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A MIXED VIRTUAL ELEMEnT METHOD FOR The BOUSSInESQ PROBLEM On POLYGOnAL MESheS

Journal of Computational Mathematics 2021年第3期39卷 392-427页

作者： Gabriel n.Gatica mauricio Munar Filande. A.Sequeira CI^2 MA and Departamento de Ingenieria Matemitica Universidad de ConcepcionCasilla 160-CConcepcionChile Escuela de Matemaitica Universidad NacionalCampus Omar DengoHerediaCosta Rica

In this work we introduce and analyze a mixed virtual element method(mixed-VEM)for the two-dimensional stationary Boussinesq *** continuous formulation is based on the introduction of a pseudostress tensor depending nonlinearly on the velocity,which allows to obtain an equivalent model in which the main unknowns are given by the aforementioned pseudostress tensor,the velocity and the temperature,whereas the pressure is computed via a postprocessing *** addition,an augmented approach together with a fixed point strategy is used to analyze the well-posedness of the resulting continuous *** the discrete problem,we follow the approach employed in a previous work dealing with the.navier-Stokes equations,and couple it with a VEM for the convection-diffusion equation modelling the *** precisely,we use a mixed-VEM for the scheme associated with the fluid equations in such a way that the pseudostress and the velocity are approximated on virtual element subspaces of H(div)and H^(1),respectively,whereas a VEM is proposed to approximate the temperature on a virtual element subspace of H^(1).In this way,we make use of the L^(2)-orthogonal projectors onto suitable polynomial spaces,which allows the explicit integration of the terms that appear in the bilinear and trilinear forms involved in the scheme for the fluid *** the other hand,in order to manipulate the bilinear form associated to the heat equations,we define a suitable projector onto a space of polynomials to deal with the fact that the diffusion tensor,which represents the thermal conductivity,is ***,the corresponding solvability analysis is performed using again appropriate fixed-point ***,Strang-type estimates are applied to derive the a priori error estimates for the components of the virtual element solution as well as for the fully computable projections of them and the postprocessed *** corresponding rates of convergence are als

关键词： Boussinesq problem Pseudostress-based formulation Augmented formulation Mixed virtual element method.High-order approximations

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Cluster Partition Function and Invariants of 3-Manifolds

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Chinese Annals of Mathematics,Series B 2017年第4期38卷 937-962页

作者： mauricio ROMO School of-natural Sciences Institute for Advanced Study Princeton NJ 08540 USA.

The author reviews some recent developments in Che.n-Simons theory on a hyperbolic 3-manifold M with complex gauge group G. The author focuses on the case of G = SL(n, C) and M being a knot complement: M = S^3\ K. The main result presented in this note is the cluster partition function, a computational tool that uses cluster algebra techniques to evaluate the Che.n-Simons path integral for G = SL(n, C). he also reviews various applications and open questions regarding the cluster partition function and some of its relation with string theory.

关键词： Che.n-Simons theory Knots Cluster algebras

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Soft rocks in Argentina

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International Journal of Mining Science and Technology 2014年第6期24卷 883-892页

作者： Giambastiani mauricio national University of La Rioja La Rioja Argentina

Soft rocks are a still fairly unexplored chapter in rock mechanics. Within this category are the clastic sedimentary rocks and pyroclastic volcanic rocks, of low to moderate lithification （consolidation, cemen- tation, new formed minerals）, chemical sedimentary rocks and metamorphic rocks formed by minerals witk Mohs hardness less than 3.5, such as limestone, gypsum, halite, sylvite, between the first and phyllites, graphitic schist, chloritic shale, talc, etc., among the litter. They also include any type Of rock that suffered alteration processes （hydrothermal or weathering）. In Argentina the study of low-strength rocks has not received much attention despite having extensive outcrops in the Ande. and great impact in the design criteria. Correlation between geomechanical properties （UCS, deformability） to physical inde. （porosity, density, etc.） has shown promising results to be better studied. There are many studies and engineering projects in Argentina in soft rock geological environments, some cited in the text （Chihuido dam, n. Kirchner dam, J. Cepernic Dam, etc.） and others such as International Tunnel in the Province of Mendoza （Corredor Bioceanico）, which will require the valuable contribution from rock mechanics. The lack of consistency between some of the physical and mechanical parameters explored from studies in the country may be due to an insufficient amount of information and/or non-standardization of criteria for testing materials. It is unde.stood that more and better academic and professional efforts in improv- ing techniques will result in benefits to the better unde.standing of the geomechanics of weak rocks.

关键词： Soft rocks Argentine Tunnels Dams Rock parameters

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Relict glacial landscape in the Sierra Baguales Mountain Range(50°-51°S):evidence of glaciation dynamics and types in the eastern foothills of the southe.n Patagonian Ande.

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Journal of Mountain Science 2017年第2期14卷 282-295页

作者： ARAOS.JoséMiguel LE ROUX.Jacobus Philiphus GUTIERREZ.néstor mauricio Department of Geology FCFMUniversidad de ChilePlaza Ercilla#803SantiagoChile Department of Geography Faculty of Social Sciences.Universidad Alberto HurtadoUienfuegos#41SantiagoChile Department of Geology FCFMUniversidad de Chile.Andean Geothermal Centre of ExcellencePlaza Ereilla#803SantiagoChile

The glacial morphology of southe.n South American presents invaluable evidence to reconstruct former glacier behaviour and its relation to climate and environmental changes. However, there are still spatial and temporal gaps in the reconstruction of the Holocene Patagonian glacial landscape. here we present the first geomorphological record for the Sierra Baguales Mountain Range(SBMR), forming the eastern foothills of the Southe.n Patagonian Ande. 200 km from the Pacific coast. This area is topographically isolated from the Southe.n Patagonian Ice Field(SPIF), and is affected by the Westerly Winds. The study area shows evidence of ice sheet and alpine glaciations related to Ande.n uplift,which caused a marked climatic contrast between its western and eastern flanks since the Last Glacial Maximum(LGM). The regional rock mass strength and precipitation gradient acted as a controlling factor in the glacial cirque distribution and sizes, as well as in the development of glaciation types. We report new radiocarbon dates associated with warm/dry to cold/wet climatic changes during the middle Holocene, when former small alpine glaciers were located in the uppermost section of the SBMR basins, and eventually converged to form a small ice field or a composite valley glacier at lower *** can be explained by an estimated regional temperature drop of 3.8°C±0.8°C, based on a 585±26m Equilibrium Line Altitude(ELA) descent, inferred by geomorphological evidence and the Accumulation Area Ratio(AAR), in addition to a free-air adiabatic lapse rate. Subsequently, the glaciers receded due to climatic factors including a rise in temperature, as well as non-climatic factors, mainly the glacier bedrock topography.

关键词： Glacial morphology Sierra Baguales Ice sheet glaciations Alpine glaciations Middle Holocene

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Fast synthesis of gold nanoparticles by cold atmospheric pressure plasma jet in the presence of Au^(+) ions and a capping agent

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Plasma Science and Technology 2024年第7期26卷 108-115页

作者： Tatiana HABIB José mauricio A.CAIUT Bruno CAILLIER Laboratoire Diagnostics des Plasmas Hors Equilibre(DPhe) Universitéde ToulouseINU ChampollionAlbi 81000France Department of Chemistry The Nanomaterials and Luminescent Systems GroupFaculty of PhilosophyScience and Letters at Ribeirão PretoUniversity of São PauloRibeirão Preto-SP 14040-901Brazil

Homogeneous gold nanoparticles were synthesized unde. atmospheric pressure using a nonthermal helium plasma jet in a single-step process.A current power supply was used to generate the plasma discharge rich in diverse reactive *** species induce rapid chemical reactions responsible for the reduction of the gold salts upon contact with the liquid *** this study,spherical and monodispersed gold nanoparticles were obtained within 5 min of plasma exposure using a solution containing gold(Ⅲ)chloride hydrate(HAuCl_(4))as a precursor and polyvinylpyrrolidone(PVP)as a capping agent to inhibit *** formation of these metal nanoparticles was initially perceptible through a visible change in the sample's color,transitioning from light yellow to a red/pink *** was subsequently corroborated by UVvis spectroscopy,which revealed an optical absorption in the 520-550 nm range for Au nPs,corresponding to the surface plasmon resonance(SPR)*** investigation into the impact of various parameters,including plasma discharge duration,precursor and capping agent concentrations,was carried out to optimize conditions for the formation of well-separated,spherical gold *** light scattering(DLS)was used to measure the size of these nanoparticles,transmission electron microscopy(TEM)was used to observe their morphology and X-ray diffraction(XRD)was also employed to determine their crystallographic *** results confirm that homogeneous spherical gold nanoparticles with an average diameter of 13 nm can be easily synthesized through a rapid,straightforward,and environmentally friendly approach utilizing a helium atmospheric pressure plasma.

关键词： gold nanoparticles non-thermal plasma jet helium DBD

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Data Center Power System Stability-Part I: Power Supply Impedance Modeling

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CSEE Journal of Power and Energy Systems 2022年第2期8卷 403-419页

作者： Jian Sun Mingchun Xu mauricio Cespedes Mike Kauffman Rensselaer Polytechnic Institute-ECSE 1108th Street Room CII 8015Troy 12180United States Meta Platforms Inc. 1601 Willow RdMenlo ParkCalifornia 94025-1452United States

This two-part paper presents methods to predict,characterize and ensure the stability of data center power systems based on impedance *** work was motivated by recent power system resonance incidents in new data *** I presents new input impedance models for single-phase power supply units(PSUs)to enable this *** impedance models of single-phase PSU cannot meet the requirements of this application because they exclude DC voltage control that affects system stability at low frequency,or are in a dq reference frame that cannot handle the complexity of data center power *** developed new models include DC bus dynamics and are directly in the phase domain to simplify system stability analysis,avoiding the.need for multiple-input-multiple-output(MIMO)system models and the generalized nyquist criterion that are difficult to apply but necessary with dq-frame *** the converter and system level models also include the coupled current response that is characteristic of AC-DC converters and important for system stability at low *** simple form of the models and system stability analysis directly in the phase domain also make it possible to develop new PSU design methods and performance specifications that together will ensure the stability of new data center power *** developed models are validated by laboratory measurements and are used in Part II of the work to study data center power system stability.

关键词： Data center power systems frequency-domain methods impedance modeling system stability system resonance

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A charged star with geometric Karmarkar condition

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Communications in Theoretical Physics 2023年第8期75卷 139-149页

作者： Gabino Estevez-Delgado Joaquin Estevez-Delgado Rafael Soto-Espitia Antonio Rendón Romero Jorge mauricio Paulin-Fuentes Facultad de Químico Farmacobiología de la Universidad Michoacana de San nicolás de Hidalgo Facultad de Ciencias Físico Matemáticas de la Universidad Michoacana de San nicolás de Hidalgo Edificio BCiudad Universitaria Facultad de Ingeniería Civil de la Universidad Michoacana de San nicolás de Hidalgo Edificio A Ciudad Universitaria Facultad de Ingeniería Mecánica de la Universidad Michoacana de San nicolás de Hidalgo Edificio W Ciudad Universitaria División Académica de Ciencias Básicas de la Universidad Juárez Autónoma de Tabasco

In this paper,we analyse an analytical solution of the Einstein–Maxwell field equations that considers matter with anisotropic pressures in a static and spherically symmetric *** report the manner in which we obtained the solution,which is by means of the Karmarkar *** the model,we assume a state equation that describes the interaction of matter from quarks P=(c^(2)ρ-4B_(g))/3 and we consider the presence of electric charge,which can generate that the radial and tangential pressures are not *** a graphic manner,we analyse the physical properties of the model,taking as the observational data those of mass 1M⊙and radius7.69 km which were reported for the star her *** charge values are found between 5.57×10^(18)C≤Q≤1.31×10^(20)C and the interval of the Bag constant Bg∈[118.7,122.13]MeV/fm^(3).Also,we show the stability of the configuration by means of the static stability criteria of Harrison–Zeldovich–novikov((?M)/?ρc>0),as well as in regards to infinitesimal radial adiabatic perturbation,since the adiabatic inde.γ>3.3 which guarantees the stability of the solution.

关键词： general relativity exact solutions anisotropic fluid Karmarkar condition

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基于嵌入式离散裂缝建模的Eagle Ford页岩油复杂水力裂缝综合表征

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石油勘探与开发 2021年第3期48卷 613-619页

作者： FIALLOS mauricio MORALES Adrián YU Wei MIAO Jijun 德克萨斯大学奥斯汀分校西德布莱德石油与地质工程系德克萨斯78712美国 SimTech有限责任公司休斯顿77494美国切萨皮克(Chesapeake)公司俄克拉荷马73154美国

使用嵌入式离散裂缝建模(EDFM)方法优化具有复杂裂缝系统的油藏的数值模拟,完善了前人的Eagle Ford页岩油综合描述技术。根据裂缝支撑类型对具有100000多个裂缝面的复杂裂缝系统进行分类后,对井底流压进行了历史拟合,对油田产量进行了预... 详细信息

使用嵌入式离散裂缝建模(EDFM)方法优化具有复杂裂缝系统的油藏的数值模拟,完善了前人的Eagle Ford页岩油综合描述技术。根据裂缝支撑类型对具有100000多个裂缝面的复杂裂缝系统进行分类后,对井底流压进行了历史拟合,对油田产量进行了预测,以更深入地了解复杂裂缝支撑效果对产量的影响。在为不同支撑类型裂缝组分配不同的压实曲线后估算的压降表明,如果采用EDFM方法而不是非结构网格方法进行裂缝建模和筛选,裂缝模型表达更精确,有效波及面积可能会小于非结构网格方法。方法优化后,能够将EDFM与第三方裂缝扩展模拟器自动耦合,同时考虑支撑剂强度沿复杂裂缝系统的变化。该方法能够从裂缝评价和多个全井眼的拟三维裂缝扩展结果中准确地模拟复杂的裂缝延伸和井间干扰,从而更准确地评价完井效果。

关键词：嵌入式离散裂缝建模复杂裂缝水力裂缝裂缝网络油藏模拟页岩油

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Gastric cancer research in Mexico:A public health priority

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World Journal of Gastroenterology 2014年第16期20卷 4491-4502页

作者： Clara Luz Sampieri mauricio Mora Instituto de Salud Pública Universidad VeracruzanaAv. Luis Castelazo AyalaCol. Industrial ánimas91190 XalapaVeracruzMéxico Facultad de Medicina Universidad Veracruzana.Médicos y OdontólogosCol. Virginia Cordero91120 XalapaVeracruzMéxico

This study aimed review studies conducted on Mexican patients diagnosed with gastric cancer and/or diseases associated with its development,in which at least one Mexican institute has participated,and to assess their contributions to the primary and secondary prevention of this disease.A search of the Medline database was conducted using the following keywords:gastric/stomach cancer,*** of the Mexican population were selected in which at least one Mexican Institute had participated and where the findings could support public policy proposals directed towards the primary or secondary prevention of gastric *** the148 studies found in the Medline database,100 were discarded and 48 were *** to the analysis presented,these studies were classified as:epidemiology of gastric cancer(5/48);risk factors and protectors relating to gastric cancer(9/48);relationship between helicobacter pylori and pathologies associated with gastric cancer and the development of the disease(16/48);relationship between the Epstein-Barr virus and pathologies associated with gastric cancer and the development of the disease(3/48);molecular markers for the development of diseases associated with gastric cancer and gastric cancer(15/48).Mexico requires a program for the prevention and control of gastric cancer based on national health *** should be produced by a multidisciplinary committee of experts who can propose actions that are relevant in the current national *** few studies of gastric cancer conducted on the Mexican population in national institutes highlight the poor connection that currently exists between the scientific community and the health sector in terms of resolving this health *** policies for health research should support projects with findings that can be translated into benefits for the *** review serves to identify national research groups studying gastric cancer in the Mexican population.

关键词： Gastric cancer Mexico Research Prevention Public health

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Virtual Conductance Based Cascade Voltage Controller for VSCs in Islande. Operation Mode

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Journal of Modern Power Systems and Clean Energy 2022年第6期10卷 1704-1713页

作者： Francisco Jesús Matas-Díaz Manuel Barragán-Villarejo Juan Carlos Olives-Camps Juan Manuel mauricio JoséMaría Maza-Ortega Department of Elec‐trical Engineering Universidad de SevillaSeville 41092Spain

Voltage source converters have become the main enabler for the integration of distributed energy resources in *** the case of islande. operation,these devices normally set the amplitude and frequency of the.network voltage by means of a cascade controller composed of an outer voltage control loop and an inner current control *** strategies to compute the gains of both control loops have been proposed in the literature in order to obtain a fast and decoupled response of the voltages at the point of common *** paper proposes an alternative and simple methodology based on the introduction of a virtual conductance in the classic cascade *** strategy allows to design each control loop inde.ende.tly,obtaining a closed-loop response of a first-order *** this way,the gains of each control loop are easily derived from the parameters of the LC coupling filter and the desired closed-loop time ***,a state observer is included in the controller to estimate the inductor current of the LC filter in order to reduce the.number of required measurements.A laboratory testbed is used to validate and compare the proposed *** experimental results demonstrate the effectiveness of the proposal both in steady-state and transient regimes.

关键词： Voltage source converter microgrid cascade controller virtual conductance

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