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Solid Particle Erosion of AISI 304 SS Caused by Alumina Particles

Journal of Surface Engineered Materials and Advanced Technology 2024年第1期14卷 1-14页

作者： Juan Rodrigo Laguna-Camacho Celia María Calderón-Ramón víctor velázquez-martínez Javier Calderón-Sánchez Gabriel Juárez-Morales Cristóbal Cortez-Domínguez Jorge Alberto Chagoya-Ramírez Jesús Enrique López-Calderón Paul Ramírez-Sánchez Silvia Marina Sánchez-Yáñez Héctor Daniel López-Calderón Faculty of Electrical and Mechanical Engineering Universidad Veracruzana Poza Rica Veracruz Mexico Facultad de Ciencias Biolgicas y Agropecuarias Universidad Veracruzana Tuxpan Veracruz Mexico Facultad de Biologa Universidad Veracruzana Xalapa Veracruz Mexico

This research work was carried out with the aim of continuing to expand knowledge on the behaviour of AISI 304 stainless steel against solid particle erosion. In this particular case, the steel was subjected to the impact of alumina particles, which are hard abrasives with irregular and angular shapes. Different characterization techniques were applied to gain a better understanding of alumina. For instance, particle size distribution was obtained using the Analysette 28 Image Sizer and the particle size was between 300 - 400 µm. SEM and EDS analysis were used to know the morphology and chemical composition of both the abrasive particles and AISI 304 stainless steel. Additionally, mechanical properties values such as the hardness and Young’s modulus of AISI 304 steel were attained using a Berkovich indenter (model TTX-NHT, CSM Instruments). On the other hand, two tests were carried out for each impact angle used, 30˚, 45˚, 60˚ and 90˚, with a particle velocity of 24 ± 2 m/s and an abrasive flow rate of 63 ± 0.5 g/min, employing a test rig based on ASTM G76-95 standard. SEM images using two detectors, Backscattered Electron Detector (BED) and Low Electron Detector (LED), were employed to identify the wear mechanisms on the AISI 304 eroded surfaces at 30˚ and 90˚. Finally, the erosion rates of AISI 304 compared to those results reached by AISI 1018 steel and AISI 420 stainless steel tested under identical conditions in previous works.

关键词： Solid Particle Erosion AISI 304 Stainless Steel Alumina Particles Wear Mechanisms Erosion Rates

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Effect of initial microstructure on austenite formation kinetics in high-strength experimental microalloyed steels

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International Journal of Minerals,Metallurgy and Materials 2015年第12期22卷 1304-1312页

作者： Edgar López-martínez Octavio vázquez-Gómez Héctor Javier vergara-Hernández Bernardo Campillo Faculty of Chemistry Metallurgical Engineering Department Autonomous National University of Mexico National Council for Science and Technology Metallurgy Science Postgraduate Programme Morelia Institute of Technology Institute of Physical Sciences Autonomous National University of Mexico

Austenite formation kinetics in two high-strength experimental microalloyed steels with different initial microstructures comprising bainite-martensite and ferrite-martensite/austenite microconstituents was studied during continuous heating by dilatometric analysis. Austenite formation occurred in two steps：（1） carbide dissolution and precipitation and （2） transformation of residual ferrite to austenite. Dilatometric analysis was used to determine the critical temperatures of austenite formation and continuous heating transformation diagrams for heating rates ranging from 0.03°C.s^-1 to 0.67°C.s^-1. The austenite volume fraction was fitted using the Johnson-Mehl-Avrami-Kolmogorov equation to determine the kinetic parameters k and n as functions of the heating rate. Both n and k parameters increased with increasing heat- ing rate, which suggests an increase in the nucleation and growth rates of austenite. The activation energy of austenite formation was determined by the Kissinger method. Two activation energies were associated with each of the two austenite formation steps. In the first step, the austenite growth rate was controlled by carbon diffusion from carbide dissolution and precipitation; in the second step, it was controlled by the dissolution of residual ferrite to austenite.

关键词： non-isothermal kinetics microalloyed steel austenite heating dilatometry

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Subaxial cervical spine injury classification system: is it most appropriate for classifying cervical injury?

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Neural Regeneration Research 2015年第9期10卷 1416-1417页

作者： Rafael martínez-Pérez Francisco Fuentes víctor S.Alemany Division of Neurosurgery Department of Clinical Neurological Sciences University of Western Ontario Department of Neurology Hospital Rafael Méndez School of Medicine Universidad Complutense

The cervical spine injury represents a potential devastating disease with 6% associated in-hospital mortality （lain et al., 2015）. Neurological deterioration ranging from complete spinal cord injury （SCI） to incomplete SCI or single radiculopathy are potential consequences of the blunt trauma over this region. The subaxial cervical spine accounts the vast majority of cervical injuries, making up two thirds of all cervical fractures （Alday, 1996）. Few classifications （Holdsworth, 1970; White et al., 1975; Mien et al., 1982; Denis, 1984; vaccaro et al., 2007） have been proposed to describe injuries of the cervical spine for several reasons. First, to delineate the best treatment in each case; second, to determinate an accurate neurological prognosis, and third, to establish a standard way to communicate and describe specific characteristics of cervical injuries patterns. Classical systems are primarily descriptive and no single system has gained widespread use, largely because of restrictions in clinical relevance and its complexity.

关键词： is it most appropriate for classifying cervical injury SLIC Subaxial cervical spine injury classification system

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A regionalized IO-model to value seasonal recreational ecosystem services in a mountain National Park in Spain

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Journal of Mountain Science 2022年第1期19卷 211-227页

作者： víctor martIN BARROSO Mónica de CASTRO-PARDO Pascual FERNÁNDEZ martÍnez João C.AZEvEDO Department of Applied Economics I and history and economic institutions Faculty of Law and Social SciencesUniversidad Rey Juan CarlosCampus of VicálvaroTulipanMóstoles 28933Spain Department of Financial and Actuarial Economics and Statistics-Statistics and Operational Research Complutense University of MadridCampus of SomosaguasPozuelo de Alarcon 28223Spain Centro de Investigação de Montanha Instituto Politécnico de BragançaCampus de Santa ApolóniaBragança 5300-253Portugal

Recreational Ecosystem Services(RES)are among the most frequently evaluated ecosystem *** are seen as a major opportunity for sustainable development in areas of high ecological value resulting from the presence of emblematic species,habitats or scenery,often integrated in conservation areas,in particular in mountain areas affected by depopulation,rising environmental risks and ***,the assessment of RES has been based on Contingent valuation and Choice Experiments,methods with limitations related to their ***,Input-Output(IO)models provide a very accurate and effective way of valuation of RES with regional information regarding interindustry *** data on nature tourist expenditure may be only available annually,tourism inflows have a strong seasonal behavior,which impacts the profitability of several local economic *** this paper,we firstly constructed a novel regionalized IO-model based on Cross-Industry Location Quotients using employment data and,secondly,based on Monte Carlo simulation,we estimated nature tourist expenditure monthly using data on nature tourism *** method allowed for a more precise RES evaluation,estimating direct,indirect and induced monthly economic impacts of nature-based *** method was applied to the Ordesa and Monte Perdido(OMP)National Park in the Spanish *** estimate the average tourist expenditure,we collected and analyzed spending on commerce,hospitality and restaurants,leisure,and transport of 385 *** suggest that using a regionalized IO model leads to a considerable reduction of over-estimation of the economic impact of tourist expenditure estimated by conventional *** into consideration the direct,indirect and induced effects of tourist expenditure in 2016-2018,the total annual output effect in the OMP National Park amounted to€208.8 million,while the total income effect amounted to€86.29 ***,a total of

关键词： Input-Output Monte Carlo Simulation Location quotients Recreational Ecosystem Services Nature tourism Sustainable mountain development

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Geochemistry and mineralogy of beach sediments in the northern Gulf of Mexico,Tamaulipas state,Mexico:implication for provenance

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Journal of Palaeogeography 2024年第3期13卷 375-400页

作者： Mayank Shukla Sanjeet K.verma Mayla A.Ramos-vázquez John S.Armstrong-Altrin Karla R.Hernández-martínez Sumit Mishra vivek P.Malviya Héctor Hernández-Mendoza Posgrado de la Division de Geociencias Aplicadas Instituto Potosino de Investigacion Científica y Tecnologica(IPICYT)Camino a la Presa San José2055San Luis Potosí78216Mexico Division de Geociencias Aplicadas Instituto Potosino de Investigación Científica y Tecnologica(IPICYT)Camino a la Presa San Jose 2055San Luis Potosí78216Mexico Universidad Nacional Autonoma de México Instituto de Ciencias del Mar y LimnologíaUnidad de ProcesosOceanicos y CosterosCiudad UniversitariaCiudad de México 04510Mexico Department of Marine Sciences Bharathidasan UniversityTiruchirappalli620024Tamil NaduIndia Instituto de Geociencias Universidad Nacional Autonoma de MéxicoBoulevard Juriquilla 300176230JuriquillaQueretaroMexico Department of Applied Geology Dr.Harisingh Gour Central UniversitySagar470002Madhya PradeshIndia Instituto de Investigacion de Zonas Desérticas Universidad Autònoma de San Luis PotosíAltair 200CP 78377San LuisS.L.P.Mexico Universidad del Centro de Mexico Capitán Caldera 75CP 78250San LuisS.L.P.Mexico

Geochemical and mineralogical studies were performed in the La Pesca(LP)and Tesoro Altamira(TA)beach sediments,located in the Tamaulipas state,northern Gulf of *** main aim of this study is to infer the weathering history and provenance and to discriminate the tectonic environment of the beach *** sediments are composed of quartz with small amounts of accessory minerals such as plagioclase,calcite,orthoclase,microcline,and *** beach sediments are classified as fine-grained and very well sorted,however LP has coarse skewed and leptokurtic sediments,whereas TA has fine-skewed and very leptokurtic *** chemical index of weathering(CIW’)indicates intense weathering in the source *** quartz grain microtextures in the LP and TA are classified into mechanical,chemical,and mechanical/chemical *** features such as fractures,pits,percussion marks,abrasion fatigue,and v-shaped marks favor high-energy littoral,fluvial,subaqueous-marine,and aeolian *** chemical features indicate solution pits and crystalline overgrowth,which suggests a silica saturated marine *** mechanical/chemical features display adhering particles and elongated depressions suggest formation in a sub-aqueous nearshore marine *** and trace elements-based provenance discrimination diagrams indicate a felsic source derived from the Mesa Central(MC),Sierra Madre Oriental(SMOr)and Oaxaquia *** major and trace element concentrations imply a passive margin setting for the northern Gulf of Mexico,which is consistent with the general geology.

关键词： Beach sediments Geochemistry Mineralogy Provenance Tamaulipas Tectonic setting

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Physiopathology of ischemic stroke and its modulation using memantine:evidence from preclinical stroke

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Neural Regeneration Research 2021年第3期16卷 433-439页

作者： Hilda martínez-Coria Isabel Arrieta-Cruz María-Esther Cruz Héctor E.López-valdés División de Investigación Facultad de MedicinaUniversidad Nacional Autónoma de México(UNAM)Ciudad de MéxicoMéxico Laboratorio Experimental de Enfermedades Neurodegenerativas Facultad de MedicinaUNAM/Instituto Nacional de Neurología y NeurocirugíaCiudad de MéxicoMéxico Departamento de Investigación Básica Instituto Nacional de GeriatríaCiudad de MéxicoMéxico Unidad de Investigación en Biología de la Reproducción Laboratorio de NeuroendocrinologíaFacultad de Estudios Superiores ZaragozaUNAMCiudad de MéxicoMéxico Unidad Periférica de Neurociencia Facultad de MedicinaUNAM/Instituto Nacional de Neurología y NeurocirugíaCiudad de MéxicoMéxico

Ischemic stroke is the most common type of cerebrovascular disease and is caused by an interruption of blood flow in the *** this disease,two different damage areas are identifying:the lesion core,in which cells quickly die;and the penumbra(surrounding the lesion core),in which cells are functionally weakened but may recover and restore their *** currently approved treatments for ischemic stroke are the recombinant tissue plasminogen activator and endovascular thrombectomy,but they have a short therapeutic window(4.5 and 6 hours after stroke onset,respectively)and a low percentage of stroke patients actually receive these *** is an approved drug for the treatment of Alzheimer's *** is a noncompetitive,low affinity and use-dependent antagonist of N-methyl-D-aspartate glutamate *** has several advantages over developing a new drug to treat focal ischemic stroke,but the most important is that it has sufficient safe probes in preclinical models and humans,and if the preclinical studies provide more evidence about pharmacological actions in tissue protection and repair,this could help to increase the number of clinical *** present review summarizes the physiopathology of isquemic stroke and the pharmacological actions in neuroprotection and neuroplasticity of memantine in the post stroke stage of preclinical stroke models,to illustrate their potential to improve functional recovery in human patients.

关键词： focal ischemic stroke memantine neuroplasticity neuroprotection stroke therapy

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Bedrock outcropping in the accumulation zone of the largest glacier in Mexico(Glaciar Norte of Citlaltépetl),as evidence of a possible accelerated extinction

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Journal of Mountain Science 2023年第2期20卷 338-354页

作者： SOTO víctor Colegio de Geografía Facultad de EconomíaUniversidad VeracruzanaAv.Xalapa s/nObrero Campesina91020XalapaVer.México

The highest volcano in Mexico,at the same time the third largest mountain in North America(Citlaltépetl,5610 m a.s.l.),is home to the largest glacier in the *** of the extinction of the Popocatépetl glacier(5500 m a.s.l.)caused by eruptive activity,and the almost disappearance of the Iztaccíhuatl glaciers(5220 m a.s.l.)due to the lower elevation of the mountain,the Glaciar Norte of Citlatépetl has been the only glacier that has shown a certain degree of stability as a response to the altitude in which it is ***,as occurs in almost all glaciers on the planet,the retreat of its glacier terminus has been ***,during the last years the thickness of its upper part began to decrease rapidly until its bedrock was exposed for the first time in *** to its ecosystem importance and because it is the main glacier in Mexico,as well as the only one in the world located at latitude 19°N,in this work its current dimensions are updated,as well as the local climatology that governs the current state of the glacier is pointed *** study was based on the analysis of high-resolution Sentinel-2 optical images,as well as through Sentinel-1 SAR images,with the support of climatological information from the study ***,the outcropping of the bedrock in the accumulation zone and the consequent horizontal retreat of the upper part of the glacier are documented;at the same time,the decrease in the thickness of the ice along it is *** rocky outcrop in the accumulation zone suggests that the flow dynamics of the ice towards the ablation zone will be considerably less,accelerating the retreat of the glacier ***,the ascent of the glacial front to 5102 m *** the modelled altitude of the equilibrium line to 5276 m *** reported as a warning signal in terms of snow catchment and mass balance;likewise,the decrease of 23%of its surface is also indicated regarding the surface reduction monitoring that has been done

关键词： Bedrock outcrop Citlaltépetl glacier Glacial accumulation zone Glacier retreat Glacial thickness

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Effects of Hedera helix *** on the understory early regeneration in an oak temperate forest in Mexico City

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Ecological Processes 2023年第1期12卷 438-449页

作者： Héctor Adrián Jiménez-Hernández Leticia Bonilla-valencia Yuriana martínez-Orea Mara Jessica Zamora-Almazan Francisco Javier Espinosa-García Silvia Castillo-Argüero Facultad de Ciencias Universidad Nacional Autónoma de MéxicoMexico CityMexico Instituto de Investigaciones en Ecosistemas y Sustentabilidad Universidad Nacional Autónoma de MéxicoMichoacánMexico

Background Hedera helix *** an invasive weed species introduced in several regions of the world,so it is relevant to study its effects on the plant community and the changes occurring after its *** established invaded(with/without removal of ***)and non-invaded(with/without removal of the understory)plots to compare some community attributes in an oak forest in Mexico City and monitored them every 2 months for 1 year,taking soil samples to compare some edaphic variables between the *** invasive species negatively affect natural regenera-tion,seedlings of native species would be less abundant in plots invaded by *** than in the non-invaded *** invasive species modify the soil microbiota through exudates and often allelochemicals,soil chemical variables would differ between invaded and non-invaded *** The abundance of native species was lower in the invaded plots,but the richness and diversity of species were not statistically *** composition of the two invaded plots was similar to each other and more alike to that of the non-invaded *** species composition of the invaded plots was associated with soil potassium and phosphorus concentrations,whereas that of the non-invaded plots was more associated with soil nitrogen *** Following the removal of ***,several native species were registered,leading to a similar species composition as in the non-invaded plots,suggesting that some vegetation recovery can be expected following *** removal in 1 year.

关键词： Ivy Invasive plant Mechanical control Diversity Species composition

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Non-Canonical Functions of the E2F/DP Pathway with Emphasis in Plants

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Phyton-International Journal of Experimental Botany 2021年第2期90卷 307-330页

作者： víctor A.Sánchez-Camargo Samantha Romero-Rodríguez Jorge M.vázquez-Ramos Facultad de Química Departamento de BioquímicaUniversidad Nacional Autónoma de MéxicoAvenida Universidad y CopilcoCiudad de México04510México Plant Development and(Epi)Genetics Group Swammerdam Institute for Life SciencesUniversiteit van AmsterdamAmsterdam1098XHNetherlands

The E2F/DP pathway is a widely conserved regulatory mechanism in pluricellular *** family of E2F and DP transcription factors was originally described having a role in the transition from the G1 to the S phase of the cell ***,the discovery of hundreds of possible gene targets and their involvement in many other biochemical processes,soon showed that they participated in cell development and differentiation,chromatin remodeling,DNA repair and *** E2F/DP transcription factors can act as either activators or repressors of transcription depending on their association to other regulatory proteins,particularly the retinoblastoma protein,or even depending to their protein structure that can define their *** plants the E2F/DP pathway also regulates endoreduplication,a process present along the life cycle,from organ elongation to root differentiation and *** transcription factors also help plant cells to respond to environmental disturbances such as those caused by different types of radiation,or by *** review focuses on the“so called”non-canonical functions of the E2F/DP family proteins in animal and plant cells,that are in fact essential activities that connect regulatory circuits among multiple metabolic pathways by means of their atypical functions.

关键词： E2F DP transcription factors atypical functions plant cells

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Brain-derived neurotrophic factor signaling in the neuromuscular junction during developmental axonal competition and synapse elimination

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Neural Regeneration Research 2025年第2期20卷 394-401页

作者： Josep Tomàs víctor Cilleros-Mañé Laia Just-Borràs marta Balanyà-Segura Aleksandra Polishchuk Laura Nadal marta Tomàs Carolina Silvera-Simón Manel M.Santafé Maria A.Lanuza Unitat d’Histologia i Neurobiologia(UHNeurob) Facultat de Medicina i Ciències de la SalutUniversitat Rovira i VirgiliReusSpain

During the development of the nervous system,there is an overproduction of neurons and *** competition between neighboring nerve endings and synapses performing different activity levels leads to their elimination or *** have extensively studied the involvement of the brain-derived neurotrophic factor-Tropomyosin-related kinase B receptor neurotrophic retrograde pathway,at the neuromuscular junction,in the axonal development and synapse elimination process versus the synapse *** purpose of this review is to describe the neurotrophic influence on developmental synapse elimination,in relation to other molecular pathways that we and others have found to regulate this *** particular,we summarize our published results based on transmitter release analysis and axonal counts to show the different involvement of the presynaptic acetylcholine muscarinic autoreceptors,coupled to downstream serine-threonine protein kinases A and C(PKA and PKC)and voltage-gated calcium channels,at different nerve endings in developmental *** dynamic changes that occur simultaneously in several nerve terminals and synapses converge across a postsynaptic site,influence each other,and require careful studies to individualize the mechanisms of specific *** describe an activity-dependent balance(related to the extent of transmitter release)between the presynaptic muscarinic subtypes and the neurotrophin-mediated TrkB/p75NTR pathways that can influence the timing and fate of the competitive interactions between the different axon *** downstream displacement of the PKA/PKC activity ratio to lower values,both in competing nerve terminals and at postsynaptic sites,plays a relevant role in controlling the elimination of supernumerary ***,calcium entry through L-and P/Q-subtypes of voltage-gated calcium channels(both channels are present,together with the N-type channel in developing nerve terminals)contributes to red

关键词： acetylcholine release adenosine receptors axonal competition brain-derived neurotrophic factor calcium channels motor end-plate muscarinic acetylcholine receptors postnatal synapse elimination serine kinases tropomyosin-related kinase receptorB

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