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Discretized Miller approach to assess effects on boundary layer ingestion induced distortion

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Chinese Journal of Aeronautics 2017年第1期30卷 235-248页

作者： Esteban Valencia Víctor Hidalgo devaiah Nalianda Laskaridis Panagiotis Riti Singh departamento de ingeniería Mecánica Facultad de Ingeniería Mecánica Escuela Politécnica Nacional Ladron de Guevara E11-253 Quito 17-01-2759 Ecuador School of Engineering Cranfield University Bedford MK430AL United Kingdom

The performance of propulsion configurations with boundary layer ingestion（BLI） is affected to a large extent by the level of distortion in the inlet flow field. Through flow methods and parallel compressor have been used in the past to calculate the effects of this aerodynamic integration issue on the fan performance; however high-fidelity through flow methods are computationally expensive, which limits their use at preliminary design stage. On the other hand, parallel compressor has been developed to assess only circumferential distortion. This paper introduces a discretized semi-empirical performance method, which uses empirical correlations for blade and performance calculations. This tool discretizes the inlet region in radial and circumferential directions enabling the assessment of deterioration in fan performance caused by the combined effect of both distortion patterns. This paper initially studies the accuracy and suitability of the semiempirical discretized method by comparing its predictions with CFD and experimental data for a baseline case working under distorted and undistorted conditions. Then a test case is examined,which corresponds to the propulsor fan of a distributed propulsion system with BLI. The results obtained from the validation study show a good agreement with the experimental and CFD results under design point conditions.

关键词： BLI Correlations Distortion Embedded propulsors Empirical Mean-line analysis Turbomachinery

Kinetic behaviour of commercial catalysts for methane reforming in ethanol steam reforming process

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Journal of Energy Chemistry 2014年第5期23卷 639-644页

作者： Jorge Vicente Javier Erea Martin Olazar Pedro L.Benito Javier Bilbao Ana G.Gayubo departamento de ingeniería Química Universidad del País Vasco UPV/EHU Apartado 644 48080 Bilbao Spain departamento de ingeniería Minera y Metalúrgica y Ciencia de los Materiales Universidad del País Vasco UPV/EHUNieves Cano 12 01006 Vitoria-Gasteiz Spain

Ethanol steam reforming has been studied in a fluidized bed （in order to ensure bed isothermicity） on commercial catalysts for methane reforming. The results allow analyzing the effect of temperature （in 300-700℃ range）, and both metal and support nature on the reaction indices （ethanol conversion, yields and selectivities to H2 and byproducts （CO2, CO, CH4 and C2H4O））. Special attention has been paid to catalysts＇ stability by comparing the evolution of the reaction indices with time on stream at 500°C （minimum CO formation） and 700℃ （minimum deactivation by coke deposition）. Although they provide a slightly lower H2 yield, the results evidence a good behaviour of Ni based catalysts, indicating that they are an interesting alternative of more expensive Rh based ones.

关键词： ethanol steam reforming hydrogen commercial catalyst selectivity deactivation

Bioerosion on Late Pleistocene Marine Mollusks:A Paleoclimatological and Paleoecological Comparison of MIS 7 and MIS 5e with Modern Beaches(Río Negro,Argentina)

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Acta Geologica Sinica(English Edition) 2022年第4期96卷 1181-1198页

作者： Melisa P.CHARO Gisela D.CHARÓ Guillermo ACEÑOLAZA Jose L.CAVALLOTTO Instituto Superior de Correlación Geológica(INSUGEO/CONICET-UNT)Miguel Lillo 205 4000 TucumánArgentina Laboratorio de Fluidodinámica Departamento de Ingeniería MecánicaFacultad de IngenieríaUniversidad de Buenos AiresPaseo Colón 850C1063ACVCiudad Autónoma de Buenos AiresArgentina Servicio de Hidrografía Naval Av.Montes de Oca 2124C1270ABW Buenos AiresArgentina

The Late Pleistocene littoral ridges of southern South America,especially those of the north of Argentinean Patagonia,contain remains of mollusk shells with bioerosion traces.Eleven sites from marine isotope stages(2 from MIS 7,4 from MIS 5 e)and five sites from modern beaches from northern Río Negro Province,with 40 taxa(17 bivalves and 23 gastropods)were analyzed,in the area between west of Baliza San Matías and Las Grutas(41°S).Three ichnogenera were identified in deposits of MIS 7:Entobia,Gastrochaenolites(Domichnia)and Oichnus(Praedichnia)with one ichnospecies(G.torpedo).Six ichnogenera were identified in deposits of MIS 5 e:Entobia,Meandropolydora,Pinaceocladichnus,Iramena,Caulostrepsis and Oichnus with one ichnospecies(O.simplex).Seven ichnogenera were identified from modern beaches:Entobia,Meandropolydora,Iramena,Caulostrepsis,Pinaceocladichnus,Gastrochaenolites(Domichnia)and Oichnus(Praedicnia),with two ichnospecies(O.simplex and O.paraboloides).On this basis,it is inferred that Pleistocene benthic communities were constituted from cheilostome bryzoans and polychaete annelids,together with drilling bivalves,predatory gastropods and overall warm-water species of mollusks.Of these,Chama iudicai was found on Plicatula gibbosa from MIS 7 and MIS 5 e.The record of warm temperature species suggests a higher sea surface temperature(SST)than the present one and/or the influence of the warm southward Brazilian Current affecting the waters of Golfo San Matías.On the modern beaches surveyed,there is an increase in polychaete annelids,cheilostome bryzoans,temperate-cold species and drilling bivalves,as well as sandy substrate species,which together with an increase of Gastrochaenolites and Caulostrepsis,suggest a colder climate due to the greater influence of the Malvinas Current during the Holocene.

关键词： invertebrate paleontology ichnology Bivalvia Gastropoda Polyplacophora bioerosion paleoclimatology paleoecology Quaternary/Holocene Argentina

Modelling the impacts of cover crop management strategies on the water use,carbon exchange and yield of olive orchards

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Journal of Forestry Research 2023年第1期34卷 283-295页

作者： Alvaro López-Bernal Omar García-Tejera Luca Testi Francisco J.Villalobos departamento de Agronomía Universidad de CórdobaCampus de RabanalesEdifi cio C414071 CórdobaSpain departamento de ingeniería Agraria Y del Medio Natural Universidad de La LagunaCarretera General de Geneto 238200 San Cristóbal de La LagunaSpain Instituto de Agricultura Sostenible(IAS) Consejo Superior de Investigaciones Científi cas(CSIC)Av.Menéndez Pidal S/N14080 CórdobaSpain

Cover crops have long been proposed as an alternative soil management for minimizing erosion rates in olive stands while providing additional ecosystem services.However,the trade-off between these benefits and the competition for water with the trees makes the definition of optimal management practices a challenging task in semiarid climates.This work presents an improved version of OliveCan,a process-based simulation model of olive orchards that now can simulate the main impacts of cover crops on the water and carbon balances of olive orchards.Albeit simple in its formulation,the new model components were developed to deal with different cover crop management strategies.Examples are presented for simulation runs of a traditional olive orchard in the conditions of southern Spain,evaluating the effects of different widths for the strip occupied by the cover crop(Fcc)and two contrasting mowing dates.Results revealed that high Fccresulted in lower olive yields,but only when mowing was applied at the end of spring.In this regard,late mowing and high Fccwas associated with lower soil water content from spring to summer,coinciding with olive flowering and the earlier stages of fruit growth.Fccwas also negatively correlated with surface runoff irrespective of the mowing date.On the other hand,net ecosystem productivity(NEP)was substantially affected by both Fccand mowing date.Further simulations under future climate scenarios comparing the same management alternatives are also presented,showing substantial yield reductions by the end of the century and minor or negligible changes in NEP and seasonal runoff.

关键词： Carbon exchange Cover crops Crop modelling Evapotranspiration Olea europaea L

Performance evaluation of lateral canopy shakers with catch frame for continuous harvesting of oranges for juice industry

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International Journal of Agricultural and Biological Engineering 2020年第3期13卷 88-93,F0002页

作者： Rafael R.Sola-Guirado Sergio Castro-Garcia Gregorio L.Blanco-Roldán Jesús A.Gil-Ribes Emilio J.González-Sánchez Universidad de Córdoba Departamento de Ingeniería RuralE.T.S.I.Agronómica y de MontesCampus de RabanalesCtra.Nacional IV Km 396CordobaSpain

Citrus is mainly oriented to fresh consumption,and harvesting is usually performed manually.However,the high cost of harvesting and the low availability of labour can compromise the profitability of the crop when it is destined to juice industry.The development of citrus mechanical harvesting for industrial processing is conditioned to reach a high fruit removal efficiency,with a reduced damage to both fruit and trees.The current machines available are very large,requiring extensive plantations with long rows of trees to be efficient.In this study,two lateral canopy shakers equipped with a catch frame were evaluated to harvest independently both sides of the hedge on intensive citrus plantations with the main objective of determining their performance and feasibility.The lateral canopy shakers tested were three tractor-drawn machines,one commercial machine and two prototypes.The tested machines reached a mean value of 78%of fruit removal.Besides,the prototypes,equipped with a catch frame,were able to recover a mean value of 70%of yield.Although the results were promising,for achieving an efficient result,the application of this harvesting technology still requires a process of improvement,and the adaptation of both the machine and the plantation.The machines should reduce the amount of post-harvest ground fruit(5.9%-10.4%).Tree damages generated by the contact of the catch frame with the trunk and the metal rods with main branches were the most relevant.Therefore,it is still necessary to increase the ground speed of the machinery and improving the design of the rods,regulating the rod penetrating deep in the canopy to improve the fruit recovery and limit the damage caused to the trees.

关键词： harvester mechanical harvesting fruit removal tree damage Citrus sinensis L.Osbeck

Quasi-in vivo corrosion behavior of AZ31B Mg alloy with hybrid MWCNTs-PEO/PCL based coatings

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Journal of Magnesium and Alloys 2022年第11期10卷 3217-3233页

作者： Morteza Daavari Masoud Atapour Marta Mohedano Hugo Mora Sánchez Juan Rodríguez-Hernández Endzhe Matykina Raul Arrabal Aboozar Taherizadeh department of Materials Engineering Isfahan University of Technology84156-83111 IsfahanIran departamento de ingeniería Química y de Materiales Facultad de Ciencias QuímicasUniversidad Complutense28040 MadridSpain Institute of Polymer Science and Technology(CSIC) Polymer Functionalization GroupMadrid 28006Spain

This study investigated the effects of multi-walled carbon nanotubes(MWCNTs) and polycaprolactone(PCL) on the quasi-in vivo corrosion behavior of AZ31B Mg alloy treated by plasma electrolytic oxidation(PEO). Thin(~2 μm, PCTPCL4) and thick(~60 μm, PCTPCL6) PCL layers were applied only onto the MWCNTs-PEO coating(PCT) as it showed better corrosion performance. Findings reveal that incorporation of MWCNTs induced several structural and functional modifications in the PEO coating, such as increased roughness, a thicker inner barrier layer, and reduced hydrophilicity.Quasi-in vivo corrosion testing was carried out under controlled temperature, p H, and fluid flow in simulated body fluid(SBF) by electrochemical impedance spectroscopy(EIS) and hydrogen evolution experiments. EIS results revealed that, after 48 h immersion, a diffusion process controlled hydration of the ceramic coatings. Comparison of the collected hydrogen after 15 days of immersion in the quasi-in vivo environment revealed that the PEO and PCT ceramic coatings decreased hydrogen generation by up to 74% and 91%, respectively, compared to non-coated alloy.PCTPCL6 coating exhibited the lowest amount of collected hydrogen(0.2 m L/cm^(2)). The thick PCL layer delayed the onset of substrate corrosion for at least 120 h, reducing the corrosion rate by 85% compared with the PCT.

关键词： AZ31B Mg alloy Plasma electrolyte oxidation(PEO) Multi-walled carbon nanotubes(MWCNTs) Quasi-in vivo condition Polycaprolactone(PCL)

Novel strategies to tailor the photocatalytic activity of metal–organic frameworks for hydrogen generation: a mini-review

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Frontiers in Energy 2022年第5期16卷 734-746页

作者： Luis A.ALFONSO-HERRERA Leticia M.TORRES-MARTINEZ J.Manuel MORA-HERNANdeZ Universidad Autónoma de Nuevo León UANLFacultad de Ingeniería CivilDepartamento de Ecomateriales y EnergíaAv.Universidad S/N Ciudad UniversitariaSan Nicolás de los GarzaNuevo León 66455México Centro de Investigación en Materiales Avanzados S.C.(CIMAV)Miguel de Cervantes No.120.Complejo Ind.ChihuahuaChihuahuaChih 31136México CONACYT-Universidad Autónoma de Nuevo León UANLFacultad de Ingeniería CivilDepartamento de Ecomateriales y EnergíaAv.Universidad S/N Ciudad UniversitariaSan Nicolás de los GarzaNuevo León 66455México

This review provides a recompilation of the most important and recent strategies employed to increase the efficiency of metal-organic framework(MOF)-based systems toward the photocatalytic hydrogen evolution(PHE)reaction through specific strategies:tailoring the photocatalytic activity of bare MOFs and guest@MOF composites,formation of heterojunctions based on MOFs and various photocatalysts,and inorganic photocatalysts derived from MOFs.According to the data reported in this mini-review,the most effective strategy to improve the PHE of MOFs relies on modifying the linkers with new secondary building units(SBUs).Although several reviews have investigated the photocatalytic activity of MOFs from a general point of view,many of these studies relate this activity to the physicochemical and catalytic properties of MOFs.However,they did not consider the interactions between the components of the photocatalytic material.This study highlights the effects of strength of the supramolecular interactions on the photocatalytic performance of bare and MOF-based materials during PHE.A thorough review and comparison of the results established that metal-nanoparticle@MOF composites have weak van der Waals forces between components,whereas heterostructures only interact with MOFs at the surface of bare materials.Regarding material derivatives from MOFs,we found that pyrolysis destroyed some beneficial properties of MOFs for PHE.Thus,we conclude that adding SBUs to organic linkers is the most efficient strategy to perform the PHE because the SBUs added to the MOFs promote synergy between the two materials through strong coordination bonds.

关键词： metal-organic frameworks(MOFs) photocatalytic hydrogen evolution MOF heterojunctions materials derived from MOFs bandgap recombination

MMALE—A Methodology for Malware Analysis in Linux Environments

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Computers, Materials & Continua 2021年第5期67卷 1447-1469页

作者： JoséJavier de Vicente Mohino Javier Bermejo Higuera Juan Ramón Bermejo Higuera Juan Antonio Sicilia Montalvo Manuel Sánchez Rubio JoséJavier Martínez Herraiz Escuela Superior de ingeniería y Tecnología Universidad Internacional de La RiojaLogroño26006La RiojaSpain departamento de Ciencias de la Computación de la Escuela Politécnica Superior Universidad de Alcaláde HenaresAlcaláde HenaresMadridSpain

In a computer environment,an operating system is prone to malware,and even the Linux operating system is not an exception.In recent years,malware has evolved,and attackers have become more qualified compared to a few years ago.Furthermore,Linux-based systems have become more attractive to cybercriminals because of the increasing use of the Linux operating system in web servers and Internet of Things(IoT)devices.Windows is the most employed OS,so most of the research efforts have been focused on its malware protection rather than on other operating systems.As a result,hundreds of research articles,documents,and methodologies dedicated to malware analysis have been reported.However,there has not been much literature concerning Linux security and protection from malware.To address all these new challenges,it is necessary to develop a methodology that can standardize the required steps to perform the malware analysis in depth.A systematic analysis process makes the difference between good and ordinary malware analyses.Additionally,a deep malware comprehension can yield a faster and much more efficient malware eradication.In order to address all mentioned challenges,this article proposed a methodology for malware analysis in the Linux operating system,which is a traditionally overlooked field compared to the other operating systems.The proposed methodology is tested by a specific Linux malware,and the obtained test results have high effectiveness in malware detection.

关键词： Malware analysis methodology analysis Linux malware IoT malware

Temporal decay of the catalytic oxidation of methane over palladium supported on silica

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Science China Chemistry 2013年第11期56卷 1601-1607页

作者： CORTS Joaquín VALENCIA Eliana PINEDA Marcelo ARAYA Paulo departamento de ingeniería Química y Biotecnología Universidad de Chile departamento de Ciencia de Materiales Universidad de Chile

The temporal decay of the oxidation of methane(CH4-O2reaction)over palladium supported on silica is determined experimentally at different temperatures,comparing the results with those of various classical models which show the behavior of the adsorbed phase as the cause of the phenomenon.This effect is visualized through Monte Carlo simulations of the CH4-O2reaction on a mixed lattice whose partial poisoning,due to the configuration of the OH groups on the surface of the adsorbate,is translated into a gradual decay of the reaction’s activity.

关键词：二氧化硅变负载催化氧化时间甲烷钯实验确定经典模型