5,909 research outputs found

    A cellular automaton for the factor of safety field in landslides modeling

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    Landslide inventories show that the statistical distribution of the area of recorded events is well described by a power law over a range of decades. To understand these distributions, we consider a cellular automaton to model a time and position dependent factor of safety. The model is able to reproduce the complex structure of landslide distribution, as experimentally reported. In particular, we investigate the role of the rate of change of the system dynamical variables, induced by an external drive, on landslide modeling and its implications on hazard assessment. As the rate is increased, the model has a crossover from a critical regime with power-laws to non power-law behaviors. We suggest that the detection of patterns of correlated domains in monitored regions can be crucial to identify the response of the system to perturbations, i.e., for hazard assessment.Comment: 4 pages, 3 figure

    Seismic resilience assessment of Small Modular Reactors by a Three-loop Monte Carlo Simulation

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    We develop a three-loop Monte Carlo Simulation (MCS) framework for the seismic resilience assessment of Small Modular Reactors (SMRs), embedding Probabilistic Seismic Hazard Analysis (PSHA), seismic fragility evaluation and multiple SMR units accident sequence analysis. A set of metrics are computed to capture different aspects of SMR resilience to earthquakes, specifically the ability to withstand seismic disruption, mitigate consequences and restore normal operation. The MCS framework allows accounting for the aleatory and epistemic uncertainties of the PSHA and fragility parameters. An application is given with regards to an advanced Nuclear Power Plant (aNPP) consisting of four reactor units of NuScale SMR design. A comparison is made to a conventional NPP (cNPP), i.e., a typical large reactor of equivalent generation capacity. Both plants are fictitiously located on the Garigliano nuclear site (southern Italy). The results show that resilient features of SMRs overcome cNPPs in terms of post-accident scenario mitigation and restoration capabilities

    Probabilistic scenario analysis of integrated road-power infrastructures with hybrid fleets of EVs and ICVs

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    Electric Vehicles (EVs) are key contributors to the reduction of CO2 emissions. However, reliance on EVs must come with the guarantee that the integrated road-power infrastructure is capable of providing adequate mobility serviceability, even in case of disruption due to accidents or disturbances due to traffic jams. In this paper, we propose a probabilistic scenario analysis framework to quantify service losses in terms of delays that vehicles (both EVs and Internal Combustion Vehicles (ICVs)) may incur due to different car accident scenarios. The framework is based on modelling the System of Systems (SoS) comprised by road network, electric power system and vehicles, with graph theory and Finite State Machines (FSMs), respectively, and then embedding the model within a probabilistic scenario analysis, wherein meaningful disruption scenarios are sampled, service losses are measured (specifically as the ratio between the increase in travel time spent along the origin-destination routes on the road network following a disruption, and the corresponding travel time in nominal traffic conditions), and the economic losses and transport reliability of the infrastructure are assessed. To exemplify the application of the framework, we consider a benchmark road-power infrastructure in New York state travelled by a mixed fleet of EVs and ICVs, with different EVs penetration levels and under car accidental scenarios of different magnitudes. By using the insightful graphical representation of the results in terms of traffic volume across different road sections, the framework allows comparing alternative road-power infrastructure designs (e.g., critical roads, optimal gas and charging station locations, power network structure and topology, ...) with respect to travel times, economic service losses and transport reliability considering different nominal and disruption scenarios under different EVs penetration levels service

    Propiedades de transporte de hormigón con cemento puzolánico

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    Existen estructuras emplazadas en medios agresivos que requieren una adecuada resistencia al ingreso de agentes agresivos para completar su vida útil con un nivel aceptable de serviciabilidad. Adicionalmente a las buenas prácticas constructivas, resulta necesario trabajar sobre el diseño de la mezcla de hormigón, de manera de lograr óptimos resultados a un costo menor. El cemento portland puzolánico (CPP) aparece como una de las opciones más apropiadas conjugando durabilidad y economía. El presente trabajo tiene como objetivo evaluar distintas propiedades relacionadas con la penetrabilidad de agentes externos a la estructura porosa de hormigones de distinto nivel resistente elaborados con cemento CPP. Se utilizaron método de ensayo para la evaluación del transporte de líquidos y gases, tales como el de penetración de agua a presión, absorción capilar, permeabilidad al aire y migración de cloruro. Los resultados obtenidos a 28 días, mostraron efectos sumamente positivos de la acción puzolánica de la adición como reemplazo parcial del clínquer, resaltando la potencialidad del uso del cemento CPP para ambientes agresivos.Concrete structures located in aggressive environments must have enough resistance against the ingress of aggressive agents so that they can achieve their service life with acceptable serviceability. In addition to suitable construction practices, concrete mix design must be studied to achieve the best results at low cost. Pozzolanic Portland cement (PPC) seems one of the most appropriate options, which combines durability and economy. This paper aims to evaluate properties related to the penetration of external agents through the pore structure of PPC concrete with dissimilar strength levels. Liquid and gas transport was evaluated by tests methods such as water penetration under pressure, sorptivity, air permeability and chloride migration. At 28 days, the obtained results showed very positive pozzolanic effect of the admixture as partial replacement of clinker, which shows the potentiality of using PPC for aggressive environments

    Money management and entrepreneurial training in microfinance: impact on beneficiaries and institutions

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    This study uses a randomized control trial to evaluate the outcome of integrating money management and entrepreneurial training into a microcredit program in India. We find positive and significant effects on clients\u2019 financial management skills and entrepreneurship abilities, particularly for clients with higher human capital, or more diligent, or having an entrepreneurial idea, and an increase in initiative and self-confidence. Effects appear stronger for clients obliged to attend the training course or more interested in attending it. By considering missed or delayed repayments reduction we assess the benefits of the training provided and of extending it for the institution
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