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Numerical simulation of mud-flows impacting structures

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Journal of Mountain Science 2019年第2期16卷 364-382页

作者： GRECO Massimo DI CRISTO Cristiana IERVOLINO Michele vacca andrea DICEA Università di Napoli Federico II DI Università della Campania Luigi Vanvitelli

The study of the interaction of mud-flows with obstacles is important to define inundation zones in urban areas and to design the possible structural countermeasures. The paper numerically investigates the impact of a mud-flow on rigid obstacles to evaluate the force acting on them using two different depth-integrated theoretical models, Single-Phase Model(SPM) and Two-Phase Model(TPM), to compare their performance and limits. In the first one the water-sediment mixture is represented as a homogeneous continuum described by a shearthinning power-law rheology. Alternatively, the twophase model proposed by Di Cristo et al in 2016 is used, which separately accounts for the liquid and solid phases. The considered test cases are represented by a 1D landslide flowing on a steep slope impacting on a rigid wall and a 2D mud dam-break flowing on a horizontal bottom in presence of single and multiple rigid obstacles. In the 1D test case, characterized by a very steep slope, the Two-Phase Model predicts the separation between the two phases with a significant longitudinal variation of the solid concentration. In this case the results indicate appreciable differences between the two models in the estimation of both the wave celerity and the magnitude of the impact, with an overestimation of the peak force when using the Single-Phase Model. In the 2D test-cases, where the liquid and solid phases remain mixed, even if the flow fields predicted by the two models present some differences, the essential features of the interaction with the obstacles, along with the maximum impact force, are comparable.

关键词： Mud-Flow Impact force Two-phase model Power-law

A two-phase model for fast geomorphic shallow flows

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International Journal of Sediment Research 2012年第4期27卷 409-425页

作者： Massimo GRECO Michele IERVOLINO Angelo LEOPARDI andrea vacca Dipartimento di Ingegneria Idraulica Geotecnica ed Ambientale-Universita di Napoli “Federico Ⅱ”via Claudio 21-80125 NapoliITALY Prof. Dipartimento di Ingegneria Civile e Meccanica-Universita di Cassino e del Lazio Meridionale via Di Biasio 43-03043 Cassino(FR)ITALY Assis.Prof.Dr. 4. Dipartimento di Ingegneria Civile-Seconda Universita di Napolivia Roma 29-81031 Aversa(CE)ITALY Assoc.Prof.Dr. Dipartimento di Ingegneria Civile-Seconda Universita di Napoli via Roma 29-81031 Aversa(CE)ITALY Assis.Prof.Dr.

The paper introduces a 2D shallow water model based on a two-phase formulation for the analysis of fast geomorphic transients occurring in the context of river *** and momentum conservation principles are separately imposed for both *** model naturally accounts for non-equilibrium solid transport,since neither instantaneous adaptation hypothesis nor any lag equation is employed to represent sediment *** hyperbolic character of the proposed model is shown to be preserved independently on the flow *** from numerical simulations of both 1D and 2D test-cases are compared with literature experimental data and with available numerical solutions.

关键词： Morphodynamic model Non-equilibrium sediment transport Two-phase shallow-water model Eigenvalues analysis Dam-break flows

Spatio-temporal coupled mode theory for nonlocal metasurfaces

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Light(Science & Applications) 2024年第2期13卷 267-282页

作者： Adam Overvig Sander A.Mann andrea Alù Photonics Initiative Advanced Science Research CenterCity University of New YorkNew YorkNY10031USA Physics Program Graduate Center of the City University of New YorkNew YorkNY10016USA

Diffractive nonlocal metasurfaces have recently opened a broad range of exciting developments in nanophotonics research and applications,leveraging spatially extended—yet locally patterned—resonant modes to control light with new degrees of *** conventional grating responses are elegantly captured by temporal coupled mode theory,current approaches are not well equipped to capture the arbitrary spatial response observed in the nascent field of nonlocal ***,we introduce spatio-temporal coupled mode theory(STCMT),capable of elegantly capturing the key features of the resonant response of wavefront-shaping nonlocal *** framework can quantitatively guide nonlocal metasurface design while maintaining compatibility with local metasurface frameworks,making it a powerful tool to rationally design and optimize a broad class of ultrathin optical *** validate this STCMT framework against full-wave simulations of various nonlocal metasurfaces,demonstrating that this tool offers a powerful semi-analytical framework to understand and model the physics and functionality of these devices,without the need for computationally intense full-wave *** also discuss how this model may shed physical insights into nonlocal phenomena in photonics and the functionality of the resulting *** a relevant example,we showcase STCMT’s flexibility by applying it to study and rapidly prototype nonlocal metasurfaces that spatially shape thermal emission.

关键词： theory resonant spatially

A method to perform prognostics in electro-hydraulic machines: the case of an independent metering controlled hydraulic crane

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International Journal of Hydromechatronics 2018年第2期1卷 2-2页

作者： Yuri Ghini andrea vacca Purdue Univ Maha Fluid Power Res Ctr W Lafayette IN 47907 USA

Remaining useful life (RUL) estimation is a topic that has gained more and more attention in the field of fluid power systems, thanks to the tremendous potentials shown for improving safety and reduced production losses. However, many challenges related to RUL estimation are not solved yet, mainly connected to the definition of the health status of each component. A prognostic method based on a data-driven methodology for hydraulic systems is here proposed to estimate the percentage of life already spent by the monitored components. The potentials of the methodology are shown considering the case of a truck-mounted hydraulic crane, for which a simulation model was available.

关键词： perform prognostics electro-hydraulic machines independent metering controlled hydraulic crane

Proximity to corridors benefits bird communities in vegetated interrow vineyards in Mendoza, Argentina

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Avian Research 2024年第2期15卷 147-155页

作者： andrea Paula Goijman Agustín Zarco EEA La Consulta Instituto Nacional de Tecnología Agropecuaria(INTA)San CarlosMendozaArgentina Instituto Argentino de Investigacion en las Zonas Aridas(IADIZA)CONICET 5500MendozaArgentina

Management under ecological schemes and increasing habitat heterogeneity,are essential for enhancing biodiversity in *** provide several contributions to agriculture,for example pest control,recreation and enhancing human mental health,and have intrinsic *** are also ideal model organisms because they are easy to survey,and species respond differently to agricultural land use at different *** borders of crops are key for many species of birds,and distance to the border have been found to be an important factor in vineyard-dominated *** evaluate if there are differences in the bird assemblage,between the interior compared to borders within vineyards,using a hierarchical community occupancy *** hypoth-esized that occupancy of birds is greater in environments with greater heterogeneity,which in this study was considered to be contributed by the proximity to vegetated *** expected that vineyard borders close to corridors will have higher bird occupancy than the center of the *** research was conducted in three vineyards with biodiversity-friendly management practices,in Gualtallary,Mendoza,*** surveys were conducted over three breeding seasons from 2018 to *** and richness of the bird community was more closely associated with the borders adjacent to the corridors than with the interior of the vineyards,as we initially predicted,although the assemblage of birds did not differ *** than 75%of the registered species consume exclusively or partially ***-friendly management and ecological schemes,together with vegetated corridors provide multiple benefits for biodiversity *** ap-proaches not only minimize the use of agrochemicals but also prioritize soil cover with spontaneous vegetation,which supports a diverse community of insectivorous bird species,potentially contributing to pest control.

关键词： Avian Bayesian analysis Field scale agroecosystem Management Multi-species occupancy model Nature’s contributions to people

Laser-optimized Pt-Y alloy nanoparticles embedded in Pt-Y oxide matrix for high stability and ORR electrocatalytic activity

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Journal of Energy Chemistry 2024年第5期92卷 508-520页

作者： Riccardo Brandiele andrea Guadagnini Mattia Parnigotto Federico Pini Vito Coviello Denis Badocco Paolo Pastore Gian andrea Rizzi andrea Vittadini Daniel Forrer Vincenzo Amendola Christian Durante Department of Chemical Sciences University of PaduaVia Marzolo 135131 PadovaItaly Istituto di Chimica della Materia Condensata e di Tecnologie per l’Energia ICMATE-CNR via Marzolo 1 I-35131 PadovaItaly

The development of active yet stable catalysts for oxygen reduction reaction(ORR)is still a major issue for the extensive permeation of fuel cells into everyday *** nanostructured Pt catalysts are to date the best available systems in terms of activity,the same is not true for stability,particularly under operating *** this work,Pt_(Х)Y alloy nanoparticles are proposed as active and durable electrocatalysts for ***_(Х)Y nanoalloys are synthesized and further optimized by laser ablation in liquid followed by laser fragmentation in *** novel integrated laser-assisted methodology succeeded in producing Pt_(Х)Y nanoparticles with the ideal size(1000 A g^(-1).At the same time,the nanoalloys are embedded in a fine Pt oxide matrix,which allows a greater stability of the catalyst than the commercial Pt reference,as directly verified on a gas diffusion electrode.

关键词： Electrocatalysis GDE ORR Pt_(2)Y Pt_(3)Y LAL LFL Oxide support Pto Nanoalloys

Design methodology of a mini-missile considering flight performance and guidance precision

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Journal of Systems Engineering and Electronics 2024年第1期35卷 195-210页

作者： ZHANG Licong GONG Chunlin SU Hua andrea Da Ronch Shaanxi Aerospace Flight Vehicle Design Key Laboratory School of AstronauticsNorthwestern Polytechnical UniversityXi’an 710072China Faculty of Engineering and Physical Sciences University of SouthamptonSouthampton SO171BJUnited Kingdom

The design of mini-missiles(MMs)presents several novel *** stringent mission requirement to reach a target with a certain precision imposes a high guidance *** miniaturization of the size of MMs makes the design of the guidance,navigation,and control(GNC)have a larger-thanbefore impact on the main-body design(shape,motor,and layout design)and its design objective,i.e.,flight *** a trade-off between flight performance and guidance precision,all the relevant interactions have to be accounted for in the design of the main body and the GNC ***,a multi-objective and multidisciplinary design optimization(MDO)is *** pertinent to motor,aerodynamics,layout,trajectory,flight dynamics,control,and guidance are included in the proposed MDO *** optimization problem seeks to maximize the range and minimize the guidance *** problem is solved by using the nondominated sorting genetic algorithm *** optimum design that balances a longer range with a smaller guidance error is ***,lessons learned about the design of the MM and insights into the trade-off between flight performance and guidance precision are given by comparing the optimum design to a design provided by the traditional approach.

关键词： mini-missiles(MMs) guidance navigation and control(GNC)system multi-objective optimization multidisciplinary design optimization(MDO) flight performance guidance precision

Life cycle assessment as a prospective tool for sustainable agriculture and food planning at a local level

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Geography and Sustainability 2024年第2期5卷 251-264页

作者： andrea Lulovicova Stephane Bouissou UniversitéCôte d’Azur ESPACE Laboratory UMR730098bd Edouard Herriot06200 NiceFrance

Owing to the far-reaching environmental consequences of agriculture and food systems,such as their contribution to climate change,there is an urgent need to reduce their *** and national governments set sustainability targets and implement corresponding ***,critics of the globalized system claim that a territorial administrative scale is better suited to address sustainability ***,at the subnational level,local authorities rarely apply a systemic environmental assessment to enhance their action *** paper employs a territorial life cycle assessment methodology to improve local environmental agri-food *** objective is to identify significant direct and indirect environmental hotspots,their origins,and formulate effective mitigation *** methodology is applied to the administrative department of Finistere,a strategic agricultural region in North-Western *** environmental criteria including climate change,fossil resource scarcity,toxicity,and land use are *** findings reveal that the primary environmental hotspots of the studied local food system arise from indirect sources,such as livestock feed or diesel *** reduction and organic farming conversion emerge as the most environmentally efficient strategies,resulting in a 25%decrease in the climate change ***,the overall modeled impact reduction is insufficient following national objectives and remains limited for the land use *** results highlight the innovative application of life cycle assessment led at a local level,offering insights for the further advancement of systematic and prospective local agri-food ***,they provide guidance for local authorities to enhance the sustainability of planning strategies.

关键词： Environmental analysis Territorial life cycle assessment Prospective scenario Agri-food planning Local food system

Application of flame-formed carbon nanoparticle films for ethanol sensing Author links open overlay panel

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Particuology 2024年第8期91卷 202-210页

作者： Pegah Darvehi Luca Basta Mario Commodo Patrizia Minutolo andrea D'Anna Istituto di Scienze e Tecnologie per l’Energia e la MobilitàSostenibili Consiglio Nazionale delle RicercheP.le Tecchio 8080125NapoliItaly Dipartimento di Ingegneria Chimica dei Materiali e della Produzione IndustrialeUniversitàdegli Studi di Napoli Federico IIP.le Tecchio 8080125NapoliItaly

Carbon nanoparticles(CNPs)have received considerable attention due to their exceptional qualities and *** unique physical and chemical characteristics make them extremely intriguing as materials for numerous high-potential applications,such as electronics and gas *** study focused on producing carbon-based nanomaterial devices by deposition of flame-formed carbon nanoparticles on a suitable substrate and investigating their gas-sensing *** were produced in a fuel-rich laminar premixed ethylene/air flame and the collected CNP film was morphologically and electrically *** electrical conductivity of the film was investigated as a function of ethanol concentration and amount of deposited ***,CNP films exhibited high sensitivity to ambient ethanol gas concentrations,and rapid recovery times at room temperature,and showed a sensitivity increasing with the amount of deposited material and the surface *** findings demonstrate the high potential of combustion-generated CNPs as building materials for low-cost and portable ethanol sensors.

关键词： Flame synthesis Carbon nanoparticles Soot Nanostructured thin film Optical and electrical characterization Atomic force microscopy Sensors