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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
141

Zvláštní ekonomické zóny v Číně: aktuální trendy a výkonnost vybraných ekonomických zón / Special economic zones in China: current trends and performance of selected economic zones

Papugová, Tereza January 2013 (has links)
Special Economic Zones have been a popular instrument for fostering economic growth. The SEZ's main aim is to attract foreign investors into the country, thus providing necessary capital for economic development. Diploma thesis focuses on application of this approach in China and provides analysis of origin, economic situation and future prospects of these areas. At first, the concept of special economic zone is theoretically defined for the further usage in chinese context. Thesis also offers a comparison with export processing zones and SEZs in India to provide a broader perspective of the concept of special economic zones in the world. Hereafter, the development and performance of SEZs in chinese provinces Guangdong, Fujian and Hainan are presented. Furthermore, the current challenges for the zones to face are identified. Those challenges will be crucial for zones to cope with in order to keep up the pace with today's trend of liberalisation and international cooperation in the worldwide economy.
142

Lomové chování tepelně ovlivněné oblasti heterogenního svarového spoje / Fracture behaviour of heat affected zone near heterogeneous weld joint

Jelínek, Vladimír January 2012 (has links)
The study deals with mechanical characteristic of heterogeneous weld joint. The low carbon steel 22K and austenitic steel have been used as a experimetnal materials. The low carbon steel has special properties in basic condition. The sample has been evaluated in basic condition and after annealation. There have been evaluated impact of annealation proces to structure and mechanical charakteristics in experimental part of study. The particularised analysis of microstructure has been done by pictorial analysis. Mechanical characteristics has been examinated in both conditions by 2 different methods – measurment of microhardness according to Vickers and test of fracture toughness on compact tension specimens.
143

Structure-Property Relationships of an A36 Steel Alloy under Dynamic Loading Conditions

Mayatt, Adam J 15 December 2012 (has links)
Structure-property quantification of an A36 steel alloy was the focus of this study in order to calibrate and validate a plasticity-damage model. The microstructural parameters included grain size, particle size, particle number density, particle nearest neighbor distances, and percent of ferrite and pearlite. The mechanical property data focused on stress-strain behavior under different applied strain rates (0.001/s, 0.1/s, and 1000/s), different temperatures (293 K and 573 K), and different stress states (compression, tension, and torsion). Notch tension tests were also conducted to validate the plasticity-damage model. Also, failure of an A36 I-beam was examined in cyclic loads, and the crack growth rates were quantified in terms of fatigue striation data. Dynamic strain aging was observed in the stress-strain behavior giving rise to an important point that there exists a critical temperature for such behavior.
144

Will green banking unlock a sustainibility transition towards a low-carbon economy? : The perspective of a member-owned bank in Sweden / Kommer gröna banker möjliggöra en hållbarhetsövergång till en koldioxidsnål ekonomi? : En svensk medlemsägd banks perspektiv

Solheim, Ulrika January 2019 (has links)
In the climate change discussion, there is a broad consensus about the importance of support from the financial industry when it comes to supporting changes towards a more sustainable society. However, investments in the society supporting a transition towards a low-carbon economy are still waiting to become unlocked. This thesis aims to provide an understanding of a possible sustainability transition towards a low-carbon economy within the Swedish financial industry. To fully understand a possible change, this study has investigated the dynamics of the financial industry from the perspective of a member-owned bank in Sweden. Hence this study seeks to explore a fundamental and comprehensive change, the theoretical framework of socio-technical transition and the multi-level perspective is used. This contributes to a vast mapping of the financial industry and a better understanding of the dynamics of social change and innovation, such as a low-carbon economy transition. To gain in-depth knowledge, a case study was performed. Both qualitative and quantitative data was collected through semi-structured interviews and data from the case company’s customer database. The carbon footprint of the case company bank’s loan portfolio was calculated and analysed through a sensitivity analysis. This was done in the aim to gain deeper insights about how actions from a bank could contribute to a low-carbon economy. The empirical findings in this thesis showed that a bank does have the ability and power to contribute to a lower carbon footprint in a bureaucratic and stable regime as the financial industry. However, this responsibility could be hard to put at a single actor. As the financial industry has a strong carbon lock-in, the approach has to be long-term. The actions that could enable a sustainability transition within the financial industry seems to be a collection of many different transition pathways. By remaining the landscape pressure and the development of niche innovations, a long-term sustainability transition seems imaginable. By collecting the forces of regulatory work along with collaboration among incumbent actors and increasing development of new low-carbon financial products, there is positive movement. With patience and an attitude change, the financial industry can see a sustainability transition in the horizon. / I diskussionen om klimatförändringar finns det en enighet om vikten av stöd från finansbranschen när det gäller förändringar mot ett mer hållbart samhälle. Investeringar i samhället som stöder en övergång till en koldioxidsnål ekonomi väntar dock fortfarande på att slå igenom. Denna uppsats har som syfte att förstå en möjlig hållbarhetsövergång till en koldioxidsnål ekonomi inom den svenska finansbranschen. För att förstå en möjlig förändring har denna undersökning granskat finansbranschens dynamik utifrån en svensk medlemsägd banks perspektiv. Då denna uppsats strävar efter att utforska en grundläggande och omfattande förändring, så har det teoretiska ramverket för socio-teknisk övergång och multi-nivåperspektivet används. Detta bidrar till en omfattande kartläggning av finansbranschen samt en bättre förståelse för dynamiken i socialförändring och innovation, så som en övergång till en mer koldioxidsnål ekonomi. För att få fördjupad kunskap inom ämnet så har en case-studie utförts. Både kvalitativa och kvantitativa data har samlats in genom halvstrukturerade intervjuer och data från case-företagetskunddatabas. Koldioxidavtrycket i case-företagets utlåningsportfölj beräknades och analyserades genom en känslighetsanalys. Detta gjordes i syfte att få djupare insikter om hur åtgärder från enbank skulle kunna bidra till en koldioxidsnål ekonomi. De empiriska resultaten i denna studie visade att en bank har förmågan och kraften att bidra till ett lägre koldioxidavtryck i en byråkratisk och stabil regim som finansindustrin. Detta ansvar kan dock vara svårt att lägga på en enskild aktör. Eftersom finansbranschen idag har investeringar i koldioxidtunga aktiviteter måste tillvägagångssättet vara långsiktigt. De åtgärder som kan möjliggöra en hållbar övergång inom finansbranschen verkar vara en samling av många olika övergångsbanor. Genom att ha fortsatttryck från landskaps-nivån och en fortsatt utveckling av nisch-innovationer verkar en långsiktig hållbarhetsövergång tänkbar. Genom en enad kraft, samarbete mellan etablerade aktörer och ökad utveckling av nya finansiella produkter med låg koldioxidutsläpp, verkar en förändring möjlig. Med tålamod och en attitydförändring kan finansindustrin se en hållbarhetsövergång i horisonten.
145

Mining for the low-carbon transition : Conflicting discourses of sacrifice zones and win-win narratives

Andersson, Isabella January 2021 (has links)
To support the transition towards a low-carbon economy, mining companies, international financial institutions and governments are preparing to drastically scale up mineral extraction of energy transition minerals such as cobalt and lithium. Mineral extraction, however, has far-reaching impacts on the biophysical environment and mining-affected communities that may become more severe under a changing climate. In May 2019, the World Bank sought to respond to these challenges with the launch of its climate-smart mining Facility, evoking critique from non-governmental organisations working in solidarity with frontline communities. Drawing on poststructuralist political ecology and discourse analysis, this study examines the conflicting narratives on mining for the energy transition and interrogates the political solutions made conceivable through these narratives. Utilizing documents by proponents and opponents of the climate-smart mining Facility, and semi-structured interviews, the analysis reveals two contrasting discourses on mining for the energy transition, problematising climate change as a problem of rising CO2 emissions, and as a social justice problem rooted in global inequality respectively. These distinct conceptualisations generate three key and overlapping tensions, relating to (i) global versus local priorities, (ii) mitigation and adaptation, and (iii) socio-technical versus socio-political transformations. By highlighting these discursive processes, the results aid our understanding in how mining is made salient in the carbon constrained future, and which actors are likely to benefit and be harmed by the promotion of climate-smart mining.
146

Weekly planning of hydropower in systems with large volumes of varying power generation

Ahlfors, Charlotta January 2022 (has links)
Hydropower is the world’s largest source of renewable electricity generation. Hydropower plants with reservoirs provide flexibility to the power systems. Efficient planning techniques improve the flexibility of the power systems and reduce carbon emissions, which is needed in power systems experiencing a rapid change in balance between power production and consumption. This is due to increasing amount of renewable energy sources, such as wind and solar power. Hydropower plants have low operating costs and are used as base power. This thesis focuses on weekly planning of hydropower in systems with large volumes and varying power generation and a literature review and a maintenance scheduling method are presented. The topic of hydropower planning is well investigated and various research questions have been studied under many years in different countries. Some of the works are summarized and discussed in literature reviews, which are presented in this thesis. First, some reviews are presented, which covers several aspects of hydropower planning. Literature reviews for long term, mid term and short term planning, respectively, are described. Maintenance scheduling in power systems consists of preventive and corrective maintenance. Preventive maintenance is performed at predetermined intervals according to a prescribed criteria. This type of maintenance is important for power producers to avoid loss in electricity production and loss in income. The maintenance scheduling for hydropower plants prevent these phenomena since spill in the reservoirs and wear on the turbines can be avoided. Usually, the maintenance in hydropower plants is performed on the turbines or at the reservoir intake. A deterministic and a stochastic method to solve a mid term maintenance scheduling problem formulated as a Mixed Integer Linear Programming using dynamic programming is presented. The deterministic method works well in terms of computational time and accuracy. The stochastic method compared to the deterministic method yields a slightly better result at the cost of a need for larger computational resources. / Vattenkraft är världens största källa till förnyelsebar elproduktion. Vattenkraftverk med magasin erbjuder flexibilitet till elkraftsystem. Effektiva planeringsmetoder förbättrar flexibiliteten hos kraftsystemen och minskar koldioxidutsläppen, vilket är nödvändigt i kraftsystem som utsätts för snabb förändring med obalans mellan produktion och konsumtion av effekt. Detta beror på ökad andel förnyelsebara energikällor, som vind- och solkraft, i kraftsystemen. Vattenkraftverk har låga driftkostnader och används som baskraft. Den här avhandlingen fokuserar på veckoplanering av vattenkraft i kraftsystem med stora volymer och varierande kraftproduktion, samt en litteraturstudie och en metod för underhållsplanering presenteras.    Ämnet vattenkraftplanering är väl undersökt och varierande forskningsfrågor har studerats under många år i olika länder. En del av arbetena sammanfattas och diskuteras i litteraturstudier, vilka presenteras i den här avhandlingen. Först presenteras några litteraturstudier, som täcker flera aspekter av vattenkraftplanering. Litteraturstudier, för långtids-, medeltidsplanering, respektive korttidsplanering beskrivs.    Underhållsplanering i elkraftsystem består av förebyggande och korrigerande underhåll. Förebyggande underhåll utförs vid förutbestämda intervall enligt förbestämda kriterier. Denna typ av underhåll är viktig för att kraftproducenter ska kunna undvika förlorad elproduktion och förlorad inkomst. Underhållsplaneringen för vattenkraftverk förebygger dessa fenomen, eftersom spill i magasinen och slitage på turbinerna kan undvikas. Vanligen utförs underhållen i vattenkraftverken på turbinerna eller vid intaget i magasinet. En deterministisk metod och en stokastisk metod att lösa ett medeltidsplaneringsproblem, formulerat som ett blandat heltalsprogrammeringsproblem presenteras. Den deterministiska metoden fungerar väl i termer av beräkningstid och noggrannhet. Den stokastiska metoden jämfört med den deterministiska metoden ger ett något bättre resultat dock till priset av ett behov av större datorresurser. / <p>QC 20220920</p>
147

Impact of Different e-Fuels Types on Light Duty Compression Ignition Engine Performance, Emissions and CO2 Life Cycle Analysis

Guzmán Mendoza, María Gabriela 07 March 2024 (has links)
[ES] Los combustibles bajos en carbono (LCF) se evalúan como un sustituto adecuado de los combustibles pesados fósiles actuales para un motor de combustión interna de encendido por compresión (CI ICE) en términos de rendimiento del motor, emisiones contaminantes e impacto ambiental. Los combustibles se evalúan de acuerdo con su factibilidad para sustituir los combustibles actuales del mercado con las alternativas LCF. A través de estudios directos y calibración optimizada específica del combustible, se aprovechan las características de bajas emisiones de los LCF para lograr menos emisiones contaminantes sin sacrificar la eficiencia del motor. La calibración se logra mediante la realización de un diseño de experimentos (DOE) a partir del cual se obtienen modelos para cada combustible, para posteriormente optimizar para bajas emisiones de NOx-hollín. Por último, se compara el impacto tanto de la calibración drop-in como de la calibración optimizada en un análisis de ciclo de vida (LCA) que tiene en cuenta la huella de CO2, así como otras categorías de impacto como la acidificación terrestre, la formación de partículas, el consumo de agua y la formación de ozono. En general, se encontró que los LCF probados pueden ser reemplazos adecuados para los CI ICE tanto en las calibraciones directas como en las optimizadas (aunque con algunas consideraciones de hardware), donde se puede alcanzar un rendimiento del motor similar a las líneas de base diésel actuales con importantes reducciones de contaminantes como NOx y hollín. Y adicionalmente, se comprobó que la proporción de renovabilidad del combustible es altamente beneficiosa para la reducción del impacto ambiental del combustible, donde los combustibles completamente renovables (como el LCD100 probado) podrían tener huellas de CO2 por kilómetro similares a las de los vehículos eléctricos en Europa, asumiendo que las materias primas y la energía para la producción de combustible provienen de fuentes renovables. / [CA] Els combustibles baixos en carboni (LCF) s'avaluen com un reemplaçament adequat dels combustibles pesats fòssils actuals per a un motor de combustió interna d'encesa per compressió (CI ICE) en termes de rendiment del motor, emissions contaminants i impacte ambiental. Els combustibles s'avaluen segons la seva viabilitat per substituir els combustibles actuals del mercat per les alternatives LCF. Mitjançant estudis d'abandonament i calibratge optimitzat específic del combustible, s'exploten les característiques de baixes emissions dels LCF per aconseguir emissions menys contaminants sense sacrificar l'eficiència del motor. El calibratge s'aconsegueix mitjançant la realització d'un disseny d'experiments (DOE) a partir del qual s'obtenen models per a cada combustible, per posteriorment optimitzar per a baixes emissions de NOx-sutge. Finalment, es compara l'impacte tant de la caiguda com del calibratge optimitzat en una anàlisi de cicle de vida (LCA) que considera la petjada de CO2, així com altres categories d'impacte com l'acidificació terrestre, la formació de partícules en suspensió, el consum d'aigua i la formació d'ozó. En general, es va trobar que els LCF provats poden ser reemplaçaments adequats per als CI ICE tant en les calibracions d'entrada com optimitzades (encara que amb algunes consideracions de maquinari), on es pot assolir un rendiment del motor similar a les línies de base dièsel actuals amb reduccions importants de contaminants com el NOx i el sutge. I addicionalment, es va comprovar que la proporció de renovable del combustible és altament beneficiosa per a la reducció de l'impacte ambiental del combustible, on els combustibles completament renovables (com el provat LCD100) podrien tenir petjades de CO2 per quilòmetre similars a les dels vehicles elèctrics a Europa, assumint que les matèries primeres i l'energia per a la producció de combustible provenen de fonts renovables. / [EN] Low carbon fuels (LCFs) are evaluated as a suitable replacement for current fossil heavy fuels for a compression ignition internal combustion engine (CI ICE) in terms of engine performance, pollutant emissions and environmental impact. The fuels are evaluated according to their feasibility to substitute current market fuels with the LCF alternatives. Through drop-in studies and fuel-specific optimized calibration, the low emission characteristics of the LCFs to achieve fewer polluting emissions without sacrificing the engine efficiency are exploited. The calibration is achieved by the realization of a design of experiments (DOE) from which models are obtained for each fuel, to be later optimized for low NOx-soot emissions. Finally, the impact of both the drop-in and optimized calibration are compared in a life cycle analysis (LCA) that considers the CO2 footprint, as well as other impact categories such as terrestrial acidification, particulate matter formation, water consumption and ozone formation. Overall, it was found that the tested LCFs can be suitable replacements for CI ICEs in both the drop-in and optimized calibrations (albeit with some hardware considerations), where engine performance similar to current diesel baselines can be reached with important reductions in pollutants like NOx and soot. And additionally, it was verified that the renewability proportion of the fuel is highly beneficial to the reduction of the environmental impact of the fuel, where completely renewable fuels (like the tested LCD100) could have CO2 footprints by kilometer similar to those of electric vehicles in Europe, assuming that raw materials and energy for the fuel production come from renewable sources. / This doctoral thesis has been partially supported by the Conselleria d'Innovació, Universitats, Ciència i Societat Digital de la Generalitat Valenciana through the predoctoral contract (ACIF/2021/200). / Guzmán Mendoza, MG. (2024). Impact of Different e-Fuels Types on Light Duty Compression Ignition Engine Performance, Emissions and CO2 Life Cycle Analysis [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/203090
148

Optimal ranking and sequencing of non-domestic building energy retrofit options for greenhouse gas emissions reduction

Ibn-Mohammed, Taofeeq January 2014 (has links)
Whether it is based on current emissions data or future projections of further growth, the building sector currently represent the largest and singular most important contributor to greenhouse gas (GHG) emissions globally. This notion is also supported by the Intergovernmental Panel on Climate Change based on projection scenarios for 2030 that emissions from buildings will be responsible for about one-third of total global emissions. As such, improving the energy efficiency of buildings has become a top priority worldwide. A significant majority of buildings that exist now will still exist in 2030 and beyond; therefore the greatest energy savings and carbon footprint reductions can be made through retrofit of existing buildings. A wide range of retrofit options are readily available, but methods to identify optimal solutions for a particular abatement project still constitute a major technical challenge. Investments in building energy retrofit technologies usually involve decision-making processes targeted at reducing operational energy consumption and maintenance bills. For this reason, retrofit decisions by building stakeholders are typically driven by financial considerations. However, recent trends towards environmentally conscious and resource-efficient design and retrofit have focused on the environmental merits of these options, emphasising a lifecycle approach to emissions reduction. Retrofit options available for energy savings have different performance characteristics and building stakeholders are required to establish an optimal solution, where competing objectives such as financial costs, energy consumption and environmental performance are taken into account. These key performance parameters cannot be easily quantified and compared by building stakeholders since they lack the resources to perform an effective decision analysis. In part, this is due to the inadequacy of existing methods to assess and compare performance indicators. Current methods to quantify these parameters are considered in isolation when making decisions about energy conservation in buildings. To effectively manage the reduction of lifecycle environmental impacts, it is necessary to link financial cost with both operational and embodied emissions. This thesis presents a novel deterministic decision support system (DSS) for the evaluation of economically and environmentally optimal retrofit of non-domestic buildings. The DSS integrates the key variables of economic and net environmental benefits to produce optimal decisions. These variables are used within an optimisation scheme that consists of integrated modules for data input, sensitivity analysis and takes into account the use of a set of retrofit options that satisfies a range of criteria (environmental, demand, cost and resource constraints); hierarchical course of action; and the evaluations of ‘best’ case scenario based on marginal abatement cost methods and Pareto optimisation. The steps involved in the system development are presented and its usefulness is evaluated using case study applications. The results of the applications are analysed and presented, verifying the feasibility of the DSS, whilst encouraging further improvements and extensions. The usefulness of the DSS as a tool for policy formulation and developments that can trigger innovations in retrofit product development processes and sustainable business models are also discussed. The methodology developed provides stakeholders with an efficient and reliable decision process that is informed by both environmental and financial considerations. Overall, the development of the DSS which takes a whole-life CO2 emission accounting framework and an economic assessment view-point, successfully demonstrates how value is delivered across different parts of the techno-economic system, especially as it pertains to financial gains, embodied and operational emissions reduction potential.
149

ATRIBUTOS DE PLANTAS E DE FERTILIDADE DO SOLO SOB ADUBAÇÃO POTÁSSICA EM SISTEMA INTEGRADO DE PRODUÇÃO AGROPECUÁRIA

Schneider, Thays 31 May 2016 (has links)
Made available in DSpace on 2017-07-25T19:30:59Z (GMT). No. of bitstreams: 1 Thays Schneider.pdf: 1808530 bytes, checksum: 30d501a211bd2062abba571e9202b79e (MD5) Previous issue date: 2016-05-31 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The Integrated Crop-Livestock System (ICLS) is in a form of integrated production, which achieve a higher environmental, economic and social sustainability. Because of the efficient nutrient cycling and biodiversity of crops, the system combines food production with environmental conservation. The lack of research in the context of the potassium (K) dynamic in subtropical soils under ICLS and how the shading provided by the arboreal component alters the production, determined the focus of this research. The main objective of this project consists in evaluating the effects of shade (provided by eucalyptus) on the attributes of plants and soil fertility under conditions of K rates (0, 100, 200 and 300 kg ha-1 yr-1 K2O) applied on the soil surface in the entire area. Two experiments are being conducted simultaneously in an Typic Hapludox on a model farm of the Agronomic Institute of Paraná (IAPAR), Ponta Grossa (PR). The experiment employs an experimental design in randomized complete block with split plots and three replications. The plots (4 x 24 m) consists of annual plants (corn, oat and soybean) and the distances considered in relation to eucalyptus (shading effect) were: 0-4, 4-8, 8-12 and 12-16 m. The subplots (4 x 6 m) receive doses (0, 100, 200 and 300 kg ha-1 yr-1 of K2O) K (as potassium chloride), at the soil surface at the time of seeding culture of autumn-winter (oat) and at seeding of the summer crop (corn and soybeans). The second experiment was also a randomized complete block design with split plot and three replications. The plots were characterized by rows of eucalyptus and subplots doses of K (similar to the first experiment). In the maize crop (2012/13 and 2014/15) and soybean (2013/14) were evaluated nutritional status (for macronutrients) and grain maize yield (GYM and GYS). During oat growing (2013 and 2014) were evaluated the dry matter yield (DMY), height and macronutrient accumulation. The evaluation of nutritional status of eucalyptus was conducted in the summer (2013/14), and the nutrients in the leaf litter under the canopy. Soil samples of layers 0-5, 5-10, 10-15, 15-20, 20-40 and 40-60 cm were performed in both experiments at 6, 12 and 30 months after the start of the experiment (Sep / 2012). After that, was determined pH concentration, H + Al, C, Ca, Mg, K, Al, CEC and effective CEC (ECEC), base saturation (%) and aluminum (m%) and the percentage of K, Ca and Mg in the effective CEC. In general, higher concentrations of cations was observed in less shaded transects, which favored the largest DMY for oats/2014 (2218.83 kg ha-1) and GYM (10,470.1 kg ha-1 in 2012/13 and 8742, 5 kg ha-1 in 2014/15) and GYS (1989.0 kg ha-1). Moreover, high concentrations of Ca and Mg were detected in the whole profile favoring saturation in these ECEC in second experiment. Leaching was not observed in profile in the second experiment. The concentration of N, P and K in shoots of eucalypt was within the proper range, but the opposite was observed for Ca, Mg and S. The reduction of the concentration of N, P, K, Mg and S in the litter, may indicate a biochemical decomposition. However, the concentration of Ca in the litter, suggests the influence of biogeochemical cycling. K doses did not affect the production of eucalyptus at 8 years. / O sistema integrado de produção agropecuária (SIPA) consiste em uma das formas de produção integrada, o qual busca maior sustentabilidade ambiental, econômica e social. Em razão da eficiente ciclagem de nutrientes e biodiversidade de culturas, o sistema alia a produção de alimentos com a conservação do meio ambiente. A ausência de pesquisa no âmbito da dinâmica do potássio (K) em solos subtropicais sob SIPA e como a restrição de radiação proporcionado pelo componente arbóreo altera a produção, determinou o foco desta pesquisa. O objetivo deste trabalho foi avaliar os efeitos da restrição de radiação (proporcionado pelo eucalipto) sobre os atributos de plantas e de fertilidade do solo, em condições de doses de K (0, 100, 200 e 300 kg ha-1 ano-1 de K2O) aplicadas na superfície do solo, em área total. Dois experimentos paralelos foram implantados (em setembro/2012) em um Latossolo Vermelho na Fazenda Modelo, município de Ponta Grossa (PR). O primeiro experimento empregou delineamento experimental em blocos completos casualizados com parcelas subdivididas e três repetições. As parcelas (4 x 24 m) consistem das plantas anuais (milho, aveia branca e soja) e as distâncias consideradas em relação ao eucalipto (efeito da restrição de radiação) foram: 0-4, 4-8, 8-12 e 12-16 m. As subparcelas (4 x 6 m) recebem as doses (0, 100, 200 e 300 kg ha-1 ano-1 de K2O) de K (na forma de cloreto de potássio), na superfície do solo, por ocasião da semeadura da cultura de inverno (aveia branca, para produção de forragem) e na semeadura da cultura de verão (milho e soja, para produção de grãos). O segundo experimento também foi em blocos completos casualizados com parcela subdividida e três repetições. As parcelas foram caracterizadas por renques de eucalipto e as subparcelas as doses de K (similarmente ao primeiro experimento). Nas culturas de milho (2012/13 e 2014/15) e soja (2013/14) foram avaliados o estado nutricional (para os macronutrientes) e o rendimento de grãos (RGM e RGS). Durante o cultivo da aveia branca (2013 e 2014), foram avaliados o rendimento de massa seca (RMS), altura e acúmulo de macronutrientes. A avaliação do estado nutricional do eucalipto foi realizada no verão (2013/14), bem como os nutrientes na serapilheira sob a copa. Coletas de solo das camadas 0-5, 5-10, 10-15, 15-20, 20-40 e 40-60 cm foram realizadas em ambos os experimentos aos 6, 12 e 30 meses após o início do experimento (Set/2012), visando determinar as concentrações de pH, H+Al, C, Ca, Mg, K, Al, CTC potencial (CTC) e efetiva (CTCe), saturação de bases (V%) e de alumínio (m%) e a porcentagem de K, Ca e Mg na CTC efetiva. Maior influência da restrição de radiação em relação às doses de K foi observado para o experimento 1. Redução do K trocável foi observado aos 30 meses, o que reduziu a 1% a saturação de K na CTCe. Em geral, maiores concentrações de cátions foram observadas em transectos menos sombreados, o que favoreceu o maior RMS para aveia/2014 (2218,83 kg ha-1) e RGM (10470,1 kg ha-1 em 2012/13 e 8742,5 kg ha-1em 2014/15) e RGS (1989,0 kg ha-1). Por outro lado, concentrações altas de Ca e Mg foram verificadas em todo perfil, favorecendo a saturação destes na CTCe no segundo experimento. Lixiviação não foi observada no perfil no segundo experimento. As concentrações de N, P e K na parte aérea do eucalipto esteve dentro da faixa adequada, contudo concentrações baixas foram observados para Ca, Mg e S. A redução da concentração de N, P, K, Mg e S na serapilheira, pode indicar decomposição bioquímica. Todavia, aumento da concentração de Ca na serapilheira sugere a influência da ciclagem biogeoquímica. Doses de K não afetaram a produção do eucalipto aos 8 anos.
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L’énergie solaire pour la production d’électricité au Maghreb : transition énergétique et jeux d’échelles / Using solar energy for power generation in the Maghreb : energy transition and scales

Benalouache, Nadia 30 June 2017 (has links)
La transition énergétique « bas carbone » au Maghreb, analysée sous l’angle du déploiement de l’énergie solaire pour la production d’électricité, est appréhendée dans un double contexte euro-méditerranéen et national. Elle est notamment le fruit de projets imaginés par des structures supranationales et décidés au plus haut niveau des États. À l’échelle euro-méditerranéenne, des initiatives ont été mises en place pour appuyer le développement à grande échelle de l’énergie solaire, qu’elles émanent de dispositifs intergouvernementaux (Plan Solaire Méditerranéen en 2008) et de consortia industriels privés (Desertec Industrial Initiative, Medgrid en 2009). À l’échelle nationale, les trois pays du Maghreb (Algérie, Maroc, Tunisie) ont formulé, surtout depuis 2009, des politiques de développement des énergies renouvelables, et élaboré, pour leur mise en œuvre, des plans et programmes nationaux. L’objet de cette thèse est d’analyser la mise en œuvre de la transition énergétique « bas carbone » au Maghreb et d’en montrer les implications spatiales et relationnelles aux échelles euro-méditerranéenne et nationale. Ainsi, nous montrons en quoi l’électricité contribue à redéfinir la mise en réseau des espaces régionaux et dans quelles mesures la diffusion des technologies solaires participe à redessiner la géographie de l’électricité au Maghreb. L’objet technique (infrastructure de réseau et unité de production d’électricité à partir de l’énergie solaire) est appréhendé à partir d’une approche systémique, à l’interface des sphères spatiale, politique et économique et sociale. / The « low carbon » transition in the Maghreb, analyzed with a focus on the deployment of solar energy for electricity generation, is considered in both a Euro-Mediterranean and national context. This transition is the result of projects that were designed by supranational organizations and agreed on at the highest level. On a Euro-Mediterranean level, initiatives were implemented to support a large scale development of solar energy, whether it be at an intergovernmental level (Mediterranean Solar Plan, 2008), by private industrial consortia (Desertec Industrial Initiative, Medgrid 2009). At national level, the three Maghreb countries (Algeria, Morocco, Tunisia), have formulated explicit renewables development policies, (especially since 2009), and established national plans and programs (Moroccan Solar Plan, Tunisian Solar Plan, National Renewable and Efficiency Energy Program in Algeria). The purpose of this thesis is to explore the implementation of the « low carbon » transition in the Maghreb and show what spatial and relational implications it had both at European and national level. Thus, we explain how electrical energy contributes to redefine how regional areas connect and to what extent the implementation of solar technologies helps reshape the geography of electrical energy in the Maghreb. The technical aspect (network infrastructure and electricity production unit by solar energy) will be studied following a systemic approach, at the crossroads of spatial, social, political and economical spheres. / الملخص تسعى الأطروحة إ لى تحليل الانتقال نحو الطاقات الىتجددة وخاصة الشمسية بأقطار الىغرب العربي من خلالإطارين : إطارأورو - متوسطي و إطار قطري مح . يبدو الانتقال الطاقي وكأنه نتاج لىشاريع أعدتها هياكل فوق قطرية .ك ما أن إقرارها تم لى تموضع مبادرات تهدف إ لى ، أ ع ا لى ستويات السياسية . فع الىستوى ا لا ورو - متوسطي استعمال الطاقة الشمسية ع نطاق واسع وهذه الىبادرات ناشئةعن ترتيبات ب ين .(2008 - خطة الطاقة الشمسية الىتوسطية 2009 الحكومات ) مبادرة ديزرتاك اهتمت الأطروحة بأقطار الىغرب العربي الثلاثة )تونس - الجزائر - الىغرب ( مجسدة لى ثلاثة برامج كلى ى : خطة الطاقة الشمسية الىغربية، الىخطط الشم التون ، ا ل لىنامج الوطني للطاقة الىتجددة وكفاءة الطاقة لى الجزائر . إن الغرض من الأطروحة هو كذلك تحليل الانتقال الطاقي بشمال إفريقيا وإبراز أثارها الىجالية والعلائقية ع الىستوىا لا ورو - متوسطي و ع الىستويات الوطنية، ك ما نسعى إ لى إبراز كيفة مساعدة الطاقة الشمسية ع إعادة تعريف الشبكات غ الىستوى الإقليمي وكيف أن إعادة توزيع تكنولوجيا الطاقة الشمسية تشارك لى إعادة رسم جغرافية الكهرباء بشمال إفريقيا .

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