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Numerical Approach of a Coupled Pressure-Saturation Model describing Oil-Water Flow in Porous Media

Communications on Applied Mathematics and Computation 2023年第2期5卷 946-964页

作者： Paula Luna Arturo Hidalgo ISIS Neutron and Muon Source Rutherford Appleton LaboratoryDidcot OX110QXUK departamento de ingeniería Geológica y Minera Escuela Técnica Superior de Ingenieros de Minas y EnergíaCenter for Computational SimulationUniversidad Politécnica de MadridRíos Rosas2128003 MadridSpain

Two-phase flow in porous media is a very active field of research,due to its important applications in groundwater pollution,CO_(2)sequestration,or oil and gas production from petroleum reservoirs,just to name a few of them.Fractional flow equations,which make use of Darcy's law,for describing the movement of two immiscible fluids in a porous medium,are among the most relevant mathematical models in reservoir simulation.This work aims to solve a fractional flow model formed by an elliptic equation,representing the spatial distribution of the pressure,and a hyperbolic equation describing the space-time evolution of water saturation.The numerical solution of the elliptic part is obtained using a finite-element(FE)scheme,while the hyperbolic equation is solved by means of two dif-ferent numerical approaches,both in the finite-volume(FV)framework.One is based on a monotonic upstream-centered scheme for conservation laws(MUSCL)-Hancock scheme,whereas the other makes use of a weighted essentially non-oscillatory(ENO)reconstruc-tion.In both cases,a first-order centered(FORCE)-αnumerical scheme is applied for inter-cell flux reconstruction,which constitutes a new contribution in the field of fractional flow models describing oil-water movement.A relevant feature of this work is the study of the effect of the parameterαon the numerical solution of the models considered.We also show that,in the FORCE-αmethod,when the parameterαincreases,the errors diminish and the order of accuracy is more properly attained,as verified using a manufactured solution technique.

关键词： Two-phase flow Reservoir simulation Porous media FORCE-α Finite volume

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Spectrophotometric determination of the formation constants of Calcium(Ⅱ) complexes with 1,2-ethylenediamine,1,3-propanediamine and 1,4-butanediamine in acetonitrile

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Green Energy & Environment 2017年第1期2卷 51-57页

作者： Jacqueline González González Mónica Nájera-Lara Varinia López-Ramírez Juan Antonio Ramírez-Vázquez José J.N.Segoviano-Garfias Programa de Maestría en Biociencias División de Ciencias de la Vida (DICIVA) Universidad de Guanajuato Campus Irapuato-Salamanca Colegio del Nivel Medio Superior de Salamanca(ENMS) departamento de ingeniería Bioquímica Instituto Tecnológico Superior de Irapuato (ITESI) departamento de Ciencias Ambientales División de Ciencias de la Vida (DICIVA) Universidad de Guanajuato Campus Irapuato-Salamanca

In this work, with the purpose to explore the coordination chemistry of calcium complexes which could work as a partial model of manganese-calcium cluster, a spectrophotometric study to evaluate the stability of the complexes: Calcium(Ⅱ)-1,2-ethylendiamine, Calcium(Ⅱ)-1,3-propanediamine and Calcium(Ⅱ)-1,4-butanediamine in acetonitrile, were carried on. By processing the spectrophotometric data with the HypSpec program allows the determination of the formation constants. The logarithmic values of the formation constants obtained for Calcium(Ⅱ)-1,2-ethylendiamine, Calcium(Ⅱ)-1,3-propanediamine and Calcium(Ⅱ)-1,4-butanediamine were log β_(110) = 4.69, log β_(110)= 5.25 and log β_(110) = 4.072, respectively.

关键词： Calcium(Ⅱ)complexes Solution equilibria Artificial photosynthesis Absorbance molar Speciation

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Alternative approaches for estimating missing climate data:application to monthly precipitation records in South- Central Chile

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Forest Ecosystems 2018年第4期5卷 390-399页

作者： Alonso Barrios Guillermo Trincado Rene Garreaud Escuela de Graduados Facultad de Ctencias Forestales y Recursos Naturales Universidad Austral de ChileBox 567ValdiviaChile departamento de Ciencias forestales Facuitad de Ingenieria ForestalUnlversidad del Tolima Box 6299 Ibague Colombia Instituto de Bosques y Sociedad Facultad de Ciencias Forestales y Recursos NaturalesUniversidad Austraide ChileBox 567 ValdiviaChile departamento de Geofistca Facultad de Ciencias Fisicas y MatematicasUniversidad de ChileSantiagoChile

Background: Over the last decades interest has grown on how climate change impacts forest resources. However,one of the main constraints is that meteorological stations are riddled with missing climatic data. This study compared five approaches for estimating monthly precipitation records: inverse distance weighting(IDW), a modification of IDW that includes elevation differences between target and neighboring stations(IDW_m), correlation coefficient weighting(CCW), multiple linear regression(MLR) and artificial neural networks(ANN).Methods: A complete series of monthly precipitation records(1995-2012) from twenty meteorological stations located in central Chile were used. Two target stations were selected and their neighboring stations, located within a radius of25 km(3 stations) and 50 km(9 stations), were identified. Cross-validation was used for evaluating the accuracy of the estimation approaches. The performance and predictive capability of the approaches were evaluated using the ratio of the root mean square error to the standard deviation of measured data(RSR), the percent bias(PBIAS), and the NashSutcliffe efficiency(NSE). For testing the main and interactive effects of the radius of influence and estimation approaches,a two-level factorial design considering the target station as the blocking factor was used.Results: ANN and MLR showed the best statistics for all the stations and radius of influence. However, these approaches were not significantly different with IDW_m. Inclusion of elevation differences into IDW significantly improved IDW_m estimates. In terms of precision, similar estimates were obtained when applying ANN, MLR or IDW_m, and the radius of influence had a significant influence on their estimates, we conclude that estimates based on nine neighboring stations located within a radius of 50 km are needed for completing missing monthly precipitation data in regions with complex topography.Conclusions: It is concluded that approaches based on ANN, MLR and IDWm had the best performance in two s

关键词： Climatological data Cross-validation Artificial neural networks Multiple linear regression

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Structured-illumination reflectance imaging for the evaluation of microorganism contamination in pork: Effects of spectral and imaging features on its prediction performance

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Food Science and Human Wellness 2024年

作者： Binjing Zhou Xiaohua Liu Yan Ge Kang Tu Jing Peng Juan Francisco García-Martín Jie Wu Weijie Lan Leiqing Pan The Academy of Science Nanjing Agricultural University College of Engineering Nanjing Agricultural University College of Food Science and Technology Nanjing Agricultural University School of Food and Biological Engineering Bengbu University departamento de ingeniería Química Facultad de Química Universidad de Sevilla

Structured-illumination reflectance imaging provides a new means for food quality detection. This original work investigated the capability of Structured-illumination reflectance imaging technique coupled with multivariate chemometrics to evaluate the microbial contamination in pork inoculated with Pseudomonas fluorescens and Brochothrix thermosphacta during storage at different temperatures. The prediction performances based on different spectrum and the textural features of direct component and amplitude component images demodulated from the SIRI pattern images， as well as their data fusion were comprehensively compared. Based on the full wavelength spectrum (420 – 700) nm of amplitude component images， the orthogonal signal correction coupled with support vector machine regression provided the best predictions of the number of Pseudomonas fluorescens and Brochothrix thermosphacta in pork， with the Rp2values of 0.870 and 0.906， respectively. Besides， the prediction models based on the amplitude component or direct component image textural features and the data fusion models using spectrum and textural features from direct component and amplitude component images cannot significantly improve their prediction accuracy. Consequently， structured-illumination reflectance imaging can be further considered as a potential technique for the rapid evaluation of microbial contaminations in pork meat.

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Biomass gasification,catalytic technologies and energy integration for production of circular methanol:New horizons for industry decarbonisation

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Journal of Environmental Sciences 2024年第6期140卷 306-318页

作者： Luis F.Bobadilla Lola Azancot Miriam González-Castañ Estela Ruíz-López Laura Pastor-Pérez Francisco J.Durán-Olivencia Runping Ye Katie Chong Paula HBlanco-Sánchez Zenthao Wu Tomás R.Reina JoséA.Odriozola departamento de Química Inorgánica e Instituto de Ciencia de Materiales de Sevilla Centro Mixto CSIC-Universidad de SevillaAvda.Américo Vespucio 49Sevilla 41092Spain departamento de ingeniería Universidad Loyola AndalucíaAvda.de Las Universidades s/nSevilla 41704Spain Key Laboratory of Jiangxi Province for Environment and Energy Catalysis School of Chemistry and Chemical EngineeringNanchang UniversityNanchang330031China Energy and Bioproducts Research Institute(EBRI) Aston UniversityBirminghamB47ETUnited Kingdom department of Chemical and Process Engineering University of SurreyGuildfordGU27XHUnited Kingdom

The Intergovernmental Panel on Climate Change(IPCC)recognises the pivotal role of renewable energies in the future energy system and the achievement of the zero-emission target.The implementation of renewables should provide major opportunities and enable a more secure and decentralised energy supply system.Renewable fuels provide long-term solutions for the transport sector,particularly for applications where fuels with high energy density are required.In addition,it helps reducing the carbon footprint of these sectors in the long-term.Information on biomass characteristics feedstock is essential for scaling-up gasification from the laboratory to industrial-scale.This review deals with the transformation biogenic residues into a valuable bioenergy carrier like biomethanol as the liquid sunshine based on the combination of modified mature technologies such as gasification with other innovative solutions such as membranes and microchannel reactors.Tar abatement is a critical process in product gas upgrading since tars compromise downstream processes and equipment,for this,membrane technology for upgrading syngas quality is discussed in this paper.Microchannel reactor technology with the design of state-of-the-art multifunctional catalysts provides a path to develop decentralised biomethanol synthesis from biogenic residues.Finally,the development of a process chain for the production of(i)methanol as an intermediate energy carrier,(ii)electricity and(iii)heat for decentralised applications based on biomass feedstock flexible gasification,gas upgrading and methanol synthesis is analysed.

关键词： Biogenic residues Gasification Biomethanol Circular Economy Microreactors

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Sharp Interpolation Inequalities on the Sphere:New Methods and Consequences

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Chinese Annals of Mathematics,Series B 2013年第1期34卷 99-112页

作者： Jean DOLBEAULT Maria J. ESTEBAN Michal KOWALCZYK Michael LOSS Ceremade Université Paris DauphinePlace de Lattre de Tassigny departamento de ingeniería Matemática and Centro de Modelamiento Matemático (UMI 2807 CNRS) Universidad de Chile Skiles Building Georgia Institute of Technology

This paper is devoted to various considerations on a family of sharp interpolation inequalities on the sphere, which in dimension greater than 1 interpolate between Poincaré, logarithmic Sobolev and critical Sobolev (Onofri in dimension two) inequalities. The connection between optimal constants and spectral properties of the Laplace-Beltrami operator on the sphere is emphasized. The authors address a series of related observations and give proofs based on symmetrization and the ultraspherical setting.

关键词：插值球体 Sobolev 不等式夏普光谱特性最佳常数庞加莱

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增材制造Ti6Al4V合金的闪速等离子体电解氧化与在生理介质中的电化学行为

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Transactions of Nonferrous Metals Society of China 2024年第4期34卷 1150-1166页

作者： H.MORA-SANCHEZ C.RAMOS M.MOHEDANO B.TORRES R.ARRABAL E.MATYKINA departamento de ingeniería Química y de Materiales Facultad de Ciencias QuímicasUniversidad Complutense de Madrid28040 MadridSpain CIdeTEC Basque Research and Technology Alliance(BRTA)Po.Miramón 19620014 Donostia-San SebastiánSpain departamento Matemática Aplicada Ciencia e Ingeniería de Materiales y Tecnología ElectrónicaUniversidad Rey Juan CarlosC/Tulipán s/nMóstoles 28933MadridSpain

研究激光粉末床熔融增材制造(AM)(又称直接金属激光烧结)技术制备的Ti6Al4V合金等离子体电解氧化(PEO)处理及其电化学行为。通过短时间(<120 s)PEO处理(也称闪速PEO),在AM合金和传统合金表面制备了3~10μm厚、含Ca和P的涂层。然后在改... 详细信息

研究激光粉末床熔融增材制造(AM)(又称直接金属激光烧结)技术制备的Ti6Al4V合金等离子体电解氧化(PEO)处理及其电化学行为。通过短时间(<120 s)PEO处理(也称闪速PEO),在AM合金和传统合金表面制备了3~10μm厚、含Ca和P的涂层。然后在改良的α-MEM溶液中,通过动电位极化曲线和电化学阻抗谱(EIS)评估了合金的电化学行为。与传统合金相比,AM合金中形成了细小的层片状α显微组织和层间小尺寸的β相颗粒,这促使了火花的产生,从而促进了PEO涂层的生长。闪速PEO涂层提高了传统合金和AM合金的耐腐蚀性,最薄的涂层(<3μm)提供了高达3倍的保护。AM Ti6Al4V由于其高的晶界密度,易受局部缝隙腐蚀的影响。而即使短至35 s的闪速PEO处理也足以成功避免这种情况。

关键词：增材制造激光粉末床熔融等离子体电解氧化闪速PEO 钛缝隙腐蚀 α-MEM

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Type Ⅱ Blow-up in the 5-dimensional Energy Critical Heat Equation

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Acta Mathematica Sinica,English Series 2019年第6期35卷 1027-1042页

作者： Manuel del PINO Monica MUSSO Jun Cheng WEI department of Mathematical Sciences University of Bath departamento de ingeniería Matemática-CMM Universidad de Chile departamento de Matemáticas Universidad Católica de Chile department of Mathematics University of British Columbia

We consider the Cauchy problem for the energy critical heat equation ■ in dimension n = 5. More precisely we find that for given points q_1, q_2,..., q_k and any sufficiently small T > 0 there is an initial condition u0 such that the solution u(x, t) of(0.1) blows-up at exactly those k points with rates type Ⅱ, namely with absolute size ～(T-t)^(-α) for α >3/4. The blow-up profile around each point is of bubbling type, in the form of sharply scaled Aubin–Talenti bubbles.

关键词： Singularity formation bubbling phenomena critical parabolic equations

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detection of DC series arc in more electric aircraft power system based on optical spectrometry

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High Voltage 2020年第1期5卷 24-29页

作者： Jun Jiang Mingxin Zhao Zhe Wen Chaohai Zhang Ricardo Albarracín Center for More Electric Aircraft Power System Nanjing University of Aeronautics and AstronauticsNanjing 211106People's Republic of China departamento de ingeniería Eléctrica ElectrónicaAutomática y Física AplicadaEscuela Técnica Superior de Ingeniería y Diseño IndustrialUniversidad Politécnica de MadridRonda de Valencia 328012 MadridSpain

Series arcing faults have been recognised as a hazardous phenomenon in the power system of more electric aircraft(MEA),especially with the increasing voltage level and power supply.Instead of the electrical method,the optical method can be used as an approach to detect arc fault with the advantages of fast response and immunity to electromagnetic interference.It is the basis of optical arc detection to determine the distribution spectrum range of direct current(DC)arc fault.Aiming at series arc optical detection in the MEA DC system,a DC series arc test platform was established to measure the series arc spectrum.The spectrum was disassembled though empirical mode decomposition to extract characteristic wavelengths of arc light and denoised by means of wavelet decomposition and reconstruction(wavelet transformation)to reduce equipment noise.To resolve the baseline drift,the baseline of the arc spectrum measured was calculated and corrected based on Savitzky−Golay.The experimental results indicate that there are several series arc characteristic spectra of the MEA DC system,including 309.3 and 324.5 nm in the ultraviolet range.Moreover,the arc spectrum with different metals,copper and aluminium,were contrasted,indicating the arc spectral behaviour is related to the melting/boiling point and chemical properties of the anode material.The measurement of the series arc spectrum makes it more effective to apply optical detection in the MEA discharging faults diagnosis.

关键词： power system series

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Oxidative degradation of Thermoplastic Starch Induced by UV Radiation

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Journal of Renewable Materials 2019年第4期7卷 383-391页

作者： Mayte M.Quispe Olivia V.López Marcelo A.Villar Planta Piloto de ingeniería Química PLAPIQUI(UNS CONICET)Bahía Blanca(8000)Argentina departamento de ingeniería Química Universidad Nacional del Sur(UNS)Bahía Blanca(8000)Argentina

Among biopolymers,thermoplastic starch(TPS)is a good candidate to obtain biomaterials because of its natural origin,biodegradable character,and processability.Exposure to ultraviolet(UV)radiation causes significant degradation of starch-based materials,inducing photooxidative reactions which result in breaking of polymer chains,production of free radical,and reduction of molar mass.These changes produce a deterioration of TPS mechanical properties,leading to useless materials after an unpredictable time.In this work,changes induced on TPS by UV radiation,analyzing structural properties and mechanical behavior,are studied.TPS was obtained through thermo-mechanical processing of native corn starch in the presence of water(45%w/w)and glycerol(30%w/w)as plasticizers.Films were obtained by thermocompression and,before testing,specimens were conditioned to reduce material fragility.Photodegradation process was performed by exposing TPS to 264 h UV radiation in a weathering test chamber.Specimen’s weight loss was determined gravimetrically.Chemical changes were studied by Fourier Transform Infrared Spectroscopy(FTIR)and morphological modifications were analyzed by Scanning Electron Microscopy(SEM).Reduction of weight average molar mass was measured by Static Light Scattering(SLS).Changes in mechanical properties were studied from tensile tests.After 96 h exposure,TPS specimens presented a weight reduction of 4-6%,mainly attributed to plasticizers lost by evaporation.SEM observations showed that UV radiation induced morphological changes on TPS,evidenced by an increment of specimens cracking.By FTIR,it was detected the presence of an additional band located at 1726 cm-1 in samples submitted to UV radiation,attributed to the formation of-C=O groups.Weight average molar mass of native starch was in the order of 107 g mol-1.TPS exposure to UV radiation decreased significantly its molar mass,confirming molecular degradation of the biopolymer.When TPS was exposed during 48 h,it was detected a considerable decrease in elongati

关键词： Thermoplastic starch UV radiation structural properties mechanical behavior

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