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spatiotemporal assessment of particulate matter(PM_(10) and PM_(2.5)) and ozone in a Caribbean urban coastal city

Geoscience Frontiers 2022年第1期13卷 437-445页

作者： Ana l.Duarte Ismael l.schneider Paulo Artaxo Marcos l.s.Oliveira Department of Civil and Environmental Universidad de la CostaCalle 58#55-66080002 BarranquillaAtlánticoColombia Instituto de Física Universidade de São PauloSão PauloBrazil Universidad de lima Avenida Javier Prado Este 4600Santiago de Surco 1503Peru

Air pollution has become a critical issue in urban areas,so a broad understanding of its spatiotemporal characteristics is important to develop public *** study analyzes the spatiotemporal variation of atmospheric particulate matter(PM_(10) and PM_(2.5))and ozone(O_(3))in Barranquilla,Colombia from March 2018 to June 2019 in three monitoring *** average concentrations observed for the Móvil,Policía,and Tres Avemarías stations,respectively,for PM_(10):46.4,51.4,and 39.7μg/m^(3);for PM_(2.5):16.1,18.1,and 15.1μg/m^(3) and for O_(3):35.0,26.6,and 33.6μg/m^(3).The results indicated spatial and temporal variations between the stations and the pollutants *** highest PM concentrations were observed in the southern part of the city,while for ozone,higher concentrations were observed in the *** variations are mainly associated with the influence of local sources in the environment of each site evaluated as well as the meteorological conditions and transport patterns of the study *** study also verified the existence of differences in the concentrations of the studied pollutants between the dry and rainy seasons and the contribution of local sources as biomass burnings from the Isla salamanca Natural Park and long-range transport of dust particles from the sahara *** study provides a scientific baseline for understanding air quality in the city,which enables policy makers to adopt efficient measures that jointly prevent and control pollution.

关键词： Particulate matter Ozone Colombian Caribbean Coastal urban area

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Bringing Norwegian mine into world of bits and bytes——possibilities and pitfalls

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中国有色金属学会会刊：英文版 2005年第S1期15卷 262-265页

作者： s. l. Ellefmo E. ludvigsen Department of Geology and Mineral Resources Engineering Norwegian University of Science and Technology NorwayDepartment of Geology and Mineral Resources Engineering Norwegian University of Science and Technology Norway

Rana Gruber As is a mining company situated in northern Norway, just south of the artic circle. The hematite/magnetite ore is low grade, steeply dipping and intensively folded. The company excavates about 1.2 million tonnes of ore annually. The mining method is sublevel stoping. The final products are a hematite concentrate and different magnetite-products. The bits and bytes based methods and systems implemented for production planning and controlling are presented in the paper. Focus is on geological modelling, utilisation of variations in the deposit and associated uncertainty accumulating throughout the value chain. The methods and systems enable the mining department in greater extent than before, to deliver fragmented ore according to the specifications given by the processing plant.

关键词： mining geological variations uncertainty

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Unsuitable use of spin and pseudospin symmetries with a pseudoscalar Cornell potential

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Chinese Physics B 2014年第9期23卷 60-61页

作者： l.B.Castro A.s.de Castro Departamento de Física CFM Universidade Federal de Santa Catarina Departamento de Física Universidade Federal do Maranho Campus Universtitrio do Bacanga Departamento de Física e Química Campus de Guaratinguet Universidade Estadual Paulista

The concepts of spin and pseudospin symmetries has been used as mere rhetorics to decorate the pseudoscalar potential [Chin. Phys. B 22 090301 （2013）]. It is also pointed out that a more complete analysis of the bou... 详细信息

关键词： Dirac equation pseudoscalar Comell potential spin symmetry pseudospin symmetry

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Adaptive Grids in simulations of Toroidal Plasma starting from Magneto-Hydrodynamic Equilibrium

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Plasma science and Technology 2015年第2期17卷 97-104页

作者：李旭静 l.E.ZAKHAROV s.A.GAlKIN Institute of Computational Mathematics and scientific/Engineering Computing Academy of Mathematics and Systems ScienceChinese Academy of Sciences Princeton Plasma Physics laboratory FAR-TECH Inc. 10350 Science Center Dr.Bld 14St 150San DiegoCA 92121USA

This paper introduces the notion of Tokamak Magneto-Hydrodynamics （TMHD）, which explicitly reflects the anisotropy of a high temperature tokamak plasma. The set of TMHD equations is formulated for simulation of macroscopic plasma dynamics and disruptions in tokamaks. Free from the Courant restriction on the time step, this set of equations is adequate to plasma dynamics with realistic parameters of high performance plasmas and does not require any extension of the MHD plasma model. At the same time, TMHD requires the use of magnetic field aligned numerical grids. Examples of their use in 2-dimensional cases of tokamak equilibria and dynamics of the wall touching kink mode are presented. For the 3-dimensional case of an ergodic magnetic field, this paper introduces the reference magnetic coordinates as a practical algorithm for generating adaptive grids for TMHD.

关键词： tokamak magneto-hydrodynamics disruptions numerical simulations adaprive grid

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Development of a database for the prediction of phases in Pt-based superalloys:Cr-Pt-Ru

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Rare Metals 2006年第5期25卷 597-607页

作者： A.Watson l.A.Cornish R.süss Institute for Materials Research School of ProcessMaterials and Environmental EngineeringUniversity of LeedsLeedsUK Advanced Materials Division MintekPrivate Bag X3015Randburg2125South AfricaDST/NRF Centre of Excellence for Strong MaterialsUniversity of the WitwatersrandJohannesburg2025South Africa Advanced Materials Division MintekPrivate Bag X3015Randburg2125South AfricaDST/NRF Centre of Excellence for Strong MaterialsUniversity of the WitwatersrandJohannesburg2025South Africa School of Chemical and Metallurgical EngineeringUniversity of the WitwatersrandJohannesburg2025South Africa

Work has been ongoing in building a thermodynamic database for the prediction of phase equilibria in Pt-based superalloys. The alloys are being developed for high texture applications in aggressive environments. The database will aid the design of alloys by enabling the calculation of the composition and proportions of phases present in alloys of different compositions. In order to extend this database, a preliminary assessment of the Cr-Pt-Ru system has been undertaken, using a combination of Pandat and MTDATA software. As a first step, it was necessary to provide thermodynamic models for the three associated binary systems. Owing to a lack of thermodynamic information for these systems, the binary assessments were based on phase diagrams available in the literature. Using recent experimental phase equilibria data for the ternary system, a preliminary assessment of the Cr-Pt-Ru system has been produced. In this preliminary assessment, simplified models were employed for the l12 and sigma phases with a view to extending the descriptions as new experimental information becomes available.

关键词： Cr-Pt-Rh thermodynamics assessment phase diagram

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Free vibration and transient response of double curved beams connected by intermediate straight beams

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Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 37-62页

作者： R.A.JAFARI-TAlOOKOlAEI H.GHANDVAR E.JUMAEV s.KHATIR T.CUONG-lE school of Mechanical Engineering Babol Noshirvani University of Technology Department of Mechanical Engineering Faculty of Engineering New Uzbekistan University University of Business and science Center for Engineering Application and Technology solutions Ho Chi Minh City Open University

This paper investigates the free vibration and transient response of interconnected structures including double curved beams and intermediate straight beams,which are all constructed from functionally graded porous(FGP) materials. The strain potential and kinetic energies of each beam along with the work done by the external force are calculated. Additionally, a higher-order beam element is introduced to derive stiffness and mass matrices, along with the force vector. The curved and straight beams are discretized, and their assembled stiffness, mass matrices, and force vectors, are *** conditions at the joints are used to derive the total matrices of the entire structure. subsequently, the natural frequencies and transient response of the system are determined. The accuracy of the mathematical model and the self-developed computer program is validated through the comparison of the obtained results with those of the existing literature and commercial software ANsYs, demonstrating excellent ***, a comprehensive study is conducted to investigate the effects of various parameters on the free vibration and transient response of the considered structure.

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Interpenetrating polymers supported on microporous polypropylene membranes for the transport of chromium ions

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Chinese Journal of Chemical Engineering 2017年第7期25卷 938-946页

作者： Yesid Tapiero Julio sánchez Bernabél.Rivas Polymer Department Faculty of ChemistryUniversity of ConcepdonCasilla 160-C ConcepcionChile

Modifying polypropylene membranes with interpenetrating polymer networks(IPNs) through the incorporation of poly(glycidyl methacrylate-N-methyl-D-glucamine)(P(GMA-NMG)) was performed by in situ synthesis via radical polymerization. The surface of the polypropylene membrane was activated by hydrophilic grafted polyelectrolyte, and then, pressure injection was used for the impregnation of the reactive solution in the *** types of pore-filled membranes were synthesized, chelating interpenetrating homopolymer networks of P(GMA-NMG), and chelating-ion exchange interpenetrating polymer networks(e.g., P(GMA-NMG)/P(AA),P(GMA-NMG)/P(AMPsA), and P(GMA-NMG)/P(Cl VBTA)). After their synthesis, the modified polypropylene membranes were characterized using techniques such as the electrokinetic potential, sEM, FT-IR, and Donnan dialysis to corroborate the chromium ion transport. The P(GMA-NMG) and complex network membranes exhibited a hydrophilic character with a water-uptake capacity between 20% and 35% and a percentage of modification between 4.0% and 7.0% in comparison with the behavior of the unmodified polypropylene *** chromium ions were efficiently transported from the food chamber at p H 9.0 when the 65.2%MTA1 P(Cl VBTA) homopolymer IPN membrane and 48.5% MTAG P(GMA-NMG)/P(Cl VBTA) IPN membrane were used. similarly, hexavalent chromium ions were removed from the food chamber at pH 3.0 when MTAG(63.30%) and MTA1(35.68%) were used in 1 mol·l^(-1)Na Cl solution as the extraction reagent.

关键词： Polypropylene N-methyI-D-glucamine Ion exchange Donnan dialysis Interpenetrating polymer networks Chromium

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Re-visiting the mass-flux model for Explosive Reactive Armor and the effect of plate thickness

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Defence Technology（防务技术） 2019年第5期15卷 779-785页

作者： M.Mayseless s.Friling l.Misiuk Ben-Gurion University Beer-Sheva84105Israel Rafael P.O.Box 2250HaifaIsrael Matmon Unit Technological DivisionMil.P.O.Box 01154IDFIsrael

Explosive Reactive Armor was originally modeled under the assumption that the plates in the cassettes were very *** their thickness could be ignored,and the thicknesses of the plates were considered only based on their areal mass *** particular,it was assumed that the jet-plate interaction was controlled by the plates to jet-mass-flux ratio criteria for a specific jet velocity and *** the present study,we extended this analysis,examining the effect of the variation of the mass-flux along the jet on the disruption effect by the two *** addition,we examined the thickness effect of the plates on the plate's effectiveness,replacing the steel plates by low-density materials like aluminum and *** mass-flux model was adjusted to account for the plate-thickness *** was found that increasing the thickness of the plate,keeping the areal weight unchanged,slightly increases the overall effectiveness of the cassette,in particular by the forward moving plate interacting with the center and the slow parts of the jet.

关键词： Explosive reactive armor Armor shaped-charges Jet disruption

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Effect of Fuel to Oxidant Molar Ratio on structural and DC Electrical Conductivity of ZnO Nanoparticles Prepared by simple solution Combustion Method

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Journal of Materials science & Technology 2013年第10期29卷 898-902页

作者： C.s.Naveen M.l.Dinesha H.s.Jayanna Department of PG studies and Research in Physics Kuvempu University

ZnO nanoparticles of different sizes were prepared by varying the molar ratio of glycine and zinc nitrate hexahydrate as fuel and oxidizer （0.1, 0.8, 1.11, 1.3, 1.5, 1.7, 2.0） by simple solution combustion method. UV-Visible spectrophotometry studies show that, the band gap of the prepared ZnO nanoparticles increases with increasing fuel to oxidant （F/O） molar ratio up to 1.7 revealing the formation of ZnO nanoparticles. The decrease in band gap for the sample of F/O molar ratio 2.0 is due to an increase in particle size. Powder X-ray diffraction patterns of the prepared samples show the formation of single phase ZnO nanoparticles and the particle size decreases with increasing F/O molar ratio up to 1.7. surface morphology of the prepared samples was studied by scanning electron microscopy and it was observed that, the porosity increases with increasing F/O molar ratio. DC electrical conductivity at room temperature and in the temperature range of 303-563 K was studied for all the samples and the results revealed that, the sample of F/O molar ratio 1.7 has low electrical conductivity at room temperature and high EAR （high temperature activation energy） compared to other samples.

关键词： ZnO nanoparticles structural characterization Electrical conductivity

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Effect of specimen gauge reduction on uniaxial tension properties of reinforcing steel

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Journal of Iron and steel Research International 2020年第8期27卷 964-971页

作者： A.Triwiyono A.l.Han A.Aryanto s.Tudjono B.s.Gan Civil Engineering Department Gadjah Mada UniversitySleman 55283YogyakartaIndonesia Civil Engineering Department Diponegoro UniversityTembalang 50275SemarangIndonesia Civil Engineering Department Bandung Institute of TechnologyCoblong 40132BandungIndonesia Department of Architecture College of EngineeringNihon UniversityKoriyama 963-8642Fukushima PrefectureJapan

The standard Test Methods for Tension Testing of Metallic Materials (AsTM E8) mandates a specimen gauge reduction for obtaining the tensile properties of reinforcing steel bars. The standard outlines the specimen preparation requirements and methods to ensure that test results well represent the material properties. On the other hand, some codes differ regarding the approach to specimen preparation. They do not apply gauging, for both deformed and plain steel bars. Thus, the effect of specimen gauge reduction on the tensile properties of reinforcing steel bars was evaluated, and the interconnection of properties to the layer hardness was analysed. The experiment governed a range of deformed hot-rolled bar sizes, tested in tension using precision instruments. The Rockwell hardness test was implemented layerwise on the specimen’s cross section, and the hardness number (HRC) was measured as a function of the layer distance to the centre. A finite element model was constructed to study the stress concentrations induced by a constant indentation, simulating the HRCs, and to numerically construct the stress–strain relationship of ungauged steel bars based on the core properties and the section HRC relationship. scanning electron microscopy readings were performed to visually and chemically justify the results. It was shown that the specimen gauge reduction significantly influenced the resulting stress–strain behaviour of the material, and the yield and ultimate strengths were reduced. It was also demonstrated that the hardness response is proportional to the distance to the specimen’s axes. The corresponding yield and ultimate strengths thus increased accordingly, from the inner to the outer layers of the bar. Testing a gauged specimen will therefore result in lower strength than that of an ungauged steel bar.

关键词： Tensile property specimen gauge reduction Rockwell hardness number Finite element model Reinforcing steel

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