479 research outputs found

    Pathwise uniqueness and continuous dependence for SDEs with nonregular drift

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    A new proof of a pathwise uniqueness result of Krylov and R\"{o}ckner is given. It concerns SDEs with drift having only certain integrability properties. In spite of the poor regularity of the drift, pathwise continuous dependence on initial conditions may be obtained, by means of this new proof. The proof is formulated in such a way to show that the only major tool is a good regularity theory for the heat equation forced by a function with the same regularity of the drift

    Making Something From Nothing: Exploring Food, Transition, and Globalization in Post-Socialist Poland

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    This thesis explores post-socialist cultural practices, globalization, and conceptions of modernity through the lens of food. Socialist influence remains visible in Poland’s collective memory, architecture, symbols, political and economic systems, and, as examined in this thesis, foodways. Linking macroeconomic and political upheaval with multigenerational ethnography, this project examines how everyday foodways have transitioned in Poland post-1989. Under socialism, chronic food shortages prompted Polish cooks to learn “…jak zrobić coś z niczego” (“…how to make something from nothing”). Ethnography with a typical middle-class Polish family reveals that they have incorporated new ingredients, recipes, and cuisines into their repertoire as the country has become more integrated into the global market. They retain, however, food practices that challenge Western conceptions of modernity, including growing home gardens, home-distilling liqueurs, and reviving regional culinary traditions. Combining ethnographic fieldwork in Poland with archival research using Przyjaciółka magazine, I explore perceptions and realities of life in the Polska Rzeczpospolita Ludowa (Polish People’s Republic) and the increasingly globalized orientation of the current generation

    A genetic algorithm-assisted semi-adaptive MMSE multi-user detection for MC-CDMA mobile communication systems

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    In this work, a novel Minimum-Mean Squared-Error (MMSE) multi-user detector is proposed for MC-CDMA transmission systems working over mobile radio channels characterized by time-varying multipath fading. The proposed MUD algorithm is based on a Genetic Algorithm (GA)-assisted per-carrier MMSE criterion. The GA block works in two successive steps: a training-aided step aimed at computing the optimal receiver weights using a very short training sequence, and a decision-directed step aimed at dynamically updating the weights vector during a channel coherence period. Numerical results evidenced BER performances almost coincident with ones yielded by ideal MMSE-MUD based on the perfect knowledge of channel impulse response. The proposed GA-assisted MMSE-MUD clearly outperforms state-of-the-art adaptive MMSE receivers based on deterministic gradient algorithms, especially for high number of transmitting users

    Noise Prevents Singularities in Linear Transport Equations

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    A stochastic linear transport equation with multiplicative noise is considered and the question of no-blow-up is investigated. The drift is assumed only integrable to a certain power. Opposite to the deterministic case where smooth initial conditions may develop discontinuities, we prove that a certain Sobolev degree of regularity is maintained, which implies H\"older continuity of solutions. The proof is based on a careful analysis of the associated stochastic flow of characteristics

    Experimental test of nonlocal causality.

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    Explaining observations in terms of causes and effects is central to empirical science. However, correlations between entangled quantum particles seem to defy such an explanation. This implies that some of the fundamental assumptions of causal explanations have to give way. We consider a relaxation of one of these assumptions, Bell's local causality, by allowing outcome dependence: a direct causal influence between the outcomes of measurements of remote parties. We use interventional data from a photonic experiment to bound the strength of this causal influence in a two-party Bell scenario, and observational data from a Bell-type inequality test for the considered models. Our results demonstrate the incompatibility of quantum mechanics with a broad class of nonlocal causal models, which includes Bell-local models as a special case. Recovering a classical causal picture of quantum correlations thus requires an even more radical modification of our classical notion of cause and effect

    Effects of post-printing heat treatment on microstructure, corrosion and wet wear behavior of CoCrW alloy produced by L-PBF process

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    CoCr alloys are widely used as human implants because of both their superior corrosion resistance and superior mechanical properties (fatigue, wear resistance, etc.) respect to other metal alloys used in biomedical field. In particular, CoCrW alloys are used mainly to produce dental implants. In this study, the effects of thermal treatment on the corrosion resistance and wet wear resistance of CoCrW alloys produced via Laser-Powder Bed Fusion (L-PBF) were investigated, and the corrosion resistance and wet wear resistance of the L-PBF specimens were compared with those of the specimens obtained after forging. The heat treatment involved the solubilization of the alloy at 1150 °C in an Ar-saturated atmosphere, followed by furnace cooling. A detailed microstructural characterization of the L-PBF specimens was carried out using a light microscope and a scanning electron microscope in both the horizontal and vertical growth directions. Scanning Kelvin probe measurements were performed on the heat-treated specimens obtained by three-dimensional printing and forging. The void contents of the specimens were evaluated using the Archimedes’ method and image analysis. Vickers (HV2) hardness measurements were performed to evaluate the mechanical properties of the specimens. The corrosion properties of the specimens were evaluated by carrying out potentiodynamic tests in two different corrosive media (aqueous solution (9 g/L NaCl) at pH = 2 and 7). The corroded areas of the specimens were then examined using scanning electron microscopy (SEM). Finally, tribological tests were performed using the pin (Ti counter material)-on-flat configuration under dry and wet conditions, using the same corrosive environments as those used in the potentiodynamic tests and two different stroke lengths. The worn samples were characterized using SEM to investigate their wear mechanisms, and a stylus profilometer was used to determine the wear rates of the materials. The experimental results showed that the additively manufactured CoCrW L-PBF alloy had higher corrosion resistance than the wrought material. In addition, the additively manufactured material showed better dry and wet wear performances than the wrought material. Nevertheless, the heat treatment did not affect the properties evaluated in this study

    Bombeamento de água no meio rural, análise econômica de duas configurações fotovoltaicas e uma elétrica convencional

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    Apesar do grande potencial de aplicação, a tecnologia de bombeamento fotovoltaico não está mais disseminada por requerer um grande aporte de investimento inicial, ainda que seus custos de operação sejam reduzidos por não depender da compra de combustível, como é o caso dos sistemas com energia fóssil, ou do pagamento de tarifa elétrica, como é o caso dos sistemas elétricos convencionais. Este trabalho apresenta uma avaliação econômica de duas configurações de sistemas fotovoltaicos de bombeamento e a respectiva comparação com a alternativa de atendimento com a rede elétrica convencional. Através dos resultados e premissas de um estudo de caso no estado de São Paulo, pôde-se constatar que para um único atendimento, nas potências necessárias, que são usualmente baixas, a opção fotovoltaica é mais competitiva para distâncias superiores a 1 km da rede.In spite of the great potential of application, the photovoltaic pumping technology is not more disseminated by requesting a great contribution of initial investment, although its operation costs are reduced for not depending of the purchase of fuel, as it is the case of the systems with fossil energy, or of the payment of electric tariff, as it is the case of the conventional electric systems. This work presents an economic evaluation of two configurations of photovoltaic pumping systems and the respective comparison with the attendance alternative with the conventional electric grid. Through the results and premises of a case study in the state of São Paulo, it could be verified that for an only attendance, in the necessary potencies, that they are usually low, the option photovoltaic is more competitive for distances higher than 1 km of the grid.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

    Bombeamento de água no meio rural, análise econômica de duas configurações fotovoltaicas e uma elétrica convencional

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    Apesar do grande potencial de aplicação, a tecnologia de bombeamento fotovoltaico não está mais disseminada por requerer um grande aporte de investimento inicial, ainda que seus custos de operação sejam reduzidos por não depender da compra de combustível, como é o caso dos sistemas com energia fóssil, ou do pagamento de tarifa elétrica, como é o caso dos sistemas elétricos convencionais. Este trabalho apresenta uma avaliação econômica de duas configurações de sistemas fotovoltaicos de bombeamento e a respectiva comparação com a alternativa de atendimento com a rede elétrica convencional. Através dos resultados e premissas de um estudo de caso no estado de São Paulo, pôde-se constatar que para um único atendimento, nas potências necessárias, que são usualmente baixas, a opção fotovoltaica é mais competitiva para distâncias superiores a 1 km da rede.In spite of the great potential of application, the photovoltaic pumping technology is not more disseminated by requesting a great contribution of initial investment, although its operation costs are reduced for not depending of the purchase of fuel, as it is the case of the systems with fossil energy, or of the payment of electric tariff, as it is the case of the conventional electric systems. This work presents an economic evaluation of two configurations of photovoltaic pumping systems and the respective comparison with the attendance alternative with the conventional electric grid. Through the results and premises of a case study in the state of São Paulo, it could be verified that for an only attendance, in the necessary potencies, that they are usually low, the option photovoltaic is more competitive for distances higher than 1 km of the grid.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

    Bombeamento de água no meio rural, análise econômica de duas configurações fotovoltaicas e uma elétrica convencional

    Get PDF
    Apesar do grande potencial de aplicação, a tecnologia de bombeamento fotovoltaico não está mais disseminada por requerer um grande aporte de investimento inicial, ainda que seus custos de operação sejam reduzidos por não depender da compra de combustível, como é o caso dos sistemas com energia fóssil, ou do pagamento de tarifa elétrica, como é o caso dos sistemas elétricos convencionais. Este trabalho apresenta uma avaliação econômica de duas configurações de sistemas fotovoltaicos de bombeamento e a respectiva comparação com a alternativa de atendimento com a rede elétrica convencional. Através dos resultados e premissas de um estudo de caso no estado de São Paulo, pôde-se constatar que para um único atendimento, nas potências necessárias, que são usualmente baixas, a opção fotovoltaica é mais competitiva para distâncias superiores a 1 km da rede.In spite of the great potential of application, the photovoltaic pumping technology is not more disseminated by requesting a great contribution of initial investment, although its operation costs are reduced for not depending of the purchase of fuel, as it is the case of the systems with fossil energy, or of the payment of electric tariff, as it is the case of the conventional electric systems. This work presents an economic evaluation of two configurations of photovoltaic pumping systems and the respective comparison with the attendance alternative with the conventional electric grid. Through the results and premises of a case study in the state of São Paulo, it could be verified that for an only attendance, in the necessary potencies, that they are usually low, the option photovoltaic is more competitive for distances higher than 1 km of the grid.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES
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