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Influence of wire spacing and plate spacing on electrostatic precipitation of nanoparticles: An approach involving electrostatic shielding and diffusion charging

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Particuology 2023年第9期80卷 127-139页

作者： felipe de Aquino Lima Vádila Giovana Guerra Department of Chemical Engineering Federal University of São CarlosRodovia Washington LuísKm 235C.P.676CEP 13560-970São CarlosSPBrazil

Electrostatic precipitation is a process widely used as gas cleaning device,to removal particles from gas ***,in a conventional and well-sized precipitator,the collection efficiency decreases for ultrafine particles,making it difficult to employ this equipment for controlling nanoparticle *** paper investigates the influence of plate spacing(4 and 6.5 cm)and wire spacing(4,6,and 12 cm)on the electric current and nanoparticle collection efficiency,considering the effect of diffusion charging and electrostatic *** laboratory-scale dry wire-plate electrostatic precipitators with different plate spacings were tested for the collection of nanoparticles(6.15–241.4 nm)at three air velocities(1.9,2.9,and 3.9 cm/s).The results demonstrated the effectiveness of the equipment in removing nanoparticles(99.9%)under the highest electric *** values of the wire spacing led to increases in the current and the collection *** was associated with reduced electrostatic shielding,which is more evident in smaller ducts with a higher density of field *** is expected that the findings should improve knowledge on electrostatic precipitation of nanoparticles,enabling optimization of collection efficiency by considering the effects of geometric parameters.

关键词： Electrostatic precipitation Nanoparticles Collection efficiency Plate spacing Wire spacing

Plumbing System of Hunga Tonga Hunga Ha'apai Volcano

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Journal of Earth Science 2023年第3期34卷 706-716页

作者： Román alvarez Miguel Camacho Instituto de Investigaciones en Matemáticas Aplicadas y en Sistemas(IIMAS) Universidad Nacional Autónoma de MéxicoCoyoacán CDMX 04510Mexico Posgrado en Ciencias de la Tierra Universidad Nacional Autónoma de MéxicoCoyoacán CDMX 04510Mexico

The Hunga Tonga Hunga Ha’apai submarine volcano has experienced repeated eruptions in the latest *** recent one,in January 2022,released an enormous amount of energy inducing global perturbations,as tsunamis and atmospheric *** structure of the volcano is poorly understood,especially its internal ***-seated magmatic connections are difficult to define or *** use a high-resolution gravity data set obtained via satellite to calculate the Bouguer anomaly over its structure,to perform a preliminary exploration of its *** 3D gravity inversions,we find a complex plumbing system with various exhaust trajectories and multiple surface pockets of low-density material within the volcanic edifice;some appear to be associated with ring *** is in line with the report of the 2009 eruption,described as beginning from multiple *** found no signs of a magma chamber within 6 km depth,although several volcanic conduits are identified from such depth to the *** variations occur within a plumbing conduit or may vary from one conduit to another in the same *** models yield quantitative estimates for areas of magma-water interaction,constituting a baseline to compare with structural changes to be induced in future eruptions.

关键词： Hunga Tonga Hunga Ha'apai satellite gravity data 3D inversions volcano Tofua Island

Parallel array with axially coded light-sheet microscope

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Light(Science & Applications) 2020年第1期9卷 1387-1388页

作者： Pablo Loza-alvarez ICFO-The Institute of Photonic Sciences The Barcelona Institute of Science and Technology08860 CastelldefelsBarcelonaSpain

A parallel array of frequency modulated light sheets results in a scanning-less light sheet microscope capable of fast volumetric imaging.

关键词： array light axial

Inequalities for the Extended Best Polynomial Approximation Operator in Orlicz Spaces

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Acta Mathematica Sinica,English Series 2019年第2期35卷 185-203页

作者： Sonia ACINAS Sergio FAVIER felipe ZO Departamento de Matemática Facultad de Ciencias y Exactas NaturalesUniversidad Nacional de La Pampa Instituto de Matemática Aplicada San Luis IMASLUniversidad Nacional de San Luis and CONICET Departamento de Matemática Universidad Nacional de San Luis

In this paper we pursue the study of the best approximation operator extended from L~Φ to L~φ, where φ denotes the derivative of the function Φ. We get pointwise convergence for the coefficients of the extended best approximation polynomials for a wide class of function f, closely related to the Calder′on–Zygmund class t_m^p(x) which had been introduced in 1961. We also obtain weak and strong type inequalities for a maximal operator related to the extended best polynomial approximation and a norm convergence result for the coefficients is derived. In most of these results, we have to consider Matuszewska–Orlicz indices for the function φ.

关键词： Orlicz spaces extended best polynomial approximation pointwise and norm convergence weak and strong type inequalities Orlicz indices

The effect of ethanol fuel dilution on oil performance and MoDTC tribofilms formation and composition

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Friction 2024年第9期12卷 2108-2125页

作者： Juan RUIZ-ACERO felipe KESSLER Henara COSTA Tiago COUSSEAU Polytechnic School Universidade de São PauloSão Paulo 05508-030Brazil School of Food and Chemistry Universidade Federal do Rio GrandeRio Grande 96203-000Brazil School of Engineering Universidade Federal do Rio GrandeRio Grande 96203-900Brazil Mechanical Engineering Department Univ.Tecnológica Federal do ParanáCuritiba 81280-340Brazil University of Newcastle CallaghanSW 2308Australia

Ethanol has emerged as a promising alternative to fossil fuels,but its use can lead to significant dilution in lubricants,particularly during cold start or heavy *** dilution can affect the performance of additives,including friction modifiers like molybdenum dithiocarbamate(MoDTC),which are designed to reduce friction under extreme contact *** research suggests that ethanol may impact the performance of MoDTC,prompting this study’s goal to investigate the effects of ethanol on MoDTC tribofilms and their friction response under boundary lubrication ***,reciprocating tribological tests were performed with fully formulated lubricants containing MoDTC with varying ethanol *** results indicate that a critical ethanol dilution level inhibits friction reduction by MoDTC activation,resulting in friction coefficients(COFs)similar to the base *** tested with simple mixtures of polyalphaolefin(PAO)+MoDTC showed increased COFs with added *** of tested surfaces using Raman spectroscopy,X-ray photoelectron spectroscopy(XPS),and X-ray absorption spectroscopy near the edge structure(XANES)revealed the presence of sulfates,MoO_(3),MoS_(2),and MoS_(x)O_(y)compounds in the tribofilms formed on the surfaces,with and without ethanol diluted in the ***,the addition of ethanol increased the sulfates and MoO_(3)content of the tribofilms at the expense of friction-reducing compounds such as MoS_(2)and MoS_(x)O_(y).These findings suggest that ethanol dilution in lubricants containing MoDTC creates an oxygen-rich interfacial medium that favors the formation of compounds with insufficient friction-reducing capabilities.

关键词： molybdenum dithiocarbamate(MoDTC) ethanol tribofilm friction modifier additive lubricant

Analyzing the energy intensity and greenhouse gas emission of Canadian oil sands crude upgrading through process modeling and simulation

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Frontiers of Chemical Science and Engineering 2014年第2期8卷 212-218页

作者： Anton alvarez-MAJMUTOV Jinwen CHEN Natural Resources Canada CanmetENERGY One Oil Patch Drive Devon AB T9G 1A8 Canada

This paper presents an evaluation of the energy intensity and related greenhouse gas/CO2 emissions of integrated oil sands crude upgrading processes. Two major oil sands crude upgrading schemes currently used in Canadian oil sands operations were investigated： cokingbased and hydroconversion-based. The analysis, which was based on a robust process model of the entire process, was constructed in Aspen HYSYS and calibrated with representative data. Simulations were conducted for the two upgrading schemes in order to generate a detailed inventory of the required energy and utility inputs： process fuel, steam, hydrogen and power. It was concluded that while hydroconversion-based scheme yields considerably higher amount of synthetic crude oil （SCO） than the cokerbased scheme （94 wt-% vs. 76 wt-%）, it consumes more energy and is therefore more CO2-intensive （413.2kg CO2/m3sco vs. 216.4kg CO2/m^3sco）. This substantial difference results from the large amount of hydrogen consumed in the ebullated-bed hydroconverter in the hydroconversion-based scheme, as hydrogen production through conventional methane steam reforming is highly energy-intensive and therefore the major source of CO2 emission. Further simulations indicated that optimization of hydroconverter operating variables had only a minor effect on the overall CO2 emission due to the complex trade-off effect between energy inputs.

关键词： Oil sands crude upgrading hydroconversion,process modeling greenhouse gas emissions

Dendrimer nanocarriers drug action: perspective for neuronal pharmacology

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Neural Regeneration Research 2015年第7期10卷 1029-1031页

作者： felipe Vidal Leonardo Guzman Laboratory of Molecular Neurobiology Department of PhysiologyFaculty of Biological Sciences University of Concepcion

General aspects：Currently,several strategies have been used to overcome common problems found in pharmacological therapies,such as insolubility,reduced bioavailability and low specificity of *** of the most promising alternatives proposed is the use of dendrimeric drug nanocarriers,polymeric chemical structures of diverse nature that contain,transport and deliver the desired drug in biological systems.

关键词： PAMAM perspective for neuronal pharmacology

Predicting coastal morphological changes with empirical orthogonal function method

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Water Science and Engineering 2016年第1期9卷 14-20页

作者： fernando alvarez shun-qi pan Hydro-environmental Research Centre School of Engineering Cardiff University Cardiff CF24 3AA UK

In order to improve the accuracy of prediction when using the empirical orthogonal function （EOF） method, this paper describes a novel approach for two-dimensional （2D） EOF analysis based on extrapolating both the spatial and temporal EOF components for long-term prediction of coastal morphological changes. The approach was investigated with data obtained from a process-based numerical model, COAST2D, which was applied to an idealized study site with a group of shore-parallel breakwaters. The progressive behavior of the spatial and temporal EOF components, related to bathymetric changes over a training period, was demonstrated, and EOF components were extrapolated with combined linear and exponential functions for long-term prediction. The extrapolated EOF components were then used to reconstruct bathymetric changes. The comparison of the reconstructed bathymetric changes with the modeled results from the COAST2D model illustrates that the presented approach can be effective for long-term prediction of coastal morphological changes, and extrapolating both the spatial and temporal EOF components yields better results than extrapolating only the temporal EOF component.

关键词： EOF method Coastal morphological change Long-term prediction Process-based numerical model Shore-parallel breakwater

Cellular automata model for traffic flow with safe driving conditions

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Chinese Physics B 2014年第5期23卷 216-226页

作者： María Elena Lárraga Luis alvarez-Icaza Instituto de Ingeniería Universidad Nacional Autónoma de México04510Coyoacán D.F.México

In this paper, a recently introduced cellular automata （CA） model is used for a statistical analysis of the inner micro-scopic structure of synchronized traffic flow. The analysis focuses on the formation and dissolution of clusters or platoons of vehicles, as the mechanism that causes the presence of this synchronized traffic state with a high flow. This platoon formation is one of the most interesting phenomena observed in traffic flows and plays an important role both in manual and automated highway systems （AHS）. Simulation results, obtained from a single-lane system under periodic boundary conditions indicate that in the density region where the synchronized state is observed, most vehicles travel together in pla- toons with approximately the same speed and small spatial distances. The examination of velocity variations and individual vehicle gaps shows that the flow corresponding to the synchronized state is stable, safe and highly correlated. Moreover, results indicate that the observed platoon formation in real traffic is reproduced in simulations by the relation between vehicle headway and velocity that is embedded in the dynamics definition of the CA model.

关键词： traffic flow models synchronized traffic cellular automata platoons formation