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A methodological framework for improving air quality monitoring network *** to environment management

Journal of Environmental Sciences 2021年第4期33卷 138-147页

作者： David Galán-Madruga Department of Atmospheric Pollution National Center for Environment HealthHealth Institute Carlos IIICtra.Majadahonda a Pozuelo km 2228220 MadridSpain

This work aims to provide a methodology framework which allows to improve the performance and efficiency of an air quality monitoring network(AQMn).It requires to be constituted by a minimum and reliable number of measurement ***,the AQMn efficiency should be assessed over time,as a consequence of the possible emergence of new emission sources of air pollutants,which could lead to variations on their spatial distribution within the target ***_(10)particles data monitored by the Community of Madrid's(Spain)AQMn between 2008 and 2017 were used to develop a methodology to optimize the AQMn *** annual spatial distribution of average PM_(10)levels over the studied period monitored by all current stations vs those more representative was provided by a geographic information system(GIS),and the percentage of similarity between both postulates was quantified using simple linear regression(>95%).As one innovative tool of this study,the practical application of the proposed methodology was validated using PM_(10)particles data measured by AQMn during 2007 and 2018,reaching a similitude degree higher than 95%.The influence of temporal variation on the proposed methodological framework was around 20%.The proposed methodology sets criteria for identifying non-redundant stations within AQMn,it is also able to appropriately assess the representativeness of fixed monitoring sites within an AQMn and it complements the guidelines set by European legislation on air pollutants monitoring at fixed stations,which could help to tackle efforts to improve the air quality management.

关键词： Air quality Ambient air monitoring network PM_(10)particles Redundant stations Optimization Environment management

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InVESTIGATIOn OF DOMInAnT FREQUEnCIES In TRAnSITIOn REYnOLDS nUMBER RAnGE OF FLOW AROUnD A CIRCULAR CYLInDER PART I:EXPERIMEnTAL STUDY OF THE RELATIOn BETWEEn VORTEX SHEDDInG AnD TRAnSITIOn FREQUEnCIES

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Chinese Journal of Mechanical Engineering 2006年第3期19卷 159-167页

作者： AHMED n A School of Mechanical and Manufacturing Engineering University of new South Wales Sydney 2052 Australia

A comprehensive hot wire investigation of the flow around a circular cylinder is carried out in an 18＂ × 18＂ wind tunnel to look into the dominant frequencies at the stagnation, separation and separated shear layers in the transition Reynolds number range. The majority of the experiments are carried out at Reynolds number of 4.5×104, with additional transition frequency tests at Reynolds numbers of 2.9×104, 3.3×104 and 9.7×104 respectively. The results are analysed in terms of power spectral density. While the frequency associated with stagnation is found to be essentially due to vortex shedding, frequency doubling of vortex shedding is also evident in the separated shear layers. Two peaks associated with transition frequencies are detected and their possible implications are presented.

关键词： Vortex shedding Transition Separated flow Power spectral density

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Structure and Properties of Functionalized Polyfluorenone Containing Hetero Aromatic Side Chains

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Chinese Journal of Polymer Science 2014年第5期32卷 667-674页

作者： R.Venkatesan n.Somanathan n.Rajeswari Department of Printing Technology College of Engineering Guindy Anna University Polymer lab Central Leather Research institute

The optical properties of substituted fluorenones with diverse structures have been analyzed using molecular orbital calculations in order to understand the structure-property relations. Based on theoretical predictions, synthesis of some model compounds has been attempted. The experimentally obtained optical properties are in close agreement with the theoretically obtained results.

关键词： Conjugated polymer UV-Visible spectroscopy Band gap Structure and properties Molecular orbital calculations.

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Positron scattering and ionization of neon atoms—theoretical investigations

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Chinese Physics B 2010年第10期19卷 245-250页

作者： Harshit n. Kothari K. n. Joshipura Department of Physics Sardar Patel University Vallabh Vidyanagar-388120 India

Although positron scattering with inert gas atoms has been studied in theory as well as in experiment, there are discrepancies. The present work reports all the major total cross sections of e＋-neon scattering at incident energies above ionization threshold, originating from a complex potential formalism. Elastic and cumulative inelastic scatterings are treated in the complex spherical e＋-atom potential. Our total inelastic cross section includes positronium formation together with ionization and excitation channels in ne. Because of the Ps formation channel it is difficult to separate out ionization cross sections from the total inelastic cross sections. An approximate method similar to electron-atom scattering has been applied to bifurcate ionization and cumulative excitation cross sections at energies from threshold to 2000 eV. Comparisons of present results with available data are made. An important outcome of this work is the relative contribution of different scattering processes, which we have shown by a bar-chart at the ionization peak.

关键词： ionization cross sections positron scattering complex potential total cross sections

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Modal Decomposition for the Analysis of the Rotor-stator Interactions in Multi-stage Compressors

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Journal of Thermal Science 2012年第3期21卷 276-285页

作者： n.Courtiade X.Ottavy n.Gourdain Laboratoire de Mécanique des Fluides et d'Acoustique Ecole Centrale de Lyon CERFACS CFD Team

A modal analysis method of the rotor-stator interactions in multistage compressors has been developed by LMFA. This method, based on a double modal decomposition of the flow over space and time, has been applied to nu- merical and experimental results of the high-speed 3Y2-stage compressor CREATE based at LMFA, Lyon-France. It reveals the presence of a very strong rotor-stator interaction which completely drives the flow at casing behind all the rotors. This modal analysis method applied to an unsteady RAnS simulation permits to calculate the en- ergy of the rotor-stator interactions and to plot energetic meridian maps to explain experimental results and to analyze the interaction in the whole machine.

关键词： rotor-stator interactions modal analysis multistage compressors numerical and experimental results

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ERROR ESTIMATES FOR THE TIME DISCRETIZATIOn FOR nOnLInEAR MAXWELL'S EQUATIOnS

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Journal of Computational Mathematics 2008年第5期26卷 677-688页

作者： Mavián Slodika Ján Bua Jr. Department of Mathematical Analysis Ghent University

This paper is devoted to the study of a nonlinear evolution eddy current model of the type δtB（H）＋ △↓× （ △↓ × H） =0 subject to homogeneous Dirichlet boundary conditions H × v = 0 and a given initial datum. Here, the magnetic properties of a soft ferromagnet are linked by a nonlinear material law described by B（H）. We apply the backward Euler method for the time discretization and we derive the error estimates in suitable function spaces. The results depend on the nonlinearity of B（H）.

关键词： Electromagnetic field nonlinear eddy current problem Time discretization,Error estimate.

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Compression properties of cost-efficient porous expanded clay reinforced AA7075 syntactic foams fabricated by industrial-oriented die casting technology

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China Foundry 2024年第1期21卷 60-70页

作者： İsmail Cem Akgün Çağın Bolat Ali Gökşenli Faculty of Mechanical Engineering Istanbul Technical University34437İstanbulTurkey Faculty of Engineering Samsun University55420SamsunTurkey

In today’s manufacturing industries,hard competition between rival firms makes it compulsory for researchers to design lighter and cheaper machine components due to the megatrends of cost-effectiveness and *** this point,aluminum syntactic foams(ASFs)are new-generation engineering composites and come into the upfront as a *** to their features like low density,sufficient elongation,and perfect energy absorption ability,these advanced foams have been considerably seductive for many industrial sectors *** this study,an industrial-oriented automatic die casting technology was used for the first time to manufacture the combination of AA7075/porous expanded clay(PEC).Micro evaluations(optical and FESEM)reveal that there is a homogenous particle distribution in the foam samples,and inspections are compatible with the other ASF ***,T6 aging heat treatment was operated on one half of the produced foams to explore the probable impact of aging on the compressive *** results show that PEC particles can be an alternative to expensive hollow spheres used in the previous ***,a favorable relationship is ascertained between the aging treatment and mechanical properties such as compression strength and plateau strength.

关键词： die casting porous materials metal matrix sytanctic foams expanded clay compressive deformation

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Travel time prediction with viscoelastic traffic model

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Applied Mathematics and Mechanics(English Edition) 2018年第12期39卷 1769-1788页

作者： Yongliang ZHAnG M.n.SMIRnOVA A.I.BOGDAnOVA Zuojin ZHU n.n.SMIRnOV Faculty of Engineering Science University of Science and Technology of China Faculty of Mechanics and Mathematics Moscow M.V.Lomonosov State University Scientific Research Institute for System Analysis Russian Academy of Sciences

Travel time through a ring road with a total length of 80 km has been predicted by a viscoelastic traffic model(VEM), which is developed in analogous to the non-newtonian fluid flow. The VEM expresses a traffic pressure for the unfree flow case by space headway, ensuring that the pressure can be determined by the assumption that the relevant second critical sound speed is exactly equal to the disturbance propagation speed determined by the free flow speed and the braking distance measured by the average vehicular length. The VEM assumes that the sound speed for the free flow case depends on the traffic density in some specific aspects, which ensures that it is exactly identical to the free flow speed on an empty road. To make a comparison, the open navier-Stokes type model developed by Zhang(ZHAnG, H. M. Driver memory, traffic viscosity and a viscous vehicular traffic flow model. Transp. Res. Part B, 37, 27–41(2003)) is adopted to predict the travel time through the ring road for providing the counterpart *** the traffic free flow speed is 80 km/h, the braking distance is supposed to be 45 m,with the jam density uniquely determined by the average length of vehicles l ≈ 5.8 m. To avoid possible singular points in travel time prediction, a distinguishing period for time averaging is pre-assigned to be 7.5 minutes. It is found that the travel time increases monotonically with the initial traffic density on the ring road. Without ramp effects, for the ring road with the initial density less than the second critical density, the travel time can be simply predicted by using the equilibrium speed. However, this simpler approach is unavailable for scenarios over the second critical.

关键词： travel time viscoelastic modeling distinguishing period for time averaging spatial-temporal pattern traffic jam

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APPROXIMATIOn OF FUnCTIOnS BY(n,p)OPERATOR

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Analysis in Theory and Applications 1994年第2期10卷 67-73页

作者： S.n.Dubey A.Kumar Sanjay Gandhi Sarvodaya Science college India R. D. University India Principal Sanjay Gandhi Sarvodaya Science College Ranital Jabalpur 482002 (M. P.) India R. D. University Jabalpur

The present paper deals with finding of constant occurring in the order of approximation of the function of Lipα(O <α<1) class by using (n, p) operator. Obviously the factor 1/ (1 - α) becomes large when α is clos... 详细信息

The present paper deals with finding of constant occurring in the order of approximation of the function of Lipα(O ng (n, p) operator. Obviously the factor 1/ (1 - α) becomes large when α is close to 1. We have shown the role of this factor in the constant of approximation.

关键词： APPROXIMATIOn OF FUnCTIOnS BY n,p)OPERATOR 占一 Abel

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Rheological and tribological approaches as a tool for the development of sustainable lubricating greases based on nano-montmorillonite and castor oil

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Friction 2021年第2期9卷 415-428页

作者： Jose Enrique MARTÍn-ALFOnSO María Jose MARTÍn-ALFOnSO Concepción VALEnCIA María Teresa CUBERES Department of Chemical Engineering and Materials Science Campus de“El Carmen”University of HuelvaChemical Product and Process Technology Research Center(Pro2TecS)Huelva 21071Spain Department of Applied Mechanics and Project Engineering University of Castilla-La ManchaAlmadén 13400Spain

This study investigates the development of novel montmorillonite/castor oil blends to formulate sustainable lubricating greases to promote the replacement of petrochemicals industry-derived materials by substances obtained from renewable ***,the effect of the thickener concentration on the rheological,chemical,thermal,tribological properties,and atomic force microscopy(AFM)microstructure of these systems were *** results showed that the C20A nanoclay content could be used to modulate the viscosity values,the linear viscoelastic functions,and tribological properties of these montmorillonite *** general,these gel-like dispersions exhibited remarkable lubricant properties;the samples showed values of the friction coefficient and wear scars similar or lower than those obtained with model bentonite grease.

关键词： lubricating greases nanoclay vegetable oil rheology tribology

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