on numerical modelling of seismic wave propagation in random heterogeneous media, a coherency model is validated and proposed for the analyses of soil-structure interactions. The influence of spatial variability of seismic ground motions on the structural responses are also pointed out by using the validated coherency model

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Do, Quoc Viet. "Impacts des mouvements de terrains sur une structure type "maison individuelle" : modélisation de l'interaction sol-structure pour l'évaluation de la vulnérabilité du bâti." Thesis, Paris Est, 2011. http://www.theses.fr/2011PEST1075.

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Dans ce travail, les risques naturels considérés concernent des mouvements de terrains qui résultent de deux phénomènes principaux : retrait et gonflement des sols argileux et l'affaissement à grand rayon lié à la présence des cavités souterraines. Ceux-ci provoquent des tassements différentiels du sol qui génèrent des désordres sur les constructions environnantes : dégâts et fissuration des murs porteurs en maçonnerie, particulièrement aux angles du bâti. Ces dégradations structurales induisent des conséquences économiques importantes dans le cas des maisons individuelles ; elles résultent d'un manque de résistance des maçonneries, du peu de raideur de leur système de fondation et du peu d'efficacité de leur système de contreventement. Cette recherche a pour objectif d'analyser la vulnérabilité du bâti et de proposer des méthodes de renforcement pour les constructions existantes ainsi que des recommandations de dimensionnement pour les constructions. Ces questions nécessitent une connaissance approfondie du phénomène des mouvements des terrains et des modalités de transfert de ces actions à une structure. Pour y répondre, quatre étapes principales ont été effectuées : une étude bibliographique, une analyse de l'interaction sol-structure, un développement d'une justification d'endommagement et d'une méthode de renforcement ou de dimensionnement ainsi qu'une analyse probabiliste des risques. L'étude bibliographique avec des analyses fonctionnelles et statistiques, d'abord, propose un profil de la maison sensible à l'aléa naturel et des cas typiques des désordres sur la construction. Le développement des modélisations par éléments finis ensuite permet d'étudier les phénomènes d'interaction sol-structure. L'analyse de l'interaction sol - structure, au moyen de modélisations par éléments finis, permet d'obtenir des sollicitations dans la maçonnerie. D'abord, des modèles analytique et numérique simplifiés ont été développés pour modéliser des structures simples telles une semelle filante, un système de semelles d'une fondation filante ou un mur en maçonnerie sur un sol élastique de type Winkler ou Boussinesq. Ensuite, des modélisations de structures plus complexes avec tous les éléments du bâti ont été effectuées en développant un code aux éléments finis particulier qui a permis de calculer des bâtiments en maçonnerie sur un sol de type Pasternak. En vue de développer une justification d'endommagement ainsi qu'une méthode de renforcement et de dimensionnement adaptée pour risque «mouvement de terrains », les travaux de recherche focalisent sur la distribution des sollicitations obtenues par des modélisations et analysent les domaines de validité de la démarche proposée par les Eurocodes EC6 et EC8 pour les murs de contreventement en maçonnerie confinée (chainée) ou armée. L'analyse probabiliste des risques, couplant les modèles aux éléments finis développés avec la méthode des simulations de Monte-Carlo, a permis d'étudier la vulnérabilité des maisons individuelles selon les caractéristiques structurales représentatives du bâti existant, dans les régions les plus touchées par les mouvements de terrains. Les résultats de cette analyse ont été unifiés, au sein d'une méthodologie globale de l'évaluation de la vulnérabilité de structures, à l'usage, d'une part, des pouvoirs publics dans l'établissement de cartographies SIG des risques, et d'autre part de la capacité des procédés de renforcement à l'usage des industries
In the present work, the considered natural hazards concern to ground movements resulting from two main phenomena : shrinkage and swelling of clay soils and ground subsidence due to the presence of underground cavities. These phenomena cause differential ground settlements which generate disorders on the structures erected in their neighborhood : damage and cracking of masonry load-bearing walls, especially at the building corners. These structural degradations cause important economic consequences and losses in the case of dwelling houses. These damages result from a lack of masonry resistance or a small stiffness of the foundation system as well as a limited effectiveness of bracing system.This research aims to analyze the vulnerability of buildings and to propose a reinforcement method for the existing constructions as well as design recommendations for structures. These topics require a thorough understanding of the ground movements phenomenon and their transfer as actions on a structure. For this purpose, four main steps were performed : a literature review, an analysis of soil-structure interaction, a development of a damage justification and a method for reinforcement or design, as well as a probabilistic analysis of risk.The literature review with functional and statistical analysis, as a first step, provides a profile of the house susceptible to natural hazard effects and typical cases of building disturbances. The development of finite element method is therefore considered in order to study soil-structure interaction.The analysis of the soil-structure interaction using finite element modeling provides stresses in the masonry. First, simplified analytical and numerical models have been developed for simple structures such as a strip footing, a system of strips foundation or a masonry wall lying on elastic soil (Winkler or Boussinesq). Afterwards, modeling of more complex structures with the whole building elements was made by developing a particular finite element code that allowed the calculation of masonry buildings on a Pasternak soil. To develop a damage justification as well as the reinforcement and design building methods suitable for risk of “ground movements”, this work focuses on the stresses distribution obtained by numerical models and analyzes the validity domain of the approach proposed by Eurocodes EC6 and EC8 for confined masonry or reinforced masonry. By coupling the developed finite element models with the Monte-Carlo method, the probabilistic analysis of risk allows to study the vulnerability of dwelling houses having representative structural characteristics of existing buildings, erected in areas that are the most affected by ground movements. The results of this analysis have been unified into a global methodology for assessing the vulnerability of structures. This methodology is used, in one hand, for the development of GIS mapping of risks and, in other hand, for the reinforcement processes

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Daugé, Frédéric. "Architectures innovantes pour les transistors SOI." Grenoble INPG, 2005. http://www.theses.fr/2005INPG0044.

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"L'objectif de ce travail est l'étude des fransistors MOS/SOI à film de silicium ultra-mince avec une architecture multi-grille. Cette étude comporte une caractérisation électrique fine et une modélisation analytique réalisée à l'aide d'un nouveau programme développé lors de cette thèse, " CAPS ". Ce programme, basé sur le équations couplées Poisson-Schrodinger, permet, entre autres, la prise en compte des effets du confinement quantique et leur impact multidimensionnel. Une version modifiée de la méthode de Hänsch est proposée et l'intégration dans CAPS de la non parabolicité des bandes montre la nécessité de considérer cet effet pour des films de Si inférieurs à 5nm. D'autre part, une étude détaillée sur les effets de couplage des interfaces dans les transistors MOS/SOI complètement désertès et double-grille est réalisée. L'impact du désalignement des grilles dans les transistors DG est également analysé. Enfin, grâce à une nouvelle méthode d'extraction, les propriétés de conduction des différents canaux des transistors FinFETs sont comparées. "
The aim of this work is the study of ultra-thin silicon film MOS/SOI transistors with multi-gate architecture. This study includes a thorough electrical characterization and an analytical modeling carried out using a new program, developed during this work, "CAPES". This program, based on the Poisson-Schrodinger coupling equations, takes into account the quantum confinement effect and their multidimensional impact. A modified version of Hänsch method is proposed and the integration in CAPES of the non bands parabolicity shows the need for considering this effect for Si films thinner than 5nm. Ln addition, a detailed study on the interfaces coupling effects in fully-depleted and double-gate MOS/SOI transistors is achieved. The impact of the gate misalignement in DG devices is also analysed Finally, thanks to a new extraction method, the transport properties of the various channels of the FinFETs transistors are compared

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32

Lyu, Han. "EFFECTS OF CLIMATE AND GEOCHEMISTRY ON SECONDARY MINERAL DISTRIBUTION AND SOIL ORGANIC CARBON POOLS IN TROPICAL VOLCANIC REGIONS." Doctoral thesis, Kyoto University, 2021. http://hdl.handle.net/2433/263813.

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33

Boin, Elisa Aurora Santana Ferreira 1986. "Remediação de solo contaminado por chumbo por imobilização induzida por fosfato na região de Apiaí, Vale do Ribeira (SP)." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/287088.

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Orientador: Bernardino Ribeiro de Figueiredo
Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Geociências
Made available in DSpace on 2018-08-21T05:25:31Z (GMT). No. of bitstreams: 1 Boin_ElisaAuroraSantanaFerreira_M.pdf: 3244830 bytes, checksum: a92b7a7798b0192e575c0b345bbd5a3b (MD5) Previous issue date: 2012
Resumo: A exposição humana ao chumbo pode ser reduzida a partir de um controle de disponibilidade e mobilidade do mesmo por meio da aplicação de fertilizante fosfatado, induzindo a adsorção do chumbo e a formação de compostos insolúveis como a piromorfita. Os objetivos desta pesquisa foram caracterizar, física, química e mineralogicamente, o solo e os materiais fosfatados para otimização do tratamento de remediação e, a partir destas caracterizações, avaliar um método de remediação de solo adaptado para a região do CIEM/CPRM, em Apiaí (SP), baseado na imobilização do chumbo por fosfato. Nos experimentos em bancada foram analisados dois tipos de material: fosfato diamônico (DAP), na razão molar (P:Pb) 1:5, e rocha fosfática, na razão molar (P:Pb) 3:5, além da granulometria dos materiais fosfatados (comercial e moída) e o tempo de tratamento (3, 6 e 9 meses) em solo com 3,5% de chumbo. Experimentos in situ fora realizados em 3 locais com diferentes concentrações de chumbo (1204 mg.kg-1, 94 mg.kg-1 e 5191 mg.kg-1) utilizando rocha fosfática na razão molar (P:Pb) 4:1 e analisados em em períodos de 3 e 6 meses. Foram realizadas análises de concentração de Pb, Zn, Cu, As e Cd na fração solúvel em solo e em extrato parcial mediante ataque com acetato de amônio 1M a pH 4,5. O DAP não se mostrou um bom imobilizador de Pb pois teve a eficácia diminuída com o tempo e induziu a redução do pH, liberando Pb e outros elementos-traço para as frações estudadas nesta pesquisa. A aplicação de rocha fosfática elevou o pH e reduziu da concentração de Pb e outros elementos-traço: 37% na fração solúvel em solo e 20% no extrato parcial de solo após 9 meses de tratamento. Além disso, não foram observadas alterações nas concentrações de outros elementos-traço. Nestes ensaios não houve diferenças expressivas nos resultados em relação à granulometria da rocha fosfática. Nos experimentos in situ a aplicação de rocha fosfática resultou na imobilização de até 99% do chumbo disponível na fração solúvel em solo e de até 81% do chumbo disponível em extrato parcial e reduziu a concentração de outros elementos-traço nestas frações. Foi observada a ocorrência de piromorfita no solo tratado, porém os principais processos de imobilização do chumbo foram a adsorção por minerais de argila, óxidos e na superfície da rocha fosfática. A utilização de rocha fosfática, como imobilizador de chumbo, se mostrou eficiente para remediação do solo do CIEM/CPRM em Apiaí, independente da concentração de Pb. É recomendado que o planejamento de remediação do local contemple as seguintes ações: remover e isolar a escória em cápsulas de concreto no subsolo e cobri-las com solo não contaminado; revolver o solo contaminado com rocha fosfática (4:1 - P:Pb), cobrindo esses locais com uma nova camada de solo não contaminado; cobrir toda a área com grama e plantas e monitorar a qualidade do solo e a da água, visto que há possibilidade de lixiviação de outros elementos-traço como As e Cd
Abstract: Human exposure to lead can be reduced with a control of availability and mobility of lead through application of phosphatic fertilizers, inducing adsorption of lead and formation of insoluble compounds like pyromorphite. The goals of this research were to characterize physically, chemically and mineralogically the soil and the phosphate materials to optimize the remediation treatment based on immobilization of lead by phosphate in order to adapt a soil remediation method to the region studied. In the laboratorial experiments two types of material were analyzed: diammonium phosphate (DAP) at 1:5 molar ratio (P:Pb) and phosphate rock at 3:5 molar ratio (P:Pb), in addition to phosphate materials particle size (ungrounded and grounded) and the time of treatment (3, 6 and 9 months) in soil with 3.5% of lead contamination. In-situ experiments were carried out in 3 locations with different concentrations of lead (1,204 mg.kg-1, 94 mg.kg-1and 5,191mg.kg-1) using phosphate rock at 4:1 molar ratio (P:Pb) and collecting data at 3 and 6 months. Pb, Zn, Cu, and Cd concentration analyses were carried out in water soluble fraction and partial extract of ammonium acetate at pH 4.5 1M. DAP was not effective as lead immobilizer as diminished effectiveness over time and induces pH decrease, releasing Pb and other metals to the fractions here studied. Phosphate rock increased pH and reduced lead and other metal concentrations in the water soluble fraction (37% reduction of metal after 9 months of treatment) and partial extract (20% reduction after 9 months of treatment). Besides, it did not alter the concentrations of metals in this fraction and increased its performance over time. There were no expressive alterations in the results when comparing phosphate rock particle sizes. In the experiments in-situ the application of phosphate rock immobilized up to 99% of the lead available in soluble fraction and up to 81% of the lead available in partial extract. It also reduced other metals concentrations in these fractions. Although formation of pyromorphite took place, the main mechanism was lead adsorption by clay minerals, oxides and the surface of the phosphate rock. The use of phosphate rock as lead immobilizer showed to be efficient for soil remediation in the region studied independently of the lead concentration. It is recommended that the site remediation planning contemplate the following actions: removal and isolation of the slag in concrete capsules in the underground covering them with uncontaminated soil; mixing contaminated soil with phosphate rock (4:1 - P:Pb) and depositing a new layer of uncontaminated soil on these spots; replanting all the area with grass and plants and monitoring soil and water quality, seeing that there is a possibility of lixiviation of other trace elements such as As and Cd
Mestrado
Geologia e Recursos Naturais
Mestre em Geociências

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Ellili, Yosra. "Evaluation biophysique des services écosystémiques des sols cultivés - Adaptation de l’information pédologique pour la modélisation dynamique du fonctionnement des sols." Thesis, Rennes, Agrocampus Ouest, 2019. http://www.theses.fr/2019NSARD087.

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Les sols rendent de nombreux services écosystémiques essentiels au maintien de la vie planétaire. Toutefois, ils sont soumis à une pression croissante pour satisfaire les demandes d’une population croissante en matière de production alimentaire et énergétique. En vue d’une meilleure gestion, des outils d’aide à la décision intégrant la diversité des sols sont nécessaires pour évaluer l’impact des activités anthropiques sur l’évolution des sols. Cette thèse se focalise notamment sur le développement d’une méthodologie de mise à disposition de l’information pédologique contenue dans les bases de données existantes (1/250 000) par une approche de désagrégation spatiale en vue de l’évaluation de six services écosystémiques des sols cultivés.Le couplage des données locales, des données spatialisées avec une précision connue et de la modélisation dynamique permet en premier temps de produire des indicateurs de services écosystémiques des sols cultivés et en deuxième temps d’évaluer l’effet de la source de l’information pédologique sur les services écosystémiques instruits. Les résultats obtenus montrent l’apport de la cartographie numérique pour la production de l’information pédologique nécessaire à l’évaluation des services écosystémiques. Ils permettent également d’identifier les voix d’amélioration possibles pour proposer une voie hybride d’évaluation des services écosystémiques couplant la modélisation et les proxies. Il s’agit ainsi de promouvoir la prise en compte des sols dans des stratégies de gestion durable et de planification territoriale
Soils provide many ecosystem services essential to sustain human life and socio-economic development. However, soils are subjected to increasing pressure from current activities, including intensive land use to satisfy demands of a growing population for food and energy. To improve soil management, decision-support tools that consider soil diversity are required to assess impacts of human activities on soil dynamics. The objective of this study was to develop and validate a methodology to enhance existing pedological information (1: 250,000) using spatial disaggregation technique in order to estimate in space soil ecosystem services.By combining field observations, disaggregated soil data with known accuracy and dynamic modelling, six soil ecosystem services indicators were firstly assessed, to be then used to evaluate the sensitivity of estimated soil ecosystem services to the source of soil information. The main results highlight the contribution of digital mapping to produce relevant pedological information for assessing soil ecosystem services from cultivated soils. Future research must be performed to improve pedological information availability and soil ecosystem services assessment procedure by coupling dynamic coupling and proxies. Overall, this work emphasize the need to produce soils consideration in sustainable management strategies and territorial planning

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Dresler, Johanna. "Préformulation d'un soin anti-tâche pour la peau." Paris 5, 1999. http://www.theses.fr/1999PA05P135.

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Tiberj, Antoine. "Matériau SOI pour capteur à effet Hall." Montpellier 2, 2003. http://www.theses.fr/2003MON20012.

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Dainese, Roberta. "L'utilisation du tensiomètre de grande capacité dans le cadre d'un système intégré de surveillance du continuum sol-plante pour les applications géotechniques." Thesis, Montpellier, 2019. http://www.theses.fr/2019MONTG094.

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La stabilité des pentes, des berges et des structures de terre est déterminée par la force de cisaillement que le sol peut mobiliser. La portion supérieure du profil du sol (zone vadose) ainsi que les structures de terre sont généralement partiellement saturées et la force de cisaillement est affectée par la pression de l'eau interstitielle (négative) et le degré de saturation. Quand la quantité d’eau dans le sol est réduite, la pression d’eau interstitielle est épuisée, ce qui augmente la force de cisaillement. L’extraction d’eau du sol peut ainsi être vue comme une technique permettant de renforcer le sol et d’en améliorer sa stabilité.Une approche naturelle pour extraire l’eau du sol, consiste à exploiter la demande évaporative de l’atmosphère. Le problème de la transpiration des plantes est complexe, car il dépend d’un couplage entre le sol, les plantes et l'atmosphère. Cependant, il présente une opportunité de contrôler activement le procédé d’extraction d’eau par la sélection adéquate d’espèces couvrant la surface du sol. Il en résulte que la végétation peut potentiellement être ‘conçue’ pour stabiliser les structures géotechniques.Ce travail propose un cadre expérimental pour l'étude de l'efficacité de la végétation à extraire l’eau du sol par transpiration, dont la méthodologie générale se base sur la comparaison entre la transpiration (depuis un sol végétal) et l’évaporation (depuis un sol nu), tant en laboratoire que dans le milieu naturel. L’étude expérimentale du processus de transpiration requiert ainsi le suivi continu des flux d’eau sol-plante-atmosphère. Une nouvelle méthode a été développée pour suivre la pression d’eau du xylème : Le tensiomètre à haute-capacité (HCT) a été appliquée sur le xylème végétal pour mesurer la pression d’eau du xylème. Cette méthode a été validée en comparaison avec les méthodes usuelles utilisées en science des plantes. La nouvelle procédure est une évolution majeure dans l’étude des flux parce que il permet l’utilisation d’un seul instrument pour suivre la totalité de la continuité sol-plante.Le processus de transpiration a tout d’abord été étudié en laboratoire où deux colonnes de sol ont été développées, une avec végétation et l’autre laissée avec un sol nu pour comparaison de la transpiration et évaporation sous conditions atmosphérique équivalentes. Les colonnes étaient instrumentées pour suivre la quantité d’eau et la pression négative d’eau interstitielle et le taux de transpiration.Le résultat direct de ces tests en laboratoire est que la végétation n’a pas toujours un effet bénéfique. Dans le régime énergie-limitée, la combinaison de la résistance aérodynamique et de la résistance du canopée peut avoir une influence en faveur du sol nu ou végétal en fonction du type de végétation. Ceci a été démontré par les expériences en laboratoire. Dans le régime eau-limitée, l’effet de la végétation est toujours bénéfique car le mode d’extraction d’eau est différent. Ceci est apparent dans le temps que met le processus de transpiration à entrer en régime d’eau-limitée, qui est plus long dans un sol végétal que dans un sol nu.Les effets hydrauliques de la végétation ont finalement été étudiés en milieu naturel dans une plantation de peupliers à Montpellier, France. Le profil de contenu en eau a été suivi pendant toute la saison sèche et la période de pluie suivante dans une zone peuplée de peuplier ainsi que dans le champ voisin labouré (virtuellement nu). Le cadre conceptuel développé sur la base d’expériences en laboratoire a été ainsi fondamental pour permettre l’interprétation des résultats obtenus en milieu naturel, et montrer dans quel régime la végétation a un effet bénéfique dans ce cas précis.Pour conclure, cette dissertation a permis de démontrer les effets de la transpiration des plantes dans l’extraction d’eau du sol, grâce à quoi l'amélioration la stabilité des pentes et des structures terrestres peut désormais être évaluée sur la base de mesures quantitatives
The stability of slopes, embankments and earth structures is determined by the shear strength that the soil can mobilise. The upper portion of the soil profile (vadose zone) and the earth structures are usually partially saturated and the shear strength is affected by the (negative) pore-water pressure and the degree of saturation. If the amount of water in the soil is reduced, pore-water pressure is depleted and the shear strength increases. Soil water removal can therefore be viewed as a technique to strengthen the ground and enhance stability.A natural, low-cost, and low-carbon approach to remove soil water consists in exploiting the evaporative demand of the atmosphere. Evaporation from bare soil is well studied, but it is difficult to ‘engineer’ the process to enhance soil water removal. The problem of plant transpiration is complex as it involves the coupling between soil, plant and atmosphere. However, it offers the chance to control actively the process of water removal if adequate species are selected to cover the ground surface. As a result, vegetation can potentially be ‘engineered’ to stabilise geotechnical structures.This work has developed an experimental framework to investigate the effectiveness of vegetation in removing soil water by transpiration and the overall methodology has been designed around the comparison between transpiration (from vegetated soil) and evaporation (from bare soil), both in the laboratory and in the field. Experimental investigation into transpiration processes therefore requires the monitoring of the water flow through the Soil-Plant-Atmosphere Continuum.A novel technique was developed to monitor xylem water pressure. The High-Capacity Tensiometer (HCT), developed by geotechnical researchers, was tested on the plant to measure the xylem water pressure. This technique was validated via comparison with techniques routinely used in plant science. The novel procedure for the measurement of negative xylem water pressure is a step change in the study of continuous flow along the soil-plant system, especially in the geotechnical field. This allows the use of a single instrument to monitor the entire soil-plant continuum.The transpiration process was then first investigated in the laboratory. Two soil columns were developed, one vegetated and one left bare to compare the transpiration and evaporation respectively under the same atmospheric conditions. The columns were instrumented to monitor the water content, (negative) pore-water pressure in the soil respectively and the transpiration rate.The straightforward outcome from these laboratory tests is that vegetation does not have necessarily a beneficial effect. In the energy limited regime, the combination of the aerodynamic and canopy resistances can play either in favour of the bare or the vegetated soils depending on the vegetation type. In the water-limited regime, the effect of vegetation is always beneficial due to the different mode of water extraction. This is reflected in the time at which the transpiration enters the water limited regime, which is definitely longer in the vegetated soil than the bare one. Both aspects have been clearly demonstrated in the laboratory experiments.The hydrological effects of vegetation where finally investigated in the field in a poplar plantation in Montpellier, France. The water content profile was monitored throughout the dry season and the following rainy period in a poplar vegetated area as well as in the adjacent ploughed (virtually bare) field. The conceptual framework developed on the basis of the laboratory experiments was therefore key to interpret the field data and show in which regime the vegetation has beneficial effects in this specific case.In conclusion, this dissertation has shown how the effects of plant transpiration in removing soils water and, hence, enhancing the stability of slopes and earth structures can be assessed based on quantitative measurements

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Dorji, Tshering. "Soil organic carbon variability under montane ecosystems: assessing the influence of landscape attributes." Thesis, The University of Sydney, 2015. http://hdl.handle.net/2123/14811.

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Soil organic carbon (SOC) is integral to soil functioning and serves as a common indicator for soil security, water security, food security, energy security, climate change abatement, biodiversity protection, and ecosystem service. Since SOC varies in space and time, its quantification is essential to better understand the carbon (C) dynamics at various scales. As a gamut of montane ecosystems, the Himalayan region serves as one of the major C storage pools in the world due to its rich biodiversity and good forest cover. However, much of the Himalayan region is environmentally vulnerable because of rapid socio-economic development taking place, unsustainable land management, and land degradation. As a result, C emissions are steadily increasing in the region and, thus, contributing to global climate change. Despite this, there are still substantial gaps in terms of data and knowledge on SOC in the Himalayas, as in many other part of the globe. Therefore, this thesis was aimed to: (i) investigate the spatial distribution of SOC stock and its variation under different land use and land cover (LULC) types; (ii) examine the vertical distribution of SOC density in relations to LULC types, altitudinal zones, and aspect directions; (iii) determine the complex interrelationships of SOC fractions with LULC types and landform attributes; and (iv) assess the impacts of LULC type on aggregate stability, and hence aggregate size distribution and aggregate-associated organic carbon (AAOC). This study focused on a sub-catchment of Bhutan in the eastern Himalayas. First the SOC stock and its spatial distribution under different LULC types was determined using digital soil mapping technique of regression kriging (RK). Among the several environmental covariates used in RK are altitude, LULC type, slope gradient, and aspect directions. The results show that the mean top one meter SOC stock (mapped to 90 × 90 m grid resolution) decreased in the order of fir > mixed conifer > shrubland > grassland > broadleaf > blue pine > dry land (rain-fed agriculture) > orchard > paddy land. The overall SOC stock for the study area was estimated at 27.1 Mt (average 24.9 kg m-2), which is very high given the relatively small spatial extent of the study area. This indicates that the Himalayan region is characterized by high SOC storage capacity, which needs to be protected to remain as one of the major C sinks in the world. Second, in order to gauge the profile homogeneity of SOC density, its vertical profiles were each fitted with a smooth spline function followed by the estimation of the proportions of SOC density in top 0.20 m relative to the total density in the top one meter. The SOC density homogeneity values under different LULC types, altitudinal zones, and aspect directions were then compared. It revealed that the homogeneity under agricultural land was estimated at 34% compared to 38% for forest, 43% for shrubland, and 59% under grassland. In the case of influence of altitudinal zones on the SOC density, the latter was more uniformly distributed in the 3500-4000 m zone with homogeneity of about 35%, significantly less than 41% estimated for each of the 1769-2500 m and 2500-3000 m zones, and even lesser than 43% for the 3000-3500 m zone. Conversely, the homogeneity of SOC density estimated for different aspect directions indicated that the northern aspect exhibited higher vertical homogeneity compared to other aspect directions whose homogeneity values were indeterminate. These results suggest that vegetation and soil moisture, as influenced by LULC type, altitude, and aspect direction, are the main factors controlling the vertical distribution of SOC density. These outcomes have contributed significantly to our understanding of the conditions favorable to most vigorous vegetative growth and litter production leading to deeper incorporation of organic matter into the soil. The third component of this study was focused on explaining the complex interrelationships of SOC pools with environmental controlling factors of climate, landscape, and anthropogenic. It was hypothesized that the various SOC fractions/pools would respond differently to the environmental factors controlling the physical, chemical, and biological processes. Therefore, the multivariate statistical techniques of canonical correspondence analysis (CCA) was applied to reveal the subtle interrelationships of both the particulate organic carbon (POC) and humic organic carbon (HOC) with the different LULC types and landform attributes as the environmental covariates. It revealed that POC exhibited higher variation than HOC under different LULC types and landform attributes probably due to faster turnover rates of POC compared with that of HOC. Unlike HOC, the POC was largely concentrated in the upper depths of the soil profiles and hence more susceptible to soil erosion and rapid mineralization. The POC and HOC ratio became larger with depth suggesting that SOC becomes more stable with depth. This study also revealed that the influence of the natural LULC types on POC and HOC was higher than was the impacts due to agriculture. The findings have contributed to better understanding of POC and HOC in relation to various environmental factors in maintaining an optimum level of POC and HOC for enhancing sustainable agriculture, environmental quality, and ecosystem services. Lastly, the thesis explored how the vulnerability of the Himalayan region to land degradation can potentially be addressed by studying the impacts of LULC types on aggregate size distribution and stability as influenced by aggregate-associated organic carbon (AAOC). This is aimed to inform appropriate future soil and water conservation measures to combat land degradation. The results of aggregate size distribution show that the large macroaggregates (> 2 mm) accounted for 86-93% of the total aggregates under all LULC types except under dry land (64%) and paddy land (35%). The aggregate stability under different LULC types decreased in the order of fir > shrubland > grassland > orchard > blue pine > broadleaf > mixed conifer > dry land > paddy land. As expected, the AAOC in all aggregate fractions was much higher in the non-agricultural soils than under different agricultural lands. The AAOC in the large macroaggregates constituted more than 76% of the total AAOC across all LULC types except under dry land (65%) and paddy land (38%). Furthermore, the AAOC of the large macroaggregates depicted a similar trend with aggregate stability under different LULC types indicating its significant role in aggregate stability compared to AAOC of other aggregate fractions. The quadratic correlation between aggregate stability and AAOC of the large macroaggregates suggests an upper threshold for SOC to further improve soil aggregation and aggregate stability. In conclusion, this thesis has revealed the spatial/vertical distribution of SOC stocks as impacted by the different controlling factors. The thesis examined the complex interrelations of SOC fractions with LULC and landform attributes to help maintain an optimum level of all functional SOC fractions to improve soil quality. Furthermore, it investigated the microscopic/macroscopic aspects of soil aggregate stability in relation to the AAOC and how this can impact on potential soil degradation in the study region. This is the first systematic study on SOC undertaken in Bhutan which is envisaged to provide the springboard for further investigations across the Himalaya region. The findings of this research are anticipated to contribute in formulating appropriate sustainable land management and C sequestration strategies (e.g. conservation agriculture, agro-forestry, change in land use policy to safeguard and conserve the current forest cover) to combat C emission, soil erosion, and other forms of land degradation, specifically in Bhutan and generally in the Himalayan region. In addition, it is expected to contribute towards land use policy reform agenda to conserve the natural vegetation to ensure continued ecosystem service delivery in the region.

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Buske, Taise Cristine. "COMPORTAMENTO DA UMIDADE DO SOLO DETRMINADA POR MÉTODOS EXPEDITOS." Universidade Federal de Santa Maria, 2013. http://repositorio.ufsm.br/handle/1/7564.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
The knowledge of soil moisture is quite important because it indicates soil hydric conditions and it can help on saving water and electric energy, given that monitoring of soil moisture allows controlled and timely applications of water pointing out how much and when to irrigate, according to the crop water requirements. Therefore, soil moisture should be determined before the irrigation and will serve as a parameter for the amount of water to be applied by the system. There are any methods used for determination of soil water content, in this way, the present study aimed to compare the results of soil moisture obtained by different methods for expeditious determination of the water content of the soil in different textural classes. The study was conducted in the Laboratório de Hidráulica Agrícola da Universidade Federal de Santa Maria . Four methods were tested (standard method, M0; electric oven method, M1, microwave oven method, M2; weighing method, M3) with three soil samples (S1, S2, S3) and three repetitions for each. The linear regression was made between the standard method and alternative methods, for obtaining the correlation coefficient (r), the linear coefficient and the slope, the Wilmott concordance index (Iw) and Performance Index (Id). From the results obtained can be stated that the electric oven method and the microwave oven method have excellent performance when compared to the standard method. The method of weighing presented a performance good and very good. In addition, it was concluded that the 20 minutes period for the electric oven method was efficient signifying a time reduction for the moisture content determination. For the microwave oven method the 5 minute drying period was sufficient and did not differ statistically from the standard method. The method of weighing was also reliable in determining soil moisture. Therefore, it is possible to use alternative methods to determine the soil moisture.
O conhecimento da umidade do solo é de fundamental importância, pois indica em que condições hídricas encontra-se o mesmo, podendo auxiliar na redução dos gastos com água e energia elétrica, haja vista que o monitoramento da umidade do solo possibilita aplicações controladas e pontuais de água, respondendo o quanto e quando irrigar em função das necessidades hídricas das culturas. Assim sendo, para a realização da irrigação, a umidade do solo deve ser determinada anteriormente e servirá de parâmetro para a quantidade de água a ser aplicada pelo sistema. Inúmeros são os métodos utilizados para a determinação do conteúdo de água no solo, dessa maneira, o presente trabalho objetivou comparar os resultados de umidade do solo obtidos pelos diferentes métodos expeditos para determinação do conteúdo de água no solo em diferentes classes texturais. O estudo foi desenvolvido no Laboratório de Hidráulica Agrícola da Universidade Federal de Santa Maria. Foram testados quatro métodos (método padrão de estufa, M0; método do forno elétrico, M1, método do forno de micro-ondas, M2; método das pesagens, M3), com três amostras de solo (S1, S2, S3) e três repetições para cada. Foi feita a regressão linear entre os métodos alternativos e o método padrão de estufa, com a finalidade de se obter o coeficiente de correlação (r), o coeficiente linear e o coeficiente angular, o índice de concordância de Wilmott (Iw) e o índice de desempenho (Id). Através dos resultados obtidos pode-se afirmar que o método do forno elétrico e o método do forno de micro-ondas apresentaram desempenho ótimo quando comparados ao método padrão. O método das pesagens apresentou desempenho bom e muito bom. Também concluiu-se que o tempo de 20 minutos para o método do forno elétrico foi eficiente, significando redução no tempo para determinação da umidade. Para o método do forno de micro-ondas o tempo de 5 minutos de secagem foi suficiente, não diferindo estatisticamente do método padrão. O método das pesagens também se mostrou confiável na determinação da umidade do solo. Portanto, existe a possibilidade de usar os métodos alternativos para a determinação da umidade do solo.

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Sousa, Daniel Vieira de. "Alterações eletroquímicas e sua relação com a produção de gás metano em solos alagados por barragens." Universidade Federal de Viçosa, 2011. http://locus.ufv.br/handle/123456789/5542.

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Fundação de Amparo a Pesquisa do Estado de Minas Gerais
The emission of gases of the greenhouse effect has increased dramatically since the geological era until the present days. Currently the use of fossil fuels and the changing of the use of the Earth are most responsible for the emission of these gases to the atmosphere.The carbon in the soil represents more than three times the carbon in the terrestrial biomass and about two times the carbon in the atmosphere, been a potential source of CO2 and CH4.The biogeochemical process that occurs in the soil or sediments for the emission of gases such as carbon dioxide and methane are controlled by process like the reduction of mineral compounds mainly oxides and amorphous and poor crystalline in anaerobic environment. These process leads to the formation of a favorable habitat suitable to the population grows of Methanogenic bacteria consequently with the production of gases of greenhouse effective. Nowadays there are several projects that defend that the hydroelectric dam offers a great contribution to the emission of the effective of greenhouse gases. This project has the purpose of study what the characteristics has more influence for the production of the emission of greenhouse effective in flood soils in hydroelectric lakes. The chapter one is dedicated to literature review where are addressed the more relevant topics. The chapter II had the purpose of studying the electrochemical dynamics of the soil at Zona da Mata mineira subject to flood due to the construction of hydroelectric. As a result we obtained that how bigger is the of Fe, bigger will be reduction of the soil, which lead us to establish the habitats proper for the establishment of the growth of Methanogenic bacteria‟s. population. The contents of Fe, CO and N have more influence in the ox reduction of flood soil. The chapter III had the purpose of studying dynamics and reactivity of the soil organic carbon (SOC) such as it is also dedicated to estimate the production of CH4 in soils flooded by hydroelectric dams lake with the purpose of identifying which characteristics has more influence in the production of methane comes from an eventually flooded of soils. As a result were obtained that the reactivity of SOC receives influence of the texture of the soil, and the finer is the texture greater is the presence of free fractions. The N shows an important factor to be analyzed due to its relation with the degradation of organic compound and microbial activity.
As emissões de gases do efeito estufa (GEE) têm aumentado vertiginosamente desde eras geológicos até os dias atuais. Atualmente a utilização de combustíveis fósseis, e alterações no uso da Terra, são as maiores responsáveis pelas grandes emissões destes gases para a atmosfera. O carbono contido no solo representa mais de três vezes o carbono contido em toda a biomassa terrestre e cerca de duas vezes o carbono contido na atmosfera, sendo, dessa forma, uma potencial fonte emissora de CO2 e CH4. Os processos biogeoquímicos que ocorrem em solos e ou sedimentos para emissão de gases como o dióxido de carbono e metano, são controlados por processos como a redução de compostos minerais, principalmente óxidos, amorfos e mal cristalizados em ambientes anaeróbios. Estes processos levam a formação de um habitat propício para o crescimento populacional de bactérias metanogênicas, com a conseqüente produção de gases do efeito estufa. Atualmente há diversos trabalhos que defendem que barragem de usinas hidroelétricas oferece uma grande contribuição na emissão de gases do efeito estufa. Nesta pesquisa objetivou-se estudar quais as características do exercem mais influencia para a produção de gases do efeito estufa em solos alagados em lagos de hidroelétricas. O capítulo I é dedicado a revisão de literatura, onde são abordados temas que se julgam relevantes. No capítulo II se objetivou estudar a dinâmica eletroquímica de solos da zona da mata mineira passíveis de serem submetidos a alagamento devido a construção de hidroelétricas. Como resultado obteve-se que quanto maior for a atividade de Fe, maior será o potencial de redução do solo, o que leva ao estabelecimento de habitats, apropriados para o estabelecimento de populações de bactérias metanogênicas. Os teores de Fe, CO e N, são os que mais exercem influencia no processo de oxiredução de solos alagados. O capítulo III teve por objetivo estudar dinâmica e reatividade do carbono orgânico do solo (COS), bem como dedicado a estimar a produção de CH4 em solos alagados por lagos de usinas hidroelétricas, com o intuito de identificar quais características exerce mais influência na produção de metano, provinda do eventual alagamento dos solos. Como resultados foram obtidos que a reatividade do COS recebe influencia da textura do solo, sendo que quanto mais fina a textura maior a presença de frações livres. O N total se mostra um importante fator a ser analisado devido sua relação com a degradação de compostos orgânicos e atividade microbiana.

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Michali, Aphrodite-Ioanna. "Méthode pour l'identification des paramètres d'une loi élastoplastique à partir d'essais de laboratoire et in-situ : Modélisation numérique du tassement d'un remblai sur sol compressible." Châtenay-Malabry, Ecole centrale de Paris, 1994. http://www.theses.fr/1994ECAP0384.

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Les paramètres d'une loi élastoplastique incrémentale ont été identifiés a partir d'essais de sols raisonnablement envisageables, comme des essais triaxiaux drainés et non-drainés en petites et grandes déformations et des essais dométriques. La combinaison avec des essais effectués in-situ, comme le sont les essais pressiométriques, ont complété et mis en évidence les paramètres les plus influents pour chaque type de calcul. La procédure suivie pour l'identification des paramètres contient deux branches importantes: 1) simulation d'essais de laboratoire triaxiaux NC drainés et non-drainés qui nous ont donné l'angle de frottement Ø et la pression critique de référence Pc0, comme aussi les paramètres numériques de la loi comme , a et b. Des essais dométriques ont donné la valeur de la compressibilité plastique b et les paramètres numériques c, ccyc, riso à partir de la décharge. Nous avons constaté une impuissance de la loi à restituer convenablement ce chemin car nous n'arrivons pas à atteindre la valeur du déviateur donnée par l'expérience. Ainsi nous avons proposé une modification de la fonction de la surface de charge qui donnera des simulations des essais triaxiaux non-drainés très satisfaisantes. 2) simulation du chemin pressiométrique drainé et couplé. Cette modélisation a posé des problèmes d'ordre numérique d'abord que nous avons essayé de résoudre en choisissant le maillage et son raffinement capable de résoudre tous les cas de calculs. En essayant de traiter les problèmes reliés à la modélisation des problèmes couplés, nous avons présenté le comportement des différents types d'éléments pour des conditions différentes de perméabilité et de compressibilité du fluide. Ce sont les paramètres de l'état critique qui jouent le rôle principal dans cette simulation. Pour les essais draines nous avons la pression critique de référence Pc0, l'angle de frottement Ø et la compressibilité plastique β, pour l'essai couplé se sont seulement Pc0 et l'angle de frottement Ø. Le module élastique E joue un rôle important pour les essais couplés et il peut être identifié par l'essai pressiométrique dans le cas ou nous ne disposons pas d'essais en petites déformations. Le calcul de la consolidation d'un remblai sur sols mous a montré l'importance des paramètres comme la distance d'entre les droites isotropes et de l'état critique, la perméabilité in-situ, et bien sur la bonne connaissance de l'etat initial des contraintes et de l'indice des vides. Les paramètres utilisés pour effectuer ce calcul aux limites avec l'aide d'un code d'éléments finis (Gefdyn) ont été identifiés avec la méthode proposée dans le but d'effectuer des calculs d'ouvrages de génie civil prévisionnels d'une manière fiable.

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Andrieux, Luc. "Pour une philosophie du tact relationnel dans le soin." Thesis, Lyon 1, 2013. http://www.theses.fr/2013LYO10260.

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Dans le cadre de la relation de soin, l'action soignante du prendre soin est souvent associée à la recherche de ce qui serait la juste distance professionnelle. Les problématiques habituelles de l'identification d'une limite objective opérant une séparation entre deux intériorités afin de garantir l'espace d'une intimité, relèvent d'une conception réductrice fondée sur une représentation où intériorité et extériorité s'excluent mutuellement. Le concept de tact relationnel, permet de sortir de cette impasse par le fait qu'il pose le problème sous l'angle d'un espace corporel qui se constitue dans une relation duale sans cesse réinventée dans un art du faire. Cette habileté tactilaire combinant un art pratique qui mobilise des savoirs et des manières d'être spécifiques, se fonde sur un sens esthétique (tactilairité) qui sait subtilement toucher les espaces de l'intériorité mouvante du soi. Elle parvient à appréhender l'aire de l'intime grâce à un art de l'appréciation de l'intouchable, par une plasticité des espaces symboliques du corps et par une activité de la pensée qui ne sauraient être dissociées. Ainsi le tact relationnel est moins en lien avec le toucher comme le suggère sa parenté étymologique et métaphorique avec le tact sensoriel, qu'avec la recherche habile et délicate d'une reconnaissance mutuelle au fondement des interactions intersubjectives dont le corps et sa gestuelle constituent le support le plus explicite. Le tact comporte ainsi des principes informels spécifiques qui ne peuvent se confondre avec les seules règles de la politesse
The concept of tact is usually associated with the idea of touching, which is the genuine etymology. However, relational tact concerns a very special aspect of touching, because it is a none physically touching act regarding a kind of attitude trying to preserve anyone from the humiliation of being taken as an object rather than as a subject. Healthcare relationships especially have to be examined thoroughly by the way of tact in order to understand the fundamental human need for respect hidden in tact. Different from politeness, tact is the specific art of respecting others without conventional and formalized rules. It needs a capacity of building an area in which the partnerships can find a mutual respect of each other. According to interactionism sociology tact is really a face work that needs an ability never really taught in medical studies. Thanks to interactionism we can emphasize the base of these relationship attitudes. They depend on the frame in which interactions take place. This area must be though together with other concepts because of the weakness of the former ones. So, tactilairity could translate the capacity of making an informal area in every meeting and especially in healthcare relationships. Tactilairian ability is one of the ways to efficiently succeed in pacified relationships

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Roux, Julien. "Conception d'un capteur distribué pour la surveillance de l'état hydrique des sols." Thesis, Toulouse, INSA, 2017. http://www.theses.fr/2017ISAT0031/document.

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A cause du développement du smart farming, des études sont à mener sur la distribution de l’instrumentation pour mesurer l’état hydrique du sol en vue de contrôler l’irrigation. Dans le cadre du projet IRRIS, nous réalisons un capteur d’humidité du sol intelligent. Nous allons tout d’abord réaliser le corps d’épreuve de ce capteur. Nous choisissons une mesure capacitive pour obtenir un capteur réactif malgré un coût de réalisation faible. Le corps est cylindrique pour pouvoir être inséré facilement dans le sol. Les électrodes sont réalisées par dépôt électrochimique de cuivre sur ce cylindre plastique. Nous concevons ensuite l’électronique de mesure associée à ce corps. Pour cela, nous comparons deux solutions, l’une analogique et l’autre logicielle. Puis nous assemblons notre capteur suivant deux modes, le multi capteur ou le mono capteur. Nous réalisons à cette étape la création du réseau de capteurs à l’aide de communication sans fil située dans la bande ISM 868MHz et nous la caractérisons. Enfin, nous observons les résultats de trois campagnes de mesures dans des champs cultivés pour valider le fonctionnement sur différents types de sols et de cultures. Ces travaux aboutissent donc à la création d’un capteur permettant la mesure de l’humidité du sol avec un coût réduit par rapport aux capteurs industriel déjà existant. Les expérimentations sur site montrent sa facilité d’insertion ainsi que son bon fonctionnement
Owing to the development of the smart farming, some new studies need to be lead on a distributed instrumentation to measure soil moisture to control the irrigation.In the project IRRIS context, we realize a smart soil moisture sensor. First, we have to realize the sensing element of this sensor. We choose a capacitive detection to get a reactive sensor despite low cost. The body is a cylinder to be easily buried in the soil. The electrodes are made by electrochemical deposition on the plastic tube. Then, we design the measurement electronic. We compare two solutions, one with discrete components and the other software on embedded microcontroller. We submit those electronics at thermic variations to observe their comportment to create the law of compensation. Next we assemble the sensor according to two ways. The first, the multi sensor, forces the depths of sensing but reduces the costs by pooling the measurement electronic. The second, the mono sensor, frees the choice of depth but multiplies the number of sensors. We create at this step the sensor network thanks a wireless communication placed on 868MHz, an ISM band that we characterize in terms of range depending on the flow rate to optimize this communication. Finally, we observe the results of three measurement campaigns to validate the operating for different soil and cultures.This study ends in the realization of a sensor to measure soil moisture with a reduced cost relative to the industrial sensor on the market. Experiments prove its ease of use as well as its proper functioning

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CIRCELLI, Luana. "Integration Vis-NIR spectroscopy and satellite Sentinel-2 data to assess soil organic carbon pool of an organic farm in south of Italy." Doctoral thesis, Università degli studi del Molise, 2021. http://hdl.handle.net/11695/106279.

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Il suolo svolge un ruolo importante nel ciclo globale del carbonio e l’equilibrio tra i tassi di input e output determina su larga scala la quantità e il turnover del carbonio organico del suolo (SOC). Pertanto, il suolo può fungere sia da deposito di carbonio che da fornitore di emissioni dello stesso aumentando i gas serra atmosferici (GHGs), con un grande potenziale nella mitigazione dei cambiamenti climatici. I cambiamenti nell’uso del suolo sono quelli particolarmente coinvolti nell’accumulo di SOC e nella perdita di anidride carbonica (CO2) nell’atmosfera sotto forma di GHGs. A tal fine, è necessario applicare una gestione sostenibile del territorio per aumentare lo stoccaggio e il sequestro del carbonio. Tuttavia, è importante effettuare apriori una valutazione della composizione del SOC, per comprendere i meccanismi attraverso i quali i pool di carbonio del suolo possono essere direttamente collegati al suo potenziale di sequestro della CO2 atmosferica. Lo studio del carbonio organico del suolo spazia da contesti di piccola a larga scala, e l’applicazione delle tecnica spettroscopica Vis-NIR può unire gli aspetti positivi di analisi del suolo ad alta risoluzione all’analisi dello stesso a larga scala mediante facile applicabilità. In questo contesto, come tecnica rapida per misurare il carbonio organico basata sulla riflettanza diffusa del suolo, è stata applicata la spettroscopia Vis-NIR successivamente integrata con i dati satellitari di Sentinel-2. Con l’obiettivo di analizzare i pool di carbonio organico e inorganico, sono stati scelti i terreni di un’azienda agricola biologica nel sud Italia. In questa azienda agricola vengono adottati i principi dell’agricoltura conservativa per la coltivazione delle mele. I pool di carbonio organico e inorganico sono stati misurati applicando diversi metodi chimici, dalla combustione a secco ad alta temperatura, mediante analizzatore CNS per la misurazione del carbonio totale e organico, a procedure di ossidazione a umido, anche per forme solubili di carbonio. Questa differenziazione nei metodi ha permesso di fare una prima distinzione tra le forme organiche di carbonio più stabili (recalcitranti) nel suolo da quelle più labili e maggiormente soggette a fenomeni di mineralizzazione. I modelli di regressione spaziale hanno permesso di conoscere l’influenza dei parametri topografici e di altre proprietà del suolo sulla dinamica dei pool di carbonio organico e inorganico. La spettroscopia Vis-NIR, come tecnica di rilevamento prossimale, è stata utilizzata per modellare le calibrazioni e le validazioni per la previsione delle frazioni di carbonio del suolo indagate. Dalle combinazioni tra i diversi modelli di pre-elaborazione spettrale e di regressione, le trasformazioni in derivata seconda e le regressioni partial least square (PLS) hanno ottenuto buoni risultati, valutati mediante gli indici di R2=0.85 e RPD=2.5 per le previsioni del carbonio organico del suolo, e R2=0.75 e RPD=1.7 per quello inorganico. Le valutazioni e le predizioni dei pool di carbonio del suolo dalla scala di campo a quella aziendale sono state ottenute integrando i dati satellitari di Sentinel-2 nei modelli predittivi Vis-NIR. I risultati accurati ottenuti hanno dimostrato che il telerilevamento può essere un potente strumento per riconoscere i vari pool di carbonio del suolo, soprattutto quelli più esposti al rischio di degrado ed erosione. Per di più, la combinazione tra analisi tradizionale da laboratorio dei suoli e la spettroscopia Vis-NIR estesa con i dati satellitari può essere molto utile in approcci di agricoltura di precisione.
The soil plays an important role in the global carbon cycle and the balance between the rates of organic carbon input and output determines at large scale the amount and the turnover of soil organic carbon (SOC). Thus, soil can act as both carbon store and supplier of carbon emissions increasing atmospheric greenhouse gases (GHGs), having a great potential in climate change mitigation. Changes in land use are those particularly involved in SOC accumulation and in loss of carbon dioxide (CO2) in the atmosphere as GHG. With this purpose, sustainable land management are necessary to be applied for carbon storage and sequestration. However, assessing the composition of SOC is important to understand the mechanisms through which soil C pools can be directly linked with its potential to sequester atmospheric CO2. The study of the SOC composition span from the micro to the macro-scale, and the application of Vis-NIR spectroscopy technique can couple some positive aspects of the resolution of the fine scale with a wide and easy applicability. In this framework, as a rapid technique for measuring SOC based on the diffuse soil reflectance, the application of Vis-NIR spectroscopy and integration with satellite Sentinel-2 data were applied. With the aim to analyze the organic and inorganic C pools, the soils of an organic farm in South of Italy were chosen. In this farm, the principles of conservation agriculture are adopted in apple cultivation. The organic and inorganic C pools were measured on 56 georeferenced soil samples, for a total study area of about 3 hectares, applying different methods, from dry combustion at high temperature, CNS analyzer and furnace loss on ignition for total and organic C, to wet oxidation procedures, also for soluble forms of organic C. This differentiation in methods allowed making a distinction between the more stable (recalcitrant) organic C forms in the soil from the more labile ones and more subject to mineralization phenomena. Spatial regression models allowed taking into account the role of topographical parameters and other soil properties on dynamics of organic and inorganic C pools. Vis-NIR spectroscopy, as a proximal sensing technique, was used to model calibrations and validations for the prediction of the investigated soil C fractions. From the combinations between different spectral preprocessing and regression models, second derivative transformations and partial least squares (PLS) regression have achieved excellent results, made by the average values of R2=0.85 and RPD=2.5 for soil organic C predictions, and R2=0.75 and RPD=1.7 for soil inorganic C. The evaluation gap of soil C pools from field to farm scale was improved by the satellite Sentinel-2 data in Vis-NIR predictive models. The obtained accurate results proved that remote sensing could be a powerful tool to recognizing the various soil C pools, especially those most exposed to the risk of degradation and erosion. In addition, the combination between soil laboratory analysis and Vis-NIR spectroscopy and satellite data can be very useful with a precision agriculture approach.

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Lima, Patricia Tavares de. "Cordierita : sintese por processamento sol-gel." [s.n.], 1998. http://repositorio.unicamp.br/jspui/handle/REPOSIP/249760.

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Orientador: Celso Aparecido Bertran
Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica
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Mestrado

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Perusi, Maria Cristina [UNESP]. "Discriminação de argissolos e avaliação da estabilidade de agregados por vias seca e úmida em diferentes sistemas de uso e manejo." Universidade Estadual Paulista (UNESP), 2005. http://hdl.handle.net/11449/101956.

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In order to discriminate ARGISSOLOS and to evaluate aggregates stability by dry and humid ways under different use and management systems, it was studied soil profiles under agricultural and pasture for more than twelve five years on the following system: six years with annual crop rotation in areas that had been pasture for the same time period and forest, for comparison purposes. This study was done in a agricultural farm in the Anhumas county, São Paulo state, Brazil, where the predominant soil class - ARGISSOLO - are representative of the region. Stages to achieve the objectives: a) not deformed and deformed samples collection to perform chemical and physical analysis; b) determination of the aggregate percentage by dry and humid ways; c) computation of the weighted mean diameter of the aggregates (WMDA); d) soils classification; e) statistical analysis: variance analysis and Tuckey's test for average, at 5 % of probability. Main conclusions: soil classification; the organic matter content of the A horizon of the soil under forest is 64 % more than the soil under pasture e 79 % more than the soil under annual crop; the flocculation degree and amount of the clay fraction of this same horizon is 31 % more than the soil under pasture e 39 % more than the soil under annual crop; the weighted mean diameter of the aggregates obtained by dry (D) and (H) humid ways of the A horizon and its mean value for the soils decrease in the following sequence: PVAd - forest > PVe - pasture > PVd - annual culture, respectively, with the following values: 1.33560 and 1.445496 (D), 2.81114 and 2.351380 (H); 0.66748 and 1.011830 (D), 2.79642 and 1.624250 (H); 0.32468 and 0.993775 (D), 1.25808 and 0.983135 mm (H); the weighted mean diameters of the aggregates of the A horizon - obtained by dry (D) and humid (H) ways - decreased 50 % and 1 % in the soil under pasture... (Complete abstract click electronic access below)

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Miqueloni, Daniela Popim [UNESP]. "Perda de solo em área de nascentes caracterizada por análise multivariada e modelos de geoestatística." Universidade Estadual Paulista (UNESP), 2011. http://hdl.handle.net/11449/88295.

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Devido sua importância, a perda de solo das microbacias de cabeceira do Córrego do Tijuco-SP foi estimada por meio da EUPS, e a variabilidade espacial dos fatores do processo erosivo foi investigada pelas análises multivariada e geoestatística. A perda de solo média estimada foi considerada alta, 118,50 Mg ha-1 ano-1, e a correlação de Pearson confirmou o fator erodibilidade do solo como o fator mais importante no processo erosivo. A erodibilidade local é condicionada pela distribuição das frações granulométricas e matéria orgânica, sendo o solo basicamente de textura média/arenosa de baixa coesão. Próxima a zona urbana, a interação do fator erosividade da chuva e do fator práticas conservacionistas se mostrou proeminente evidenciando alta perda de solo devido à concentração de água oriunda da camada impermeabilizada urbana e da falta de controle da velocidade do escoamento superficial da água. Em contraste, o fator cobertura vegetal mostrou maior atuação nas áreas de vegetação permanente, localizadas principalmente nas nascentes e canais de escoamento. Nas áreas mais convexas do terreno, localizadas nos divisores de águas, a atuação do fator erodibilidade foi proeminente, em contraste com o fator topográfico, este em áreas côncavas de maior declividade. Foram observadas ainda áreas com atuação conjunta dos fatores topográfico e erodibilidade, refletindo locais de inclinação mais suave, porém com alto potencial natural de erosão. Os resultados das análises multivariadas e geoestatística permitiram uma estratificação da área estudada identificando locais com propriedades específicas quanto à perda de solo o que contribui na compreensão do processo erosivo para a aplicação das práticas conservacionistas
Because of the importance of headwater watersheds of the Córrego do Tijuco-SP its soil loss was estimated by the USLE and the spatial variability of the erosion process factors was investigated by multivariate analysis and geostatistics. The estimated average soil loss was considered high, 118.50 Mg ha-1ano-1, and Pearson correlation confirmed the soil erodibility factor as the most important factor in the erosion process. Erodibility is conditioned by the local distribution of soil particle-size fractions and organic matter, and soil texture mostly medium/sandy of low cohesion. Near urban areas, the interaction of rainfall erosivity factor and conservation practices factor showed prominent high soil loss due to concentration of water coming from urban soil impermeabilization and the lack of speed control of runoff water. In contrast, the vegetation cover factor showed great performance in the areas of permanent vegetation, mainly located in the headwaters and drainage channels. In areas of more convex topography close to the watershed dividers, the action of erodibility factor was prominent, in contrast to concave areas of greater slope where the topographic factor was more prominent. We also observed areas with joint action of topographic factors and soil erodibility factor, with smoother topography, but with high natural potential of erosion. Results of multivariate and geostatistics analysis enabled to stratify the study area by identifying sites with specific properties of soil loss which helps in understanding the erosion process for the implementation of conservation practices

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48

Augusto, Carlos Henrique. "Zonas homogêneas de manejo por meio de variáveis edafoclimáticas e de produtividade." Universidade Estadual Paulista (UNESP), 2018. http://hdl.handle.net/11449/153199.

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O aumento da população mundial e a limitada área disponível para a produção de alimentos, exige que busquemos cada vez mais técnicas e tecnologias que aumentem a produtividade das áreas agrícolas. A produtividade de uma determinada cultura depende de diversos fatores, e conhecer os fatores que mais influenciam a determinação do seu potencial produtivo pode contribuir para a tomada de decisão em relação à utilização e gestão de recursos. Utilizando dados de monitores de colheita da cultura da soja nas safras de 08/09, 10/11, 11/12, 12/13, 14/15 e 15/16, dados de precipitação destes anos, mapa de Condutividade Elétrica (CE) e das características químicas do solo para as safras de 09/10, 13/14, 14/15 e 15/16, este trabalho teve o objetivo de identificar os fatores mais relevantes para a determinação da produtividade da soja para auxiliar na determinação de Zonas Homogêneas de Manejo (ZHM) baseadas nestas características críticas. Comprovou-se que a disponibilidade de água é a principal determinante da produtividade da soja nas condições estudadas, sendo que a precipitação no mês de setembro, mês de implantação da cultura, apresentou-se como o fator mais crítico. Utilizando o mapa de produtividade média da cultura durante os anos estudados e o mapa de CE, foi possível identificar as áreas de potencial produtivo, mas a definição de ZHM mostrou-se desafiadora pois as características químicas do solo apresentaram alta variabilidade temporal, dificultando a determinação do manejo que poderia melhor explorar as áreas de maior ou menor potencial produtivo.
The growing world population and the limited area available for food production requires us to progressively seek techniques and technologies that increase the yield of agricultural crops. The yield of a crop depends on several factors and knowing the factors that most influences its yield potential can contribute to the decision making process regarding the use and management of resources. Using data from soybean yield monitors of 08/09, 10/11, 11/12, 12/13, 14/15 and 15/16 season, precipitation data from these years, Electric Conductivity (EC) map and the chemical characteristics of the soil for the 9/10, 13/14, 14/15 and 15/16 crops, this work had the objective of identifying the most relevant factors that determine soybean yield to assist in the determination of Homogeneous Management Zones (HMZ) based on these critical characteristics. The availability of water was the main factor of soybean yield under the conditions the study was carried out, and the precipitation in September was the most critical factor, being the month in which the crop was seeded. Using the average productivity map and the EC map, it was possible to identify areas of yield potential, but the definition of HMZ was challenging because the chemical characteristics of the soil had high temporal variability, making it difficult to determine the best management to explore the areas of greater or lesser yield potential.

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49

Fedrigo, Jean Kássio. "Recuperação de pastagens naturais degradadas por sobrepastejo, por meio do diferimento." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2015. http://hdl.handle.net/10183/128120.

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A herbivoria em pastagens naturais apresenta papel de destaque no direcionamento das dinâmicas vegetacionais, determinando modificações na estrutura da vegetação, nos padrões de biodiversidade e na produtividade do sistema. Essas alterações, que de modo geral contribuem para a sustentabilidade dos ecossistemas em níveis moderados de intensidade de pastejo, podem dar origem a processos de degradação ambiental quando a lotação animal utilizada é superior à capacidade de suporte das pastagens. O objetivo do presente trabalho foi avaliar a capacidade de recuperação dos padrões de diversidade, composição botânica, biomassa de forragem, altura do pasto, interceptação luminosa e do banco de sementes de uma pastagem natural degradada por sobrepastejo, por meio do diferimento, tomando como base uma área de referência. Três tratamentos baseados em exclusões estacionais do pastejo (Diferimento de Primavera, Diferimento de Outono e Pastoreio Contínuo) com três repetições foram aplicados simultaneamente em áreas manejadas por um longo período com duas intensidades de pastejo: severa e moderada (utilizada como área de referência). A pastagem manejada com pastejo severo apresentou rápida alteração na composição botânica e nos padrões de diversidade em resposta ao diferimento. Depois de dois anos de exclusões temporárias do pastejo, a composição botânica da vegetação estabelecida e do banco de sementes dessa área sofreu alterações nos grupos funcionais de gramíneas na direção das espécies características da comunidade vegetal sob pastejo moderado. Também foram verificados importantes incrementos na biomassa de forragem, altura e interceptação luminosa. A comunidade vegetal sob pastejo moderado apresentou maior equilíbrio entre diferentes grupos funcionais de plantas, especialmente entre espécies com hábitos de crescimento prostrado e cespitoso. Essa condição favoreceu o aparecimento de estrutura espacial na distribuição das espécies de plantas, maior diversidade, riqueza e melhores condições estruturais do pasto. O diferimento realizado na moderada intensidade de pastejo proporcionou dominância de espécies cespitosas, determinando decréscimo na diversidade e riqueza de plantas. As épocas de diferimento apresentaram padrões de resposta semelhantes dentro de cada intensidade de pastejo, com magnitude superior para o diferimento de primavera. Os resultados revelam a importância do diferimento do pastejo como uma ferramenta para a recuperação de pastagens degradadas por sobrepastejo.
The herbivory on natural grasslands has a prominent role in driving vegetation dynamics, determining changes in vegetation structure, biodiversity patterns and primary and secondary productivity. These changes, which generally contribute to the ecosystems sustainability at moderate grazing intensities, can cause environmental degradation when the stocking rate used is higher than the pasture carrying capacity. The objective of this study was to evaluate the efficiency of temporary grazing exclusion to restore diversity, botanical composition, forage biomass, sward height, light interception and soil seed bank from a natural grassland degraded by overgrazing based on a reference area. Three treatments based on seasonal grazing exclusions (spring deferment, autumn deferment and continuous stocking) with three replications were applied simultaneously in areas managed for a long period with two grazing intensities: severe and moderate (used as reference area). The pasture managed under severe grazing showed a rapid change in botanical composition and diversity patterns in response to grazing exclusions. After two years of temporary grazing exclusions, grass functional groups of the established vegetation and soil seed bank from overgrazed pasture changed toward the characteristic species of plant community under moderate grazing. We also verified significant increases in forage biomass, sward height and light interception. The plant community under moderate grazing intensity showed better balance between different functional groups of plants, especially among species with prostrate and cespitose growth habits. This condition favored the spatial structure of appearance in the distribution of plant species, greater diversity, species richness and better structural pasture conditions. The grazing exclusion in moderate intensity grazing provided dominance tussock species, determining decrease in the diversity and richness of plants. The deferment periods showed similar response patterns within each grazing intensity with higher magnitude for spring deferment. These results reveal the importance of grazing exclusion as a tool for the recovery of degraded pastures by overgrazing.

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50

Pocaznoi, Diana. "Optimisation d'anodes microbiennes à partir de lixiviat de sol pour la conception de piles à combustible microbiennes." Thesis, Toulouse, INPT, 2012. http://www.theses.fr/2012INPT0053/document.

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Les piles à combustible microbienne (PACMs) sont des piles capables de convertir l'énergie chimique de combustibles organiques directement en énergie électrique. Dans ces piles, l'oxydation du combustible est assurée par des micro-organismes dits "électro-actifs" qui forment des biofilms à la surface de l'anode et jouent le rôle de catalyseur des réactions électrochimiques. Les travaux qui font l'objet de ce manuscrit ont eu pour objectif d'optimiser des anodes microbiennes formées à partir de la flore bactérienne contenue dans des terreaux de jardin. Les expériences effectuées en chronoampérométrie avec un système à trois électrodes ont conduit à la première démonstration expérimentale que des densités de courant de 66 A/m2 pouvaient être obtenues en formant les anodes microbiennes sur des ultra-microélectrodes. Sur des électrodes de taille normale, la mise au point d'une nouvelle technique (polarisation retardée) pour la formation de biofilms microbiens a permis d'obtenir des densités de courant de 9,4 A/m2 après seulement 3 jours de polarisation tandis que le protocole conventionnel demandait quelques semaines pour obtenir 6 à 8 A/m2. L'étude de différents matériaux d'électrode a indiqué que l'acier inoxydable qui permit d'atteindre des densités de courant de 21 A/m2 présente un grand intérêt pour la formation de biofilms électro-actifs. En effet, les électrodes en tissu de carbone ont assuré jusqu'à 34,3 A/m2, voire 50 A/m2 en anaérobiose, mais elles bénéficiaient d'une structure tridimensionnelle. La mise en oeuvre des anodes microbiennes optimisées dans les PACMs a assuré la production de 6,0 W/m2. L'élaboration d'un nouveau prototype intégrant un système de cathode amovible a permis d'allonger la durée de vie initiale de la pile de 2 semaines à plus de 2 mois
Microbial fuel cells (MFC) are devices capable to convert chemical energy from organic fuels directly into electrical energy. In these cells, the fuel oxidation is provided by micro-organisms known as "electro-active"; these microorganism form biofilms on the surface of the anode and act as a catalyst for electrochemical reactions. The aim of this work was the optimisation of microbial anodes formed from bacterial flora contained in garden soils. The chronoamperometric experiments performed in a three-electrode system showed for the very first time in these systems that current densities of 66 A/m2 could be obtained by forming microbial anodes on ultra-microelectrodes. On electrode of normal size, the development of a new technique (delayed polarisation) for designing microbial biofilms produced current densities of 9.4 A/m2 after 3 days of polarisation, while the conventional protocol asked a few weeks for obtaining 6 to 8 A/m2. The study of different electrode materials indicated that stainless steel allowed reaching current densities up to 21 A/m2, which makes it a suitable candidate for designing electro-active biofilms. Indeed, the carbon electrodes provided up to 34.4 A/m2, even 50 A/m2 in anaerobic conditions, but the electrodes benefited of a three-dimensional structure contrasting the stainless steel electrode. The use of optimised microbial anodes in MFCs insured the production of 6 W/m2. In addition, the development of a new prototype containing a removable cathode allowed extending the lifetime of the initial MFC from 2 weeks to over 2 months

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Dissertations / Theses on the topic 'Poor soil'

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