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Advances in Materials Physics and Chemistry 2012年第4期2卷 92-95页

作者： Y elvia díaz valdés Concepción Mejía García Ana María Paniagua Mercado Arturo Méndez sánchez departamento de Física Escuela Superior de Física y Matemáticas – IPN Edif. 9 UPALM Col. San Pedro Zacatenco Deleg. GAM México 07737 México

Actually recent investigation in developing semiconducting-superconducting composites based in Cds and Bi-based superconductors has attracted interest in processing thin superconducting films. In this work are reported Bi-Pb-sr-Ca-Cu-O (BPsCCO) thin films grown on MgO substrates by spray pyrolysis technique from a solution containing Bi(NO3)3, Pb(NO3)2, sr(NO3)2, Ca(NO3)2 and Cu(NO3)2, with a subsequent solid state reaction for growing the Bi-based superconducting phases. Annealed films were characterized by X-ray diffraction, atomic absorption spectroscopy and resistance measurements. Interdependence between Pb content, annealing time and temperature, in the formation of superconducting phases was studied applying a fractional factorial design 3III4-2. Interrelation between Pb content, ta and Ta exists. The presence of Pb is necessary to stabilize the high-Tc phase but its content depends on the annealing conditions.

关键词： superconductivity BPsCCO superconducting Films spray Pyrolysis deposition Pb Content Annealing Conditions Experimental design

development And Characterization of Ultra Low Cement Castable Cordierites by Thixotropic Properties Mixtures

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Advances in Materials Physics and Chemistry 2012年第4期2卷 96-98页

作者： Ana M. Paniagua-Mercado Arturo Méndez-sánchez elvia díaz valdés Concepción Mejía García depto. de Física Escuela Superior de Física y Matemáticas Instituto Politécnico Nacional Col. Lindavista CP 03778 México D. F. México

The main target in this investigation was to take advantage of the reology properties of the tixotropic mixes in Ultra Low Cement Castables (ULCC). The cordierite phase in refractory mix can be obtained using raw materials with magnesium oxide in its composition, such as, Mg(OH)2 or H2Mg3(siO3)4 (Talc mineral), with a content of? 63.5% siO2, 31.7% MgO and 4.8% H2O. In this investigation, as magnesium source, a commercial calcined magnesite with 90% MgO was used.? This mineral was selected instead of Talc mineral, because this last contains more impurities in its composition that tend to form more amounts of liquid phases with low fusion points. For this work two different ULCC mixes were designed. These were fired at 1260 oC, the cordierite phase was quantified in each mix.

关键词： Reology Thixotropic Mixtures Ultra Low Cement Castables Cordierite

synthesis of Aluminum-doped Zinc Oxide Nanowires Hydrothermally Grown on Plastic substrate

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Advances in Materials Physics and Chemistry 2012年第4期2卷 56-59页

作者： Concepción Mejía García elvia díaz valdés Ana Ma. Paniagua Mercado Arturo F. Méndez sánchez José A. Andraca Adame Velumani subramaniam Josué Romero Ibarra Centro de Nanociencias y Micro y Nanotecnologías del IPN UPALM Luis Enrique Erro S/N México 07738 México departamento de Física Escuela Superior de Física y Matemáticas – IPN Edif. 9 UPALM Col. San Pedro Zacatenco Deleg. GAM México 07738 México depto. de Ing. Eléctrica Sección de Estado Sólido Av. IPN No. 2508 Col. San Pedro Zacatenco México 07360 México

We report the synthesis of undoped ZnO and Al-doped ZnO (ZnO:Al) nanowires grown using a two-step process: (a) preparation of the seed layer, and (b) growth of the nanostructures. In the first step,? 10 mM solutions of zinc acetate dihydrate and 1-propanol were spin coated on polyethylene terephthalate? (PET) substrate at 2000 rpm by 30 s. Vertical nanowires were then grown by dipping the substrates in an equimolar solution of zinc nitrate hexahydrate and hexamethylenetetramine. As doping source, aluminum nitrate nonahydrate powders were added in the solution. In the solutions, Al doping concentrations were established as 0.5 At %, 1.0 At %, 2.0 At % and 3.0 At %, respectively. The hydrothermal process were carried out with a commercially microwave at 140 W power setting. The nanowires were characterized optically and morphologically. XRd patterns show the presence of ZnO, Zn(OH)2 and Zn6Al2O9. scanning electron microscopy analysis showed that the size of ZnO nanowires was 50 nm in diameter. The undoped ZnO and ZnO:Al nanowires bandgap energy was obtained from optical transmission spectra.

关键词： Nanowires ZnO ZnO:Al Nanowires spin Coating Hydrothermal Process

Modeling and multi-objective optimization of a gasoline engine using neural networks and evolutionary algorithms

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Journal of Zhejiang University-science A(Applied Physics & Engineering) 2013年第9期14卷 657-670页

作者： Joséd. MARTíNEZ-MORALEs elvia R. PALACIOs-HERNáNdEZ Gerardo A. VELáZQUEZ-CARRILLO Faculty of Engineering Autonomous University of San Luis PotosiSan Luis Potosi 78290 Mexico Faculty of science Autonomous University of San Luis PotosiSan Luis Potosi 78290 Mexico Mechatronics department Monterrey Institute of Technology and Higher EducationMexico D. F. 01389 Mexico

In this paper, a multi-objective particle swarm optimization （MOPsO） algorithm and a nondominated sorting genetic algorithm II （NsGA-II） are used to optimize the operating parameters of a 1.6 L, spark ignition （sI） gasoline engine. The aim of this optimization is to reduce engine emissions in terms of carbon monoxide （CO）, hydrocarbons （HC）, and nitrogen oxides （NOx）, which are the causes of diverse environmental problems such as air pollution and global warming. stationary engine tests were performed for data generation, covering 60 operating conditions. Artificial neural networks （ANNs） were used to predict exhaust emissions, whose inputs were from six engine operating parameters, and the outputs were three resulting exhaust emissions. The outputs of ANNs were used to evaluate objective functions within the optimization algorithms： NsGA-II and MOPsO. Then a decision-making process was conducted, using a fuzzy method to select a Pareto solution with which the best emission reductions can be achieved. The NsGA-II algorithm achieved reductions of at least 9.84%, 82.44%, and 13.78% for CO, HC, and NOx, respectively. With a MOPsO algorithm the reached reductions were at least 13.68%, 83.80%, and 7.67% for CO, HC, and NOx, respectively.

关键词： Engine calibration Multi-objective optimization Neural networks Multiple objective particle swarm optimization(MOPsO) Nondominated sorting genetic algorithm II (NsGA-II)

spatial patterns of distribution and abundance of Harrisia portoricensis,an endangered Caribbean cactus

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Journal of Plant Ecology 2013年第6期6卷 489-498页

作者： Julissa Rojas-sandoval elvia J.Meléndez-Ackerman department of Biology University of Puerto RicoRío Piedras CampusPO Box 23360San JuanPuerto Rico 00931-3360USA Center for Applied Tropical Ecology and Conservation University of Puerto RicoPO Box 70377San JuanPuerto Rico 00936-8377USA department of Environmental sciences College of Natural SciencesUniversity of Puerto RicoPO Box 70377San JuanPuerto Rico 00936-8377USA

Aims The spatial distribution of biotic and abiotic factors may play a dominant role in determining the distribution and abundance of plants in arid and semiarid *** this study,we evaluated how spatial patterns of microhabitat variables and the degree of spatial dependence of these variables influence the distribution and abundance of the endangered cactus Harrisia *** We used geostatistical analyses of five microhabitat variables(*** cover,soil cover and light incidence)and recorded the abundance of *** in 50 permanent plots established across Mona Island,Puerto Rico,by the United states department of Agriculture Forest service as part of the Forest Inventory and Analysis(UsdA–FIA).We also used partial Mantel tests to evaluate the relationships between microhabitat variables and abundance of ***,controlling for spatial *** findings Abundance of *** showed strong affinities with microhabitat variables related to canopy structure,soil cover and light *** distribution of this cactus species throughout the island was consistent with the spatial variation patterns of these *** general,landscape-level analyses suggested a predictive value of microhabitat traits for the distribution and abundance of this endangered *** sensitive cacti species,wherein abundance may be influenced by similar variables,these types of analyses may be helpful in developing management plans and identifying critical habitats for conservation.

关键词： abundance Caribbean cactus geostatistics Harrisia portoricensis Mona Island spatial correlation spatial distribution

design optimization of multilayer perceptron neural network by ant colony optimization applied to engine emissions data

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science China(Technological sciences) 2019年第6期62卷 1055-1064页

作者： MARTINEZ-MORALEs Jose QUEJ-COsGAYA Hector LAGUNAs-JIMENEZ Jose PALACIOs-HERNANdEZ elvia MORALEs-sALdANA Jorge Faculty of Engineering Autonomous University of Campeche Campeche 24039 Mexico Faculty of sciences Autonomous University of San Luis Potosi San Luis Potosi 78290 Mexico Faculty of Engineering Autonomous University of San Luis Potosi San Luis Potosi 78290 Mexico

A multilayer perceptron(MLP) artificial neural network(ANN) model has been optimized by the multi-objective ant colony optimization(MOACO) algorithm, which uses three objective functions. A sensitivity analysis to choose MOACO parameter values is carried out by calculating hypervolume metric, and the proposed approach adopts the Vlsekriterijumska Optimizacija I Kompromisno Resenje(VIKOR) decision method to choose final compromised solution on the Pareto front obtained from MOACO. As a result, we used the MLP-MOACO developed model to estimate the value of engine emissions of NOxin a four stroke, spark ignition(sI) gasoline engine and observed acceptable correlation coefficient(R^2) of 0.99978.

关键词： ant colony optimization multilayer perceptron artificial neural networks hypervolume engine emissions

Influence of Humidity on Yield stress determination by slump Test of slip-Prone Clayey soils and Their Relation with the Chemical Properties

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Advances in Materials Physics and Chemistry 2012年第4期2卷 102-105页

作者： Arturo F. Méndez-sánchez Ana M. Paniagua-Mercado Karen E. Nieto-Zepeda Leonor Pérez-Trejo elvia diaz valdés Concepción Mejía García Escuela superior de Física y Matemáticas Instituto Politécnico Nacional Edif. 9 Unidad Profesional Adolfo López Mateos Col. Lindavista C. P. 07738 México D. F. México.

In this work, the yield stress evaluation as a function of water content for slip-prone clayey soils is studied in order to understand how yield stress decreases as water content increases, and their relation with the chemical properties. The clayey soil samples were taken from the region of Teziutlán-Puebla-Mexico. Yield stress was calculated using the slump test in cylindrical geometry. Results show three zones. The first one shows an exponential decrement on yield stress due to lower water content in accord with clayey soils with high content of illita, followed by a second region where yield stress decreases dramatically at a certain critical water concentration, and the third one where yield stress dependence is not well-defined since the clayey soil flow is seen. Finally, it is discussed how yield stress variation due to the water increment influences the landslide risk increment.

关键词： Clayey soil Yield stress slump Test Microstructure Illita

Ecological Zonation of Phytoplankton and Biomass Based on Bio-Optical Parameters off Baja California during Three summer seasons

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Open Journal of Marine science 2019年第3期9卷 121-136页

作者： sánchez-Pérez elvia denisse Millán-Núnez Eduardo department of Marine Ecology Centro de Investigación Científica y de Educación Superior de EnsenadaEnsenadaMéxico department of Plankton and Marine Ecology CONACyT-Instituto Politécnico Nacional-Centro Interdisciplinario de Ciencias MarinasLa PazMéxico

An ecological zonation of phytoplankton was determined from its normalized spectral absorption shape (aphn) during the summers of 2001-02-03 off the west coast of Baja California. In the first two seasons, the highest abundances of the main taxonomic groups of phytoplankton were detected towards the coastal stations, but for 2003, diatoms showed higher abundances towards the oceanic region. The ecological provinces (Pv) were the footprint of the zonation in the structure of the phytoplankton community;likewise, it was observed that the spectral shape was independent of the chlorophyll-a (mg·m-3). The effect of coastal upwelling south of Vizcaíno Bay favored the increase of phytoplankton cells. However, the composition of the community decreased in cells abundance and diversity due to the influence of the phenomenon called El Nino “débil” reported to the south of the California Current for the years 2002-03.

关键词： Ecological Zonation Phytoplankton Bio-Optics El Nino débil

重症监护室护士限制治疗努力的能力:整合性综述

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International Journal of Nursing sciences 2024年第1期11卷 143-154,I0003页

作者： elvia R.Lopez-Panza Vanessa C.Pacheco-Roys Kelly J.Fernandez-Ahumada diana C.díaz-Mass María Y.Exposito-Concepcion Elizabeth Villarreal-Cantillo Cesar I.Aviles Gonzalez Nursing department Universidad del NorteBarranquillaColombia Nursing Program Faculty of Health SciencesUniversidad Popular del CesarValleduparColombia Clínica Valledupar ValleduparColombia Hospital Universidad del Norte SoledadColombia department of Medical sciences and Public Health University of CagliariCittadella Universitaria di MonserratoCagliariItaly

目的在重症监护病房(IntensiveCareUnit,ICU),护土难免会遇到需要限制治疗努力(limiting therapeutie efort,LTE)的患者,尽管多数护士还缺乏为这些临终患者及其家庭提供支持的准备。本综述旨在描述ICU护士在LTE中需要具备的能力。方法对... 详细信息

目的在重症监护病房(IntensiveCareUnit,ICU),护土难免会遇到需要限制治疗努力(limiting therapeutie efort,LTE)的患者,尽管多数护士还缺乏为这些临终患者及其家庭提供支持的准备。本综述旨在描述ICU护士在LTE中需要具备的能力。方法对2010年--2023年发表的文献进行综述。系统检索了5个数据库:Medline、Wiley Online Library、sciELO、sciencedirect和Web of science。使用关键评估项目工具西班牙语版(Critical Appraisal skills Programme in spanish,CAsPe)作为评判性阅读工具。使用牛津循证医学中心(Center for Evidence-Based Medicine.,CEBM)评估工具确定证据级别和推荐强度。结果共纳入25篇文献。ICU护士LTE护理的能力包括对患者的直接护理、以家庭为中心的护理以及护士在团队中的作用。该综述确定了3个类别的能力:作为患者、家庭与跨学科团队之间维护者的能力,在LTE方面的决策能力,在患者生命末期治疗和护理干预的能力。结论ICU护士在LTE方面需要具备相应的能力,这对患者的生活质量死亡尊严以及患者家庭应对悲伤的全面支持至关重要。

关键词：重症监护家庭支持重症监护病房护士的作用安宁疗护专业能力

Non-thermal plasma for exhaust gases treatment

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Frontiers of Mechanical Engineering 2015年第3期10卷 301-305页

作者： elvia ALVA R. Marquidia PACHECO P.l Fernando GOMEZ B. Joel PACHECO P. Arturo COLIN C Victor sANCHEZ-MENdIETA Ricardo valdIVIA B Alfredo sANTANA d. Jose HUERTAs C Hilda FRIAs P. Instituto Nacional de Investigaciones Nucleates Ocoyoacac 52750Mexico Universidad Autonoma del Estado de Mexico Toluca 50000 Mexico Instituto Tecnologico y de Estudios superiores de Monterrey CampusToluca 50110 Mexico

This article describes a study on a non-thermal plasma device to treat exhaust gases in an internal combustion engine. several tests using a plasma device to treat exhaust gases are conducted on a Honda GX200- 196 cm3 engine at different rotational speeds. A plasma reactor could be efficient in degrading nitrogen oxides and particulate matter. Monoxide and carbon dioxide treatment is minimal. However, achieving 1%-3% degradation may be interesting to reduce the emission of greenhouse gases.

关键词： plasma treatment NOx CO CO2 particulatematter vehicle