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Simulation of temperature distribution and discharge crater of SiC_(p)/Al composites in a single-pulsed arc discharge

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Chinese Journal of Aeronautics 2021年第9期34卷 37-46页

作者： Jipeng CHEN Lin GU Wansheng ZHAO mario GUAGLIANO School of Mechanical and Electronic Engineering Nanjing Forestry UniversityNanjing 210037China State Key Laboratory of Mechanical System and Vibration School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240China Department of Mechanical Engineering Politecnico Di MilanoPiazza Leonardo da Vinci32Italy

SiC_(p)/Al composites are difficult-to-cut *** recent years,electrical arc discharge machining has been developed to improve the machinability of these ***,there is a big challenge to build a satisfactory heat transfer model of SiC_(p)/Al composites in the arc *** is not only because of the material property difference between the reinforcement and matrix material but also because of the micro-dimension Si C *** paper established a new heat conduction simulation model considering the Si C particle-Al matrix interface and the phase change effects in a single-pulsed arc discharge of SiC_(p)/Al composites.A novel Si C particle-Al matrix cell geometric model was designed ***,the temperature distribution at a different depth from the workpiece surface was analyzed,the influence of sic volume fraction on temperature field was studied,and the contribution of the interface thermal resistance and latent heat were *** demonstrate the validity of the new numerical model,comparisons and verifications were ***,the method of improving the model was proposed and the machining mechanism of arc discharge of SiC_(p)/Al matrix materials was *** was found that high temperature is prone to concentrate on the surface layers of the workpiece especially when the Si C fraction is high,also,the temperature fluctuates respectively at the evaporation point of aluminum and Si C,and the Si C-Al resistance has less influence on temperature distribution compared to latent heat,*** model build in this work improves the simulation accuracy observably compared to the previous model,and the simulation work will help to acquire a detailed mechanism of material removal of SiC_(p)/Al composites in the arc discharge machining.

关键词： Arc discharge Discharge crater SiC_(p)/Al composites Single-pulsed Temperature distribution

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Niche segregation, competition, and urbanization

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Current Zoology 2018年第2期64卷 145-152页

作者： Anders PAPE MФLLER mario DiAz Ecologie Systematique Evolution CNRS Universite Paris-Sud AgroParisTech Universite Pari-Saclay OrsayCedex F-91400 France Department of Biogeography and Global Change (BGC-MNCN-CSIC) NationalMuseum of Natural Sciences CSIC c/Serrano 155bis Madrid E-28006 Spain

Urbanization of species is an ongoing process where successful urban colonizers usually obtain large fitness benefits. Mechanisms proposed to explain associations between urbanization and lifehistory traits are based on behavioral flexibility in food and habitat use and reduced fear responses. We test the novel hypothesis that interspecific competition for proximity to humans is driving ur- banization. We recorded the distance during the breeding season to human habitation for 50 pairs of closely related bird species, where one was closely associated with humans while the other species was not. The degree of urbanization was larger as was range size and abundance in the species more closely associated to humans. Flight initiation distance was shorter, and species closely associated with humans were more abundant in ancestral rural habitats. Likewise, species more closely associated with humans reproduced earlier and during longer periods. These results are consistent with the hypothesis that urbanization is promoted by interspecific competition. Resulting isolation by urban habitat may further facilitate contemporary adaptation to urban environments.

关键词： birds distance to human habitation isolation by habitat isolation by time mechanisms.

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Changing Energy Consumption Behaviour: Individuals' Responsibility and Government Role

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Journal of Electronic Science and Technology 2015年第4期13卷 343-348页

作者： Mohamad Aldabas mario Gstrein Stephanie Teufel International Institute of Management in Technology (iimt) University of Fribourg

Renewable energy is clearly a very important topic nowadays. The risk and the damage that could be caused by conventional energy resources cannot be hidden. There is an enormous need that people start formulating a better attitude towards renewable energy and change their consumption behaviour. Otherwise, the future of environment and the coming generations is defiantly not going to be promising. This paper will discuss the importance of sustainable energy and how the energy related behaviour is created. It will present a framework to influence the current behaviour and push it to be more green oriented. It is also important to know till what limit are governments responsible in this change, and what are the tools that they have to push towards green direction.

关键词： Breaking bad habits green andrenewable energy energy consumption behavior.

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The Impact of Delay in Software-Defined Integrated Terrestrial-Satellite Networks

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China Communications 2018年第8期15卷 11-21页

作者： Luca Boero mario Marchese Fabio Patrone Department of Electrical Electronics and Telecommunication Engineering and Naval Architecture (DITEN) University of Genoa

Satellite communication networks have been evolving from standalone networks with ad-hoc infrastructures to possibly interconnected portions of a wider Future Internet architecture. Experts belonging to the fifth-generation(5 G) standardization committees are considering satellites as a technology to integrate in the 5 G environment. Software Defined Networking(SDN) is one of the paradigms of the next generation of mobile and fixed communications. It can be employed to perform different control functionalities, such as routing, because it allows traffic flow identification based on different parameters and traffic flow management in a centralized way. A centralized set of controllers makes the decisions and sends the corresponding forwarding rules for each traffic flow to the involved intermediate nodes that practically forward data up to the destination. The time to perform this process in integrated terrestrial-satellite networks could be not negligible due to satellite link delays. The aim of this paper is to introduce an SDN-based terrestrial satellite network architecture and to estimate the mean time to deliver the data of a new traffic flow from the source to the destination including the time required to transfer SDN control actions. The practical effect is to identify the maximum performance than can be expected.

关键词： Integrated terrestrial-satellite net-works software defined networking software defined satellite networks delay estimation

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Impact of Business Practices on Individual Energy Consumption

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Journal of Electronic Science and Technology 2015年第4期13卷 349-354页

作者： Stephane Egger mario Gstrein Stephanie Teufel International Institute of Management in Technology University of Fribourg

Changing behaviours and attitudes towards more sustainable individual energy consum- ption is a difficult topic to address. After identifying the most recurrent factors influencing bad energy consum- ption-society＇s environmental short- sightedness, a lack of individual responsibility and a tendency to put responsibility upon firms, institutions, and governments, the authors evaluated the effect business practices can have on individual behaviour. By qualifying as highly credible sources of information, positioning themselves as examples to follow and providing its employees with the necessary smart, innovative technology, business communities can have a major impact on changing individual behaviours towards more sustainable energy consumption.

关键词： Business practices individualbehaviour sustainable energy consumption.

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SHADOWING,EXPANSIVENESS AND SPECIFICATION FOR C^1-CONSERVATIVE SYSTEMS

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Acta Mathematica Scientia 2015年第3期35卷 583-600页

作者： mario BESSA Manseob LEE 文晓 Universidade da Beira Interior Rua Marques d'Avila e Bolama Department of Mathematics Mokwon University The School of Mathematics and Systems Science Beihang University

We prove that a Cl-generic volume-preserving dynamical system （diffeomor- phism or flow） has the shadowing property or is expansive or has the weak specification property if and only if it is Anosov. Finally, as in [10, 27], we prove that the Cl-robustness, within the volume-preserving context, of the expansiveness property and the weak specifica- tion property, imply that the dynamical system （diffeomorphism or flow） is Anosov.

关键词： Shadowing expansiveness specification generic Anosov volume-preserving star systems

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On Several New Hilbert-type Inequalities Involving Means Operators

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Acta Mathematica Sinica,English Series 2013年第8期29卷 1493-1514页

作者： Vandanjav ADIYASUREN Tserendorj BATBOLD mario KRNI Department of Mathematical Analysis National University of Mongolia Institute of Mathematics National University of Mongolia Faculty of Electrical Engineering and Computing University of Zagreb

In this paper, we establish several new Hilbert-type inequalities with a homogeneous kernel, involving arithmetic, geometric, and harmonic mean operators in both integral and discrete case. Such inequalities are derived by virtue of some recent results regarding general Hilbert-type inequalities and some well-known classical inequalities. We also prove that the constant factors appearing in established inequalities are the best possible. As an application, we consider some particular settings and compare our results with previously known from the literature.

关键词： Hilbert inequality Hilbert-type inequality Hardy inequality Carleman inequality Knopp inequality

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Analysis of the Stakeholder Engagement in the Deployment of Renewables and Smart Grid Technologies

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Journal of Electronic Science and Technology 2015年第3期13卷 221-228页

作者： Valeriia Vereshchagina mario Gstrein Bernd Teufel International Institute of Management in Technology University of Fribourg the International Institute of Management in Technology University of Fribourg

The implementation of higher shares of renewables in a global energy mix has to be accompanied by simultaneous deployment of enabling smart grid technologies （SGTs）. This combination will inevitably lead to a revolutionary change in a conventional energy system, particularly, the shifting role of consumers to prosnmers. But resistance may arise from such a dramatic shift, since it is associated with high uncertainty in conjunction with increasing responsibilities of all stakeholders, the urgent need of effective control, and the development of a process. To ensure the positive influence, coherent actions of all players, and appropriate treatment of the spots of resistance, the analysis of the interplay between key stakeholders has been done. The paper introduces the framework for stakeholders＇ analysis, applies it on the European Union （EU） example, and provides recommendations to reduce the resistance of SGTs deployment.

关键词： Communication strategy crowd energy renewable energy smart grid technologies stakeholder analysis.

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Do Rules and Patterns Affect Design Maintainability?

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Journal of Computer Science & Technology 2009年第2期24卷 262-272页

作者： Javier Garzás Félix García mario Piattini Kybele Consulting Madrid Spain Department of Information Technologies and Systems-Escuela Superior de Informáica University of Castilla-La Mancha Alarcos Research Group-Institute of Information Technologies and Systems Department of Information Technologies and Systems-Escuela Superior de Informáica University of Castilla-La Mancha

At the present time, best rules and patterns have reached a zenith in popularity and diffusion, thanks to the software community＇s efforts to discover, classify and spread knowledge concerning all types of rules and patterns. Rules and patterns are useful elements, but many features remain to be studied if we wish to apply them in a rational manner. The improvement in quality that rules and patterns can inject into design is a key issue to be analyzed, so a complete body of empirical knowledge dealing with this is therefore necessary. This paper tackles the question of whether design rules and patterns can help to improve the extent to which designs are easy to understand and modify. An empirical study, composed of one experiment and a replica, was conducted with the aim of validating our conjecture. The results suggest that the use of rules and patterns affect the understandability and modifiability of the design, as the diagrams with rules and patterns are more difficult to understand than non-rule/pattern versions and more effort is required to carry out modifications to designs with rules and patterns.

关键词： design patterns and rules maintainability software quality object-oriented design

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Long-term experimental study on gravitational sedimentation of water aluminum oxide nanofluid at different volumetric concentrations

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International Journal of Sediment Research 2023年第3期38卷 303-315页

作者： mario Misale Johan Augusto Bocanegra Annalisa Marchitto DIME-Department of Mechanics Energetics Management and Transportation Thermal Engineering and Environmental Conditioning Division University of Genoa

The stability of nanofluids is critical in engineering applications. The sedimentation of the nanoparticles in the base fluid limits the stability of the nanofluid. By measuring the absorbance of a visible laser through water aluminum oxide nanofluids it is possible to observe the evolution of the sedimentation process. A simple experimental setup consisting of a thin closed test cavity（0.8 mm or 1.5 mm thickness）filled with nanofluid and a set of laser diodes-photodiodes pairs was used in the experiments to determine the absorbance and the local volumetric concentration. The evolution of the local volumetric concentration of the nanofluid was measured at 13 height positions along the test cavity. Five initial volumetric concentrations of aluminum oxide（Al2O3; 0.5%, 1.0%, 1.5%, 2.0%, 3.0% and 4.0%） were considered. Data and digital photos were acquired for a total time lapse of 260 days. The results were independent of the container thickness. The same general trend was consistent for all the initial volumetric concentrations, i.e., the sedimentation rate decreases in time. The time evolution of the volumetric concentration was compared with results from a modified Mason-Weaver model. The comparison was possible by setting a variable sedimentation velocity in the model, suggesting that the sedimentation is affected by the dynamics of nanoparticle clusters with diverse sizes produced by agglomeration.

关键词： Pure nanofluid Aluminum oxide Nanoscale alumina particles Colloid sedimentation Nanoparticle settling Mason-Weaver model

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